A velocidade de renovação das proteínas musculares define o crescimento muscular, e afetam a qualidade da carne, destacando-se a renovação de colágeno e taxa proteolítica que tem implicação no fenótipo de maciez. No entanto, existe pouca informação na literatura sobre mudanças no processo de remodelação de proteínas musculares em resposta à taxa de recuperação do ganho de peso, após um período de subnutrição em animais fisiologicamente maduros. Dessa forma, o uso de sequenciamento de RNA pode indicar mudanças no tecido muscular através de um perfil de expressão diferencial que explicam mudanças nos fenótipos associados ao crescimento muscular. Portanto, o objetivo deste estudo foi avaliar as mudanças no transcriptoma associado a fenótipos de carne de vacas adultas Nelore submetidas a diferentes taxas de recuperação de peso. Neste experimento foram utilizadas 28 vacas adultas de 5 a 16 anos, sendo que 23 animais, por apresentarem baixo escore corporal no inicio do experimento como resultado de perda de peso durante uma estação seca, foram aleatoriamente distribuídas em 3 grupos baseados em ganho diário de peso vivo: GB - Base (abatidos com baixo escore corporal, n=4); GL - Lento (0,6 kg/dia, n=9); GR - Rápido (1,2 kg/dia, n=10). Um quarto grupo (GM - Manutenção, n=5), foi formado de animais com alto escore corporal do início ao final do experimento. Os animais foram abatidos em quatro pontos definidos por dias (d) de confinamento (A1(0d) = GB; A2(51d) = GL e GR; A3(74d) = GR; A4(104d) = GL e GM), e as amostras do musculo Longissimus thoracis foram coletadas para obtenção do RNA total. Após a obtenção do mRNA e a preparação das bibliotecas de cDNA, o sequenciamento das amostras foi feito em um equipamento HiScanSQ. Vinte e quatro horas após o abate, foram determinados o pH e a cor instrumental (L*, a*, b*) medidos no músculo Longissimus thoracis. Dois bifes foram amostrados para a análise de força de cisalhamento às 24h e 21 dias. Na comparação entre fenótipos e genes, os contrastes utilizaram o grupo GB como referência. As análises estatísticas foram realizadas no programa R, usando ANOVA e teste de Tukey. Menores força de cisalhamento aos 21 dias (P<=0,05) foram encontradas para o grupo GL (A4) e GM (A4) comparadas ao GB. Valores de L*, a*, b* no músculo do GR (A3) também foram maiores em relação ao GB. Somente o valor de b* na gordura foi diferente (P<=0,05) em GR (A2 e A3) em relação ao GB. Foram identificados o total de 578 genes diferencialmente expressos (DE; FDR 5%) nos cinco contrastes avaliados. A análise funcional de genes DE entre contrastes identificou uma via KEEG para o grupo GL (\"Ribosome\") e cinco para o grupo GR (\"ECM receptor interaction\", \"Focal Adhesion\", \"Protein digestion and absorption\", \"PI3K-Akt signaling pathway\"). Para o enriquecimento GO, foram obtidas quatro categorias, sendo \"Semaphorin receptor activity\" para o grupo GL, enquanto \"Cellular response to amino acid stimulus\", \"Collagen trimer\" e \"Extracellular matrix structural constituent\" foram identificadas para GR. As vias em geral estão associadas a alterações no tecido conjuntivo do músculo. As diferenças encontradas entre fenótipos e genes indicam que as taxas de crescimento afetam de forma diferente os fenótipos associados à qualidade da carne. A realimentação em animais adultos, ao alterar o transcriptoma com possíveis impactos no tecido conjuntivo, parece mostrar um cenário de fibrose muscular no ganho rápido de peso, diferentemente do ganho lento, que mostrou ser uma alternativa para melhorar a qualidade da carne. Todavia, os impactos na estrutura muscular e proteica que possam explicar incremento em aspectos de textura da carne precisam ser determinados. / The speed of renewal of muscle proteins defines muscle growth, and affect meat quality, especially the renewal the of collagen turnover and proteolytic rate that has implication in the tenderness phenotype. There is little information in the literature about changes in the muscle protein remodeling process in response to the rate of recovery of weight gain after malnutrition in physiologically mature animals. In this way, the use of RNA sequencing may indicate changes in muscle tissue through a differential expression profile that explains changes in phenotypes associated with muscle growth. Therefore, the objective of this study was to evaluate changes in the transcriptome associated with meat phenotypes of Nellore adult cows submitted to different rates of weight recovery. In this experiment, 28 adult cows from 5 to 16 years old were used, being that twenty-three animals were distributed randomly in 3 groups based on daily gain of live weight, since they presented low body score at the beginning of the experiment as a result of weight loss during a dry season: GB - Base (slaughtered with low body score, n=4); GL - Slow (0.6kg/day, n=9); GR - High (1.2 kg/day, n=10). A fourth group (GM - Maintenance, n = 5) was formed from animals with high body score from the beginning to the end of the experiment. The animals were slaughtered at four points defined by confinement days(d) (A1(0d) = GB; A2(51d) = GL and GR; A3(74d) = GR; A4(104d) = GL and GM), and Longissimus thoracis muscle samples were collected to obtain the total RNA. After obtaining the mRNA and preparation of the libraries, the sequencing of the samples was done in a HiScanSQ equipment. Twenty-four hours after slaughter, the pH and instrumental color (L*, a*, b*) were determined in the Longissimus thoracis muscle. Two steaks were collected for shear force analysis at 24h and 21 days. In the comparison of the phenotypes and genes, contrasts were used the GB group as reference. Statistical analysis were performed in R software, using ANOVA and Tukey test. Lower shear forces at 21 days (P<=0.05) were found for the GL (A4) and GM (A4) groups compared to GB. Values of L*, a*, b* in the GR (A3) muscle were also higher in relation to GB. Only the value of b* in fat was different (P<=0.05) in GR (A2 and A3) in relation to GB. A total of 578 differentially expressed genes (DE; false discovery rate 5%) in the five contrasts evaluated. Functional analysis of DE genes between contrasts identified a KEEG pathway for the GL group (\"Ribosome\") and five for the GR group (\"ECM receptor interaction\", \"Focal Adhesion\", \"Protein digestion and absorption\", \"PI3K-Akt signaling pathway\"). For GO enrichment, four categories were obtained, being \"Semaphorin receptor activity\" for GL, while \"Cellular response to amino acid stimulus\", \"Collagen trimer\" and \"Extracellular matrix structural constituent\" were identified for GR. Pathways in general are associated with changes in connective tissue of muscle. Re-feeding in adult animals by altering the transcriptome with possible impacts on connective tissue, seems to show a scenario of muscle fibrosis in the fast gain of weight, unlike the slow gain, which proved to be an alternative to improve meat quality. However, the impacts on muscle and protein structure that may explain the increase in meat texture aspects need to be determined.

