PSVI-9 - Effects of dietary boron supplementation on growth performance, fasting and postprandial serum insulin, and glucose concentration of pigs

A 49-d experiment evaluated the effects of supplemental boron (B) on growth, and serum insulin and glucose concentration of pigs. Crossbred pigs [n = 48; initial body weight (BW) 19.18 ± 0.29 kg] were randomly allotted to 1 of 4 diets based on BW and sex. Diets were corn-SBM-based, formulated to meet NRC (2012) nutrient requirement estimates, and were supplemented with 0, 25, 50, or 100 mg B/kg diet as sodium tetraborate decahydrate. On d 20 and 41, blood samples were collected. Fasting samples were collected following an overnight fast; then a postprandial sample was taken approximately 50 minutes after the pigs had 10 minutes of ad libitum access to feed. Samples were processed and serum analyzed for insulin and glucose concentration. Increasing B levels resulted in a linear decrease for overall ADG (0.87, 0.86, 0.85, and 0.82 kg, P = 0.02). On d 20, supplemental B resulted in a quadratic response on fasting serum glucose concentration (5.25, 4.80, 4.65, and 5.01, P = 0.03) and a linear decrease in postprandial serum insulin concentration (29.1, 25.5, 18.2, and 18.1 µU/mL, P = 0.02). Furthermore, there was a tendency for a linear decrease in fasting insulin:glucose ratio (0.85, 0.84, 0.42, and 0.59, P = 0.08), which became more noticeable during the postprandial state (3.96, 3.63, 2.63, and 2.73, P = 0.02). Again on d 41, there was a quadratic response on fasting serum glucose concentration (4.32, 4.07, 3.91, and 4.68, P = 0.01) with supplemental B. Results suggest that supplemental boron may impact serum insulin and glucose concentrations by reducing the amount of insulin needed to maintain glucose concentrations. However, higher levels of supplemental boron did result in suppressed growth performance. Thus, additional research is warranted to determine the optimum level of supplemental B.