ABSTRACT The objective of the present study was to evaluate the stability of candidate reference genes and select the genes that can be used for normalizing real-time polymerase chain reaction (PCR) in the liver, skeletal muscle, and jejunum tissues of Nellore or Nellore × Angus steers fed different diets. Fourteen purebred and 14 crossbred steers were used, in which half of the animals of each genetic group received a diet containing whole shelled corn (WSC) and the other half whole shelled corn and sugarcane bagasse (WSCB). Stability was analyzed by the RefFinder program. To validate the selection of candidate reference genes, the expression of target genes was evaluated using the different groups of reference genes. The most stable genes were 18S, ACTB, and CASC3 for skeletal muscle; HMBS, ACTB, and 18S for the liver; and GAPDH, ACTB, and CASC3 for the jejunum, regardless of breed and diet provided. Possible errors caused in data analyses were clarified comparing the more and less stable genes as reference for normalization of the target genes FASN, ACOX, SCD1, MGAM, and SLC2A1. The use of the more stable and less stable sets of reference genes may lead to different conclusions in respect to the expression profile of the target studied gene. The selection of more suitable reference genes for each experiment is of utmost importance to ensure the reliability of gene expression studies so that they can be applied in practice.

ABSTRACT: This study aimed to evaluate the quality traits and fatty acid profile of beef from Nellore and Angus bulls fed whole shelled corn (WSC) and ground corn plus maize silage (GC) diets. Eighteen Nellore and 18 Angus young bulls [381 ± 12 kg initial body weight (BW) and an average age of 20 ± 1.9 months] were used in a completely randomized design using a 2 × 2 factorial arrangement and were slaughtered at a final BW of 451.5 kg and 545.5 kg, respectively. Twenty–four hours after slaughter, samples of longissimus thoracis muscle were collected for the analysis of lipid oxidation, color, fatty acid profile, shear force, and cooking loss. There was no effect of diet × breed interaction on meat color, lipid oxidation, shear force, and cooking loss. Angus beef had lower shear force (p < 0.05) than Nellore beef and had a greater concentration of linoleic acid and polyunsaturated fatty acids (PUFA) (p < 0.01). Beef of bulls fed WSC tended to have greater concentration of CLA C18:2c9t11 (p = 0.09), greater concentration of CLA C18:2t10c12 (p = 0.01), and PUFA (p = 0.05), and consequently, higher oxidation levels. Angus bulls produced beef with greater tenderness and PUFA concentration. The results of fatty acid show a possible change in biohydrogenation when animals are fed the WSC diet, reducing lipogenesis, as this diet increases the C18:2t10c12 content.

Avaliou-se o efeito de diferentes formas de processamento da casca de mandioca na alimentação sobre o desempenho e as características de carcaça, a morfologia ruminal e a viabilidade técnico-econômica da criação de ovinos. Foram utilizados 20 ovinos machos da raça Santa Inês, desmamados, com peso inicial de 19,02±0,21 kg e 90 dias de vida. O delineamento experimental foi inteiramente casualizado com cinco repetições por dieta. Durante o período experimental de 84 dias, incluindo 14 dias de adaptação, os animais foram mantidos em sistema de semiconfinamento em pastagem de Brachiaria decumbens. Foram avaliadas quatro formas de processamento da casca de mandioca: desidratada triturada em peneira de 12 ou de 5 mm; úmida triturada e ensilada; e úmida triturada e hidrolisada com 0,5% de cal virgem (óxido de cálcio - CaO). O peso médio ao abate foi 30,72±1,46 kg. Não houve influência do tipo de processamento da casca sobre as características de desempenho analisadas, as características quantitativas de carcaça e a morfologia ruminal, sendo influenciado somente o rendimento de paleta. A casca de mandioca hidrolisada foi a que promoveu melhor eficiência econômica. Os tipos de processamento da casca de mandioca não alteram o desempenho, as características de carcaça, os rendimentos de corte e a morfologia ruminal dos ovinos Santa Inês.

The objective of this trial was to evaluate the effect of different forms of processing of cassava peel in sheep feeding on performance traits, carcass, morphology and rumen and economic technical feasibility. Twenty non-castrated male Santa Ines lambs of 19.02±0.21 kg of initial body weight and 90 days of age at the beginning of the study were used in this trial. The design was completely randomized design with five replications per treatment. During the experimental period of 84 days, including 14 days of adaptation, animals were kept in semi-confinement on Brachiaria decumbens. Four forms of cassava peel processing were evaluated: dried cassava peel ground through 12-mm sieve; dried cassava peel ground through 5-mm sieve; ground and ensiled cassava peel, and wet, ground hydrolyzed with 0.5% lime (calcium oxide - CaO). The average weight at slaughter was 30.72±1.46 kg. There was no influence of the type of processing on the performance variables analyzed, quantitative carcass characteristics or ruminal morphology; only the values of width and leg yield palette were influenced. Hydrolyzed cassava peel showed the best economic efficiency between treatments. The different methods of processing cassava peel do not affect performance, carcass characteristics, yield cuts or rumen morphology of Santa Ines sheep.