The pen shell,Atrina pectinata,distributes globally.It is one of the most important edible bivalves in east Asian countries.However,there are multiple difficulties in rearing pen shell larvae and juveniles because of ...The pen shell,Atrina pectinata,distributes globally.It is one of the most important edible bivalves in east Asian countries.However,there are multiple difficulties in rearing pen shell larvae and juveniles because of their high mortality.To understand the mechanism underlining such high mortality at the early embryonic development stage,we obtained approximately 100 million larvae during later breeding season in June,2017,and checked a large amount of mitotic chromosomal plates of the early embryos and post-spawning gonads tissue slices of their parents.The results showed that most diploid A.pectinata embryos have 17 pairs of chromosomes(2n=34)as their parents do.The first pair of particularly large chromosomes are heterotypic in some diploid embryos while they are homomorphic in others.The primary sex-determination chromosome type is XX/XY.A lot of triploid,pentaploid and aneuploid embryos with different numbers of the largest homomorphic or heteromorphic chromosomes were found due to the degeneration of overmatured parent gonads which hold normal karyotype.These larvae will die even though most of them may develop into the trochophore stage with 34 chromosomes.Genetic deficiency of chromosomes will cause a high rate of mortality in early embryos in late breeding season.These findings should enrich the current knowledge of juvenile pen shell aquaculture.展开更多
Plateau zokor(Eospalax baileyi)is a subterranean rodent and seasonal breeder.During the non-breeding season,the testicles regress,leading to the arrest of spermatogenesis and loss of fertility.The identification of th...Plateau zokor(Eospalax baileyi)is a subterranean rodent and seasonal breeder.During the non-breeding season,the testicles regress,leading to the arrest of spermatogenesis and loss of fertility.The identification of the specific germ cell type at which spermatogenesis is arrested,as well as potential regulatory factors during the non-breeding season,is important for understanding seasonal spermatogenesis in subterranean species.This study analyzed genes in spermatocytes of plateau zokor by referring to single-cell RNA results in mice.We discovered that spermatogenesis is arrested at the spermatocyte during the non-breeding season,which was corroborated via immunofluorescence staining results.The analysis of gene expression during different stages of meiotic prophase I has revealed that germ cell development may be arrested,starting from zygonema,during the non-breeding season.Meanwhile,we discovered that the apoptosis genes were up-regulated,leading to apoptosis in spermatocytes.To confirm that the germ cell differentiation was blocked during the non-breeding season due to a decrease in the androgen level,we used androgen receptor antagonist(flutamide)to intervene in the breeding season and found that the inner diameter of the seminiferous tubules was significantly reduced,spermatogenesis was arrested,and spermatocytes underwent apoptosis.This study revealed that spermatocytes are the terminal of germ cell differentiation in plateau zokor during the non-breeding season and that the arrest of differentiation is attributed to a decline in androgen levels.Our results complement the theoretical basis of seasonal reproduction in plateau zokor.展开更多
Three big field projects, independent irrigation and drainage facilities, and a blocking net, which are auxiliary projects of a green planting and breeding pattern composed of rice and red swamp crawfish （Procambarus...Three big field projects, independent irrigation and drainage facilities, and a blocking net, which are auxiliary projects of a green planting and breeding pattern composed of rice and red swamp crawfish （Procambarus clarkii）, spatial and temporal coupling technology of ＂planting rice in one season and breeding red swamp crawfish in three seasons＂, green fertilization technology, green prevention and control technology, control technology of water level, and throwing technology of bait in Lixiahe region of Jiangsu Province were introduced successively, which can provide technical support for the development of ecological planting and breeding patterns and realization of green production in paddy fields.展开更多
Background Ovarian follicular fluid(FF)is a dynamic environment that changes with the seasons,affecting follicle development,ovulation,and oocyte quality.Cells in the follicles release tiny particles called extracellu...Background Ovarian follicular fluid(FF)is a dynamic environment that changes with the seasons,affecting follicle development,ovulation,and oocyte quality.Cells in the follicles release tiny particles called extracellular vesicles(EVs)containing vital regulatory molecules,such as microRNAs(miRNAs).These miRNAs are pivotal in facilitating commu-nication within the follicles through diverse signaling and information transfer forms.EV-coupled miRNA signaling is implicated to be associated with ovarian function,follicle and oocyte growth and response to various environmen-tal insults.Herein,we investigated how seasonal variations directly influence the ovulatory and anovulatory states of ovarian follicles and how are they associated with follicular fluid EV-coupled miRNA dynamics in horses.Results Ultrasonographic monitoring and follicular fluid aspiration of preovulatory follicles in horses during the ano-vulatory(spring:non-breeding)and ovulatory(spring,summer,and fall:breeding)seasons and subsequent EV isola-tion and miRNA profiling identified significant variation in EV-miRNA cargo content.We identified 97 miRNAs with dif-ferential expression among the groups and specific clusters of miRNAs involved in the spring transition(miR-149,-200b,-206,-221,-328,and-615)and peak breeding period(including miR-143,-192,-451,-302b,-100,and let-7c).Bioinformatic analyses showed enrichments in various biological functions,e.g.,transcription factor activity,transcrip-tion and transcription regulation,nucleic acid binding,sequence-specific DNA binding,p53 signaling,and post-trans-lational modifications.Cluster analyses revealed distinct sets of significantly up-and down-regulated miRNAs associ-ated with spring anovulatory(Cluster 1)and summer ovulation–the peak breeding season(Clusters 4 and 6).Conclusions The findings from the current study shed light on the dynamics of FF-EV-coupled miRNAs in relation to equine ovulatory and anovulatory seasons,and their roles in understanding the mechanisms involved in seasonal shifts and ovulation during the breeding season warrant further investigation.展开更多
[Objectives] The aim was to improve and stabilize the estrus synchronization of local sheep in Xinjiang during the breeding season and non-breeding season. [Methods]The data of estrus rate and estrus concentration tim...[Objectives] The aim was to improve and stabilize the estrus synchronization of local sheep in Xinjiang during the breeding season and non-breeding season. [Methods]The data of estrus rate and estrus concentration time were analyzed by different hormone treatment programs. [Results]eding season,whether PMSC was used did not affect the estrus of sheep when sponge and PG were used（ P 〉 0. 05）. Estrus was concentrated in 36-48 h after sponge plugs were removed,and the estrus rate in this period accounted for 74. 19% of the total. In non-breeding season,the estrus rate in the sponge plug plus PGF treatment was only56. 12%,significantly lower than that（ 90. 43%） in the sponge plug plus PG plus PMSG treatment（ P 〈 0. 01）. The estrus was also concentrated in 36-48 h after sponge plugs were removed. The estrus rate at this stage was 67. 42%,accounting for 82. 8% of the total. In breeding season,the estrus rate in sheep injected with333 IU of PMSG（ 81. 96%） was significantly lower than those of sheep injected with 500（ 90. 25%） and 750 IU（ 95. 3%）（ P 〈 0. 05）. [Conclusions] This study provides a theoretical basis for the production enterprises to save a lot of manpower and material resources.展开更多
