草鱼肠道拮抗性芽孢杆菌的冻干保护剂优化研究

Optimization of Freeze-dried Protective Agent for Pathogenic Antagonistic Bacillusin Grass Carp Gut

自草鱼肠道内提取的病原拮抗性芽孢杆菌能有效提高草鱼免疫能力,从而促进草鱼的健康生长。为提高本试验病原拮抗性芽孢杆菌保存活力,采用L_9(3~4)正交试验法,以病原拮抗性芽孢杆菌冻干保护剂在冷冻干燥后菌体成活率为考察指标,对麦芽糊精、甘氨酸和海藻糖3个变量因素进行考察。结果表明,当以冻干后菌体成活率为考察指标时,各因素对菌体冻干粉的保存活性作用影响为麦芽糊精>甘氨酸>海藻糖,3种赋形剂对菌体保护最佳配方为A_1B_1C_3,即2%麦芽糊精,0.5%甘氨酸,6%海藻糖。通过该试验方案得到了病原拮抗性芽孢杆菌冻干保护剂的最优配方。

A spore-producing bacterial strain enhancing the immunity and promoting growth was isolated from intestinal tract of grass carp Ctenopharyngodon idellus. The optimized concentrations of maltodex- trin, glycine and trehalose were investigated by L9 （34） orthogonal test via the survival rate of freeze-dried Antagonistic Bacillus as on index. The results showed that the decreasing order of effects of mahodextrin, glycine and trehalose was expressed as： maltodextrin 〉 glycine 〉 trehalose. And the optimized formula- tion of freeze-dried protective agent for pathogenic antagonistic Bacillus was A1 B1 C3, that is, 2% maho- dextrin,0.5 % glycine, and 6 % trehalose. The findings indicate that the best protective agent can be used in grass carp.