This study addressed the escalating demand for aquatic feed by exploring the potential of alfalfa nutrient concentrate(ANC) as feed ingredient for rainbow trout. Test diets contained varying ANC levels(0%, 5%,10%, 15%...This study addressed the escalating demand for aquatic feed by exploring the potential of alfalfa nutrient concentrate(ANC) as feed ingredient for rainbow trout. Test diets contained varying ANC levels(0%, 5%,10%, 15%, and 20%) to replace fishmeal(32% in the 0% ANC diet) to achieve equal digestible protein and were processed using a cooking extrusion method. Analysis of feed pellets showed that pellet density increased with ANC levels(P < 0.001), resulting in sinking pellets at 20% ANC. Water stability and durability were improved while oil leakage decreased with increasing ANC levels(P < 0.05). Two feeding trials were conducted to test the diets in flow-through water systems with three replicates per diet. The first 10-week trial evaluated their impact on feeding, fecal physical quality, and the apparent digestibility coefficient(ADC) of dietary nutrients in rainbow trout(initial body weight 18.0 ± 0.2 g). ANC inclusion did not impact the palatability and satiety feed intake of the fish(P > 0.05). However, the ADC of dry matter and phosphorus significantly decreased in fish fed the 20% ANC diet(P < 0.05). The second 9-week trial investigated the growth performance, nutrition quality, and metabolism of rainbow trout(initial body weight 19.0 ± 0.2 g). While all fish exhibited substantial growth, fish fed diets with 10% to20% ANC displayed lower specific growth rate and higher feed conversion ratio compared to those fed with 0% or 5% ANC(P < 0.05). The whole body protein content was higher in fish fed 5% ANC compared to all other treatments(P = 0.030). The biochemical parameters of plasma were similar across treatments,except for a decrease in plasma phosphorus levels in fish fed a 10% ANC diet compared to those fed a 0%ANC diet(P = 0.033). Significant changes were observed in liver metabolism including tricarboxylic acid cycle, amino acid and energy metabolism pathways in fish fed the 20% ANC diet versus the 0% ANC diet(P < 0.05). These results demonstrate that ANC inclusion improved pellet physical quality without impairing feeding behavior and nutritional quality of the fish but inclusion ≥10% in the diet reduced fish growth. This study offers the first comprehensive assessment of the potential of ANC used in fish feed involving feed management, feeding evaluation, and the biological response.展开更多
Microplastics are emergent contaminants threatening aquatic organisms including aquacultured fish.This study investigated the effects of high-density polyethylene(HDPE,100 to 125 mm)on yellow perch(Perca flavescens)ba...Microplastics are emergent contaminants threatening aquatic organisms including aquacultured fish.This study investigated the effects of high-density polyethylene(HDPE,100 to 125 mm)on yellow perch(Perca flavescens)based on integrative evaluation including growth performance,nutritional status,nutrient metabolism,fish health,and gut microbial community.Five test diets(0,1,2,4,or 8 g HDPE/100 g diet)containing 41%protein and 10.5%lipid were fed to juvenile perch(average body weight,25.9±0.2 g;n=15)at a feeding rate of 1.5%to 2.0%body weight daily.The feeding trial was conducted in a flow-through water system for 9 wk with 3 tanks per treatment and 15 yellow perch per tank.No mortality or HDPE accumulation in the fish was found in any treatments.Weight gain and condition factor of fish were not significantly impacted by HDPE(P>0.05).Compared to the control group,fish fed the 8%HDPE diet had significantly decreased levels of protein and ash(P<0.05).In response to the increasing levels of HDPE exposure,the hepatosomatic index value,hepatocyte size,and liver glycogen level were increased,but lipid content was reduced in the liver tissues.Compared to the control treatment,fish fed the 8%HDPE diet had significant accumulations of total bile acids and different metabolism pathways such as bile acid biosynthesis,pyruvate metabolism,and carnitine synthesis.Significant enterocyte necrosis was documented in the foregut of fish fed the 2%or 8%HDPE diet;and significant cell sloughing was observed in the midgut and hindgut of fish fed the 8%HDPE diet.Fish fed the 2%HDPE diet harbored different microbiota communities compared to the control fish.This study demonstrates that HDPE ranging from 100 to 125 mm in feed can be evacuated by yellow perch with no impact on growth.However,dietary exposure to HDPE decreased whole fish nutrition quality,altered nutrient metabolism and the intestinal histopathology as well as microbiota community of yellow perch.The results indicate that extended exposure may pose a risk to fish health and jeopardize the nutrition quality of aquacultured end product.This hypothesis remains to be investigated further.展开更多
基金funding from USDA-NIFA-ASAFS (2019-70005-30283)support from the China Scholarship Council (201906910073l)
