298 Effect of dietary S-abscisic Acid (S-ABA) supplementation on the growth performance and antioxidant status of nursery pigs.

Abstract To evaluate the effect of dietary S-abscisic acid (S-ABA) supplementation on the growth performance and antioxidant status, 320 nursery pigs (DNA 241 × 600; initially 5.4 ± 0.51 kg) were weaned at approximately 18 d of age and assigned to pens in a generalized randomized block design with gender and weight category as blocking factors. Pigs were fed a common phase 1 diet from weaning to day 8. On day 8 post-weaning (considered d 0 of the study), pens of pigs (6.4 ± 0.57 kg) within gender × weight blocks were randomly allotted to 1 of 4 dietary treatments. Treatments included a conventional nursery diet (Control) and 3 diets which used the Control formulation with increasing S-ABA (0.5, 1.0 and 5.0 mg/kg. Treatments were provided during phases 2 (d 0 to 14) and 3 (d 14 to 35). Growth performance was measured weekly. Additionally, blood samples were collected from 32 pigs on d 0 and 2 pigs per pen on d 14 and 35 to assess the erythrocytes’ total glutathione (GSH+GSSG), reduced glutathione (GSH), oxidized to reduced glutathione ratio (GSSG:GSH), serum total antioxidant capacity (TAC), superoxide dismutase (SOD), and thiobarbituric acid reactive substances (TBARS). At the termination of the trial, 2 pigs in each pen were euthanized and duodenal, jejunal, and ileal mucosa were collected to measure GSH+GSSG, GSH, and GSSG:GSH. No interactive effect on growth performance between S-ABA and gender was observed throughout the study. There was also no interaction between S-ABA and collection day on antioxidant parameters. Increasing S-ABA did not influence growth performance. Erythrocyte GSH+GSSG tended to increase (linear, P = 0.056) with increasing S-ABA on d 14, while GSH showed a similar trend on d 14 (linear, P = 0.096) and d 35 (quadratic, P = 0.100). The d 35 GSSG:GSH ratio decreased (quadratic, P = 0.022) with increasing S-ABA. Serum TAC, SOD, and TBARS were not influenced by S-ABA. Similarly, dietary S-ABA had no effect on GSH+GSSG, GSH, and GSSG:GSH in the intestinal mucosa. In conclusion, dietary addition of S-ABA improved the antioxidant status of nursery pigs by reducing the erythrocyte GSSG:GSH ratio without negative effects on growth performance.