Testicular shape and andrological aspects of young Nellore bulls under extensive farming

Aiming to determine the relationship between the frequency of testicular shape and the andrological aspects in young Nellore bulls, 18,676 animals were assessed. All andrological examinations were performed between the years 2000 and 2008. Animals were classified as able for breeding, able for breeding in natural mating system, unable for breeding and discarded. The testicular shape was classified as long, fairly long, oval-long, spherical-oval, and spherical. The analysis of Pearson correlations was performed for testicular shape with scrotal circumference, testicular volume, progressive motility, sperm vigor, major defects, minor defects and total defects. Testicles with oval shape prevailed (99.61%). It was obseved that 76.34; 66.34; 64.34; 58.33 and 50.00% of the animals were classified as sound for breeding for shapes long, fairly long, oval-long, spherical-oval, and spherical, respectively. Correlations between testicular shape with scrotal circumference, testicular volume, progressive motility, sperm vigor, major, minor and total defects were 0.26; 0.08; 0.00; 0.11; -0.02; 0.02 and -0.01, respectively. Testicular shape had no influence upon the andrological examination results. Testicles of long shape were prevalent within the population

Metabolic profile and body weight of piglets fed with different levels of phosphorus in distinct thermal environments

O objetivo deste trabalho foi avaliar o efeito de dietas com diferentes concentrações de fósforo disponível sobre o perfil metabólico e o peso corporal de leitões em fase inicial de crescimento, mantidos em ambientes térmicos distintos. Foram utilizados 120 leitões machos castrados, de linhagem comercial e com peso corporal médio de 15 kg. Os tratamentos consistiram de dietas com 0,107, 0,214, 0,321, 0,428 e 0,535% de fósforo disponível, e de dois ambientes: termoneutro e quente. O peso corporal foi determinado no início e no final da fase experimental, e amostras de sangue foram coletadas para a medição de eletrólitos, albumina, proteína total, substâncias nitrogenadas, fosfatase alcalina total e óssea, hormônios tireoidianos, glicose e lactato. Tanto as dietas quanto os ambientes produziram efeito sobre o ganho de peso corporal e sobre os valores de sódio, potássio, cálcio total, magnésio, fósforo, fosfatase alcalina total e óssea, T4 livre e lactato. O aumento nos teores de fósforo na dieta tem efeito positivo sobre o peso corporal, nos ambientes estudados, mas desequilibra as relações sanguíneas cálcio:fósforo. O estresse por calor diminui as concentrações de glicose, fosfatase alcalina total e T4 livre no sangue, e aumenta as de lactato. Parâmetros bioquímicos sanguíneos retratam o estado metabólico dos animais e podem ser usados para avaliação do balanço nutricional e para detecção precoce de alterações metabólicas.The objective of this work was to evaluate the effect of diets with different available phosphorus contents on metabolic profile and on body weight of piglets at baseline, maintained in distinct thermal environments. One hundred and twenty barrow piglets from commercial strain and with an average body weight of 15 kg were used. The treatments consisted of diets with 0.107, 0.214, 0.321, 0.428, and 0.535% available phosphorus, and of two environments: thermoneutral and warm. Body weight was determined at the beginning and at the end of the experimental period, and blood samples were taken for measuring electrolytes, albumin, total protein, nitrogenous substances, total and bone alkaline phosphatase, thyroid hormones, glucose, and lactate. Both diets and environments had effect on body weight gain and on the values of sodium, potassium, total calcium, magnesium, phosphorus, total and bone alkaline phosphatase, free T4, and lactate. The increase in phosphorus contents in the diet has a positive effect on body weight in the studied environments, but it unbalances blood calcium:phosphorus relations. Heat stress decreases the levels of glucose, total alkaline phosphatase, and free T4 in the blood, and increases those of lactate. Blood biochemical parameters reflect the metabolic state of the animals and can be used to evaluate nutritional balance and for early detection of metabolic alterations

Toll-Like Receptor 6 differential expression in two pig genetic groups vaccinated against Mycoplasma hyopneumoniae

<p>Abstract</p> <p>Background</p> <p><it>Mycoplasma hyopneumoniae</it> is the etiologic agent of enzootic pneumonia, which causes important economic losses to swine industry. The Toll-like receptors (TLRs) are pattern-recognition receptors which detect microbial presence and initiate the innate as well as the adaptative immune defense. Toll-like receptor 6 is a type I transmembrane protein that recognizes bacterial components. The aim of this study was to compare mRNA expression pattern of TLR6 gene in two genetically distinct groups of pigs vaccinated against <it>Mycoplasma hyopneumoniae.</it></p> <p>Methods</p> <p>For each genetic group, peripheral blood was collected just before and 10 days after vaccination from 10 Naturalized Brazilian Piau breed and 10 Commercial White Line serum-negative female piglets. RNA was extracted from peripheral blood mononuclear cells (PBMCs), reverse transcripted and the qRT-PCR performed using SYBR green fluorescence system, using GAPDH gene as endogenous control. Analyses were performed by UNIVARIATE (Shapiro-Wilk test) and MIXED procedures of SAS software (version 9.0).</p> <p>Results</p> <p>It was observed significant interaction between breed and vaccination, being the TLR6 mRNA expression higher in the Commercial White line than in the Piau breed after vaccination. Furthermore, there was differential expression before and after vaccination in the Commercial White line.</p> <p>Conclusions</p> <p>Analysis of in TLR6 gene expression showed difference between the two distinct genetic groups, however, other TLRs gene expression must be evaluated for a better understanding of innate resistance in the pig concerning <it>Mycoplasma hyopneumoniae</it> infection.</p

