刺参饲料发酵条件的优化及其对生长性能、肠道微生物多样性和水环境的影响

Optimization of Dietary Fermentation Conditions of Apostichopus japonicus and Its Effects on Growth Performance,Gutmicrobiota and Water Environment

【目的】优化刺参(Apostichopus japonicus)饲料发酵条件并验证其对生长性能、肠道微生物多样性和水环境的改善,为刺参绿色高效养殖技术的开发提供理论支撑。【方法】选择酿酒酵母菌(Saccharomyces cerevisiae)、枯草芽孢杆菌(Bacillus subtilis)和植物乳杆菌(Lactobacillus plantarum)作为发酵菌种进行发酵时间和菌种比例的筛选,确定刺参商品饲料适宜发酵条件;使用发酵饲料分别以10%、20%、30%及40%质量分数比例替代普通饲料,进行40 d周期养殖,取样分析生长指标、体常规成分、肠道酶活性、菌群多样性和水环境等指标。【结果】35℃下3菌种混合发酵3 d时酸溶蛋白质量分数最高,且显著高于大部分实验组(P<0.05),即为发酵最优组;随着发酵饲料替代量升高,刺参增重率和特定生长率呈先升高后降低趋势,质量分数20%替代量时显著高于其他实验组(P<0.05),其他实验组与对照组无显著差异(P>0.05);发酵饲料替代后淀粉酶等消化酶含量有所增加,20%替代量时显著高于其他实验组(P<0.05),其他实验组与对照组无显著差异(P>0.05);肠道绒毛高度和肠道微生物多样性均在发酵饲料替代后有所增加,并在20%替代量时显著最高(P<0.05),同时有效提高厚壁菌门中动性球菌等有益菌的定植;发酵饲料替代后可有效降低养殖水体总氮、总磷质量浓度,20%替代量时达到最优。【结论】本实验所使用商品饲料的最适发酵条件为枯草芽孢杆菌、酿酒酵母菌和植物乳杆菌的质量之比为1∶1∶1,35℃下共同发酵3 d,添加质量分数20%发酵饲料可有效优化肠道结构,提高消化率进而促进刺参生长。

【Objective】We optimized the fermentation conditions of Apostichopus japonicus diets,explored its effects on growth performance,intestinal microbial diversity and water environment to achieve the purpose of green and efficient culture of A.japonicus.【Method】Saccharomyces cerevisiae,Bacillus subtilis and Lactobacillus plantarum were used as the fermentation strains,the fermentation time and the proportion,and the suitable fermentation conditions of diets of A.japonicus were determined.10%,20%,30%and 40%mass fraction fermented diets were used to replace the ordinary for 40 days.The growth performance,body composition,intestinal enzyme activity,gut microbiota and water environment were sampled and analyzed.【Result】Diets fermented by the three strains together at 35℃for 3 days,contained the highest content of acid soluble protein(ASP),which was significantly higher than most groups(P<0.05).With the increase of the replacement amount of fermented diets,the weight gain rate and specific growth rate of A.japonicus increased first and then decreased,with the 20%fermented diets replacement group performing best(P<0.05),and there was no significant difference between other experimental groups and control group(P>0.05).The contents of amylase increased after the fermented diets replacement,and were the highestin the 20%replacement group(P<0.05),there was no significant difference between the other groups and the control group(P>0.05).The villus height and intestinal microbial diversity were both increased after fermented diets replacement,and were thehighest in the 20%replacement group(P<0.05),which effectively improved the colonization of beneficial bacteria such as Planoccoccus in Firmicutes.【Conclusion】The contents of total nitrogen and phosphorus in the water could be effectively reduced by fermented diets replacement,and the optimal replacement amount was 20%.The fermentation effect was the best when the ratio of S.cerevisiae to B.subtilis to L.plantarum was 1∶1∶1 for 3 d.Adding 20%fermented diets can effectively optimize the intestinal structure,improve the digestibility to promote the growth of A.japonicus.