聚β-羟基丁酸酯对凡纳滨对虾肝胰腺免疫和消化指标的影响

以平均体质量为(5.66±0.14)g的凡纳滨对虾(Litopenaeus vannamei)为研究对象,分别投喂含聚β-羟基丁酸酯(PHB)质量分数为0%(对照组)、1%、3%和5%的对虾配合饲料,饲养35 d后检测并比较不同水平PHB对凡纳滨对虾肝胰腺免疫和消化指标的影响。结果显示,3%PHB添加组凡纳滨对虾的总抗氧化能力和溶菌酶活性显著高于对照组(P0.05)。Toll基因表达量随PHB含量的升高呈先上升后下降趋势,其中1%和3%PHB添加组的表达量显著高于对照组(P0.05);对照组HSP70基因表达量显著低于其他处理组(P0.05)。5%PHB添加组的淀粉酶、胃蛋白酶和胰蛋白酶活性显著升高(P0.05),而脂肪酶活性无显著变化(P0.05)。由此可见,饲料中添加适量的PHB有利于增强凡纳滨对虾肝胰腺的消化和非特异性免疫能力。

Effects of poly-β-hydroxybutyrate (PHB) on immune and digestive indicators in hepatopancreas of Litopenaeus vannamei

Litopenaeus vannamei of average weight of (5.66 ± 0.14) g had been fed for 35 d with four different diets:0％,1％,3％ and 5％ poly-β-hydroxybutyrate (PHB) supplemented feed,and the immune and digestive indicators in hepatopancreas of shrimp were evaluated in this study.The results show that compared with the control group,the shrimps in 3％ PHB group had higher total antioxidant capacity (T-AOC) and lysozyme (LSZ) activity (P ＜ 0.05).The relative expression level of Toll gene increased but then decreased with increasing PHB content,and the expression levels in 1％ and 3％ PHB groups were higher than that in the control group significantly (P ＜ 0.05).The relative expression levels of heat shock protein 70 (HSP70) gene in all three PHB treatment groups were higher than that in the control group significantly (P ＜ 0.05).The amylase,pepsin and trypsin activities of 5％ PHB group were significantly higher than those of the control group (P ＜ 0.05),but the lipase activity showed no significant difference (P ＞0.05).It is indicated that appropriate PHB content in diet can improve the immune and digestive abilities in hepatopancreas of shrimps significantly.