Background With the global expansion of aquaculture and the increasing demand for fish meal,identifying appropriate and sustainable alternative protein sources for aquafeeds has become essential.Single-cell protein(SC...Background With the global expansion of aquaculture and the increasing demand for fish meal,identifying appropriate and sustainable alternative protein sources for aquafeeds has become essential.Single-cell protein(SCP),derived from methanotrophic bacteria,presents a promising alternative by converting methane into protein,potentially addressing both the need for alternative protein sources and reducing industrial greenhouse gas emissions.This study aimed to evaluate the effects of different levels of SCP inclusion(0%,25%,50%,and 75%fish meal replacement)on the health,gene expression,and gut microbiome of yellowtail kingfish(YTK,Seriola lalandi)following a 35-day growth trial.Results The study found that SCP inclusion at the highest level of fishmeal replacement(75%)induced a mild inflammatory response in the hindgut of the fish.However,micromorphological assessments of the hindgut,serum biochemistry,and gene expression analyses revealed no significant detrimental effects from SCP replacement.Notably,there were indications of improved lipid digestibility with SCP.Furthermore,SCP inclusion significantly enhanced microbial richness and altered the composition of the gut microbiome,introducing beneficial bacterial taxa that may contribute to improved gut health and resilience.Conclusions This study highlights SCP as a viable and sustainable alternative to fish meal in YTK diets.The findings suggest that SCP can be included in YTK diets without adverse health effects at moderate levels and may even offer benefits in terms of lipid digestibility and gut microbiome diversity.These results contribute to the advancement of more sustainable aquaculture practices.展开更多
The dietary selenium (Se) requirement of yellowtail kingfish (Seriola lalandi) in normal and infected conditions was investigated. The fish were fed one of five experimental diets;a control un-supplemented diet (3.35 ...The dietary selenium (Se) requirement of yellowtail kingfish (Seriola lalandi) in normal and infected conditions was investigated. The fish were fed one of five experimental diets;a control un-supplemented diet (3.35 mg/kg Se) or diets supplemented with Se to provide 4.86, 5.38, 5.85 or 6.38 mg/kg Se. After feeding for 6 weeks, the fish were challenged by Vibrio anguillarum immersion and then observed for 4 weeks. Supplementation of Se had no effect on feed intake, feed conversion ratio and survival over 6 weeks of feeding;however, it significantly increased growth and Se content in muscle tissues. The optimal Se level for maximal growth of yellowtail kingfish estimated by second order regression was 5.56 mg/kg. Following the bacterial challenge, the immune-stimulating effects of Se were demonstrated in lysozyme and bactericidal activities, and there was a corresponding increase in survival and antibody response by supplementation of Se at ≥2 mg/kg (measured Se of ≥5.38 mg/kg). Under normal and infectious conditions, antioxidant capacity of fish measured as glutathione peroxidase activity increased by supplementation of Se. During post-challenge period, haematocrits were higher in the fish fed Se supplemented diets than the fish fed the control diet, while more macrophage aggregates were seen in the control group than in the others. Furthermore, there was evidence of myopathy in fish fed the diet without Se supplementation. Therefore, the results indicated that the optimal dietary Se requirement of yellowtail kingfish is 5.56 mg/kg.展开更多
This paper exemplifies a primary step towards eliciting primary and secondary stakeholders’ views on management issues pertaining to kingfish fishery in Oman, and potential options for effective management of the fis...This paper exemplifies a primary step towards eliciting primary and secondary stakeholders’ views on management issues pertaining to kingfish fishery in Oman, and potential options for effective management of the fishery using questionnaire surveys and focus group interviews. There was consensus from stakeholder groups which included fishers, fishery managers, and fishery scientists that the current stock condition is not biologically sustainable. It is found that fishing effort control and technical measures are preferred to catch control by both groups. The role of mass media and the traditional institution in communicating fisheries issues are found to be relatively minor. Although the overall rating on the comprehensiveness of the proposed plan is promising, there are significant differences between the two groups with regard to legislative arrangements (χ<sup>2</sup> = 24.793, p-value = 0.000), management goals (χ<sup>2</sup> = 16.206, p-value = 0.001), operational objectives (χ<sup>2</sup> = 19.884, p-value = 0.000), performance indicators (χ<sup>2</sup> = 15.524, p-value = 0.001), and measures (χ<sup>2</sup> = 13.483, p-value = 0.004). Policy implications of the key findings are discussed in both national and regional contexts. Management authorities can use these findings to design an appropriate plan of actions for achieving sustainability in this fishery.展开更多
