Changes in the Lipid Metabolism of the Longissimus thoracis Muscle in Bulls When Using Different Feeding Strategies during the Growing and Finishing Phases.

The objective was to evaluate the supplementation strategy's effect on beef cattle during the growing phase and two systems during the finishing phase. One hundred and twenty young bulls were randomly divided in a 2 × 2 factorial design to receive either mineral (ad libitum) or protein + energy (3 g/kg body weight (BW)/day) during the growing phase and pasture plus concentrate supplementation (20 g/kg BW/day) or feedlot (25:75% corn silage:concentrate) during the finishing phase. Feedlot-fed bulls had meat (Longissimus thoracis-LT) with a higher content of lipids and saturated and monounsaturated fatty acids and a greater upregulation of stearoyl-CoA desaturase and sterol regulatory element-binding protein-1c than animals that fed on pasture (p < 0.05). On the other hand, pasture-fed bulls had meat with a higher content of α-linoleic acid, linolenic acid, and n6 and a greater n6:n3 ratio compared to the feedlot-fed group (p < 0.05). In addition, meat from pasture-fed bulls during the finishing phase had 17.6% more isocitrate dehydrogenase enzyme concentration than the feedlot group (p = 0.02). Mineral-fed and pasture-finished bulls showed down-regulation of peroxisome proliferator-activated receptor gamma (p < 0.05), while the bulls fed protein + energy and finished in the feedlot had higher carnitine palmitoyltransferase 2 expression (p ≤ 0.013). In conclusion, mineral or protein + energy supplementation in the growing does not affect the fatty acid composition of intramuscular fat of LT muscle. In the finishing phase, feeding bulls in the feedlot upregulates the lipogenic genes and consequently improves the intramuscular fat content in the meat.

Early Weaning Possibly Increases the Activity of Lipogenic and Adipogenic Pathways in Intramuscular Adipose Tissue of Nellore Calves.

This study aimed to evaluate by wide-expression profile analysis how early weaning at 120 days can alter the skeletal muscle metabolism of calves supplemented with a concentrated diet until the growth phase. Longissimus thoracis muscle samples were obtained by biopsy from two groups of calves, early weaned (EW; n = 8) and conventionally weaned (CW; n = 8) at two different times (120 days of age-T1 [EW] and 205 days of age-T2 [CW]). Next, differential gene expression analysis and functional enrichment of metabolic pathways and biological processes were performed. The results showed respectively 658 and 165 differentially expressed genes when T1 and T2 were contrasted in the early weaning group and when early and conventionally weaned groups were compared at T2. The FABP4, SCD1, FASN, LDLR, ADIPOQ, ACACA, PPARD, and ACOX3 genes were prospected in both comparisons described above. Given the key role of these differentially expressed genes in lipid and fatty acid metabolism, the results demonstrate the effect of diet on the modulation of energy metabolism, particularly favoring postnatal adipogenesis and lipogenesis, as well as a consequent trend in obtaining better quality cuts, as long as an environment for the maintenance of these alterations until adulthood is provided.

Effect of Cow-Calf Supplementation on Gene Expression, Processes, and Pathways Related to Adipogenesis and Lipogenesis in Longissimus thoracis Muscle of F1 Angus × Nellore Cattle at Weaning.

