Effect of Rearing Density and Feeding Regimes on Growth and Survival of African Catfish, Heterobranchus longifilis (Valenceinnes, 1840) Larvae in a Closed Recirculating Aquaculture System

Abstract

Heterobranchus longifilis larvae were reared over a 35 d period to evaluate the effects of stocking densities and feeding regimes on growth and survival. In experiment 1, larvae (12.3 ± 2.1 mg) were stocked into glass aquaria at densities of 1, 2, 5, 10, 15, 20, and 25 larvae L⁻¹. Larvae were fed on Artemia nauplii ad libitum. Significant variations in terms of growth performance and feed utilization occurred at all levels of density treatments. Specific growth rate (SGR), body weight gain (BWG), and feed efficiency (FE) of the larvae decreased significantly as density increased. However, survival rate increased with the increase of stocking density. In experiment 2, larvae (13.4 ± 1.1 mg) stocked at a density of 15 larvae L⁻¹, in the same conditions as experiment 1, were fed on three different regimes: Artemia nauplii; 35% protein beef brain; and 35% protein commercial catfish feed (CN⁺). SGR, BWG, and coefficient of variation (CV) of larvae fed on Artemia nauplii were significantly higher than those fed on beef brain and CN⁺. The survival rate of larvae fed on beef brain was significantly higher (88.40 ± 9.75%) than those of Artemia (69.21 ± 6.69%) and CN⁺ (40.40 ± 6.22%). The results of this study suggest that the optimum stocking density is 15 larvae L⁻¹ and the beef brain can be used as alternative feed to Artemia in rearing H. longifilis larvae.

KEYWORDS:

• Heterobranchus longifilis
• clariid catfish
• larvae rearing
• densities
• feeding
• growth
• survival

The authors thank the Directory of CRO (Centre de Recherches Océanologiques) for providing financial as well as the infrastructural facilities necessary for the study. Special thanks to the students of CRO for assistance throughout this study.