Background: The breeding information of most birds in Asian tropical areas,especially in limestone forests,is still poorly known.The Streaked Wren-Babbler(Napothera brevicaudata) is an uncommon tropical limestone bird...Background: The breeding information of most birds in Asian tropical areas,especially in limestone forests,is still poorly known.The Streaked Wren-Babbler(Napothera brevicaudata) is an uncommon tropical limestone bird with a small range.We studied its nest-site selection and breeding ecology,in order to understand the adaptations of birds to the conditions of tropical limestone forest in southern China.Methods: We used methods of systematical searching and parent-following to locate the nests of the Streaked Wren-Babbler.We measured characteristics of nest sites and rock cavities.Data loggers and video cameras were used to monitor the breeding behavior.Results: All the observed nests of the Streaked Wren-Babbler were placed in natural shallow cavities or deep holes in large boulders or limestone cliffs.The great majority(96.6%) of Streaked Wren-Babbler nests had three eggs with an average fresh weight of 3.46-± 0.43 g(n = 36,range 2.52-4.20 g).Most(80.4%) females laid their first eggs between March and April(n = 46).The average incubation and nestling period of the Streaked Wren-Babbler was 10.2 range 9-11 days),respectively.Most(87.9%) nests h± 0.4 days(n = 5,range 1011 days) and 10.5 ± 0.8 days(n = 6,ad at least one nestling fledge between 2011 and 2013(n = 33).Conclusions: Our study suggests that several features of the breeding ecology of the Streaked Wren-Babbler,including building nests in rocky cavities,commencing breeding earlier than most species,and reducing foraging times during the incubation period,are well-adapted to the unique habitat of tropical limestone forest.展开更多
In recent years, the demand for goat products has been growing due to the fact that goat milk has a number of advantages over cow milk, for example, it is low in lactose, and is considered less allergenic and easier t...In recent years, the demand for goat products has been growing due to the fact that goat milk has a number of advantages over cow milk, for example, it is low in lactose, and is considered less allergenic and easier to digest. To increase production during both breeding and non-breeding seasons and reduce the price of dairy products, it is necessary to effectively use reproductive management and assisted reproductive technologies. In vitro embryo production makes it possible to obtain a large number of eggs from goats, which for some reason are unable to conceive, but have genetic value. Afterward in vitro produced embryos can be transferred into recipient goats of other less genetically valuable breeds, such as the Ukrainian local breed. Therefore, the aim of the present study was to investigate the effectiveness of transfers of in vitro produced embryos of Saanen goats into surrogate sires of the Ukrainian local breed in different seasons. All manipulations with animals were carried out following ethical standards (Strasbourg, 1986). Six Saanen goats were selected as the oocyte donors. After the hormonal stimulation oocytes were retrieved by laparoscopic ovum pick-up. In vitro produced embryos were transferred laparotomically into 24 recipients of Ukrainian local breed. Fifty days after embryo transfers, pregnancies were determined by ultrasound diagnostics. Although the embryo development rate in the breeding season was 20% higher than in the non-breeding season, there was no difference in pregnancy and kidding rates between seasons. In conclusion, the transfer of in vitro produced Saanen goat embryos to recipients of the Ukrainian local breed gives the opportunity to achieve pregnancy and kidding regardless of the breeding season, which will enable a faster and more efficient increase in the livestock of highly productive goats in Ukraine in the post-war period.展开更多
There are many short-lived animals,but those displaying a lifecycle with more than one generation per year(multivoltine lifecycle)are rare amongterrestrial vertebrates.The multivoltine lifecycle requires rapid growth ...There are many short-lived animals,but those displaying a lifecycle with more than one generation per year(multivoltine lifecycle)are rare amongterrestrial vertebrates.The multivoltine lifecycle requires rapid growth and maturation and a long active season.Thus,small lizards in humidtropical or subtropical areas are candidates for multivoltine lifecycles.To test this prediction,we conducted a capture-mark-recapture study of asubtropical grass lizard,Takydromus toyamai,endemic to Miyako Islands,Japan.Juveniles grew very quickly,averaging 0.3 mm/day in the warmseason,and attained sexual maturity at 2.5 months post-hatching.The breeding season was very long,and hatchlings emerged from May toNovember.The prolonged breeding season and rapid growth to maturity allowed some individuals to produce a second generation in their frstyear.Estimates of hatching date from growth rates indicated that many females that hatched in May-June became gravid 76-120 days afterhatching and 122-165 days after oviposition of the eggs from which they hatched.Analyses of juvenile survivorship and month of hatching suggest that nearly half of breeding adults were members of multivoltine generations,although the 2 generations were not discrete.The species isshort-lived,with only 16% of individuals surviving beyond 12 months,and few individuals reproduced in a second year.We refer to this conditionas a“semi-multivoltine lifecycle.”Individuals that hatch late in the season defer reproduction until the following year and become founders ofthe next season’s cohort.This putative advantage of late-hatching individuals may have driven the evolution of this lifecycle.展开更多
A playback experiment is a well-established method for behavior research, especially in the study of the territorial responses of songbirds. Birds obtain information from multimodal signals, whereas only acoustic sign...A playback experiment is a well-established method for behavior research, especially in the study of the territorial responses of songbirds. Birds obtain information from multimodal signals, whereas only acoustic signals are provided in traditional playbacks. Many efforts have been made to combine visual signals with playback experiments, e.g., static specimens, videos, live birds and robotic models. Multimodal signal playback provides an elaborate way to study the behavior of focal birds. Although combining visual signals with playback experiments can elicit more authentic responses, empirical evidence remains scarce. In this study, a robot model mimicking a territory intruder was presented to Eurasian Nuthatch (Sitta europaea) to evaluate its effect on playback experiments. The experiments were conducted on 45 individuals during the 2021 breeding season in Baihua Mountain National Nature Reserve (39°83ʹ N, 115°58ʹ E), China. These 45 individuals were randomly divided into three equal-sized groups corresponding to the experimental treatments: playback sound only;sound with a static model;and sound with a dynamic model. Behavioral variables were recorded during each experiment to generate response intensity via principal component analysis. The results revealed that there was no significant difference in response intensity among the three different experimental treatments. Considering the dense habitat where nuthatches live, the robot model may have insufficiently increased the stimulation of sensory perception. We propose that the effect of visual signals during playback should be evaluated in more species and that behavioral studies could be conducted using multimodal signals to provide a more realistic representation of bird‒bird interactions.展开更多
There is a dearth of information on the effects of landscape and microhabitat variables on the distribution of anurans in areas of rapid urban development, in both tropical and subtropical regions. Therefore, we studi...There is a dearth of information on the effects of landscape and microhabitat variables on the distribution of anurans in areas of rapid urban development, in both tropical and subtropical regions. Therefore, we studied 24 Wetlands sites from the center of Shanghai city, China extending outward to rural areas. Sampling was performed from May through July 2014. Urbanization was categorized by the proportion of hard ground cover. Transect sampling and ＇calling＇ surveys were used to investigated the richness and density of anurans; microhabitat factors were recorded simultaneously. One-way analysis of variance and Kruskal-Wallis tests were conducted to analyze differences of total density, species richness and density of individual anuran species in the three urbanization levels; redundancy analysis was carried out on the relationship between anuran density and environmental variables. Species richness was lowest in the areas where the proportion of hard ground cover was 〉 80%, and the total density of anurans was highest in the areas where coverage of the hard ground cover was 〈 30%. We recorded five species belonging to four genera and four families and an individual anuran species that had varied representations in urban environments. Beijing gold-striped pond frogs （Pelophylax plancyi） and Zhoushan toads （Bufo gargarizans） appeared to be well adapted to the Shanghai metropolis. Large water environments and aquatic vegetation （floating-leaves and emergent vegetation） were indicators of the presence of Beijing gold-striped pond frogs. The density of black-spotted pond frog （Pelophylax nigromaculatus） was at the lowest density in the areas where hard ground coverage was 〉 80%, and tended to prefer larger bodies of water. Hong Kong rice-paddy frogs （Fejervarya multistriata） and ornamented pygmy frogs （Microhyla achatina） both suffered severely from cropland loss due to urban development. Bare land around breeding grounds was important for Hong Kong rice-paddy frogs, since it usually chooses mud coast caves for hibernation.展开更多