O objetivo doestudo foi estimar o crescimento dostecidos muscular e adiposo por ultrassonografia e verificar as possíveis diferenças entre grupos genéticos no crescimento e características produtivas de novilhas Angus e Brangus com idade inicial de oito meses, e novilhos Angus, Braford e Brangus com idade inicial de sete meses, recriados sobre pastagem. Para avaliação entre as raças de novilhas foramconsideradas as seguintes características: peso vivo (PV) área de olho de lombo (AOLUS), espessura de gordura subcutânea (EGSUS) e espessura de gordura na picanha (EGPUS), observação de cio e prenhez. As avaliaçõesdos novilhos foram realizadas utilizando-se as características, PV, AOLUS, EGSUS, EGPUS, peso de carcaça (PC), rendimento de carcaça (RC), peso de cortes primários (PCP) e rendimento de cortes primários (RCP). O peso vivo inicial (PVI) 224,37 kg das novilhas Angus não prenhas foi superior (p<0,05) a 219,30 kg das prenhas. A espessura de gordura subcutânea inicial (EGSIUS) em novilhas Angus prenhes 0,95 mm foi superior (p<0,05) a0,80 mm a das não prenhes. O PVI em novilhas Brangusnão prenhas 223,33 kg foi superior (p<0,05) a214,11 kg das prenhas. A espessura de gordura subcutânea final (EGSFUS) das novilhas Brangus prenhes 2,08 mm foi superior (p<0,05) a1,89 mm das não prenhes. Houve diferença (p<0,05) quanto a taxa de prenhez 88,22% das novilhas Angus e 73,91% das Brangus. O PVI 228,74 kg dos novilhos Angus foi superior (p<0,05) a195,92 kg dos Braford porém o PVI dos novilhos Brangus 220,26 kg não apresentou diferença entre médias. A área de olho de lombo inicial (AOLIUS) dos novilhos Angus 42,44 cm² foi superior (p<0,05) a 38,32 cm²dos Braford. Não houve diferença da AOLIUS40,69 cm² dos novilhos Brangus com os demais grupos genéticos. A EGSIUS 1,90 mm dos novilhos Angus e 2,20 mm dos Brangus não apresentaram diferença significativa, no entanto, as médias foram superiores (p<0,05) a 0,70 mm dos novilhos Braford. As características das carcaças dos novilhos coletadas ao abate não apresentaram diferença entre médias de peso e rendimento. Novilhas com maior espessura de gordura subcutânea final (EGSFUS) apresentaram maior número de animais com manifestação de 1º cio e prenhez. As variações ambientais ocorridas pelas estações do ano no sistema de produção, não influenciaram diferenças derendimento dos cortes primários das carcaças dos novilhos ao abate. / Theaim of this study was to estimate the growth of muscle and adipose tissues by ultrasound and check for any genetic differences between groups in growth and production characteristics of Angus and Brangus heifers with initial age of eight months and steers Angus, Brangus and Braford with initial age of seven months, recreated on pasture.For evaluation between breeds heifers were deemed the following characteristics, body weight (PV) rib eye area (AOLUS), backfat thickness (EGPUS) and fat thickness on the rump (EGPUS), observing estrus and pregnancy.The evaluation between breeds of steers was performed using the characteristics, PV, AOLUS, EGSUS, EGPUS, carcass weight (PC), carcass yield (RC), weight of primal cuts (PCP) and income primal cuts (RCP). Weight and characteristics evaluated by ultrasound showed no significant difference between breeds of Brangus and Angus heifers.In genetic group Angus initial body weight (PVI) of pregnant heifers 219.30 kg and not pregnant 224.37 kg was significantly different (p<0.05). The initial thickness of subcutaneous fat (EGSIUS) Angus heifers was significantly different (p <0.05) in animals pregnant 0.95 mm and non-pregnant 0.80 mm.In Brangus heifers the PVI was different (p<0.05) between heifers pregnant 214.11 kg and non-pregnant 223.33 kg. The final thickness of subcutaneous fat (EGSFUS) in Brangus heifers was significantly different (p<0.05) for pregnant animals 2.08 mm and non-pregnant1.89 mm.There were differences (p <0.05) as the pregnancy rate 82.22% of Angus heifers and 73.91% of Brangus. The PVI Angus steers 228.74 kg was higher (p<0.05) to the Braford steers 195.92 kg but Brangus steers 220.26 kg no differences between means of genetic groups.The initial ribeye area (AOLIUS) Angus steers 42.44 cm² was higher (p<0.05) of Braford steers 38.32 cm² with no difference of Brangus steers 40.69 cm² AOLIUS with other genetic groups.The EGSIUS Angus steers 1.90 mm and Brangus 2.20 mm showed no significant difference significantly, however the means were higher (p<0.05) of the steers Braford 0.70 mm.The characteristics of the carcasses of steers collected at slaughter showed no difference in mean weight and yield.Heifers with higher EGSUS showed higher participation in the number of animals with expression of 1st estrus and pregnancy. Environmental variations by the seasons in the production system did not influence differences in yield of the primary cuts of carcasses of steers for slaughter.

