Effects of Oyster Shell Addition on Shrimp Aquaculture and the Dynamic Succession of Surface Biofilm Microbial Communities

Abstract In the context of Litopenaeus vannamei aquaculture, the incorporation of oyster shells has proven beneficial for enhancing water quality and the growth conditions of the shrimp. Nonetheless, the specific effects of in-situ water treatment using oyster shells on water quality and shrimp growth, along with the composition and succession dynamics of the microbial community within oyster shell biofilms, have yet to be thoroughly investigated. This study established control, low-concentration, and high-concentration oyster shell addition groups to emulate the in-situ water treatment environment with oyster shells, with the objective of elucidating the impacts of oyster shell addition on the aquaculture setting. The results showed that the addition of oyster shells exerted positive influences on shrimp length, weight, and survival rate, without significant disparities between the high and low concentration groups. Additionally, oyster shell addition resulted in elevated phosphate levels, diminished nitrite levels, and increased nitrate concentrations. Within the biofilm, the relative abundances of Ruegeria, Tenacibaculum, BD2-11_terrestrial_group, and Kapabacteriales exhibited significant declines over time, whereas the relative abundance of Nitrospira demonstrated a marked increase, ultimately emerging as the predominant bacterium in the biofilm during the latter stages of the experiment. Nitrospira also exhibited a notably higher relative abundance in the microbial community of the experimental water group relative to the control group. This research offers valuable insights for the application of oyster shells in shrimp farming and contributes to the theoretical underpinnings necessary for advancing our understanding of the mechanisms through which oyster shell biofilms enhance water quality and foster shrimp health.