A 105-day feeding study was conducted to evaluate the effect of partial （0%, 20%, 40%, 60% and 80%） and complete （100%） substitution of dietary fish meal （FM） with frozen Artemia on growth performance and feed u...A 105-day feeding study was conducted to evaluate the effect of partial （0%, 20%, 40%, 60% and 80%） and complete （100%） substitution of dietary fish meal （FM） with frozen Artemia on growth performance and feed utilization of Giant freshwater prawn （Macrobrachium rosenbergii） post larvae （PL） reared in fiberglass tanks under controlled conditions. A total of 1080 M. rosenbergii PL, average weight of 6.10 ± 0.4 mg, were equally distributed over 18 fiberglass tanks, （1 m^3 each, and triplicate per treatment）. Six experimental isocaloric （14 MJ/kg/digestible energy） and isonitrogenous （35% crude protein） diets were lbrmulated. Control diet （D1, 100% FM） was formulated with FM as the main protein source （0% Artemia）. Diets D2-D6 were substituted with five dietary protein levels of frozen Artemia （20%, 40%, 60%, 80% and 100%）, respectively. Results showed that growth performance of M. rosenbergii PL fed different Artemia based diets was either equal or superior to prawn fed control FM diet. In addition, increasing dietary frozen Artemia replacement level from 20% up to 100% led to a significant （P 〈 0.05） increase in survival, growth and feed utilization, which indicate that the essential nutrient requirements needed for M. rosenbergii PL was covering with improving feed satiation of PLs. It could be concluded that frozen Artemia biomass instead of fishmeal in M. rosenbergii PL diets can improve survival rate, growth performance, feed utilization, contributing to reducing the use of FM in practical diets and the nursery phase could be shorter and more profitable.展开更多
We evaluated the effect of pH on larval development in larval Pacific oyster(Crassostrea gigas) and blood cockle(Arca inflata Reeve).The larvae were reared at pH 8.2(control),7.9,7.6,or 7.3beginning 30 min or 24 h pos...We evaluated the effect of pH on larval development in larval Pacific oyster(Crassostrea gigas) and blood cockle(Arca inflata Reeve).The larvae were reared at pH 8.2(control),7.9,7.6,or 7.3beginning 30 min or 24 h post fertilization.Exposure to lower pH during early embryonic development inhibited larval shell formation in both species.Compared with the control,larvae took longer to reach the D-veliger stage when reared under pH 7.6 and 7.3.Exposure to lower pH immediately after fertilization resulted in significantly delayed shell formation in the Pacific oyster larvae at pH 7.3 and blood cockle larvae at pH 7.6 and 7.3.However,when exposure was delayed until 24 h post fertilization,shell formation was only inhibited in blood cockle larvae reared at pH 7.3.Thus,the early embryonic stages were more sensitive to acidified conditions.Our results suggest that ocean acidification will have an adverse effect on embryonic development in bivalves.Although the effects appear subtle,they may accumulate and lead to subsequent issues during later larval development.展开更多
Sumithion is widely used to control brittle in paddy fields and tiger bug in fish larval rearing ponds. The objective of this study was to elucidate the toxic effects of sumithion on larval stages of stinging catfish ...Sumithion is widely used to control brittle in paddy fields and tiger bug in fish larval rearing ponds. The objective of this study was to elucidate the toxic effects of sumithion on larval stages of stinging catfish Heteropneustes fossilis. Larvae were exposed to two concentrations(150 and 250 μg/L) of sumithion with one control in three replicates of each. Larvae samples were collected at 20- and 24-h intervals followed by observation under a digital microscope. Exposures of stinging catfish larvae to sumithion produced deformities including irregular head shape, lordosis, yolk sac edema, body arcuation, tissue ulceration, etc. The mortality rates of larvae were significantly increased in response to increase in sumithion concentrations. Furthermore, around 30% of the total adult stinging catfish reared in sumithiontreated aquaculture ponds were found to be deformed permanently. These findings highlight that exposure of stinging catfish to sumithion at the critical and sensitive stages in their life cycle may significantly reduce the number of returning adults. Therefore, the use of sumithion for crop protection needs to be considered carefully and alternatives to sumithion should to be developed for controlling aquatic insects in aqua-ponds during larval rearing.展开更多
