饲料蛋白水平对大规格草鱼生长性能、消化酶活性和抗氧化能力的影响OA

The experiment aimed to investigate the effects of feed with different protein levels on the growth performance,digestive enzyme activity,and antioxidant capacity of large-sized grass carp.A total of 360 healthy grass carps with an initial weight of(1 902.32±7.61)g were randomly divided into six groups,with four replicates per group and 15 fish per replicate,groups CP1,CP2,CP3,CP4,CP5 and CP6 were fed with diets containing 26.52%,28.05%,30.97%,31.85%,34.67%and 35.79%protein,respectively.The pre-test period was two weeks,and the formal test period was eight weeks.The results showed that as the protein level in the feed increased,the weight gain rate of the grass carp first increased and then decreased,and the weight gain rate in groups CP4 and CP5 was significantly higher than group CP1(P<0.05).The midgut trypsin activity in groups CP4,CP5,and CP6 was significantly higher than that in group CP1(P<0.05),while the midgut amylase activity in groups CP3 and CP5 was significantly lower than that in group CP1(P<0.05).The liver trypsin activity in group CP5 was significantly higher than that in group CP1(P<0.05),and the lipase activity in group CP1 was significantly higher than that in groups CP4 and CP6(P<0.05).The liver superoxide dismutase(SOD)activity in groups CP3 and CP4 was significantly higher than that in group CP1(P<0.05).The glutathione peroxidase(GSH-Px)activity in group CP3 was significantly higher than that in group CP1(P<0.05),and the malondialdehyde(MDA)content was significantly lower than that in group CP1(P<0.05).The study shows that an appropriate protein level in feed can improve the growth performance,digestive enzyme activity,and anti-stress capacity of grass carp.When using weight gain rate as the evaluation index,the effect is better when the dietary protein level is 29.09%.