Establishing intraspecific breeding and hybridization programs and determining genetic variability are two important issues for aquaculture. However, interspecific hybridization to improve growth and feeding efficienc...Establishing intraspecific breeding and hybridization programs and determining genetic variability are two important issues for aquaculture. However, interspecific hybridization to improve growth and feeding efficiency is limited. For this purpose, the embryonic and larval development of reciprocal crosses of Clarias gariepinus (Burchell, 1822) and Clarias jaensis (Boulenger, 1909) were studied under laboratory conditions. The fertilization rate varied from 63.33% to 92%, while the hatching rate ranged from 55.68% to 76% with the highest value in hybrids ♀Cg × ♂Cj. Crosses between ♀Cj × ♂Cj, ♀Cg × ♂Cj and ♀Cj × ♂Cg had embryonic stages similar to those of the pure sib ♀Cg x ♂Cg. All crosses, however, had different timing for the various embryological stages. Hatching occurred at 32 h 15 min and 38 h for ♀Cj × ♂Cj and ♀Cj × ♂Cg, and 23 h and 23 h 30 min, respectively, for ♀Cg × ♂Cg and ♀Cg × ♂Cj. However, both crosses produced viable larvae until the first external feeding. The external morphological features of the larvae were completely formed by the 10th day after hatching. The body forms of the crosses at this time were indistinguishable from the pure sib. This study thus laid the groundwork for further comparative studies on hybrid performance and characterization.展开更多
Fishmeal is the most preferred source of protein in aquafeeds, but it is expensive and scarce. Hence, Achatina fulica meat meal (AFM), which is much less preferred for human consumption out of three species of African...Fishmeal is the most preferred source of protein in aquafeeds, but it is expensive and scarce. Hence, Achatina fulica meat meal (AFM), which is much less preferred for human consumption out of three species of African giant land snails, was tested as a fishmeal substitute for Clarias gariepinus growth. Five iso-nitrogenous and iso-calorific diets were formulated, in which AFM substituted fish meal at 0% (control or Diet A), 25% (Diet B), 50% (Diet C), 75% (Diet D) and 100% (Diet E). These dietary treatments were each replicated thrice in a completely randomized design experiment, using 36-L plastic tanks in which the fish were fed daily rations corresponding to 5% of their body weight, for 8 weeks. Water quality parameters in the tanks were monitored. Proximate analyses were conducted on the fish meal, snail meal and experimental diets before the feeding trials. Cost-benefit analysis of the different diets was performed. The crude protein content of AFM (69.18%) was significantly higher than that of fish meal (55.81%). There was no significant difference (P > 0.05) in the mean weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio and survival rate in fish fed Diet A and Diet B. The best protein efficiency ratio (0.77) was recorded in fish fed Diet B. Furthermore, the survival rate of fish increased with increased levels of AFM substitution. Water quality parameters were within a suitable range for tropical fish culture, indicating that the AFM did not pollute the water. The fish fed 25% AFM diet significantly (P Clarias gariepinus diets at a 25% substitution level. The aquaculture industry can thus exploit the availability of this feed resource.展开更多
This study focused on the supplementation of four-sided spice fruit powder (Tetrapleura tetraptera) on some zootechnical performances of juveniles of Clarias gariepinus and was carried out from February 14 to July 20 ...This study focused on the supplementation of four-sided spice fruit powder (Tetrapleura tetraptera) on some zootechnical performances of juveniles of Clarias gariepinus and was carried out from February 14 to July 20 at the Massoma Fish Farm of Bojongo Mbeidi located in the Littoral Region, Department of Wouri, Douala IV district. The farm benefits from a climate favorable to aquaculture activity. For this purpose, five (5) treatments were tested including T<sub>0+</sub> (imported feed), T<sub>0-</sub>, T<sub>0.3</sub>, T<sub>0.4</sub>, and T<sub>0.5</sub> respectively for the treatments with 0% supplemented food;0.3%;0.4% and 0.5% of Tetrapleura tetraptera powder. A total of 450 Clarias gariepinus fry with an initial average weight of 7 ± 1.5 g, were distributed in happas of 0.49 m<sup>2</sup> each placed in Triplicate in a completely randomized device. Four isoprotein foods with 38% crude protein were formulated to feed these fry at 7% of their biomass per day for 15 days then to their fullness until the end of the experiment. Intermediate fishing was carried out every fortnight. 75 days later, the results recorded show that the highest average survival rate (96.44% ± 3.5%) was recorded with the subjects fed feed supplemented with 0.4% T. tetraptera powder. The average weight (120.93 ± 67.20), weight gain (113.93 ± 67.20), specific growth rate (3.64 ± 0.79% g/d) and total lengths and standard (26.43 ± 1.9 and 23.66 ± 1.76) the highest were recorded with the T<sub>0+</sub> treatment (imported feed). The highest conditioning factor K (2.14 ± 0.15) was recorded with the treatment supplemented with 0.4% T. tetraptera. The lowest conversion ratio (1.28) was recorded with the treatment fed with imported blue crown food (T<sub>0+</sub>). Furthermore, the lowest production cost was recorded with the treatment supplemented with 0.4% T. tetraptera. It appears from this study that the juveniles of C. gariepinus better value the feed substituted with 0.4% of the powder of four sides (Tetrapleura tetraptera).展开更多