The aim of this study was to identify differentially expressed genes, biological processes, and metabolic pathways related to adipogenesis and lipogenesis in calves receiving different diets during the cow-calf phase. Forty-eight uncastrated F1 Angus × Nellore males were randomly assigned to two treatments from thirty days of age to weaning: no creep feeding (G1) or creep feeding (G2). The creep feed offered contained ground corn (44.8%), soybean meal (40.4%), and mineral core (14.8%), with 22% crude protein and 65% total digestible nutrients in dry matter. After weaning, the animals were feedlot finished for 180 days and fed a single diet containing 12.6% forage and 87.4% corn-based concentrate. Longissimus thoracis muscle samples were collected by biopsy at weaning for transcriptome analysis and at slaughter for the measurement of intramuscular fat content (IMF) and marbling score (MS). Animals of G2 had 17.2% and 14.0% higher IMF and MS, respectively (p < 0.05). We identified 947 differentially expressed genes (log2 fold change 0.5, FDR 5%); of these, 504 were upregulated and 443 were downregulated in G2. Part of the genes upregulated in G2 were related to PPAR signaling (PPARA, SLC27A1, FABP3, and DBI), unsaturated fatty acid synthesis (FADS1, FADS2, SCD, and SCD5), and fatty acid metabolism (FASN, FADS1, FADS2, SCD, and SCD5). Regarding biological processes, the genes upregulated in G2 were related to cholesterol biosynthesis (EBP, CYP51A1, DHCR24, and LSS), unsaturated fatty acid biosynthesis (FADS2, SCD, SCD5, and FADS1), and insulin sensitivity (INSIG1 and LPIN2). Cow-calf supplementation G2 positively affected energy metabolism and lipid biosynthesis, and thus favored the deposition of marbling fat during the postweaning period, which was shown here in an unprecedented way, by analyzing the transcriptome, genes, pathways, and enriched processes due to the use of creep feeding.

Genomic Regions Associated with the Position and Number of Hair Whorls in Horses.

The position and number of hair whorls have been associated with the behavior, temperament, and laterality of horses. The easy observation of whorls assists in the prediction of reactivity, and thus permits the development of better measures of handling, training, mounting, and riding horses. However, little is known about the genetics involved in the formation of hair whorls. Therefore, the aim of this study was to perform a genome-wide association analysis to identify chromosome regions and candidate genes associated with hair whorl traits. Data from 342 Quarter Horses genotyped for approximately 53,000 SNPs were used in an association study using a single-step procedure. The following traits were analyzed: vertical position of hair whorl on the head, number of whorls on the head, and number of whorls on the left and right sides of the neck. The traits had between one and three genomic windows associated. Each of them explained at least 4% of the additive variance. The windows accounted for 20-80% of additive variance for each trait analyzed. Many of the prospected genes are related to hair follicle growth. Some of these genes exert a pleiotropic effect on neurological and behavioral traits. This is the first indication of biological and physiological activity that might explain the association of hair whorls and temperament.

Fine-scale estimation of inbreeding rates, runs of homozygosity and genome-wide heterozygosity levels in the Mangalarga Marchador horse breed.

With the availability of high-density SNP panels and the establishment of approaches for characterizing homozygosity and heterozygosity sites, it is possible to access fine-scale information regarding genomes, providing more than just comparisons of different inbreeding coefficients. This is the first study that seeks to access such information for the Mangalarga Marchador (MM) horse breed on a genomic scale. To this end, we aimed to assess inbreeding levels using different coefficients, as well as to characterize homozygous and heterozygous runs in the population. Using Axiom ® Equine Genotyping Array-670k SNP (Thermo Fisher), 192 horses were genotyped. Our results showed different estimates: inbreeding from genomic coefficients (FROH ) = 0.16; pedigree-based (FPED ) = 0.008; and a method based on excess homozygosity (FHOM ) = 0.010. The correlations between the inbreeding coefficients were low to moderate, and some comparisons showed negative correlations, being practically null. In total, 85,295 runs of homozygosity (ROH) and 10,016 runs of heterozygosity (ROHet) were characterized for the 31 horse autosomal chromosomes. The class with the highest percentage of ROH was 0-2 Mbps, with 92.78% of the observations. In the ROHet results, only the 0-2 class presented observations, with chromosome 11 highlighted in a region with high genetic variability. Three regions from the ROHet analyses showed genes with known functions: tripartite motif-containing 37 (TRIM37), protein phosphatase, Mg2+ /Mn2+ dependent 1E (PPM1E) and carbonic anhydrase 10 (CA10). Therefore, our findings suggest moderate inbreeding, possibly attributed to breed formation, annulling possible recent inbreeding. Furthermore, regions with high variability in the MM genome were identified (ROHet), associated with the recent selection and important events in the development and performance of MM horses over generations.

