不同配比复合益生菌对灰海马幼苗存活、生长及免疫的影响

Effects of three probiotics in different proportions on survival,growth and immune response of Hippocampus erectus juveniles

以枯草芽孢杆菌(Bacillus subtilis)、植物乳杆菌(Lactobacillus plantarum)和粪肠球菌(Enterococcus faecalis)为菌源,研究了不同配比复合益生菌对灰海马(Hippocampus erectus)幼苗养殖效果的影响。实验包括3个单菌处理和6个复合菌处理(3种菌1∶2∶3比例的随机组合),共9个加菌处理,另设无菌处理作为对照。用于评估养殖效果的指标包括:养殖水体菌群、幼苗特定存活率和生长率、幼苗肠道免疫指标(免疫球蛋白Ig M、白介素IL-1β、干扰素IFN-α和肿瘤坏死因子TNF-α)和肠道菌群。结果发现:加菌处理组中,其养殖水体均含有大量的目标益生菌,并且养殖水体的弧菌含量均显著低于对照组。幼苗存活率方面,除了D组(芽孢∶乳杆∶粪肠=1∶2∶3)、E组(芽孢∶乳杆∶粪肠=1∶3∶2)和F组(芽孢∶乳杆∶粪肠=2∶1∶3)的存活率显著低于对照组外,其他组存活率均显著高于对照组,其中G组(芽孢∶乳杆∶粪肠=2∶3∶1)和I组(芽孢∶乳杆∶粪肠=3∶2∶1)的存活率最高,均超过了65%。特定生长率除了B组(植物乳杆菌单菌处理)与E组外,其余各组之间均无显著性差异(P>0.05)。肠道免疫指标和菌群方面,存活率高的组别Ig M含量就高(通常指示免疫力水平),肠道内亦含丰富的枯草芽孢杆菌、蜡样芽孢杆菌(B.cereus)、植物乳杆菌和约氏乳杆菌(L.johnsonii);而存活率低的组别则Ig M含量低,而IL-1β、IFN-α和TNF-α含量高(往往是炎症的征兆),另外肠道内菌群比例失衡,益生菌丰度低。结果表明:复合益生菌的使用需要有一个特定的配比,配比合适益生效果优于单菌,配比失衡则不如单菌,甚至不及无菌,枯草芽孢杆菌、植物乳杆菌和粪肠球菌按2∶3∶1或3∶2∶1配比混合使用效果最佳。

Three probiotics,Bacillus subtilis,Lactobacillus plantarum and Enterococcus faecalis,were employed to investigate the effects of probiotics in different proportions on survival,growth and immune response of lined seahorse Hippocampus erectus juveniles.The designed treatments included a random combination of three probiotics in a proportion of 1∶2∶3(six treatments in total),together with another three treatments of single probiotic.No probiotic was as the control.The parameters included bacterial flora in aquaculture water,specific growth rate and survival rate of the juveniles,immune parameters(Ig M,IL-1β,IFN-αand TNF-α)and bacterial flora in the intestinal tract.Results showed that there were a large number of target probiotic bacteria in aquaculture water in the probiotic treatments.In addition,Vibrio number in the probiotic treatments was significantly lower than that in the control.Except for treatment D(B.subtilis∶L.plantarum∶E.faecalis=1∶2∶3),treatment E(B.subtilis∶L.plantarum∶E.faecalis=1∶3∶2)and treatment F(B.subtilis∶L.plantarum∶E.faecalis=2∶1∶3),the survival rates of other treatments were significantly higher than that of the control.Treatment G(B.subtilis∶L.plantarum∶E.faecalis=2∶3∶1)and treatment I(B.subtilis∶L.plantarum∶E.faecalis=3∶2∶1)had the highest survival rate(>65%).For the intestinal immune parameters and microbial flora,groups with higher survival rate had higher Ig M content,indicating higher immunity level,and had abundant intestinal microbial flora,such as B.subtilis,B.cereus,L.plantarum and L.johnsonii.Groups with lower survival rate had higher IL-1β,IFN-αand TNF-α,which are often signs of inflammation,and had an unbalanced intestinal microbial flora with low probiotic abundance.It is concluded that the matching use of compound probiotics requires an appropriate ratio.If the matching ratio is appropriate,the beneficial effect of compound probiotics is better than a single one,but if the ratio is unbalanced,the effect is even worse than that of non-probiotic treatment.In the present study,B.subtilis,L.plantarum and E.faecalis matched at the ratio of 2∶3∶1 or 3∶2∶1 has the optimal effect.