酵母水解物对凡纳滨对虾生长性能、肠道形态和血清非特异性免疫酶活性的影响

本试验旨在研究饲料中添加不同水平酵母水解物对凡纳滨对虾生长性能、肠道形态和血清非特异性免疫酶活性的影响。选择初始体重为(0.41±0.01)g的凡纳滨对虾幼虾640尾,随机分为4组(每组4个重复,每个重复40尾),酵母水解物的添加水平分别为0(对照组)、0.5%、1.0%、2.0%,共配制出4种等氮(42%粗蛋白质)等脂(8%粗脂肪)的试验饲料。进行为期8周的养殖试验。结果表明:1)各添加组的成活率、增重率和特定生长率与对照组相比,差异不显著(P0.05)。1.0%添加组增重率和特定生长率显著高于2.0%添加组(P0.05),而饲料系数显著低于2.0%添加组(P0.05)。1.0%添加组肝体比显著高于对照组(P0.05),各组肥满度没有显著性差异(P0.05)。2)饲料中添加不同水平酵母水解物对全虾以及肌肉的干物质、粗蛋白质、粗脂肪和粗灰分含量无显著性影响(P0.05)。3)酵母水解物对肠道的皱襞宽度、微绒毛高度和上皮细胞高度影响不显著(P0.05)。而2.0%添加组的肠道皱襞高度显著高于0.5%添加组(P0.05)。4)与对照组相比,添加1.0%的酵母水解物显著提高了血清酚氧化酶(PO)和溶菌酶(LZM)活性(P0.05),且一氧化氮合成酶(NOS)活性也在1.0%添加组达最大值。综上所述,在饲料中添加1.0%的酵母水解物能提高凡纳滨对虾的血清非特异性免疫酶活性,同时对生长性能和肠道形态健康不会产生负面影响。

Effects of Yeast Hydrolysate on Growth Performance,Intestinal Morphology and Serum Nonspecific Immune Enzyme Activities of Litopenaeus vannamei

This experiment was conducted to estimate the effects of dietary supplemental levels of yeast hydrol-ysate on growth performance, intestinal morphology and serum nonspecific immune enzyme activities of Litopenaeus vannamei. A total of 640 juvenile Litopenaeus vannamei with an initial average body weight of (0.40±0.01) g were randomly divided into four groups with four replicates and 40 Litopenaeus vannamei per replicate. Four isonitrogenous and isolipidic practical diets (42% crude protein and 8% crude lipid) were pre-pared by adding 0 ( control group) , 0. 5%, 1. 0% and 2. 0% yeast hydrolysate in a basal diet, respectively. The experiment lasted for 8 weeks. The results showed as follows:1) there were no significant differences in survival rate ( SR) , weight gain rate ( WGR) and specific growth rate ( SGR) between experimental groups and control group (P>0.05). 1.0% supplemental group had significantly higher WGR and SGR than 2.0%supplemental group ( P<0.05) , and significantly lower feed conversion ratio ( FCR) than 2.0% supplemental group (P<0.05). Hepatopancreas somatic index (HSI) in 1.0% supplemental group was significantly higher than that in control group ( P<0.05) , but condition factor ( CF) was not significantly affected by yeast hydrol-ysate supplementation ( P>0.05) . 2) Dietary supplemental level of yeast hydrolysate had no significant influ-ences on dry matter, crude protein, crude lipid and ash contents of whole shrimp and shrimp muscle ( P>0.05). 3) Fold width, microvillus height and enterocyte height of shrimp intestine were not significantly affect-ed by dietary supplementation of yeast hydrolysate (P>0.05). 2.0% supplemental group had a significantly higher fold height in intestine than in 0.5% supplemental group ( P<0.05) . 4) Compared with control group, serum activities of phenoloxidase ( PO) and lysozyme ( LZM) of shrimp were significantly increased by dieta-ry supplementation of 1.0% yeast hydrolysate (P<0.05), and serum nitric oxidesynthase (NOS) activity reached the maximum in 1.0% supplemental group. In conclusion, dietary supplementation of 1.0% yeast hy-drolysate can significantly increase serum nonspecific immune enzyme activities of Litopenaeus vannamei, and will not exert negatively affect growth performance and intestinal morphology health of Litopenaeus vannamei.