BackgroundSaturated fatty acids can be detrimental to human health and have received considerable attention in recent years. Several studies using taurine breeds showed the existence of genetic variability and thus the possibility of genetic improvement of the fatty acid profile in beef. This study identified the regions of the genome associated with saturated, mono- and polyunsaturated fatty acids, and n-6 to n-3 ratios in the Longissimus thoracis of Nellore finished in feedlot, using the single-step method.ResultsThe results showed that 115 windows explain more than 1 % of the additive genetic variance for the 22 studied fatty acids. Thirty-one genomic regions that explain more than 1 % of the additive genetic variance were observed for total saturated fatty acids, C12:0, C14:0, C16:0 and C18:0. Nineteen genomic regions, distributed in sixteen different chromosomes accounted for more than 1 % of the additive genetic variance for the monounsaturated fatty acids, such as the sum of monounsaturated fatty acids, C14:1 cis-9, C18:1 trans-11, C18:1 cis-9, and C18:1 trans-9. Forty genomic regions explained more than 1 % of the additive variance for the polyunsaturated fatty acids group, which are related to the total polyunsaturated fatty acids, C20:4 n-6, C18:2 cis-9 cis12 n-6, C18:3 n-3, C18:3 n-6, C22:6 n-3 and C20:3 n-6 cis-8 cis-11 cis-14. Twenty-one genomic regions accounted for more than 1 % of the genetic variance for the group of omega-3, omega-6 and the n-6:n-3 ratio.ConclusionsThe identification of such regions and the respective candidate genes, such as ELOVL5, ESSRG, PCYT1A and genes of the ABC group (ABC5, ABC6 and ABC10), should contribute to form a genetic basis of the fatty acid profile of Nellore (Bos indicus) beef, contributing to better selection of the traits associated with improving human health.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2511-y) contains supplementary material, which is available to authorized users.

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BackgroundFatty acid type in beef can be detrimental to human health and has received considerable attention in recent years. The aim of this study was to identify differentially expressed genes in longissimus thoracis muscle of 48 Nellore young bulls with extreme phenotypes for fatty acid composition of intramuscular fat by RNA-seq technique.ResultsDifferential expression analyses between animals with extreme phenotype for fatty acid composition showed a total of 13 differentially expressed genes for myristic (C14:0), 35 for palmitic (C16:0), 187 for stearic (C18:0), 371 for oleic (C18:1, cis-9), 24 for conjugated linoleic (C18:2 cis-9, trans11, CLA), 89 for linoleic (C18:2 cis-9,12 n6), and 110 genes for α-linolenic (C18:3 n3) fatty acids. For the respective sums of the individual fatty acids, 51 differentially expressed genes for saturated fatty acids (SFA), 336 for monounsaturated (MUFA), 131 for polyunsaturated (PUFA), 92 for PUFA/SFA ratio, 55 for ω3, 627 for ω6, and 22 for ω6/ω3 ratio were identified. Functional annotation analyses identified several genes associated with fatty acid metabolism, such as those involved in intra and extra-cellular transport of fatty acid synthesis precursors in intramuscular fat of longissimus thoracis muscle. Some of them must be highlighted, such as: ACSM3 and ACSS1 genes, which work as a precursor in fatty acid synthesis; DGAT2 gene that acts in the deposition of saturated fat in the adipose tissue; GPP and LPL genes that support the synthesis of insulin, stimulating both the glucose synthesis and the amino acids entry into the cells; and the BDH1 gene, which is responsible for the synthesis and degradation of ketone bodies used in the synthesis of ATP.ConclusionSeveral genes related to lipid metabolism and fatty acid composition were identified. These findings must contribute to the elucidation of the genetic basis to improve Nellore meat quality traits, with emphasis on human health. Additionally, it can also contribute to improve the knowledge of fatty acid biosynthesis and the selection of animals with better nutritional quality.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-3232-y) contains supplementary material, which is available to authorized users.