Background: Water clarity may negatively influence rate of plunge diving and prey capture success of piscivorous plunge-diving birds, and therefore has implications for their conservation in polluted urban wetlands. W...Background: Water clarity may negatively influence rate of plunge diving and prey capture success of piscivorous plunge-diving birds, and therefore has implications for their conservation in polluted urban wetlands. We studied the relationship between water clarity and the abundance and prey capture success of Pied Kingfishers(Ceryle rudis) and Common Terns(Sterna hirundo) in two polluted coastal waters of south-east Ghana—the Weija Lake and Densu Delta Ramsar Site.Methods: On each wetland, data on abundance and prey capture success of plunge-divers were collected in four spatio-temporal quadrats of 100 m × 100 m and analysed with concurrent measurements of water quality parameters using GLM regression with Pearson's correlation coefficients.Results: Mean prey capture success of Pied Kingfishers(34.7 e two species responded differently to water clarity. The± 13.1%) and Common Terns(35.3 abundance of Common Terns was± 11.0%) were similar but th significantly higher in less transparent/more turbid water while that of Pied Kingfishers showed no significant relationship with turbidity and transparency. In contrast, the prey capture success of Common Terns was neither related to transparency nor turbidity, as opposed to that of Pied Kingfishers which was significantly higher in more turbid/less transparent waters. Correlations between capture success and bird abundance, as well as capture attempts were insignificant, suggesting that increased fish abundance associated with cloudy water may not necessarily promote higher abundance and capture success of foraging birds. Thus, when foraging in less transparent water, capture success may depend more on predator avoidance by fish prey than lower prey detectability of foraging birds.Conclusion: Within a gradient of 15–51 cm transparency studied, lower water clarity did not constrain prey capture success of Common Terns and Pied Kingfishers. Further studies on the foraging ecology of plunge-divers in coastal Ghana are however required to make firm conclusions on the relationship between water clarity and foraging birds and fish prey abundances, as well as capture success.展开更多
为提升chirplet变换(chirplet transform,CT)估算瞬时频率的精度,在CT基础上结合花斑翠鸟优化(pied kingfisher optimizer,PKO)和径向基移动最小二乘(radial basis function moving least squares,RBFMLS)算法提出了一种识别结构瞬时频...为提升chirplet变换(chirplet transform,CT)估算瞬时频率的精度,在CT基础上结合花斑翠鸟优化(pied kingfisher optimizer,PKO)和径向基移动最小二乘(radial basis function moving least squares,RBFMLS)算法提出了一种识别结构瞬时频率的新方法。该方法采用正定紧支径向基函数作为移动最小二乘近似的权函数,对CT的能量脊线进行估算,同时应用PKO对RBFMLS节点支撑半径和CT窗函数宽度进行优化。通过一组解析信号数值算例和一个时变拉索试验验证了所提方法的有效性。研究结果表明,该方法能有效改善信号分析的能量聚集性,提高瞬时频率的识别精度。展开更多
基金Fisheries Research Development Corporation,Grant/Award Number:2017-030.
文摘Background With the global expansion of aquaculture and the increasing demand for fish meal,identifying appropriate and sustainable alternative protein sources for aquafeeds has become essential.Single-cell protein(SCP),derived from methanotrophic bacteria,presents a promising alternative by converting methane into protein,potentially addressing both the need for alternative protein sources and reducing industrial greenhouse gas emissions.This study aimed to evaluate the effects of different levels of SCP inclusion(0%,25%,50%,and 75%fish meal replacement)on the health,gene expression,and gut microbiome of yellowtail kingfish(YTK,Seriola lalandi)following a 35-day growth trial.Results The study found that SCP inclusion at the highest level of fishmeal replacement(75%)induced a mild inflammatory response in the hindgut of the fish.However,micromorphological assessments of the hindgut,serum biochemistry,and gene expression analyses revealed no significant detrimental effects from SCP replacement.Notably,there were indications of improved lipid digestibility with SCP.Furthermore,SCP inclusion significantly enhanced microbial richness and altered the composition of the gut microbiome,introducing beneficial bacterial taxa that may contribute to improved gut health and resilience.Conclusions This study highlights SCP as a viable and sustainable alternative to fish meal in YTK diets.The findings suggest that SCP can be included in YTK diets without adverse health effects at moderate levels and may even offer benefits in terms of lipid digestibility and gut microbiome diversity.These results contribute to the advancement of more sustainable aquaculture practices.
