Three interrelated genes postulated to affect economically important traits related to growth and/or carcass quality of beef cattle were chosen to characterize and perform association analyses for this study. Melanocortin 1 receptor (MC1R), melanocortin 4 receptor (MC4R) and agouti related protein (AGRP) play an integral role in the appetite pathway and in fat deposition.<p> We genotyped 328 crossbred steers of various coat colours that were purchased at weaning and fed until slaughter for the previously published alleles ED, E+ and e. The E+ allele was present at five percent in this population and therefore was not included in further analysis. Black cattle of ED/ED or ED/e genotype had increased backfat (P<0.05) and required significantly fewer days (15-25) (P<0.01) on feed to reach a target fat level for slaughter compared to the red cattle. Red cattle of e/e genotype were found to have significantly larger longissimus dorsi (l. dorsi) area, shipping weight and hot carcass weight. Subsequent analysis revealed that the differences were comparable whether black versus red coat colour or MC1R genotype was used as the criteria for the group of cattle.<p> MC4R sequence was obtained from 20 random crossbred steers. In addition to several previously published polymorphisms, a novel Ser330Asn polymorphism was detected. A population of 382 crossbred Canadian steers and 985 crossbred American steers was genotyped for this Ser330Asn polymorphism. A minor allele frequency of 0.01 was observed in the Canadian and 0.02 in the American steer populations. No homozygous g.989AA cattle were detected. In the Canadian population, heterozygous steers had increased grade fat (P=0.036) and decreased lean meat yield (P=0.032). Similarly in the American population, steers of the g.989GA genotype had increased backfat (P=0.031) and less desirable yield grades (P=0.022,) but also lower ribeye area measurements (P=0.031). These results suggest that genotyping for the Ser330Asn polymorphism may lead to increased quality of carcasses either through lean meat production or backfat measurements, depending on the goal of the beef operation.<p> Sequence data obtained from 38 Bos taurus beef cattle, 4 Holsteins and 4 Bos indicus cattle revealed six polymorphisms in the AGRP gene. No polymorphisms that altered amino acids were detected in Bos taurus cattle. Genotyping of 382 crossbred beef steers was performed for two polymorphisms, an intronic deletion (g.439_440delTC) and a base pair substitution in exon 4 that did not alter an amino acid (g.715G>A). An ANOVA analysis, using PROC Mixed, was performed for both polymorphisms on several growth and carcass traits. No significant differences were observed.<p> Polymorphisms in MC1R and MC4R could be used as genetic tests which may be beneficial for beef producers in North America. The significant differences observed in this study in relation to cattle growth and fat deposition would represent savings for producers when used for sorting feedlot cattle or in selection of breeding cattle.

Three interrelated genes postulated to affect economically important traits related to growth and/or carcass quality of beef cattle were chosen to characterize and perform association analyses for this study. Melanocortin 1 receptor (MC1R), melanocortin 4 receptor (MC4R) and agouti related protein (AGRP) play an integral role in the appetite pathway and in fat deposition.<p> We genotyped 328 crossbred steers of various coat colours that were purchased at weaning and fed until slaughter for the previously published alleles ED, E+ and e. The E+ allele was present at five percent in this population and therefore was not included in further analysis. Black cattle of ED/ED or ED/e genotype had increased backfat (P<0.05) and required significantly fewer days (15-25) (P<0.01) on feed to reach a target fat level for slaughter compared to the red cattle. Red cattle of e/e genotype were found to have significantly larger longissimus dorsi (l. dorsi) area, shipping weight and hot carcass weight. Subsequent analysis revealed that the differences were comparable whether black versus red coat colour or MC1R genotype was used as the criteria for the group of cattle.<p> MC4R sequence was obtained from 20 random crossbred steers. In addition to several previously published polymorphisms, a novel Ser330Asn polymorphism was detected. A population of 382 crossbred Canadian steers and 985 crossbred American steers was genotyped for this Ser330Asn polymorphism. A minor allele frequency of 0.01 was observed in the Canadian and 0.02 in the American steer populations. No homozygous g.989AA cattle were detected. In the Canadian population, heterozygous steers had increased grade fat (P=0.036) and decreased lean meat yield (P=0.032). Similarly in the American population, steers of the g.989GA genotype had increased backfat (P=0.031) and less desirable yield grades (P=0.022,) but also lower ribeye area measurements (P=0.031). These results suggest that genotyping for the Ser330Asn polymorphism may lead to increased quality of carcasses either through lean meat production or backfat measurements, depending on the goal of the beef operation.<p> Sequence data obtained from 38 Bos taurus beef cattle, 4 Holsteins and 4 Bos indicus cattle revealed six polymorphisms in the AGRP gene. No polymorphisms that altered amino acids were detected in Bos taurus cattle. Genotyping of 382 crossbred beef steers was performed for two polymorphisms, an intronic deletion (g.439_440delTC) and a base pair substitution in exon 4 that did not alter an amino acid (g.715G>A). An ANOVA analysis, using PROC Mixed, was performed for both polymorphisms on several growth and carcass traits. No significant differences were observed.<p> Polymorphisms in MC1R and MC4R could be used as genetic tests which may be beneficial for beef producers in North America. The significant differences observed in this study in relation to cattle growth and fat deposition would represent savings for producers when used for sorting feedlot cattle or in selection of breeding cattle.