Water quality of the river Nile and trace elements of the water, sediments and fish tissues were investigated in the current work. Eighteen different sampling points were selected along the whole course of the River N...Water quality of the river Nile and trace elements of the water, sediments and fish tissues were investigated in the current work. Eighteen different sampling points were selected along the whole course of the River Nile from its spring at Aswan to its estuaries at Rosetta and Damietta. Higher mean value of conductivity, alkalinity, chemical oxygen demand (COD), total organic carbon (TOC), ammonia (NH3), nitrate (NO3), total solid (TS), sulphate (SO4), chloride (Cl), orthophosphate were recorded in the water of Damietta and Rosetta branches comparing to other sites. Also trace metals in the water, sediments and tissues of Clarias gariepinus increased significantly (P Fe > Cu > Pb > Mn > Cr> Cd > Hg. In the gill tissues theses metals were accumulated in the following order Fe > Zn > Mn > Pb > Cr > Cu > Cd> Hg. The low accumulation of metals in muscle may be due to lack of binding affinity of these metals with the proteins of muscle. This is particularly important because muscles contribute the greatest mass of the flesh that is consumed as food.展开更多
Objective:To evaluate the efficacy of dietary doses of garlic(Allium sativum L.) peel on the hematological and disease resistance of African catfish[Glorias gariepinus(C.gariepinus)] fingerlings against the infections...Objective:To evaluate the efficacy of dietary doses of garlic(Allium sativum L.) peel on the hematological and disease resistance of African catfish[Glorias gariepinus(C.gariepinus)] fingerlings against the infections caused by opportunistic bacterial pathogen Aeromonas hydrophila.Methods:Powdered garlic peel was incorporated into the diets at(0%,0.5%,1.0% and 1.5%) and fed to catfish fingerlings for 20 days.After the feeding trial,biochemical(serum total protein,albumin and globulin),hematological parameters(white blood cells and red blood cells) of the fish were examined.Fish were challenged with Aeromona hydrophila(A.hydrophila) after 20 days of post feeding and percentage mortalities were recorded up to 10 days after post challenge.Results:Enhanced serum protein,albumin and globulin in fish fed with all the dosages of garlic peel when compared to control group.Significantly highest red blood cell and white blood cell counts were recorded in garlic peel incorporated diet fed groups compared to control group.The results also demonstrate that low survival rate(55.5±11.0)%in control groups and significantly higher survival rates were recorded in all the garlic peel fed groups after challenging with A.hydrophila.However no significant impact was noticed with regard to body weight gain,specific growth rate and food conversion ratio of fish fed with different levels of garlic peel inclusion and control group.Conclusions:These results indicate that garlic peel enhances the hematological parameters even at a low level(0.5%) incorporation and makes C. gariepinus highly immunopotent and more resistant to infection by A.hydrophila.展开更多
Fingerlings of African catfish,Clarias gariepinus [mean total length,(7.0±1.0) cm SD;mean weight,(3.0±0.7) g SD] were exposed to acute concentrations of amine salt of 2,4-D(0,50,200,250,350,and 400 mg/L) to ...Fingerlings of African catfish,Clarias gariepinus [mean total length,(7.0±1.0) cm SD;mean weight,(3.0±0.7) g SD] were exposed to acute concentrations of amine salt of 2,4-D(0,50,200,250,350,and 400 mg/L) to determine the behavioural responses and mortality.When raised in aquaria the fish became hyperactive.The beat frequencies(opercular and tail beat frequency per minute,OBF and TBF) of the exposed fish declined with increase in the exposure duration and concentration,but the reverse was the case with percent mortality.These variables signifi cantly differed at both the exposure duration and concentration of the toxicant(P<0.05).Anova of the linear regression between variables-OBF,TBF and mortality on exposure duration indicated a strong positive relationship(P<0.001) with the entire variables except mortality and exposure duration.OBF and TBF were inversely correlated with exposure duration(r=-0.99;P<0.05).The 96 h lethal concentration was 165.36(133.29～190.51,C.L.) mg/L and the median lethal time at the highest concentration was 20.41(11.87～27.46) h.The results from this study revealed that 2,4-D was very toxic to C.gariepinus under laboratory conditions and its application should therefore,be restricted in the field.展开更多
The response of catfish fed differently timed wet-heat-treated sesame seedmeal was evaluated in the diet of Clarias gariepinus using growth performance, nutrient utilisation and apparent digesti-bility coefficient as ...The response of catfish fed differently timed wet-heat-treated sesame seedmeal was evaluated in the diet of Clarias gariepinus using growth performance, nutrient utilisation and apparent digesti-bility coefficient as indices. Three batches of sesame seed, which were cooked for 10, 20 and 30 minutes, dried, milled, and mechanically defatted using locally made screw press. Each of these differently processed seedmeals was included in the diet of African catfish at varying replacement levels, 15, 30 and 45% with soybean meal. There was good growth performance and nutrient uti-lization by Clarias gariepinus fed with differently timed wet-heat-treated sesame seed that was not significantly different (p > 0.05) from fish fed control diet. More so, the apparent digestibility coef-ficient for organic matter, protein, energy, lipid, fibre, carbohydrate in Clarias gariepinus fed with differently timed wet-heat-treated sesame seedmeal based diets in this study were comparable with the results obtained for fish fed control diets.展开更多
The median lethal concentrations (LC50s) of aldrin, fenvalerate, captan and diazinon were determined for Clarias batrachus by trimmed Spearman-Karber method. The potency ratios of toxicity among them were analysed by ...The median lethal concentrations (LC50s) of aldrin, fenvalerate, captan and diazinon were determined for Clarias batrachus by trimmed Spearman-Karber method. The potency ratios of toxicity among them were analysed by parallel-line bioassay with quantal responses. The LC50s for 40 day of exposure of aldrin, fenvalerate, captan and diazinon were 0.00036,0.0094, 0.5473 and 2.4186 ppm respectively. These values were lower than those obtained for an exposure of 96 hour. It shows the greater toxicity of the pesticides in a long-term exposure. The relative toxic potency of aldrin fenvalerate, captan and diazinon was in a ratio of 6807:241:4:1 respectively. Thus the chemically different groups of pesticides exhibit an order of toxicity as aldrin > fenvalerate >captan > diazinon for the freshwater catfish, Clarias batrachus. It infers that the catfish is most sensitive to aldrin and least sensitive to diazinon. The comparison of the sensitivity of various species tested against these pesticidal chemicals has also been done to review the available information.展开更多
