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Dietary Protein Requirement of Juvenile Cachara Catfish, Pseudoplatystoma reticulatum

Authors

  • Fernando Henrique Gomes Cornélio,

    1. Fish Nutrition Lab (LABNUTRI), Aquaculture Department, Agrarian Sciences Center, Federal University of Santa Catarina (UFSC), Florianópolis, Santa Catarina, Brazil
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  • Douglas Amaral da Cunha,

    1. Fish Nutrition Lab (LABNUTRI), Aquaculture Department, Agrarian Sciences Center, Federal University of Santa Catarina (UFSC), Florianópolis, Santa Catarina, Brazil
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  • Jennifer Silveira,

    1. Fish Nutrition Lab (LABNUTRI), Aquaculture Department, Agrarian Sciences Center, Federal University of Santa Catarina (UFSC), Florianópolis, Santa Catarina, Brazil
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  • Daniel Alexandre,

    1. Biochemistry Department, Biological Sciences Center, UFSC, Florianópolis, Santa Catarina, Brazil
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  • Carlos Peres Silva,

    1. Biochemistry Department, Biological Sciences Center, UFSC, Florianópolis, Santa Catarina, Brazil
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  • Débora Machado Fracalossi

    Corresponding author
    1. Fish Nutrition Lab (LABNUTRI), Aquaculture Department, Agrarian Sciences Center, UFSC, Florianópolis, Santa Catarina, Brazil
    • Corresponding author.

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Abstract

Cachara, Pseudoplatystoma reticulatum, is a high commercial value carnivorous catfish in Brazil, but whose dietary protein requirement is still unknown. Aiming to determine this requirement, groups of 15 juveniles (16.08 ± 1.13 g) were fed isoenergetic diets (4600 kcal/kg gross energy) with increasing levels of crude protein (30, 35, 40, 45, 50, and 55%). After 60 d, regression analysis revealed a quadratic effect (P < 0.05) of increasing dietary crude protein concentration on growth variables. The highest weight gain and specific growth rate as well as the best feed conversion were shown by fish fed the 50% crude-protein diet. Similarly, protease activities were significantly higher (P < 0.05) in fish fed 50% crude protein. However, the highest protein retention was observed in fish fed the 45% crude-protein diet. Protein and dry matter digestibilities did not differ (P > 0.05) for diets containing 40, 45, or 50% crude protein. Therefore, based on weight gain and at a dietary energy concentration of 4600 kcal/kg, the estimated protein requirement for juvenile cachara between 16 and 85 g is 49.25% crude protein. This is equivalent to 44.79% digestible protein and a gross energy to digestible protein ratio of 10.27 kcal/g.

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