Master of Science / Department of Animal Sciences and Industry / Terry A. Houser / Two experiments were conducted to determine the effects of dried distillers grains with solubles (DDGS) on pork loin and fat quality. In the first experiment, 1,160 barrows (PIC) were used in a 70-d study to determine the influence of DDGS and glycerol on pork loin and fat quality attributes. Barrows were fed a corn-soybean meal based diet with the addition of selected levels of DDGS (0 or 20%) and glycerol (0, 2.5, or 5%) feed stuffs. Loins from the two heaviest pigs in each pen were removed for evaluation of pork loin and fat quality. Experiment two was a pilot study, in which eight non-pregnant sows were fed either 0 or 50% DDGS with a corn soybean meal based diet for 92-d. In the first experiment, there were no DDGS x glycerol interactions for purge loss %, instrumental color (L*a*b*), visual color, marbling score, drip loss %, visual color, pH, Warner-Bratzler shear force (WBSF), cook loss %, myofibrillar tenderness, juiciness, pork flavor intensity, connective tissue amount, and overall tenderness. There was a DDGS x glycerol interaction (P<0.03) for off-flavor intensity. Pigs fed diets with 20% DDGS had higher WBSF values, lower myofibrillar tenderness, lower overall tenderness scores, lower connective tissue scores, and had more off-flavors (P<0.05). Loin fatty acid analysis revealed an increase in palmitoleic, linoleic, and eicosadienoic acids (P<0.05) and iodine value (P<0.03) for pigs fed 20% DDGS. In the second experiment, there were no differences (P>0.64) in BW or backfat change for sows fed either 0 or 50% DDGS. No differences (P>0.23) in lipid oxidation from lean trimmings as measured by 2-thiobarbituric acid reactive substances (TBARS) assay were reported either initially or after 5 d of retail display for sows fed either 0 or 50% DDGS. As expected, lipid oxidation increased (P<0.003) as measured by TBARS assay for both treatments from d 1 to 5. Jowl fatty acid analysis revealed an increase in linoleic acid (P<0.01), total polyunsaturated fatty acids (P<0.01), and the ratio of polyunsaturated fatty acids to saturated fatty acids (P<0.03) for sows fed 50% DDGS.

Excess of fat deposition is a negative factor for poultry production, which affects feed efficiency and consequently the costs of meat production. The incorporation of genomic tools in poultry breeding programs may help to accelerate the selection for increased production efficiency. In this context, we genotyped approximately 2,000 42 days-old chickens from two different populations (Brazilian F2 Chicken Resource population and TT broiler Reference Population) using a high-density SNP array (600K, Affymetrix) to estimate genomic heritability of fatness-related traits, to identify genomic regions and positional candidate genes (PCGs) associated with these traits. We performed genome-wide association (GWAS) analysis using GenSel software (Bayesian approach) to identify 1 Mb genomic windows associated with abdominal fat, skin and carcass fat content traits. The search for PCGs were made within each genomic windows associated considering their Gene Ontology (GO) terms and also the literature information. We also integrated into this study NGS-SNPs data from both populations and selection signature regions identified in Brazilian F2 Chicken Resource population to refine the list of PCGs. The genomic heritability values for fatness-related traits were from moderate to high (greater than 0.30). We identified quantitative trait loci (QTL) for abdominal fat, skin and carcass fat content traits harboring several PCGs involved in biological processes of fat deposition. We identified several NGS-SNPs annotated in potential functional regions in our PCGs and some of those were predicted as deleterious and high impact mutations. Besides that, some genes overlapped with selection signature regions in Brazilian F2 Chicken Resource population. Important candidate genes for fat deposition were identified, providing new insights to achieve a better understanding of the genetic control of fat deposition in chickens. / O excesso de deposição de gordura é um fator negativo para a produção de aves, o que afeta a eficiência alimentar e consequentemente os custos da produção de carne. A incorporação das ferramentas genômicas em programas de melhoramento de aves pode ajudar a acelerar a seleção para aumentar a eficiência da produção. Neste contexto, genotipamos cerca de 