谷氨酰胺对杂交罗非鱼生长、饲料利用及抗病力的影响

Effects of dietary glutamine on growth performance, feed utilization and anti-disease ability of hybrid tilapia (Oreochromis niloticus♀×O.aureus♂)

以初始体质量为(9.87±0.20)g的全雄奥尼罗非鱼(Oreochromis niloticus♀×O.aureus♂)为实验对象,研究饲料中不同水平谷氨酰胺对奥尼罗非鱼生长、饲料利用及抗病力的影响。实验共设6个处理组,每组谷氨酰胺添加量分别为饲料质量的0、0.2%、0.4%、0.6%、0.8%和2.0%,各设3个平行。用开放式流水养殖,饲养8周。之后注射嗜水气单胞菌(Aeromonas hydrophila)进行感染实验,观察7d,计算成活率。结果表明,饲料中添加谷氨酰胺对杂交罗非鱼的增重率、特异生长率、成活率及饲料系数均无显著影响(P>0.05),但对蛋白效率和蛋白质沉积率影响显著(P<0.05)。添加量为0.6%和0.8%组的蛋白质效率显著高于添加量为0～0.4%组(P<0.05),其余各组间差异不显著(P>0.05)。蛋白质沉积率则以添加0.8%组最高,显著高于添加量为0～0.4%组(P<0.05),其余各组间差异不显著(P>0.05)。谷氨酰胺对杂交罗非鱼的肥满度和脾体比有显著影响(P<0.05),但对肝体比和头肾体重比则影响不显著(P>0.05)。用嗜水气单胞菌分别攻毒48h、72h和96h,谷氨酰胺0.6%～0.8%饲料组罗非鱼的存活率影响显著高于0～0.4%组(P<0.05);而对攻毒后1h及24h的存活率各添加组间无显著影响(P>0.05)。综上结果,建议奥尼罗非鱼配合饲料中谷氨胺酰胺的适宜添加水平为0.6%～0.8%。

This study was conducted to determine the effects of glutamine with different dietary supplementation levels （0,0.2%, 0.4%, 0.6%, 0.8% and 2.0%） on growth performance, feed utilization, body composition and anti-disease ability of juvenile hybrid tilapia（Oreochromis niloticus ♀×O. aureus ♂）for 8 weeks. Six iso- nitrogenous and iso-energic diets were formulated as experimental diets. The results showed that the diet with glutamine supplementation significantly increase the protein efficiency ratio （PER）and productive protein value （PPV） （P〈0.05）, but could not significantly increase the weight gain rate （WG）, specific growth rate （SGR）, feed convention ratio （FCR） and survival rate of juvenile tilapia （P〉0.05）. The whole condition factor （CF）and spleen body index （SBI）were significantly affected by the dietary glutamine supplementation levels （P〈0.05）, while there was no significant effect of glutamine supplementation levels on hepatopancrease body index （HBI） and head kidney body index （HKBI） （P〉0.05）. There were significant differences （P〈0.05） in moisture and protein content of whole body, but the variations were not marked （P〉0.05） in lipid and ash contents of whole body. The challenge trial was done by intraperitoneal （i.p.）injection ofAeromonas hydrophila at a concentration of 0.2 mL/ind （LD50 around 10^7 CFU/mL）. The control group （non- infective group）was injected i.p. with 0.2 mL at 0.9% NaCI per fish. The survival rates of 48 h, 72 h and 96 h after challenge against A. hydrophila were significantly affected by the dietary glutamine supplementation levels （P〈0.05）, but survival rate at 1 h and 24 h were not affected （P〉0.05）. Based on PER, PPV and survival rate after challenge against A. hydrophila, the optimal dietary supplementation levels of glutamine for this diet formulation was 0.6%-0.8%. [Journal of Fishery Sciences of China, 2008, 15 （6） ： 1 016-1 023]