Authors : Changhua Lai , Jindong Yin , Defa Li , Lidan Zhao and Xingjie Chen
Abstract: Seventy-two crossbred (Large White x Landrace x Pietrain) pigs weaned at 28 days of age (8.12 kg BW) were used to investigate the effects of dietary conjugated linoleic acid (CLA) on performance and immunological responses of pigs after lipopolysaccharide (LPS) challenge in a 2 ? 2 factorial design experiment. The main factors consisted of diet (2% CLA vs. 2% soybean oil) and immune challenge (LPS vs. saline). On d 14 and 21, pigs were injected intraperitoneally with either LPS (100 ?g/kg BW) or sterile saline. From d 14 to 28, LPS challenge decreased ADG and ADFI (P<0.01), while CLA improved ADG (P=0.05) and feed efficiency (P<0.05) compared with soybean oil. From d 14 to 28, an LPS challenge ? diet interaction was observed for ADG (P=0.05) in which the depression due to LPS challenge was alleviated by feeding CLA. An LPS challenge ? diet interaction (P=0.05) was observed for TNF- and -AGP such that they responded to the LPS challenge to a lesser extent in CLA-fed pigs than in soybean oil-fed pigs. On d 14 and 21, LPS-treated pigs had higher (P<0.01) plasma cortisol compared with saline-injected pigs, whereas CLA-fed pigs had lower cortisol (P=0.10) relative to soybean oil-fed pigs. On d 15 and 22, LPS increased peripheral blood lymphocytes proliferation, CD4+ and CD8+ lymphocyte subsets (P< 0.05). CLA enhanced CD8+ lymphocyte subsets (P < 0.05) and decreased the CD4+/CD8+ ratio (P < 0.05). These results indicate that CLA improves immunity and alleviates the growth depression induced by immune challenge by inhibiting the production of TNF- and -AGP.
Changhua Lai , Jindong Yin , Defa Li , Lidan Zhao and Xingjie Chen , 2005. Effects of Dietary Conjugated Linoleic Acid Supplementation on the Performance and Immunological Responses of Weaned Pigs After an Escherichia coli Lipopolysaccharide Challenge . Journal of Animal and Veterinary Advances, 4: 299-305.