Effects of feed binder on water quality,growth and intestinal microbiota in recirculating aquaculture system of Apostichopus japonicas
Water quality is crucial for Apostichopus japonicas farming and may affect its growth and physiological functions.The accumulation of residual bait and feces usually leads to turbidity and high concentration of solid particles in aquaculture water,resulting in nutrient accumulation and frequent disease outbreaks.This poses a huge threat to the A.japonicas farming industry.Therefore,this study aims to explore the effects of different feed binders on water quality,growth and intestinal microbiota of A.japonicus in recirculating aquaculture system(RAS).Five groups were set up,including no binder group and four groups with added 5％sweet potato starch,xanthan gum,guar gum and carrageenan respectively.A.japonicus weighing 20.0±5.0 g were used for researching.Each group had three replicates and the experiment last for 42 days.Kruskal-Wallis rank sum test was used to analyze the difference of intestinal microbiota between groups.Redundancy analysis(RDA)and Canonical correlation analysis(CCA)were used to investigate the relationship between water quality and intestinal microbiota of A.japonicus.The results showed that adding binders improved water quality well,with the guar gum group would give a better result.The concentrations of ammonia nitrogen(NH4-N),nitrate nitrogen(NO3--N)and total nitrogen(TN)in guar gum group were the lowest at the end of the experiment,and fluctuated less during the experiment.The specific growth rate(RSGR)and feed conversion rate of A.japonicus in sweet potato starch and guar gum groups were significantly higher than that in other groups(P＜0.05)and the skin exfoliation rate(RSER)were increased in both groups.The dominant intestinal microflora of cultivation were Proteobacteria.Vibrionaceae and Rhodobacteraceae were the dominant family.And there was significantly different in intestinal microbiota among the groups.The sweet potato starch group had the highest intestinal microflora richness and diversity,while the lowest in the xanthan gum group.The results of significance difference test between groups showed that the feed with added sweet potato starch increased the abundance of beneficial bacteria of A.japonicus,such as Flavobacteriaceae.There was significant correlation between water quality and intestinal microbiota of A.japonicus(P＜0.05).At the phylum level,NH4+-N,NO2--N,NO3--N were negatively correlated with Firmicutes,Actinobacteriota and Bacteroidota.But positively correlated with Verrucomicrobia and Proteobacteria.At the family level,NH4+-N,NO2--N,NO3--N were positively correlated with Vibrionaceae and Shewanellaceae,while negatively correlated with Flavobacteriaceae and Enterobacteriaceae.Considering the water quality,growth and intestinal microflora of A.japonicus,sweet potato starch and guar gum as feed binder were more conducive to healthy culture of A.japonicus and maintenance the water treatment in RAS.
万方数据
维普
