Fat Deposition, Fatty Acid Composition, and Its Relationship with Meat Quality and Human Health

The consumer’s profile has changed, and in recent years, there has been a greater concern for the nutritional quality of meat, especially in relation to fat that compose it. The meat fat composition can contribute to the onset of cardiovascular disease. On the other hand, fat is an essential component in the human diet, as well as providing energy; it contains essential fatty acids (FAs) that must be present in food. The meat nutritional properties are largely related to its fat content and fatty acid composition. In addition, fat gives flavor to food, helps in the absorption of vitamins, and plays an important role in the immune response, for humans, and animals. The fat nutritional and sensory quality in meat that is determined by the fatty acid composition can affect the degree of fat saturation, the storage stability, and flavor. There are several factors that can influence the fatty acid composition, such as animals’ species, breed, sex, and diet, causing various changes in carcass, as well as in tissues and chemical meat composition

Effect of the growth rate in the pre-weaning, post-weaning and finishing periods on carcass traits and meat quality of Nellore cattle

Objetivou-se avaliar as características de carcaça e carne de bovinos Nelore terminados em confinamento, submetidos a distintos ganhos de peso alto (H) e baixo (L) no período pré-desmame (PREW) e pós-desmame (PROW). Os animais foram separados em quatro tratamentos: PREW_H, PREW_L, PROW_H e PROW_L. Foram utilizados 283 bovinos machos, não castrados, inseridos no Programa da Associação Nacional de Criadores e Pesquisadores (ANCP). As comparações das taxas de ganhos foram realizadas com base em grupos de animais agrupados por ano de nascimento e época (seca ou chuvas) do ano, os quais foram manejados de forma similar dentro de um determinado rebanho, formando 20 grupos de contemporâneos do desmame ao sobreano, e em seguida criados na fase da cria e recria em sistema a pasto, suplementados com sal mineral e terminados em confinamento por 90 dias. Durante o confinamento, a relação volumoso:concentrado variou de 50:50 a 30:70, dependendo da fazenda. A dieta dos animais consistiu de silagem de milho integral ou de planta de sorgo, além de milho em grãos e / ou sorgo moído como concentrado energético e soja como concentrado proteico. O grupo de contemporâneos ao desmame foi composto por animais pertencentes à mesma fazenda, ano de nascimento, grupo de manejo ao pré-desmame e sexo, e o grupo de contemporâneo pós-desmame por animais pertencentes à mesma fazenda, ano de nascimento, grupo de manejo ao sobreano e sexo. Os animais foram classificados em: PREW_L e PREW_H, obtida pela diferença entre o peso ajustado aos 120 e 240 dias de idade e PROW_L e PROW_H, calculada pela diferença entre o peso ajustado aos 240 e 450 dias de idade. Para a análise da qualidade da carcaça e da carne, utilizou-se um total de 46 animais (PREW_L = 26, PREW_H = 20, PROW_L = 30 e PROW_H = 16) e peso vivo final de abate 580 ± 65,17 kg. Os animais foram selecionados considerando os valores extremos de desempenho dentro dos grupos a serem terminados em confinamento e posteriormente abatidos aos 24 meses de idade. No abate, foram avaliados o peso da carcaça quente (HCW), rendimento de carcaça quente (DP), e para a identificação do tipo de fibra muscular (MyHC) por SDS-PAGE foram coletadas amostras do músculo Longissimus thoracis (LT) e Semitendinosus (ST). Durante a desossa analisou-se o valor do pH 24 horas, área de olho de lombo (REA), espessura de gordura subcutânea (FT) e marmorização (MARM). Amostras do músculo LT entre as 12ª e 13ª costelas foram coletadas para análises da força de cisalhamento (WBSF), maturadas por sete dias a 0-2ºC, perdas por cocção (CL), cor da carne, perfil de ácidos graxos (FA), lipídeos totais (LT), colesterol (Cho), comprimento de sarcômero (SL), colágeno total (TCol), colágeno solúvel (SCol) e colágeno insolúvel (ICol). Após as análises, constatou-se que a taxa de ganho de peso influenciou o HCW, FT e SL (p < 0.05). No entanto, não foram observadas diferenças para pH, REA, MARM, WBSF, cor da carne e LT (p > 0.05). A carne de animais PROW_H apresentou melhor porcentagem de alguns ácidos graxos considerados desejáveis à saúde humana (p < 0.05). Observamos poucos resultados para a interação da taxa de ganho de peso entre as fases PREW x PROW para o ácido vacênico (18:1 trans-11), EPA- Eicosapentaenoico, (22:5 n3), ácido graxo linolênico conjugado CLA e isomêro CLA trans 10 cis 12. A taxa de ganho de peso não influenciou o Cho, tipo de fibras MyHC (I e II) e