低鱼粉饲料中添加酶解豆粕对凡纳滨对虾生长性能和抗胁迫机能的影响

为研究在养殖过程中降低鱼粉用量的同时保持凡纳滨对虾良好的生长性能和抗逆能力,实验在含10%鱼粉的基础饲料中,分别添加酶解豆粕(PSM) 0%(A)、2.5%(B)、3.5%(C)、4.5%(D)、5.5%(E)制成5组等氮等能饲料,分别投喂初始体质量为(0.45±0.02) g的凡纳滨对虾幼虾8周,检测对虾生长性能及抗胁迫机能。结果显示,8周养殖实验结束后,各实验组对虾的终末体质量为14.65～15.38 g/尾,各组间对虾终末均重、成活率和饲料系数指标均无显著性差异;A组对虾肌肉粗蛋白质含量显著低于其他各实验组;C组、D组和E组对虾肌肉粗脂肪含量显著高于A组;各组间灰分和水分均无显著性差异;D组和E组对虾肝胰腺蛋白酶、淀粉酶、脂肪酶、血清溶菌酶和血清总超氧化物歧化酶活性(T-SOD)均显著高于A组;A组对虾血清丙二醛(MDA)含量显著高于D组和E组。人工急性感染高剂量副溶血性弧菌的胁迫实验中,A组对虾在弧菌感染48和60 h时的累积死亡率均显著高于D组对虾同期的累积死亡率;低剂量副溶血性弧菌人工急性感染后,在凡纳滨对虾鳃组织中检测Toll受体、免疫缺陷(IMD)和溶菌酶3种免疫相关基因的表达量,结果显示,对虾Toll受体、IMD和溶菌酶mRNA表达量最大峰值分别出现在添加酶解豆粕的C组、B组和D组,峰值出现时刻分别为感染后24、42和24 h。研究表明,含10%鱼粉的饲料中添加0%～5.5%酶解豆粕对凡纳滨对虾的生长性能改善效果不显著,酶解豆粕会显著提高凡纳滨对虾肌肉粗蛋白质含量和粗脂肪含量;显著降低对虾血清丙二醛含量;同时也会显著改变凡纳滨对虾对弧菌的抵抗力及其免疫相关基因的时空表达,酶解豆粕添加量达到4.5%时可使养殖的凡纳滨对虾获得最佳的抗弧菌能力。

Effect of proteolytic soybean meal in low-fish-meal-diet on growth performance and stress resistance of Litopenaeus vannamei

In order to explore how to reduce the amount of fish meal while maintaining the good growth performance and stress resistance of Litopenaeus vannamei, in this study, the basic diet containing 10% fish meal was added with 0% (A), 2.5% (B), 3.5% (C), 4.5% (D) and 5.5% (E) of proteolytic soybean meal (PSM) to produce five groups of isonitrogonous isoenergetic feed. L.vannamei juveniles with initial body weight of (0.45+0.02) g were fed for 8 weeks. Then the growth performance and stress resistance of L.vannamei were assessed. The results showed that the final body weight of shrimps in each experimental group ranged from 14.65 to 15.38 g/individual after 8-week culture experiment, and there were no significant differences in weight gain, survival rate and feed coefficient among the groups. The crude protein content of shrimp muscle in group A was significantly lower than those in other experimental groups. The crude fat contents of shrimp muscle in group C, D and E were significantly higher than that in group A. There was no significant differences in ash and moisture content among other groups. The activities of hepatopancreas protease, hepatopancreas amylase, hepatopancreas lipase, serum lysozyme and serum T-SOD in shrimp fed D and E diets were significantly higher than that in group A. The serum MDA content in group A was significantly higher thsan those in other groups. In the stress test of artificial acute infection with high dose Vibrio Parahaemolyticus, the cumulative mortality of shrimp in group A at 48 h and 60 h post Vibrio infection was significantly higher than that in group D. The expression levels of Toll receptor, immune deficiency (IMD) and Lysozyme were detected in shrimp gill tissues after artificial acute infection with low dose V.parahaemolyticus. The results showed that the peak values of Toll receptor, IMD and Lysozyme mRNA expression appeared in group C at 24 h post infection, group B at 42 h post infection and group D at 24 h post infection, respectively. To sum up: in the feed containing 10% fish meal, the effect of proteolytic soybean meal less than 5.5% on the growth performance of L.vannamei is not significant. The dietary proteolytic soybean meal could significantly increase the crude protein content and crude fat content in muscle and decrease the MDA content in shrimp serum. Under the experimental conditions, the dietary proteolytic soybean meal significantly changes the resistance of L.vannamei to Vibrio and the temporal and spatial expression of immune-related genes. Using 4.5% proteolytic soybean meal in feed containing 10% fish meal can obtain the best anti-Vibrio ability of cultured L.vannamei.