Effect of the g.98535683A>G SNP in the CAST gene on meat traits of Nellore beef cattle (Bos indicus) and their crosses with Bos taurus.

The objective of this study was to estimate allele frequencies of the g.98535683A>G:BTAU7 SNP in the CAST gene in different genetic groups of beef cattle produced in Brazil (Nellore and their crosses with Bos taurus), and to evaluate associations between this polymorphism and meat traits. Five hundred animals from six different genetic groups were genotyped and phenotyped for shear force (SF), myofibrillar fragmentation index (MFI), rib eye area, backfat thickness, and total lipids. Alleles A and G of the SNP were detected in all genetic groups and the frequency of A was higher than G. Significant association (P<0.05) was observed between the polymorphism and meat tenderness (SF and MFI), in which genotype AA exhibited the best values. These results demonstrate for the first time the occurrence of the studied SNP in a Zebu breed and its potential application to the genetic improvement of meat tenderness in the Nellore breed (Bos indicus) and its crosses with Bos taurus.

Perspectiva del uso de marcadores moleculares en el mejoramiento genético de equinos de carreras de la raza cuarto de milla / Prospects of the use of molecular markers in the genetic breeding of racing quarter horses / Perspectivas do uso de mercadores moleculares no melhoramento genético de equinos de corrida da raça quarto de milha

La utilización de marcadores moleculares trae gran progreso para el mejoramiento genético de especies comerciales destinadas a la producción, como bovinos, porcinos y aves, principalmente con el aumento de la precisión de predicciones de valores genéticos y rapidez en la selección de animales superiores. Esto ocurrió por medio del uso de algunos pocos marcadores ligados a Locus de Características Cuantitativas QTL (Selección Asistida por Marcadores) o por la estimación de efectos de millones de ellos simultáneamente (Estudio de asociación del Genoma Completo GWAS o asociación Genómica GS). Sin embargo, en otras especies domésticas, incluyendo los equinos, el empleo de esta biotecnología aun es poco explorado. Los primeros estudios para identificar variantes genéticas ligadas a mejores desempeños en carreras fueron realizados recientemente en la raza Pura Sangre Ingles (PSI), resultando en la implantación de pruebas genéticas que auxilian a los criadores en la selección de animales con mayor potencial genético. Esta revisión tiene por objetivo describir la situación actual de los marcadores moleculares aplicados a los caballos de carrera y las perspectivas del uso en el mejoramiento genético de equinos de carrera Cuarto de Milla, raza de gran importancia en el mundo y también en Brasil.(AU)

The use of molecular markers has brought great progress to genetic breeding programs of commercial species aimed at production, such as cattle, pigs and poultry, especially with the increase of the accuracy of prediction of breeding values, allowing early selection of better animals. This occurred either through the use of a few markers linked to Locos of Quantitative Trait QTL (marker-assisted selection) or the estimation of the effects of thousands of them simultaneously (Genome Wide Association Studies GWAS or Genomic Selection GS). However, in other domestic species, including equine, the use of this biotechnology remains underexplored. The first studies to identify genetic variants linked to better performance in races were performed with Thoroughbred horses, resulting in the implementation of genetic tests that assist breeders in selecting animals with greater genetic potential. The objective of this review was to describe the current status of molecular markers applied to racehorses and prospects of their use in genetic improvement of racing Quarter Horses, an important breed in the world and also in Brazil.(AU)

A utilização de marcadores moleculares trouxe grande progresso ao melhoramento genético de espécies comerciais destinados a produção, como bovinos, suínos e aves, principalmente com o aumento da acurácia de predição de valores genéticos e precocidade na seleção de animais superiores. Isto ocorreu por meio do uso de alguns poucos marcadores ligados a Locos de Características Quantitativas QTL (Seleção Assistida por Marcadores) ou pela estimação de efeitos de milhares deles simultaneamente (Estudos de Ampla Associação do Genoma GWAS ou Seleção Genômica GS). Por outro lado, em outras espécies domésticas, incluindo os equinos, o emprego desta biotecnologia ainda é pouco explorado. Os primeiros estudos a identificar variantes genéticas ligadas a melhores desempenhos em corridas foram realizados recentemente na raça Puro-Sangue Inglês (PSI), resultando na implantação de testes genéticos que auxiliam criadores na seleção de animais com maior potencial genético. Esta revisão tem por objetivo descrever a atual situação dos marcadores moleculares aplicados à cavalos de corrida e as perspectivas do seu uso no melhoramento genético de equinos de corrida Quarto de Milha, raça de grande importância no mundo e também no Brasil.(AU)