2.000 aves de 42 dias de duas populações diferentes (população F2 experimental brasileira e população de corte referência TT) usando um chip de SNPs de alta densidade (600K, Affymetrix) para estimar a herdabilidade genômica de características relacionadas à deposição de gordura, para identificar regiões genômicas e genes candidatos posicionais (PCGs) associados a essas características. Realizamos análises de associação genômica ampla (GWAS) usando o programa GenSel (abordagem Bayesiana) para identificar janelas genômicas de 1 Mb associadas com características de gordura abdominal, pele e conteúdo de gordura na carcaça. A busca por PCGs foi feita dentro de cada janela genômica associada, considerando os Gene Ontology (GO) terms e também a informação da literatura. Integramos neste estudo NGS-SNPs identificados em animais parentais de ambas as populações, e além disso, regiões de assinaturas de seleção identificadas na população F2 experimental brasileira para refinar a lista de PCGs. Os valores de herdabilidade genômica para as características relacionadas à gordura foram de moderado a alto (maior que 0,30). Identificamos QTL para características de gordura abdominal, pele e conteúdo de gordura na carcaça contendo PCGs envolvidos em processos biológicos de deposição de gordura. Identificamos vários NGS-SNPs anotados em regiões potencialmente funcionais em nossos PCGs e alguns desses foram preditos como mutações deletérias e de alto impacto. Além disso, alguns genes se sobrepuseram com regiões de assinatura de seleção na população F2 experimental brasileira. Foram identificados importantes genes candidatos para a deposição de gordura, fornecendo novos insights para alcançar uma melhor compreensão do controle genético da deposição de gordura em frangos.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study was to evaluate the performance and carcass characteristics of cattle breed Aberdeen Angus steers of small and medium frame score slaughtered the same degree of completion of housing (average 6.39 mm). To 18 steers were used with age and weight of 298 days and 202.17 kg at entry into the confinement. The animals were confined for 158 days and slaughtered at average live weight of 430 days and 428.94 kg. The feed was composed of sorghum silage and concentrate in the ratio of 60:40 in the dry matter in the first 63 days and after 50:50 until slaughter. The frame was calculated using the formula F=-11, 548+0,4878*h*0,0289*ID+0,0000146*ID²+0,0000759*h*ID. Steers with medium frame score showed superiority in important aspects of marketing, as the initial weight (y=107.87+250.04B; P=.0002), final (y=308.14+32.07B; P=.0001), the empty body (y=255.07+30.74B; P<.0001) and hot carcass (y=153.91+21.09B; P<.0001) and cold (y=150.29+20.78B; P<.0001). Measures of muscle content as the Longissimus dorsi area in relation to cold carcass weight (ȳ=32.64-1.53; P=.0477) and empty body (ȳ=16.3-0.55B; P=.0419) were lower in of the carcass. Carcass conformation (P=.4660) Longissimus dorsi area in cm² (P=.6999),cushion thickness (P=.3578) were similar between the small and medium frame score. The commercial cuts, forequarter (ȳ=54.93+7.84B; P<.001), rib (ȳ=21.33+3.31B; P=.009) and back (ȳ=74.02+9.64B; P=.0003) in kg was higher in medium frame score. As a percentage cut back fell .18% with the incrase in frame score (ȳ=49-.18B P.0404). Weight tissue constituents of the carcass increased with the frame score of the steers, as on the percentage muscle tissue decreased by .57% (ȳ=61.63-.57B; P=.0410). The meat of Longissimus dorsi muscle of steers Aberdeen Angus of small and medium frame score showed intramuscular fat with a mean average of 10.11 points (P=.7034), red color with an average of 4.33 points (P=.3724), fine texture with a tendency to thin with an average 4.61 points (P=.3075) and the shear force with an average of 2.72 kg/cm² (P=.4004). Composition chemical of beef Longissimus dorsi muscle frame score steers Aberdeen Angus presented moisture with 72.27% (P=4355), crude protein of 19.34% (P=4150), lipid with 3.96% (P=9071), minerals with 4.43% (P=9842) and cholesterol to 50.25 mg/100g of meat (P=.2375). The small and medium frame score did not influence trhe fatty acids palmitic (P=.0790), stearic (P=.2455), oleic (P=.3046), linoleic (P=.9456), occurring change in the composition fatty acids myristic (y=1,85+0,12F; P=.043). The introduction of the frame score in studies of meat composition may be important in determining