裂壶藻对津新鲤(Cyprinus carpio var. Jian)生长、血液非特异性免疫指标及抗病力的影响

Effects of Dietary Schizochytrium on the Growth Performance, Serum Nonspecific Immunity Indices, and Disease Resistance of Cyprinus carpio var. Jian

中文关键词: 裂壶藻  津新鲤  生长  非特异性免疫指标  抗病力

英文关键词: Schizochytrium  Cyprinus carpio var. Jian  Growth  Nonspecific immunity indices  Disease resistance

中文摘要:

      选用初始体重为(26.77±1.56) g的津新鲤(Cyprinus carpio var. Jian) 540尾，随机分为6组，每组3个重复，分别投喂含0、0.40%、0.80%、1.20%、1.60%和2.00%裂壶藻的等氮等能饲料，饲养56 d，探讨饲料中不同水平的裂壶藻对津新鲤生长、血液非特异性免疫指标及抗病力的影响。结果显示，在0.80%裂壶藻水平组中，增重率和特定生长率均显著提高(P<0.05)，肥满度则在1.20%水平组中达到最大值(P<0.05)，各组间成活率差异不显著(P>0.05)。不同水平的裂壶藻均可以显著提高津新鲤的抗氧化能力，其中过氧化氢酶、总超氧化物歧化酶和谷胱甘肽的含量均呈先上升后下降的趋势，且分别在1.20%、0.80%和1.20%组中达到最高(P<0.05)；而丙二醛含量呈先下降后上升的趋势，在0.80%组中达最低(P<0.05)。不同水平的裂壶藻均可以显著提高津新鲤的非特异性免疫力，溶菌酶呈先上升后下降的趋势，其中1.20%组活性最高(P<0.05)。一氧化氮含量随裂壶藻水平增加而增加，各添加组含量均显著高于对照组(P<0.05)。谷草转氨酶/谷丙转氨酶在0.80%组中达到最小值(P<0.05)。随着裂壶藻水平的增加，津新鲤血细胞呼吸爆发活性和免疫保护率得到显著提高，感染嗜水气单胞菌后的累计死亡率则显著降低(P<0.05)，其中，以0.80%组最佳。综合生长、血液非特异性免疫指标和抗病力来分析，饲料中裂壶藻的适宜添加水平为0.80%–1.20%。

英文摘要:

      Five hundred and forty Cyprinus carpio var. Jian with initial body weight of (26.77±1.56) g were randomly divided into 6 groups, and every group had three replicates each of which had 30 fish. Six diets were formulated with Schizochytrium at the concentrations of 0, 0.40%, 0.80%, 1.20%, 1.60% and 2.00%. An 8-week feeding trial was conducted to determine the effects of diary Schizochytrium on growth performance, serum nonspecific immunity indices, and disease resistance of C. carpio Jian. The results showed that weight gain rate and specific growth rate significantly increased in the 0.80% group (P<0.05). The highest condition factor was observed in the 1.20% group (P<0.05). The survival rate showed no significant difference between the six groups (P>0.05). The antioxidant and nonspecific immune activities were apparently altered by Schizochytrium (P<0.05). As the concentration of Schizochytrium increased, the contents of catalase, total superoxide dismutase, and glutathione were first elevated and then reduced, and the maximum of each was observed in the 1.20%, 0.80%, and 1.20% groups respectively (P<0.05). The malondialdehyde content dropped first and then increased with the lowest value observed in the 0.8% group. The nonspecific immune capacity in the 0.80% group was significantly higher than in other groups (P<0.05). The activity of lysozyme was raised and then reduced along with the increase in the Schizochytrium level, and the maximum was observed in the 1.20% group (P<0.05). The nitric oxide content rose along with the rise of Schizochytrium level, and was significantly higher than the control group (P<0.05). The Aspartate aminotransferase/aspartate aminotransferase (GOT/GPT) ratio reached the minimum in the 0.80% group. Also in the 0.80% group, the respiratory burst activity of blood cells was elevated significantly and the accumulated mortality rate was the lowest (P<0.0.5). In conclusion, we recommended that the optimal Schizochytrium level for C. carpio Jian should be 0.80%–1.20%.