文摘The dietary selenium (Se) requirement of yellowtail kingfish (Seriola lalandi) in normal and infected conditions was investigated. The fish were fed one of five experimental diets;a control un-supplemented diet (3.35 mg/kg Se) or diets supplemented with Se to provide 4.86, 5.38, 5.85 or 6.38 mg/kg Se. After feeding for 6 weeks, the fish were challenged by Vibrio anguillarum immersion and then observed for 4 weeks. Supplementation of Se had no effect on feed intake, feed conversion ratio and survival over 6 weeks of feeding;however, it significantly increased growth and Se content in muscle tissues. The optimal Se level for maximal growth of yellowtail kingfish estimated by second order regression was 5.56 mg/kg. Following the bacterial challenge, the immune-stimulating effects of Se were demonstrated in lysozyme and bactericidal activities, and there was a corresponding increase in survival and antibody response by supplementation of Se at ≥2 mg/kg (measured Se of ≥5.38 mg/kg). Under normal and infectious conditions, antioxidant capacity of fish measured as glutathione peroxidase activity increased by supplementation of Se. During post-challenge period, haematocrits were higher in the fish fed Se supplemented diets than the fish fed the control diet, while more macrophage aggregates were seen in the control group than in the others. Furthermore, there was evidence of myopathy in fish fed the diet without Se supplementation. Therefore, the results indicated that the optimal dietary Se requirement of yellowtail kingfish is 5.56 mg/kg.
文摘This paper exemplifies a primary step towards eliciting primary and secondary stakeholders’ views on management issues pertaining to kingfish fishery in Oman, and potential options for effective management of the fishery using questionnaire surveys and focus group interviews. There was consensus from stakeholder groups which included fishers, fishery managers, and fishery scientists that the current stock condition is not biologically sustainable. It is found that fishing effort control and technical measures are preferred to catch control by both groups. The role of mass media and the traditional institution in communicating fisheries issues are found to be relatively minor. Although the overall rating on the comprehensiveness of the proposed plan is promising, there are significant differences between the two groups with regard to legislative arrangements (χ<sup>2</sup> = 24.793, p-value = 0.000), management goals (χ<sup>2</sup> = 16.206, p-value = 0.001), operational objectives (χ<sup>2</sup> = 19.884, p-value = 0.000), performance indicators (χ<sup>2</sup> = 15.524, p-value = 0.001), and measures (χ<sup>2</sup> = 13.483, p-value = 0.004). Policy implications of the key findings are discussed in both national and regional contexts. Management authorities can use these findings to design an appropriate plan of actions for achieving sustainability in this fishery.
文摘Background: Water clarity may negatively influence rate of plunge diving and prey capture success of piscivorous plunge-diving birds, and therefore has implications for their conservation in polluted urban wetlands. We studied the relationship between water clarity and the abundance and prey capture success of Pied Kingfishers(Ceryle rudis) and Common Terns(Sterna hirundo) in two polluted coastal waters of south-east Ghana—the Weija Lake and Densu Delta Ramsar Site.Methods: On each wetland, data on abundance and prey capture success of plunge-divers were collected in four spatio-temporal quadrats of 100 m × 100 m and analysed with concurrent measurements of water quality parameters using GLM regression with Pearson's correlation coefficients.Results: Mean prey capture success of Pied Kingfishers(34.7 e two species responded differently to water clarity. The± 13.1%) and Common Terns(35.3 abundance of Common Terns was± 11.0%) were similar but th significantly higher in less transparent/more turbid water while that of Pied Kingfishers showed no significant relationship with turbidity and transparency. In contrast, the prey capture success of Common Terns was neither related to transparency nor turbidity, as opposed to that of Pied Kingfishers which was significantly higher in more turbid/less transparent waters. Correlations between capture success and bird abundance, as well as capture attempts were insignificant, suggesting that increased fish abundance associated with cloudy water may not necessarily promote higher abundance and capture success of foraging birds. Thus, when foraging in less transparent water, capture success may depend more on predator avoidance by fish prey than lower prey detectability of foraging birds.Conclusion: Within a gradient of 15–51 cm transparency studied, lower water clarity did not constrain prey capture success of Common Terns and Pied Kingfishers. Further studies on the foraging ecology of plunge-divers in coastal Ghana are however required to make firm conclusions on the relationship between water clarity and foraging birds and fish prey abundances, as well as capture success.
文摘为提升chirplet变换(chirplet transform,CT)估算瞬时频率的精度,在CT基础上结合花斑翠鸟优化(pied kingfisher optimizer,PKO)和径向基移动最小二乘(radial basis function moving least squares,RBFMLS)算法提出了一种识别结构瞬时频率的新方法。该方法采用正定紧支径向基函数作为移动最小二乘近似的权函数,对CT的能量脊线进行估算,同时应用PKO对RBFMLS节点支撑半径和CT窗函数宽度进行优化。通过一组解析信号数值算例和一个时变拉索试验验证了所提方法的有效性。研究结果表明,该方法能有效改善信号分析的能量聚集性,提高瞬时频率的识别精度。
