Abstract
We recently showed that functional amino acid (FAA) supplementation improves growth performance and immune status of Salmonella Typhimurium (ST)-challenged pigs which was further improved by a longer adaptation period. It is expected that the effects are associated with increased activity of intestinal alkaline phosphatase (IAP). The objective of this study was to evaluate the effects of FAA supplementation and adaptation period on the ileal, cecal, and colonic activity of IAP in weaned pigs challenged with ST. In Exp. 1, 32 mixed-sex weanling pigs were randomly assigned to dietary treatments in a 2 × 2 factorial arrangement with low (LP) or high protein (HP) content and basal (FAA–) or FAA profile (FAA+; Thr, Met, and Trp at 120% of requirements) as factors. In Exp. 2, a total of 32 mixed-sex weanling pigs were randomly assigned to 1 of 4 dietary treatments, being FAA- fed throughout the experimental period (FAA−) or a FAA profile fed only in the post-inoculation (FAA+0), for 1 wk pre- and post-inoculation (FAA+1), or throughout the experimental period (FAA+2). In Exp. 1 and 2, after a 7- and 14-d adaptation period, respectively, pigs were inoculated with saline solution containing ST (3.3 and 2.2 × 10 9 CFU/mL, respectively). Plasma alkaline phosphatase was measured on d 0 and 7 post-inoculation in Exp. 1, and IAP (ileum, cecum, and colon) was measured in Exp. 1 and 2. Correlations among ileal IAP and serum albumin and haptoglobin, plasma superoxide dismutase (SOD), malondialdehyde (MDA), and reduced:oxidized glutathione (GSH:GSSG), ileal myeloperoxidase (MPO), ST shedding and ileal colonization, and post-inoculation average daily gain (ADG), feed intake (ADFI), and gain:feed (G:F) were also analyzed. In Exp. 1, plasma alkaline phosphatase was decreased with ST inoculation and overall content was increased in LP-FAA+ compared to LP-FAA- (P < 0.05). Moreover, ileal IAP was increased in FAA+ compared to FAA- pigs in both studies (P < 0.05) regardless of adaptation time (P > 0.05). Intestinal alkaline phosphatase was positively correlated with MDA and ADFI and negatively correlated with SOD and ST shedding in Exp. 1 (P < 0.05). These results demonstrate a positive effect of FAA supplementation, but not adaptation period, on ileal alkaline phosphatase activity in Salmonella-challenged pigs, which may be associated with improvements in antioxidant balance.
PLASMA ALKALINE PHOSPHATASE VALUES IN WEANLING PIGS AS INFLUENCED BY DIETARY CALCIUM : PHOSPHORUS RATIO AND CESTRUM DIURNUM INGESTION
