Nutrient Requirements Boron Supplementation of a Semipurified Diet for Weanling Pigs Improves Feed Efficiency and Bone Strength Characteristics and Alters Plasma Lipid Metabolites1,2,3

Two experiments were conducted to determine effects of dietary boron (B) on performance, plasma minerals and metabolites, and bone characteristics in young pigs. In Experiment 1, 48 pigs (24 males, 24 females; 21 d old) were allotted to pens, which were randomly assigned to one of the following dietary treatments: 1) control (natural ingredient diet; 6.7 mg B/kg diet), 2) control 1 5 mg B/kg diet and 3) control 1 15 mg B/kg diet. Boron was supplemented as sodium borate. In Experiment 2, 48 pigs (24 males, 24 females; 21 d old) were assigned to the same treatments described in Experiment 1; however, the basal diet was a semipurified diet (0.98 mg B/kg diet). Diets were fed for 40 d; on d 40, blood samples were obtained for determination of plasma mineral and metabolite concentrations. Femurs were harvested from 8 pigs per treatment on d 40 for determination of mechanical properties, ash and lipid percentage. In Experiment 1, B did not affect performance, plasma minerals or metabolites or bone properties. In Experiment 2, B supplementation improved (P , 0.05) the gain:feed ratio and increased plasma cholesterol and triglyceride concentrations. There was a treatment 3 sex interaction (P , 0.05) in Experiment 2 for bone lipid to be lower and bending moment to be higher, with the response occurring in male pigs. Other dependent variables in Experiment 2 were not affected by treatment. In conclusion, B supplementation of a low B diet elicited responses of physiologic importance to pigs. However, B supplementation of a natural ingredient diet did not elicit a response. J. Nutr. 139: 2575–2581, 2000.