Body coloration and color patterns are ubiquitous throughout the animal kingdom and vary be- tween and within species. Recent studies have dealt with individual dynamics of various aspects of coloration, as it is in m...Body coloration and color patterns are ubiquitous throughout the animal kingdom and vary be- tween and within species. Recent studies have dealt with individual dynamics of various aspects of coloration, as it is in many cases a flexible trait and changes in color expression may be context-de- pendent. During the reproductive phase, temporal changes of coloration in the visible spectral range （400-700 nm） have been shown for many animals but corresponding changes in the ultravio- let （UV） waveband （300-400 nm） have rarely been studied. Threespine stickleback Gasterosteus aculeatus males develop conspicuous orange-red breeding coloration combined with UV reflect- ance in the cheek region. We investigated dynamics of color patterns including UV throughout a male breeding cycle, as well as short-term changes in coloration in response to a computer- animated rival using reflectance spectrophotometry and visual modeling, to estimate how colors would be perceived by conspecifics. We found the orange-red component of coloration to vary during the breeding cycle with respect to hue （theta/R50） and intensity （achieved chroma/red chroma）. Furthermore, color intensity in the orange-red spectral part （achieved chroma） tended to be increased after the presentation of an artificial rival. Dynamic changes in specific measures of hue and intensity in the UV waveband were not found. In general, the orange-red component of the signal seems to be dynamic with respect to color intensity and hue. This accounts in particular for color changes during the breeding cycle, presumably to signal reproductive status, and with limitations as well in the intrasexual context, most likely to signal dominance or inferiority.展开更多
On a population level,individual plasticity in reproductive phenology can provoke either anticipations or delays in the average reproductive timing in response to environmental changes.However,a rigid reliance on phot...On a population level,individual plasticity in reproductive phenology can provoke either anticipations or delays in the average reproductive timing in response to environmental changes.However,a rigid reliance on photoperiodism can constraint such plastic responses in populations inhabiting temperate latitudes.The regulation of breeding season length may represent a further tool for populations facing changing environments.Nonetheless,this skill was reported only for equatorial,nonphotoperiodic populations.Our goal was to evaluate whether species living in temperate regions and relying on photoperiodism to trigger their reproduction may also be able to regulate breeding season length.During 10 years,we collected 2,500 female reproductive traits of a mammal model species(wild boar Sus scrofa)and applied a novel analytical approach to reproductive patterns in order to observe population-level variations of reproductive timing and synchrony under different weather and resources availability conditions.Under favorable conditions,breeding seasons were anticipated and population synchrony increased(i.e.,shorter breeding seasons).Conversely,poor conditions induced delayed and less synchronous(i.e.,longer)breeding seasons.The potential to regulate breeding season length depending on environmental conditions may entail a high resilience of the population reproductive patterns against environmental changes,as highlighted by the fact that almost all mature females were reproductive every year.展开更多
Background: Grit is used by birds mainly for grinding hard food items but can also serve a nutritional role as a source of minerals. Ingestion of grit by birds has been documented primarily in species that feed on see...Background: Grit is used by birds mainly for grinding hard food items but can also serve a nutritional role as a source of minerals. Ingestion of grit by birds has been documented primarily in species that feed on seeds and invertebrates.Although feeding mainly on nectar and small arthropods, hummingbirds also ingest grit, but why they do so is unclear. We quantified the number of grit particles in the stomachs of six species of hummingbirds during an annual cycle in a seasonal ecosystem of West Mexico.Methods: We compared the number of grit particles in the stomachs of different hummingbird species(Mexican Violetear Colibri thalassinus, Amethyst-throated Mountaingem Lampornis amethystinus, White-eared Hummingbird Basilinna leucotis, Rivoli's Hummingbird Eugenes fulgens, Broad-tailed Hummingbird Selasphorus platycercus, and Rufous Hummingbird S. rufus), and between sex and age categories during the different seasons of a year. To deter-mine if grit was used to grind ingested arthropods, we examined the relationships between the number of grit parti-cles, the biomass of arthropods ingested, and their chitin content.Results: Although species did not differ in the number of grit particles in their stomachs, we found that grit was mostly ingested by female individuals, with only one male of one species(Mexican Violetear) presenting grit in its stomach. We also found that female hummingbirds had grit in their stomachs during the rainy and the cold-dry season(June-February) but not during the warm-dry season(March-May). Our analyses revealed no relationship between the number of grit particles and the amount of ingested arthropods and arthropod chitin content. However,high grit consumption was related to wasp ingestion on Mexican Violetears.Conclusions: Our results indicate that grit is used mainly by female hummingbirds. The seasonal variation in the ingestion of grit by female individuals suggests that it can be used to meet mineral requirements related to breed-ing;however, this topic needs further exploration. Additionally, the use of grit was proportionally higher in juvenile individuals, suggesting it is used for grinding arthropods during a period of fast development.展开更多
The reproductive behaviors of birds are mainly controlled by the hypothalamus-pituitary-gonad axis.Many studies have shown that reproductive hormones are tightly linked to the breeding sub-stages.However,only a few st...The reproductive behaviors of birds are mainly controlled by the hypothalamus-pituitary-gonad axis.Many studies have shown that reproductive hormones are tightly linked to the breeding sub-stages.However,only a few studies have examined the temporal trend of hormone levels among different reproductive stages in multiple brooded species.We investigated the changes in plasma luteinizing hormone(LH)and prolactin(PRL)concentrations during different reproductive stages of the facultative double-brooded Great Tit(Parus major).We found that the concentrations of LH and PRL in females were significantly higher than those in males.Females had significantly higher LH and lower PRL concentrations in the pre-breeding period than in the first/second brooding periods,and there were no significant changes between the first and second brooding periods.The concentrations of LH and PRL in males had no significant difference between the pre-breeding period and the first brooding periods,while LH and PRL concentrations in the second brooding period were significantly higher than those in the first brooding period.We conclude that there are sex-based differences between LH and PRL at different stages of reproduction.The changes in LH and PRL in both males and females should be related to their physiological functions.Especially for males,individuals with higher levels of LH and PRL are more likely to maintain second clutches.展开更多
Dear Editor,Roots,as a major organ of plants,are involved in nutrient and water acquisition,and might play a vital role in yield increase and efficient N absorption with genetic improvement.Because of the great differ...Dear Editor,Roots,as a major organ of plants,are involved in nutrient and water acquisition,and might play a vital role in yield increase and efficient N absorption with genetic improvement.Because of the great differences in growth period and pattern between the old and new rice cultivars,it is difficult to clarify how genetic improvements contribute to root growth in rice.展开更多
