Effects Of Dietary Yeast,Yeast RNA,β-Glucan, Yeast RNA And β-Glucan On Growth And Immune Performance Of Juvenile Tilapia (Oreochromis Niloticud)

In this experiment, four kinds of isonitrogenous and isoenergetic diets containing 0.2% yeast,0.04% yeast RNA,0.2%p-glucan and 0.04% RNA + 0.2% β-glucan were designed to juvenile tilapia (5.0±0.02g) for 56 days. This study explored the effects of yeast, yeast RNA, β-glucan, β-glucan and yeast RNA on the growth performance, serum immune parameters of juvenile tilapia. The results showed:1. In allexperimental group except for P-glucan group, the final body weight (FBW), feed intake (FI) and specific growth rate (SGR) were significantly increased compared with the control group, and the feed conversion ratio (FCR) was significantly lower (P<0.05). While in yeast RNA group, the FBW, FI and SGR were significantly higher and the FCR was significantly lower than other experimental groups (P<0.05), which indicated the better growth performance of tilapia fingerlings.2. Compared with control group, serum superoxide dismutase (SOD), catalase (CAT) of all experimental groups were significantly increased (P<0.05). The antioxidant capacity of tilapia fingerlings was significantly enhanced; besides, lysozyme (LZM) and acid phosphatase (ACP) were significantly increased compared with control group (P<0.05). While contents of four kinds of immune related enzyme in yeast RNA + β-glucan group were significantly higher than the other experimental groups (P<0.05).3. Compared with the control group, the serum total protein content, globulin content of yeast group, yeast RNA group, β-glucan group, yeast RNA + P-glucan group increased significantly, and the A/G ratio were significantly lower (P<0.05). yeast RNA with β-glucan group got the highest content of total protein, globulin and the lowest A/G ratio which were significantly different with other experimental groups (P<0.05). The experiment included that dietary yeast, yeast RNA, yeast RNA +β-glucan could improve the growth performance of tilapia fingerlings and supplement of 0.04% yeast RNA showed better promotion of the growth performance; Yeast, yeast RNA, β-glucan and yeast RNA + β-glucan could improve the immune performance of tilapia fingerlings, and supplement of 0.04% yeast RNA + 0.2 β-glucan showed best promotion of the immune performance.