Márcio Machado Ladeira

Fatty acid profile and qualitative characteristics of meat from zebu steers fed with different oilseeds

The objective of this study was to evaluate the effects of dietary addition of ground oilseed sources on the quality, fatty acid profile, and CLA content of meat from zebu steers. Thirty-one zebu steers with an initial average age of 23 mo and an initial BW of 365 kg were used in this study. The experimental period was 84 d, which was preceded by an adaption period of 28 d. The diet was provided ad libitum with a forage:concentrate ratio of 40:60. Corn silage was used as the forage source. Four different concentrates were formulated for each treatment: without additional lipids (control) or with ground soybeans (SB), ground cottonseed (CS), or ground linseed (LS). The SB, CS, and LS diets were formulated to have 6.5% ether extract on a total dietary DM basis. The experiment was set up as a completely randomized design. After slaughter, samples were taken from the longissimus thoracis muscle for the measurement of fatty acid concentration and the evaluation of meat quality. The luminosity index was greater in the control and LS diets (P < 0.01). The greatest percentages of myristic acid (C14:0), palmitic acid (C16:0), trans octadecenoic acid (C18:1 trans-10, trans-11, or trans-12), and SFA in the subcutaneous fat were observed in the CS treatment (P < 0.01). Moreover, the least percentages of oleic acid (C18:1 cis-9) and total unsaturated fatty acids in the subcutaneous fat were observed in the CS diet (P < 0.01). The meat linoleic acid and α-linolenic acid percentages were greatest in the SB and LS treatments, respectively (P < 0.001). The unsaturated fatty acid:SFA ratio was smallest for the CS diet (P < 0.01). A gradual increase in oxidation was observed as a function of storage time; however, the diets did not affect the rancidity of the meat (P > 0.05). The fatty acid profile of subcutaneous fat was impaired by the addition of CS. Supplying ground oilseeds did not increase the content of CLA in the meat.

Fatty acid profile, color and lipid oxidation of meat from young bulls fed ground soybean or rumen protected fat with or without monensin.

The objective of the present study was to evaluate the meat quality and fatty acid (FA) profile of the muscle and subcutaneous fat of young bulls fed ground soybean grain (SB) or rumen protected fat (RPF) with (230 mg head(-1) day(-1)) or without monensin. Forty animals with an initial weight of 359 kg were allotted in a 2×2 factorial arrangement of treatments. The use of monensin increased the arachidonic and α-linolenic acids in the longissimus dorsi (LD) muscle and subcutaneous fat, respectively (P<0.05). The meat from the animals receiving RPF had greater C18:1 content (P<0.01). The CLA and C18:2 contents were greater in the LD muscle of the animals fed SB (P<0.01). However, α-C18:3 was greater in the LD muscle of animals fed RPF (P<0.01). In the subcutaneous fat, SB reduced C12:0 and C14:0 contents (P<0.01) and increased C18:0 (P<0.05). The inclusion of RPF increased the C18:1 and CLA contents (P<0.01) in the subcutaneous fat. Soybean elevated PUFA contents and increased susceptibility of muscle and subcutaneous fat to lipid oxidation.

Qualitative characteristics of meat from young bulls fed different levels of crude glycerin

The objective was to evaluate the fatty acid profile and qualitative characteristics of meat from young bulls fed crude glycerin. Forty-four animals with an initial live weight of 368 ± 4 kg were used in a completely randomized design, with four treatments: no glycerin or addition of 6, 12 or 18% glycerin. The animals were slaughtered with 519.5 ± 14.9 kg of live weight. The meat characteristics assessed were chemical composition, shear force, fatty acid concentration, color and lipid oxidation. The addition of glycerin increased the content of ether extract (P<0.05) in the muscle. A linear increase was observed (P<0.05) in the oleic acid contents (C18:1 cis 9). The saturated fatty acid (SFA) contents linearly decreased in the muscle as a function of glycerin addition. The lightness (L*) and yellowness (b*) indices increased with the use of crude glycerin (P<0.05). The crude glycerin increased the intramuscular fat and oleic acid content in the longissimus dorsi muscle.

Effects of dietary fat sources on intake, nutrient digestibility and plasma urea nitrogen for lactating water buffaloes.

