Cottonseed protein concentrate as fish meal substitution in fish diet: a review

Aquaculture has been challenged to explore fish meal (FM) alternative proteins to develop efficient feed formulations that foster a sustainable future growth. Among them, cottonseed protein concentrate (CPC) is an innovative source of substantial non-edible protein with a high output, derived from agricultural by-products. It possesses enhanced nutritional benefits and appealing taste, attributed to the progressive advancements in cottonseed processing machinery and production techniques. Moreover, the levels of anti-nutritional factors (ANFs) such as gossypol are minimized, rendering CPC more easily digestible and assimilable by fish. The effect of dietary CPC on the growth performance, flesh quality, hematological and antioxidant indices, intestinal health and microbiota, and immune response of farmed fish has been well demonstrated in various fish species, suggesting the appropriate level for replacing FM with CPC varied across the fish species and the FM contents in the basic diet. Nevertheless, certain issues including the imbalanced amino acid composition, and the cumulative presence of gossypol when the diet containing abundant CPC should be concerned. In this review, we provide an overview of the nutritional components, key ANFs of CPC, and explore its use in fish nutrition. Furthermore, we deliberate on effective strategies to enhance its efficacy as a protein supplement in fish feed. This review establishes a scholarly groundwork and offers pragmatic direction for the investigation and implementation of CPC in fish feeding practices, thereby advocating for a decrease in the utilization of FM in aquaculture.