Enhanced analysis of growth, histology, and metabolomics profiles in Penaeus vannamei fed distillers dried grains with solubles supplemented with butyric acid

This study thoroughly analyzes the growth, histology, and metabolomics profiles of Penaeus vannamei shrimp when fed a diet high in distillers dried grains with solubles (DDGS) supplemented with butyric acid (BA). The limited research on BA supplementation in high levels of DDGS makes this study particularly valuable, as its antimicrobial properties and improved nutrient absorption are crucial for promoting shrimp health. A total of 720 shrimp were divided into six groups, each receiving varying levels of BA supplementation: 0%, 0.5%, 1%, 1.5%, 2%, and 2.5%. The experiment lasted 56 days, with three replicates for each group. The results showed significant increases in final weight (FW), weight gain rate (WGR), and specific growth rate (SGR) with higher levels of dietary BA (P < 0.05). Additionally, dietary BA led to a notable decrease in feed conversion ratio (FCR), with the most significant impact observed in the 1.5% BA group (P < 0.05). Histological analysis of the hepatopancreas revealed that shrimp-fed diets containing 1.5% and 2% BA displayed significantly higher B-cell numbers with a well-defined structure than the other groups. Metabolomics analysis showed distinct quadrants in the PCA score plots for the control and BA groups, indicating a clear separation in their metabolic profiles. Integration analysis of differential metabolites and genes further revealed the upregulation of functions related to ABC transporters, amino acid biosynthesis, and metabolism in shrimp supplemented with BA. Our findings suggest that the optimal BA requirement for supplementation in the DDGS diet for P. vannamei is estimated to be 1.6%. This information will be valuable for farmers during feed formulation and aquaculture growth in general.