RESUMEN
The aim of this study was to estimate genetic parameters and identify genomic regions associated with carcass traits obtained by ultrasound and visual scores in Nellore cattle. Data from ~66,000 animals from the National Association of Breeders and Researchers (ANCP) were used. The variance components for backfat thickness, rump fat thickness and Longissimus muscle area (LMA) were estimated considering a linear model whereas a threshold model for body structure (BS), finishing precocity (FP) and musculature (MS) traits. The SNP solutions were estimated using the ssGBLUP approach by considering windows of 10 consecutive SNPs. Regions that accounted for more than 1.0% of the additive genetic variance were used. Genes identified within the significant windows, such as FOXA3, AP2S1, FKRP, NPASI and ATP6V1G1, were found to be related with MS, while OMA1 and FFGY with BS and FP traits. The PLTP, TNNC2 and GPAT2 genes were found in the regions associated with LMA, as well as TKT, FNDC5 and CHRND can strongly be related with fat deposition. Gene enrichment analysis revealed processes that might be directly influenced the organism growth and development. These results should help to better understand the genetic and physiological mechanisms regulating growth and body composition, muscle tissue development and subcutaneous fat expression, and this information might be useful for future genomic studies in Nellore cattle.
Asunto(s)
Composición Corporal/genética , Cruzamiento , Genoma/genética , Genómica , Animales , Bovinos , Músculos Paraespinales/crecimiento & desarrollo , Fenotipo , Polimorfismo de Nucleótido Simple/genética , Grasa Subcutánea/crecimiento & desarrolloRESUMEN
OBJECTIVE: To examine the relationship between brown adipose tissue (BAT) and muscle development, two tissues that derive from a common cell lineage, during the first 6 months of postnatal life. STUDY DESIGN: Thirty healthy term infants (15 males and females) underwent whole-body magnetic resonance imaging examinations. Measurements of BAT in the supraclavicular area as well as measures of trunk musculature and subcutaneous adiposity were obtained at birth and at 6 months of age. RESULTS: Paraspinous musculature and subcutaneous white adipose tissue (WAT) increased, and the proportion of BAT in the supraclavicular area decreased during infancy. Although measures of BAT did not correlate with paraspinous musculature through the first 6 months of life (r = -0.35; P = .09), BAT was a significant predictor of paraspinous musculature after adjusting for weight, body length, and WAT (P = .002); infants with the smallest decreases in BAT had the greatest gains in musculature. In contrast, changes in BAT did not predict increases in subcutaneous WAT (P = .25) during infancy, which were primarily determined by body weight. CONCLUSIONS: Changes in BAT are associated with muscle development but not WAT accumulation in healthy infants. Studies are needed to determine the mechanism(s) by which BAT could facilitate muscle growth, and the degree to which decreased muscle mass, such as in preterm and low birth weight infants, is related to a deficiency of BAT.
Asunto(s)
Tejido Adiposo Pardo/diagnóstico por imagen , Desarrollo de Músculos , Músculos Paraespinales/diagnóstico por imagen , Tejido Adiposo Blanco/diagnóstico por imagen , Femenino , Humanos , Lactante , Recién Nacido , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino , Músculos Paraespinales/crecimiento & desarrollo , Estudios Prospectivos , Análisis de Regresión , Nacimiento a TérminoRESUMEN
The extracellular matrix (ECM) is the major macromolecule in skeletal muscle, which affects meat quality greatly. The remodeling of the ECM is mainly regulated by matrix metalloproteinases (MMPs). The expression patterns of MMP-1, -2, and -8 in longissimus dorsi muscle were explored using quantitative real-time polymerase chain reaction. The results show that the expression of MMP-1, -2, and -8 decreased significantly from 135 days of pregnancy to postnatal 30 months. While the expression of MMP-1, -2, and -8 showed no significant relationships with intramuscular fat contents, MMP-1 and -2 showed significant negative correlations with the shearing force of the longissimus dorsi muscle in cattle. The expression of MMP-1 also showed a significant negative correlation with cooking loss and a positive correlation with water holding capacity. The expression levels of MMP-1 and -2 were usually higher in fat than in skeletal muscle tissue. The expression of MMP-8 was significantly higher in the mammary fat pad and the longissimus dorsi muscle than in all other tissues. This study indicates that the remodeling of the ECM has important effects both on the development of postnatal skeletal muscle and on meat quality.