The diurnal variation in the sun's altitude alters the red-to-blue light spectrum ratio under identical water layers.This study explores how juvenile steelhead trout(Oncorhynchus mykiss)(initial weight:34.67 g...The diurnal variation in the sun's altitude alters the red-to-blue light spectrum ratio under identical water layers.This study explores how juvenile steelhead trout(Oncorhynchus mykiss)(initial weight:34.67 g±2.69 g)responds to these fluctuating light conditions,focusing on growth,daily activity levels,and energy budget.During 16 weeks,the experiment was conducted to examine six lighting scenarios:12 h white light followed by 12 h darkness(12W);12 h blue light followed by 12 h darkness(12B);12 h red light followed by 12 h darkness(12R);1.5 h blue light,9 h red light,and again 1.5 h blue light followed by 12 h darkness(3B9R);3 h blue light,6h red light,and again 3 h blue light followed by 12 h darkness(6B6R);and 12 h combined blue and red lights followed by 12 h darkness(T12BR).The findings reveal that the 3B9R lighting condition notably enhanced specific growth rate(SGR),feed conversion efficiency(FCE),and growth energy allocation,while diminishing daily activity levels in steelhead trout.Conversely,under the 6B6R condition,there was a significant reduction in SGR and FCE,indicating that growth was inhibited.Under the 12R condition,despite the high activity and respiratory energy loss,the trout exhibited improved SGR and FCE with reduced fecal energy loss.The study suggests that 3B9R and 12R lighting conditions might be beneficial in commercial steelhead trout farming,potentially lowering costs and boosting production.These results offer valuable insights for the application of supplementary lighting technology in salmon aquaculture.展开更多
In this study, the changes of the fatty acid composition of phospholipid in different tissues(muscle, heart, brain and spleen) of steelhead trout(Oncorhynchus mykiss) were analyzed when the water temperature decreased...In this study, the changes of the fatty acid composition of phospholipid in different tissues(muscle, heart, brain and spleen) of steelhead trout(Oncorhynchus mykiss) were analyzed when the water temperature decreased gradually from 16 to 12℃℃, 8℃, 6℃, 4℃, 2 and 1℃℃. Three fish individuals each tank(average weight 70.32 g ± 9.12 g) were collected and used to analysis at each designed temperatures. At normal temperature(16℃), the fatty acid composition of phospholipid of muscle and heart was similar each other. The highest concentration of saturate fatty acids(SFA) was found in the phospholipid of spleen. The brain phospholipid contained higher oleic acid(18:1 n9) than the phospholipid of other tissues at 16℃. When the environmental temperature decreased, the concentration of unsaturated fatty acids of phospholipids in all tissues increased, and accordingly the ratio pf the unsaturated to saturated fatty acids(U/S) and unsaturation index(UI) increased, indicating that steelhead trout can compensate temperature-dependent changes in membrane fluidity by remodeling the fatty acid composition of phospholipids. The changes in the fatty acid composition of phospholipid were tissue-specific. At the early stages of the experiment(16 to 8℃℃), the fatty acid composition of phospholipid changed remarkably in muscle, heart, and spleen. When temperature decreased to less than 8℃, an obvious response of phospholipid fatty acid was observed in all tissues. The change of phospholipid composition of steelhead trout tissues may be affected by both cold stress and starvation when the temperature decreased to 2℃, and the change of phospholipid composition of muscle was very obvious.展开更多
This study examined the effect of different salinities(0, 5, 10, 15, 20, 25 and 30) on the growth performance and energy budget of juveniles of two different ecotypes of Oncorhynchus mykiss, landlocked rainbow trout a...This study examined the effect of different salinities(0, 5, 10, 15, 20, 25 and 30) on the growth performance and energy budget of juveniles of two different ecotypes of Oncorhynchus mykiss, landlocked rainbow trout and anadromous steelhead trout. In the 42 d experiment, fish were cultured in three replicate tanks per salinity treatment(eight fish per tank). At the end of the experiment, the growth of rainbow and steelhead trouts was significantly higher at salinities of 5 and 10, respectively, than at all other salinities. The protein, lipid and energy content of both ecotypes declined with the increase of salinity. Based on their energy budgets, the percentage of energy consumed for growth by rainbow and steelhead trouts were significantly higher at salinities of 5(34.00% ±1.69%) and 10(43.76% ± 1.29%), respectively, than at all other salinities. The percentage of energy consumed for respiration by rainbow and steelhead trouts was lower at salinities of 5(54.90% ± 1.77%) and 10(46.73% ± 0.62%), respectively, than at all other salinities. Our results indicated that the salinity adaptation ability of juvenile steelhead trout was slightly better than that of juvenile rainbow trout, and salinities of 10 and 5, respectively, were most suitable for growth of these two fishes.展开更多
