Evaluation of heat-processed cocoa pod husk meal as an energy feedstuff in production diets for the clariid catfish, Clarias isheriensis (Sydenham)

Abstract

Isoproteic and isoenergetic diets containing 0%, 15%, 30% or 45% heat-processed cocoa pod husk meal (CPHM) were fed to Clarias isheriensis (16.8 ± 2.4 g) for 180 days. Growth rates of catfish fed varying levels of CPHM were similar (P > 0.05). Differences in feed-gain ratio (FGR) or protein efficiency ratio (PER) between treatments were not significant (P > 0.05). Histology of the liver showed no pathological effects of incorporation of CPHM. In a second experiment, C. isheriensis (19.1 ± 3.5 g) were fed isoenergetic diets containing 250, 300, 350 and 400 protein g kg−1 (protein: energy ratios of 21, 25, 29 and 33 mg protein.kJ−1 DE, respectively). Growth rate and FGR improved (P < 0.05) in proportion to the dietary protein level. PER decreased with increase in dietary protein. Carcass protein was lowest (P < 0.05) in catfish fed 250 g protein kg−1, but did not differ among the other diets (P > 0.05). Body fat was highest in catfish fed 250 g protein kg−1 and lowest in fish fed 350 g protein kg−1. These results indicate that CPHM may be a suitable carbohydrate energy source for clariids at a P:E ratio of approximately 29 mg protein.kJ−1 DE.