This study aimed to evaluate the development and the increase in the skin pigmentation of the organism Heros severus cultured in a biofloc system with diets enriched with carotenoid pigments. The culture was made in 80 L water tanks with 20 juvenile organisms of H. severus; each treatment was made by duplicate. Four experimental diets were used: a) trout feed, El Pedregal®; b) TetraColor®; c) carrot and d) beetroot. The diet that obtained the highest values regarding the growth of the fish was the control diet. Regarding the coloration of the fish, the beetroot diet was the diet that presented the highest values with 9.55 μg of total carotenoids in tissue, presenting significant differences (P = 0.001) concerning the other diets, proving that a diet based on beetroot can be a good option for the culture of ornamental fish. Because it allows the organisms to have a survival rate above 90%, have similar growth to the control group, and a significant improvement in coloration, being a natural carotenoid low-cost source to improve the commercialization of organisms. Nevertheless, it did not present significant differences (P = 0.005) regarding beetroot and TetraColor® diets, while it presented significant differences with the carrot diet.

Tilapia (Oreochromis niloticus) is one of the most important species in aquaculture, so the optimization of its culture by using sustainable strategies is fundamental. The aim of this study was to evaluate the effects of incorporating natural pigments (carrot and beetroot meal) as carbon sources in a biofloc system on the growth, immune response, and oxidative stress of O. niloticus. The experiment comprised four treatments: clear water as control (CT), biofloc with molasses (TBM), biofloc with carrot meal (TBC), and biofloc with beetroot meal (TBB). Results showed that biofloc helped to maintain optimal water quality and high survival rates, but specifically, TBC treatment achieved the highest growth rates and feed conversion ratio, along with elevated leukocyte counts, indicating improved health and immunity. Gene expression analysis revealed enhanced antioxidant activity (sod, gpx) and modulated immune responses (tnf-α, il-1β), particularly under thermal stress. Carrot meal emerged as an effective carbon source in biofloc systems, promoting growth, immune resilience, and oxidative stress resistance in tilapia, while beetroot meal improved pigmentation. These findings highlight the potential of natural pigments to enhance aquaculture sustainability and productivity.