The effects of fat sources on intake, nutrient digestibility and plasma urea nitrogen were evaluated in lactating water buffalo. Twelve females were randomly distributed into four treatments: without additional lipid, soybean grain, soybean oil and cottonseed. The experimental period was 84 days, with four 21-day periods (14 days for diet adaptation and 7 for collection). Diets were offered ad libitum, twice daily, as total mixed ration. At the collecting period, samples of food and surpluses were weighed and collected for chemical analysis. Faeces samples were collected from rectum for estimation of faecal dry matter production, using indigestible neutral detergent fiber as indicator, and consequently for apparent digestibility calculations. Dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) intakes were similar between treatments. The ether extract intake was higher for soybean oil diet. The same behavior was observed for the total digestible nutrient (TDN) intake for this diet, since the previous diet showed higher TDN percentage. The digestibility coefficient for DM, CP, non-fibrous carbohydrate, and serum urea nitrogen were similar between diets. Different lipid sources in the diets for lactating water buffalo did not influence the DM intake and digestibility coefficient, when ether extract content was under 5%. However, the ether extract and fibrous fractions digestibility coefficients in diets with soybean grain and cottonseed were the lowest.

Características de carcaça e cortes comerciais de tourinhos Red Norte e Nelore terminados em confinamento

The objective of this study was to evaluate the characteristics of carcass and weight of the commercial meat cuts from carcass of Red Norte and Nellore young bulls finished in feedlot. Forty four animals - 22 Red Norte with initial average weight of 367±30 kg and 22 Nellore at initial average weight of 361±30 kg - were used. The animals received feed ad libitum with concentrate:roughage ratio of 50:50 during 112 days, from which 28 days were for adaptation. Red Norte and Nellore animals were slaughtered at 519 and 482 kg, respectively. The subcutaneous fat thickness (FT) and longissimus muscle area (LMA) were measured between 12th and 13th ribs. Higher carcass yield of the Nellore breed was observed (57.7 vs 54.7%). However, there was no difference for weight of hot and cold carcass between the groups. Red Norte animals showed greater LMA, and hindquarter and spare ribs with higher weight and yield, and forequarter with lower weight and yielding. The Red Norte genetic group showed higher weight for cap and rump and striploin, while Nellore showed higher weight for shoulder and flatround. Nellore animals had better carcass yield, which contributes to hot carcass weight. Nevertheless, the group Red Norte have higher hindquarter yield and more weight from cuts of highest commercial value.

Freezing, thawing and aging effects on beef tenderness from Bos indicus and Bos taurus cattle.

The objective of this study was to determine the effects of freezing prior to aging on the meat tenderness of young Nellore and Aberdeen Angus bulls. Samples of the longissimus thoracis muscle were submitted to two treatments: conventional aging and freezing (-20°C for 40 days) followed by thawing and aging periods. The meats were evaluated after 0, 7, 14 and 21 aging days (1°C). Freezing increased (P<0.05) purge, cooking loss and total exudate loss throughout aging. Nellore meats had greater total exudate loss and shorter sarcomere lengths (P<0.05). Freezing increased proteolysis during aging in the meats of both breeds, but reduced shear force was found (P<0.05) only in Aberdeen Angus meats and only at time zero. These results suggest that the meat tenderizing process by freezing prior to aging may contribute to meat tenderness in the first weeks of aging, but it is dependent on the animal breed.

VIABILIDADE ECONOMICA DA TERMINAÇÃO DE NOVILHOS NELORE E RED NORTE EM CONFINAMENTO NA REGIÃO DE LAVRAS-MG

Conduziu-se este trabalho, com o objetivo de verificar a viabilidade economica da terminacao em confinamento de novilhos Nelore e Red Norte na regiao de Lavras, MG. Foram utilizados 41 novilhos, nao castrados, de dois grupos geneticos, sendo: 19 Nelore e 22 Red Norte, com pesos vivos iniciais medios de 315 ±31 kg e 321 ±30 kg, respectivamente. O periodo experimental foi de 112 dias, divididos em quatro periodos de 28 dias. A viabilidade economica foi analisada utilizando o modelo de custo, considerando os custos operacionais, alternativos e de depreciacao. Todos os indicadores economicos gerados apresentaram resultados negativos. A atividade apresentou prejuizo de R

Qualidade da carne maturada de bovinos Red Norte e Nelore

6,88 e 19,74/arroba para os animais Red Norte e Nelore, respectivamente. Os resultados negativos obtidos nessas condicoes ocorreram porque o custo operacional efetivo foi maior que o preco de venda da arroba. Em um cenario com a aquisicao de animais a atividade de confinamento apresentou residuo proximo de zero para o grupo Red Norte. A pratica do confinamento nao apresentou viabilidade economica para a regiao de Lavras, MG, no ano de 2007.

