Effects of Carbon/Nitrogen Ratio on Growth, Intestinal Microbiota and Metabolome of Shrimp (Litopenaeus vannamei)

Abstract

Increasing the C/N ratio of input feed has been reported as a practical approach for improving water quality and enhancing shrimp growth through changing the bacterial community of rearing water. However, little is known about the effects of different C/N ratios of feed input on the intestinal microbiota and metabolome of shrimp. In the present study, the effects of three different C/N ratio levels (CN6, CN10, and CN15) maintained by adding sucrose on the growth, intestinal microbiota and metabolome of Litopenaeus vannamei, and bioflocs formation were investigated after 17 days of feeding. The results indicated that higher C/N ratio (10 and 15), especially CN15, of feed input significantly enhance the length and weight of shrimp individuals accompanied by a significant accumulation of bioflocs, compared to that of CN6. The increase of C/N ratio input decreased the α-diversity of the intestinal microbiota and changed the microbial community structure through increasing the relative abundance of Actinobacteria, Rhodobacteraceae (mainly consist of Roseobacter and Paracoccus groups), Alteromonadaceae, and inhibiting the growth of Cyanobacteria, certain Rhodobacteraceae, Mycoplasmataceae and Vibrio. The change of microbial community caused by increasing C/N ratio input was closely associated with various bioactive metabolites of flavonoids, benzenoids, prenol lipids, and indole derivatives, which are benefit for shrimp growth either as an antimicrobial agent or as a nutrient component. Overall, this study demonstrated that manipulating high C/N ratio of feed input helps to the growth of shrimp through increasing the relative abundance of potential beneficial bacteria and the accumulation of various bioactive metabolites to suppress the growth of detrimental bacteria.

Analysis of microbiota in the stomach and midgut of two penaeid shrimps during probiotic feeding

“…On the other hand, Rhodobacteraceae in the stomach of whiteleg shrimp was decreased. Rhodobacteraceae had been reported as potential probiotics, however, the positive and negative effects of Rhodobacteraceae on the growth of shrimp was suggested by Guo et al (2020) 35 . Because the partial 16S rRNA gene amplicon sequencing cannot accurately distinguish members of Rhodobacteraceae to finer taxonomic levels 36 , the genomic analyses are needed to determine the function of those bacteria on shrimp.…”

Structure, proximate composition, nutrient dynamics and growth characteristics of Penaeus vannamei in indoor biofloc systems with three different salinities and carbon sources

“…Though the biofloc are the conglomerates of heterotrophic bacteria, protozoa and algae, whereas at higher C:N ratios the microbiota mostly dominated by heterotrophic bacteria. In the present experiment, at the maintained C:N ratio of 15:1 biofloc mostly dominated by heterotrophic bacteria (Guo et al, 2020). Though the structure in SEM images of biofloc showed mostly round shaped colonies, the microbial communities in the biofloc treatments showed significant differences in the abundances than that of controls based on the Bray-Curtis overall average dissimilarity index (81%).…”

Healthy microbiome: a key to successful and sustainable shrimp aquaculture

“…Another study reveals the presence of Proteobacteria (most abundant), Bacteroidetes, Cyanobacteria, Actinobacteria, Planctomycetes, and Verrumicrobia in L. stylirostris culture system utilizing BFT (Cardona et al 2016). Guo et al (2020) evaluated the effect of various C/N ratio levels on intestinal microbiome and metabolome of L. vannamei as well as biofloc formation by supplementing sucrose into the culture system. The increment of the C/N ratio reduced the a-diversity of the shrimp gut microbiota and altered the microbial population.…”

“…Guo et al . (2020) evaluated the effect of various C/N ratio levels on intestinal microbiome and metabolome of L. vannamei as well as biofloc formation by supplementing sucrose into the culture system. The increment of the C/N ratio reduced the α‐diversity of the shrimp gut microbiota and altered the microbial population.…”