乙醇梭菌蛋白替代鱼粉饲料中添加姜黄素对凡纳滨对虾生长、免疫及肠道健康的影响

Effects of replacement of fish meal with Clostridium autoethanogenum protein and curcumin supplement in feed on growth, immunity and intestinal health of Litopenaeus vannamei

  • 摘要: 【目的】 探究乙醇梭菌蛋白替代鱼粉饲料中添加姜黄素对凡纳滨对虾生长、免疫及肠道健康的影响,为姜黄素和乙醇梭菌蛋白在凡纳滨对虾饲料中的合理应用提供理论依据。【方法】 选取480尾健康且规格一致的凡纳滨对虾幼虾,随机分为4组,分别投喂基础饲料(FM组)、乙醇梭菌蛋白替代70%鱼粉的低鱼粉饲料(LFM组)、添加0.006%姜黄素的低鱼粉饲料(LC1组)、添加0.012%姜黄素的低鱼粉饲料(LC2组)。养殖8周后,测定各处理组凡纳滨对虾的生长性能、血清生化指标和肠道消化酶活性,观察肠道形态并分析肠道菌群组成。【结果】 与FM组相比,LFM组凡纳滨对虾的终末体质量、增重率和特定生长率均显著降低(P<0.05,下同),饲料系数显著升高;与LFM组相比,LC1组和LC2组的终末体质量、增重率及特定生长率均显著升高,饲料系数显著降低,且除饲料系数外LC1组的各项生长性能指标优于LC2组。LFM组凡纳滨对虾血清中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和肠道中淀粉酶、蛋白酶活性均显著低于FM组,血清中丙二醛(MDA)含量和溶菌酶(LYS)活性较FM组显著升高;相较于LFM组,LC1组和LC2组MDA含量显著降低,SOD和CAT活性均显著升高;LC1组的蛋白酶和淀粉酶活性较LFM组显著升高。观察肠道切片发现,LFM组的肠绒毛趋于扁平化,部分上皮细胞脱落,上皮细胞高度与FM组相比明显降低;LC1组和LC2组的肠道形态较LFM组有较大改善。Alpha多样性分析结果表明,LC1组的凡纳滨对虾肠道菌群ACE和Chao1指数均高于FM组及LFM组。与LFM组相比,LC1组的肠道菌群变形菌门(Proteobacteria)和蓝藻门(Cyanobacteria)相对丰度显著降低,拟杆菌门(Bacteroidota)和放线菌门(Actinobacteriota)相对丰度显著升高,鲁杰氏菌属(Ruegeria)相对丰度升高,弧菌属(Vibrio)相对丰度显著降低。【结论】 乙醇梭菌蛋白高水平替代鱼粉会造成凡纳滨对虾生长性能下降,并影响机体免疫功能和肠道健康,添加适量姜黄素能提高凡纳滨对虾肠道菌群多样性,增加有益菌并减少有害菌,有效缓解乙醇梭菌蛋白高水平替代造成的肠道损伤,改善肠道健康,从而提高凡纳滨对虾的免疫能力和生长性能。

     

    Abstract: 【Objective】 To investigate the effects of high-level replacement of fish meal with Clostridium autoethanogenum protein(CAP) and curcumin(CUR) supplement on the growth, immunity and intestinal health of Litopenaeus vannamei, which could provide research basis for the rational application of CUR and CAP in the feed of Litopenaeus vannamei. 【Method】 A total of 480 healthy juvenile Litopenaeus vannamei of uniform size were selected and randomly divided into 4 groups, which were fed basal feed(FM group), low fish meal feed with 70% fish meal replaced by CAP(LFM group), low fish meal diet supplemented with 0.006% CUR(LC1 group), and low fish meal diet supplemented with 0.012% CUR(LC2 group) respectively. After 8 weeks of culture, the growth performance, serum biochemical indexes and intestinal digestive enzyme activities of Litopenaeus vannamei in each treatment group were measured, intestinal morphology was observed, and the composition of intestinal microbiota was analyzed. 【Result】 Compared with FM group, the final body weight, weight gain rate and specific growth rate of Litopenaeus vannamei in LFM group decreased significantly(P<0.05, the same below), and the feed coefficient rate increased significantly. Compared with the LFM group, Litopenaeus vannamei in the LC1 and LC2 groups exhibited significantly increased final body weight, weight gain rate and specific growth rate, along with a significantly decreased feed coefficient rate; moreover, except feed coefficient rate, the LC1 group demonstrated better overall growth performance indexes than the LC2 group. The activities of superoxide dismutase(SOD) and catalase(CAT) in serum as well as amylase and protease in the intestine of Litopenaeus vannamei in the LFM group were significantly lower than those in the FM group, whereas malondialdehyde(MDA) content and lysozyme(LYS) activity in serum were significantly higher than those in the FM group. Compared with the LFM group, the MDA content in LC1 group and LC2 group was significantly decreased, and the activities of SOD and CAT were significantly increased. The protease and amylase activities in LC1 group were significantly higher than those in LFM group. Observation of intestinal sections showed that the intestinal villus folds in the LFM group tended to be flat and disappeared, and some epithelial cells fell off. The epithelial cell height was greatly lower than those in the FM group. The intestinal morphology of the LC1 group and the LC2 group was greatly improved compared with the LFM group. The results of Alpha diversity analysis showed that the ACE and Chao1 indexes of intestinal microbiota in LC1 group were higher than those in FM group and LFM group. Compared with the LFM group, the LC1 group showed significantly decreased relative abundance of Proteobacteria and Cyanobacteria, but significantly increased relative abundance of Bacteroidota and Actinobacteriota in the intestinal microbiota. Additionally, the relative abundance of Ruegeria increased, while that of Vibrio decreased significantly. 【Conclusion】 Replacement of fish meal with CAP can cause a decrease in the growth performance of Litopenaeus vannamei, and affect the body’s immunity and intestinal health. Adding an appropriate amount of CUR can enhance the diversity of the intestinal flora of Litopenaeus vannamei, increase beneficial bacteria and reduce harmful ones, effectively alleviate intestinal damage caused by high-level replacement of CAP, improve intestinal health, and thereby enhance the immune capacity and growth performance of Litopenaeus vannamei.

     

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