The Effects Of N-acetylcysteine On Immunological Stress And Energy Status Of Piglets Challenged With Lipopolysaccharide

The aim of the current study was to evaluate effects of dietary supplementation with N-acetylcysteine (NAC) on immunological stress and energy status in piglets after lipopolysaccharide (LPS) challenge. Eighteen healthy piglets (Duroc×Landrace×Large white, 11.58±0.26 kg·BW) were randomly allocated to 3 treatments (control group, LPS group and NAC group). Each treatment included 6 replicates, one piglet per replicate. The piglets in the control and LPS groups were fed with the basal diet, while the NAC group was fed with the basal diet + 500 mg/kg NAC. On d 10, 13 and 20, the piglets in the LPS and NAC groups were injected intraperitoneally with 100μg/kg·BW LPS, and the piglets in the control group were injected intraperitoneally with the same volumn of physiological saline. On d 10 and 20, blood samples were collected from precava vein after 3 h post-injection of LPS or saline. On d 21, all the piglets were sacrificed to collect the samples of gastrocnemius intestinal mucosa and liver, then stored at -80℃for analysis.The results showed that:1. The effects of N-acetylcysteine on muscle energy status in piglets chronically challenged with lipopolysaccharide(1) Dietary supplementation of NAC attenuated the decrease of ATP, total adenine nucleotide (TAN) and energy charge (EC) in gastrocnemius(P<0.05), while attenuated the increase of AMP level and AMP/ATP induced by LPS challenge (P<0.05). (2) Dietary supplementation of NAC attenuated the increase of PAMPK/AMPK in gastrocnemius induced by LPS challenge (P<0.05). (3) Dietary supplementation of NAC attenuated the increase of the expression of HSP70 in gastrocnemius induced by LPS challenge (P<0.05).2. The effects of N-acetylcysteine on intestinal mucosa immunological stress and energy status of piglets chronically challenged with lipopolysaccharide(1) Dietary supplementation of NAC attenuated(P<0.05) the increase of TNF-α, IL-6 and PGE2 in plasma, jejunal, ileal mucosa, and the TNF-αin duodenal mucosa, induced by LPS challenge (P<0.05), trended to attenuate the increase of IL-6 in duodenal mucosa (P<0.1). (2) Dietary supplementation of NAC attenuated the increase of NF-κB in intestinal mucosa induced by LPS challenge (P<0.05). (3) Dietary supplementation of NAC attenuated the increase of the expression of HSP70 in intestinal mucosa induced by LPS challenge (P<0.05). (4) Dietary supplementation of NAC attenuated the decrease of ATP and EC (P<0.05) in intestinal mucosa while attenuated the increase of AMP level and AMP/ATP induced by LPS challenge (P<0.05).3. The effects of N-acetylcysteine on liver immunological stress and energy status of piglets chronically challenged with lipopolysaccharide (1) Dietary supplementation of NAC significantly attenuated the increase of TNF-α, IL-6 and PGE2 in liver (P<0.05). (2) Dietary supplementation of NAC attenuated the increase of the expression of NF-κB and HSP70 in liver induced by LPS challenge (P<0.05). (3) Dietary supplementation of NAC attenuated the decrease of ATP, ADP and EC in liver, while attenuated the increase of AMP level and AMP/ATP induced by LPS challenge significantly (P<0.05).In conclusion, under the present experimental conditions:1. Dietary supplementation with 500 mg/kg NAC could attenuated the increase of AMP level and AMP/ATP, attenuated the decrease of ATP, TAN and EC from LPS challenge, NAC may improve gastrocnemius energy status via inhibiting the phosphorylation of AMPK .2. LPS challenge resulted in intestinal mucosal immunological stress, dietary supplementation with 500 mg/kg NAC attenuated the increase of inflammatory medium in plasma and small intestinal mucosa, alleviated immunological stress, by influencing the NF-κB signaling pathways intestinal mucosa. NAC relieves LPS-induced intestinal mucosa energy depletion via AMPK passway, then play a protective effect on small intestinal mucosa. 3. Dietary supplementation with 500 mg/kg NAC could inhibite increase of inflammatory mediums in plasma and liver, alleviate immunological stress, which possibly via influencing NF-κB expression. Dietary supplementation with 500 mg/kg NAC could exert protective effects on liver by improving the levels of adenine nucleotide.