饲料添加牛至精油对异育银鲫生长、消化酶活性、肠道组织结构及血液生化指标的影响

Effects of dietary oregano essential oil on growth,digestive enzyme activity,intestinal tissue structure and blood biochemical indexes in Carassius auratus gibelio

为研究牛至精油对异育银鲫(Carassius auratus gibelio)生长性能、消化酶活性、肠道组织结构和血液生化指标方面的影响,实验选取平均初始体质量为(37.18±0.26)g的健康异育银鲫630尾,设置0(空白对照)、25、50、100、200、400和800 mg/kg 7个牛至精油添加剂量组,进行池塘网箱养殖8周后采样检测分析。结果显示:添加400和800 mg/kg牛至精油组的增重率、肥满度和特定生长率显著高于空白对照组,且饵料系数显著降低;添加800 mg/kg牛至精油组的增重率、肥满度和特定生长率显著高于25和50 mg/kg牛至精油组。与空白对照组相比,添加200和400 mg/kg牛至精油组的鱼体胰蛋白酶、脂肪酶和α-淀粉酶活性显著升高。其中,α-淀粉酶与脂肪酶活性呈先升高再降低趋势,且均在牛至精油水平为200 mg/kg时达到最大值,并显著高于25和800 mg/kg组,与100和400 mg/kg组之间无显著差异。添加200和400 mg/kg牛至精油组的鱼体后肠的肠壁厚度、肠绒毛高度、肠绒毛宽度和杯状细胞数量均显著高于空白对照组,而添加800 mg/kg牛至精油组鱼体后肠的肠绒毛高度和绒毛宽度显著高于50和200 mg/kg组,与400 mg/kg组之间无显著差异。各实验组的总胆固醇(TC)、甘油三酯(TG)和总胆红素(TBIL)与空白对照组相比均无显著性差异;添加50、100、200、400和800 mg/kg牛至精油组血液中谷草转氨酶(AST)活性显著低于空白对照组,而各实验组之间差异不显著。综上,饲料添加牛至精油能有效提高异育银鲫的生长性能,促进其肠道消化酶活性和改善肠道组织形态结构。综合异育银鲫生长性能、肠道组织结构及消化酶活性和血清生化指标,建议饲料牛至精油添加量为100~400 mg/kg。

The current study was designed to evaluate the effects of dietary oregano essential oil on the indices of growth and digestive enzyme activity,serum biochemistry,and histomorphological criteria of intestines of Carassius auratus gibelio.A total of 630 healthy fish(37.18±0.26 g)were randomly divided into seven treatments and fed on different levels of oregano essential oil at 0,25,50,100,200,400,and 800 mg/kg diet for two months.The results showed that the dietary oregano essential oil significantly improved the growth parameters(weight gain rate,condition factor,and specific growth rate)in the groups fed with essential oregano oil at 400 and 800 mg/kg.Meanwhile,the feed conversion ratio was significantly decreased concerning the control group.The weight gain rate,condition factor,and specific growth rate of the 800 mg/kg group were significantly higher than that in the 25 and 50 mg/kg groups.Besides,significant enhancement was noticed in the levels of intestinal digestive enzymes(trypsin,lipase,andα-amylase)in the 200 and 400 mg/kg groups.The levels of lipase andα-amylase increased first and then decreased and reached the maximum when the level of oregano essential oil was 200 mg/kg,which was significantly higher than in the 25 and 800 mg/kg groups.All the intestinal morphometric measurements(intestinal wall,villus height,villi width,and the number of goblet cells)revealed a significant improvement in 200 and 400 mg/kg groups in comparison with the control group.The villus height and villus width of the 800 mg/kg group were significantly higher than that in the 50 and 200 mg/kg groups.The levels of total cholesterol(TC),triglyceride(TG),and total bilirubin(TBIL)were not significantly altered by oregano essential oil supplementation.Moreover,the level of aspartate aminotransferase(AST)in 50,100,200,400,and 800 mg/kg groups were significantly decreased compared to the control group,while no significant difference has been found between each two treatments.In conclusion,this study demonstrated that dietary of essential oregano oil effectively improved growth performance,digestive enzyme activity,and intestinal morphology of C.auratus gibelio.The growth performance,intestinal morphology,digestive enzymes,and serum biochemical indexes of C.auratus gibelio are suggested to add 100~400 mg/kg of essential oregano oil to feed.