中草药复合微生态制剂对吉富罗非鱼(Oreochromis niloticus)生长、肠道菌群及抗病力的影响

通过在饲料中分别添加2×107 CFU/g的芽孢杆菌制剂、中草药芽孢杆菌制剂、复合微生态制剂和中草药复合微生态制剂，研究4种微生态制剂对吉富罗非鱼(Oreochromis niloticus)生长、肠道菌群及抗病力等的影响。结果显示：(1)饲料中添加4种微生态制剂均可显著提高罗非鱼的增重率(P<0.05)，对成活率和饲料利用率也有一定程度的提高(P>0.05)，而中草药复合微生态制剂对罗非鱼促进生长效果最佳。(2)饲料中添加4种微生态制剂可以显著提高罗非鱼肠道中的细菌总数、芽孢杆菌、乳酸杆菌和双歧杆菌数量(P<0.05)，大肠杆菌数量显著低于对照组(P<0.05)，说明饲料中添加一定量的4种微生态制均可改善罗非鱼的肠道菌群结构，以中草药复合微生态制剂的改善效果最佳。(3)经人工感染无乳链球菌后，罗非鱼对照组全部死亡，4个实验组只有部分死亡。鉴定发现，吉富罗非鱼的死亡均由感染无乳链球菌所致，试验组罗非鱼的免疫保护率分别为51.42%(B组)、58.62%(C组)、58.62%(D组)和68.93%(E组)，以中草药复合微生态制剂组的免疫保护率最高。综上所述，在饲料中添加一定比例的中草药复合微生态制剂可以提高吉富罗非鱼生长指标、改善其肠道菌群结构和增加抗病力。

Effects of a Compound Probiotics Combined with Chinese Herbal Medicine on Growth Performance, Intestinal Flora and Resistance to Diseases of GIFT Strain of Nile Tilapia (Oreochromis niloticus)

Here we studied the effects of four kinds of probiotics on the growth performance, intestinal flora, and resistance to diseases of GIFT strain of Nile tilapia (Oreochromis niloticus). Bacillus subtilis, Chinese herbal medicine compound Bacillus subtilis, compound probiotics, and Chinese herbal medicine compound probiotics were added into feed at the concentration of 2×107 CFU/g to form four treatment groups. The results were shown below: (1) All four probiotics obviously improved the weight gain rate of Nile tilapia (P<0.05). Probiotics also insignificantly promoted the survival rate and feed efficiency (P>0.05), and Chinese herbal medicine compound probiotics exhibited the best effect. (2) All four types of probiotics caused an increase in the total amounts of bacteria, bifidobacterium, lactobacillus, and bacillus in the guts of Nile tilapia (P<0.05), whereas the number of Escherichia coli was significantly reduced compared to the control group (P<0.05). These results indicated that all four probiotics in the feed could improve the structure of intestinal flora in Nile tilapia, and among them Chinese herbal medicine compound probiotics was the most effective. (3) After the Streptococcus agalactiae infection administered with artificial intraperitoneal injection, all the Nile tilapia in the control group died, but the infection was only fatal to some individuals in the treatment groups. Further tests confirmed streptococcus infection as the reason of death of Nile tilapia. The immune protection rates of the four probiotics were 51.42% (Group B), 58.62% (Group C), 58.62% (Group D) and 68.93% (Group E), again Chinese herbal medicine compound probiotics (Group E) showed the highest efficiency. In conclusion, adding a proper portion of Chinese herbal medicine compound probiotics into feed could effectively improve the growth index, the structure of intestinal flora, and the disease resistance of Nile tilapia.