文摘This study addressed the escalating demand for aquatic feed by exploring the potential of alfalfa nutrient concentrate(ANC) as feed ingredient for rainbow trout. Test diets contained varying ANC levels(0%, 5%,10%, 15%, and 20%) to replace fishmeal(32% in the 0% ANC diet) to achieve equal digestible protein and were processed using a cooking extrusion method. Analysis of feed pellets showed that pellet density increased with ANC levels(P < 0.001), resulting in sinking pellets at 20% ANC. Water stability and durability were improved while oil leakage decreased with increasing ANC levels(P < 0.05). Two feeding trials were conducted to test the diets in flow-through water systems with three replicates per diet. The first 10-week trial evaluated their impact on feeding, fecal physical quality, and the apparent digestibility coefficient(ADC) of dietary nutrients in rainbow trout(initial body weight 18.0 ± 0.2 g). ANC inclusion did not impact the palatability and satiety feed intake of the fish(P > 0.05). However, the ADC of dry matter and phosphorus significantly decreased in fish fed the 20% ANC diet(P < 0.05). The second 9-week trial investigated the growth performance, nutrition quality, and metabolism of rainbow trout(initial body weight 19.0 ± 0.2 g). While all fish exhibited substantial growth, fish fed diets with 10% to20% ANC displayed lower specific growth rate and higher feed conversion ratio compared to those fed with 0% or 5% ANC(P < 0.05). The whole body protein content was higher in fish fed 5% ANC compared to all other treatments(P = 0.030). The biochemical parameters of plasma were similar across treatments,except for a decrease in plasma phosphorus levels in fish fed a 10% ANC diet compared to those fed a 0%ANC diet(P = 0.033). Significant changes were observed in liver metabolism including tricarboxylic acid cycle, amino acid and energy metabolism pathways in fish fed the 20% ANC diet versus the 0% ANC diet(P < 0.05). These results demonstrate that ANC inclusion improved pellet physical quality without impairing feeding behavior and nutritional quality of the fish but inclusion ≥10% in the diet reduced fish growth. This study offers the first comprehensive assessment of the potential of ANC used in fish feed involving feed management, feeding evaluation, and the biological response.
基金The current study was partially funded by the University of Wisconsin-Milwaukee(UWM,Project 150-25-3150-343 PRJ93WQ)USDA-ARS in-house project#s 5090-31320-004-00D and 5090-31320-005-00D+4 种基金UW-system water research fellowship and UWM SURF were supported to Emma K.KracoNaulin Foundation was awarded to Deng's lab to support part of the studyMerry Zohn was supported by fellowship with the Oak Ridge Institute for Science EducationXing Lu(201803260002)and Fei Huang(201806330033)were supported by the China Scholarship CouncilYing Ma was supported by the Education Department of Fujian Province,China.
文摘Microplastics are emergent contaminants threatening aquatic organisms including aquacultured fish.This study investigated the effects of high-density polyethylene(HDPE,100 to 125 mm)on yellow perch(Perca flavescens)based on integrative evaluation including growth performance,nutritional status,nutrient metabolism,fish health,and gut microbial community.Five test diets(0,1,2,4,or 8 g HDPE/100 g diet)containing 41%protein and 10.5%lipid were fed to juvenile perch(average body weight,25.9±0.2 g;n=15)at a feeding rate of 1.5%to 2.0%body weight daily.The feeding trial was conducted in a flow-through water system for 9 wk with 3 tanks per treatment and 15 yellow perch per tank.No mortality or HDPE accumulation in the fish was found in any treatments.Weight gain and condition factor of fish were not significantly impacted by HDPE(P>0.05).Compared to the control group,fish fed the 8%HDPE diet had significantly decreased levels of protein and ash(P<0.05).In response to the increasing levels of HDPE exposure,the hepatosomatic index value,hepatocyte size,and liver glycogen level were increased,but lipid content was reduced in the liver tissues.Compared to the control treatment,fish fed the 8%HDPE diet had significant accumulations of total bile acids and different metabolism pathways such as bile acid biosynthesis,pyruvate metabolism,and carnitine synthesis.Significant enterocyte necrosis was documented in the foregut of fish fed the 2%or 8%HDPE diet;and significant cell sloughing was observed in the midgut and hindgut of fish fed the 8%HDPE diet.Fish fed the 2%HDPE diet harbored different microbiota communities compared to the control fish.This study demonstrates that HDPE ranging from 100 to 125 mm in feed can be evacuated by yellow perch with no impact on growth.However,dietary exposure to HDPE decreased whole fish nutrition quality,altered nutrient metabolism and the intestinal histopathology as well as microbiota community of yellow perch.The results indicate that extended exposure may pose a risk to fish health and jeopardize the nutrition quality of aquacultured end product.This hypothesis remains to be investigated further.