the frame score of steers with the nutritional features of the best meat. The medium frame score of Aberdeen Angus steers had higher head weight (y=9.35+.49B; P=.0212), feet (=5.38+.57B; P=.0059), tongue (y=.93+.05B; P=.0154), heart (y=1.45+.07B; P=.0183), inguinal adipose tissue (y=1.79+.21B; P=.0336) and adipose tissue is not part of the carcass plus to this in the meat (y=88.5+3.70B; P=.0086). Steers with small frame score were more (y=1.46-.08B; P=.0407) in the participation of the lungs in relation to empty body weight Aberdeeen Angus Steers. The small and medium frame score did not affect the participation of the rumen-reticulum, abomasums, omasum, intestines and contents of the gastrointestinal tract weight in relation to body weight an empty body weight. / O trabalho teve por objetivo avaliar o desempenho, as características da carcaça, da carne e os componentes não integrantes da carcaça de bovinos da raça Aberdeen Angus superjovens de biótipo pequeno e médio abatidos o mesmo grau de acabamento da carcaça (média de 6,39 mm). Foram utilizados 18 novilhos com idade e peso no ingresso no confinamento de 298 dias e 202,17kg. Os animais foram confinados durante 158 dias, abatidos com idade e peso vivo médio de 430 dias e 428,94kg. A alimentação foi composta por silagem de sorgo e concentrado, na relação volumoso:concentrado de 60:40 na matéria seca, nos primeiros 63 dias e após 50:50 até o abate. O biótipo foi calculado utilizando a fórmula B=-11,548+0,4878*h*0,0289*ID+0,0000146*ID²+0,0000759*h*ID. Os novilhos com biótipo médio apresentaram superioridade nos aspectos importantes de comercialização, como o peso inicial (y=107,87+250,04B; P=0,0002), final (y=308,14+32,07B; P=0,0001), de corpo vazio (y=255,07+30,74B; P<0,0001), de carcaça quente (y=153,91+21,09B; P<0,0001) e fria (y=150,29+20,78B; P<0,0001). As medidas de musculosidade da carcaça como a área de Longissimus dorsi em relação ao peso de carcaça fria (ȳ=32,64-1,53; P=0,0477) e de corpo vazio (ȳ=16,3-0,55B; 0,0419) foram menores nos novilhos de biótipo médio. A conformação da carcaça (P=0,4660), área de Longissimus dorsi em cm² (P=0,6999), espessura de coxão (P=0,3578) foram semelhantes entre os biótipos pequeno e médio. Os cortes comerciais, dianteiro (ȳ=54,93+7,84B; P<0,0001), costilhar (ȳ=21,33+3,31B; P=0,009) e traseiro (ȳ=74,02+9,64B; P=0,0003) em kg foi superior para o biótipo médio. Em percentagem o corte traseiro foi maior no biótipo pequeno (ȳ=49,00-0,18B; P=0,0404). Em peso os tecidos constituintes da carcaça aumentaram com o biótipo do novilho, à percentagem o tecido muscular apresentou queda de 0,57% (ȳ=61,63-0,57B; P=0,0410). A carne do músculo Longissimus dorsi de bovinos superjovens da raça Aberdeen Angus de biótipo pequeno e médio apresentou gordura intramuscular média com média de 10,11 pontos (P=0,7034), coloração vermelha com média de 4,33 pontos (P=0,3724), textura fina com tendência a muito fina com valor médio de 4,61 pontos (P=0,3075) e macia pelo força ao cisalhamento com média de 2,72 kgf/cm² (P=0,4009). O biótipo pequeno e médio apresentaram na carne do músculo Longissimus dorsi proporções de umidade com 72,27% (P=0,4355), de proteína bruta com 19,34% (P=0,4150), de lipídios com 3,96% (P=0,9071), de minerais com 4,43% (P=0,9842) e de colesterol com 50,25 mg/100g de carne (P=0,2375). O biótipo pequeno e médio não influenciaram nos ácidos graxos palmítico (P=0,0790), esteárico (P=0,2455), oléico (P=0,3046), linoléico (P=0,9456), ocorrendo alteração na composição do acido graxo mirístico (y=1,85+0,12B; P=0,043). A introdução do biótipo em estudos da composição da carne pode ser importante na determinação do biótipo de novilhos com melhores características nutraceuticas da carne. O biótipo médio dos novilhos Aberdeen Angus superjovens apresentaram maior peso de cabeça (y=9,35+0,49B; P=0,0212), das patas (y=5,38+0,57B; P=0,0059), da língua (y=0,93+0,05B; P=0,0154), do coração (y=1,45+0,07B; P=0,0183), do tecido adiposo inguinal (y=1,79+0,21B; P=0,0336) e do tecido adiposo não integrante da carcaça somado ao presente na carne (y=88,85+3,70B; P=0,0086). Os novilhos com biótipo pequeno apresentaram superioridade (y=1,46-0,08B; P=0,0407) na participação dos pulmões em relação ao peso de corpo vazio.Os novilhos Aberdeen Angus de biótipo pequeno e médio não alteraram a participação do rúmen-retículo, abomaso, omaso, intestinos e conteúdo do trato gastrointestinal em peso, em relação ao peso vivo e ao peso de corpo vazio.

