363 Increased Intestinal Alkaline Phosphatase Maximal Activities Mediate Improvements in Growth and Gut Health Status in Weanling Pigs Fed the Antibiotic-Supplemented Diet.

Abstract

Improved understanding of the biological mechanisms of antibiotic actions on improving growth rate and gut health aids to develop alternative strategies in weanling pig nutrition. We hypothesized that dietary antibiotic could improve growth performance and gut health by enhancing the intestinal endogenous alkaline phosphatase detoxification capacity in weanling pigs. A total of 104 crossbred (Duroc × Yorkshire × Landrace) barrows were weaned at d 19, with an average initial BW of 6.81; SE=0.09 kg BW, from 62 litters; and were randomly assigned to two groups according to a randomized complete block design. Both groups of pigs were fed a corn and SB-based diet for 3 weeks; and the antibiotic-treatment diet was supplemented with 550 mg aureomycin per kg diet. The dietary antibiotic supplementation increased (PPp-nitrophenyl phosphate as a substrate ranging 0 – 0.8 mM in incubation media at pH 7.4 and 37 ºC for 30 minutes (parameter estimates±SE, P2 = 0.33 – 0.83, n=40). For pigs fed the diet with the antibiotic supplementation, the V_max (nmol·mg protein^-1·min^-1) values in the jejunum (38.18 ± 1.22 vs. 27.46 ± 1.96), ileum (28.19 ± 1.61 vs. 20.89 ± 0.86), cecum (3.20 ± 0.24 vs. 3.03 ± 0.26), and colon (12.01 ± 1.18 vs. 9.88 ± 0.85) were increased (P<0.05) by 39.04, 34.94, 5.64 and 21.56%, respectively, compared with the control. These results indicated that dietary antibiotic could mediate improvements in growth rate and gut health status in weanling pigs through increasing intestinal alkaline phosphatase maximal activities.