本试验旨在探讨饲料中牛磺酸含量对斜带石斑鱼生长性能、体成分及组织游离氨基酸含量的影响。以酪蛋白和明胶为蛋白质源配制低牛磺酸含量的基础饲料,在基础饲料中分别添加0(对照)、0.4%、0.8%、1.2%、1.6%的牛磺酸,配制成5种试验饲料。将300尾平均体重为(19.14±0.06) g斜带石斑鱼幼鱼随机分为5组(每组3个重复,每个重复20尾),每组投喂1种试验饲料,饲养周期为56 d。结果表明：与对照组相比,各牛磺酸添加组试验鱼的增重率、摄食率和饲料效率均显著增加(P<0.05),内脏指数显著降低(P<0.05),肝脏指数、肥满度无显著变化( P>0.05)。与对照组相比,各牛磺酸添加组试验鱼全鱼粗蛋白质含量显著升高( P<0.05),全鱼粗脂肪含量显著降低(P<0.05),全鱼水分和粗灰分含量则无显著变化(P>0.05)。各牛磺酸添加组试验鱼肝脏和肌肉中总非必需氨基酸、总氨基酸、游离丝氨酸含量以及肝脏游离蛋氨酸含量均显著低于对照组( P<0.05)。试验鱼血清、肝脏、肌肉和全鱼中牛磺酸含量随饲料中牛磺酸含量的增加而呈上升趋势,且与饲料中牛磺酸含量存在显著正相关关系( r>0.907,P<0.05)。随饲料中牛磺酸含量的增加,肝脏牛磺酸保留率呈上升趋势,而肌肉中牛磺酸保留率则呈先上升后下降的趋势；此外,各组试验鱼肌肉牛磺酸保留率均高于肝脏。由此得出,饲料中一定含量的牛磺酸能促进斜带石斑鱼生长和摄食,降低全鱼脂肪沉积,增加全鱼蛋白质沉积,降低组织中游离氨基酸含量。以增重率为指标,通过回归分析得出斜带石斑鱼饲料中牛磺酸的适宜含量为1.04%。%This experiment was conducted to study the effects of dietary taurine content on growth perform-ance, body composition and tissue free amino acid contents of grouper ( Epinephelus coioides) . Casein and ge-latin were used as protein sources, a low taurine content basal diet was formulated. The taurine was supplemen-ted to the basal diet at 0 ( control) , 0.4%, 0.8%, 1.2% and 1.6%, respectively, to formulate 5 experimental diets. Three hundred juvenile groupers with the average body weight of (19.14±0.06) g were randomly divid-ed into 5 groups with 3 replicates per group and 20 fish per replicate. Five groups of fish were allocated one of five experimental diets. The feeding trial lasted for 56 d. The results showed as follows:compared with control group, the weight gain rate, feed intake rate and feed efficiency were significantly increased and viscerasomatic index was significantly decreased in taurine supplementation groups (P<0.05), but no significant differences were found in hepatosomatic index and condition factor among all groups (P>0.05). Compared with control group, the whole-body crude protein content was significantly increased ( P<0.05) and whole-body crude lipid content was significantly decreased in taurine supplementation groups ( P<0.05) , but no significant differences were found in whole-body moisture and ash contents among all groups ( P>0.05) . The contents of total non-es-sential amino acids, total amino acids, free serine in liver and muscle, and free methionine content in liver in taurine supplementation groups were significantly lower than those in control group ( P<0.05) . Taurine content in serum, liver, muscle and whole-body of grouper showed an increasing tendency with the dietary taurine con-tent increasing, and there were significant positive correlations between them and dietary taurine content ( r>0.907, P<0.05) . With the dietary taurine content increasing, the taurine retention in liver was increased and that in muscle was firstly incresed and then decreased; moreover, the taurine retention in muscle was higher than that in liver in all groups. In conclusion, a certain content of taurine in diet can improve the growth and feeding, decrease whole-body lipid deposition, increase whole-body protein deposition, and decrease tissue free amino acid contents of grouper. Regression analysis based on weight gain rate indicates that the optimal di-etary taurine content of grouper is 1.04%.
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