Excess of fat deposition is a negative factor for poultry production, which affects feed efficiency and consequently the costs of meat production. The incorporation of genomic tools in poultry breeding programs may help to accelerate the selection for increased production efficiency. In this context, we genotyped approximately 2,000 42 days-old chickens from two different populations (Brazilian F2 Chicken Resource population and TT broiler Reference Population) using a high-density SNP array (600K, Affymetrix) to estimate genomic heritability of fatness-related traits, to identify genomic regions and positional candidate genes (PCGs) associated with these traits. We performed genome-wide association (GWAS) analysis using GenSel software (Bayesian approach) to identify 1 Mb genomic windows associated with abdominal fat, skin and carcass fat content traits. The search for PCGs were made within each genomic windows associated considering their Gene Ontology (GO) terms and also the literature information. We also integrated into this study NGS-SNPs data from both populations and selection signature regions identified in Brazilian F2 Chicken Resource population to refine the list of PCGs. The genomic heritability values for fatness-related traits were from moderate to high (greater than 0.30). We identified quantitative trait loci (QTL) for abdominal fat, skin and carcass fat content traits harboring several PCGs involved in biological processes of fat deposition. We identified several NGS-SNPs annotated in potential functional regions in our PCGs and some of those were predicted as deleterious and high impact mutations. Besides that, some genes overlapped with selection signature regions in Brazilian F2 Chicken Resource population. Important candidate genes for fat deposition were identified, providing new insights to achieve a better understanding of the genetic control of fat deposition in chickens. / O excesso de deposição de gordura é um fator negativo para a produção de aves, o que afeta a eficiência alimentar e consequentemente os custos da produção de carne. A incorporação das ferramentas genômicas em programas de melhoramento de aves pode ajudar a acelerar a seleção para aumentar a eficiência da produção. Neste contexto, genotipamos cerca de 2.000 aves de 42 dias de duas populações diferentes (população F2 experimental brasileira e população de corte referência TT) usando um chip de SNPs de alta densidade (600K, Affymetrix) para estimar a herdabilidade genômica de características relacionadas à deposição de gordura, para identificar regiões genômicas e genes candidatos posicionais (PCGs) associados a essas características. Realizamos análises de associação genômica ampla (GWAS) usando o programa GenSel (abordagem Bayesiana) para identificar janelas genômicas de 1 Mb associadas com características de gordura abdominal, pele e conteúdo de gordura na carcaça. A busca por PCGs foi feita dentro de cada janela genômica associada, considerando os Gene Ontology (GO) terms e também a informação da literatura. Integramos neste estudo NGS-SNPs identificados em animais parentais de ambas as populações, e além disso, regiões de assinaturas de seleção identificadas na população F2 experimental brasileira para refinar a lista de PCGs. Os valores de herdabilidade genômica para as características relacionadas à gordura foram de moderado a alto (maior que 0,30). Identificamos QTL para características de gordura abdominal, pele e conteúdo de gordura na carcaça contendo PCGs envolvidos em processos biológicos de deposição de gordura. Identificamos vários NGS-SNPs anotados em regiões potencialmente funcionais em nossos PCGs e alguns desses foram preditos como mutações deletérias e de alto impacto. Além disso, alguns genes se sobrepuseram com regiões de assinatura de seleção na população F2 experimental brasileira. Foram identificados importantes genes candidatos para a deposição de gordura, fornecendo novos insights para alcançar uma melhor compreensão do controle genético da deposição de gordura em frangos.