Tilapiine breeding success is season-dependent,with very rare exceptions.The female(f)to male(m)ratio differences showed significant variations in fruitful breeding.Furthermore,the female-to-male ratio in any hybridiz...Tilapiine breeding success is season-dependent,with very rare exceptions.The female(f)to male(m)ratio differences showed significant variations in fruitful breeding.Furthermore,the female-to-male ratio in any hybridization protocol involving reciprocal crosses may be the most influential factor in determining breeding seasonality.The innate genetic traits of tilapia,a prominent contributor to global aquaculture production,enable them to easily adapt to a wide range of aquatic environments,rendering them suitable for domestication.The study aimed to determine the breeding timeframe of Nile tilapia(Oreochromis niloticus,N)through interspecific monogamous/two-parent reciprocal crossing with Mozambique tilapia(O.mossambicus,M).Considering preselected genotypic characteristics by PrlLK microsatellite marker,different combinations of hybrid reciprocal crosses were performed in breeding hapa(3×3×3 cubic feet)inside an indoor plastered cemented tank and then in an outdoor earthen pond facility.Total 11 parental pairs were attempted to propagate inside a cemented tank with(9 pairs)and without(2 pairs)hapa during early April to mid-June.Unfortunately,the trials failed to produce any successful breeding within the schedule.Among those 11 pairs,6 pairs were Nf×Mm and 5 pairs were Mf×Nm cross.In the earthen pond inside hapa,a total of 18 pairs were attempted where seven breeding successes were reported without demonstrating any dependency for hybridizations over cross types or genotypes and for individuals over sex or species.Successful breeding were reported from the month of May to November.There were few overlapping months of successful breeding for different grouping categories.During the successful breeding period,there were no successful outcomes in both August and October.An inadvertent all-female F1 generation was observed for Mf×Nm crosses,while the reciprocal cross Nf×Mm produced an F1 generation with a nearly 1:1 female to male ratio.The F1 sex ratios exhibited a significant reliance on parental genotypic combinations(p=5.4e-11).The success stories from different cross combinations would help to frame the breeding protocol for future research.More precisely,for arranging a breeding schedule in freshwater earthen ponds inside hapa for a monogamous/two-parent hybrid cross the study light a close insight.展开更多
Photoperiod,the length of daylight,has a significant impact on the physiological characteristics of seasonal breeding animals,including their somatic and gonadal development.In rodents,expression of deiodinase type II...Photoperiod,the length of daylight,has a significant impact on the physiological characteristics of seasonal breeding animals,including their somatic and gonadal development.In rodents,expression of deiodinase type II(Dio2)and III(Dio3)in the hypothalamus is crucial for responding to photoperiodic signals.However,research on the photoperiodism of hypothalamic gene expression and the corresponding regulatory mechanism in Brandt’s voles living in the Mongolian steppes is limited.In this study,we gradually changed day length patterns to simulate spring(increasing long photoperiod,ILP)and autumn(decreasing short photoperiod,DSP).We compared the somatic and gonadal development of voles born under ILP and DSP and the expression patterns of five reproductionrelated genes in the hypothalamus of young voles.The results showed that DSP significantly inhibited somatic and gonadal development in both female and male offspring.Compared with ILP,Dio3 expression was significantly upregulated in the hypothalamus under DSP conditions and remained elevated until postnatal week 8 in both males and females.However,there was no significant difference in the methylation levels of the proximal promoter region of Dio3 between ILP and DSP,suggesting that methylation in the proximal promoter region may not be involved in regulating the expression of Dio3.These findings suggest that hypothalamic expression of Dio3 plays a key role in the photoperiodic regulation of gonadal activity in Brandt’s voles.However,it appears that CpGs methylation in the promoter region is not the main mechanism regulating Dio3 expression.展开更多
Objective:To know spatial,temporal distributions and some biological aspects of commercially important fish species of Lake Tana.Methods:Distribution of fish species in Lake Tana was studied from November 2009 to Octo...Objective:To know spatial,temporal distributions and some biological aspects of commercially important fish species of Lake Tana.Methods:Distribution of fish species in Lake Tana was studied from November 2009 to October 2012 based on samples collected every other month using gillnets of 60,80,100,120 and 140 mm stretched mesh sizes.Labeobarbus species,Clarias gariepinus,Oreochromis niloticus,and Varicorhinus beso are commercially important fish species and form 68%,18%,14%and 0.5%of the pooled experimental fish catch.There was significant variability among years and sampling sites of both temporal and spatial aspects;Mann-Whitney U tests were used for pair wise comparisons of sites and years.Results:The composition of Labeobarbus spp.and Varicorhinus beso shows significant decline.On the other hand,the composition of Oreochromis niloticus did not change,but Clarias gariepinus increased by 100%by catch composition.The most likely explanations for the total decline in abundance of fish species are the increase of the illegal commercial gillnet fishery targeting their spawning aggregations in the wetlands and river mouths,and the increasing trend of the degradation of spawning and nursery habitats both in the lake and major tributary rivers of the catchment area.Conclusions:There should be a need for urgent development of a management plan focusing on ensuring sustainable utilization of a resource by fishing effort,gear mesh size and gear type restrictions,and controlling the spawning grounds from different types of human encroachment and designing closing seasons and spawning grounds during the breeding seasons of different fish species of Lake Tana.展开更多
Present work evaluated the possible impact of choline on metabolic enzymes of cultured fish species into a semi-intensive pond culture system,reared with Catla catla(catla),Labeo rohita(rahu),Clarias batracus(magur)an...Present work evaluated the possible impact of choline on metabolic enzymes of cultured fish species into a semi-intensive pond culture system,reared with Catla catla(catla),Labeo rohita(rahu),Clarias batracus(magur)and Anabas testudineus(climbing perch)for 90 days in two seasons.Choline was added directly into the pond water periodically throughout the experimental tenure.The water quality parameters of each experimental pond were monitored and were analyzed in 15 days interval throughout the experimental tenure in both the seasons.Results were compared with treatment as choline-fed and control as non-choline-fed conditions during breeding(June-Aug.)and dry(Nov.-Jan.)seasons.The metabolic enzymes,viz.,LDH(Lactate dehydrogenase),MDH(Malate dehydrogenase),and G6PDH(Glucose-6-phosphate dehydrogenase)activities in the muscle,liver,and AchE(Acetylcholine esterase)activity in the brain and muscle revealed maximum significantly(p<0.01),but ALT(Alanine aminotransferase)and AST(Aspartate aminotransferase)activity showed significant(p<0.01)depletion in the muscle and liver in treatment-breeding(TB)condition.The fishes under treatment-dry(TD)condition presented significant(p<0.01)higher elevation in HK(Hexokinase)activity in the muscle and liver.Additionally,the result of principal component analysis(PCA)depicted the positive as well as in some cases a negative correlation among the enzymatic activities both in dry and breeding seasons.So,it can be inferred that choline enrichment in fishes can substantiate the well nutritionally balanced food-flesh for consumption under this farm culture and the choline behaved as a positive contaminant into the pond eco-system under the semi-intensive culture condition.展开更多
The use of daily torpor and/or of multi-day torpor bouts during a hibernation season are energy-saving survival strategies that have been well-studied for many years,particularly for small mammals living in seasonally...The use of daily torpor and/or of multi-day torpor bouts during a hibernation season are energy-saving survival strategies that have been well-studied for many years,particularly for small mammals living in seasonally-cold environments.Both phenomena are characterized by a regulated suppression of metabolic rate,展开更多
基金part by the Central Public-Interest Scientific Institution Basal Research Fund,YSFRI,CAFS,China(No.20603022018004)the National Natural Science Foundation of China(No.31672637)+1 种基金the National Key R&D Program of China(No.2018YFD0900800)the Key Research and Development Plan of Shandong Province,China(No.2016GSF115012).
