Avaliação de farinhas de sangue como fonte de proteína para tilápia do Nilo (Oreochromis niloticus)
Carregando...
Data
2006-07-14
Autores
Narváez-Solarte, William Vicente [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Objetivou-se avaliar as farinhas de sangue representando as classes de processamento em tambor (FST), convencional (FSC) e atomização da fração celular do sangue (FCSA). As amostras das farinhas de sangue foram submetidas ao processo de extração e fracionamento da proteína para determinação do perfil do tamanho molecular, que foi comparado com o padrão obtido a partir de sangue bovino in natura. Nas diferentes amostras foram realizadas análises da digestibilidade in vitro da proteína, submetidas ou não ao processo de desengorduramento, para avaliar a qualidade da proteína e efeito do método de análise. Foram utilizados juvenis de tilápia do Nilo com peso médio inicial de 100,0 5,0g, submetidos aos tratamentos, num delineamento em blocos casualizados, com quatro repetições e 10 peixes por unidade experimental. Foram feitas quatro rações, sendo uma sem a suplemetação de farinha de sangue, usada como ração controle (purificada), servindo como referência para determinação dos coeficientes de digestibilidade dos nutrientes in vivo. As rações testes foram formuladas de maneira que cada uma das farinhas de sangue em estudo substituísse 30% da ração purificada. O processamento afetou a estrutura protéica original do sangue in natura em condições de alta temperatura e tempo prolongado, efeito traduzido pela alta proporção de peptídeos de baixo peso molecular e aminoácidos livres, correspondendo a baixos valores de digestibilidade da proteína da farinha de sangue em testes in vivo e in vitro. A FCSA e FST são eficientemente utilizadas pela tilápia-do-Nilo, sendo a FSC a proteína com valor biológico inferior ao das outras duas farinhas testadas. Dentre os aminoácidos, deve ser considerada a isoleucina como primeiro limitante na formulação de dietas para a tilápia-do-Nilo com o uso de farinha de sangue, seguida pela metionina+cistina, arginina e treonina...
An experiment was conducted to evaluate three kinds of blood meal coming from different processing conditions, spray-dried bovine blood cells (SDBC), drum-dried blood meal (DDBM) and vat-dried blood meal (VDBM). Protein extraction and fractionation was done on each blood meal type to determine the molecular weight profile of the protein. These profiles were compared to a standard obtained from bovine blood in natura. An in vitro digestibility analysis of the protein in the diets, with normal fat content or fat extracted, was carried out to evaluate the protein quality and the effect of the method used in the analysis. To determine the apparent digestibility coefficients (ADC) of the blood meal nutrients in vivo, Nile-tilapia juveniles, 100.00l5.0g/fish average weight, were held in 250 liters tanks that were randomly assigned to each experimental unit. Four replicates with 10 fish per experimental unit were used in a randomized block design. The ADC were determined using a reference diet (purified) with chromic oxide as indicator and the test diet that contained 70% reference diet, by weight, and 30% of the blood meal being evaluated. Results of this study show that protein structure of the blood in natura is affected by high temperature and length of time of processing, resulting in an increase in the amount of low molecular weight peptides, and free amino acids, corresponding to low values of blood meal protein digestibility, both in- vivo and in- vitro tests. SDBC and DDBM are efficiently used by the Nile-tilapia, indicating that VDBM has a lower protein value than those of the two other blood meal types. Isoleucine is the first limiting amino acid in diets that use blood meal as a source of proteins to feed Nile-tilapia, followed by methionine + cystine, arginine, and threonine, which are found in critical levels for this specie, mainly in the VDBM.
An experiment was conducted to evaluate three kinds of blood meal coming from different processing conditions, spray-dried bovine blood cells (SDBC), drum-dried blood meal (DDBM) and vat-dried blood meal (VDBM). Protein extraction and fractionation was done on each blood meal type to determine the molecular weight profile of the protein. These profiles were compared to a standard obtained from bovine blood in natura. An in vitro digestibility analysis of the protein in the diets, with normal fat content or fat extracted, was carried out to evaluate the protein quality and the effect of the method used in the analysis. To determine the apparent digestibility coefficients (ADC) of the blood meal nutrients in vivo, Nile-tilapia juveniles, 100.00l5.0g/fish average weight, were held in 250 liters tanks that were randomly assigned to each experimental unit. Four replicates with 10 fish per experimental unit were used in a randomized block design. The ADC were determined using a reference diet (purified) with chromic oxide as indicator and the test diet that contained 70% reference diet, by weight, and 30% of the blood meal being evaluated. Results of this study show that protein structure of the blood in natura is affected by high temperature and length of time of processing, resulting in an increase in the amount of low molecular weight peptides, and free amino acids, corresponding to low values of blood meal protein digestibility, both in- vivo and in- vitro tests. SDBC and DDBM are efficiently used by the Nile-tilapia, indicating that VDBM has a lower protein value than those of the two other blood meal types. Isoleucine is the first limiting amino acid in diets that use blood meal as a source of proteins to feed Nile-tilapia, followed by methionine + cystine, arginine, and threonine, which are found in critical levels for this specie, mainly in the VDBM.
Descrição
Palavras-chave
Tilapia (Peixe), Farinha como alimento, Sangue animal como alimento, Sangue - Analise e quimica, Aminoacidos, Amino acids, Blood meal, Degradation, Digestibility, Protein
Como citar
NARVÁEZ-SOLARTE, William Vicente. Avaliação de farinhas de sangue como fonte de proteína para tilápia do Nilo (Oreochromis niloticus). 2006. ix, 74 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Medicina Veterinária e Zootecnia, 2006.