饲料中添加杜仲叶粉对青鱼生长和组织免疫相关基因表达的影响研究

Effects of dietary Eucommia ulmoides Oliver leaf powder on the growth performance and expression of immunity related genes in Mylopharyngodonpiceus

在基础日粮中(对照组)分别添加2.5%、5.0%、7.5%的杜仲叶粉在湖泊养殖网箱饲养青鱼60 d后,分别测定各处理青鱼的尾增重、相对增重率、饲料系数、肥满度等生长指标,以β-actin为内参研究基因免疫球蛋白M(Ig M)、白介素-1β(IL1β)、主要组织相容性复合物(MHC I、MHC II)、肿瘤坏死α因子(TNFα)和补体C3六个免疫功能基因在青鱼肝、肾、肠和肌肉组织中的表达差异性,探讨饲料中添加不同剂量的杜仲叶粉对青鱼生长性能以及组织免疫相关基因表达的影响。结果表明:添加7.5%杜仲叶粉组的青鱼相对增重率提高29.26%(P<0.01),饲料系数降低22.73%(P<0.01),且显著增加肥满度(P<0.05)。添加2.5%、5.0%杜仲叶粉也有提高尾增重、相对增重率、肥满度,降低饲料系数等作用,但效果不如7.5%添加量显著。Ig M、MHC I、MHC II、TNFα、IL1β以及补体C3基因肾中的各基因表达差异显著(P<0.05);肝中IL1β、MHC II、TNFα和C3基因表达也有明显差异;肠和肌肉中的各基因表达量无显著差异(P>0.05)。研究结果揭示了基础饲料中添加7.5%杜仲叶粉能显著促进青鱼鱼种的生长性能,并提高其免疫功能。

Pen-culture was employed to conduct the present Mylopharyngodonpiceu feeding experiment, by adding different doses of Eucommla ulmoides Oliver leaf powder in the basic diet （control group） as 2.5%, 5.0% and 7.5%, respectively. Each treatment contains 6 replicates, and each replicate contains 20 fishes. After 60 d feeding, six fishes of each treatment were randomly selected for analysis. We measured the growth performance of tail weight, relative weight gain, feed conversion rate and fatness; detected the mRNA expression levels of immunity related genes including the immunoglobulin gene M （IgM）, interleukin -β （IL1β）, major histocompatibility complex （MHC I, MHC II）, tumor necrosis factor α （TNFα and complement C3 in liver, kidney, intestine and muscle tissues, to study the effect of different content of dietary Eucommia ulrnoides Oliver leaf powder on the growth and immune-related gene expression of Mylopharyrtgodonpiceus. The results showed that, adding 7.5% Eucommla ulmoides Oliver leaf powder group could significantly increase the relative growth rate by 29.26% （P〈0.01）, reduce feed conversion ratio 22.73% （P〈0.01）, and markedly increase fatness （P〈0.05）. Adding 2.5% or 5.0% also improved tail weight gain, relative growth rate, fatness, and reduced the feed conversion ratio, but the effect of those groups was less than the 7.5% group. IgM, IL1β , MHCI, MHC II, TNFα , C3 gene expression levels were significantly enhanced in kidney （P〈0.05）, and IL1β in liver, but tendency of MHC II, TNFα and C3 gene expression levels were obviously different. Additionally, there were nosignificant differences of the gene expression levels among all the groups in the tissue of intestinal and muscle. Those results suggested that dietary content of 7.5% Eucommia ulmoides Oliver leaf powder could significantly promote the growth performance and immune function of herring species.