文摘The pen shell,Atrina pectinata,distributes globally.It is one of the most important edible bivalves in east Asian countries.However,there are multiple difficulties in rearing pen shell larvae and juveniles because of their high mortality.To understand the mechanism underlining such high mortality at the early embryonic development stage,we obtained approximately 100 million larvae during later breeding season in June,2017,and checked a large amount of mitotic chromosomal plates of the early embryos and post-spawning gonads tissue slices of their parents.The results showed that most diploid A.pectinata embryos have 17 pairs of chromosomes(2n=34)as their parents do.The first pair of particularly large chromosomes are heterotypic in some diploid embryos while they are homomorphic in others.The primary sex-determination chromosome type is XX/XY.A lot of triploid,pentaploid and aneuploid embryos with different numbers of the largest homomorphic or heteromorphic chromosomes were found due to the degeneration of overmatured parent gonads which hold normal karyotype.These larvae will die even though most of them may develop into the trochophore stage with 34 chromosomes.Genetic deficiency of chromosomes will cause a high rate of mortality in early embryos in late breeding season.These findings should enrich the current knowledge of juvenile pen shell aquaculture.
基金supported by an Open Project of the Key Laboratory of Grassland Ecosystem(Gansu Agricultural University),Ministry of Education(KLGE202204)the“Innovation Star”project of Gansu Province’s outstanding graduate students(2023CXZX-621)+1 种基金the National Natural Science Foundation of China(32272566 and 31760706)the Industrial Support Program Project(2022CYZC-47)of Gansu Provincial Education Department.
文摘Plateau zokor(Eospalax baileyi)is a subterranean rodent and seasonal breeder.During the non-breeding season,the testicles regress,leading to the arrest of spermatogenesis and loss of fertility.The identification of the specific germ cell type at which spermatogenesis is arrested,as well as potential regulatory factors during the non-breeding season,is important for understanding seasonal spermatogenesis in subterranean species.This study analyzed genes in spermatocytes of plateau zokor by referring to single-cell RNA results in mice.We discovered that spermatogenesis is arrested at the spermatocyte during the non-breeding season,which was corroborated via immunofluorescence staining results.The analysis of gene expression during different stages of meiotic prophase I has revealed that germ cell development may be arrested,starting from zygonema,during the non-breeding season.Meanwhile,we discovered that the apoptosis genes were up-regulated,leading to apoptosis in spermatocytes.To confirm that the germ cell differentiation was blocked during the non-breeding season due to a decrease in the androgen level,we used androgen receptor antagonist(flutamide)to intervene in the breeding season and found that the inner diameter of the seminiferous tubules was significantly reduced,spermatogenesis was arrested,and spermatocytes underwent apoptosis.This study revealed that spermatocytes are the terminal of germ cell differentiation in plateau zokor during the non-breeding season and that the arrest of differentiation is attributed to a decline in androgen levels.Our results complement the theoretical basis of seasonal reproduction in plateau zokor.
基金Supported by Gaoyou Demonstration and Extension Base of Modern Agricultural(Rice and Wheat)Industrial Technology System in Jiangsu(SXGC[2017]168)Funds for Independent Innovation of Jiangsu Province(CX17(2007),KF(17)1022)+1 种基金Key Research and Development Plan Project(BE2017332)Agricultural Standardization Pilot Project of Jiangsu Province([2017]46)~~
文摘Three big field projects, independent irrigation and drainage facilities, and a blocking net, which are auxiliary projects of a green planting and breeding pattern composed of rice and red swamp crawfish （Procambarus clarkii）, spatial and temporal coupling technology of ＂planting rice in one season and breeding red swamp crawfish in three seasons＂, green fertilization technology, green prevention and control technology, control technology of water level, and throwing technology of bait in Lixiahe region of Jiangsu Province were introduced successively, which can provide technical support for the development of ecological planting and breeding patterns and realization of green production in paddy fields.
基金Southern Illinois University,Carbondale,ILMinistry of Higher Education&Scientific Research,Baghdad,Iraq+2 种基金NIFA-USDA Hatch project accession#1016077(Multistate#W4171)USDAARS project 6066-31000-015-00DNIH MS-IDeA network of Biomedical Research Excellence award 5P20GMI03476-19.GMI received a PhD scholarship from the Ministry of Higher Education&Scientific Research,Baghdad,Iraq.
文摘Background Ovarian follicular fluid(FF)is a dynamic environment that changes with the seasons,affecting follicle development,ovulation,and oocyte quality.Cells in the follicles release tiny particles called extracellular vesicles(EVs)containing vital regulatory molecules,such as microRNAs(miRNAs).These miRNAs are pivotal in facilitating commu-nication within the follicles through diverse signaling and information transfer forms.EV-coupled miRNA signaling is implicated to be associated with ovarian function,follicle and oocyte growth and response to various environmen-tal insults.Herein,we investigated how seasonal variations directly influence the ovulatory and anovulatory states of ovarian follicles and how are they associated with follicular fluid EV-coupled miRNA dynamics in horses.Results Ultrasonographic monitoring and follicular fluid aspiration of preovulatory follicles in horses during the ano-vulatory(spring:non-breeding)and ovulatory(spring,summer,and fall:breeding)seasons and subsequent EV isola-tion and miRNA profiling identified significant variation in EV-miRNA cargo content.We identified 97 miRNAs with dif-ferential expression among the groups and specific clusters of miRNAs involved in the spring transition(miR-149,-200b,-206,-221,-328,and-615)and peak breeding period(including miR-143,-192,-451,-302b,-100,and let-7c).Bioinformatic analyses showed enrichments in various biological functions,e.g.,transcription factor activity,transcrip-tion and transcription regulation,nucleic acid binding,sequence-specific DNA binding,p53 signaling,and post-trans-lational modifications.Cluster analyses revealed distinct sets of significantly up-and down-regulated miRNAs associ-ated with spring anovulatory(Cluster 1)and summer ovulation–the peak breeding season(Clusters 4 and 6).Conclusions The findings from the current study shed light on the dynamics of FF-EV-coupled miRNAs in relation to equine ovulatory and anovulatory seasons,and their roles in understanding the mechanisms involved in seasonal shifts and ovulation during the breeding season warrant further investigation.
基金Supported by Nonprofit Institute Research Grant of Autonomous Region(KY2017008)Guiding Fund Project for Scientific and Technological Innovation in Inner Mongolia Autonomous Region+1 种基金Meat Sheep Industry Engineering Technology Research Center of Inner Mongolia Autonomous RegionDorper×Mongolia Sheep Breeding and Industrialization
文摘[Objectives] The aim was to improve and stabilize the estrus synchronization of local sheep in Xinjiang during the breeding season and non-breeding season. [Methods]The data of estrus rate and estrus concentration time were analyzed by different hormone treatment programs. [Results]eding season,whether PMSC was used did not affect the estrus of sheep when sponge and PG were used（ P 〉 0. 05）. Estrus was concentrated in 36-48 h after sponge plugs were removed,and the estrus rate in this period accounted for 74. 19% of the total. In non-breeding season,the estrus rate in the sponge plug plus PGF treatment was only56. 12%,significantly lower than that（ 90. 43%） in the sponge plug plus PG plus PMSG treatment（ P 〈 0. 01）. The estrus was also concentrated in 36-48 h after sponge plugs were removed. The estrus rate at this stage was 67. 42%,accounting for 82. 8% of the total. In breeding season,the estrus rate in sheep injected with333 IU of PMSG（ 81. 96%） was significantly lower than those of sheep injected with 500（ 90. 25%） and 750 IU（ 95. 3%）（ P 〈 0. 05）. [Conclusions] This study provides a theoretical basis for the production enterprises to save a lot of manpower and material resources.
