发酵豆粕替代鱼粉对凡纳滨对虾生长、免疫相关酶及免疫相关基因表达的影响

Effects of fermented soybean meal replacing fish meal on the growth performance, immune-related enzymes and gene expression of Litopenaeus vannamei

从免疫相关酶活及基因转录水平角度探讨发酵豆粕替代鱼粉对凡纳滨对虾健康生长及免疫机能机制的影响。实验设置5种实用饲料,以30%鱼粉组(FM)为对照组,分别用4%(FSM4)、8%(FSM8)、12%(FSM12)和16%(FSM16)的发酵豆粕,替代9.7%、19.4%、29.1%和38.8%鱼粉,分为4个处理组,饲养体质量为(7.62±0.23)g的凡纳滨对虾60 d后,统计生长性能,检测肌肉营养成分、血清及肝胰腺免疫相关酶活性,肝胰腺HSP70和鳃Toll受体、IMD、溶菌酶(LZM)免疫相关基因m RNA的表达水平。结果显示:(1)与对照组相比,发酵豆粕替代鱼粉对凡纳滨对虾成活率无显著影响;过低或过高水平的发酵豆粕替代鱼粉皆会影响凡纳滨对虾的特定生长率。(2)除FSM12组外,肌肉粗蛋白含量发酵豆粕替代组均低于对照组;粗脂肪含量随着发酵豆粕替代量的升高而降低,FSM16组最低。(3)血清谷丙转氨酶活FSM4和FSM16组显著高于对照组;谷草转氨酶活FSM4组最高,而FSM8组最低;除FSM12组外;碱性磷酸酶活性发酵豆粕替代组显著高于对照组;除FSM16组外,血清总蛋白与肝胰腺丙二醛含量发酵豆粕替代组与对照组无显著性差异。(4)随着发酵豆粕替代量增加,鳃Toll受体m RNA表达呈上升趋势,鳃IMD m RNA表达则呈先升后降趋势,发酵豆粕替代比例过高会降低鳃LZM m RNA表达水平,而肝胰腺HSP70 m RNA表达量则随着发酵豆粕替代比例增加呈上升趋势。综上所述,发酵豆粕适量替代鱼粉对凡纳滨对虾生长性能无显著影响,并可提高免疫相关酶活,改变免疫相关基因的表达。本实验条件下适宜发酵豆粕用量为8%~12%;替代量过高,会引起机体的过度应激。

This study intends to explore the health and immunologly mechanism of fermented soybean meal replacing fish meal affecting the growth of the Litopenaeus vannamei based on varying immune-related enzymes activity and genes transcription levels.Five experiment diets were designed,in which 30%of fish meal diet(FM)as the control group,and 4%(FSM4),8%(FSM8),12%(FSM12)and 16%(FSM16)of the fermented soybean meal were used to replace 9.7%,19.4%,29.1%and 38.8%of the fish meal respectively.After 60-day feeding test for L.vannamei[initial weight=(7.62±0.23)g],the growth performance,muscle nutrition composition,serum and hepatopancreas immune enzymes activity,the expression levels of HSP70 mRNA in hepatopancreas and Toll receptor mRNA,IMD mRNA and LZM mRNA in gill were determined.The results indicated that the substitution of fermented soybean meal for fish meal had no significant effect on the survival rate of the shrimp compared with the control group,both too low and too high levels of fermented soybean meal reduced the specific growth rate of shrimp.Muscle crude protein content was lower in the addition group of fermented soybean meal than the FM group with no significant difference except FSM12,crude fat has a tendency to decrease with the increase of fermented soybean meal,and the lowest value was found in the FSM16 group.The serum alanine aminotransferase(ALT)in FSM4 and FSM16 groups was significantly higher than that of control group,and the aspartate amino transferase(AST)was the highest and lowest in FSM4 group and FSM8 group respectively;except FSM12 group,serum ALP showed no marked difference between other FSM groups and the control group;as for TP in serum and MDA in hepatopancreas,there was no statistic difference either between FSM groups(except FSM16 group)and the control.With the increase of the amount of fermented soybean meal,the level of gill Toll receptor mRNA expression increased,and the level of IMD mRNA expression increased first and then decreased,and excessive or less of the added fermented soybean meal would decrease the expression of LZM mRNA in gill,while the expression of HSP70 mRNA in hepatopancreas increased with the increase of fermented soybean meal.To sum up,in the conditions of this experiment,optimum amount of the fermented soybean meal was 8%to 12%,i.e replacing 19.4%–29.1%of fish meal without affecting the growth of the tested shrimp,accompanied by improved immuneenzyme activity and changed expression of immune related genes,however,too high substitution can cause excessive stress response.