|Lay, Jr, Donald - Don|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/12/2008
Publication Date: 2/13/2008
Citation: Lay Jr, D.C., Kattesh, H.G., Cunnick, J.E., Daniels, M.J., McMunn, K.A., Toscano, M.J., Roberts, M.P. 2008. Prenatal stress on pig development and response to weaning. Journal of Animal Science. 86:1316-1324. Interpretive Summary: Prenatal stress, the stress imposed on a pregnant dam that may influence her subsequent offspring, has been shown to have profound effects on behavior and physiology of many species, including monkeys, rats, guinea pigs, goats, humans and swine. Research in our laboratory has shown that prenatal stress, from restraint, or a stress hormone injection of the sow, caused offspring to have altered neurohormones and adrenal gland morphology, greater plasma cortisol in response to stress and less ability to heal a wound. Prenatal stress has been shown to impair the immune function, increase the maximum binding capacity of glucocorticoids receptors in the central nervous system immediately after birth, and cause an increase in fetal cortisol which may be the mechanism by which prenatal stress causes its effects. The phenomena of prenatal stress demands our complete understanding in order to optimize both welfare and productivity in farm animals due to the fact that prenatal stress can affect both the physiology and behavior of animals, in a wide array of species. To further explore the phenomena of prenatal stress and its effects in swine, we subjected gestating sows to injections of a stress hormone, or we subjected sows to rough handling during gestation. Our data indicate that stress during gestation alters the physiology of a sow’s subsequent offspring. Some housing environments are known to be stressful and in group housed sows, individuals that reside on the bottom of the hierarchy also could be producing litters of prenatally stressed piglets. This project has shown that prenatal stress in swine is likely caused not by cortisol alone but by other factors as well. This finding agrees with that in other species. Our data indicate that swine, exposed to pre-natal stress, can have alterations in sexual morphology and hypothalamic-pituitary-adrenal function; but with little effect on growth or immune function. These findings will aid scientists in understanding the implications of prenatal stress and it identifies possible mechanisms of action.
Technical Abstract: Exposing a pregnant sow to stress has been shown to have negative effects on the resulting offspring. Our objective was to determine if rough handling of pregnant sows altered the physiology of her offspring, and if these alterations were different then an experimentally induced model of prenatal stress. Sow treatments consisted of i.v. injections of adrenocorticotrophin (ACTH, 1 IU/kg BW) (ACTH), exposure to rough handling for a 10-min duration (Rough), or no treatment (Control) once a week during d 42 to 77 of gestation. To determine the plasma cortisol response to treatments, blood was collected from 30 sows after treatment administration. To conduct the prenatal stress study, a separate group of 64 sows were used in one of four replicates. At birth, production data were collected for each litter, including birth weight, number born, ano-genital distance, and piglet viability. At weaning piglets were blocked for weight and sex, and placed in a nursery pen of six piglets with 2 piglets from each treatment group. To assess the effect of treatments on cortisol, corticosteroid-binding globulin (CBG) and hematological cell profiles, blood was collected every other d for 10 d after weaning. Application of treatments caused plasma cortisol to be greatest in ACTH sows compared to Control sows (P < .0001) with Rough sows having intermediate values (P < .001). Treatments did not affect the number of piglets born, number of still born, or piglet viability (P > .40). Piglets born to Rough sows had a lower cortisol/CBG ratio on d 2 after weaning compared to the piglets from ACTH and Control sows (P < .05). Lymphocyte and monocytes were lower in piglets from Control sows as compared to piglets from ACTH sows (P < .008) but only tended to be lower than piglets from Rough sows (P < .07). Piglets born to ACTH sows had a smaller anogenital distance compared to controls (P < .03), with piglets from Rough sows being intermediate. Our data indicate that swine, exposed to pre-natal stress, can have alterations in sexual morphology and hypothalamic-pituitary-adrenal function; but with little effect on growth or immune function.