Reduced protein intake in Procambarus clarkii fed diets containing graded levels of purslane: Effects on growth and quality

Abstract

Abstract In this study, 144 red swamp crayfish (Procambarus clarkii, initial mean weight 3.9 ± 0.3 g) juveniles were fed diets containing graded levels of purslane (Portulaca oleracea), with a decreasing percentage of proteins (from 17.3% to 1.0%) for 10 weeks. Six diets were administered: four fishmeal diets containing 5%, 15%, 25%, and 50% purslane, a diet with 100% purslane, and a commercial diet. Growth performance and the amounts of fatty acids and carotenoids were measured. Crayfish fed 25% and 50% purslane diets showed optimal contents in fatty acids (FAs) and astaxanthin, and their growth was comparable to that of the control group. Significant differences in FA content of the crayfish groups were observed for saturated FAs, monounsaturated FAs (MUFAs), and polyunsaturated FAs (PUFAs). The highest levels of n − 3 α‐linolenic acid (ALA) and n − 6 linoleic acid (LA) were found in the groups fed 25%, 50%, and 100% purslane diets. This study shows that the best purslane content to be included in the crayfish diet should range between 25% and 50%. Although the nutritional value of purslane is low, its inclusion at up to 50% in crayfish diets seems to improve the carotenoid content and FA quality, while reducing the daily intake of animal protein, without affecting growth performance, thus contributing to the goal of more sustainable crustacean aquaculture.

Keywords

• astaxanthin
• crayfish
• fatty acids
• Procambarus clarkii
• protein
• purslane