The renewal rate of stromal and myofibrillar proteins defines muscle growth, and can affect the quality of meat, by affecting collagen turnover and proteolytic rate. There is a lack of information on changes in the muscle protein remodeling process in response to the recovery weight gain rate observed during \"realimentation\" after undernutrition, which may be altered in older animals. Changes in muscle tissue during the recovery period may be indicated by the differential expression profile of genes after RNA sequencing. The objectives of this study were to evaluate transcriptome changes in the muscle of Nellore cull cows subjected to: 1) recovery weight gain under grazing conditions; and 2) recovery from undernutrition at different weight gain rates. In the first experiment, the animals were divided into two groups and subjected to one of two nutritional managements under grazing conditions: maintenance (maintenance of weight and high body condition score under grazing conditions) and recovery gain (recovery from low body condition score with moderate body weight gain of 0.6 kg/day under grazing conditions). In the second experiment, the animals were divided into three groups and subjected to one of three nutritional managements under feedlot conditions: control (slaughtered at low body condition score), moderate recovery gain (MG; 0.6 kg of daily live weight gain) during the dry season, and high recovery gain (HG; 1.2 kg of daily live weight gain) during the dry season. In both experiments, samples of longissimus dorsi muscle were collected after slaughter and immediately frozen until sequencing analysis could be performed. In the first experiment, genes related to inflammatory response, such as semaphorin 4A (SEMA4A), solute carrier family 11 member 1 (SLC11A1), ficolin-2 (FCN2), and placental growth factor (PGF), were expressed at higher levels during recovery gain. In the second experiment, osteonectin (SPARC) and collagen type IV subunits 1 (COL4A1) were expressed at higher levels in both recovery gain and connective tissue remodeling. For MG, structural myofibrillar proteins such as myosin IE (MYO1E), myosin, heavy chain 11 (MYH11), myogenin (MYOG), and actinin, alpha 4 (ACTN4) were identified. In the HG treatment, the B-cell CLL/lymphoma 9 (BCL9), peroxisome proliferator-activated receptor alpha (PPARA), diacylglycerol O-Acyltransferase 2 (DGAT2), and phosphatidylinositol 4-Kinase, catalytic, and beta (PI4KB) genes indicated more deposition of adipose tissue. In summary, we observed that muscular deposition during recovery weight gain involved the regulation of expression of several genes related to the extracellular matrix (ECM), corroborating the inflammatory and -like models observed in mature animals. Moreover, in the HG group, genes related to collagen synthesis and fat deposition were also found, indicating the important contribution of connective tissue during muscle growth. These results are important for understanding tissue development as a whole, and will assist in the progress of scientific knowledge on muscle remodeling during recovery weight gain and its influence on protein structures and intracellular routes. / A taxa de renovação do estroma e proteínas miofibrilares define o crescimento muscular, e pode afetar a qualidade da carne, afetando turnover de colágeno e taxa proteolítica. Há uma falta de informação sobre as mudanças no processo de remodelação de proteína muscular em resposta à taxa de recuperação do ganho de peso, observada durante a \"realimentação\" depois de subnutrição, o que pode ser alterado em animais mais velhos. Alterações no tecido muscular durante o período de recuperação pode ser indicada pelo perfil de expressão diferencial de genes, pela técnica de sequenciamento de RNA. Os objetivos deste trabalho foram avaliar as alterações do transcriptoma na musculatura de vacas de descarte Nelore submetidas a: 1) a recuperação do peso em condições de pastejo; e 2) a recuperação da desnutrição em diferentes taxas de ganho de pesos. No primeiro experimento, os animais foram divididos em: grupo de manutenção (manutenção de peso e de alta escore corporal); Recuperação do ganho (recuperação de baixo escore corporal com o ganho de peso corporal moderado em 0,6 kg / dia sob pastejo). No segundo experimento, os animais foram divididos em três grupos em confinamento: Controle (abatidos com baixo escore de condição corporal), ganho moderado (0,6 kg de ganho de peso vivo por dia) durante a estação seca e alta recuperação de ganho (1,2 kg de ganho de peso vivo por dia) durante a estação seca. Nos dois estudos, amostras do Longissimus dorsi foram coletadas após o abate e imediatamente congeladas até à análise de sequenciamento ser realizada. No primeiro experimento, os genes encontrados no tratamento de recuperação do ganho foram relacionados com a resposta inflamatória como: 4A semaphorin (SEMA4A), solute carrier family 11 member 1 (SLC11A1), Ficolin 2 (FCN2) e placental growth factor (PGF). No segundo experimento, o osteonectina (SPARC), colágeno tipo IV subunidades 1 (COL4A1) foram alguns dos genes mais expressos para ambas as taxas de ganho de recuperação de remodelação do tecido conjuntivo. Para ganho moderado, foram identificadas proteínas miofibrilares estruturais como: Myosin IE (MYO1E), Myosin, Heavy Chain 11 (MYH11), (MYOG) and actinin, alpha 4 (ACTN4). No tratamento de alta recuperação de ganho, genes como CLL de célula B / 9 linfoma (BCL9), peroxisome proliferator-activated receptor alpha (PPARA), Diacylglycerol O-Acyltransferase 2 (DGAT2) and Phosphatidylinositol 4-Kinase, Catalytic, Beta (PI4KB) indicam maior deposição de tecido adiposo. Em resumo, observou-se que a deposição muscular durante a recuperação do ganho de peso envolve a regulação da expressão de vários genes relacionados com a matriz extracelular (ECM), corroborando com modelos de inflamação e similar a fibrose observada em animais maduros. Além disso, no grupo HG, genes relacionados com a síntese de colágeno e a deposição de gordura, também foram encontrados, indicando contribuição do tecido conjuntivo durante o crescimento muscular. Estes resultados são importantes para a compreensão do desenvolvimento do tecido como um todo, e auxiliam no progresso do conhecimento científico sobre a remodelação muscular durante a recuperação do ganho de peso e sua influência sobre estruturas de proteínas e vias intracelulares.

