Effect of background color on the growth performance, digestive enzyme activity, antioxidant capacity, and intestinal microbiota of juvenile Plectropomus leopardus

The scale of Plectropomus leopardus breeding is continually expanding, and this has necessitated constant changes to ensure that breeding conditions are optimized. Background color is an important factor affecting fish feeding. In this study, fish (10.58 ± 0.03 g) were cultured on five background colors (red, blue, black, white, and transparent), and the growth status and intestinal microbes of these fish over 56 days were analyzed. Growth performance and the expression of growth-related genes were optimized when the background color was white. The white group had higher AMS and LPS enzyme activities and lower T-SOD and T-AOC enzyme activities, indicating that the white background could effectively promote feeding and reduce oxidative stress in P. leopardus. Additionally, changes in background color altered the composition and function of the intestinal microbiota. The diversity and abundance of intestinal microbiota, including the abundance of beneficial bacteria, were highest in fish on a white background. The abundances of Firmicutes and Actinobacteriota and the abundance of Bacillus were higher in the White group than in the other groups, indicating that a white background promotes the health of juvenile P. leopardus. In conclusion, a white background can promote the growth performance of P. leopardus and increase the abundance of beneficial intestinal microbes. Generally, the results of our study could be used to optimize the culture of P. leopardus.