Turnover protéico, avaliação e predição da composição química da carcaça e do corpo vazio de bovinos 3⁄4 Zebu × 1⁄4 Holandês

• Ano de defesa: 2014
• Autor(a) principal: Rodrigues, Felipe Chaves
• Orientador(a): Valadares Filho, Sebastião de Campos
• Banca de defesa: Detmann, Edenio , Valadares, Rilene Ferreira Diniz
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Zootecnia
• Departamento: Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul
• País: BR
• Palavras-chave em Português: Bovino de corte - Carcaça; Bovino - Cruzamento; Bovino - Raças; Turnover protéico; 3-metil-histidina
• Palavras-chave em Inglês: Beef cattle - Housing; Cattle - Crossing; Cattle - Breeds; Protein turnover; 3-methylhistidine
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL::EXIGENCIAS NUTRICIONAIS DOS ANIMAIS
• Link de acesso: http://locus.ufv.br/handle/123456789/5815

This paper aimed to propose new models to forecast the chemical composition of the non- carcass component; evaluate the equations proposed by BR-Corte (2010) to predict chemical composition of carcass and empty body from bovines using variables of the body and the section between 9th and 11th ribs from data of crossbred animals 3&#8260;4 Zebu x 1&#8260;4 Dutch; and use 3-methilhistidine (3MH) excretion to study the muscle protein synthesis and degradation in both crossbred males and females, at different stages of growth. In chapter 1, the objectives were to develop equations to estimate the non-carcass components chemical composition and to evaluate the prediction equations of chemical composition of carcass and empty body from bovines, proposed by BR-Corte (2010). Data from 130 animals in three experiments (24 castrated males CM; 24 females; and 82 non-castrated males NCM). Over the three experiments, the slaughter procedure was the same, where the gastrointestinal tract was washed to determine the empty body weight and all components of the animal body were weighed individually. The right half carcass was completely dissected and the weight of flash, fat and bones was measured. A sample from both carcass and non-carcass components were collected to determine the chemical composition. The section between the 9th and 11th ribs (HH section) was removed from all castrated males, all females and from 50 non-castrated males and completely dissected to evaluate the chemical composition prediction equations of carcass and empty body from BR-Corte (2010). Equations to estimate composition of the ethereal extract (EE), crude protein (CP), mineral material, calcium, phosphorus, magnesium, sodium and potassium of non-carcass components were proposed. Also, the BR-Corte (2010) equations to crude protein and ethereal extract contents of carcass and empty body were tested and the ones that did not estimate accordingly the known values were readjusted. The equations from BR-Corte (2010) estimated rightly the EE content in carcass from CM, NCM and females; and the EE content in empty body from CM and females. Thus, the forecast equations of CP in carcass from CM, NCM and female; EE in empty body from NCM; and CP in empty body from CM, NCM and females were readjusted. In Chapter 2, the objective was to evaluate the protein synthesis and degradation from castrated males and females, using 3MH. 20 castrated males and 20 females were used. They were with an average age of 12 months and average initial weight of 299 kg for males and 266,7 kg for females. The animals were separated in four groups with eight animals each group (four females and four males) to be slaughtered at 30, 60, 90 and 120 days of confining. The animals were separated in a completely randomized design, in 4 x2 factorial scheme, being two gender condition (castrated males and females) and four confining periods (30, 60, 90 and 120 days). Eight animals (four of each gender) were slaughtered at the beginning of the experiment to determine the initial muscle protein and mass; and four animals of each gender were slaughtered at the end of each period of confining to determine muscle protein and mass. The diet consisted of 45% forage and contained 116.35 g of crude protein / kgDM. To assess protein degradation was performed total collection of urine for three days in all animals slaughtered at the end of each period of confinement for analysis of excretion of 3-methyl-histidine. The urine collection was performed five days before each slaughter. The concentration of 3-methylhistidine in mmol / mmol of creatinine in urine did not differ between males and females (P <0.44) and between periods of confining (P> 0.45). The fractional degradation rate was lower in males than in females (P <0.01) and higher for animals slaughtered at 60, 90 and 120 compared to the slaughter with 30 days of confinement (P <0.01), with no interaction between sex and period of confining (P> 0.38). For the fractional synthesis rate there was no interaction between sex and period of confining (P> 0.31) and sex effect (P> 0.10), but the effect of confinement period (P <0,0,1) was observed, which was lower for animals slaughtered at 30 days compared to the others. The fractional rate of increase showed no interaction between sex and period of confining (P> 0.34), being higher in males (P <0.03) and between different periods of confining (P <0.01), being higher for animals slaughtered at 120 days, followed by 90, 30 and 60 days of confining. It is concluded that the degradation rate is higher in females and the rate of increase is higher in castrated males with no difference between genders for the rate of protein synthesis, which was increased with days on feed.