O agonista beta-adrenérgico ractopamina (RAC) modifica a composição da carcaça suína por aumentar a massa muscular e reduzir a deposição de gordura. O objetivo neste estudo foi avaliar os efeitos do tempo de fornecimento de RAC sobre o desempenho, concentração de ureia plasmática (CUP), características de carcaça e expressão gênica dos receptores beta- adrenérgicos (beta-AR) e das isoformas da cadeia pesada de miosina (MyHC) em suínos em terminação. Oitenta suínos, machos castrados (PV inicial = 69,42 ± 1,24 kg), foram utilizados em um experimento em blocos completos casualizados com cinco tratamentos, oito repetições por tratamento e dois animais por unidade experimental (baia). Os tratamentos consistiram de rações sem RAC (controle) ou com 10 ppm de RAC fornecidas por 7, 14, 21 ou 28 dias préabate. O PV individual e o consumo de ração por baia foram obtidos para determinar o ganho diário de peso (GDP), o consumo diário de ração (CDR) e a conversão alimentar (CA). Amostras de sangue foram coletadas para determinação da CUP. No final do experimento, os animais (PV final = 102,46 ± 1,44 kg) foram abatidos e amostras de pelos e do músculo Longissimus dorsi coletadas. As carcaças foram avaliadas 24 horas post-mortem. As amostras de pelos foram utilizadas para detecção da mutação no gene do receptor de rianodina do tipo 1 (RYR1). A expressão gênica dos beta-AR (subtipos beta1 e beta2) e das isoformas MyHC (I, IIa, IIx/d e IIb) foi quantificada nas amostras de músculo. As análises estatísticas foram realizadas apenas com os animais homozigotos dominantes para a mutação no gene do RYR1. O aumento no período de fornecimento de RAC não afetou (P > 0,05) o PV final, o GDP e o CDR, porém resultou em melhora linear (P < 0,01) na CA. Melhoras (P < 0,05) nas médias semanais de GDP e CA foram observadas durante os primeiros 21 dias de fornecimento de RAC, no entanto, o crescimento animal declinou (P < 0,05) na 4ª semana de tratamento. A CUP apresentou efeito quadrático (P < 0,01) com o aumento na duração do fornecimento de RAC. Houve aumento linear (P <= 0,01) no peso da carcaça quente, na profundidade do músculo Longissimus dorsi, na área de olho de lombo e na relação carne:gordura com o aumento na duração do tratamento com RAC. Não foram detectados efeitos da RAC (P > 0,05) sobre a expressão gênica dos beta1-AR e das isoformas MyHC IIa e MyHC IIx/d, porém o aumento no período de fornecimento de RAC tendeu a reduzir linearmente (P = 0,08) a expressão gênica dos beta2-AR. Embora os níveis de RNAm da isoforma MyHC I tenham sido reduzidos linearmente (P < 0,01), a expressão gênica da isoforma MyHC IIb aumentou linearmente (P < 0,01) com o aumento na duração do tratamento com RAC. Portanto, as melhores respostas de desempenho e carcaça ocorreram quando a RAC foi fornecida por 21 e 28 dias, respectivamente. Além disso, o agonista alterou a expressão gênica das isoformas MyHC, e é possível que a ação da RAC esteja relacionada com a população de beta2-AR. / The beta-adrenergic agonist ractopamine (RAC) modifies the swine carcass composition by increasing muscle mass and decreasing fat deposition. The objective in this study was to evaluate the effects of RAC feeding duration on performance, plasma urea nitrogen (PUN) concentration, carcass traits, and gene expression of beta-adrenergic receptors (beta-AR) and myosin heavy chain (MyHC) isoforms in finishing pigs. Eighty barrows (initial BW = 69.42 ± 1.24 kg) were used in a randomized complete block design experiment with five treatments, eight replicates per treatment, and two animals per experimental unit (pen). The dietary treatments consisted of diets containing no RAC (control) or 10 ppm RAC fed for 7, 14, 21, or 28 days before slaughter. Individual pig BW and pen feed disappearance were obtained to determine average daily gain (ADG), average daily feed intake (ADFI), and feed to gain ratio (F:G). Blood samples were collected for determination of PUN concentrations. At the end of the experiment, pigs (final BW = 102.46 ± 1.44 kg) were slaughtered and hair and Longissimus dorsi muscle samples collected. The carcasses were evaluated 24 hours postmortem. Hair samples were used to detect the mutation of the ryanodine receptor type 1 (RYR1) gene. Gene expression of beta-AR (beta1- and beta2-subtypes) and MyHC isoforms (I, IIa, IIx/d, and IIb) was quantified in the muscle samples. Statistical analyses were performed using only the homozygous dominant pigs for the RYR1 gene mutation. Increasing RAC feeding period did not affect (P > 0.05) final BW, ADG, and ADFI, but resulted in a linear improvement (P < 0.01) in F:G. Average weekly improvements (P < 0.05) in ADG and F:G were observed during the first 21 days of RAC feeding, however, animal growth declined (P < 0.05) in the 4th week of treatment. The PUN concentrations showed a quadratic effect (P < 0.01) as RAC feeding duration increased. There were linear increases (P <= 0.01) in hot carcass weight, Longissimus dorsi muscle depth, loin eye area, and muscle to fat ratio as RAC treatment duration increased. No effects of RAC feeding (P > 0.05) were detected for beta1-AR and for isoforms of MyHC IIa and MyHC IIx/d gene expression, but increasing RAC feeding period tended to linearly decrease (P = 0.08) beta2-AR gene expression. Even though mRNA levels of MyHC I isoform decreased linearly (P < 0.01), gene expression of MyHC IIb isoform increased linearly (P < 0.01) as RAC treatment duration increased. Therefore, greater growth and carcass responses occurred when RAC was fed for 21 and 28 days, respectively. Furthermore, the agonist altered the MyHC gene expression and the RAC action may be related to the beta2-AR population.

