Authors : Simon John Davies , Antonio Gouveia , Ahmet Adem Tekinay and Derya Guroy
Abstract: A 42 days feeding trial was undertaken to assess the modulation of rapeseed and cottonseed meals on dietary nitrogen utilization in the African catfish, Clarias gariepinus fed a reduced feed schedule simulating the practice of maintaining fish stock prior to intensive production on higher feeding regimes. Ten iso-nitrogenous (36% crude protein, N�6.25) and isocaloric diets were formulated. Two diets served as a reference formulation; one an all fishmeal based diet and the other a soybean meal/fishmeal combination. This latter protein combination was effectively replaced by 15, 30, 45 and 60%, respectively of each test ingredient. It was concluded that between 15 and 30% of the diet could be effectively replaced with rapeseed and cottonseed meals, respectively without detriment to Apparent Net Nitrogen Utilization (ANNU) and in respect of several other parameters i.e., Protein Efficiency Ratio (PER), Feed Conversion Ratio (FCR) and carcass composition. These were found to be in accordance with other reported data in the literature for African catfish. However, it was found that higher inclusion of these ingredients resulted in inferior ANNU. These ranged from 37.05-31.04% for rapeseed meal and from 32.59-17.72% for cottonseed meal. Findings are reported in the context of formulating low cost feeds for this species under holding conditions without detriment to their nutritional status.
Simon John Davies , Antonio Gouveia , Ahmet Adem Tekinay and Derya Guroy , 2008. Dietary Nitrogen Utilization in African Catfish, Clarias gariepinus Fed Oil Seed Meal Based Diets under Sub-Optimal Growth Conditions Consistent with a Restricted Feeding Regime. Journal of Fisheries International, 3: 98-104.