|Maddock, Kasey - ANIMAL SCIENCE-UNIV OF MO|
|Berg, Eric - ANIMAL SCIENCE-UNIV OF MO|
Submitted to: Journal of Animal and Veterinary Advances
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 2003
Publication Date: October 15, 2003
Citation: MADDOCK, K.R., CARROLL, J.A., BERG, E.P. EVALUATION OF THE POTENTIAL ROLE OF ALPHA-LIPOIC ACID WITH REGARD TO HEALTH AND PERFORMANCE OF WEANLING PIGS. JOURNAL OF ANIMAL AND VETERINARY ADVANCES. 2003. V. 2(10). P. 554-563. Interpretive Summary: A study was conducted to evaluate the potential of alpha-lipoic acid as an immunomodulatory supplement in weaned pigs. Pigs were supplemented with lipoic acid for 12 days, and then immune challenged with lipopolysaccharide (LPS), the toxic component of the cell wall from gram-negative bacteria. Blood and tissue samples were collected after the LPS challenge to evaluate the magnitude of the stress and immune responses in the pigs. Blood analysis revealed concentrations of many hormones increased after LPS administration and some relationships existed between concentrations of these hormones and supplementation of lipoic acid. However, these relationships were not consistent, and may reflect a need for either higher doses of lipoic acid and/or supplementing with lipoic acid for a longer duration in order to see any beneficial effects. These data do, however, provide insight into the ability of lipoic acid to modulate immune system function in weaned pigs. Further studies are warranted into the immunomodulatory properties of lipoic acid in weanling pigs. These data may be useful to immunologists and stress physiologists to enhance the understanding of how nontraditional antioxidants can be incorporated into livestock production to provide immunological protection.
Technical Abstract: Objectives of this study were to: 1) determine the affect of supplemental lipoic acid (LA) on feed conversion and rate of gain on weanling pigs and 2) to evaluate the potential immunological benefits of supplementing piglet starter diets with lipoic acid. Twenty-one weaned gilts (d 21, 7 kg) were randomly allotted to three treatment groups: 1) Control, no supplemental LA (n = 7); 2) LA-8, orally supplemented with 8 mg/kg body weight of LA per day (n = 7); and 3) LA-15, orally supplemented with 15 mg/kg body weight of LA per day (n = 7). Pigs were individually penned and treatments were administered orally for 12 days. Feed intake and body weights were recorded from d 0 to d 12. On d 11, pigs were nonsurgically fitted with jugular cannulae. On d 12, all pigs received a dose of 150 ug/kg of lipopolysaccharide (LPS). Blood samples were collected at 15 min intervals for 30 min prior to the LPS challenge and for 180 min after LPS challenge to monitor serum cortisol, tumor necrosis factor-alpha (TNF-alpha), glucose, and insulin. Additional whole-blood samples were collected to determine total neutrophils and lymphocytes, as well as percentages. After the last blood sample was collected, all pigs were sacrificed for the collection of muscle and liver samples. Orally supplemented LA had no effect (P > 0.05) on average daily gain, average daily feed intake, or gain-to-feed ratios. No effect of LA was seen throughout the LPS challenge period (P > 0.05) on serum cortisol or TNF-alpha concentrations. For serum glucose concentrations, differences among treatments were observed at '30 min pre-LPS such that serum glucose was lower (P < 0.05) in the LA-8 and LA-15 groups when compared to the LA-0 group. An LA treatment effect (P < 0.05) was observed between 45 and 165 min post-LPS, where LA-8 had higher serum glucose when compared to the LA-0 and LA-15 groups. From 120 until 165 min post-LPS, both LA-8 and LA-15 had higher serum glucose when compared to the LA-0 group (P < 0.05). Serum insulin concentrations did not differ (P > 0.05) among groups due to LA supplementation. There was a trend (P < 0.15) for the LA-15 group to have lower glycogen content in the muscle samples when compared to the LA-0 and LA-8 groups. Glycogen content in the liver was lower in the LA-0 group when compared to the LA-8 group. On d 12, prior to the LPS challenge, the percentage of neutrophils was greater and the percentage of lymphocytes was lower (P < 0.05) in the LA-15 group when compared to the LA-0 and LA-8 groups. Further research is needed to determine whether supplemental LA may be utilized as a beneficial immunomodulator in swine.