Made available in DSpace on 2014-06-11T19:22:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-23Bitstream added on 2014-06-13T20:48:51Z : No. of bitstreams: 1 freitas_tm_me_jabo.pdf: 366299 bytes, checksum: 1bd4b439f962523f1de379bb7e0d79a9 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O presente estudo teve como objetivo a comparação do desempenho produtivo e do crescimento muscular (morfometria das fibras musculares e expressão gênica dos fatores de regulação miogênica) de três linhagens de tilápia-do-nilo (GIFT, ―Supreme‖ e Tailandesa), alimentadas com dieta comercial contendo ou não o hormônio 17α-metiltestosterona, durante a fase inicial, quando ocorre o processo de diferenciação sexual. O trabalho foi conduzido em esquema fatorial (2 dietas X 3 linhagens), constituído por seis tratamentos com quatro repetições de cada, por 29 dias. As larvas (com quatro dias pós eclosão) foram estocadas na densidade de 4 larvas.L-1 e receberam dieta comercial farelada, em seis arraçoamentos diários. Foram realizadas cinco avaliações biométricas durante o experimento para verificação dos resultados de desempenho. Além disso, foram calculadas as taxas de sobrevivência, de masculinização e a homogeneidade dos animais no final do experimento. Para a avaliação morfométrica das fibras musculares (n = 8 indivíduos por tratamento) foram realizadas amostragens aos 4, 19 e 33 dias pós-eclosão, para confecção das lâminas de tecido muscular. Mensurou-se o diâmetro e a área de 200 fibras musculares para cada amostra, que foram distribuídas nas seguintes classes de diâmetro (D): classe 10 (D ≤10μm), classe 20 (10< D ≤20 μm), classe 30 (20< D ≤30 μm), classe 40 (30< D ≤40μm) e classe 50 (D > 40 μm). As análises de expressão gênica da MyoD e Miogenina foram realizadas por PCR em tempo real, com uma amostragem aos 4 dpe e outra aos 33 dpe. A linhagem ―Supreme‖ apresentou melhores respostas de desempenho produtivo e de sobrevivência, e menores valores do coeficiente de variação. As taxas de masculinização em todas as linhagens estiveram acima de 97%. A masculinização, por meio da adição de 17α-metiltestosterona, interferiu... / This study aimed to compare the performance and muscle growth (muscle fiber morphometry and gene expression of myogenic regulatory factors) from three Nile tilapia strains (GIFT, Supreme and Thai), fed commercial diet with or without the hormone 17α-methyltestosterone (MT) during the initial phase, when does the process of sexual differentiation. The experiment was conducted in a factorial scheme (3x2), making up six treatments with four replicates each. The larvae (4 days post-hatching, dph) were stocked at 4 larvae.L-1 and were fed a commercial diet six times a day, during 29 days. Fish growth was evaluated along the experiment, as well as the survival rates, masculinization rates and homogeneity of the animals at the end (29 days). For the morphometric analysis of the muscle fibers (n = 8 per treatment), samples were taken at 4, 19 and 33 days post-hatching (dph) and transversal sections of the epiaxial muscle were obtained. The diameter (d) and the area of 200 muscle fibers were measured in each sample, and the diameters were classified as follow: class 10 = d ≤ 10 μm, class 20 = 10 < d ≤ 20 μm, class 30 = 20 < d ≤ 30 μm, class 40 = 30 < d ≤ 40 μm, and class 50 = d > 40μm. The analysis of gene expression of MyoD and Myogenin were performed by real time PCR (sampling at 4 and 33 dph). The Supreme strain showed better growth performance, survival rates, and size homogeneity. All strains displayed masculinization rates above 97%. The use of MT affected the productive performance of Nile tilapia larvae, and the effects were different among the strains. The proportion of males and females of the juveniles that did not receive MT suggests a certain dependence on the strain used, requiring further studies in this direction. The ―Supreme‖ strain performed better, characterized by hyperplasia and hypertrophy of the muscle fibers... (Complete abstract click electronic access below)

Submitted by Maike Costa (maiksebas@gmail.com) on 2017-02-17T12:43:01Z No. of bitstreams: 1 rquivo total.pdf: 1353702 bytes, checksum: 83db724c3c959a4e1d35f4040336484d (MD5) / Made available in DSpace on 2017-02-17T12:43:01Z (GMT). No. of bitstreams: 1 rquivo total.pdf: 1353702 bytes, checksum: 83db724c3c959a4e1d35f4040336484d (MD5) Previous issue date: 2016-11-28 / Most organisms have circadian rhythms with a periodicity of 24-hour that are generated by an endogenous mechanism, the molecular clock, which has the ability to synchronize biological functions with environmental signals. This mechanism has fundamental importance in the homeostasis of the tissues that are under its influence. Among the genes of the molecular clock machinery, the clock and bmal are positive regulators of clock mechanism and they present sigmoid expression profile in the skeletal muscle in zebrafish (Danio rerio). CLOCK and BMAL participate on the activation of the myogenic regulatory factors (MRFs - myoD, myog, myf5 and myf6), which are important in the development and differentiation of muscle cells. Despite this knowledge, the physiological importance of circadian rhythm in skeletal muscle of fish is not known. Therefore, the objective of the present study was to produce a zebrafish transgenic lineage that expresses bmal1a constitutively in the skeletal muscle to investigate the role of the molecular clock in the muscle. The transfer rate of the transgene to offspring, effect of transgenesis in the survival and fish growth, and expression of the bmal1a, clock1a and MRFs were investigated. The founding transgenic population (F0) was obtained after microinjection, and positive larvae were observed as specimens which presented green fluorescent heart. F1 was obtained from natural crossings between F0 and NT fish. Likewise, F2 was obtained from F1. F2 transgenic and NT were used in this study. The transgenic lineage was successfully generated with 50% transmission from the transgene to the offspring following a Mendelian model. The analysis of gene expression was made by qPCR. The survival (41,4±0% F2 and 44,3±6% NT) and growth (3.7±0.1 cm F2 and 3.8±0.2 cm NT) of F2 were not statistically different from NT fish. Among the genes, clock1a and myog presented statistically