The Effects of Dietary Protein-to-Energy Ratio on Juvenile Bluegill (Lepomis macrochirus) Growth with Observations of Sexual Dimorphism

Bluegill is a promising aquaculture species in the Midwest. males are typically larger than females. However, there is little or no information on nutritional differences between sexes and protein-to-energy ratio. The objective of this study was to characterize the protein-to-energy ratio in juvenile bluegill with observations on gender differences. Bluegill (20-30g) were fed diets consisting of 35% protein with 14, 16, and 18% lipids and 38% protein with 12, 14, and 16% lipids. Four replicates of 12 fish each were fed the diets for 16 weeks. Terminal mean body weights, lengths, liver wights, visceral weights, hepatic somatics indices (HSI), and visceral somatic indices (VSI) were recorded. No differences were found in the mean body weights, lengths, or visceral weights among diets. Increased liver weights, HSI, and VSI were observed in treated with 35% protein. The study revealed sexual dimporphism in body weights, lengths, HSI, VSI, and visceral weights. When data were compared by sexes there were more differences and patterns than among diets compared by the overall means. No differences in the body weights and lengths were found among fish fed different diets. Liver characteristics of fish fed the 35% diets could indicate future fish growth problems. There is a need for further investigation of the effect of gender on feeding trials.https://bluetigercommons.lincolnu.edu/lucer-pubs/1005/thumbnail.jp