RESUMO -Este trabalho foi realizado para se avaliar o desempenho animal, as características da carcaça e a maciez da carne de 36 novilhos mestiços, apresentando, ao início do experimento, média de 14 meses de idade e aproximadamente 320 kg de peso vivo. Os animais foram confinados e receberam dietas com alto teor de concentrado: uma controle (CO), sem adição de lipídios; outra contendo 5% de sais de cálcio de ácidos graxos (AG); e outra com 21% de caroço de algodão (CA). A ingestão de matéria seca no tratamento AG foi menor que no CA, mas não diferiu da ingestão do CO. O ganho médio diário e a eficiência alimentar não apresentaram diferenças significativas entre os tratamentos. Os valores encontrados para a análise de uréia sangüínea foram significativamente maiores no tratamento CA em relação ao AG. O rendimento de carcaça, a área de olho de lombo, a espessura de gordura, as gorduras renal e pélvica, o peso do fígado, o pH e a temperatura não foram significativamente diferentes. Não houve diferença também para o índice de perda de água por cozimento e maciez, verificada pela força de cisalhamento nos diferentes tempos de maturação. Os sais de cálcio de ácidos graxos a 5% e o caroço de algodão a 21% podem ser empregados nas rações para confinamento, sem causarem alterações no desempenho animal ou nas características de carcaça.Palavras-chave: características de carcaça, caroço de algodão, confinamento, espessura de gordura, rendimento de carcaça, sais de cálcio de ácidos graxos Performance and Carcass Characteristics of Steers Fed Different Fat SourcesABSTRACT -The objective of this trial was to evaluate the animal performance, carcass characteristics and meat tenderness of 36 crossbred steers averaging 14 months old and 320 kg body weight. The animals were fed high concentrate-based diets: control -without additional fat (CO); diet with 5% calcium salt of fatty acids (AG); and diet with 21% whole cottonseed (CA). Dry matter intake of AG treatment was lower (P=0,05) than CA, that differ from CO diet. No significant differences of treatments on daily weight gain and feed efficiency were observed. Blood urea nitrogen was greater (P=0,01) for CA treatment than AG treatment. Carcass dressing, rib eye area, fat thickness, kidney and pelvic fat, liver weight, pH and temperature did not show significant difference. No difference on water loss during cooking and tenderness measured by shear force at different aging times was detected. Diets with 5% calcium salt of fatty acids or 21% whole cottonseed can be used for feedlot with no change on animal performance or carcass characteristics.

BackgroundThe aim of this study was to assess genome-wide autozygosity in a Nellore cattle population and to characterize ROH patterns and autozygosity islands that may have occurred due to selection within its lineages. It attempts also to compare estimates of inbreeding calculated from ROH (FROH), genomic relationship matrix (FGRM), and pedigree-based coefficient (FPED).ResultsThe average number of ROH per animal was 55.15 ± 13.01 with an average size of 3.24 Mb. The Nellore genome is composed mostly by a high number of shorter segments accounting for 78% of all ROH, although the proportion of the genome covered by them was relatively small. The genome autozygosity proportion indicates moderate to high inbreeding levels for classical standards, with an average value of 7.15% (178.70 Mb). The average of FPED and FROH, and their correlations (− 0.05 to 0.26) were low. Estimates of correlation between FGRM-FPED was zero, while the correlation (− 0.01 to − 0.07) between FGRM-FROH decreased as a function of ROH length, except for FROH > 8Mb (− 0.03). Overall, inbreeding coefficients were not high for the genotyped animals. Autozygosity islands were evident across the genome (n = 62) and their genomic location did not largely differ within lineages. Enriched terms (p < 0.01) associated with defense response to bacteria (GO:0042742), immune complex reaction (GO:0045647), pregnancy-associated glycoproteins genes (GO:0030163), and organism growth (GO:0040014) were described within the autozygotic islands.ConclusionsLow FPED-FROH correlation estimates indicate that FPED is not the most suitable method for capturing ancient inbreeding when the pedigree does not extend back many generations and FROH should be used instead. Enriched terms (p < 0.01) suggest a strong selection for immune response. Non-overlapping islands within the lineages greatly explain the mechanism underlying selection for functionally important traits in Nellore cattle.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-5060-8) contains supplementary material, which is available to authorized users.