基金supported by the National Natural Science Foundation of China(30970381,31460567)Guangxi(2010GXNSFB013044)a postdoctoral start-up project of Guangxi University(Y336002006,B41049)
文摘Background: The breeding information of most birds in Asian tropical areas,especially in limestone forests,is still poorly known.The Streaked Wren-Babbler(Napothera brevicaudata) is an uncommon tropical limestone bird with a small range.We studied its nest-site selection and breeding ecology,in order to understand the adaptations of birds to the conditions of tropical limestone forest in southern China.Methods: We used methods of systematical searching and parent-following to locate the nests of the Streaked Wren-Babbler.We measured characteristics of nest sites and rock cavities.Data loggers and video cameras were used to monitor the breeding behavior.Results: All the observed nests of the Streaked Wren-Babbler were placed in natural shallow cavities or deep holes in large boulders or limestone cliffs.The great majority(96.6%) of Streaked Wren-Babbler nests had three eggs with an average fresh weight of 3.46-± 0.43 g(n = 36,range 2.52-4.20 g).Most(80.4%) females laid their first eggs between March and April(n = 46).The average incubation and nestling period of the Streaked Wren-Babbler was 10.2 range 9-11 days),respectively.Most(87.9%) nests h± 0.4 days(n = 5,range 1011 days) and 10.5 ± 0.8 days(n = 6,ad at least one nestling fledge between 2011 and 2013(n = 33).Conclusions: Our study suggests that several features of the breeding ecology of the Streaked Wren-Babbler,including building nests in rocky cavities,commencing breeding earlier than most species,and reducing foraging times during the incubation period,are well-adapted to the unique habitat of tropical limestone forest.
文摘In recent years, the demand for goat products has been growing due to the fact that goat milk has a number of advantages over cow milk, for example, it is low in lactose, and is considered less allergenic and easier to digest. To increase production during both breeding and non-breeding seasons and reduce the price of dairy products, it is necessary to effectively use reproductive management and assisted reproductive technologies. In vitro embryo production makes it possible to obtain a large number of eggs from goats, which for some reason are unable to conceive, but have genetic value. Afterward in vitro produced embryos can be transferred into recipient goats of other less genetically valuable breeds, such as the Ukrainian local breed. Therefore, the aim of the present study was to investigate the effectiveness of transfers of in vitro produced embryos of Saanen goats into surrogate sires of the Ukrainian local breed in different seasons. All manipulations with animals were carried out following ethical standards (Strasbourg, 1986). Six Saanen goats were selected as the oocyte donors. After the hormonal stimulation oocytes were retrieved by laparoscopic ovum pick-up. In vitro produced embryos were transferred laparotomically into 24 recipients of Ukrainian local breed. Fifty days after embryo transfers, pregnancies were determined by ultrasound diagnostics. Although the embryo development rate in the breeding season was 20% higher than in the non-breeding season, there was no difference in pregnancy and kidding rates between seasons. In conclusion, the transfer of in vitro produced Saanen goat embryos to recipients of the Ukrainian local breed gives the opportunity to achieve pregnancy and kidding regardless of the breeding season, which will enable a faster and more efficient increase in the livestock of highly productive goats in Ukraine in the post-war period.
基金supported fnancially by the Nanseishoto Project of WWFJ,Pro Natura Foundation Japan’s 31st Pro Natura Fundthe Project for Biodiversity Conservation Promotion of the Japan Ministry of the Environment.
文摘There are many short-lived animals,but those displaying a lifecycle with more than one generation per year(multivoltine lifecycle)are rare amongterrestrial vertebrates.The multivoltine lifecycle requires rapid growth and maturation and a long active season.Thus,small lizards in humidtropical or subtropical areas are candidates for multivoltine lifecycles.To test this prediction,we conducted a capture-mark-recapture study of asubtropical grass lizard,Takydromus toyamai,endemic to Miyako Islands,Japan.Juveniles grew very quickly,averaging 0.3 mm/day in the warmseason,and attained sexual maturity at 2.5 months post-hatching.The breeding season was very long,and hatchlings emerged from May toNovember.The prolonged breeding season and rapid growth to maturity allowed some individuals to produce a second generation in their frstyear.Estimates of hatching date from growth rates indicated that many females that hatched in May-June became gravid 76-120 days afterhatching and 122-165 days after oviposition of the eggs from which they hatched.Analyses of juvenile survivorship and month of hatching suggest that nearly half of breeding adults were members of multivoltine generations,although the 2 generations were not discrete.The species isshort-lived,with only 16% of individuals surviving beyond 12 months,and few individuals reproduced in a second year.We refer to this conditionas a“semi-multivoltine lifecycle.”Individuals that hatch late in the season defer reproduction until the following year and become founders ofthe next season’s cohort.This putative advantage of late-hatching individuals may have driven the evolution of this lifecycle.
基金supported by the National Natural Science Foundation of China(No.32170491)the Scientific Research Team Project of the College of Life Sciences,Beijing Normal University,in 2024.
文摘A playback experiment is a well-established method for behavior research, especially in the study of the territorial responses of songbirds. Birds obtain information from multimodal signals, whereas only acoustic signals are provided in traditional playbacks. Many efforts have been made to combine visual signals with playback experiments, e.g., static specimens, videos, live birds and robotic models. Multimodal signal playback provides an elaborate way to study the behavior of focal birds. Although combining visual signals with playback experiments can elicit more authentic responses, empirical evidence remains scarce. In this study, a robot model mimicking a territory intruder was presented to Eurasian Nuthatch (Sitta europaea) to evaluate its effect on playback experiments. The experiments were conducted on 45 individuals during the 2021 breeding season in Baihua Mountain National Nature Reserve (39°83ʹ N, 115°58ʹ E), China. These 45 individuals were randomly divided into three equal-sized groups corresponding to the experimental treatments: playback sound only;sound with a static model;and sound with a dynamic model. Behavioral variables were recorded during each experiment to generate response intensity via principal component analysis. The results revealed that there was no significant difference in response intensity among the three different experimental treatments. Considering the dense habitat where nuthatches live, the robot model may have insufficiently increased the stimulation of sensory perception. We propose that the effect of visual signals during playback should be evaluated in more species and that behavioral studies could be conducted using multimodal signals to provide a more realistic representation of bird‒bird interactions.
