The Effects of Dietary Fructose and Fat on the Reproductive Parameters of Prepubertal and Pregnant Gilts
Body adiposity is generally considered the most pertinent factor in puberty attainment; however, recent data suggests that pre-pubertal reproductive tract development may be altered by dietary sugar consumption. Two experiments were conducted to delineate the direct effects of fructose on the maturation of the pre-pubertal reproductive tract and fertility. At three weeks of age, forty gilts were placed on one of five dietary treatments (n=8) containing 15% fat (FAT), 35% fructose (FRU), both fat and fructose (HFHF), or two different controls: one standard industry (IND) diet meant to result in optimal lean growth and a second diet to account for the reduced lysine (LYS) intake in the treatment diets. Body weights did not differ amongst any of the five treatments on the day of sacrifice (P=0.32). As a percentage of BW, total reproductive tracts were heavier in fructose fed gilts (1.3±0.1 v. 0.8±0.1%; P=0.01) compared to non-fructose gilts. In the second experiment, starting at 130d of age, gilts were checked twice daily for puberty attainment. Gilts that attained puberty were artificially inseminated (AI) on their third estrous cycle. On gestational day 38±3, pregnant gilts were harvested for reproductive tract collection. Fewer fructose fed (FRU and HFHF) pigs became pregnant than non-fructose fed (IND, LYS, and FAT) gilts (25% v. 75% respectively; P=0.03). All HFHF gilts failed to become pregnant. Placental weights were greater in LYS fetuses than FAT fetuses (79.07 ± 6.55g v. 47.26 ± 6.45g, respectively, P= 0.04). Taken together, these results demonstrate that fructose consumption increases reproductive tract size, but that reproductive capabilities are reduced.