Regulation of Folliculogenesis by Growth Factors in Piglet Ovary Exposed Prenatally to β-Hydroxy-β-Methylbutyrate (HMB)

Β-hydroxy-β-methylbutyrate (HMB) is one of the leucine metabolites with protein anabolic effects which makes it very popular among athletes. Previously, it was shown that HMB administered during the prenatal period reduced the pool of primordial follicles and increased the proportion of developing follicles in newborn piglets. This work is a further step to understand these morphological alterations. Therefore, the aim of this study was to examine the effect of prenatal HMB treatment on the expression of the Kit ligand, BMP-4, bFGF, and the IGF-1/IGF-1R system which are the main growth factors controlling follicular development. Excised ovaries from 12 newborn piglets, originated from the control (n=6) and HMB-treated (n=6) sows were used for immunohistochemical and western-blot analysis. The tested proteins were localized within egg nests and ovarian follicles. Furthermore, the western-blot assay indicated higher BMP-4, Kit ligand, and IGF-1R expression, while the level of bFGF and IGF-1 proteins decreased after HMB dietary treatment. These findings show that HMB included into sow diet can modulate the expression of growth factors and thereby alter ovarian morphology in offspring. Therefore, this study opens a discussion about the benefits and risks of the diet supplemented with HMB and its potential application in medicine and animal husbandry, and further research is necessary in this area.