RESUMO

We aimed to evaluate the impact of nutrient supplementation of beef female calves at pre-weaning on adipogenic determination. Thirty-four female calves were assigned to two experimental treatments: Control (CON, n = 17), where animals were supplemented only with mineral mixture; Supplemented (SUP, n = 17), where animals received energy-protein supplement containing minerals (5 g/kg of BW per day) of their body weight. Animals were supplemented from 100 to 250 days of age, and muscle samples were biopsied at the end of the supplementation period. Regarding the performance variables, there were no differences between treatments for initial body weight (P = 0.75). The final body weight (P = 0.07), average daily gain (P = 0.07), rib eye area (P = 0.03), and rib fat thickness (P = 0.08) were greater in SUP female calves compared with CON treatment. The number of fibro-adipogenic progenitor cells (P = 0.69) did not differ between treatments, while a greater number of intramuscular pre-adipocytes were observed in SUP than CON female calves (P = 0.01). The expression of miRNA-4429 (P = 0.20) did not differ between treatments, while the expression of miRNA-129-5p (P = 0.09) and miRNA-129-2-3p (P = 0.05) was greater in CON than SUP female calves. Our results suggest that nutrient supplementation at early postnatal stages of development enhances the commitment of fibro-adipogenic progenitor cells into the adipogenic lineages allowing to an increase in intramuscular fat deposition potential of the animals later in life.

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RESUMO

The aim of the present study was to propose and evaluate the use of factor analysis (FA) in obtaining latent variables (factors) that represent a set of pig traits simultaneously, for use in genome-wide selection (GWS) studies. We used crosses between outbred F2 populations of Brazilian Piau X commercial pigs. Data were obtained on 345 F2 pigs, genotyped for 237 SNPs, with 41 traits. FA allowed us to obtain four biologically interpretable factors: "weight", "fat", "loin", and "performance". These factors were used as dependent variables in multiple regression models of genomic selection (Bayes A, Bayes B, RR-BLUP, and Bayesian LASSO). The use of FA is presented as an interesting alternative to select individuals for multiple variables simultaneously in GWS studies; accuracy measurements of the factors were similar to those obtained when the original traits were considered individually. The similarities between the top 10% of individuals selected by the factor, and those selected by the individual traits, were also satisfactory. Moreover, the estimated markers effects for the traits were similar to those found for the relevant factor.

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Among several potential animal models that can be used for adipogenic studies, Wagyu cattle is the one that presents unique molecular mechanisms underlying the deposit of substantial amounts of intramuscular fat. As such, this review is focused on current knowledge of such mechanisms related to adipose tissue deposition using Wagyu cattle as model. So abundant is the lipid accumulation in the skeletal muscles of these animals that in many cases, the muscle cross-sectional area appears more white (adipose tissue) than red (muscle fibers). This enhanced marbling accumulation is morphologically similar to that seen in numerous skeletal muscle dysfunctions, disease states and myopathies; this might indicate cross-similar mechanisms between such dysfunctions and fat deposition in Wagyu breed. Animal models can be used not only for a better understanding of fat deposition in livestock, but also as models to an increased comprehension on molecular mechanisms behind human conditions. This revision underlies some of the complex molecular processes of fat deposition in animals.

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Pig is an important animal for meat production; this is generally associated with characteristics determined prenatally during myogenesis. Expressed sequence tags (EST) can provide direct information on the transcriptome and indirect information on the relation between the genome and phenotype, giving information about differentially expressed genes (DEG). In this work, the identification and annotation of DEG from EST libraries of three pig breeds (Duroc, Large White and Local Breed Piau) were performed followed by real-time PCR analyses during pre- and postnatal stages (21, 40, 70 and 90 days of pregnancy and 107, 121 and 171 days postnatal) from commercial breed animals for analysis of genes expression levels. Therefore, 34 genes differentially expressed were identified, of which 21 grouped in a network related with muscle development. From this, the expression profile of 13 genes was measured, to confirm their relationship with myogenesis like ANKRD2, MYBPC1, NEB and MYL2. These genes showed a prenatal high expression in this study. Besides, novels candidates for muscle development (TP53 and DCTN1) were listed. These findings can contribute to better explaining gene function mechanism and are helpful in uncovering the pathways that mediate pre- and postnatal skeletal muscle development in vertebrates.

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RESUMO

Mapeou-se quantitative trait loci (QTL) associados a características de desempenho nos cromossomos 1, 2, 3, 12, 14, 15 e X de suínos pertencentes a uma população F2, formada a partir do cruzamento entre dois machos da raça naturalizada brasileira Piau e 18 fêmeas comerciais (Landrace x Large White x Pietrain). O mapa genético de ligação da população foi construído após a genotipagem dos animais para 35 marcadores microssatélites. As estimativas do conteúdo de informação polimórfica indicaram que os marcadores microssatélites foram adequados para as análises de QTL. Os dados foram analisados pelo mapeamento por intervalo usando-se o programa GridQTL. Encontraram-se seis QTL, sendo que o QTL genômico para idade ao abate atingiu a significância de 5% de probabilidade. As informações dos QTL detectados neste estudo são úteis para identificar genes que podem ser usados em conjunto com os métodos convencionais de seleção, aumentar a acurácia deles e prover uma compreensão dos fenótipos produtivos de suínos.

