Effects Of N-Acetylcysteine On Growth Performance And Blood Biochemical Indexes In Piglets Challenged With Lipopolysaccharide

This experiment was to study the effects of N-acetylcysteine (NAC) on growth performance and plasma biochemical indexes in lipopolysaccharide (LPS)-challenged piglets.Twenty-four healthy piglets with the same genetic origin and similar body weight (11.58±0.26 kg) were selected for this 20 days trial, in the initial 10 days (0-10 d), without LPS challenge, the experiment was designed in one factor, 2 dietary treatments (control, 500 mg/kg NAC), each treatment 6 replicates, and two piglets per replicate. In the latter 10 days (10-20 d), one piglet of each replicate was fed alone, and received intraperitoneal administration of LPS on 10, 13 and 20 d, whereas the other one received intraperitoneal administration of the same volume of sterile saline. Average weight was (15.7±0.35) kg when grouping again. Blood samples were collected from precava vein after 3 h post-injection of LPS, plasma biochemical parameters were measured.The measurements and results were as follows:(1) Effects of dietary supplementation with NAC on growth performance in piglets after LPSchallengeAccording to the records of daily feed intake and the body weights on d 1, d 10 and d 20, average daily gain (ADG), average daily feed intake (ADFI) and the ratio of feed to gain (F/G) were calculated. The results indicated that dietary supplementation with 500 mg/kg NAC have no effects on piglets growth performance in the initial 10 days (P>0.05);In the latter 10 days NAC relieved the negative effects on growth performance caused by LPS challenge (P<0.05).(2) Effects of dietary supplementation of NAC on levels of cytokines in piglets challenged with lipopolysaccharideLevels of insulin (INS), insulin-like growth factor-1 (IGF-1) and epidermal growth factor (EGF) in blood samples were assayed with radioimmunoassay. The results indicated that NAC could improve the levels of EGF in blood post-injection on d 10 (P<0.05), while NAC have no effects om the levels of INS or IGF-1 (P>0.05);In the latter 10 days NAC tend to improve the levels of EGF in blood post-injection (P=0.078) , have no effects om the levels of INS or IGF-1 (P>0.05).(3) Effects of NAC on blood biochemical indexes in piglets challenged with lipopolysaccharideBiochemical index in blood samples which collected from precava vein at 3 h post-injection of LPS on 10 and 20 d were assayed. Biochemical indexes included alanine aminotransferase (ALT), aspartate transaminase (AST), total protein (TP), albumin/globulin (A/G), alkaline phosphatase (AKP), and blood urea nitrogen (BUN). The results showed that dietary supplementation with NAC could reduce significantly the plasma level of glutamic-pyruvic transaminase in piglets repeatly challenged with LPS (P<0.05). At day 10, dietary supplementation with NAC for ten days (10 d) tended to increased the levels of plasma alkaline phosphatase (P=0.06), and significantly increased significantly the levels of plasma alkaline phosphatase at day 20 (P<0.05).(4) Effects of NAC on blood anti-oxidation indexes in piglets challenged with lipopolysaccharideAntioxidant index which collected from precava vein at 3 h post-injection of LPS on 10 and 20 d were assayed, antioxidant indexes include glutathione (GSH), malondialdehyde (MDA) and super oxide dismutase (SOD), levels of blood cystine (CYS). The results indicated that when piglets challenged by LPS at day 10, dietary supplementation of NAC increase significantly plasma level of superoxide dismutase (P<0.05); NAC increase the LPS treatmeat plasma level of superoxide dismutase (P=0.07), increase significantly the LPS treatmeat plasma level of glutathione (P<0.05); After piglets repeatly challenged by LPS, dietary supplementation with NAC increase plasma level of glutathione (P<0.01), reduce the plasma level of malonaldehyde (P=0.06), dietary supplementation with NAC have no effects om the levels of blood cystine (P>0.05). The results indicated that dietary supplementation with 500 mg/kg NAC could increase levels of plasma epidermal growth factor, alkaline phosphatase, glutathione and super oxide dismutase, reduce the plasma level of malonaldehyde, improve body anti-oxidant capacity, therefore to relieve the growth depression in weanling piglets challenged by LPS.