The objective of this study was to estimate the genetic-quantitative relationships between the beef fatty acid profile with the carcass and meat traits of Nellore cattle. A total of 1826 bulls finished in feedlot conditions and slaughtered at 24 months of age on average were used. The following carcass and meat traits were analysed: subcutaneous fat thickness (BF), shear force (SF) and total intramuscular fat (IMF). The fatty acid (FA) profile of the Longissimus thoracis samples was determined. Twenty-five FAs (18 individuals and seven groups of FAs) were selected due to their importance for human health. The animals were genotyped with the BovineHD BeadChip and, after quality control for single nucleotide polymorphisms (SNPs), only 470,007 SNPs from 1556 samples remained. The model included the random genetic additive direct effect, the fixed effect of the contemporary group and the animal's slaughter age as a covariable. The (co)variances and genetic parameters were estimated using the REML method, considering an animal model (single-step GBLUP). A total of 25 multi-trait analyses, with four traits, were performed considering SF, BF and IMF plus each individual FA. The heritability estimates for individual saturated fatty acids (SFA) varied from 0.06 to 0.65, for monounsaturated fatty acids (MUFA) it varied from 0.02 to 0.14 and for polyunsaturated fatty acids (PUFA) it ranged from 0.05 to 0.68. The heritability estimates for Omega 3, Omega 6, SFA, MUFA and PUFA sum were low to moderate, varying from 0.09 to 0.20. The carcass and meat traits, SF (0.06) and IMF (0.07), had low heritability estimates, while BF (0.17) was moderate. The genetic correlation estimates between SFA sum, MUFA sum and PUFA sum with BF were 0.04, 0.64 and -0.41, respectively. The genetic correlation estimates between SFA sum, MUFA sum and PUFA sum with SF were 0.29, -0.06 and -0.04, respectively. The genetic correlation estimates between SFA sum, MUFA sum and PUFA sum with IMF were 0.24, 0.90 and -0.67, respectively. The selection to improve meat tenderness in Nellore cattle should not change the fatty acid composition in beef, so it is possible to improve this attribute without affecting the nutritional beef quality in zebu breeds. However, selection for increased deposition of subcutaneous fat thickness and especially the percentage of intramuscular fat should lead to changes in the fat composition, highlighting a genetic antagonism between meat nutritional value and acceptability by the consumer.

RESUMO -O objetivo deste trabalho foi avaliar o desempenho e características de carcaça de bovinos submetidos a dietas de alto concentrado contendo 15, 21 ou 27% da matéria seca em bagaço de cana-de-açúcar. Foram utilizados 24 novilhos Nelore, com peso médio em jejum de 279 kg e 24 meses de idade, confinados por um período de 98 dias. Não foram observados efeitos significativos para as características de ganho médio diário (média =1,461 kg) e eficiência alimentar. Foi observado efeito linear entre matéria seca ingerida e níveis de bagaço, com maior consumo nos tratamentos com menor percentagem de bagaço. Consistente com o comportamento do consumo, o peso do fígado também apresentou efeito linear, em função dos níveis de bagaço, sendo maior nos tratamentos com maior proporção de concentrado. As características peso de carcaça quente, gordura renal e pélvica, área de olho de lombo e espessura de gordura subcutânea não diferiram entre os tratamentos. Entretanto, observou-se comportamento linear do rendimento de carcaça, em função dos níveis de bagaço, sendo maior nos tratamentos com maior proporção de concentrado, consistente com o nível energético da ração. Os resultados indicam a viabilidade do uso de 15 ou 21% de bagaço como único volumoso, em dietas com elevada proporção de concentrado contendo milho, polpa de citrus e farelo de soja para novilhos Nelore em confinamento.Palavras-chave: bagaço de cana, bovinos, confinamento, dietas com alto concentrado, Nelore Levels of Sugarcane Bagasse in Diets with High Concentrate for Nellore Steers in FeedlotABSTRACT -The objective of this work was to evaluate the performance and carcass characteristics of cattle fed high concentrate diets containing 15, 21 or 27% of sugarcane bagasse in the dry matter. Twenty-four Nellore steers with 279 kg of shrunk body weight and 24 months of age, two per pen, were fed for 98 days. No significant effects were observed for average daily gain (mean =1.461 kg) and feed efficiency among the treatments. It was observed a linear effect between dry matter intake and levels of bagasse, with greater intake in treatments with lower proportion of bagasse. Consistent with intake, the liver weight presented linear association with bagasse levels, with higher weight in treatments with more concentrate. The hot carcass weight, kidney, pelvic, heart and inguinal fat, ribeye area and fat thickness were no different between treatments. However, it was observed a linear association between dressing percentage and bagasse levels, with higher percentage in treatments with more concentrate, consistent with the energy level of the diet. The results showed the viability of the use of 15 or 21% of sugarcane bagasse as the only roughage in high concentrate diets with corn, citrus pulp and soybean meal for Nellore steers in feedlot.

