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This study aims to verify which of the oilseed meals will provide a higher milk production efficiency and milk nutrient profile in grazing cows to optimize the production system and improve milk nutrients for the benefit of nutrition and human health. A Latin square experiment was conducted with 12 cows for 84 days, fed Tanzania grass, and concentrated with cottonseed meal (CotM), sunflower meal (SunM), soybean meal (SoyM) and peanut meal (PeaM). SunM tended to have a higher production of 3.5% fat milk and higher milk urea nitrogen compared with the other treatments. SunM tended to have higher amount of fat in the milk compared with SoyM. PeaM tended to have lower fatty acids C13:0, C15:0 anteiso, C15:0 in milk compared with SunM. PeaM tended to have lower C16:0 and C17:0 iso compared with SoyM and CotM. PeaM had lower C18:1trans in comparison to the other meals. The addition of SoyM tended to have higher C18:1 cis15 compared with PeaM and tended to have lower thrombogenicity index compared with CotM and PeaM. Aiming at milk health in pasture production systems, SoyM presented the best nutritional quality of the lipid fraction. For productivity and fat yield, SunM had better results.

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Proteomics studies can be used to identify proteins that affect feed efficiency traits, related to cost and profitability of meat production. We used a proteomic approach based on two-dimensional electrophoresis (2D-PAGE) in combination with mass spectrometry (ESI-MS) to study liver samples of Nellore bulls divergently ranked according to residual feed intake (RFI). The study showed that 71 protein spots were expressed differentially (P < 0.05) among RFI groups and 47 were identified by ESI-MS. In RFI, efficient animals (low RFI) eat less than predictions, based on their weights and growth rate, while inefficient animals (high RFI) that eat more than predicted. Data from 18 animals (9 high vs. 9 low RFI) aged 24-26 months in feedlot finishing were used. Immediately after slaughter, liver samples were collected and protein extracts were separated. The gels of RFI groups were scanned and the images analyzed, whereby we found 279 and 215 liver protein spots in high and low RFI bulls, respectively. The proteins identified were related to the following biological functions: (I) oxygen transport and blood flow; (II) mitochondrial function and energy metabolism; (III) amino acid metabolism, ion transport, and cell survival. The study suggests hemoglobin subunit beta and heat shock protein 71 kDa and as molecular markers to study FE in Nellore cattle. Moreover, proteins such as 3-ketoacyl-CoA thiolase and glutamate dehydrogenase 1 were found in liver from high and low RFI animals, respectively. Such protein expression could be associated with changes in the oxidative capacity of RFI phenotypes.

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Objetivou-se avaliar os níveis de casca de banana seca ao sol na dieta de vacas F1 Holandês x Zebu sobre o perfil de ácidos graxos do leite e do queijo minas frescal. Os tratamentos foram constituídos de 0, 15, 30, 45 e 60% de substituição da silagem de sorgo pela casca de banana. O delineamento experimental foi em dois quadrados latinos 5 x 5 simultâneos. As amostras de leite e queijo foram analisadas quanto ao perfil de ácidos graxos por cromatografia gasosa. Observou-se efeito quadrático para o somatório de ácidos graxos poli-insaturados do leite, com valor máximo no nível de 23,54% de substituição. Houve efeito linear decrescente para os ácidos graxos C15:0 iso e C16:0 iso. Os ácidos graxos heneicosanoico, linoleico, linoleico conjugado e araquidônico apresentaram efeito quadrático. Não houve efeito das dietas sobre os ácidos graxos no queijo. A substituição de até 60% da silagem de sorgo por casca de banana na dieta de vacas em lactação pode ser alternativa para produção e processamento do leite, quando se considera a melhora no valor nutricional da fração lipídica do leite e o aumento dos teores de ácido linoleico conjugado.(AU)

This study aimed to evaluate the inclusion levels of dry banana peel in the sun in the diet of F1 Holstein x Zebu cows on the profile of fatty acids of milk and Minas fresh cheese. The diets were composed of 0, 15, 30, 45, and 60% replacement of sorghum silage by banana peel. The experimental design was Latin squares, simultaneous, 5 x 5. Samples of milk and cheese were analyzed for fatty acid composition by gas chromatography. Quadratic effect for the sum of milk polyunsaturated fatty acids, with the maximum level of 23,54% replacement. There was a decreasing linear effect for C15:0 iso fatty acids and C16: 0 iso. The heneicosanoic fatty acids, linoleic, conjugated linoleic and arachidonic presented quadratic effect. There was no effect of diets on fatty acids in cheese. Replacement of up to 60% of the sorghum silage of a banana peel in the diet of cows can be an alternative to milk production and processing when considering the improvement in the nutritional value of the milk lipid fraction and increase of the levels of conjugated linoleic acid.(AU)

