Global aquaculture production has increased almost 12 fold since 1980 and currently provides over half of the fish and shellfish directly consumed by humans. Considering that intensive aquaculture feed expenses generally account for 40-60% of total operational costs, reducing feed-related costs continues to be a priority for the economical sustainability of aquaculture operations and a prime subject for investigation. Indeed, the aquaculture feed industry is clamoring for cost-effective and widely-available protein feedstuffs for replacing fishmeal (FM). Plant-protein feedstuffs are promising alternatives for FM, and currently soybean meal (SBM) is the foremost plant-protein ingredient in aquaculture feeds, especially the conventional SBM (CSBM). However, in-depth research is still needed to increase CSBM utilization and optimize FM-free, CSBM-based diets for a range of finfish species.
Therefore, the objectives of this project are:
(1) to assess the effects of supplemental feed additives in CSBM-based diets on the production performance, gut micromorphology and physio-biochemical responses of largemouth bass (LMB);
(2) to investigate the effects of feed additives supplementation in CSBM-based diets on the expressions of growth, lipid metabolism, and immunity related genes of LMB. For this purpose, a complete randomized experimental design will be used to evaluate ten experimental diets (isonitrogenous, 42% and isolipidic, 12%) containing three different feed additives (palatability enhancer, prebiotic, and vitamin E) supplemented alone or in all possible combinations.
The project will be carried out in the Aquaculture Nutrition laboratory located in the Aquaculture Research Center of Kentucky State University (KSU). The feeding trial will be carried out using a recirculating aquaculture system comprised of 36 (110-L) glass aquaria. Homogeneous groups of feed-trained LMB juveniles will be stocked in each experimental aquarium and fed twice daily with one of the randomly assigned experimental diets to apparent satiation for a period ranging from 8 to 12 weeks.
In the end, the project is expected to:
(i) supply relevant information to feed companies, producers, nutritionists and industry stakeholders about the applicability of commercially available CSBM and key feed additives;
(ii) provide feedback to CSBM producing companies on its relative nutritional value for LMB;
(iii) expand the scientific information on the importance of continued research on potential replacers for FM in aqua-feeds; and
(iv) improve the knowledge and empower fish farmers to become strong decision makers in the aquaculture feed industry.