This study was performed to evaluate the effect of temperature on the carbon(C),nitrogen(N),and phosphorus(P)nu-trient budgets of adult steelhead trout(Oncorhynchus mykiss)with different body sizes.A complete two-fact...This study was performed to evaluate the effect of temperature on the carbon(C),nitrogen(N),and phosphorus(P)nu-trient budgets of adult steelhead trout(Oncorhynchus mykiss)with different body sizes.A complete two-factor experiment was con-ducted at four temperatures,i.e.,9(T9),13(T13),16(T1℃℃℃6),and 19(T19);and three body sizes,℃i.e.,0.65 kg±0.02 kg(S1),1.22 kg±0.06 kg(S2),and 2.05 kg±0.09 kg(S3).The following properties of steelhead trout were determined:C,N,and P nutrient budgets;feed intake rate;fecal production rate;oxygen consumption rate;ammonia excretion rate;phosphorus excretion rate;scope of the growth of C,N,and P;and absorption efficiency of C,N,and P.Results showed no significant interaction between temperature and body size in terms of the nutrient budgets of steelhead trout.However,temperature and body size played important separate roles in the nutrient budgets except for the absorption efficiency of nitrogen.The feed intake rate,fecal production rate,ammonia excretion rate,phosphorus excretion rate,and scope of the growth of C,N,and P were the highest in the T16 treatments.The absorption effi-ciency of C and P decreased as temperature increased.Nonlinear multiple regression results indicated that 15 was the approximate℃optimal temperature for the feeding and growth of steelhead trout.The feed intake rate,fecal production rate,oxygen consumption rate,ammonia excretion rate,phosphorus excretion rate,and scope of the growth of C,N,and P per unit of the body weight of fish decreased as body size increased.The absorption efficiency of C increased as body weight increased,and the absorption efficiencies of P in the S2 and S3 treatments were significantly higher than those in the S1 treatment.During the culture of steelhead trout,the daily ratio should be adjusted with changes in the temperature and body size of fish.Furthermore,managers should focus on the risk of hypoxia at high water temperatures.展开更多
基金supported by the Shandong Postdoctoral Science Foundation(No.SDCX-ZG-202302007)the National Key Research and Development Program of China(No.2019YFD0901000)+1 种基金the National Natural Science Foundation of China(Nos.U1906206 and 31872575)the Major Science and Technology Innovation Project of Shandong Province(No.SD2019YY006)。
文摘The diurnal variation in the sun's altitude alters the red-to-blue light spectrum ratio under identical water layers.This study explores how juvenile steelhead trout(Oncorhynchus mykiss)(initial weight:34.67 g±2.69 g)responds to these fluctuating light conditions,focusing on growth,daily activity levels,and energy budget.During 16 weeks,the experiment was conducted to examine six lighting scenarios:12 h white light followed by 12 h darkness(12W);12 h blue light followed by 12 h darkness(12B);12 h red light followed by 12 h darkness(12R);1.5 h blue light,9 h red light,and again 1.5 h blue light followed by 12 h darkness(3B9R);3 h blue light,6h red light,and again 3 h blue light followed by 12 h darkness(6B6R);and 12 h combined blue and red lights followed by 12 h darkness(T12BR).The findings reveal that the 3B9R lighting condition notably enhanced specific growth rate(SGR),feed conversion efficiency(FCE),and growth energy allocation,while diminishing daily activity levels in steelhead trout.Conversely,under the 6B6R condition,there was a significant reduction in SGR and FCE,indicating that growth was inhibited.Under the 12R condition,despite the high activity and respiratory energy loss,the trout exhibited improved SGR and FCE with reduced fecal energy loss.The study suggests that 3B9R and 12R lighting conditions might be beneficial in commercial steelhead trout farming,potentially lowering costs and boosting production.These results offer valuable insights for the application of supplementary lighting technology in salmon aquaculture.
