Analysis of horse myostatin gene and identification of single nucleotide polymorphisms in breeds of different morphological types.

Myostatin (MSTN) is a negative modulator of muscle mass. We characterized the horse (Equus caballus) MSTN gene and identified and analysed single nucleotide polymorphisms (SNPs) in breeds of different morphological types. Sequencing of coding, untranslated, intronic, and regulatory regions of MSTN gene in 12 horses from 10 breeds revealed seven SNPs: two in the promoter, four in intron 1, and one in intron 2. The SNPs of the promoter (GQ183900:g.26T>C and GQ183900:g.156T>C, the latter located within a conserved TATA-box like motif) were screened in 396 horses from 16 breeds. The g.26C and the g.156C alleles presented higher frequency in heavy (brachymorphic type) than in light breeds (dolichomorphic type such as Italian Trotter breed). The significant difference of allele frequencies for the SNPs at the promoter and analysis of molecular variance (AMOVA) on haplotypes indicates that these polymorphisms could be associated with variability of morphology traits in horse breeds.

Effect of ß-carotene Supplementation on Italian Trotter Mare Peripartum.

When the mare's estrous cycle resumes in winter, the ß-carotene content of hay is depleted. Sixty Italian trotter mares were randomly assigned to a Control or a Treated Group. Treated Group received 1g/d synthetic ß-carotene for 15 days from parturition. Blood samples collected at parturition and on days 5, 10 and 15 after partum were analysed for ß-carotene, vitamins A, progesterone, 17 ß-estradiol, the energy parameters (glucose, cholesterol, NEFA), the protein profile (total protein, albumin, urea) and LDH. Some changes in these measures were attributable to treatment, which significantly affected ß-carotene and 17 ß-estradiol concentrations. A significant effect was also found on the resumption of estrous activity (χ(2) test=P<0.052).