USING EARLY NUTRITIONAL PROGRAMMING TO ENHANCE THE UTILIZATION OF PLANT BASED DIETS IN LARGEMOUTH BASS, Micropterus salmoides

Sustainable aquaculture should include replacement of fishmeal-based feed sources by plant-based ingredients. However, this approach is often impeded by poor growth in carnivorous fish such as largemouth bass (LMB, Micropterus salmoides) fed high levels of plant-based protein. Therefore, our overall goal of the present work was to develop alternative methods of utilizing the plant-based diets (PBD) for sustainable LMB production. When fish are exposed to PBD early in their life, they may accept them more efficiently at later stages (so called Early Nutritional Programing, ENP).

A three-phase (6 weeks each, 18 weeks total) experiment was designed to evaluate the ENP of plant-based diets in early juvenile LMB (Figure 1). Preceding the experiment, LBM hatched larvae were fed Artemia nauplii for four weeks and then 1000 larvae (average weight ~ 0.1 g) distributed into tanks 1 and 2 for the commencement of Phase I (500 larvae/tank, 100 L size). On phase I, fish-larvae stocked into tanks 1 and 2 were fed a fishmeal-based diet (FM) or PBD, respectively. On phase II fish from each tank were divided into 2 tanks (tanks 3 and 4, respectively). Fish in tanks 1 and 2 continued to be fed the FM and SBM diets, while fish in tanks 3 and 4 were fed PBD and FM diets, respectively. On phase III, tanks 1 and 2 remained unchanged, while fish in tanks 3 and 4 were fed the FM and SBM diets, respectively.

At the end of phase III, no significant differences were found for growth performance (Figure 2) and body composition of fish whereas significant differences in physiological parameters were observed. Overall, this study developed an alternative method of utilizing the PBD at an early stage of life, which can reduce the cost of largemouth bass production.