Stocking density is a key management factor in intensive shrimp culture because it affects shrimp growth, system loading, and the structure of host-associated microbial communities. In this study, juvenile black tiger shrimp ( Penaeus monodon ) were cultured for 40 days at four stocking densities (50, 75, 100, and 150 individuals/m3) to evaluate growth performance, water quality, and intestinal bacterial community composition. Growth traits and survival were recorded, water quality variables were monitored during culture, and gut bacterial communities were characterized by 16S rRNA gene sequencing. Increasing stocking density significantly reduced final body length, final body weight, weight gain rate, specific growth rate, and survival (P < 0.05). Ammonia-N and nitrite showed upward trends in the medium- and high-density groups during the later culture stage, suggesting increased loading of the culture system. Alpha diversity of the intestinal bacterial community declined under higher stocking density, and principal coordinate analysis indicated compositional separation among treatments at day 40. Proteobacteria were the dominant phylum in all groups. The relative abundance of Vibrio increased in the higher-density groups, whereas Bacillus and Acinetobacter were relatively more abundant in the lower-density groups. PICRUSt2 output is reported here only as predicted functional potential rather than direct evidence of metabolic activity. Overall, the results indicate that excessive stocking density is associated with poorer production performance and altered gut bacterial community structure in Penaeus monodon under indoor culture conditions. Within the density range tested, lower to moderate stocking densities appeared more favorable for maintaining growth performance and a comparatively stable intestinal microbial profile.
Li et al. (Mon,) studied this question.