significant differences between the lineages with circadian profile in NT fish, suggesting that myog may be a clock controlled genes. The other genes (bmal1a, myf5, myf6, and myoD) presented constitutive expression. In general, it can be verified that the constitutive expression of bmal1a did not present change in the expression of the molecular clock, not affecting the homeostasis of the skeletal muscle, survival and growth. / A maioria dos organismos apresentam ritmos circadianos em torno de um período de 24 horas que são gerados por um mecanismo endógeno, o relógio molecular, que tem a capacidade de sincronizar-se com sinais ambientais. Este mecanismo tem fundamental importância na homeostase dos tecidos que estão sob sua influência. Dentre os genes que compõem a maquinaria do relógio molecular os genes clock e bmal são os reguladores positivos do mecanismo desse relógio e apresentam expressão com perfil sigmoide em tecido como o músculo do peixe-zebra (Danio rerio), participando da ativação de alguns fatores regulatórios miogênicos (MRFs – myoD, myog, myf5 e myf6), os quais possuem importância para o desenvolvimento e diferenciação do músculo. Apesar deste conhecimento, não se sabe a importância fisiológica do ritmo de expressão circadiana no músculo esquelético de peixes. Neste sentido, o objetivo desse estudo foi investigar a taxa de transferência do transgene para a prole; se a transgenia para o gene bmal1a no músculo esquelético interferiu na sobrevivência e crescimento dos peixes; e avaliar se a expressão dos genes bmal1a, clock1a e MRFs apresentaram diferenças na linhagem transgênica comparada à linhagem não-transgênica (NT). Os fundadores (F0) foram obtidos após a microinjeção do plasmídeo e as larvas positivas foram observadas com coração verde fluorescente. A F1 foi obtida a partir de cruzamentos entre peixes F0 e NT. Da mesma forma, F2 foi obtida a partir da F1, os quais foram utilizados no presente estudo. A análise da expressão gênica das linhagens aos 11 meses de idade foi realizada utilizando a técnica qPCR. A linhagem transgênica foi gerada com sucesso, transmitindo o transgene para a prole seguindo a herança mendeliana. A sobrevivência e crescimento da prole F2 não apresentaram diferenças entre as linhagens, sendo 41,4±0% para a linhagem transgênica e 44,3±6% NT até 30 dpf e 3.7±0.1 cm transgênicos e 3.8±0.2 cm para NT aos 11 meses de idade, respectivamente. Dentre os genes, o clock1a e o myog apresentaram diferenças estatisticamente significativas entre as linhagens com perfil circadiano em peixes NT, sugerindo que myog seja um gene controlado pelo relógio. Os demais genes apresentaram expressão constitutiva. De um modo geral, pode-se verificar que a expressão constitutiva do bmal1a não apresentou alteração na expressão do relógio molecular, desta forma, não afetou a homeostasia do organismo, a sobrevivência das larvas, bem como não afetou o crescimento.

O objetivo doestudo foi estimar o crescimento dostecidos muscular e adiposo por ultrassonografia e verificar as possíveis diferenças entre grupos genéticos no crescimento e características produtivas de novilhas Angus e Brangus com idade inicial de oito meses, e novilhos Angus, Braford e Brangus com idade inicial de sete meses, recriados sobre pastagem. Para avaliação entre as raças de novilhas foramconsideradas as seguintes características: peso vivo (PV) área de olho de lombo (AOLUS), espessura de gordura subcutânea (EGSUS) e espessura de gordura na picanha (EGPUS), observação de cio e prenhez. As avaliaçõesdos novilhos foram realizadas utilizando-se as características, PV, AOLUS, EGSUS, EGPUS, peso de carcaça (PC), rendimento de carcaça (RC), peso de cortes primários (PCP) e rendimento de cortes primários (RCP). O peso vivo inicial (PVI) 224,37 kg das novilhas Angus não prenhas foi superior (p<0,05) a 219,30 kg das prenhas. A espessura de gordura subcutânea inicial (EGSIUS) em novilhas Angus prenhes 0,95 mm foi superior (p<0,05) a0,80 mm a das não prenhes. O PVI em novilhas Brangusnão prenhas 223,33 kg foi superior (p<0,05) a214,11 kg das prenhas. A espessura de gordura subcutânea final (EGSFUS) das novilhas Brangus prenhes 2,08 mm foi superior (p<0,05) a1,89 mm das não prenhes. Houve diferença (p<0,05) quanto a taxa de prenhez 88,22% das novilhas Angus e 73,91% das Brangus. O PVI 228,74 kg dos novilhos Angus foi superior (p<0,05) a195,92 kg dos Braford porém o PVI dos novilhos Brangus 220,26 kg não apresentou diferença entre médias. A área de olho de lombo inicial (AOLIUS) dos novilhos Angus 42,44 cm² foi superior (p<0,05) a 38,32 cm²dos Braford. Não houve diferença da AOLIUS40,69 cm² dos novilhos Brangus com os demais grupos genéticos. A EGSIUS 1,90 mm dos novilhos Angus e 2,20 mm dos Brangus não apresentaram diferença significativa, no entanto, as médias foram superiores (p<0,05) a 0,70 mm dos novilhos Braford. As características das carcaças dos novilhos coletadas ao abate não apresentaram diferença entre médias de peso e rendimento. Novilhas com maior espessura de gordura subcutânea final (EGSFUS) apresentaram maior número de animais com manifestação de 1º cio e prenhez. As variações ambientais ocorridas pelas estações do ano no sistema de produção, não influenciaram diferenças derendimento dos cortes primários das carcaças dos novilhos ao abate. / Theaim of this study was to estimate the growth of muscle and adipose tissues by ultrasound and check for any genetic differences between groups in growth and production characteristics of Angus and Brangus heifers with initial age of eight months and steers Angus, Brangus and Braford with initial age of seven months, recreated on pasture.For evaluation between breeds heifers were deemed the following characteristics, body weight (PV) rib eye area (AOLUS), backfat thickness (EGPUS) and fat thickness on the rump (EGPUS), observing estrus and pregnancy.The evaluation between breeds of steers was performed using the characteristics, PV, AOLUS, EGSUS, EGPUS, carcass weight (PC), carcass yield (RC), weight of primal cuts (PCP) and income primal cuts (RCP). Weight and characteristics evaluated by ultrasound showed no significant difference between breeds of Brangus and Angus heifers.In genetic group Angus initial body weight (PVI) of pregnant heifers 219.30 kg and not pregnant 224.37 kg was significantly