Ácido linoléico conjugado e perfil de ácidos graxos no músculo e na capa de gordura de novilhos bubalinos alimentados com diferentes fontes de lipídios

The objective in this study was to evaluate meat quality of longissimus thoracisi muscle during ageing. Samples from 22 Nelore bovines and 22 Red Norte males at 24 months of age were collected at 24 hours post mortem, kept at 2oC and analyzed on days 1, 7, 14 and 21. The animals were finished in confinement (112 days) with corn silage (50%) and concentrate (50%) ad libitum. Values of final pH, cooking loss, moisture, protein, fat and ash were similar among samples of Nelore and Red Norte animals. The red level (a*) and the yellow intensity (b*) were similar among meats of the two genetic groups, however, luminosity (L*) was higher in samples of Red Norte animals. Ageing significantly affected luminosity, level of red and yellow, chroma, tone angle (H*) and subjective perception of the color (ΔE), thus, the most important changes in color occurred from 7 to 14 days. Shear force in the meat of Red Norte animals was approximately 0.9 kg lower than in Nelore animals. Ageing influenced shear force during maturation with a reduction of 1.09 kg, 0.21 kg and 0.56 kg in the periods from 1 to 7, from 7 to 14 and from 14 to 21 days, respectively. The myofibrillar fragmentation index was higher in the meat of Red Norte animals and in samples aged for 21 days. The meat of Red Norte animals showed more tenderness and luminosity. Ageing improves the tenderness of meat because it reduces shear force, however, it changes the color, whose most important changes take place from 7 to 14 days. The choice of the most appropriate ageing time for beef depends on which attribute will be considered.

Molecular Factors Underlying the Deposition of Intramuscular Fat and Collagen in Skeletal Muscle of Nellore and Angus Cattle.

The effect of different fat sources on fatty acid concentrations in the muscle and in the fat layer of water buffalo steers was studied. Twelve water buffalo steers weighting 306±8kg, fed without additional fat, soybean grain or soybean oil and confined during 84 days were used. The animals were slaughtered after 16-hours-fasting and the carcass was cooled at 5oC, for 24 hours. A section was extracted between 9th and 11th ribs from the right half carcass and this section was separated in bone, muscle and fat layer. In the last two fractions, the fatty acids, including conjugated linoleic acid (CLA), were quantified by gaseous chromatography. The soybean oil provided higher CLA concentrations in the steers muscle and fat layer. Moreover, the soybean oil inclusion promoted lower saturated fatty acids contents, mainly miristic and palmitic acids. There was also increase in CLA concentrations and decrease in miristic and palmitic acids contents in the fat layer of the animals fed soybean grain diet. However, these effects were more moderate than those observed for the diet with soybean oil.The effect of different fat sources on fatty acid concentrations in the muscle and in the fat layer of water buffalo steers was studied. Twelve water buffalo steers weighting 306±8kg, fed without additional fat, soybean grain or soybean oil and confined during 84 days were used. The animals were slaughtered after 16-hours-fasting and the carcass was cooled at 5oC, for 24 hours. A section was extracted between 9 and 11 ribs from the right half carcass and this section was separated in bone, muscle and fat layer. In the last two fractions, the fatty acids, including conjugated linoleic acid (CLA), were quantified by gaseous chromatography. The soybean oil provided higher CLA concentrations in the steers muscle and fat layer. Moreover, the soybean oil inclusion promoted lower saturated fatty acids contents, mainly miristic and palmitic acids. There was also increase in CLA concentrations and decrease in miristic and palmitic acids contents in the fat layer of the animals fed soybean grain diet. However, these effects were more moderate than those observed for the diet with soybean oil.