牛磺酸及相关氨基酸对大菱鲆幼鱼生长性能及TauT mRNA表达的影响

EFFECTS OF DIETARY TAURINE AND RELATED AMINO ACIDS ON GROWTH PERFORMANCE AND TAURINE TRANSPORTER (TAUT) MRNA EXPRESSION OF JUVENILE TURBOT (SCOPHTHALMUS MAXIMUS L.)

以初始体重为(7.90±0.07)g的大菱鲆为实验对象,鱼粉、豆粕、玉米蛋白粉和谷朊粉为主要蛋白质来源,鱼油为主要脂肪源,在此基础配方中分别添加0、1%、2%牛磺酸,0.5%蛋氨酸及0.5%半胱氨酸(分别命名为T-0、T-1、T-2、M-0.5和C-0.5),配制5种等氮等脂的配合饲料,在室内流水养殖系统进行为期10周的养殖实验,目的是研究饲料中含有高比例植物蛋白时牛磺酸、蛋氨酸和半胱氨酸对大菱鲆幼鱼生长及牛磺酸转运载体(TauT)mRNA表达的影响。结果表明,与对照组相比,T-1、T-2组大菱鲆幼鱼的特定生长率(SGR)和饲料效率(FE)提高(P<0.05),内脏指数(VSI)降低(P<0.05);M-0.5组大菱鲆幼鱼SGR和FE较对照组提高(P>0.05),VSI低于对照组(P<0.05),肥满度(CF)高于对照组(P<0.05);C-0.5组SGR较对照组降低(P<0.05),但FE、VSI和CF与对照组差异不显著(P>0.05);T-1、T-2组大菱鲆幼鱼肝脏、脑和眼中TauT mRNA相对表达量低于对照组(P<0.05),且随着饲料中牛磺酸含量的增加大菱鲆幼鱼肝脏、脑和眼中TauT mRNA相对表达量降低(P<0.05);M-0.5组大菱鲆幼鱼肝脏、脑和眼中TauT mRNA相对表达量高于T-0、T-1、T-2组(P<0.05);C-0.5组大菱鲆幼鱼肝脏、脑和眼中TauT mRNA相对表达量高于T-0、T-1、T-2组(P<0.05),但与M-0.5组相比差异不显著(P>0.05)。综合分析表明,在实验条件下,饲料中牛磺酸含量为0.48%、1.06%时能够提高大菱鲆幼鱼的生长性能;大菱鲆幼鱼体内TauT mRNA表达可能受饲料中牛磺酸、蛋氨酸和半胱氨酸等含硫氨基酸的影响。

A 10-week feeding experiment in indoor flowing-through water system was conducted to evaluate the ef-fects of taurine, methionine and cysteine in diets on growth performance and taurine transporter （TauT） mRNA expres-sion of juvenile turbot （Scophthalmus maximus L.） [initial weight：（7.90±0.07） g]. The basal diet was supplemented with 0, 1%, 2%taurine, 0.5%methionine and 0.5%cysteine （Control T-0, T-1, T-2, M-0.5 and C-0.5, respectively） to formulate five isonitrogenous and isolipidic diets. The results showed that the specific growth rate （SGR） and feed effi-ciency （FE） of T-1 and T-2 group were significantly higher than that of the control group （P〈0.05）, and the visceral in-dexes （VSI） of T-1 and T-2 group was significantly lower than that of the control group （P〈0.05）. Compared with T-0 group, the SGR and FE of M-0.5 group improved （P〉0.05）, and VSI decreased significantly （P〈0.05）, while condition factors （CF） increased significantly （P〈0.05）. Compared with T-0 group, the SGR of C-0.5 group decreased signifi-cantly （P〈0.05）, and no significant differences in FE, VSI and CF were observed （P〉0.05） between the two groups. T-1 and T-2 group had significantly lower TauT mRNA relative expression （P〈0.05） in liver, brain and eye tissues than those in T-0 group, and the TauT mRNA relative expression in liver, brain and eye tissues decreased significantly （P〈0.05） with increasing dietary taurine level. On the contrary, the TauT mRNA relative expression in liver, brain and eye tissues of M-0.5 group was significantly higher （P〈0.05） than those in T-0, T-1 and T-2 groups. C-0.5 group had a significantly higher TauT mRNA relative expression （P〈0.05） in liver, brain and eye than those in T-0, T-1 and T-2 groups, but no significant differences （P〉0.05） were found when compared with M-0.5 group. In conclusion, 0.48%, 1.06%taurine in diets could promote growth performance of juvenile turbot under these experimental conditions. The TauT mRNA expression in juvenile turbot may be affected by dietary sulfur-containing amino acids such as taurine, methionine and cysteine.