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BACKGROUND: Despite the health concerns and nutritional importance of fatty acids, there is a relative paucity of studies in the literature that report genetic or genomic parameters, especially in the case of sheep populations. To investigate the genetic architecture of fatty acid composition of sheep, we conducted genome-wide association studies (GWAS) and estimated genomic heritabilities for fatty acid profile in Longissimus dorsi muscle of 216 male sheep. RESULTS: Genomic heritability estimates for fatty acid content ranged from 0.25 to 0.46, indicating that substantial genetic variation exists for the evaluated traits. Therefore, it is possible to alter fatty acid profiles through selection. Twenty-seven genomic regions of 10 adjacent SNPs associated with fatty acids composition were identified on chromosomes 1, 2, 3, 5, 8, 12, 14, 15, 16, 17, and 18, each explaining ≥0.30% of the additive genetic variance. Twenty-three genes supporting the understanding of genetic mechanisms of fat composition in sheep were identified in these regions, such as DGAT2, TRHDE, TPH2, ME1, C6, C7, UBE3D, PARP14, and MRPS30. CONCLUSIONS: Estimates of genomic heritabilities and elucidating important genomic regions can contribute to a better understanding of the genetic control of fatty acid deposition and improve the selection strategies to enhance meat quality and health attributes.

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Objetivou-se avaliar os níveis de casca de banana seca ao sol na dieta de vacas F1 Holandês x Zebu sobre o perfil de ácidos graxos do leite e do queijo minas frescal. Os tratamentos foram constituídos de 0, 15, 30, 45 e 60% de substituição da silagem de sorgo pela casca de banana. O delineamento experimental foi em dois quadrados latinos 5 x 5 simultâneos. As amostras de leite e queijo foram analisadas quanto ao perfil de ácidos graxos por cromatografia gasosa. Observou-se efeito quadrático para o somatório de ácidos graxos poli-insaturados do leite, com valor máximo no nível de 23,54% de substituição. Houve efeito linear decrescente para os ácidos graxos C15:0 iso e C16:0 iso. Os ácidos graxos heneicosanoico, linoleico, linoleico conjugado e araquidônico apresentaram efeito quadrático. Não houve efeito das dietas sobre os ácidos graxos no queijo. A substituição de até 60% da silagem de sorgo por casca de banana na dieta de vacas em lactação pode ser alternativa para produção e processamento do leite, quando se considera a melhora no valor nutricional da fração lipídica do leite e o aumento dos teores de ácido linoleico conjugado.(AU)

This study aimed to evaluate the inclusion levels of dry banana peel in the sun in the diet of F1 Holstein x Zebu cows on the profile of fatty acids of milk and Minas fresh cheese. The diets were composed of 0, 15, 30, 45, and 60% replacement of sorghum silage by banana peel. The experimental design was Latin squares, simultaneous, 5 x 5. Samples of milk and cheese were analyzed for fatty acid composition by gas chromatography. Quadratic effect for the sum of milk polyunsaturated fatty acids, with the maximum level of 23,54% replacement. There was a decreasing linear effect for C15:0 iso fatty acids and C16: 0 iso. The heneicosanoic fatty acids, linoleic, conjugated linoleic and arachidonic presented quadratic effect. There was no effect of diets on fatty acids in cheese. Replacement of up to 60% of the sorghum silage of a banana peel in the diet of cows can be an alternative to milk production and processing when considering the improvement in the nutritional value of the milk lipid fraction and increase of the levels of conjugated linoleic acid.(AU)

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The purpose of this study was to determine if Shc proteins influence the metabolic response to acute (7 days) feeding of a high-fat diet (HFD). To this end, whole animal energy expenditure (EE) and substrate oxidation were measured in the Shc knockout (ShcKO) and wild-type (WT) mice fed a control or HFD. The activities of enzymes of glycolysis, the citric acid cycle, electron transport chain (ETC), and ß-oxidation were also investigated in liver and skeletal muscle of ShcKO and WT animals. The study showed that ShcKO increases (P < .05) EE adjusted for either total body weight or lean mass. This change in EE could contribute to decreases in weight gain in ShcKO versus WT mice fed an HFD. Thus, our results indicate that Shc proteins should be considered as potential targets for developing interventions to mitigate weight gain on HFD by stimulating EE. Although decreased levels of Shc proteins influenced the activity of some enzymes in response to high-fat feeding (eg, increasing the activity of acyl-CoA dehydrogenase), it did not produce concerted changes in enzymes of glycolysis, citric acid cycle, or the ETC. The physiological significance of observed changes in select enzyme activities remains to be determined. SIGNIFICANCE OF THE STUDY: We report higher EE in ShcKO versus WT mice when consuming the HFD. Although decreased levels of Shc proteins influenced the activity of a central enzyme of ß-oxidation in response to high-fat feeding, it did not produce concerted changes in enzymes of glycolysis, citric acid cycle, or the ETC. Thus, an increase in EE in response to consumption of an HFD may be a mechanism that leads to decreased weight gain previously reported in ShcKO mice with long-term consumption of an HFD.