The experiment was conducted to evaluate the acute toxicity of aqueous extract of Adenium obesum stem bark in juveniles of Clarias gariepinus by assessing the hematological responses of the exposed groups compared to ...The experiment was conducted to evaluate the acute toxicity of aqueous extract of Adenium obesum stem bark in juveniles of Clarias gariepinus by assessing the hematological responses of the exposed groups compared to the control in a static non-renewal bioassay for 96 hours. The fishes (N = 180, mean weight and length 21.48 ± 3.32 g and 11.37 ± 1.23 cm) respectively were randomly distributed 10 (ten) fishes per group in triplicates constituting six experimental groups as follows;G1 (Control), G2 (6.5 mg/l), G3 (7.8 mg/l), G4 (8.5 mg/l), G5 (9.5 mg/l) and G6 (11.5 mg/l). Red blood cell (RBC) count, packed cell volume (PCV) and hemoglobin concentration were decreased significantly (P < 0.05) as opposed to the significant (P < 0.05) increase in total white blood cell count (TWBC). Thus the study concludes that aqueous extract of Adenium obesum stem bark is toxic to erythrocytes while a converse adaptive response in the white blood cells.展开更多
A twelve week experiment was conducted to compare the effects of diets with plant-based and animal-based ingredients on growth and gonad development of Clarias gariepinus. One hundred and 12 sub-adult C. gariepinus wi...A twelve week experiment was conducted to compare the effects of diets with plant-based and animal-based ingredients on growth and gonad development of Clarias gariepinus. One hundred and 12 sub-adult C. gariepinus with an average weight of 205 ×5.09 g, were stocked in six concrete tanks （9 × 4 × 2 m3） containing 20 fish each. Experiment had 3 replicates and animals fed daily at 5% body weights. There was no significant difference （P 〈 0.05） in proximate compositions of the two experimental feeds and controls. Fecundity, gonad weight and gonasomatic index were higher in fish fed diet 13 than A and C. Similarly, growth indices were higher in fish fed diet B than in A and C. Histology of gonads showed a faster development of oocytes of eggs in fish fed animal-based ingredients than plant-based and combined plant and animal diets. Although there were slight differences in growth parameters and gonad development in favor of feed with animal-based ingredients, plant-based feed compared favorably in the growth and gonad development of C. gariepinus. Plant-based ingredients are recommended on the basis of affordability and availability as substitute for animal-based ingredients in C. gariepinus feed.展开更多
Quantitative variations in parasites were investigated with respect to sex and size of Clarias gariepinus, season and localities sampled. Parasitic infection in male and female fish was not significantly different;pre...Quantitative variations in parasites were investigated with respect to sex and size of Clarias gariepinus, season and localities sampled. Parasitic infection in male and female fish was not significantly different;prevalence (Man-Whitney paired sample test, U = 135.5, p = 0.7697), mean intensity (U = 136, p = 0.7829). Based on Kruskal-Wallis test analysis, the prevalence and mean intensity of five parasite species varied significantly among the three localities sampled. Adult parasites in Clarias gariepinus showed high abundance during the dry season while the larval forms showed high abundance in the wet season. In most of the parasite species analyzed the abundance varied significantly with host size. The abundance of Dolops ranarum, Paracamallanus cyatopharynx and Eumasenia bangweulensis for instance, increased with fish size, while that of Diplostomum mashonense, Tylodelphys species, Astiotrema reniferum, piscicolid leeches and Monobothrioides woodlandi increased initially but decreased as fish length reached 31 - 40 cm. Total parasite burden increased in fish of 20 - 40 cm standard length. Generally, most parasites were highly overdispersed and the negative binomial model described their distribution.展开更多
Specimens of Clarias gariepinus were treated with lethal(70,75,80,85,90,and 95 mg/L) and sub-lethal concentrations(8,12 and 16 mg/L) of uranyl acetate,a low-radiotoxicity uranium salt. The LC 50 value was registered a...Specimens of Clarias gariepinus were treated with lethal(70,75,80,85,90,and 95 mg/L) and sub-lethal concentrations(8,12 and 16 mg/L) of uranyl acetate,a low-radiotoxicity uranium salt. The LC 50 value was registered as 81.45 mg/L. The protein and glycogen concentrations in liver and muscles were decreased in the fish exposed to sub-lethal concentrations. The red blood cell(RBC) and white blood cell(WBC) counts,haemoglobin(Hb) concentration and haematocrit(Hct) values were decreased. Different blood indices like mean corpuscular volume(MCV),mean corpuscular haemoglobin(MCH) and mean corpuscular haemoglobin concentration(MCHC) were negatively affected. Level of plasma glucose was elevated whereas protein was decreased. The level of calcium concentration(Ca) was declined in the blood of exposed fish whereas magnesium(Mg) remains unchanged. The activity level of glutamic-oxaloacetic transaminase(GOT) and glutamic-pyruvic transaminase(GPT) was elevated in exposed fish. These effects were more pronounced in the last period of exposure and in higher concentrations. Results of the present study indicate that uranyl acetate has adverse effects on C larias gariepinus and causes changes in the biochemical and hematological parameters of the fish.展开更多
