|Armstrong, Todd - NORTH CAROLINA STATE U|
|Flowers, William - NORTH CAROLINDA STATE U|
|Spears, Jerry - NORTH CAROLINA STATE U|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 17, 2001
Publication Date: January 1, 2002
Citation: Armstrong, T.A., Flowers, W.L., Spears, J.W., Nielsen, F.H. 2002. Long-term effects of boron supplementation on reproductive characteristics and bone mechanical properties in gilts. Journal of Animal Science. 80:154-161. Interpretive Summary: Recent research has shown that boron is needed in the early stages of life for some non-mammalian animal species. Lack of dietary boron adversely affected reproduction and embryo development in the African clawed frog and zebrafish. Thus, an experiment was performed with pigs to ascertain whether low dietary boron would affect reproductive characteristics in a mammal. The experiment also examined the effects of dietary boron on bone characteristics because findings with humans and other animals indicate that low intakes of boron can adversely affect bone formation or maintenance. Low dietary boron tended to decrease the number of live and increase the number of dead and mummified embryos present in the uterus at day 35 of gestation. Boron supplementation increased pig birth weight. Some bone strength measures were increased by boron supplementation. Low dietary boron decreased the concentrations of boron in muscle, liver and reproductive tissue. Low dietary boron increased the concentration of calcium in the uterus, embryo, and oviduct, and decreased phosphorus concentrations in the uterus, ovary and liver. The changes in calcium and phosphorus concentrations support the concept that boron has a role cell membrane function, composition or stability. Changes in cell membrane function or calcium distribution might have some role in the finding of increased mummified fetuses and possibly impaired reproductive function with the low dietary intake of boron. Overall, the findings suggest that boron is beneficial for reproduction and bone in mammals.
Technical Abstract: An experiment was conducted to determine long-term effects of dietary boron (B) on reproductive and bone characteristics in gilts. Fifty weanling gilts were allotted to 10 pens randomly assigned to receive a basal diet low in B (control) or the basal diet supplemented with 5 mg B/kg diet as sodium borate. Gilts remained on their respective experimental diets throughout the nursery phase, growing-finishing phase, sexual maturity, breeding, gestation, and lactation. Eight randomly selected gilts per treatment were slaughtered at d 35 of gestation for the assessment of embryonic and reproductive characteristics, cone characteristics, and tissue B concentrations. The remaining pregnant gilts (control, n = 11; 5 mg supplemental B/kg diet, n - 10) farrowed, and litter characteristics at farrowing and weaning were determined. Age at puberty was not affected by B, and neither were the number of corpora lutea on the ovaries or the total number of embryos at day 35 of gestation. However, B tended to increase the number of live and decrease the number of dead embryos present in the uterus at d 35 of gestation. Boron supplementation increased (P< 0.05) pig weaning weight and tended to increase pig birth weight; however, no other litter characteristics were affected by B. Extrinsic and intrinsic strength measures of bone were increased by 27.2 and 13.7%, respectively, by B. Fat-free bone ash percentage and bone mineral concentrations were not affected by dietary B. Supplemental B increased (P < 0.05) the B concentrations of the muscle, liver, and reproductive tissues. Serum osteocalcin concentrations tended to be increased by dietary B. Boron may have beneficial effects upon reproductive and bone characteristics.