The accomplishment of the present study had the objective of mapping Quantitative Trait Loci (QTL) related to performance traits in a F2 pig population developed by mating two Brazilian Piau breed sires with 18 dams from a commercial line (Landrace × Large White × Pietrain). The linkage map for this population was constructed after genotyping the animals for 35 microsatellite markers. Estimates of polymorphic information content indicated that the microsatellite markers were appropriate for QTL analyses. The genotypes were analyzed by interval mapping using the GridQTL program. A total of six QTL were found, of which the QTL for slaughter age (days) was significant at the 5% genome-wise level. The information of the significant QTL detected in this study is useful for future fine-mapping studies for the identification of genes. Such information can be used together with traditional methods in breeding programs or even for a better understanding of the phenotypes of swine production.

Assuntos

RESUMO

Mapeou-se quantitative trait loci (QTL) associados a características de desempenho nos cromossomos 1, 2, 3, 12, 14, 15 e X de suínos pertencentes a uma população F2, formada a partir do cruzamento entre dois machos da raça naturalizada brasileira Piau e 18 fêmeas comerciais (Landrace x Large White x Pietrain). O mapa genético de ligação da população foi construído após a genotipagem dos animais para 35 marcadores microssatélites. As estimativas do conteúdo de informação polimórfica indicaram que os marcadores microssatélites foram adequados para as análises de QTL. Os dados foram analisados pelo mapeamento por intervalo usando-se o programa GridQTL. Encontraram-se seis QTL, sendo que o QTL genômico para idade ao abate atingiu a significância de 5% de probabilidade. As informações dos QTL detectados neste estudo são úteis para identificar genes que podem ser usados em conjunto com os métodos convencionais de seleção, aumentar a acurácia deles e prover uma compreensão dos fenótipos produtivos de suínos.(AU)

The accomplishment of the present study had the objective of mapping Quantitative Trait Loci (QTL) related to performance traits in a F2 pig population developed by mating two Brazilian Piau breed sires with 18 dams from a commercial line (Landrace × Large White × Pietrain). The linkage map for this population was constructed after genotyping the animals for 35 microsatellite markers. Estimates of polymorphic information content indicated that the microsatellite markers were appropriate for QTL analyses. The genotypes were analyzed by interval mapping using the GridQTL program. A total of six QTL were found, of which the QTL for slaughter age (days) was significant at the 5% genome-wise level. The information of the significant QTL detected in this study is useful for future fine-mapping studies for the identification of genes. Such information can be used together with traditional methods in breeding programs or even for a better understanding of the phenotypes of swine production.(AU)

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RESUMO

A realização do presente estudo teve como objetivo mapear Quantitative Trait Loci (QTL) de carcaça e qualidade de carne em uma população F2 de suínos desenvolvida pelo cruzamento de dois reprodutores da raça brasileira Piau com 18 fêmeas comerciais (Landrace x Large White x Pietrain). O mapa de ligação para essa população foi construído após a genotipagem de 684 animais para 35 marcadores microssatélites. Os dados foram analisados pelo mapeamento por intervalo usando-se sexo, lote e genótipo halotano como efeitos fixos e peso de carcaça ao abate, peso da carcaça direita e idade ao abate como covariáveis. Um total de 18 QTLs foi encontrado; os QTLs para maior espessura de toucinho na região da copa, na linha dorsolombar, e a perda por cozimento foram significativos em nível de 5% genômico. A característica espessura de toucinho foi essencialmente associada aos alelos da raça Piau, conhecido como porco tipo banha. As informações dos QTLs significativos encontrados servem para futuros estudos de mapeamento fino para identificação de genes a serem usados em conjunto com os métodos tradicionais de seleção, para melhorar a eficiência dos programas de melhoramento, assim como prover informação acerca da fisiologia envolvida no desenvolvimento das características quantitativas dos suínos.

The accomplishment of the present study had as objective to map Quantitative Trait Loci (QTL) associated to carcass and quality traits in a F2 pig population developed by mating two Brazilian Piau breed sires with 18 dams from a commercial line (Landrace × Large White × Pietrain). The linkage map for this population was constructed after genotyping the 684 animals for 35 microsatellite markers. Data were analyzed by interval mapping using sex, batch and halothane genotype as fixed effects and carcass weight at slaughter, direct carcass weight and slaugher age as covariables. A total of 18 QTL were identified, the QTL for higher backfat thickness on the shoulder region and cooking loss was significant at 5% genome-wise level. The backfat thickness trait was mainly associated with the Piau breed allele, known as a fat pig. The information of the significant QTL detected in this study is useful for future fine-mapping studies for identification of genes and might be used together with traditional selection methods to improve the efficiency of breeding programs, moreover, this information can also provide new insights to the understanding of the physiology of the quantatiative traits in pigs.

