脆化养殖对罗非鱼生长、血清生化指标及肠道健康的影响

Effects of crisp culture on growth performance，serum biochemical indexes and intestinal health of tilapia（Orechromis niloticus）

摘要:

为评价脆化养殖对罗非鱼（Oreochromis niloticus）生长、血清生化指标及肠道健康的影响，分别用蚕豆、脆化饲料（约含50%蚕豆）和普通饲料饲喂罗非鱼[体质量为（665±34）g]，检测饲喂40和80 d后的罗非鱼生长、血清生化、肠道组织形态、紧密连接蛋白、消化酶、抗氧化酶、炎性基因以及肠道菌群指标。结果表明：与普通饲料组相比，蚕豆组和脆化饲料组罗非鱼体质量、体长和增重率显著降低。蚕豆组血清溶菌酶（LYZ）显著增加，血清碱性磷酸酶（AKP）无显著差异，80 d血清谷草转氨酶（AST）和谷丙转氨酶（ALT）升高，脆化饲料组血清ALT、AST和AKP无显著差异，LYZ显著升高。蚕豆组和脆化饲料组肠绒毛长度均缩短。蚕豆组紧密连接蛋白基因Occludin、ZO-3和Claudin-3 表达显著下降，Claudin-12表达显著上升，脆化饲料组上述基因表达无显著差异。蚕豆组α-淀粉酶和脂肪酶活性减小，脆化饲料组仅40 d脂肪酶活性减小。蚕豆组丙二醛（MDA）含量显著增加，80 d总抗氧化能力（T-AOC）显著增加，脆化饲料组MDA含量无显著差异，T-AOC显著下降。蚕豆组和脆化饲料组促炎基因IFN-γ、TNF-α和抗炎基因IgM表达水平显著增加，蚕豆组抗炎基因TGF-β1和IL-10表达水平显著下降，脆化饲料组TGF-β1和IL-10显著增加。脆化饲料组肠道微生物ACE、Chao1、Simpson和Shannon指数和对照组接近且高于蚕豆组，脆化饲料组毛螺菌属、乳酪杆菌丰度下降，分枝杆菌、多种梭菌丰度增加，蚕豆组厚壁菌门、梭杆菌门和鲸蜡杆菌属丰度下降，变形菌门、分枝杆菌等丰度增加。与饲喂40 d相比，饲喂80 d时脆化饲料组中大部分指标无显著变化。用蚕豆或脆化饲料养殖罗非鱼均会抑制其生长和肠道抗氧化能力，使肠绒毛变短，引起肠道炎症反应，使肠道有益菌丰度下降、潜在致病菌丰度增加，但脆化饲料对罗非鱼的不利影响弱于蚕豆，主要表现为脆化饲料对肠道消化酶活性、细胞膜通透性和抗炎系统无显著影响，蚕豆对上述指标均有显著负面影响。

Abstract:

To evaluate the effects of crisp culture on the growth， serum biochemical indexes and intestinal health of tilapia， Nile tilapia（Orechromis niloticus）（665±34） g were fed with faba bean， crisp feed （approximately 50% faba bean） and ordinary feed. The growth， serum biochemistry， intestinal tissue morphology， tight junction protein， digestive enzyme， antioxidant enzyme， inflammatory gene and intestinal flora of tilapia were investigated at 40 d and 80 d. The results showed that： The body mass/length and weight gain rate in the faba bean/crisp feed group were significantly lower than those in the ordinary feed group. The serum lysozyme （LYZ） in the faba bean group was significantly higher than that in the ordinary feed group. There was no significant difference in serum alkaline phosphatase （AKP） between the faba bean group and ordinary feed group. The serum aspartate aminotransferase （AST） and alanine aminotransferase （ALT） increased at 80 days in faba bean group. There was no significant difference in serum ALT， AST and AKP between the crisp feed group and ordinary feed group， whereas LYZ was significantly higher in the crisp feed group. The length of intestinal villi in the faba bean/crisp feed group was shorter than that in the ordinary feed group. The expressions of tight junction protein genes Occludin/ZO-3 /Claudin-3 decreased significantly and the expression of Claudin-12 increased significantlyin the faba bean group. There was no significant difference in the expressions of the above genes between the crisp feed group and ordinary feed group. The activities of α-amylase and lipase in faba bean group decreased， and the activity of lipase in crisped feed group decreased only at 40 d. The content of malondialdehyde （MDA） in faba bean group significantly increased， and the total antioxidant capacity （T-AOC） significantly increased at 80 d. There was no significant difference in MDA content between the crisp feed group and ordinary feed group， but T-AOC significantly decreased. The expressions of pro-inflammatory genes IFN-γ， TNF-α and anti-inflammatory gene IgM were significantly higher in the faba bean /crisp feed group than those in the ordinary feed group. The expressions of anti-inflammatory genes TGF-β1 and IL-10 decreased in the faba bean group， but the TGF-β1 and IL-10 significantly increased in crisp feed group. The ACE， Chao1， Simpson and Shannon indexes of intestinal microorganisms in the crisped feed group were close to those in the ordinary feed group but higher than those in the broad bean group. The abundance of Lachnospiraceae and Lactobacillus in the crisped feed group decreased， while the abundance of Mycobacteria and multiple Clostridium increased. The abundance of Firmicutes， Fusobacteria and Cetobacterium in the broad bean group decreased， whereas the abundance of Proteobacteria and Mycobacteria increased. Compared with 40 d， there were no significant changes in most indexes in the crisp feed group at 80 d. In conclusion， feeding tilapia with faba bean or crisp feed （approximately 50% faba bean） inhibited growth and intestinal antioxidant capacity， shortened intestinal villi， induced intestinal inflammatory reactions， reduced the abundance of beneficial bacteria and increased the abundance of pathogenic bacteria in the intestine. However， the adverse effects of crisp feed were weaker than those of faba bean. The crisp feed had no significant effect on intestinal digestive enzyme activity， cell membrane permeability and anti-inflammatory system. Faba bean had significant negative effects on the above indexes.