The African catfish, Clarias gariepinus, is generally considered to be one of the most important tropical catfish species for aquaculture purposes. Parasitological investigation was performed in two hundred naturally ...The African catfish, Clarias gariepinus, is generally considered to be one of the most important tropical catfish species for aquaculture purposes. Parasitological investigation was performed in two hundred naturally collected fish samples during the period of February to December 2014. The prevalence of gastrointestinal helminth parasites infecting C. gariepinus was investigated. A total of 249 helminth parasites belonging to four genera were recovered from 130 (65%) examined fish samples. They were digenea Orientocreadium batrachoides, cestode Polyonchobothrium clariae, and nematode Procamallanus laevionchus and Camallanus polypteri. Majority of the recorded parasites were found in the intestine. Female fish samples had higher prevalence rate 72 (90%) than males 58 (48.33%), and there was no significant difference (P > 0.05) in infestation rate between the two sexes. The relationship of host size (weight/length) and parasite infection showed that there was no significant difference in the parasitic infection among three classes, although fish of larger sizes had more infections. In addition, this study determines the effect of fish age on the prevalence and intensity of gastrointestinal parasites.展开更多
The study was carried out using 328 Clarias gariepinus specimens over a period of two years, from Oba reservoir (08°3'N to 08°12'N and 004°6'E to 004°12'E) Ogbomoso,...The study was carried out using 328 Clarias gariepinus specimens over a period of two years, from Oba reservoir (08°3'N to 08°12'N and 004°6'E to 004°12'E) Ogbomoso, Oyo State, Nigeria. Standard methods were used to determine length-weight relationship, condition factor, and enteroparasitic infestation of the fish in the reservoir. Generally, Fish growth was positively allometric, while infested male and female fishes had negative allometric growth. The general well-being of the male fish was better than that of the female fish. Smaller sized fishes were better adapted to the ecological conditions of the reservoir than the bigger fishes. Parasites recovered were two Nematodes (Procamallanus laevionchus, Paracamallanus cyathopharynx), three Cestodes (Anomotaenia sp. Monobothrium sp., Polyonchobothrium clariae), and one Acanthocephalan (Neoechinorhynchus rutili). Sex ratio was 1.3:1 (male: female). Parasitic prevalence and intensity in the fish were sex and season dependent. The effect of enteroparasites in the life of infested C. gariepinus was found to probably be a major factor responsible for the low percentage of good fit to the line of regression (R2) in females. Infestation also led to loss of weight in infested fishes and this affected morphometric values in which body weight was an index.展开更多
The Samandeni reservoir in Burkina Faso, impounded in 2017, hosts a significant diversity of fish, including the Clariidae family. The fish stocks have been exploited since 2019, when the reservoir was opened to fishe...The Samandeni reservoir in Burkina Faso, impounded in 2017, hosts a significant diversity of fish, including the Clariidae family. The fish stocks have been exploited since 2019, when the reservoir was opened to fishermen. However, no assessment of the status of these stocks has been conducted. The present study focused on the dynamics of Clarias anguillaris exploitation in order to have reliable information that can contribute to the planning of its sustainable exploitation. Length-frequency data on 323 individuals were sampled from commercial catches from March 2021 to February 2022. The growth parameters were determined using ELEFAN method and the stock assessment was done using the Bayesian Length-Based Biomass (LBB) method. The growth analysis showed isometry for both male and female fishes with allometric coefficient value of 3.03, 3.01 and 3.17 respectively for mixed sexes, male and female. Estimates values (0.6 and 0.4) of the growth oscillation intensity indicate the existence of seasonal growth. The relative biomass (B/B<sub>0</sub>) estimated for C. anguillaris was less than the relative biomass that produces the maximum sustainable yield (B<sub>MSY</sub>/B<sub>0</sub>) indicating biomass overfishing. In addition, the length at first capture was less than the optimal length at first capture indicating a growth overfishing status. Therefore, it would be desirable to increase the mesh size of the fishing gear so that juveniles are not caught, which will ensure an ecological sustainability of the exploitation of the Clariidae.展开更多
Seasonal variations in serological profiles and growth status of farmed and wild Clarias gariepinus were investigated. Serological profiles of Clarias gariepinus can be an effective tool for proper monitoring of stres...Seasonal variations in serological profiles and growth status of farmed and wild Clarias gariepinus were investigated. Serological profiles of Clarias gariepinus can be an effective tool for proper monitoring of stress induced by management practices in intensive fish culture, which may elicit devastating effect on fish. Spectrophotometry procedures were used to analyze serum parameters of Clarias gariepinus. No different seasonal patterns were observed for mean values of albumin, total protein, urea, cholesterol, glucose and alanine amino-transferase. However, aspartate amino-transferase showed different seasonal pattern. Levels of cholesterol and alanine amino-transferase were highly significant in farmed and wild fish, separately. Juvenile fish had high level of urea irrespective of season. Seasonal variations in water quality parameters were observed except for pH which had no seasonal pattern. The growth exponential shows b-values between -0.048 and 7.434 for Clarias gariepinus. Adult female and juvenile fish from the wild had the highest b-value and the least b-value, separately. In this study, b-values were higher in the wild fish than the farmed fish. The condition factor for Clarias gariepinus ranged from 0.422 to 0.698, and was observed to be high in juvenile fish. With a condition factor less than 1, fish may not be doing well, probably due to environmental stress. Some serological parameters varied according to season and environment of fish. Thus, serological profile of fish is an effective and sensitive tool to monitor fish response to stress factors in the environment.展开更多
