# The effect of different dietary canthaxanthin levels on water quality parameters, growth performance, biochemical indices, immunological responses, body composition, and metabolic profiles of oriental river prawn (Macrobrachium nipponense)

## TL;DR

Adding canthaxanthin to the diet of oriental river prawns improves their growth, immunity, and metabolism, with 150 mg/kg being the most effective level.

## Contribution

This study identifies 150 mg/kg canthaxanthin as optimal for enhancing growth, immune responses, and metabolic profiles in Macrobrachium nipponense.

## Key findings

- 150 mg/kg canthaxanthin improved growth indices and reduced feed conversion ratio in oriental river prawns.
- Canthaxanthin at 150 mg/kg enhanced immune responses, antioxidant activity, and intestinal microbiota in prawns.
- Canthaxanthin supplementation increased total carotenoid content and improved amino acid and fatty acid compositions.

## Abstract

•Canthaxanthin markedly increased growth and survival in Macrobrachium nipponense.•Canthaxanthin at 150 mg/kg in oriental river prawn diets improves immuno-physiological responses.•Canthaxanthin positively impacts digestive enzyme and antioxidant activities in M. nipponense.•Canthaxanthin at 150 mg/kg improved the intestinal microbiota of oriental river prawn.•Canthaxanthin enhanced total carotenoid content and metabolic responses in M. nipponense.

Canthaxanthin markedly increased growth and survival in Macrobrachium nipponense.

Canthaxanthin at 150 mg/kg in oriental river prawn diets improves immuno-physiological responses.

Canthaxanthin positively impacts digestive enzyme and antioxidant activities in M. nipponense.

Canthaxanthin at 150 mg/kg improved the intestinal microbiota of oriental river prawn.

Canthaxanthin enhanced total carotenoid content and metabolic responses in M. nipponense.

The current research aimed to evaluate the impacts of five levels of canthaxanthin (0, 50, 100, 150, and 200 mg/kg) on a total of 375 oriental river prawns, with a mean initial weight of 1.39 ± 0.07 g, over a period of 56 days. Upon completion of the culture period, the prawns were subjected to bioassays. Hemolymph was collected, and samples were taken from the hepatopancreas, intestine, muscle, and shell tissues for the analysis of physiological, biochemical, and immunological indices. The findings indicated that dissolved oxygen levels were notably increased with varying concentrations of canthaxanthin (P < 0.05), while other water quality parameters did not show significant variations (P > 0.05). The group receiving 150 mg/kg of canthaxanthin supplementation exhibited the highest growth indices and the lowest feed conversion ratio (FCR) (P < 0.05). The most of hemato-biochemical parameters exhibited a significant reduction in the groups that included canthaxanthin (P < 0.05), whereas the levels of high-density lipoprotein (HDL) and low-density lipoprotein (LDL) showed a notable increase when compared to the control treatment (P < 0.05). However, cholesterol, phosphorus, calcium, and uric acid levels remained unaffected by canthaxanthin supplementation (P > 0.05). The treatment group administered 150 mg/kg of canthaxanthin exhibited positive impacts on the majority of hemato-immune responses, in addition to enhancing the antioxidant status of the hepatopancreas. However, glutathione peroxidase (GPx) activity did not show significant differences across the experimental treatments (P > 0.05). Administering 150 and 200 mg/kg of canthaxanthin significantly enhanced total carotenoid content (TCC), digestive enzyme activity, intestinal microbiota, and carcass composition (P < 0.05). Gene expression related to growth, immune response, and metabolic processes showed significant increases in the canthaxanthin-fed treatments (P < 0.05). Additionally, groups supplemented with canthaxanthin demonstrated improved amino acid and fatty acid compositions (P < 0.05). In conclusion, the findings of this study suggest that incorporating 150 mg/kg of canthaxanthin into the diet of oriental river prawns positively impacts growth indices, as well as biochemical, immunological, and metabolic responses in this species.