Dietary threonine requirement to optimize protein retention and fillet production of fast‐growing Nile tilapia |
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| Authors: | M Michelato LVO Vidal TO Xavier TS Graciano LB De Moura VRB Furuya WM Furuya |
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| Affiliation: | 1. PPZ/UEM‐ Programa de Pós‐Gradua??o em Zootecnia, Universidade Estadual de Maringá, Maringá, Brazil;2. Departamento de Zootecnia, Universidade Federal da Bahia, Salvador, Brazil;3. Departamento de Zootecnia, Universidade Estadual de Ponta Grossa, Brazil |
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| Abstract: | Threonine is the third‐limiting essential amino acid in diets based on cereal ingredients. A 4‐week trial was conducted to determine the threonine requirement of large Nile tilapia based on fish growth, feed efficiency, body composition, protein and amino acid retention. Six hundred fish (563.3 ± 15.1 g) were distributed into twenty 1.2‐m3 cages. Five diets containing 288 g kg?1 of crude protein, 12.7 MJ kg?1 of digestible energy and 8.9, 10.5, 12.2, 13.7 and 15.4 g kg?1 of threonine were elaborated. Fish were hand‐fed five times a day to extruded diets. Significantly, differences in growth performance and amino acids retention among the treatments were observed. Fish fed 10.5 g kg?1 of threonine showed higher daily weight gain, gutted weight and fillet weight (P < 0.05) compared to fish fed with other experimental diets. Diets containing 8.9–15.4 g kg?1 of threonine did not affect whole body and muscle proximate composition. Based on second‐order regression analysis, the dietary threonine requirement estimated based on final gain, fillet weight and fillet yield was 12, 12.1 and 11.5 g kg?1 diet, respectively. The dietary threonine requirement for maximum fillet yield of Nile tilapia was estimated to be 11.5 g kg?1. |
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| Keywords: | amino acid retention body composition feed utilization growth performance threonine requirement |
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