Perspectiva del uso de marcadores moleculares en el mejoramiento genético de equinos de carreras de la raza cuarto de milla / Prospects of the use of molecular markers in the genetic breeding of racing quarter horses / Perspectivas do uso de mercadores moleculares no melhoramento genético de equinos de corrida da raça quarto de milha

La utilización de marcadores moleculares trae gran progreso para el mejoramiento genético de especies comerciales destinadas a la producción, como bovinos, porcinos y aves, principalmente con el aumento de la precisión de predicciones de valores genéticos y rapidez en la selección de animales superiores. Esto ocurrió por medio del uso de algunos pocos marcadores ligados a Locus de Características Cuantitativas QTL (Selección Asistida por Marcadores) o por la estimación de efectos de millones de ellos simultáneamente (Estudio de asociación del Genoma Completo GWAS o asociación Genómica GS). Sin embargo, en otras especies domésticas, incluyendo los equinos, el empleo de esta biotecnología aun es poco explorado. Los primeros estudios para identificar variantes genéticas ligadas a mejores desempeños en carreras fueron realizados recientemente en la raza Pura Sangre Ingles (PSI), resultando en la implantación de pruebas genéticas que auxilian a los criadores en la selección de animales con mayor potencial genético. Esta revisión tiene por objetivo describir la situación actual de los marcadores moleculares aplicados a los caballos de carrera y las perspectivas del uso en el mejoramiento genético de equinos de carrera Cuarto de Milla, raza de gran importancia en el mundo y también en Brasil.

The use of molecular markers has brought great progress to genetic breeding programs of commercial species aimed at production, such as cattle, pigs and poultry, especially with the increase of the accuracy of prediction of breeding values, allowing early selection of better animals. This occurred either through the use of a few markers linked to Locos of Quantitative Trait QTL (marker-assisted selection) or the estimation of the effects of thousands of them simultaneously (Genome Wide Association Studies GWAS or Genomic Selection GS). However, in other domestic species, including equine, the use of this biotechnology remains underexplored. The first studies to identify genetic variants linked to better performance in races were performed with Thoroughbred horses, resulting in the implementation of genetic tests that assist breeders in selecting animals with greater genetic potential. The objective of this review was to describe the current status of molecular markers applied to racehorses and prospects of their use in genetic improvement of racing Quarter Horses, an important breed in the world and also in Brazil.

A utilização de marcadores moleculares trouxe grande progresso ao melhoramento genético de espécies comerciais destinados a produção, como bovinos, suínos e aves, principalmente com o aumento da acurácia de predição de valores genéticos e precocidade na seleção de animais superiores. Isto ocorreu por meio do uso de alguns poucos marcadores ligados a Locos de Características Quantitativas QTL (Seleção Assistida por Marcadores) ou pela estimação de efeitos de milhares deles simultaneamente (Estudos de Ampla Associação do Genoma GWAS ou Seleção Genômica GS). Por outro lado, em outras espécies domésticas, incluindo os equinos, o emprego desta biotecnologia ainda é pouco explorado. Os primeiros estudos a identificar variantes genéticas ligadas a melhores desempenhos em corridas foram realizados recentemente na raça Puro-Sangue Inglês (PSI), resultando na implantação de testes genéticos que auxiliam criadores na seleção de animais com maior potencial genético. Esta revisão tem por objetivo descrever a atual situação dos marcadores moleculares aplicados à cavalos de corrida e as perspectivas do seu uso no melhoramento genético de equinos de corrida Quarto de Milha, raça de grande importância no mundo e também no Brasil.