The effect of insulin-like growth factor 1 receptor gene single nucleotide polymorphism on growth and milk production traits in two native Indian tropical goat breeds.

Insulin like growth factor1(IGF-1) is an essential growth factor that mediates the growth-promoting functions of pituitary growth hormone. Insulin like growth factor 1 receptor (IGF1R) is a tyrosine kinase receptor that mediates the actions of IGF1. Therefore, IGF1R is a candidate gene for examining SNPs linked with growth and production traits. The objective of this study was to detect the c.546 + 179170A > T transversion in intron 2 of the gene encoding IGF1R in two goat breeds, Attappady Black and Malabari, and examine the association of this polymorphism with growth and milk production. For the identification of the SNP, the T-ARMS-PCR was utilized. All three genotypes were present in the two investigated breeds. The polymorphism was found to be significantly (p < 0.05) linked with growth traits. At birth, 3 and 6 months of age, Attappady goats with the AT genotype had significantly (p < 0.05) higher body weights than those with the AA and TT genotypes. Malabari goats with the AT genotype had significantly (p < 0.05) higher body weights at birth and at 3 months of age. The genotypes of the IGF1R gene had no effect on total or peak milk production. Therefore, this SNP could be used as a molecular marker in selection of meat-producing goat breeds.HIGHLIGHTSc.546 + 179170A > T IGF1R transversion was detected using T-ARMS-PCR in two indigenous goat breeds from Kerala.Attappady Black and Malabari goat breeds of Kerala possessed all the three genotypesIn these breeds, there was a significant correlation between this SNP, c.546 + 179170A > T IGF1R, and body weight.In both the breeds, there was no association between this SNP and milk production traits.

Participation of the adenosine salvage pathway and cyclic AMP modulation in oocyte energy metabolism.

A follicular spike in cyclic AMP (cAMP) and its subsequent degradation to AMP promotes oocyte maturation and ovulation. In vitro matured (IVM) oocytes do not receive the cAMP increase that occurs in vivo, and artificial elevation of cAMP in IVM cumulus-oocyte complexes improves oocyte developmental potential. This study examined whether mouse oocytes can use the cAMP degradation product AMP to generate ATP via the adenosine salvage pathway, and examined whether pharmacological elevation of cAMP in IVM cumulus-oocyte complexes alters ATP levels. Oocytes cultured with isotopic 13C5-AMP dose-dependently produced 13C5-ATP, however total cellular ATP remained constant. Pharmacological elevation of cAMP using forskolin and IBMX prior to IVM decreased oocyte ATP and ATP:ADP ratio, and promoted activity of the energy regulator AMPK. Conversely, cumulus cells exhibited higher ATP and no change in AMPK. Culture of oocytes without their cumulus cells or inhibition of their gap-junctional communication yielded lower oocyte 13C5-ATP, indicating that cumulus cells facilitate ATP production via the adenosine salvage pathway. In conclusion, this study demonstrates that mouse oocytes can generate ATP from AMP via the adenosine salvage pathway, and cAMP elevation alters adenine nucleotide metabolism and may provide AMP for energy production via the adenosine salvage pathway during the energetically demanding process of meiotic maturation.

B-vitamin and homocysteine status determines ovarian response to gonadotropin treatment in sheep.

Maternal B-vitamin status and homocysteinemia can affect fertility and pregnancy establishment, although the direct effects on ovarian follicle and oocyte development are not known. We report on the effects of restricting the supply of vitamin B(12) and methionine from the diet of mature female sheep on ovarian folliculogenesis following follicle-stimulating hormone (FSH) stimulation. The study was split into three batches and involved 76 animals. Surprisingly, the number of growing, estrogen-active antral follicles following FSH treatment was enhanced (P = 0.005) following this dietary intervention. This increase occurred even in the presence of modest live-weight loss (batch 1 only) and depressed plasma insulin concentrations, suggesting a breakdown in the regulation of follicular responsiveness to FSH. This dietary intervention also increased plasma homocysteine concentrations. Physiological concentrations of homocysteine increased granulosa cell proliferation (P < 0.001), estradiol production (P = 0.05), and FSHR transcript expression (P = 0.017) during culture. Transcript levels for growth differentiation factor 9 and bone morphogenetic protein 15 in oocytes from treated ewes were increased (P < 0.05) in the first two batches. Furthermore, regression of BMP receptor 2 (BMPR2) transcript expression and diet on follicle number revealed a significant interaction (P = 0.01); BMPR2 transcript expression was associated with follicle number only in vitamin B(12)/methionine-restricted animals. Because FSHR transcript expression also was positively (P = 0.007) related to follicle number, the effects of diet may have arisen through enhanced FSH and BMP signaling. Although this remains to be confirmed, the data support an intraovarian impact of vitamin B(12)/methionine-deficient diets.