Growth, feed utilization and body composition of black catfish, Rhamdia quelen, fry fed diets containing different protein and energy levels
2004
Salhi, M. | Bessonart, M. | Chediak, G. | Bellagamba, M. | Carnevia, D.
In order to evaluate the protein and energy requirement of black catfish fry, eight experimental diets containing four protein levels (30%, 34%, 38% and 43%) and two lipid levels (8% and 14%) were tested. For 30 days, 0.3 g fish were fed the experimental diets to approximate satiation, twice a day. Growth was significantly affected by both protein and lipid content of the diets. At the same protein level, final mean weight, weight gain and specific growth rate (% per day) were significantly improved (P<0.01) by increasing the dietary lipid (energy) content. At the same dietary lipid content, final weight, weight gain and SGR obtained with diets containing 38% and 43% protein were similar and significantly (P<0.01) higher than those obtained with diets containing 30% and 34% protein. Feed conversion ratio was improved by increasing the dietary protein content, obtaining a value of 0.95 (fed/gain) with diets 38/14 and 43/14. Protein efficiency ratio (PER) was not significantly affected by the different dietary treatments for each dietary lipid or protein level tested, reaching a mean value of 2.80 in fish fed high lipid diets. Results obtained in the present study suggest that for black catfish fry, the optimum dietary protein content is 37% with an estimated optimum digestible protein (DP)/DE ratio of 23.6 mg kJ-1.
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