RESUMO -O objetivo deste trabalho foi estimar correlações entre medidas in vivo obtidas por ultra-som (US) e algumas características de carcaça. Foram utilizados 22 novilhos Nelore, com peso e idade médios de 279 kg e 24 meses, confinados por 98 dias e alimentados com dietas com elevada proporção de concentrado. O peso vivo, a área olho de lombo (AOLU) e a espessura de gordura subcutânea (EGSU) por US sobre o músculo "Longissimus dorsi" entre a 12ª e 13ª costelas, foram coletados a cada 28 dias. Foi utilizado um equipamento de US Piemedical Scanner 200 VET, com transdutor linear de 18 cm. Após o abate, foi tomado o peso de carcaça quente (PCQ) e da gordura renal, pélvica e inguinal (GRPI) e calculado o rendimento de carcaça (RC). Após 24 horas de resfriamento, foi medida a área de olho de lombo (AOLC) e a espessura de gordura subcutânea (EGSC) entre a 12ª e 13ª costelas, na carcaça. Tanto a AOLC quanto a EGSC foram subestimadas pelas medidas de US. Foram estimados coeficientes de correlação de Pearson para AOL e EGS medidas na carcaça e por US que foram 0,74 e 0,87, respectivamente. Foram obtidas também correlações de 0,27 entre RC e AOLU , 0,42 entre RC e AOLC, -0,30 entre RC e EGSU e -0,29 entre RC e EGSC. A GRPI apresentou uma correlação de 0,48 tanto com EGSC quanto com EGSU. Também foi estimada a correlação de Spearman entre AOLU e AOLC e EGSU e EGSC, obtendo-se valores de 0,89 e 0,77, respectivamente.Palavras-chave: área de olho de lombo, avaliação in vivo, bovinos, espessura de gordura subcutânea, Nelore, ultra-sonografia Correlations Among Carcass Characteristics Taken by Ultrasound and After Slaughter in Nellore Steers Fed High Concentrate DietsABSTRACT -The objective of this work was to estimate the correlations among measurements taken in vivo with ultrasound equipment with some carcass characteristics measured after slaughter. Twenty two Nellore steers, with average shrunk body weight of 279 kg and 24 months of age, were fed by 98 days with high concentrate diets. The shrunk body weight, the ribeye area (AOLU) and the fat thickness (EGSU) over the Longissimus dorsi muscle between 12ª and 13ª ribs, were measured at 28 days intervals. Real-time ultrasound equipment Piemedical Scanner 200 VET, with 18 cm linear array transducer was utilized. After the slaughter, the hot carcass weight (PCQ) and the kidney, pelvic and inguinal fat (GRPI) were weighted and the dressing percentage (RC) calculated. After 24 hours of cooling the ribeye area (AOLC) and the fat thickness (EGSC) were measured. Both the AOLC and the EGSC were underestimated by ultrasound measurements. The Pearson correlation coefficients for ribeye area and backfat thickness, measured in the carcass and with ultrasound, were 0,74 and 0,87, respectively. The coefficient between RC and AOLU was 0,27; 0,42 between RC and AOLC, -0,30 between RC and EGSU and -0,29 between RC and EGSC. The GRPI presented a 0,48 correlation coefficient with EGSC and EGSU. The Spearman correlation was estimated between AOLU and AOLC and EGSU and EGSC, and the values wer...