Effects of low-phytic acid corn on growth performance, bone strength, and serum osteocalcin concentration in growing-finishing pigs

Abstract

A 91-d experiment was conducted to evaluate whether low-phytic acid corn (NDLP, Exseed Genetics) (90% phosphorus (P) availability) could replace dent corn (DC) without adversely affecting growth performance or bone parameters in growing-finishing pigs. Total Pand phytate P were 0.24 and 0.16% in DC; 0.32 and 0.03% in NDLP, by analysis. Pigs were blocked by initial BW (18.5 to 22.5 kg) into four pens per treatment (trt) of eight crossbred pigs per pen. Two trts were fed; trt 1 contained DC and trt 2 contained NDLP. Three phases were fed; each was four wks in length. Dietary calcium and non-phytate Pw ere computed to provide 0.75 and 0.36, 0.63 and 0.30, or 0.55 and 0.28% in phases I, II, and III, respectively. Total Pw as computed to provide 0.57, 0.50, or 0.47% for trt 1; and 0.47, 0.40, or 0.36% for trt 2, in phases I, II, and III, respectively. Dicalcium phosphate concentration was decreased by 0.73, 0.78, and 0.85% units in trt 2, for phases I, II, and III, respectively. One gilt per pen was chosen, based on average pen BW (92 to 106 kg), for slaughter at 91d. All third and fourth metacarpals (MC) and metatarsals (MT) were used to analyze bone-breaking strength. Blood was collected from two pigs per pen at 90d for serum osteocalcin (OC) analysis (an indicator of bone turnover). Gain/feed (trt 1 = 316, trt 2 = 350, P > 0.09), BW (trt 1 = 97.3 kg, trt 2 = 98.7 kg, P > 0.71), and ADG (trt 1 = 840 g/d, trt 2 = 860 g, P > 0.57) were not affected. There were no differences in bone strength of third and fourth MC and fourth MT bones (P > 0.28). Overall, MC and MT bone strength was higher (15.04 vs. 12.83 MPa, P 0.92), suggesting no difference in bone turnover. This study proposes that NDLPcorn can be formulated with 90% Pa vailability and replace dent corn without adversely affecting pig performance