A research was conducted to assess the effects of three different drying techniques, namely open sun drying （OSD）, solar dryers （SD） and solar tent dryers （STD）. Data on physical characteristics such as weight, ...A research was conducted to assess the effects of three different drying techniques, namely open sun drying （OSD）, solar dryers （SD） and solar tent dryers （STD）. Data on physical characteristics such as weight, total length and standard length were recorded and proximate composition of the fish sample Clarias gariepinus （Burchell, 1822） was carried out before, during and after drying to assess changes on physical characteristics and nutrient composition at different level. After drying, the samples were subjected to storage for eight weeks. The result obtained shows that there was no significant （P 〉 0.01） difference in the drying weight of the fish samples between the direct SD and the STD. However, for the total and standard length there was significant （P 〈 0.01） difference in the drying techniques, but no significant difference （P 〉 0.05） in the drying period. There was no significant （P 〉 0.05） difference on the physical parameters, storage period, proximate composition of both direct SD and STD and the drying period, respectively. Therefore, direct SD can be substituted with the STD without altering the quality of the product.展开更多
文摘Establishing intraspecific breeding and hybridization programs and determining genetic variability are two important issues for aquaculture. However, interspecific hybridization to improve growth and feeding efficiency is limited. For this purpose, the embryonic and larval development of reciprocal crosses of Clarias gariepinus (Burchell, 1822) and Clarias jaensis (Boulenger, 1909) were studied under laboratory conditions. The fertilization rate varied from 63.33% to 92%, while the hatching rate ranged from 55.68% to 76% with the highest value in hybrids ♀Cg × ♂Cj. Crosses between ♀Cj × ♂Cj, ♀Cg × ♂Cj and ♀Cj × ♂Cg had embryonic stages similar to those of the pure sib ♀Cg x ♂Cg. All crosses, however, had different timing for the various embryological stages. Hatching occurred at 32 h 15 min and 38 h for ♀Cj × ♂Cj and ♀Cj × ♂Cg, and 23 h and 23 h 30 min, respectively, for ♀Cg × ♂Cg and ♀Cg × ♂Cj. However, both crosses produced viable larvae until the first external feeding. The external morphological features of the larvae were completely formed by the 10th day after hatching. The body forms of the crosses at this time were indistinguishable from the pure sib. This study thus laid the groundwork for further comparative studies on hybrid performance and characterization.
文摘Fishmeal is the most preferred source of protein in aquafeeds, but it is expensive and scarce. Hence, Achatina fulica meat meal (AFM), which is much less preferred for human consumption out of three species of African giant land snails, was tested as a fishmeal substitute for Clarias gariepinus growth. Five iso-nitrogenous and iso-calorific diets were formulated, in which AFM substituted fish meal at 0% (control or Diet A), 25% (Diet B), 50% (Diet C), 75% (Diet D) and 100% (Diet E). These dietary treatments were each replicated thrice in a completely randomized design experiment, using 36-L plastic tanks in which the fish were fed daily rations corresponding to 5% of their body weight, for 8 weeks. Water quality parameters in the tanks were monitored. Proximate analyses were conducted on the fish meal, snail meal and experimental diets before the feeding trials. Cost-benefit analysis of the different diets was performed. The crude protein content of AFM (69.18%) was significantly higher than that of fish meal (55.81%). There was no significant difference (P > 0.05) in the mean weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio and survival rate in fish fed Diet A and Diet B. The best protein efficiency ratio (0.77) was recorded in fish fed Diet B. Furthermore, the survival rate of fish increased with increased levels of AFM substitution. Water quality parameters were within a suitable range for tropical fish culture, indicating that the AFM did not pollute the water. The fish fed 25% AFM diet significantly (P Clarias gariepinus diets at a 25% substitution level. The aquaculture industry can thus exploit the availability of this feed resource.
文摘This study focused on the supplementation of four-sided spice fruit powder (Tetrapleura tetraptera) on some zootechnical performances of juveniles of Clarias gariepinus and was carried out from February 14 to July 20 at the Massoma Fish Farm of Bojongo Mbeidi located in the Littoral Region, Department of Wouri, Douala IV district. The farm benefits from a climate favorable to aquaculture activity. For this purpose, five (5) treatments were tested including T<sub>0+</sub> (imported feed), T<sub>0-</sub>, T<sub>0.3</sub>, T<sub>0.4</sub>, and T<sub>0.5</sub> respectively for the treatments with 0% supplemented food;0.3%;0.4% and 0.5% of Tetrapleura tetraptera powder. A total of 450 Clarias gariepinus fry with an initial average weight of 7 ± 1.5 g, were distributed in happas of 0.49 m<sup>2</sup> each placed in Triplicate in a completely randomized device. Four isoprotein foods with 38% crude protein were formulated to feed these fry at 7% of their biomass per day for 15 days then to their fullness until the end of the experiment. Intermediate fishing was carried out every fortnight. 75 days later, the results recorded show that the highest average survival rate (96.44% ± 3.5%) was recorded with the subjects fed feed supplemented with 0.4% T. tetraptera powder. The average weight (120.93 ± 67.20), weight gain (113.93 ± 67.20), specific growth rate (3.64 ± 0.79% g/d) and total lengths and standard (26.43 ± 1.9 and 23.66 ± 1.76) the highest were recorded with the T<sub>0+</sub> treatment (imported feed). The highest conditioning factor K (2.14 ± 0.15) was recorded with the treatment supplemented with 0.4% T. tetraptera. The lowest conversion ratio (1.28) was recorded with the treatment fed with imported blue crown food (T<sub>0+</sub>). Furthermore, the lowest production cost was recorded with the treatment supplemented with 0.4% T. tetraptera. It appears from this study that the juveniles of C. gariepinus better value the feed substituted with 0.4% of the powder of four sides (Tetrapleura tetraptera).
