发酵软颗粒饲料对凡纳滨对虾生长性能、血清指标、肝胰腺和肠道形态以及肠道菌群的影响

Effects of Fermented Soft Pellet Feed on Growth Performance, SerumIndices, Hepatopancreas and Intestine Morphology and IntestinalFlora of Pacific White Shrimp ( Litopenaeus vannamei )

本试验旨在研究发酵软颗粒饲料对凡纳滨对虾生长性能、血清指标、肝胰腺和肠道形态以及肠道菌群的影响。选用300只健康、规格一致[(3.35±0.08)g]的凡纳滨对虾,随机分成2组,每组3个重复,每个重复50只。对照组饲喂基础饲料,试验组饲喂用发酵软颗粒饲料替代5%基础饲料的试验饲料。发酵软颗粒饲料以配合颗粒饲料为发酵底物,利用由鼠李糖乳杆菌(Lactobacillus rhamnosus)、枯草芽孢杆菌(Bacillus subtilis)、酿酒酵母(Saccharomyces cerevisiae)和索氏鲸杆菌(Cetobacterium somerae)复配的发酵菌剂进行发酵制备而成。试验期6周。结果表明:1)与对照组相比,试验组凡纳滨对虾增重率、特定生长率和成活率显著提高(P<0.05),饲料系数显著降低(P<0.05)。2)与对照组相比,试验组凡纳滨对虾血清酸性磷酸酶和溶菌酶活性显著提高(P<0.05),血清丙二醛含量显著降低(P<0.05)。3)肝胰腺切片观察显示,试验组凡纳滨对虾肝胰腺中肝小体排列紧密,肝小体之间基底膜完整,B细胞和R细胞数量较为丰富;而对照组肝胰腺中肝小体排列松散,基底膜脱落,B细胞有损伤,R细胞和E细胞数量减少。中肠切片观察显示,试验组肠上皮细胞游离面的绒毛排列更为整齐、紧密,且绒毛高度明显高于对照组。4)主坐标分析(PCoA)和非度量多维尺度(NMDS)分析结果显示,试验组凡纳滨对虾肠道菌群与对照组有显著差异(P<0.05)。菌群组成分析表明,与对照组相比,试验组肠道未分类_f_红杆菌科(unclassified_f_Rhodobacteraceae)和鲁杰氏菌属(Ruegeria)的相对丰度有所提高,肠道未分类_f_黄杆菌科(unclassified_f_Flavobacteriaceae)的相对丰度有所降低。综上所述,发酵软颗粒饲料能够提高凡纳滨对虾生长性能,增强免疫力,调节肠道菌群组成,维持肝胰腺和肠道健康。

This experiment was conducted to investigate the effects of fermented soft pellet feed on growth performance,serum indices,hepatopancreas and intestine morphology and intestinal flora of Litopenaeus vannamei.Three hundred healthy Litopenaeus vannamei with the same specifications of(3.35±0.08)g were randomly divided into 2 groups with 3 replicates per group and 50 shrimp per replicate.The control group was fed the basal diet,and the experimental group was fed the experimental diet in which 5%of the basal diet was replaced by fermented soft pellet feed.Fermented soft pellet feed was prepared by fermentation using Lactobacillus rhamnosus,Bacillus subtilis,Saccharomyces cerevisiae and Cetobacterium somerae as mixed fermentation agent and pellet feed as fermentation substrate.The trial lasted for 6 weeks.The results showed as follows:1)compared with the control group,the weight gain rate,specific growth rate and survival rate of Litopenaeus vannamei in experimental group were significantly increased(P<0.05),and the feed coefficient was significantly decreased(P<0.05).2)Compared with the control group,the activity of acid phosphatase and lysozyme in serum of Litopenaeus vannamei in experimental group was significantly increased(P<0.05),and the malondialdehyde content in serum was significantly decreased(P<0.05).3)Hepatopancreas section observation showed that the hepatopancreas of Litopenaeus vannamei in experimental group was closely arranged,the basement membrane between the hepatopancreas was intact,and the number of B and R cells was abundant;however,in the control group,the hepatopancreas was arranged loosely,the basement membrane was shed,B cells were damaged,and the number of R and E cells was reduced.The observation of midgut section showed that the villi on the free surface of intestinal epithelial cells in experimental group were arranged more neatly and closely,and the villus height was significantly higher than that in the control group.4)The results of principal coordinate analysis(PCoA)and non-metric multidimensional scale(NMDS)analysis showed that the intestinal flora of Litopenaeus vannamei in experimental group was significantly different from that in the control group(P<0.05).The bacterial community composition analysis showed that compared with the control group,the relative abundances of intestinal unclassified_f_Rhodobacteraceae and Ruegeria in experimental group were increased,and the relative abundance of intestinal unclassified_f_Flavobacteriaceae was decreased.In conclusion,the fermented soft pellet feed can improve growth performance,enhance immunity,regulate intestinal flora and maintain hepatopancreas and intestine health of Litopenaeus vannamei.