different (p<0.05). The initial thickness of subcutaneous fat (EGSIUS) Angus heifers was significantly different (p <0.05) in animals pregnant 0.95 mm and non-pregnant 0.80 mm.In Brangus heifers the PVI was different (p<0.05) between heifers pregnant 214.11 kg and non-pregnant 223.33 kg. The final thickness of subcutaneous fat (EGSFUS) in Brangus heifers was significantly different (p<0.05) for pregnant animals 2.08 mm and non-pregnant1.89 mm.There were differences (p <0.05) as the pregnancy rate 82.22% of Angus heifers and 73.91% of Brangus. The PVI Angus steers 228.74 kg was higher (p<0.05) to the Braford steers 195.92 kg but Brangus steers 220.26 kg no differences between means of genetic groups.The initial ribeye area (AOLIUS) Angus steers 42.44 cm² was higher (p<0.05) of Braford steers 38.32 cm² with no difference of Brangus steers 40.69 cm² AOLIUS with other genetic groups.The EGSIUS Angus steers 1.90 mm and Brangus 2.20 mm showed no significant difference significantly, however the means were higher (p<0.05) of the steers Braford 0.70 mm.The characteristics of the carcasses of steers collected at slaughter showed no difference in mean weight and yield.Heifers with higher EGSUS showed higher participation in the number of animals with expression of 1st estrus and pregnancy. Environmental variations by the seasons in the production system did not influence differences in yield of the primary cuts of carcasses of steers for slaughter.

O objetivo doestudo foi estimar o crescimento dostecidos muscular e adiposo por ultrassonografia e verificar as possíveis diferenças entre grupos genéticos no crescimento e características produtivas de novilhas Angus e Brangus com idade inicial de oito meses, e novilhos Angus, Braford e Brangus com idade inicial de sete meses, recriados sobre pastagem. Para avaliação entre as raças de novilhas foramconsideradas as seguintes características: peso vivo (PV) área de olho de lombo (AOLUS), espessura de gordura subcutânea (EGSUS) e espessura de gordura na picanha (EGPUS), observação de cio e prenhez. As avaliaçõesdos novilhos foram realizadas utilizando-se as características, PV, AOLUS, EGSUS, EGPUS, peso de carcaça (PC), rendimento de carcaça (RC), peso de cortes primários (PCP) e rendimento de cortes primários (RCP). O peso vivo inicial (PVI) 224,37 kg das novilhas Angus não prenhas foi superior (p<0,05) a 219,30 kg das prenhas. A espessura de gordura subcutânea inicial (EGSIUS) em novilhas Angus prenhes 0,95 mm foi superior (p<0,05) a0,80 mm a das não prenhes. O PVI em novilhas Brangusnão prenhas 223,33 kg foi superior (p<0,05) a214,11 kg das prenhas. A espessura de gordura subcutânea final (EGSFUS) das novilhas Brangus prenhes 2,08 mm foi superior (p<0,05) a1,89 mm das não prenhes. Houve diferença (p<0,05) quanto a taxa de prenhez 88,22% das novilhas Angus e 73,91% das Brangus. O PVI 228,74 kg dos novilhos Angus foi superior (p<0,05) a195,92 kg dos Braford porém o PVI dos novilhos Brangus 220,26 kg não apresentou diferença entre médias. A área de olho de lombo inicial (AOLIUS) dos novilhos Angus 42,44 cm² foi superior (p<0,05) a 38,32 cm²dos Braford. Não houve diferença da AOLIUS40,69 cm² dos novilhos Brangus com os demais grupos genéticos. A EGSIUS 1,90 mm dos novilhos Angus e 2,20 mm dos Brangus não apresentaram diferença significativa, no entanto, as médias foram superiores (p<0,05) a 0,70 mm dos novilhos Braford. As características das carcaças dos novilhos coletadas ao abate não apresentaram diferença entre médias de peso e rendimento. Novilhas com maior espessura de gordura subcutânea final (EGSFUS) apresentaram maior número de animais com manifestação de 1º cio e prenhez. As variações ambientais ocorridas pelas estações do ano no sistema de produção, não influenciaram diferenças derendimento dos cortes primários das carcaças dos novilhos ao abate. / Theaim of this study was to estimate the growth of muscle and adipose tissues by ultrasound and check for any genetic differences between groups in growth and production characteristics of Angus and Brangus heifers with initial age of eight months and steers Angus, Brangus and Braford with initial age of seven months, recreated on pasture.For evaluation between breeds heifers were deemed the following characteristics, body weight (PV) rib eye area (AOLUS), backfat thickness (EGPUS) and fat thickness on the rump (EGPUS), observing estrus and pregnancy.The evaluation between breeds of steers was performed using the characteristics, PV, AOLUS, EGSUS, EGPUS, carcass weight (PC), carcass yield (RC), weight of primal cuts (PCP) and income primal cuts (RCP). Weight and characteristics evaluated by ultrasound showed no significant difference between breeds of Brangus and Angus heifers.In genetic group Angus initial body weight (PVI) of pregnant heifers 219.30 kg and not pregnant 224.37 kg was significantly different (p<0.05). The initial thickness of subcutaneous fat (EGSIUS) Angus heifers was significantly different (p <0.05) in animals pregnant 0.95 mm and non-pregnant 0.80 mm.In Brangus heifers the PVI was different (p<0.05) between heifers pregnant 214.11 kg and non-pregnant 223.33 kg. The final thickness of subcutaneous fat (EGSFUS) in Brangus heifers was significantly different (p<0.05) for pregnant animals 2.08 mm and non-pregnant1.89 mm.There were differences (p <0.05) as the pregnancy rate 82.22% of Angus heifers and 73.91% of Brangus. The PVI Angus steers 228.74 kg was higher (p<0.05) to the Braford steers 195.92 kg but Brangus steers 220.26 kg no differences between means of genetic groups.The initial ribeye area (AOLIUS) Angus steers 42.44 cm² was higher (p<0.05) of Braford steers 38.32 cm² with no difference of Brangus steers 40.69 cm² AOLIUS with other genetic groups.The EGSIUS Angus steers 1.90 mm and Brangus 2.20 mm showed no significant difference significantly, however the means were higher (p<0.05) of the steers Braford 0.70 mm.The characteristics of the carcasses of steers collected at slaughter showed no difference in mean weight and yield.Heifers with higher EGSUS showed higher participation in the number of animals with expression of 1st estrus and pregnancy. Environmental variations by the seasons in the production system did not influence differences in yield of the primary cuts of carcasses of steers for slaughter.

