苏云金芽孢杆菌对黄河鲤血液免疫效果研究

Effects of Dietary Bacterium Bacillus thuringiensis on Immune Response of Common Carp Cyprinus carpio in Yellow River

研究了苏云金芽孢杆菌对黄河鲤血液免疫应答的影响。将苏云金芽孢杆菌按1．0×10^11、3．0×10^11、5．0×10^11 cfu／kg3个浓度添加在鱼用全价颗粒饲料中，投喂经嗜水气单胞菌疫苗免疫组（‰～As）和未免疫组（B0～B3）黄河鲤。分别于0、15、30、40d时检测各组黄河鲤白细胞吞噬活性、血清溶菌酶活性以及血清凝集抗体效价，并进行攻毒试验。结果表明：添加苏云金芽孢杆菌可使黄河鲤血液中自细胞吞噬活性和血清溶菌酶活性显著提高。添加组与对照组差异显著（P〈0．05），添加浓度越高，血液白细胞活性和溶菌酶活性越强。免疫组与未免疫组白细胞吞噬活性差异不显著（P〉0．05），而溶菌酶活性差异显著（P〈0．05）。在停止投喂后10d，白细胞活性、血清溶菌酶活性逐渐下降，但差异不显著（P〉0．05）。添加苏云金芽孢杆菌还可提高黄河鲤的凝集抗体效价及攻毒后的存活率。其中，当菌株添加浓度为5．0×10^11 cfu／kg时．受免疫的黄河鲤免疫保护率最高。即投喂苏云金芽孢杆菌对黄河鲤血液免疫应答有明显促进作用。

The common carp Cyprinus carpio immunized with Aacillus hydrophila （groups A0-A3） and un-immunized （groups B0-B3） were fed the diets containi 1.0 × 10^11 , 3.0 × 10^11 , and 5.0 × 10^11 cfu/kg to investigate sponse of the common carp in Yellow River. The ph and agglutinating antibody titer were determined 0, ng th agocyti 15, 30 bacterium Bacillus thuringiensis at a rate of e effect of the bacterium on the immune reactivities of leucocytes, lysozyme activities, and 40 days after the feeding trial. The resuits showed that the fish fed the diets containing different levels of Bacillus thuringiensis had significant ly enhanced phagocytic activities of leukocytes, and lysozyme activities（P 〈 0.05）, increasing with the increment in the levels of the bacterium. There were no significant differences in phagocytic activities of leukocytes for the immunized and un-immunized fish （P〉0.05）, but significant differences in the lysozyme activities（P〈0.05）. The significant differences in the phagocytic activities of leucocytes and lysozyme activities were not observed days after the fish stopped feeding the diets（P〈0.05）. The different concentrations of Bacillus thuringiensis improved the agglutinating antibody titer and the survival of the fish after the fish challenged with live Aeromonas hydrophila. The immunized fish had the maximal relatlve cfu/ pe kg rcent survival （RPS） when fed the diets containing the Bacillus thuringiensis at a rate of 5.0× 10^11 feed.