Multi-Trait GWAS and new candidate genes annotation for growth curve parameters in Brahman cattle

Understanding the genetic architecture of beef cattle growth cannot be limited simply to the genome-wide association study (GWAS) for body weight at any specific ages, but should be extended to a more general purpose by considering the whole growth trajectory over time using a growth curve approach. For such an approach, the parameters that are used to describe growth curves were treated as phenotypes under a GWAS model. Data from 1,255 Brahman cattle that were weighed at birth, 6, 12, 15, 18, and 24 months of age were analyzed. Parameter estimates, such as mature weight (A) and maturity rate (K) from nonlinear models are utilized as substitutes for the original body weights for the GWAS analysis. We chose the best nonlinear model to describe the weight-age data, and the estimated parameters were used as phenotypes in a multi-trait GWAS. Our aims were to identify and characterize associated SNP markers to indicate SNP-derived candidate genes and annotate their function as related to growth processes in beef cattle. The Brody model presented the best goodness of fit, and the heritability values for the parameter estimates for mature weight (A) and maturity rate (K) were 0.23 and 0.32, respectively, proving that these traits can be a feasible alternative when the objective is to change the shape of growth curves within genetic improvement programs. The genetic correlation between A and K was -0.84, indicating that animals with lower mature body weights reached that weight at younger ages. One hundred and sixty seven (167) and two hundred and sixty two (262) significant SNPs were associated with A and K, respectively. The annotated genes closest to the most significant SNPs for A had direct biological functions related to muscle development (RAB28), myogenic induction (BTG1), fetal growth (IL2), and body weights (APEX2); K genes were functionally associated with body weight, body height, average daily gain (TMEM18), and skeletal muscle development (SMN1). Candidate genes emerging from this GWAS may inform the search for causative mutations that could underpin genomic breeding for improved growth rates

Independent component regression applied to genomic selection for carcass traits in pigs

O objetivo deste trabalho foi avaliar a eficiência do método de regressão via componentes independentes (ICR) na estimação de valores genéticos genômicos e dos efeitos de marcadores SNP para características de carcaça de uma população F2 de suínos (Piau x linhagem comercial). Os métodos foram avaliados por meio da concordância entre os valores genéticos preditos e os fenótipos corrigidos, observados por validação cruzada, e também foram comparados com outros métodos geralmente utilizados para os mesmos propósitos, tais como RR‑BLUP, PCR e PLS. Os métodos ICR e PCR apresentam resultados similares, mas o método ICR apresenta maiores valores de acurácia.The objective of this work was to evaluate the efficiency of the independent component regression (ICR) method for the estimation of genomic values and of SNP marker effects for carcass traits in a F2 pig population (Piau x commercial line). The methods were evaluated by the agreement between the genetic predicted values and the corrected phenotypes observed by cross‑validation, and they were also compared with other methods generally used for the same purposes, such as RR‑BLUP, PCR, and PLS. The ICR and PCR methods show similar results, but ICR has the highest accuracy prediction values

Perfil eletrolítico e peso corporal em suínos submetidos a dietas com diferentes teores de fósforo

The objective of this work was to evaluate the effect of diets containing different levels of phosphorus on blood electrolytic profile and on body weight gain in pigs. Sixty hybrid pigs were used, all barrows, with initial body weight of 61.07 ± 0.86 kg and about 110 days old. The animals were distributed in a randomized block design, in 5 treatments, with 12 replicates each. The treatments consisted of diets containing 0.135, 0.200, 0.265, 0.330 and 0.395% available phosphorus. At the beginning and at the end of the experiment, body weight was determined and blood samples were collected, in the animals without fasting, to measure sodium, potassium, chloride, total magnesium, phosphorus and ionized calcium. A quadratic response in body weight was observed, according to treatments, and for serum phosphorus, total magnesium and ionized calcium in the treatments. Weight gain was higher in animals fed with phosphorus supplementation in levels above 0.135%. The best result occurred with 0.330% P supplementation, however, an increase from 0.200% in the diet caused an elevation in phosphorus serum concentration.O objetivo deste trabalho foi avaliar o efeito de dietas, com diferentes teores de fósforo, no perfil eletrolítico sanguíneo e no ganho de peso corporal em suínos. Foram utilizados 60 suínos híbridos comerciais, machos castrados, com peso corporal médio inicial de 61,07±0,86 kg, com aproximadamente 110 dias de idade. Os animais foram distribuídos em blocos ao acaso, com 5 tratamentos e 12 repetições cada um. Os tratamentos foram constituídos de dietas com 0,135, 0,200, 0,265, 0,330 e 0,395% de fósforo disponível. No início e no final do período experimental, foi determinado o peso corporal e foram coletadas amostras de sangue, sem jejum dos animais, para a mensuração de sódio, potássio, cloreto, magnésio total, fósforo e cálcio ionizado. Observou-se resposta quadrática do peso corporal, de acordo com os tratamentos, e das concentrações séricas de fósforo, magnésio total e cálcio iônico em decorrência dos tratamentos. O ganho de peso corporal foi maior nos animais alimentados com suplementação de fósforo em teores acima de 0,135%. O melhor resultado foi obtido com a dieta de 0,330% de fósforo, porém, o aumento a partir de 0,200% na dieta ocasionou elevação na concentração sérica de fósforo