基金jointly funded by the National Natural Science Foundation of China (Nos. 31572634 and 31702364)the Fundamental Research Funds for the Central Universities of China (No. 20161205)+1 种基金the Key Research and Development Program of Shandong Province (Nos. 2016CYJS04A01 and 2017CXGC0106)Science and Technology Planning Project of Guangdong Province, China (No. 2017B030314052)
文摘In this study, the changes of the fatty acid composition of phospholipid in different tissues(muscle, heart, brain and spleen) of steelhead trout(Oncorhynchus mykiss) were analyzed when the water temperature decreased gradually from 16 to 12℃℃, 8℃, 6℃, 4℃, 2 and 1℃℃. Three fish individuals each tank(average weight 70.32 g ± 9.12 g) were collected and used to analysis at each designed temperatures. At normal temperature(16℃), the fatty acid composition of phospholipid of muscle and heart was similar each other. The highest concentration of saturate fatty acids(SFA) was found in the phospholipid of spleen. The brain phospholipid contained higher oleic acid(18:1 n9) than the phospholipid of other tissues at 16℃. When the environmental temperature decreased, the concentration of unsaturated fatty acids of phospholipids in all tissues increased, and accordingly the ratio pf the unsaturated to saturated fatty acids(U/S) and unsaturation index(UI) increased, indicating that steelhead trout can compensate temperature-dependent changes in membrane fluidity by remodeling the fatty acid composition of phospholipids. The changes in the fatty acid composition of phospholipid were tissue-specific. At the early stages of the experiment(16 to 8℃℃), the fatty acid composition of phospholipid changed remarkably in muscle, heart, and spleen. When temperature decreased to less than 8℃, an obvious response of phospholipid fatty acid was observed in all tissues. The change of phospholipid composition of steelhead trout tissues may be affected by both cold stress and starvation when the temperature decreased to 2℃, and the change of phospholipid composition of muscle was very obvious.
基金jointly funded by the National Natural Science Foundation of China (Nos. 31702364 and 3157 2634)the Primary Research and Development Program of Shandong Province (Nos. 2016CYJS04A01 and 2017CXGC0106)
文摘This study examined the effect of different salinities(0, 5, 10, 15, 20, 25 and 30) on the growth performance and energy budget of juveniles of two different ecotypes of Oncorhynchus mykiss, landlocked rainbow trout and anadromous steelhead trout. In the 42 d experiment, fish were cultured in three replicate tanks per salinity treatment(eight fish per tank). At the end of the experiment, the growth of rainbow and steelhead trouts was significantly higher at salinities of 5 and 10, respectively, than at all other salinities. The protein, lipid and energy content of both ecotypes declined with the increase of salinity. Based on their energy budgets, the percentage of energy consumed for growth by rainbow and steelhead trouts were significantly higher at salinities of 5(34.00% ±1.69%) and 10(43.76% ± 1.29%), respectively, than at all other salinities. The percentage of energy consumed for respiration by rainbow and steelhead trouts was lower at salinities of 5(54.90% ± 1.77%) and 10(46.73% ± 0.62%), respectively, than at all other salinities. Our results indicated that the salinity adaptation ability of juvenile steelhead trout was slightly better than that of juvenile rainbow trout, and salinities of 10 and 5, respectively, were most suitable for growth of these two fishes.
基金funded by the National Key Research and Development Program of China(No.2019YFD0901000)the National Natural Science Foundation of China(No.31872575)the Key Research and Development Program of Shandong Province(No.2021SFGC0701).
文摘This study was performed to evaluate the effect of temperature on the carbon(C),nitrogen(N),and phosphorus(P)nu-trient budgets of adult steelhead trout(Oncorhynchus mykiss)with different body sizes.A complete two-factor experiment was con-ducted at four temperatures,i.e.,9(T9),13(T13),16(T1℃℃℃6),and 19(T19);and three body sizes,℃i.e.,0.65 kg±0.02 kg(S1),1.22 kg±0.06 kg(S2),and 2.05 kg±0.09 kg(S3).The following properties of steelhead trout were determined:C,N,and P nutrient budgets;feed intake rate;fecal production rate;oxygen consumption rate;ammonia excretion rate;phosphorus excretion rate;scope of the growth of C,N,and P;and absorption efficiency of C,N,and P.Results showed no significant interaction between temperature and body size in terms of the nutrient budgets of steelhead trout.However,temperature and body size played important separate roles in the nutrient budgets except for the absorption efficiency of nitrogen.The feed intake rate,fecal production rate,ammonia excretion rate,phosphorus excretion rate,and scope of the growth of C,N,and P were the highest in the T16 treatments.The absorption effi-ciency of C and P decreased as temperature increased.Nonlinear multiple regression results indicated that 15 was the approximate℃optimal temperature for the feeding and growth of steelhead trout.The feed intake rate,fecal production rate,oxygen consumption rate,ammonia excretion rate,phosphorus excretion rate,and scope of the growth of C,N,and P per unit of the body weight of fish decreased as body size increased.The absorption efficiency of C increased as body weight increased,and the absorption efficiencies of P in the S2 and S3 treatments were significantly higher than those in the S1 treatment.During the culture of steelhead trout,the daily ratio should be adjusted with changes in the temperature and body size of fish.Furthermore,managers should focus on the risk of hypoxia at high water temperatures.