Assuntos

RESUMO

In general, genetic differences across different breeds of pig lead to variation in mature body size and slaughter age. The Commercial breeds Duroc and Large White and the local Brazilian breed Piau are ostensibly distinct in terms of growth and muscularity, commercial breeds are much leaner while local breeds grow much slower and are fat type pigs. However, the genetic factors that underlie such distinctions remain unclear. We used expressed sequence tags (ESTs) to characterize and compare transcript profiles in the semimembranosus muscle of these pig breeds. Our aim was to identify differences in breed-related gene expression that might influence growth performance and meat quality. We constructed three non-normalized cDNA libraries from semimembranosus muscle, using two samples from each one, of these three breeds; 6902 high-quality ESTs were obtained. Cluster analysis was performed and these sequences were clustered into 3670 unique sequences; 24.7% of the sequences were categorized as contigs and 75.3% of the sequences were singletons. Based on homology searches against the SwissProt protein database, we were able to assign a putative protein identity to only 1050 unique sequences. Among these, 58.5% were full-length protein sequences and 17.2% were pig-specific sequences. Muscle structural and cytoskeletal proteins, such as actin, and myosin, were the most abundant transcripts (16.7%) followed by those related to mitochondrial function (12.9%), and ribosomal proteins (12.4%). Furthermore, ESTs generated in this study provide a rich source for identification of novel genes and for the comparative analysis of gene expression patterns in divergent pig breeds.

Assuntos

RESUMO

A realização do presente estudo teve como objetivo mapear Quantitative Trait Loci (QTL) de carcaça e qualidade de carne em uma população F2 de suínos desenvolvida pelo cruzamento de dois reprodutores da raça brasileira Piau com 18 fêmeas comerciais (Landrace x Large White x Pietrain). O mapa de ligação para essa população foi construído após a genotipagem de 684 animais para 35 marcadores microssatélites. Os dados foram analisados pelo mapeamento por intervalo usando-se sexo, lote e genótipo halotano como efeitos fixos e peso de carcaça ao abate, peso da carcaça direita e idade ao abate como covariáveis. Um total de 18 QTLs foi encontrado; os QTLs para maior espessura de toucinho na região da copa, na linha dorsolombar, e a perda por cozimento foram significativos em nível de 5% genômico. A característica espessura de toucinho foi essencialmente associada aos alelos da raça Piau, conhecido como porco tipo banha. As informações dos QTLs significativos encontrados servem para futuros estudos de mapeamento fino para identificação de genes a serem usados em conjunto com os métodos tradicionais de seleção, para melhorar a eficiência dos programas de melhoramento, assim como prover informação acerca da fisiologia envolvida no desenvolvimento das características quantitativas dos suínos.(AU)

The accomplishment of the present study had as objective to map Quantitative Trait Loci (QTL) associated to carcass and quality traits in a F2 pig population developed by mating two Brazilian Piau breed sires with 18 dams from a commercial line (Landrace × Large White × Pietrain). The linkage map for this population was constructed after genotyping the 684 animals for 35 microsatellite markers. Data were analyzed by interval mapping using sex, batch and halothane genotype as fixed effects and carcass weight at slaughter, direct carcass weight and slaugher age as covariables. A total of 18 QTL were identified, the QTL for higher backfat thickness on the shoulder region and cooking loss was significant at 5% genome-wise level. The backfat thickness trait was mainly associated with the Piau breed allele, known as a fat pig. The information of the significant QTL detected in this study is useful for future fine-mapping studies for identification of genes and might be used together with traditional selection methods to improve the efficiency of breeding programs, moreover, this information can also provide new insights to the understanding of the physiology of the quantatiative traits in pigs.(AU)

Assuntos

RESUMO

Seventy-two pigs of three genetic groups (Brazilian indigenous breed Piau, Commercial line and Crossbred) of both sexes were slaughtered at four live weights (30, 60, 90 and 120 kg). Intramuscular fat (IMF) content in Longissimus dorsi muscle of each animal was extracted and correlated with candidate gene mRNA expression (ATN1, EEF1A2, FABP3, LDLR, MGP, OBSCN, PDHB, TRDN and RYR1). Within slaughter weight of 120 kg, Piau and Crossbred pigs showed higher IMF content (p < 0.05) than commercial animals, with 2.48, 2.08 and 1.00% respectively. Barrows presented higher values of IMF (p < 0.05) than gilts (1.54 and 1.30% respectively). Gene expression of EEF1A2, FABP3, LDLR, OBSCN, PDHB, TRDN and RYR1 were correlated with IMF (p < 0.05) using the whole dataset. For Piau data only, expression of FABP3, LDLR, MGP, OBSCN, PDHB, TRDN and RYR1 showed correlation with IMF (p < 0.05). Genes that have important roles in lipid transportation inside the cell (FABP3) and tissues (LDLR) showed correlation with IMF of, respectively, 0.68 and 0.63 using the whole data set, and 0.90 and 0.91 using data from Piau animals. The highly positive correlation of the LDLR and FAPB3 expression with IMF content may confirm that these genes are important for fat deposition in the porcine L. dorsi muscle.

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