Influence of dietary inulin on growth and intestinal ecology in Pacific white shrimp (Litopenaeus vannamei)

Abstract

This study investigates the influence of dietary inulin on the growth and health of juvenile shrimp Litopenaeus vannamei over an 8-week trial, focusing on growth, health, and metabolic impacts because of diet variation. A total of 240 shrimp with an initial mean weight of 0.26 ± 0.01 g were distributed across 12 recirculating tanks and assigned diets with varying inulin concentrations: 0% (Control), 0.5% (T1), 1.0% (T2) and 1.5% (T3). Results indicated that the 1.0% inulin diet resulted in the highest specific growth rate, weight gain, and survival rate. An increase in antioxidative and immune enzyme activities suggested improved health conditions at optimal inulin levels, evidenced by the reduction of malondialdehyde content and potentiation of enzymes like superoxide dismutase and lysozyme. Microbiome analysis via 16S rRNA sequencing showed a significant shift in gut bacterial populations, with an increase in beneficial bacteria such as Xanthomarina and a reduction in pathogenic Vibrio and Flavobacteria in inulin-supplemented groups. Higher dietary inulin increased gut microflora diversity significantly in the T2 group. Metabolomic analysis showed distinct pathway enrichment and differential metabolite regulation, linking inulin intake to significant alterations in lipid metabolism, including pathways like bile secretion, arachidonic acid metabolism, steroid hormone biosynthesis, and ABC transporters. Furthermore, correlation and KEGG enrichment analyses revealed intricate interactions within the shrimp metabolic network, pointing to compensatory and regulatory mechanisms in response to inulin supplementation. In conclusion, dietary inulin substantially improves the health and growth of L. vannamei, likely by modulating gut microbiota and metabolic pathways. This study highlights the potential of inulin as a significant dietary supplement for enhancing shrimp aquaculture efficacy.