A Dynamic Simulation Model for Growth of the African Catfish, Clarias Gariepinus Burchell 1822. II. Effect of Feed Composition on Growth and Energy Metabolism

Abstract

To investigate the effect of feed composition on growth of the African catfish a dynamic simulation model was adapted. The effect of feed composition studied was restricted to the effect of the macronutrients, i.e. protein, fat and carbohydratesMost parameters used in the model were derived from literature. Parameters, which were expected to have specific values for the species used or which could not be derived from the literature, were calibrated with experimental results. Results used for calibration originate from a 84day feeding trial with twenty different semi-moist diets. Protein content of these diets varied from 20 to 60% and fat content from 0 to 38%Data used to test the model originate from balance respiration experiments. In these experiments dietary protein content varied from 20 to 40% and fat content from 4 to 29%. A dry pelleted feed was usedThe test results of the model for growth, protein and fat gain, and oxygen consumption were compared with the independently obtained results of the balance respiration experiments. The predicted values are in agreement with the observed values, except for the diets with the highest fat content. At these diets predictions are overestimated. During the modelling procedures it became apparent that feed intake is influenced by the fat percentage of the fish. Fat fish consume less than leaner fish of the same weight.It is concluded that the model predicts reasonably well effects of feed composition on growth