半胱胺盐酸盐在大口黑鲈饲料中的应用及耐受性评价

TOLERANCE AND EFFICACY OF CYSTEAMINE HYDROCHLORIDE IN THE DIETS OF LARGEMOUTH BASS (MICROPTERUS SALMOIDES)

实验结合营养学和毒理学的实验方法,对饲料中不同剂量半胱胺盐酸盐预混剂(Cysteamine Hydrochloride,CSH,含量27%)对大口黑鲈(Micropterus salmoides)生长性能、血液生理生化指标、消化酶活性和器官组织学的影响进行了评估,研究其对大口黑鲈生长性能的影响,并对CSH作为大口黑鲈饲料添加剂的安全性进行评价。结果表明:CSH添加量为648 mg/kg组的鱼体特定生长率和摄食率以及肠道胃蛋白酶、胰蛋白酶活性均显著高于对照组(P<0.05),但饲料系数、存活率、肥满度、内脏比和肝指数、血液生理生化指标、淀粉酶活性对照组相比差异不显著(P>0.05),该组大口黑鲈肝脏和肠道显示轻微损伤。添加32400 mg/kg组,各项生长指标、存活率、胃蛋白酶和胰蛋白酶活性均显著小于对照组(P<0.05)。根据大口黑鲈生长、消化酶活性及组织切片结果确定受试物(含CSH27%)对大口黑鲈56d最大未观察到有害作用剂量(NOAEL)为24 mg/kg.w.d,折算CSH对大口黑鲈56dNOAEL为6.5 mg/kg.w.d。

The effects of dietary cysteamine hydrochloride（CSH） on growth performance,hematology and histopathology of liver and intestine of largemouth bass（Micropterus salmoides） were conducted for safety assessment of CSH in fish diet.The CSH was designed at levels of 0,108,324,648 and 32400mg/kg diet respectively.The highest dose group was 100 times higher than optimum.The control diet had inclusion with 38.93% crude protein,9.82% crude fat and 18.86 MJ/kg gross energy.Each diet was fed to triplicate groups of the experimental fish [initial body weight was（14.25±0.1）g] rearing in a re-circulating system for 8 weeks.The experimental fish were fed twice daily and at the start and end of the experiment,the fish were starved for 24h and batch weighed.Results showed that special growth rate,feed intake and the activity of pepsase,trypsinase in intestine of fish fed diet with 648mg/kg CSH level were significantly higher than those of control group.However,feed conversion ratio,survival,hematological indexes and amylase activity in intestine did not show significant difference from those of control and lower CSH inclusion level groups.In the highest concentration（32400mg/kg）,the growth performance,survival and the activity of pepsase,trypsinase of fish were decreased significantly.The frequency of pyknosis in liver and abnormal symptom of intestine in fish fed 648mg/kg diet were observed.Accordingly,the NOAEL of tested additive（including 27% CSH） in the diets of largemouth bass was 24 mg/kg.w.d.The NOAEL of CSH in the diets of largemouth bass was 6.5 mg/kg.w.d.