低鱼粉饲料中添加低分子水解鱼蛋白对凡纳滨对虾非特异性免疫力和抗氧化能力的影响

Effects of Dietary Low-Molecular-Weight Fish Hydrolysate (LWFH) on Nonspecific Immunity and Antioxidant Capacity of Pacific White Shrimp (Litopenaeus vannamei)

中文关键词: 凡纳滨对虾  鱼粉替代  水解鱼蛋白  非特异免疫  抗病基因

英文关键词: Litopenaeus vannamei  Replacement of fishmeal  Fish hydrolysate  Nonspecific immunity  Resistance gene

中文摘要:

      以鱼粉水平为30%的饲料为高鱼粉饲料对照组，以豆粕替代高鱼粉饲料中50%鱼粉形成低鱼粉基础饲料，低鱼粉基础饲料添加0、0.5%、1.0%、1.5%和2.0%低分子水解鱼蛋白，配制 6种实验饲料，对初始体重为(0.44±0.02) g的凡纳滨对虾(Litopenaeus vannamei)幼虾进行48 d的养殖实验。实验结束后采集样品，测定肝胰腺酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、总超氧化物歧化酶(T-SOD)活力和丙二醛(MDA)含量，并分析肠道先天免疫缺陷基因(IMD)、对虾素3a分子(Penaiedin 3a)、溶菌酶(LZM)和Crustin相关免疫基因的表达量，以探讨低分子水解鱼蛋白对凡纳滨对虾非特异性免疫力和抗氧化能力的影响。结果显示，在低鱼粉饲料中添加适宜水平的低分子水解鱼蛋白能够显著提高对虾肝胰腺T-SOD、AKP和ACP的活力，降低MDA的含量；且1.5%低分子水解鱼蛋白能增加IMD、Penaiedin 3a、LZM和Crustin基因表达量。综上，凡纳滨对虾非特异免疫力和抗氧化能力的降低可能是影响植物蛋白源替代鱼粉的关键原因之一，而在饲料中补充1.0%–1.5%的低分子水解鱼蛋白可有效提高凡纳滨对虾抗病相关基因的表达量，增强其非特异免疫力和抗氧化能力。

英文摘要:

      In this study we investigated effects of low-molecular-weight fish hydrosate (LWFH) on nonspecific immune and antioxidant capacity in the hepatopancreas and the expression of some immunity-related genes in the digestive tract of Pacific white shrimp (Litopenaeus vannamei). A diet containing 30% of fishmeal was regarded as a high fishmeal diet (HFM), and a diet containing soybean meal that substitutes 50% of the fishmeal in HFM was considered as a low fishmeal basal diet (LFM). Five LFM diets were formulated by adding LWFH at incremental levels (0, 0.5%, 1.0%, 1.5% and 2.0%) to LFM, which were designated as LFM0, LFM0.5, LFM1.0, LFM1.5, and LFM2.0, respectively. The experimental diets were fed to L. vannamei of (0.44±0.02) g in a water recirculation system for 48 days. The nonspecific immunity and antioxidant indices, and the activities of acid phosphatase (ACP), alkaline phosphatase (AKP), total superoxide dismutase (T-SOD) and the content of malonaldehyde (MDA) in the hepatopancreas were measured to determine the effects of dietary LWFH. We studied the expression of immunity-related genes including IMD, Penaiedin 3a, LZM and Crustin using qRT-PCR. The results suggested that a certain amount of LWFH could significantly improve the activities of ACP, AKP and T-SOD while reducing the content of MDA in the hepatopancreas. Moreover, the relative expression of IMD, Penaiedin 3a, LZM and Crustin were up-regulated in the LFM1.5 group. Therefore, the plant proteins may not be an ideal substitute because they may reduce the nonspecific immunity and antioxidant capacity of L. vannamei. Our results also suggested that 1.0%–1.5% LWFH added in LFM might increase the expression of the disease resistance related genes and enhance nonspecific immunity and antioxidant capacity．