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本实验旨在研究外源核苷酸混合物对凡纳滨对虾(Litopenaeus vannamei)幼虾生长性能、体组成、中肠肠道形态和抗氧化酶活力的影响。选取960尾初始体质量为(1.01±0.02)g的凡纳滨对虾,随机分为8组,分别投喂基础饲料和添加5种核苷酸混合物(5′-腺苷酸∶5′-胞苷酸∶5′-尿苷酸二钠∶5′-肌苷酸二钠∶5′-鸟苷酸二钠=1∶1∶1∶1∶1,mix-NT)的实验饲料,各实验组添加量分别为0.1、0.2、0.4、0.6、0.8、1.0和1.2 g/kg饲料,养殖期为7周。结果显示,饲料中添加5种核苷酸混合物对凡纳滨对虾的特定生长率(SGR)和饲料系数(FCR)影响不显著(P>0.05)。外源核苷酸显著影响凡纳滨对虾全虾水分含量(P<0.05),但对全虾粗蛋白、粗脂肪和灰分含量影响不显著(P>0.05)。肝胰指数(HSI)随饲料中核苷酸添加量的增加而显著升高(P<0.05),在0.6 g/kg组达到最高。0.4 g/kg组的肝胰腺谷草转氨酶(GOT)和谷丙转氨酶(GPT)活力及尿酸(UA)含量最低,但与对照组相比差异均不显著(P>0.05)。中肠肠壁厚度和肠绒毛高度均随着核苷酸添加量的增加呈先升高后降低的趋势,其中添加量为0.1～0.8 g/kg组的肠壁厚度显著高于其他组(P<0.05);各组间的肠绒毛高度无显著性差异(P>0.05)。饲料中添加核苷酸混合物可显著提高凡纳滨对虾肝胰腺碱性磷酸酶(AKP)活力和总抗氧化能力(T-AOC)(P<0.05),两者的最高值分别出现在0.2 g/kg组和0.4 g/kg组。各添加组血清碱性磷酸酶(AKP)和超氧化物歧化酶(SOD)活力与对照组相比差异均不显著(P>0.05)。结果表明,饲料中添加一定量的5种核苷酸混合物有助于改善凡纳滨对虾肠道形态,增强机体的抗氧化能力。
The aim of this experiment was to investigate the effects of exogenous nucleotide mixtures on growth performance, body composition, intestinal morphology and antioxidant enzyme activities in shrimp Litopenaeus vannamei. Nine hundred and nine P. vannamei individuals with initial body mass of (1.01 ± 0.02) g were randomly divided into 8 groups and fed with basal diet and 5 nucleotide mixtures (5’-adenylate: 5’-cell Nucleotide: disodium 5’-uridylate: disodium 5’-inosinate: disodium 5’-guanylate = 1: 1: 1: 1: 1, mix-NT) The dosage of group was 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 g / kg respectively, and the culture period was 7 weeks. The results showed that there was no significant difference (P> 0.05) in the specific growth rate (SGR) and feed conversion coefficient (FCR) between five nucleotide mixtures. Exogenous nucleotide significantly affected the water content of whole shrimp (P <0.05), but had no significant effect on the crude protein, crude fat and ash content of whole shrimp (P> 0.05). Hepatic pancreatic index (HSI) increased significantly with the addition of nucleotide in feed (P <0.05), and reached the peak at 0.6 g / kg. The activities of GOT and GPT and the content of uric acid (UA) of 0.4 g / kg group were the lowest, but there was no significant difference compared with the control group (P> 0.05). Intestinal wall thickness and intestinal villus height increased first and then decreased with the increase of nucleotide addition. The thickness of intestinal wall in 0.1-0.8 g / kg group was significantly higher than that in other groups (P <0.05). There was no significant difference in intestinal villus height between groups (P> 0.05). The addition of nucleotide mixture to feed significantly increased hepatopancreas alkaline phosphatase (AKP) activity and total antioxidant capacity (T-AOC) (P <0.05), both of which appeared at 0.2 g / kg group and 0.4 g / kg group. The activities of serum alkaline phosphatase (AKP) and superoxide dismutase (SOD) in each added group were not significantly different from those in the control group (P> 0.05). The results showed that adding a certain amount of 5 kinds of nucleotide mixture to the feed could help to improve the intestinal morphology of Litopenaeus vannamei and enhance the body’s antioxidant capacity.