Drone brood fed supplement impacts on the folliculogenesis in growing gilts

Abstract

The biological properties of bee drone brood make it an ideal additive for growth promotion in animal husbandry instead of banned hormonal anabolics and antibiotics. However, the drone brood action on mammalian ovaries has not been well studied. The present study analyzes the impact of drone brood homogenate (DBH) in the diet of growing gilts on folliculogenesis. Large White female pigs at the age of 35 days were randomly divided into two groups of 10 animals each, and fed with the same basal diets. The experimental group was supplemented with 25 mg/kg forage of DBH for 180 days, after which the animals were slaughtered and morphometric, histological and immunohistochemical evaluation of their ovaries was performed. In addition, the expression of ovarian growth factors BMP15 and GDF9 in oocytes and cumulus cells was analyzed by RT-PCR. A significant increase in body weight and average daily gain at day 145 in the DBH-supplemented group was established. The length of the ovaries in the treated animals also was enhanced. More pools of primordial follicles, involved in intensive growth, as well as a larger diameter of primary and tertiary follicles were found in the ovaries of DBH-supplemented animals. These findings corresponded with an increase in the expression of GDF9 mRNA in the oocytes and cumulus cells. At the same time, signs of atresia in the Graafian follicles of treated animals were observed. The supplementation with DBH stimulates the early stages of folliculogenesis in gilts, but provokes atresia in the last stage of follicular development.