|Carroll, Jeffery - Jeff Carroll|
Submitted to: Domestic Animal Endocrinology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2008
Publication Date: 3/20/2008
Citation: Daniel, J., Carroll, J.A., Keisler, D., Kojima, C. 2008. Evaluation of immune system function in neonatal pigs born vaginally or by Cesarean section. Domestic Animal Endocrinology. 35(1):81-87.
Interpretive Summary: In previous research, we reported that pigs born by C-section have elevated basal cortisol, a stress related hormone, relative to vaginal birth pigs at 2 weeks of age. We have also demonstrated that pigs born by C-section have reduced growth rates and reduced circulating concentrations of insulin-like growth factor-I despite having elevated circulating concentrations of growth hormone compared to vaginally delivered pigs. Therefore, the present study was designed to determine if type of birth influences subsequent development and/or function of the immune system in neonatal pigs. Specifically, we examined basal concentrations and endotoxin-stimulated concentrations of proinflammatory cytokines, as well as selected gene expression in various tissues, associated with the acute phase immune response in pigs born by vaginal birth or by C-section. For this study, we used eight full term crossbred sows to study of the interactions of the immune system, stress axis, and growth in pigs born by C-section or vaginal-birth (n=4 each for vaginal-birth and C-section). Gestation length and birth weight did not differ between vaginal-birth and C-section pigs. Blood and tissue samples were collected from 44 pigs at birth. Forty-five pigs were weaned at 13 days of age and fitted with an indwelling jugular cannula for blood sample collection at 14 days of age. Results from our study suggest that altered immune system function may be partially responsible for the reduction in growth observed in C-section compared to vaginally delivered pigs. Expression of proinflammatory cytokines and associated receptors appear to be controlled in an age and tissue specific manner in the neonatal pig. The possibility that the type of birth delivery may alter the function of the immune system is an important consideration for animals born by C-section. Further research is warranted to determine if type of birth negatively affects the future development and function of the immune system, and if any effect is detrimental to the animal’s overall health.
Technical Abstract: Eight full term crossbred sows were selected for study of the interaction of the immune system, hypothalamus-pituitary-adrenal axis, and growth in pigs born by Cesarean section (C-section) or vaginal-birth (n=4 each for vaginal-birth and C-section). Gestation length and birth weight did not differ between vaginal-birth and C-section pigs (P=0.34 and 0.62, respectively). Blood and tissue samples were collected from 44 pigs at birth. Forty-five pigs were weaned at 13 days of age and fitted with an indwelling jugular cannula for blood sample collection at 14 days of age. Pigs received an intra-peritoneal injection of lipopolysaccaride (LPS; 150 micrograms per kilogram) or saline at min 0, blood samples were collected at -20, -10, 0, 5, 10, 20, 40, 60, 90 and 120 minutes. Tissue samples were collected immediately following the 120 minute sample. Vaginal-birth pigs had 21% greater average daily gain than c-section pigs (P<0.01). Basal serum adrenocorticotrophin (ACTH) and cortisol was greater in C-section than vaginal-birth pigs at birth (P<0.01) but was not different at 14 days of age (P=0.99 and 0.80, respectively). Serum ACTH, cortisol, interferon-gamma (INF-gamma), and tumor necrosis factor-alpha (TNF-alpha) increased in response to LPS challenge (P<0.01) but the response was not different between C-section and vaginal-birth (P>0.22). Basal serum TNF-alpha tended to be greater in C-section versus vaginal-birth pigs at 14 days of age (P=0.0967). Basal serum IFN-gamma tended to be lower in C-section pigs versus vaginal-birth pigs at 14 days of age (P=0.0787). Collectively, these data suggest reduced growth rate of C-section pigs may be result from altered immune system function.