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Feed efficiency and carcass characteristics are late-measured traits. The detection of molecular markers associated with them can help breeding programs to select animals early in life, and to predict breeding values with high accuracy. The objective of this study was to identify polymorphisms in the functional and positional candidate gene NEUROD1 (neurogenic differentiation 1), and investigate their associations with production traits in reference families of Nelore cattle. A total of 585 steers were used, from 34 sires chosen to represent the variability of this breed. By sequencing 14 animals with extreme residual feed intake (RFI) values, seven single nucleotide polymorphisms (SNPs) in NEUROD1 were identified. The investigation of marker effects on the target traits RFI, backfat thickness (BFT), ribeye area (REA), average body weight (ABW), and metabolic body weight (MBW) was performed with a mixed model using the restricted maximum likelihood method. SNP1062, which changes cytosine for guanine, had no significant association with RFI or REA. However, we found an additive effect on ABW (P ≤ 0.05) and MBW (P ≤ 0.05), with an estimated allele substitution effect of -1.59 and -0.93 kg0.75, respectively. A dominant effect of this SNP for BFT was also found (P ≤ 0.010). Our results are the first that identify NEUROD1 as a candidate that affects BFT, ABW, and MBW. Once confirmed, the inclusion of this SNP in dense panels may improve the accuracy of genomic selection for these traits in Nelore beef cattle as this SNP is not currently represented on SNP chips.

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Mathematical models are important tools to estimate nutritional requirements and animal growth. Very few calf models generated from other countries with different feeding programs, environment and production systems have been evaluated. The objective of this paper is to evaluate two calf models: (i) the National Research Council (NRC) in 2001 and (ii) the updates published by Van Amburgh and Drackley in 2005 and inputted into Agricultural Modeling and Training Systems (AMTS, version 3.5.8). Data from 16 previous studies involving 51 diets for dairy calves under tropical conditions (n=485 calves, initial BW 37.5±4.35 kg and weaning weight of 62.0±10.16 kg) were used. The calves were fed with whole milk, milk replacer or fermented colostrum, plus starter (20.9±1.78% of CP). The accuracy of the average daily gain (ADG) prediction was evaluated by mean bias, mean square prediction error (MSPE), concordance correlation coefficient, bias correction factor (Cb), and regression between the observed and predicted values. The ADG observed from birth to weaning was 0.452±0.121 kg/day. Calves fed with whole milk had greater ADG compared with calves fed milk replacer (0.477 v. 0.379 kg/day) during the milk-feeding period. When all data were pooled (n=51 diets), predictions had a mean bias of -0.019 and 0.068 kg/day for energy-allowable gain using NRC and AMTS models, respectively. The regression equation between observed and predicted values obtained from energy of diets showed an intercept different from zero (P0.05) indicate that the AMTS growth model resulted in accurate predictions for calves fed with milk replacer. However, within these latter two approaches, the goodness of fit (R 2) was low, representing low precision. The weight gain estimated by the energy available from the diet was overestimated by 19 g/day when calculated by the NRC and underestimated by 68 g/day when calculated by AMTS. The reasons for this discrepancy need to be understood, for only then new models could be developed and parameterized to estimate animal performance in tropical conditions more accurately and precisely.

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Five hundred and seventy-five Nellore steers were evaluated for residual feed intake and residual feed intake and gain and their relationships between carcass, non-carcass and meat quality traits. RFI was measured by the difference between observed and predicted dry matter intake and RIG was obtained by the sum of -1*RFI and residual gain. Efficient and inefficient animals were classified adopting ±0.5 standard deviations from RFI and RIG mean. A mixed model was used including RFI or RIG and contemporary group as fixed effects, initial age as covariate and sire and experimental period as random effects, testing the significance of the regression slope for each evaluated trait. RIG was positively related to longissimus muscle area. Efficient-RFI animals had lower liver and internal fat proportions compared to inefficient-RFI animals. Efficient-RFI and efficient-RIG animals had 11.8% and 11.2% lower extracted intramuscular fat, compared to inefficient-RFI and inefficient-RIG animals, respectively. Efficient-RFI animals had tougher meat compared to inefficient-RFI animals.

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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 2×2 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 Δ9-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.

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