componentes do tecido conjuntivo (TCol, ICol e SCol) (p > 0.05). No entanto, para o TCol foi encontrada correlação negativa com HCQ, CL, MyHC-I, e correlação positiva para MyHC-II. Os resultados desse estudo mostram que a utilização de critérios de seleção, como taxa de ganho de peso nas fases pré e pós-desmame, em bovinos Nelore, poderia ser uma alternativa na obtenção de bons índices de qualidade de carne e características de carcaça. Sendo assim, a taxa de ganho de peso para as características de carcaça melhoradas, como HCW, SL e alguns perfis de FA, sugerem que os animais PROW_H apresentaram carne favorável à saúde humana, com condições de atender a demanda do consumidor por produtos de alta qualidade e da indústria de carne bovina.The objective of this study was to evaluate the carcass, and meat traits of Nellore cattle finished in a feedlot, submitted to different high (H) and low (L) weight gains in the pre-weaning (PREW) and post-weaning (PROW) periods. The animals were separated into four treatments: PREW_H, PREW_L, PROW_H, and PROW_L. Data of 283 non-castrated males from the National Association of Breeders and Researchers Association (ANCP, Ribeirão Preto, Brazil) were used. Comparisons of weight gain rates were made based on groups of animals grouped by year of birth and season of the year, which were handled similarly within a given herd, forming 20 contemporary groups from weaning to yearling, and then reared at the stage of rearing and rearing in a pasture system, supplemented with mineral salt and finished in confinement for 90 days. During the feedlot period, the forage: concentrate ratio ranged from 50:50 to 30:70, depending on the farm. The animals\' diet consisted of whole corn silage or sorghum plant, in addition to corn grain and/or ground sorghum as an energy concentrate and soy as a protein concentrate. The contemporary groups at weaning were composed of animals belonging to the same farm, year of birth, weaning management group, and sex. The post-weaning contemporary group was formed by animals belonging to the same farm, year of birth, group of yearling management, and sex. The animals were classified into PREW_L and PREW_H by the difference between the adjusted weight at 120 and 240 days of age and PROW_L and PROW_H, calculated by the difference between the adjusted weight at 240 and 450 days of age. For the analysis of carcass and meat quality, a total of 46 animals (PREW_L = 26, PREW_H = 20, PROW_L = 30, and PROW_H = 16) and final live weight 580 ± 65.17 kg were used. The animals were selected considering the extreme performance values within the groups to be finished in feedlot and subsequently slaughtered at 24 months of age. At the slaughterhouse, we measured the hot carcass weight (HCW), hot carcass yield (DP), and collected samples of the Longissimus thoracis (LT) and Semitendinosus (ST) muscle samples to identify the type of muscle fiber (MyHC) by SDS-PAGE. During deboning, the pH value was analyzed 24 hours, the rib eye area (REA), subcutaneous fat thickness (FT), and marbling (MARM). Samples of the LT muscle between the 12th and 13th ribs were collected for shear force analysis (WBSF), matured for seven days at 0-2º C, cooking losses (CL), meat color, fatty acid profile (FA), total lipids (LT), cholesterol (Cho), sarcomere length (SL), total collagen (TCol), soluble collagen (SCol) and insoluble collagen (ICol). After the analysis, it was found that the weight gain rate influenced HCW, FT, and SL (p< 0.05). However, no differences were observed for pH, OER, MARM, WBSF, meat color, and LT (p> 0.05). The meat of PROW_H animals showed a better percentage of some fatty acids considered desirable to human health, (p <0.05). The statistical analyzes showed that there was an interaction of the weight gain rate between the PREW x PROW phases with the vaccenic acid (18: 1 trans-11), EPA- Eicosapentaenoic acid, (22: 5 n3), acid conjugated linolenic fat CLA and isomer CLA trans 10 cis 12. The rate of weight gain did not influence Cho, type of MyHC fibers (I and II), and connective tissue components (TCol, ICol, and SCol) (p> 0.05). However, for TCol a negative correlation was found with HCW, CL, MyHC-I, and a positive correlation for MyHC-II. The results of this study show that the use of selection criteria such as the rate of weight gain in the pre-and post-weaning phases in Nellore cattle could be an alternative to improve carcass and meat quality traits. Thus, the rate of weight gain for improved carcass traits, such as HCW, SL and FA, suggests that PROW_H animals presented meat favorable to human health, able to meet consumer demand for high-quality products and the meat industry beef

