大菱鲆幼鱼对饲料中泛酸最适需求量的研究

Study on the Optimum Dietary Pantothenic Requirement of Juvenile Turbot (Scophthalmus maximus L.)

中文关键词: 大菱鲆  泛酸  生长性能  需求

英文关键词: Juvenile turbot  Pantothenic acid  Growth performance  Requirement

中文摘要:

      为研究大菱鲆(Scophthalmus maximus)幼鱼对泛酸的最适需求量，在基础配方中添加不同梯度的泛酸钙，制成6组泛酸含量分别为6.24、10.64、15.02、23.81、41.40和76.57 mg/kg等氮等能实验饲料，投喂初始体重为(24.73±0.10) g的大菱鲆幼鱼80 d。结果显示：1)泛酸对幼鱼成活率(SR)无显著影响(P>0.05)，10.64~76.57 mg/kg饲料组增重率(WGR)和特定生长率(SGR)显著提高(P< 0.05)；泛酸含量超过23.81 mg/kg时，肝体比(HSI)显著降低(P<0.05)；2)随着饲料中泛酸含量的提高，全鱼粗蛋白、粗脂肪和肌肉粗蛋白均呈先升后降趋势，肝脏脂肪含量显著下降(P<0.05)；3)肠道消化酶、Na+, K+-ATPase和肝脏胆碱酯酶(ChE)活力随泛酸添加量的增加呈先上升后下降趋势，10.64~76.57 mg/kg饲料组肠道肌酸激酶(CK)活力显著提高(P<0.05)；4)血清、肝脏中过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活力均呈先升后降趋势；6.24 mg/kg饲料组血清丙二醛(MDA)含量显著高于其他5组(P<0.05)；5)随泛酸含量的增加，肝脏脂肪合成酶(FAS)基因表达量先升后降，脂蛋白酯酶(LPL)基因表达量显著上升(P<0.05)。研究表明，饲料中添加适宜的泛酸能显著增强大菱鲆幼鱼肠道消化、吸收能力和机体抗氧化能力，并可提高脂肪代谢相关基因的表达水平，从而提高其生长性能。以增重率为判据，经折线模型拟合得出，初体重为24.73 g的大菱鲆幼鱼对泛酸的需求量为16.08 mg/kg饲料。

英文摘要:

      An 80-day feeding trial was conducted to investigate the pantothenic acid dietary requirements of juvenile turbot. Six isoenergetic and isonitrogenous diets were formulated using fish meal and casein as a protein source. The basal diet was supplemented with calcium D-pantothenic acid at 6.24, 10.64, 15.02, 23.81, 41.40, or 76.57 mg/kg and fed to juveniles weighing (24.73±0.10) g. The results were as follows: 1) No significant differences in juvenile turbot survival rate (SR) were found between the dietary treatments (P>0.05) and the weight growth rate (WGR) and specific growth rate (SGR) increased as pantothenic acid levels increased from 10.64 to 76.57 mg/kg (P<0.05). For dietary pantothenic acid content greater than 23.81 mg/kg, the hepatosomatic index decreased significantly (P<0.05). 2) The crude protein and lipid levels of the whole body and crude protein levels of the muscle initially increased and then decreased with increasing dietary pantothenic acid levels, whereas the crude lipid content of the liver decreased (P<0.05). 3) The activities of the intestinal digestive enzymes Na+, K+-ATPase and hepatic cholinesterase (ChE) initially increased and then decreased with increasing dietary pantothenic acid levels, whereas intestinal creatine kinase (CK) activity increased significantly from 10.64 to 76.57 mg/kg (P<0.05). 4) Hepatic and serum catalase (CAT) and superoxide dismutase (SOD) activities were significantly lower in the control group than in the groups with calcium pantothenic acid-enriched diets (P<0.05). Turbot fed a 6.24 mg/kg pantothenic acid diet had a higher serum malondialdehyde content than those fed other diets (P<0.05). 5) Fatty acid synthetase (FAS) expression increased and then decreased with increasing levels of pantothenic acid. Lipoprotein lipase (LPL) expression was significantly up-regulated in the liver with increasing levels of pantothenic acid (P<0.05). In conclusion, appropriate levels of dietary pantothenic acid significantly improved intestinal digestion and absorption capacity, thus, improving nonspecific immunity and the expression of fat-related genes, and consequently, the growth and body composition of juvenile turbot. Based on broken-line regression analysis of WGR, the optimum dietary pantothenic acid requirement of juvenile turbot with a body weight of 24.73 g was 16.08 mg/kg.