基金supported by research funding and permits from Shanghai Landscaping and City Appearance Administrative Bureau (Grant No.F131508)
文摘There is a dearth of information on the effects of landscape and microhabitat variables on the distribution of anurans in areas of rapid urban development, in both tropical and subtropical regions. Therefore, we studied 24 Wetlands sites from the center of Shanghai city, China extending outward to rural areas. Sampling was performed from May through July 2014. Urbanization was categorized by the proportion of hard ground cover. Transect sampling and ＇calling＇ surveys were used to investigated the richness and density of anurans; microhabitat factors were recorded simultaneously. One-way analysis of variance and Kruskal-Wallis tests were conducted to analyze differences of total density, species richness and density of individual anuran species in the three urbanization levels; redundancy analysis was carried out on the relationship between anuran density and environmental variables. Species richness was lowest in the areas where the proportion of hard ground cover was 〉 80%, and the total density of anurans was highest in the areas where coverage of the hard ground cover was 〈 30%. We recorded five species belonging to four genera and four families and an individual anuran species that had varied representations in urban environments. Beijing gold-striped pond frogs （Pelophylax plancyi） and Zhoushan toads （Bufo gargarizans） appeared to be well adapted to the Shanghai metropolis. Large water environments and aquatic vegetation （floating-leaves and emergent vegetation） were indicators of the presence of Beijing gold-striped pond frogs. The density of black-spotted pond frog （Pelophylax nigromaculatus） was at the lowest density in the areas where hard ground coverage was 〉 80%, and tended to prefer larger bodies of water. Hong Kong rice-paddy frogs （Fejervarya multistriata） and ornamented pygmy frogs （Microhyla achatina） both suffered severely from cropland loss due to urban development. Bare land around breeding grounds was important for Hong Kong rice-paddy frogs, since it usually chooses mud coast caves for hibernation.
文摘Body coloration and color patterns are ubiquitous throughout the animal kingdom and vary be- tween and within species. Recent studies have dealt with individual dynamics of various aspects of coloration, as it is in many cases a flexible trait and changes in color expression may be context-de- pendent. During the reproductive phase, temporal changes of coloration in the visible spectral range （400-700 nm） have been shown for many animals but corresponding changes in the ultravio- let （UV） waveband （300-400 nm） have rarely been studied. Threespine stickleback Gasterosteus aculeatus males develop conspicuous orange-red breeding coloration combined with UV reflect- ance in the cheek region. We investigated dynamics of color patterns including UV throughout a male breeding cycle, as well as short-term changes in coloration in response to a computer- animated rival using reflectance spectrophotometry and visual modeling, to estimate how colors would be perceived by conspecifics. We found the orange-red component of coloration to vary during the breeding cycle with respect to hue （theta/R50） and intensity （achieved chroma/red chroma）. Furthermore, color intensity in the orange-red spectral part （achieved chroma） tended to be increased after the presentation of an artificial rival. Dynamic changes in specific measures of hue and intensity in the UV waveband were not found. In general, the orange-red component of the signal seems to be dynamic with respect to color intensity and hue. This accounts in particular for color changes during the breeding cycle, presumably to signal reproductive status, and with limitations as well in the intrasexual context, most likely to signal dominance or inferiority.
基金The Provincial Administration of Arezzo and the Italian Ministry of Education,University and Research(PRIN 2010-2011,20108 TZKHC)financially and logistically supported the research.S.G.was supported by the FAR 2020 of the University of Sassari.
文摘On a population level,individual plasticity in reproductive phenology can provoke either anticipations or delays in the average reproductive timing in response to environmental changes.However,a rigid reliance on photoperiodism can constraint such plastic responses in populations inhabiting temperate latitudes.The regulation of breeding season length may represent a further tool for populations facing changing environments.Nonetheless,this skill was reported only for equatorial,nonphotoperiodic populations.Our goal was to evaluate whether species living in temperate regions and relying on photoperiodism to trigger their reproduction may also be able to regulate breeding season length.During 10 years,we collected 2,500 female reproductive traits of a mammal model species(wild boar Sus scrofa)and applied a novel analytical approach to reproductive patterns in order to observe population-level variations of reproductive timing and synchrony under different weather and resources availability conditions.Under favorable conditions,breeding seasons were anticipated and population synchrony increased(i.e.,shorter breeding seasons).Conversely,poor conditions induced delayed and less synchronous(i.e.,longer)breeding seasons.The potential to regulate breeding season length depending on environmental conditions may entail a high resilience of the population reproductive patterns against environmental changes,as highlighted by the fact that almost all mature females were reproductive every year.
文摘Background: Grit is used by birds mainly for grinding hard food items but can also serve a nutritional role as a source of minerals. Ingestion of grit by birds has been documented primarily in species that feed on seeds and invertebrates.Although feeding mainly on nectar and small arthropods, hummingbirds also ingest grit, but why they do so is unclear. We quantified the number of grit particles in the stomachs of six species of hummingbirds during an annual cycle in a seasonal ecosystem of West Mexico.Methods: We compared the number of grit particles in the stomachs of different hummingbird species(Mexican Violetear Colibri thalassinus, Amethyst-throated Mountaingem Lampornis amethystinus, White-eared Hummingbird Basilinna leucotis, Rivoli's Hummingbird Eugenes fulgens, Broad-tailed Hummingbird Selasphorus platycercus, and Rufous Hummingbird S. rufus), and between sex and age categories during the different seasons of a year. To deter-mine if grit was used to grind ingested arthropods, we examined the relationships between the number of grit parti-cles, the biomass of arthropods ingested, and their chitin content.Results: Although species did not differ in the number of grit particles in their stomachs, we found that grit was mostly ingested by female individuals, with only one male of one species(Mexican Violetear) presenting grit in its stomach. We also found that female hummingbirds had grit in their stomachs during the rainy and the cold-dry season(June-February) but not during the warm-dry season(March-May). Our analyses revealed no relationship between the number of grit particles and the amount of ingested arthropods and arthropod chitin content. However,high grit consumption was related to wasp ingestion on Mexican Violetears.Conclusions: Our results indicate that grit is used mainly by female hummingbirds. The seasonal variation in the ingestion of grit by female individuals suggests that it can be used to meet mineral requirements related to breed-ing;however, this topic needs further exploration. Additionally, the use of grit was proportionally higher in juvenile individuals, suggesting it is used for grinding arthropods during a period of fast development.
基金supported by the National Natural Science Foundation of China (No.31770419 and 31971402 to HW,32001094 and 31870368 to JY)
文摘The reproductive behaviors of birds are mainly controlled by the hypothalamus-pituitary-gonad axis.Many studies have shown that reproductive hormones are tightly linked to the breeding sub-stages.However,only a few studies have examined the temporal trend of hormone levels among different reproductive stages in multiple brooded species.We investigated the changes in plasma luteinizing hormone(LH)and prolactin(PRL)concentrations during different reproductive stages of the facultative double-brooded Great Tit(Parus major).We found that the concentrations of LH and PRL in females were significantly higher than those in males.Females had significantly higher LH and lower PRL concentrations in the pre-breeding period than in the first/second brooding periods,and there were no significant changes between the first and second brooding periods.The concentrations of LH and PRL in males had no significant difference between the pre-breeding period and the first brooding periods,while LH and PRL concentrations in the second brooding period were significantly higher than those in the first brooding period.We conclude that there are sex-based differences between LH and PRL at different stages of reproduction.The changes in LH and PRL in both males and females should be related to their physiological functions.Especially for males,individuals with higher levels of LH and PRL are more likely to maintain second clutches.
基金supported by the Zhejiang Provincial Natural Science Foundation (LY16C130006)the Basic Research Foundation of National Commonweal Research Institute (2014RG004-3)the National Natural Science Foundation (31501272)
文摘Dear Editor,Roots,as a major organ of plants,are involved in nutrient and water acquisition,and might play a vital role in yield increase and efficient N absorption with genetic improvement.Because of the great differences in growth period and pattern between the old and new rice cultivars,it is difficult to clarify how genetic improvements contribute to root growth in rice.
