Dietary lipid requirement of redtail botia catfish (Yasuhikotakia modesta)

Abstract

This study aimed to determine the optimal dietary lipid level for improving growth performance and feed utilization efficiency of redtail botia catfish (Yasuhikotakia modesta). A feeding trial was conducted using a completely randomized design with five isonitrogenous diets (45% crude protein) containing graded lipid levels of 3%, 6%, 9%, 12%, and 15%, each with four replicates in 60 day. Juvenile fish with an initial body weight of 6.4 g were stocked in a recirculating aquaculture system and fed twice daily to apparent satiation. The results showed that SR remained high (95–100%) across all treatments, indicating that dietary lipid levels did not negatively affect fish survival. Growth performance was significantly influenced by dietary lipid level, with the highest final weight, weight gain, daily weight gain, and specific growth rate recorded at 9% lipid (p < 0.05). FI decreased with increasing dietary lipid levels, while FCR improved. However, LER and LR declined as dietary lipid increased, suggesting reduced lipid utilization at higher inclusion levels. Body lipid content increased significantly with increasing dietary lipid, whereas moisture content decreased. In addition, HSI decreased while VSI increased at moderate lipid levels, reflecting changes in lipid deposition patterns. In conclusion, regression analysis between the specific growth rate (SGR) of redtail botia catfish and dietary lipid content (y = -0.0041x² + 0.0805x + 0.6123; R² = 0.62), the optimal dietary lipid level was estimated to be 9.81% for maximizing growth performance and feed efficiency of redtail botia catfish.