文摘Water quality of the river Nile and trace elements of the water, sediments and fish tissues were investigated in the current work. Eighteen different sampling points were selected along the whole course of the River Nile from its spring at Aswan to its estuaries at Rosetta and Damietta. Higher mean value of conductivity, alkalinity, chemical oxygen demand (COD), total organic carbon (TOC), ammonia (NH3), nitrate (NO3), total solid (TS), sulphate (SO4), chloride (Cl), orthophosphate were recorded in the water of Damietta and Rosetta branches comparing to other sites. Also trace metals in the water, sediments and tissues of Clarias gariepinus increased significantly (P Fe > Cu > Pb > Mn > Cr> Cd > Hg. In the gill tissues theses metals were accumulated in the following order Fe > Zn > Mn > Pb > Cr > Cu > Cd> Hg. The low accumulation of metals in muscle may be due to lack of binding affinity of these metals with the proteins of muscle. This is particularly important because muscles contribute the greatest mass of the flesh that is consumed as food.
文摘Objective:To evaluate the efficacy of dietary doses of garlic(Allium sativum L.) peel on the hematological and disease resistance of African catfish[Glorias gariepinus(C.gariepinus)] fingerlings against the infections caused by opportunistic bacterial pathogen Aeromonas hydrophila.Methods:Powdered garlic peel was incorporated into the diets at(0%,0.5%,1.0% and 1.5%) and fed to catfish fingerlings for 20 days.After the feeding trial,biochemical(serum total protein,albumin and globulin),hematological parameters(white blood cells and red blood cells) of the fish were examined.Fish were challenged with Aeromona hydrophila(A.hydrophila) after 20 days of post feeding and percentage mortalities were recorded up to 10 days after post challenge.Results:Enhanced serum protein,albumin and globulin in fish fed with all the dosages of garlic peel when compared to control group.Significantly highest red blood cell and white blood cell counts were recorded in garlic peel incorporated diet fed groups compared to control group.The results also demonstrate that low survival rate(55.5±11.0)%in control groups and significantly higher survival rates were recorded in all the garlic peel fed groups after challenging with A.hydrophila.However no significant impact was noticed with regard to body weight gain,specific growth rate and food conversion ratio of fish fed with different levels of garlic peel inclusion and control group.Conclusions:These results indicate that garlic peel enhances the hematological parameters even at a low level(0.5%) incorporation and makes C. gariepinus highly immunopotent and more resistant to infection by A.hydrophila.
文摘Fingerlings of African catfish,Clarias gariepinus [mean total length,(7.0±1.0) cm SD;mean weight,(3.0±0.7) g SD] were exposed to acute concentrations of amine salt of 2,4-D(0,50,200,250,350,and 400 mg/L) to determine the behavioural responses and mortality.When raised in aquaria the fish became hyperactive.The beat frequencies(opercular and tail beat frequency per minute,OBF and TBF) of the exposed fish declined with increase in the exposure duration and concentration,but the reverse was the case with percent mortality.These variables signifi cantly differed at both the exposure duration and concentration of the toxicant(P<0.05).Anova of the linear regression between variables-OBF,TBF and mortality on exposure duration indicated a strong positive relationship(P<0.001) with the entire variables except mortality and exposure duration.OBF and TBF were inversely correlated with exposure duration(r=-0.99;P<0.05).The 96 h lethal concentration was 165.36(133.29～190.51,C.L.) mg/L and the median lethal time at the highest concentration was 20.41(11.87～27.46) h.The results from this study revealed that 2,4-D was very toxic to C.gariepinus under laboratory conditions and its application should therefore,be restricted in the field.
文摘The response of catfish fed differently timed wet-heat-treated sesame seedmeal was evaluated in the diet of Clarias gariepinus using growth performance, nutrient utilisation and apparent digesti-bility coefficient as indices. Three batches of sesame seed, which were cooked for 10, 20 and 30 minutes, dried, milled, and mechanically defatted using locally made screw press. Each of these differently processed seedmeals was included in the diet of African catfish at varying replacement levels, 15, 30 and 45% with soybean meal. There was good growth performance and nutrient uti-lization by Clarias gariepinus fed with differently timed wet-heat-treated sesame seed that was not significantly different (p > 0.05) from fish fed control diet. More so, the apparent digestibility coef-ficient for organic matter, protein, energy, lipid, fibre, carbohydrate in Clarias gariepinus fed with differently timed wet-heat-treated sesame seedmeal based diets in this study were comparable with the results obtained for fish fed control diets.
