Amazon river prawn larvae incorporate astaxanthin in response to dietary supplementation with Bixa orellana

This study evaluated the effects of dietary bixin, a carotenoid from Bixa orellana , on larval development, post‐larval performance, and carotenoid deposition in Macrobrachium amazonicum under controlled conditions. Larvae were reared in a recirculating aquaculture system with a moving bed biofilm reactor (MBBR) and fed Artemia nauplii and an inert diet. Two treatments were tested: a control diet and a diet supplemented with 1000 mg kg −1 annatto extract (172.75 mg kg −1 of bixin). Bixin supplementation increased pigmentation and astaxanthin accumulation in post‐larval tissues, indicating effective uptake and deposition of dietary carotenoids. However, at the tested inclusion level, it reduced metamorphosis rate and decreased post‐larval productivity, while total survival did not differ statistically between treatments. Additionally, post‐larvae from the supplemented group showed higher individual weight, although this result should be interpreted cautiously because it may reflect delayed developmental progression rather than improved growth performance. These findings indicate that bixin is a promising natural carotenoid source for M. amazonicum , but its effects are dependent on the inclusion level. Further studies are required to determine optimal dietary concentrations that balance pigment deposition, larval performance, and production efficiency.