Exigência em proteína bruta para larvas e juvenis de tambaqui (Colossoma macropomum) e o uso de mistura de aminoácidos cristalinos como substituto parcial da proteína
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Data
2016-02-04
Autores
Kojima, Juliana Tomomi [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Esta tese está dividida em três capítulos, sendo o primeiro uma revisão sobre os temas estudados e, os seguintes, os resultados da pesquisa, descritos na forma de artigos para publicação. Foram realizados dois experimentos para determinar a exigência proteica de larvas (ca. 70 mg de peso inicial) e juvenis pós-metamórficos (ca. 250 mg de peso inicial) de tambaqui Colossoma macropomum, e um experimento para determinar o nível máximo de subsituição da fração proteica das dietas semi-purificadas por uma mistura de aminoácidos cristalinos. Para o primeiro estudo de exigência proteica de tambaquis na primeira fase de desenvolvimento, seis dietas semi-purificadas com quantidades crescentes de proteína foram ofertadas (D36,4; D42,1; D47,5; D53,2; D62,0; D68,5), e para a segunda fase de desenvolvimento foram ofertadas sete dietas com quantidades crescentes de proteína (D19,9; D26,2; D31,9; D36,4; D42,1; D47,5; D53,2). Os níveis de 49,46 % e 31,9 % de proteína foram suficientes para atender às exigências em proteína bruta de larvas de tambaqui e juvenis pós-metamorfose, respectivamente. Os níveis de proteína afetaram o desenvolvimento das fibras musculares das larvas (P<0,05), enquanto os juvenis demonstraram diferenças de crescimento muscular entre os tratamentos somente para uma classe de diâmetro de fibra (P>0,05). No segundo estudo, foram utilizados juvenis de tambaqui com peso médio inicial de 200 mg e testadas cinco dietas com níveis crescentes de substituição do perfil de aminoácidos da fração proteica das dietas (caseína e gelatina) por uma mistura de aminoácidos cristalinos nos níveis de 0, 25, 50, 75 e 90 %. O desempenho e o perfil de aminoácidos livres na musculatura esquelética dos juvenis foram afetados com o aumento dos níveis de substituição. No entanto, o desenvolvimento das fibras musculares dos juvenis que receberam dietas com substituição (0 a 90 %) foi semelhante entre os tratamentos (P>0,05), diferindo somente para as fibras menores que 10 µm (P<0,05). Os juvenis que receberam as dietas com 25 e 50 % de substituição foram capazes de demonstrar crescimento semelhante aos juvenis do tratamento sem substituição. Desta forma, os resultados encontrados neste estudo poderão contribuir com estudos futuros relacionados à exigência nutricional específica para a fase inicial de desenvolvimento do tambaqui.
This thesis is divided into three chapters, the first one presents an overview of the state-of-art of the subject, and the others describe the results, written as articles for publication. Two experiments were conducted to determine the protein requirement of larvae (ca. 70 mg initial weight) and postmetamorphosis juveniles (ca. 250 mg initial weight) of tambaqui Colossoma macropomum, and another experiment was carried out to determine the maximum level of the protein fraction that could be replaced by a mixture of synthetic amino acids in semi purified diets. For the study of protein requirement of tambaqui in first stage of development, six semi purified diets with increasing levels of protein were offered (D36.4; D42.1; D47.5; D53.2; D62.0; D68.5). In second stage of development, seven semi purified diets with increasing levels of protein were offered to tambaqui juveniles (D19.9; D26.2; D31.9; D36.4; D42.1; D47.5; D53.2). The levels of 46.89 % and 30.65 % of crude protein were enough to meet the protein requirement of tambaqui larvae and postmetamorphic juveniles, respectively. Protein levels affect the development of muscle fibers in tambaqui larvae (P<0.05), and only one diameter muscle fiber class in the juveniles (P>0.05). In the second study, tambaqui juveniles with initial weight of 0.2 g were fed with five semi purified diets with increasing levels of protein (casein and gelatin) replacement by crystalline amino acids mixture at levels of 0, 25, 50, 75 and 90 %. The performance of juveniles and free amino acids profile in muscle were affected with increasing replacement levels (P<0.05). However, muscle fibers development of juveniles fed diets with protein replacement (0 to 90 %) was similar among treatments (P>0.05), differing only for smaller fibers than 10 µm (P<0.05). The juveniles fed diets with 25 and 50 % of replacement showed similar results than the juveniles of treatment without replacement. Thus, the findings of this study can contribute to future research of specific nutritional requirement for the initial development of tambaqui.
This thesis is divided into three chapters, the first one presents an overview of the state-of-art of the subject, and the others describe the results, written as articles for publication. Two experiments were conducted to determine the protein requirement of larvae (ca. 70 mg initial weight) and postmetamorphosis juveniles (ca. 250 mg initial weight) of tambaqui Colossoma macropomum, and another experiment was carried out to determine the maximum level of the protein fraction that could be replaced by a mixture of synthetic amino acids in semi purified diets. For the study of protein requirement of tambaqui in first stage of development, six semi purified diets with increasing levels of protein were offered (D36.4; D42.1; D47.5; D53.2; D62.0; D68.5). In second stage of development, seven semi purified diets with increasing levels of protein were offered to tambaqui juveniles (D19.9; D26.2; D31.9; D36.4; D42.1; D47.5; D53.2). The levels of 46.89 % and 30.65 % of crude protein were enough to meet the protein requirement of tambaqui larvae and postmetamorphic juveniles, respectively. Protein levels affect the development of muscle fibers in tambaqui larvae (P<0.05), and only one diameter muscle fiber class in the juveniles (P>0.05). In the second study, tambaqui juveniles with initial weight of 0.2 g were fed with five semi purified diets with increasing levels of protein (casein and gelatin) replacement by crystalline amino acids mixture at levels of 0, 25, 50, 75 and 90 %. The performance of juveniles and free amino acids profile in muscle were affected with increasing replacement levels (P<0.05). However, muscle fibers development of juveniles fed diets with protein replacement (0 to 90 %) was similar among treatments (P>0.05), differing only for smaller fibers than 10 µm (P<0.05). The juveniles fed diets with 25 and 50 % of replacement showed similar results than the juveniles of treatment without replacement. Thus, the findings of this study can contribute to future research of specific nutritional requirement for the initial development of tambaqui.
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Palavras-chave
Aminoácidos indispensáveis, Aminoácidos dispensáveis, Crescimento inicial, crescimento muscular, Dieta semipurificada, Níveis de proteína bruta, Indispensable amino acids, Dispensable amino acids, Initial growth, Muscle growth, Semi-purified diets, Crude protein levels