Astaxanthin biosynthesis pathway, carotenoid accumulation, and enhancement strategies in commercially important aquaculture species

Abstract

Can aquaculture producers enhance the natural pigmentation of commercially valuable species through targeted nutritional interventions? This research examined the astaxanthin biosynthesis pathway and carotenoid accumulation patterns across six commercially important aquaculture species. The investigation encompassed rainbow trout, Atlantic salmon, coho salmon, red sea bream, kuruma prawn, and Pacific white shrimp reared under controlled laboratory conditions. Astaxanthin content in muscle tissue ranged from 3.17 to 8.94 mg/kg wet weight, while skin and exoskeleton tissues demonstrated concentrations between 9.84 and 22.17 mg/kg. Three dietary enhancement strategies were evaluated over a twelve-week feeding trial: synthetic astaxanthin supplementation, Haematococcus pluvialis microalgae extract, and Phaffia rhodozyma yeast biomass. Results indicated that H. pluvialis extract produced the highest tissue pigmentation, achieving 17.3 mg/kg in muscle tissue compared to 11.7 mg/kg with synthetic supplementation and 10.9 mg/kg with P. rhodozyma. Gene expression analysis revealed upregulation of key biosynthetic enzymes including beta-carotene ketolase and beta-carotene hydroxylase following natural source supplementation. These findings support the commercial application of microalgae-derived astaxanthin for improving product quality and market value in aquaculture operations.