文摘The median lethal concentrations (LC50s) of aldrin, fenvalerate, captan and diazinon were determined for Clarias batrachus by trimmed Spearman-Karber method. The potency ratios of toxicity among them were analysed by parallel-line bioassay with quantal responses. The LC50s for 40 day of exposure of aldrin, fenvalerate, captan and diazinon were 0.00036,0.0094, 0.5473 and 2.4186 ppm respectively. These values were lower than those obtained for an exposure of 96 hour. It shows the greater toxicity of the pesticides in a long-term exposure. The relative toxic potency of aldrin fenvalerate, captan and diazinon was in a ratio of 6807:241:4:1 respectively. Thus the chemically different groups of pesticides exhibit an order of toxicity as aldrin > fenvalerate >captan > diazinon for the freshwater catfish, Clarias batrachus. It infers that the catfish is most sensitive to aldrin and least sensitive to diazinon. The comparison of the sensitivity of various species tested against these pesticidal chemicals has also been done to review the available information.
文摘The experiment was conducted to evaluate the acute toxicity of aqueous extract of Adenium obesum stem bark in juveniles of Clarias gariepinus by assessing the hematological responses of the exposed groups compared to the control in a static non-renewal bioassay for 96 hours. The fishes (N = 180, mean weight and length 21.48 ± 3.32 g and 11.37 ± 1.23 cm) respectively were randomly distributed 10 (ten) fishes per group in triplicates constituting six experimental groups as follows;G1 (Control), G2 (6.5 mg/l), G3 (7.8 mg/l), G4 (8.5 mg/l), G5 (9.5 mg/l) and G6 (11.5 mg/l). Red blood cell (RBC) count, packed cell volume (PCV) and hemoglobin concentration were decreased significantly (P < 0.05) as opposed to the significant (P < 0.05) increase in total white blood cell count (TWBC). Thus the study concludes that aqueous extract of Adenium obesum stem bark is toxic to erythrocytes while a converse adaptive response in the white blood cells.
文摘A twelve week experiment was conducted to compare the effects of diets with plant-based and animal-based ingredients on growth and gonad development of Clarias gariepinus. One hundred and 12 sub-adult C. gariepinus with an average weight of 205 ×5.09 g, were stocked in six concrete tanks （9 × 4 × 2 m3） containing 20 fish each. Experiment had 3 replicates and animals fed daily at 5% body weights. There was no significant difference （P 〈 0.05） in proximate compositions of the two experimental feeds and controls. Fecundity, gonad weight and gonasomatic index were higher in fish fed diet 13 than A and C. Similarly, growth indices were higher in fish fed diet B than in A and C. Histology of gonads showed a faster development of oocytes of eggs in fish fed animal-based ingredients than plant-based and combined plant and animal diets. Although there were slight differences in growth parameters and gonad development in favor of feed with animal-based ingredients, plant-based feed compared favorably in the growth and gonad development of C. gariepinus. Plant-based ingredients are recommended on the basis of affordability and availability as substitute for animal-based ingredients in C. gariepinus feed.
文摘Quantitative variations in parasites were investigated with respect to sex and size of Clarias gariepinus, season and localities sampled. Parasitic infection in male and female fish was not significantly different;prevalence (Man-Whitney paired sample test, U = 135.5, p = 0.7697), mean intensity (U = 136, p = 0.7829). Based on Kruskal-Wallis test analysis, the prevalence and mean intensity of five parasite species varied significantly among the three localities sampled. Adult parasites in Clarias gariepinus showed high abundance during the dry season while the larval forms showed high abundance in the wet season. In most of the parasite species analyzed the abundance varied significantly with host size. The abundance of Dolops ranarum, Paracamallanus cyatopharynx and Eumasenia bangweulensis for instance, increased with fish size, while that of Diplostomum mashonense, Tylodelphys species, Astiotrema reniferum, piscicolid leeches and Monobothrioides woodlandi increased initially but decreased as fish length reached 31 - 40 cm. Total parasite burden increased in fish of 20 - 40 cm standard length. Generally, most parasites were highly overdispersed and the negative binomial model described their distribution.
基金Supported by the Deanship of Scientific Research at King Saud University(No.PRG-1436-011)
文摘Specimens of Clarias gariepinus were treated with lethal(70,75,80,85,90,and 95 mg/L) and sub-lethal concentrations(8,12 and 16 mg/L) of uranyl acetate,a low-radiotoxicity uranium salt. The LC 50 value was registered as 81.45 mg/L. The protein and glycogen concentrations in liver and muscles were decreased in the fish exposed to sub-lethal concentrations. The red blood cell(RBC) and white blood cell(WBC) counts,haemoglobin(Hb) concentration and haematocrit(Hct) values were decreased. Different blood indices like mean corpuscular volume(MCV),mean corpuscular haemoglobin(MCH) and mean corpuscular haemoglobin concentration(MCHC) were negatively affected. Level of plasma glucose was elevated whereas protein was decreased. The level of calcium concentration(Ca) was declined in the blood of exposed fish whereas magnesium(Mg) remains unchanged. The activity level of glutamic-oxaloacetic transaminase(GOT) and glutamic-pyruvic transaminase(GPT) was elevated in exposed fish. These effects were more pronounced in the last period of exposure and in higher concentrations. Results of the present study indicate that uranyl acetate has adverse effects on C larias gariepinus and causes changes in the biochemical and hematological parameters of the fish.