基金supported by a grant of BAS-USDA Program Project(BAS-USDA-PALS-BAU–FI–43),Bangladesh to M Sadiqul Islam.
文摘Tilapiine breeding success is season-dependent,with very rare exceptions.The female(f)to male(m)ratio differences showed significant variations in fruitful breeding.Furthermore,the female-to-male ratio in any hybridization protocol involving reciprocal crosses may be the most influential factor in determining breeding seasonality.The innate genetic traits of tilapia,a prominent contributor to global aquaculture production,enable them to easily adapt to a wide range of aquatic environments,rendering them suitable for domestication.The study aimed to determine the breeding timeframe of Nile tilapia(Oreochromis niloticus,N)through interspecific monogamous/two-parent reciprocal crossing with Mozambique tilapia(O.mossambicus,M).Considering preselected genotypic characteristics by PrlLK microsatellite marker,different combinations of hybrid reciprocal crosses were performed in breeding hapa(3×3×3 cubic feet)inside an indoor plastered cemented tank and then in an outdoor earthen pond facility.Total 11 parental pairs were attempted to propagate inside a cemented tank with(9 pairs)and without(2 pairs)hapa during early April to mid-June.Unfortunately,the trials failed to produce any successful breeding within the schedule.Among those 11 pairs,6 pairs were Nf×Mm and 5 pairs were Mf×Nm cross.In the earthen pond inside hapa,a total of 18 pairs were attempted where seven breeding successes were reported without demonstrating any dependency for hybridizations over cross types or genotypes and for individuals over sex or species.Successful breeding were reported from the month of May to November.There were few overlapping months of successful breeding for different grouping categories.During the successful breeding period,there were no successful outcomes in both August and October.An inadvertent all-female F1 generation was observed for Mf×Nm crosses,while the reciprocal cross Nf×Mm produced an F1 generation with a nearly 1:1 female to male ratio.The F1 sex ratios exhibited a significant reliance on parental genotypic combinations(p=5.4e-11).The success stories from different cross combinations would help to frame the breeding protocol for future research.More precisely,for arranging a breeding schedule in freshwater earthen ponds inside hapa for a monogamous/two-parent hybrid cross the study light a close insight.
基金supported by the National Natural Science Foundation of China(31972284,32090022,32372571,and 31471790)the Xinjiang Tian-Chi Talents Introduction Program and the Project of Northern Agriculture and Livestock Husbandary Technical Innovation Center,Chinese Academy of Agricultural Sciencies(BFGJ2022007).
文摘Photoperiod,the length of daylight,has a significant impact on the physiological characteristics of seasonal breeding animals,including their somatic and gonadal development.In rodents,expression of deiodinase type II(Dio2)and III(Dio3)in the hypothalamus is crucial for responding to photoperiodic signals.However,research on the photoperiodism of hypothalamic gene expression and the corresponding regulatory mechanism in Brandt’s voles living in the Mongolian steppes is limited.In this study,we gradually changed day length patterns to simulate spring(increasing long photoperiod,ILP)and autumn(decreasing short photoperiod,DSP).We compared the somatic and gonadal development of voles born under ILP and DSP and the expression patterns of five reproductionrelated genes in the hypothalamus of young voles.The results showed that DSP significantly inhibited somatic and gonadal development in both female and male offspring.Compared with ILP,Dio3 expression was significantly upregulated in the hypothalamus under DSP conditions and remained elevated until postnatal week 8 in both males and females.However,there was no significant difference in the methylation levels of the proximal promoter region of Dio3 between ILP and DSP,suggesting that methylation in the proximal promoter region may not be involved in regulating the expression of Dio3.These findings suggest that hypothalamic expression of Dio3 plays a key role in the photoperiodic regulation of gonadal activity in Brandt’s voles.However,it appears that CpGs methylation in the promoter region is not the main mechanism regulating Dio3 expression.
基金Supported by Ethiopian Institute of Agricultural Research(EIAR)(Grant No.Ls/Fm/Fi4/BF-2012/16).
文摘Objective:To know spatial,temporal distributions and some biological aspects of commercially important fish species of Lake Tana.Methods:Distribution of fish species in Lake Tana was studied from November 2009 to October 2012 based on samples collected every other month using gillnets of 60,80,100,120 and 140 mm stretched mesh sizes.Labeobarbus species,Clarias gariepinus,Oreochromis niloticus,and Varicorhinus beso are commercially important fish species and form 68%,18%,14%and 0.5%of the pooled experimental fish catch.There was significant variability among years and sampling sites of both temporal and spatial aspects;Mann-Whitney U tests were used for pair wise comparisons of sites and years.Results:The composition of Labeobarbus spp.and Varicorhinus beso shows significant decline.On the other hand,the composition of Oreochromis niloticus did not change,but Clarias gariepinus increased by 100%by catch composition.The most likely explanations for the total decline in abundance of fish species are the increase of the illegal commercial gillnet fishery targeting their spawning aggregations in the wetlands and river mouths,and the increasing trend of the degradation of spawning and nursery habitats both in the lake and major tributary rivers of the catchment area.Conclusions:There should be a need for urgent development of a management plan focusing on ensuring sustainable utilization of a resource by fishing effort,gear mesh size and gear type restrictions,and controlling the spawning grounds from different types of human encroachment and designing closing seasons and spawning grounds during the breeding seasons of different fish species of Lake Tana.
文摘Present work evaluated the possible impact of choline on metabolic enzymes of cultured fish species into a semi-intensive pond culture system,reared with Catla catla(catla),Labeo rohita(rahu),Clarias batracus(magur)and Anabas testudineus(climbing perch)for 90 days in two seasons.Choline was added directly into the pond water periodically throughout the experimental tenure.The water quality parameters of each experimental pond were monitored and were analyzed in 15 days interval throughout the experimental tenure in both the seasons.Results were compared with treatment as choline-fed and control as non-choline-fed conditions during breeding(June-Aug.)and dry(Nov.-Jan.)seasons.The metabolic enzymes,viz.,LDH(Lactate dehydrogenase),MDH(Malate dehydrogenase),and G6PDH(Glucose-6-phosphate dehydrogenase)activities in the muscle,liver,and AchE(Acetylcholine esterase)activity in the brain and muscle revealed maximum significantly(p<0.01),but ALT(Alanine aminotransferase)and AST(Aspartate aminotransferase)activity showed significant(p<0.01)depletion in the muscle and liver in treatment-breeding(TB)condition.The fishes under treatment-dry(TD)condition presented significant(p<0.01)higher elevation in HK(Hexokinase)activity in the muscle and liver.Additionally,the result of principal component analysis(PCA)depicted the positive as well as in some cases a negative correlation among the enzymatic activities both in dry and breeding seasons.So,it can be inferred that choline enrichment in fishes can substantiate the well nutritionally balanced food-flesh for consumption under this farm culture and the choline behaved as a positive contaminant into the pond eco-system under the semi-intensive culture condition.
基金supported by a Discovery grant from the Natural Sciences and Engineering Research Council (NSERC) of Canada (Grant No. 6793)a grant from the Heart and Stroke Foundation of Canada (Grant No. G-14-0005874) to KBS. KBS holds the Canada Research Chair in Molecular Physiology
文摘The use of daily torpor and/or of multi-day torpor bouts during a hibernation season are energy-saving survival strategies that have been well-studied for many years,particularly for small mammals living in seasonally-cold environments.Both phenomena are characterized by a regulated suppression of metabolic rate,
