罗非鱼低鱼粉饲料中桑叶发酵蛋白替代鱼粉的研究

摘要

In order to study the feasibility of replacement of fish meal with fermented mulberry leaves protein in low fish meal diets for tilapia ( Oreochromis niloticus) , three isonitrogenous ( crude protein content was 32%) and isoenergetic ( gross energy was 15 MJ/kg) experimental diets were formulated by replacing 0 ( control) , 40% and 80% fish meal with fermented mulberry leaves protein on basis of a practical diet ( fish meal content was 5%) , and the corresponding supplemental levels of fermented mulberry leaves protein were 0, 4% and 8%, respectively. Each diet was randomly assigned to 3 replicates of 30 genetically improved farmed tilapia ( average body weight about 40 g) . The experiment lasted for 8 weeks. The results showed as follows: the fi-nal body weight, specific growth rate ( SGR) and protein efficiency ratio ( PER) in the 80% replacement level group were significantly lower than those in the control group ( P<0.05) , but there were no significant differ-ences between the 40% replacement level group and the control group (P>0.05). No significant differences were found in feed conversion ratio ( FCR ) and feeding rate ( FR ) . The fish in the 80% replacement level group had the lowest values of viscera somatic index ( VSI) , hepatopancreas somatic index ( HSI) and serum total cholesterol ( TC) , triglyceride ( TG) , low density lipoprotein cholesterol ( LDL-C) and blood glucose contents and the highest values of high density lipoprotein cholesterol ( HDL-C ) content, HDL-C/CHO and HDL-C/LDL-C, and the differences in those indices reached significance level between 80% replacement level group and 40% replacement level group or control group (P<0.05). There were no significant differences in condition factor ( CF) , and the contents of moisture, crude protein, ether extract and ash in whole body a-mong all groups ( P>0.05) . In conclusion, the growth is not affected when 40% fish meal replacement with fermented mulberry leaves protein in the low fish meal diet ( fish meal content is 5%) , and 80% replacement level can inhibit growth, but effectively reduce blood glucose and lipid contents.%在实用饲料(含5%鱼粉)的基础上,用桑叶发酵蛋白分别替代0(对照)、40%和80%的鱼粉,相应的桑叶发酵蛋白添加水平为0、4%和8%,配制成3种等氮(粗蛋白质含量32%)等能(总能15 MJ/kg)的试验饲料,饲喂初重约为40 g的吉富罗非鱼8周,以研究罗非鱼低鱼粉饲料中桑叶发酵蛋白替代鱼粉的可行性. 每种饲料设3个重复,每个重复饲喂30尾鱼. 结果显示:与对照组相比,40%替代水平不影响罗非鱼的生长(P>0.05),而80%替代水平显著降低罗非鱼的末重、特定生长率和蛋白质效率( P<0.05). 各组饲料系数和摄食率均无显著差异( P>0.05).80%替代水平组罗非鱼的脏体比、肝体比以及血清中总胆固醇、甘油三酯、低密度脂蛋白胆固醇和全血中葡萄糖(血糖)含量最低,血清高密度脂蛋白胆固醇含量及高密度脂蛋白胆固醇/总胆固醇、高密度脂蛋白胆固醇/低密度脂蛋白胆固醇最高,且与40%替代水平组和对照组均有显著差异( P<0.05). 各组罗非鱼肥满度以及全鱼水分、粗蛋白质、粗脂肪和粗灰分含量均无显著差异( P>0.05). 由此可见,在低鱼粉饲料(含5%鱼粉)中,桑叶发酵蛋白替代40%的鱼粉不会影响罗非鱼的生长,替代80%鱼粉会抑制罗非鱼的生长,但可以降低罗非鱼的血脂和血糖含量.