文摘A 105-day feeding study was conducted to evaluate the effect of partial （0%, 20%, 40%, 60% and 80%） and complete （100%） substitution of dietary fish meal （FM） with frozen Artemia on growth performance and feed utilization of Giant freshwater prawn （Macrobrachium rosenbergii） post larvae （PL） reared in fiberglass tanks under controlled conditions. A total of 1080 M. rosenbergii PL, average weight of 6.10 ± 0.4 mg, were equally distributed over 18 fiberglass tanks, （1 m^3 each, and triplicate per treatment）. Six experimental isocaloric （14 MJ/kg/digestible energy） and isonitrogenous （35% crude protein） diets were lbrmulated. Control diet （D1, 100% FM） was formulated with FM as the main protein source （0% Artemia）. Diets D2-D6 were substituted with five dietary protein levels of frozen Artemia （20%, 40%, 60%, 80% and 100%）, respectively. Results showed that growth performance of M. rosenbergii PL fed different Artemia based diets was either equal or superior to prawn fed control FM diet. In addition, increasing dietary frozen Artemia replacement level from 20% up to 100% led to a significant （P 〈 0.05） increase in survival, growth and feed utilization, which indicate that the essential nutrient requirements needed for M. rosenbergii PL was covering with improving feed satiation of PLs. It could be concluded that frozen Artemia biomass instead of fishmeal in M. rosenbergii PL diets can improve survival rate, growth performance, feed utilization, contributing to reducing the use of FM in practical diets and the nursery phase could be shorter and more profitable.
基金Supported by the Special Scientific Research Funds for Central Non-Profit Institutes,CAFS(No.2014A01 YYOl)the National Basic Research Program of China(973 Program)(No.2011CB409805)+1 种基金the Earmarked Fund for Modern Agro-Industry Technology Research System(No.CARS-48)the National Key Technology R&D Program of China(No.2011BAD45B01)
文摘We evaluated the effect of pH on larval development in larval Pacific oyster(Crassostrea gigas) and blood cockle(Arca inflata Reeve).The larvae were reared at pH 8.2(control),7.9,7.6,or 7.3beginning 30 min or 24 h post fertilization.Exposure to lower pH during early embryonic development inhibited larval shell formation in both species.Compared with the control,larvae took longer to reach the D-veliger stage when reared under pH 7.6 and 7.3.Exposure to lower pH immediately after fertilization resulted in significantly delayed shell formation in the Pacific oyster larvae at pH 7.3 and blood cockle larvae at pH 7.6 and 7.3.However,when exposure was delayed until 24 h post fertilization,shell formation was only inhibited in blood cockle larvae reared at pH 7.3.Thus,the early embryonic stages were more sensitive to acidified conditions.Our results suggest that ocean acidification will have an adverse effect on embryonic development in bivalves.Although the effects appear subtle,they may accumulate and lead to subsequent issues during later larval development.
文摘Sumithion is widely used to control brittle in paddy fields and tiger bug in fish larval rearing ponds. The objective of this study was to elucidate the toxic effects of sumithion on larval stages of stinging catfish Heteropneustes fossilis. Larvae were exposed to two concentrations(150 and 250 μg/L) of sumithion with one control in three replicates of each. Larvae samples were collected at 20- and 24-h intervals followed by observation under a digital microscope. Exposures of stinging catfish larvae to sumithion produced deformities including irregular head shape, lordosis, yolk sac edema, body arcuation, tissue ulceration, etc. The mortality rates of larvae were significantly increased in response to increase in sumithion concentrations. Furthermore, around 30% of the total adult stinging catfish reared in sumithiontreated aquaculture ponds were found to be deformed permanently. These findings highlight that exposure of stinging catfish to sumithion at the critical and sensitive stages in their life cycle may significantly reduce the number of returning adults. Therefore, the use of sumithion for crop protection needs to be considered carefully and alternatives to sumithion should to be developed for controlling aquatic insects in aqua-ponds during larval rearing.