文摘The African catfish, Clarias gariepinus, is generally considered to be one of the most important tropical catfish species for aquaculture purposes. Parasitological investigation was performed in two hundred naturally collected fish samples during the period of February to December 2014. The prevalence of gastrointestinal helminth parasites infecting C. gariepinus was investigated. A total of 249 helminth parasites belonging to four genera were recovered from 130 (65%) examined fish samples. They were digenea Orientocreadium batrachoides, cestode Polyonchobothrium clariae, and nematode Procamallanus laevionchus and Camallanus polypteri. Majority of the recorded parasites were found in the intestine. Female fish samples had higher prevalence rate 72 (90%) than males 58 (48.33%), and there was no significant difference (P > 0.05) in infestation rate between the two sexes. The relationship of host size (weight/length) and parasite infection showed that there was no significant difference in the parasitic infection among three classes, although fish of larger sizes had more infections. In addition, this study determines the effect of fish age on the prevalence and intensity of gastrointestinal parasites.
文摘The study was carried out using 328 Clarias gariepinus specimens over a period of two years, from Oba reservoir (08°3'N to 08°12'N and 004°6'E to 004°12'E) Ogbomoso, Oyo State, Nigeria. Standard methods were used to determine length-weight relationship, condition factor, and enteroparasitic infestation of the fish in the reservoir. Generally, Fish growth was positively allometric, while infested male and female fishes had negative allometric growth. The general well-being of the male fish was better than that of the female fish. Smaller sized fishes were better adapted to the ecological conditions of the reservoir than the bigger fishes. Parasites recovered were two Nematodes (Procamallanus laevionchus, Paracamallanus cyathopharynx), three Cestodes (Anomotaenia sp. Monobothrium sp., Polyonchobothrium clariae), and one Acanthocephalan (Neoechinorhynchus rutili). Sex ratio was 1.3:1 (male: female). Parasitic prevalence and intensity in the fish were sex and season dependent. The effect of enteroparasites in the life of infested C. gariepinus was found to probably be a major factor responsible for the low percentage of good fit to the line of regression (R2) in females. Infestation also led to loss of weight in infested fishes and this affected morphometric values in which body weight was an index.
文摘The Samandeni reservoir in Burkina Faso, impounded in 2017, hosts a significant diversity of fish, including the Clariidae family. The fish stocks have been exploited since 2019, when the reservoir was opened to fishermen. However, no assessment of the status of these stocks has been conducted. The present study focused on the dynamics of Clarias anguillaris exploitation in order to have reliable information that can contribute to the planning of its sustainable exploitation. Length-frequency data on 323 individuals were sampled from commercial catches from March 2021 to February 2022. The growth parameters were determined using ELEFAN method and the stock assessment was done using the Bayesian Length-Based Biomass (LBB) method. The growth analysis showed isometry for both male and female fishes with allometric coefficient value of 3.03, 3.01 and 3.17 respectively for mixed sexes, male and female. Estimates values (0.6 and 0.4) of the growth oscillation intensity indicate the existence of seasonal growth. The relative biomass (B/B<sub>0</sub>) estimated for C. anguillaris was less than the relative biomass that produces the maximum sustainable yield (B<sub>MSY</sub>/B<sub>0</sub>) indicating biomass overfishing. In addition, the length at first capture was less than the optimal length at first capture indicating a growth overfishing status. Therefore, it would be desirable to increase the mesh size of the fishing gear so that juveniles are not caught, which will ensure an ecological sustainability of the exploitation of the Clariidae.
文摘Seasonal variations in serological profiles and growth status of farmed and wild Clarias gariepinus were investigated. Serological profiles of Clarias gariepinus can be an effective tool for proper monitoring of stress induced by management practices in intensive fish culture, which may elicit devastating effect on fish. Spectrophotometry procedures were used to analyze serum parameters of Clarias gariepinus. No different seasonal patterns were observed for mean values of albumin, total protein, urea, cholesterol, glucose and alanine amino-transferase. However, aspartate amino-transferase showed different seasonal pattern. Levels of cholesterol and alanine amino-transferase were highly significant in farmed and wild fish, separately. Juvenile fish had high level of urea irrespective of season. Seasonal variations in water quality parameters were observed except for pH which had no seasonal pattern. The growth exponential shows b-values between -0.048 and 7.434 for Clarias gariepinus. Adult female and juvenile fish from the wild had the highest b-value and the least b-value, separately. In this study, b-values were higher in the wild fish than the farmed fish. The condition factor for Clarias gariepinus ranged from 0.422 to 0.698, and was observed to be high in juvenile fish. With a condition factor less than 1, fish may not be doing well, probably due to environmental stress. Some serological parameters varied according to season and environment of fish. Thus, serological profile of fish is an effective and sensitive tool to monitor fish response to stress factors in the environment.
文摘A research was conducted to assess the effects of three different drying techniques, namely open sun drying （OSD）, solar dryers （SD） and solar tent dryers （STD）. Data on physical characteristics such as weight, total length and standard length were recorded and proximate composition of the fish sample Clarias gariepinus （Burchell, 1822） was carried out before, during and after drying to assess changes on physical characteristics and nutrient composition at different level. After drying, the samples were subjected to storage for eight weeks. The result obtained shows that there was no significant （P 〉 0.01） difference in the drying weight of the fish samples between the direct SD and the STD. However, for the total and standard length there was significant （P 〈 0.01） difference in the drying techniques, but no significant difference （P 〉 0.05） in the drying period. There was no significant （P 〉 0.05） difference on the physical parameters, storage period, proximate composition of both direct SD and STD and the drying period, respectively. Therefore, direct SD can be substituted with the STD without altering the quality of the product.