QTL mapping for growth traits of pigs using random regression models

O objetivo deste trabalho foi avaliar eficiência de modelos de regressão aleatória (MRA) para detectar locus de características quantitativas (QTL) para características de crescimento, em suínos. Utilizou-se uma população divergente F2 Piau x Comercial. A eficiência da metodologia proposta na detecção de QTL foi comparada à da metodologia tradicional de regressão por intervalo de mapeamento. Para tanto, utilizaram-se MRA com efeitos aleatórios poligênicos, de ambiente permanente e de QTL, tendo-se utilizado o enfoque de matriz de covariância “identical‑by‑descent” associada aos efeitos de QTL. Testou-se a significância dos efeitos de QTL mediante a razão de verossimilhanças, tendo-se considerado o modelo como completo quando houve efeito de QTL, ou nulo, quando não. A comparação entre os modelos foi feita nas posições dos marcadores (seis marcadores microssatélites) e nas intermediárias, entre os marcadores. O MRA detectou QTL significativo na posição 65 cM do cromossomo 7 e, portanto, foi mais eficiente que a metodologia tradicional, que não detectou QTL significativo em nenhum dos fenótipos avaliados. A metodologia proposta possibilitou a detecção de QTL com efeito sobre toda a trajetória de crescimento, dentro da amplitude de idade considerada (do nascimento aos 150 dias).  The objective of this work was to evaluate the efficiency of random regression models (RRM) to detect quantitative trait loci (QTL) for growth traits in pigs. An outbreed F2 Piau x Commercial population was used. The efficiency of the proposed methodology for QTL detection was compared to the traditional methodology of regression interval mapping. In order to do that, RRM with random polygenic effects of permanent environment and of QTL were used with the approach of the covariance matrix identical‑by‑descent, associated to the QTL effects. The significance of QTL effects was tested by the likelihood ratio, considering the described model as being complete when there was significant QTL effect, and null, when there was not. Comparison between models was made at the positions of the markers (six microsatellite markers) and at the intermediate positions between them. The RRM allowed the detection of a significant QTL at the position 65 cM of chromosome 7 and, therefore, it was considered more efficient than traditional method, which did not identify any significant QTL in any of the evaluated phenotypes. The proposed methodology enabled the detection of QTL affecting all growth trajectory within the considered age range (from birth to 150 days)

Uso da regressão quantílica regularizada para predição de mérito genético em suínos quanto a características assimétricas de carcaça

The objective of this work was to evaluate the use of regularized quantile regression (RQR) to predict the genetic merit of pigs for asymmetric carcass traits, compared with the Bayesian lasso (Blasso) method. The genetic data of the traits carcass yield, bacon thickness, and backfat thickness from a F2 population composed of 345 individuals, generated by crossing animals from the Piau breed with those of a commercial breed, were used. RQR was evaluated considering different quantiles (τ = 0.05 to 0.95). The RQR model used to estimate the genetic merit showed accuracies higher than or equal to those obtained by Blasso, for all studies traits. There was an increase of 6.7 and 20.0% in accuracy when the quantiles 0.15 and 0.45 were considered in the evaluation of carcass yield and bacon thickness, respectively. The obtained results are indicative that the regularized quantile regression presents higher accuracy than the Bayesian lasso method for the prediction of the genetic merit of pigs for asymmetric carcass variables.O objetivo deste trabalho foi avaliar o uso da regressão quantílica regularizada (RQR) para predição do mérito genético em suínos quanto a características assimétricas de carcaça, em comparação ao método do lasso bayesiano (Blasso). Foram utilizados dados genéticos das características rendimento de carcaça, espessura de bacon e espessura de toucinho de uma população F2 composta por 345 indivíduos, obtida pelo cruzamento de animais da raça Piau com os de raça comercial. A RQR foi avaliada tendo-se considerado diferentes quantis (τ = 0,05 a 0,95). O modelo de RQR utilizado para estimar o mérito genético apresentou acurácias maiores ou iguais àquelas obtidas pelo Blasso, para todas as características estudadas. Houve incremento de 6,7 e 20,0% na acurácia, quando se consideraram os quantis 0,15 e 0,45 na avaliação do rendimento de carcaça e da espessura de bacon, respectivamente. Os resultados obtidos são indicativos de que a regressão quantílica regularizada apresenta maior acurácia que o método lasso Bayesiano para predição do mérito genético de variáveis assimétricas de carcaça