复合动植物蛋白部分替代鱼粉对大菱鲆幼鱼生长、体成分及生理生化指标的影响

本研究设计5组等氮等能(粗蛋白为53%,能量为25KJ/g)的实验饲料,以60%的鱼粉饲料组作为对照(D1),豆粕∶花生粕∶鱼溶浆粉∶鸡肉粉(2∶1∶3∶2)的复合蛋白替代40%(D2)、50%(D3)、60%(D4)和70%(D5)的鱼粉,养殖大菱鲆幼鱼(Scophthalmus maximus L.)初始体重(53.0±0.2) g,养殖周期84 d,每天定时(08:00,16:30)投喂2次,投喂量为体重的1.5%～2%。实验结果显示,各处理组之间幼鱼存活率、饲料系数和摄食率均无显著性差异(P0.05);与对照组相比,D4和D5组增重率显著降低(P0.05);肥满度在D2组达到最高值,显著高于D3、D4和D5组(P0.05);脏体比(VSI)、肝体比(HSI)和肠体比(ISI)均在D2组达到最低值,均显著低于D5组(P0.05);复合动植物蛋白替代鱼粉对大菱鲆幼鱼全鱼水分和粗蛋白含量均无显著影响(P0.05);各替代组全鱼粗脂肪含量显著高于对照组(P0.05);全鱼灰分含量在D5组显著低于对照组(P0.05);各组间背肌水分、粗蛋白、粗脂肪和灰分含量均无显著性差异(P0.05);复合动植物蛋白替代鱼粉对鱼体肌肉非必需氨基酸和必需氨基酸总量无显著影响(P0.05);各替代组均显著提高了血清谷草转氨酶和谷丙转氨酶活性(P0.05);总蛋白浓度在D2组显著高于D4和D5组(P0.05);血糖浓度在D2和D3组显著低于其他3组(P0.05);D3、D4和D5组甘油三酯浓度和高密度脂蛋白浓度均显著低于对照组和D2组(P0.05);各替代组胆固醇和低密度脂蛋白浓度均显著低于对照组(P0.05);各组之间碱性磷酸酶浓度无显著差异(P0.05)。研究结果表明,复合动植物蛋白可有效替代50%鱼粉而不影响大菱鲆幼鱼生长性能和部分生理生化指标。

Effects of Replacement of Fish Meal With an Animal and Plant Protein Mixture on Growth, Body Composition, and Physiological and Biological Indices of Juvenile Turbot (Scophthalmus maximus L.)

A 12-week feeding trial was conducted to evaluate the effects of replacement of fish meal with alternative proteins on growth performance, body composition, and physiological and biological indices of juvenile turbot (Scophthalmus maximus L.). Five isonitrogenous and isolipidic practical diets were formulated to contain graded levels (100%, 60%, 50%, 40%, and 30%) of fish meal (D1~D5); the D1 group was used as the control. A protein blend of four ingredients (soybean meal, peanut meal, stickwater meal, poultry by-product meal = 2:1:3:2) were used to replace the fish meal; subsequently, amino acids were supplemented in the low fish meal diet to obtain similar amino acid profiles to the high fish meal diet. Each diet was randomly assigned to triplicate groups of 30 fish (initial weight, (53.0±0.2) g)] per aquarium. The results of the survival rate, feed conversion ratio, feed intake, whole body moisture and crude protein, dorsal muscle moisture, crude protein, crude lipid, and ash content did not show any significant differences between any of the groups (P>0.05), whereas the diets with low fish meal content (D4/D5) significantly reduced the weight gain rate of fish compared with the control diet (P<0.05). The condition factor was significantly enhanced in the D2 treatment compared with the D3, D4, and D5 groups (P<0.05). However, the viscerosomatic and hepatosomatic indices were significantly reduced in the D2 treatment compared with the D5 (P<0.05). The dietary inclusion of the animal and plant protein mixture significantly elevated the whole-body crude lipid content (P<0.05). The whole-body ash content in the D5 treatment was significantly lower than the control diet (P<0.05). The essential amino acid compositions of the muscle were not significantly affected by the replacement of dietary fish meal with animal and plant protein mixtures (P>0.05). The dietary inclusion of animal and plant protein mixture significantly elevated serum aspartate aminotransferase and alanine transaminase activities (P<0.05). All the substituted protein diets caused significantly reduced serum cholesterol and low-density lipoprotein cholesterol (P<0.05), but only D3~D5 diets caused a significantly decreased serum high-density lipoprotein cholesterol (P<0.05). The dietary inclusion of animal and plant protein mixture had no strong effects on the total protein content and the alkaline phosphatase content (P>0.05). The replacement of up to 50% of dietary fish meal with an animal and plant protein mixture did not impair growth or reduce the feed efficiency of juvenile turbot.