The aim of the current study was to evaluate the effects of dietary supplementation with N-acetylcysteine(NAC)on liver immunological stress and energy status in piglets after lipopolysaccharide (LPS) challenge. Eighteen healthy piglets with the same genetic origin and similar body weight (Duroc ×Landrace × Large white, (11. 58 ± 0. 26) kg BW) were randomly allocated into 3 treatments (control group, LPS group and NAC group). Each treatment included 6 replicates, one piglet per replicate. The piglets in the control group and LPS group were fed with the basal diet, while the NAC group was fed with the basal diet + 500 mg · kg-1 NAC. On dl0, dl3 and d20, the piglets in the LPS and NAC groups were injected intraperitoneally with 100 μg · kg-1 BW LPS, and the piglets in the control group were injected intraperitoneally with the same dose of physiological saline. On dlO and d20, blood samples were collected from precava vein after 3 h post-injection of LPS. On d21, all the piglets were sacrificed to collect liver for a-nalysis. The results showed that: (1) Dietary supplementation of NAC attenuated the decrease of F/G (P<0. 05)and the increase of ADG(P<0. 05). (2) Dietary supplementation of NAC significantly attenuated the increase of TNF-α> IL-6 and PGE2 in plasma and liver(P<0. 05). (3) Dietary supplementation of NAC attenuated the increase of the expression of NF-ΚB and HSP70 induced by LPS challenge (P<0. 05). (4) Dietary supplementation of NAC attenuated the decrease of ATP, ADP and energy charge (EC), while attenuated the increase of AMP level and AMP/ ATP induced by LPS challenge significantly (P<0. 05). These results indicated, under the present experimental conditions, dietary supplementation with 500 mg · kg-1 NAC could significantly improve growth performance via ameliorating the immunological stress and energy depletion in piglets challenged with LPS.%本研究旨在N-乙酰半胱氨酸(NAC)对脂多糖(LPS)刺激仔猪肝脏免疫应激和能量状况的影响及其机理进行探讨.选取18头健康仔猪(杜洛克×长白×大白,体质量(11.58±0.26)kg),随机分成3个处理(对照组、LPS组和NAC组),每个处理6个重复,每个重复1头猪.对照组和LPS组饲喂基础日粮,NAC组饲喂基础日粮+500 mg·kg-1 NAC,LPS和NAC组仔猪分别于试验的第10、13、20天腹膜注射100 μg·kg-1 BW的LPS,对照组注射等量的灭菌生理盐水.第10、20天注射LPS后3h前腔静脉采血,第21天仔猪麻醉后进行屠宰,取肝脏样品待测.试验结果显示:(1)日粮中添加NAC显著缓解了LPS刺激导致的ADG降低(P＜0.05)和F/G的升高(P ＜0.05).(2)日粮中添加NAC缓解了LPS刺激导致的血浆、肝脏中TNF-α、IL-6和PGE2的升高(P＜0.05).(3)日粮中添加NAC缓解了LPS刺激导致的肝脏核因子-κB(NF-κB)和热休克蛋白70 (HSP70)蛋白表达量的升高(P＜0.05).(4)日粮中添加NAC缓解了LPS刺激导致的肝脏中三磷酸腺苷(ATP)、二磷酸腺昔(ADP)和能荷(EC)水平的降低(P＜0.05)及一磷酸腺苷(AMP)水平和AMP/ATP比值的升高(P＜0.05).由此可见,日粮中添加500 mg·kg-1 NAC可能通过缓解LPS导致的免疫应激和能量的过度损耗,促进仔猪生长.
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