Effects of Different Feeding Regimes on Growth Rates and Fatty Acid Composition of Largemouth Bass Micropterus nigricans at High Water Temperatures.

Abstract

Simple SummaryThe Largemouth bass aquaculture industry is growing in the United States. Many producers are shifting toward raising small juvenile fish, referred to as fingerlings. During the summer months, when water temperatures are highest, producers need to know how to best feed their fingerlings to ensure the best growth. This study aimed to determine which feeding strategies and feed amounts can result in healthy fish growth with a desirable fat content while under heat stress. The results of this study indicate that feeding fingerlings a lower amount daily or feeding every other day will result in the most efficient growth. These results also allow producers to form an economic feeding plan for fingerlings when water temperatures are high.As the northern Largemouth bass (LMB) (Micropterus nigricans) industry shifts toward fingerling production, implementing practical feeding strategies to ensure efficient growth during high water temperatures is paramount. Twenty (12.7 ± 0.2 g) (Trial 1) and fifteen (7.2 ± 0.1 g) (Trial 2) LMB fingerlings were stocked in two recirculating systems (each containing nine tanks), acclimated to 30 °C, with one system fed daily rations of 3, 5 and 7% body weight (Trial 1), and the second system fed to satiation daily, every second day, or every third day (Trial 2), for 28 days each. All treatments were triplicated. Multiple growth metrics and lipid composition were analyzed. The 3% treatment yielded the lowest final average weight (36.05 g) and FCR (0.83), with no difference in final biomass in Trial 1 treatments. Fish fed to satiation daily and every second day produced FCRs and biomasses of 0.83 and 356.78 g, and 0.93 and 272.26 g, respectively. There were no differences in total lipid concentration, however, fatty acid profiles differed significantly between all treatments within their respective trials. Feeding LMB fingerlings 3% of total body weight or feeding daily to satiation allows for efficient growth at 30 °C and implements cost-effective feeding strategies.