Functional adaptations in human skeletal muscle following a period of resistance exercise are the result of regular activation of cellular signaling pathways that elevate muscle protein synthesis. It has been reported that the addition of whole body vibration (WBV) to a resistance exercise program enhances performance. Such improvements in muscle function may be the result of increased activation of cellular signaling pathways associated with muscle growth. Purpose: We have investigated whether an acute bout of resistance exercise in combination with WBV results in a greater activation of the mTOR signaling pathway compared to resistance exercise alone. Methods: Eight untrained college-age males (23 ± 2 yrs, 179 ± 1 cm, 75.0 ± 2.5 kg, and 12.6 ± 1.8% body fat) performed unilateral leg press exercises with (Vbx) and without (RT) vibration. Muscle samples were obtained from the vastus lateralis muscle pre-exercise (baseline) and one-hour following the bout of resistance exercise. Muscle tissue samples were analyzed for phosphorylated levels of mTOR, p70S6K, and 4E-BP1 proteins. Results: One-hour following the resistance exercise bout there were no differences between phosphorylated levels of mTOR or 4E-BP1 in Vbx or RT (p > 0.05). Levels of phosphorylated p70S6K were increased at the one-hour post-exercise time-point in both Vbx (baseline: 504 ± 286 OD; post: 5039 ± 2351 OD, p < 0.05) and RT (baseline: 356 ± 131 OD; post: 5430 ± 1218 OD, p < 0.05); however, there was no difference in protein phosphorylation levels between conditions (p > 0.05). Conclusion: Vibration does not augment acute activation of the mTOR signaling pathway in human skeletal muscle suggesting that performance benefits resulting from combining resistance exercise and vibration may not be the result of an enhanced cellular growth response.

In the present study, muscle growth and flesh quality have been investigated from both commercially farmed Atlantic halibut (Hippoglossus hippoglossus) (Aga marine AS, Norway)and halibut obtained from small-scale trials at Mørkvedbukta Research Station (Bodø University College, Norway). Morphometric techniques have been utilized to investigate fast muscle growth in halibut ranging from circa 2 g to 100 kg, and it was established that fast muscle fibre recruitment ceases when the fish attain approximately 81 and 177 cm, in the case of males and females, respectively. Different muscle fibre types were distinguished using histochemical (myosin ATPase and succinic dehydrogenase) and immunohistochemical (S-58, an antibody against slow muscle myosin) staining techniques. Females recruit twice as many fast muscle fibres compared to males, which allows them to reach a larger final size. Furthermore, the seasonal growth patterns during a one year production cycle in commercial farmed halibut revealed a winter depression in growth leading to loss of biomass, which was attributed to the maturation of males. Commercial farmed fish of equal size (~1.5 kg) showed sexual dimorphism of fast muscle fibre number, caused by a significantly higher rate of fast muscle fibre recruitment in females. During the winter season fast muscle fibres shrunk significantly, especially in male fish, as a consequence of loss of appetite, low water temperatures and sexual maturation. None of the female fish matured during the trial. Flesh quality of halibut deteriorated during winter and spring, since it had a softer appearance and significantly lower myotomal protein content, particularly in males. Cathepsin activity was measured using spectroscopy and showed a strong negative correlation to protein content, displaying a seasonal variation. The proteolytic depletion of fast muscle proteins affected the water holding capacity of the muscle (determined by centrifugation), which showed concomitant changes with the increase in cathepsin activity and drop in protein content. Despite the soft appearance, the firmness (shear force) of the flesh increased during the winter. The hydroxylysyl pyridinoline cross-link content of the collagen matrix, determined by HPLC, showed a strong correlation to the fillet texture. The increased firmness during the winter, a period of little (female) or negative growth (males), was probably due to an increased cross-linking of the collagen compartment. Partial sequences of IGF-I and IGF-II were cloned from fast muscle of Atlantic halibut, and their relative gene expression levels were determined along with those of cathepsin B, cathepsin D and IGF-IRa in male halibut using qPCR during a fasting and refeeding trial. Transcript levels of cathepsin B and to some extent cathepsin D were significantly higher during fasting than refeeding, suggesting an increased enzyme production during periods of food deprivation. A temporary increase in IGF-I transcripts was observed after 7 days refeeding suggesting that this growth factor is involved in muscle growth control. Both IGF- IRa and IGF-II were down-regulated during refeeding.