Fatty acid profile and meat quality of young bulls fed ground soybean or ground cottonseed and vitamin E

The objective of this study was to evaluate the fatty acid profile and qualitative characteristics of meat from feedlot young bulls fed ground soybean or ground cottonseed, with or without supplementation of vitamin E. A total of 40 Red Norte young bulls, with an initial average age of 20 months, and an initial average BW of 339 +/- 15 kg, were allotted in a completely randomized design using a 2 x 2 factorial arrangement, with two oilseeds, and daily supplementation or not of 2500 IU of vitamin E. The experimental period was for 84 days, which was preceded by an adaptation period of 28 days. The treatments were ground soybean (SB), ground soybean plus vitamin E (SBE), ground cottonseed (CS) and ground cottonseed plus vitamin E (CSE). The percentage of cottonseed and soybean in the diets (dry matter basis) was 24% and 20%, respectively. Diets were isonitrogenous (13% CP) and presented similar amount of ether extract (6.5%). The animals were slaughtered at average live weight of 464 +/- 15 kg, and samples were taken from the longissimus dorsi muscle for the measurement of fatty acid concentration and the evaluation of lipid oxidation and color of the beef. Before fatty acid extraction, muscle tissue and subcutaneous fat of the longissimus dorsi were separated to analyze fatty acid profile in both tissues. Supplementation of vitamin E did not affect fatty acid concentration, lipid oxidation and color (P > 0.05). Subcutaneous fat from animals fed CS diet had greater C12: 0, C16: 0 and C18: 0 contents (P < 0.03). In addition, CS diets reduced the C18: 1 and C18: 2 cis-9, trans-11 contents in subcutaneous fat (P < 0.05). The muscle from animals fed CS tended to higher C16: 0 and C18: 0 contents (P < 0.11), and decreased C18: 1, C18: 2 cis-9, trans-11 and C18: 3 contents (P < 0.05) compared with SB. The Delta(9)-desaturase index was greater in muscle from animals fed SB (P < 0.01). At 42 days of age, meat from cattle fed SB had a greater lipid oxidation rate (P < 0.05). Meat from animals fed SB diets had less lightness and redness indices than meat from animals fed CS diets after 14 days of age. In conclusion, the addition of ground cottonseed in the finishing diets did increase the saturated fatty acid content of the longissimus dorsi. However, animals fed cottonseed exhibited greater lightness and redness of beef. In this study, the addition of vitamin E did not affect qualitative characteristics of meat