日粮中添加桑叶提取物和1-脱氧野尻霉素对大鲵生长、消化、免疫能力和肠道菌群的影响

EFFECTS OF DIETARY MULBERRY LEAF EXTRACT AND 1-DEOXYNOJIRIMYCIN ON GROWTH,DIGESTION AND IMMUNITY CAPACITY,AND INTESTINAL MICROORGANISM OF CHINESE GIANT SALAMANDER(ANDRIAS DAVIDIANUS)

为探究桑叶物提取物(MLE)和单体1-脱氧野尻霉素(DNJ)对大鲵(Andrias davidianus)生长、消化、免疫能力和肠道菌群影响的差异,研究以基础饲料为对照组,分别添加0.75%的MLE和0.04‰的DNJ制成3种等氮等脂的饲料,饲喂初始均重为(47.81±0.23)g的大鲵90d。结果:MLE组和DNJ组增重率和饲料效率显著提高(P<0.05);肠道脂肪酶和胰蛋白酶活力显著提高(P<0.05),肠道丙二醛、血浆内毒素显著降低(P<0.05),肠黏膜绒毛数量显著增加(P<0.05),肠黏膜上皮细胞间紧密连接更加紧密;与对照组相比,MLE组雷帕霉素靶蛋白(Target of rapamycin,TOR)、白细胞介素-10(Interleukin,IL-10)、多聚免疫球蛋白受体(Polymeric immunoglobulin receptor,pIgR)、类Toll受体2(Toll-like receptor 2,TLR2)和髓样分化初级反应基因88(Myeloid differentiation primary response gene88,MyD88)mRNA表达水平显著上调(P<0.05),DNJ组pIgR mRNA表达水平显著上调(P<0.05);肠道菌群中瘤胃球菌科细菌丰度降低,Romboutsia丰度增加,肠道微生物多样性较对照组提高(P<0.05)。与DNJ组相比,MLE组和DNJ组增重率和饲料效率无显著差异(P>0.05),MLE组胃蛋白酶、H~+-K~+-ATP酶和Na~+-K~+-ATP酶活力显著提高,肠道总抗氧化能力显著提高(P<0.05),肠黏膜上皮细胞紧密连接程度提高,肠绒毛高度显著增加(P<0.05),血浆内毒素含量显著降低。结果表明,在大鲵配合饲料中添加MLE和DNJ均能不同程度改善大鲵胃和肠的消化吸收功能,提高生长性能、肠道抗氧化能力和免疫能力,提高肠道微生物多样性,促进肠道发育;综合胃和肠结构和功能,复合MLE较单体DNJ效果更优。

This study explored the effects of feeding basal diet,mulberry leaf extract diet(containing 0.75%MLE)and 1-deoxynojirimycin diet(containing 0.04‰DNJ)on growth,digestion and immunity capacity,and intestinal microorganism in giant salamanders for a 90-day trail.Giant salamanders with an initial body weight of(47.81±0.23)g were randomly divided into 3 groups for these 3 diets.Compared with the control diet,the weight gain rate and feed efficiency in MLE and DNJ groups were significantly improved(P<0.05);lipase and trypsin activities were also significantly increased(P<0.05).The contents of endotoxin in plasma acid and malondialdehyde in intestine in MLE and DNJ groups were significantly lower than those in control group(P<0.05).Compared with control group,the number of intestinal villi in MLE and DNJ groups were increased,and the tight junction between intestinal mucosa cells in MLE and DNJ groups were closer.Compared with the control group,the mRNA expression levels of target of rapamycin(TOR),interleukin-10(IL-10),polymeric immunoglobulin receptor(pIgR),toll-like receptor-2(TLR2)and myeloid differentiation primary response gene88(MyD88)in MLE group were significantly increased(P<0.05),and the mRNA expression level of pIgR in the DNJ group was significantly increased(P<0.05).The diversity of intestinal bacteria in MLE and DNJ group was higher than that in control group.There was no significant difference in weight gain rate and feed efficiency among 3 groups(P>0.05);MLE group significantly increased the activities of pepsin,H+-K+-ATPase,Na+-K+-ATPase and the total intestinal antioxidant capacity compared with the control group(P<0.05).In addition,MLE group had closer tight junction between intestinal mucosa cells,higher intestinal villi height(P<0.05),and lower plasma endotoxin content(P<0.05),compared with DNJ group.In summary,MLE and DNJ can improve growth performance,digestion and absorption functions,intestinal antioxidant and immune capabilities,promote the growth of beneficial bacteria in the intestine,increase the diversity of intestinal microorganisms,and promote the intestinal development of the giant salamander.Combined the structure and function of the stomach and intestines,MLE is more effective than DNJ.