Prenatal stress effects on pig development and response to weaning1

Abstract

Exposing a pregnant sow to stress has been shown to affect 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 from an experimentally induced model of prenatal stress. Sow treatments consisted of i.v. injections of ACTH (1 IU/kg of BW), exposure to rough handling for 10 min (Rough), or no treatment (Control) once a week during d 42 to 77 of gestation. To determine the plasma cortisol response to treatments, blood (5 mL) was collected from 30 sows after treatment administration. To conduct the prenatal stress study, a separate group of 56 sows was used in 1 of 4 replicates. At birth, production data were collected for each litter, including birth weight, number born, anogenital distance, and pig viability. At weaning, pigs were blocked by BW and sex, and placed in a nursery pen of 6 pigs, with 2 pigs 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 day for 10 d after weaning. Application of treatments caused plasma cortisol concentrations to be greatest in ACTH sows compared with Control sows (P < 0.001), with Rough sows having intermediate values (P = 0.07). Treatments did not affect the number of pigs born, number of stillborn, or pig viability (P > 0.40). The ratio of cortisol to CBG did not differ between treatments (P = 0.09). Hematological variables did not differ between treatments (P > 0.19). Pigs born to ACTH sows had a smaller anogenital distance compared with controls (P < 0.03), with pigs from Rough sows being intermediate. Our data indicate that swine exposed to prenatal stress (ACTH injection) can have alterations in sexual morphology without effects on growth or the immune cell populations measured in this study.

Growth and reproductive development of male piglets are more vulnerable to midgestation maternal stress than that of female piglets12

“…When the data from male and female piglets were combined for analysis, sow treatment had no effect on any litter or piglet characteristic. This is in accordance with previous research results showing that during midgestation neither the authentic stressors of rough handling (Lay et al, 2008) and mixing (Jarvis et al, 2006;Rutherford et al, 2009), nor the artificial stressors ACTH (Haussmann et al, 2000;Schneider et al, 2004;Brussow et al, 2005;Kanitz et al, 2006;Otten et al, 2007) and HCA (Kranendonk et al, 2006) affected gestation length (Haussmann et al, 2000;Jarvis et al, 2006;Kanitz et al, 2006;Kranendonk et al, 2006;Otten et al, 2007;Lay et al, 2008), litter size (Haussmann et al, 2000;Schneider et al, 2004;Brussow et al, 2005;Kanitz et al, 2006;Kranendonk et al, 2006;Otten et al, 2007;Lay et al, 2008;Rutherford et al, 2009), or number of stillborn pigs (Haussmann et al, 2000;Jarvis et al, 2006;Kranendonk et al, 2006;Otten et al, 2007;Lay et al, 2008).…”

“…In contrast to these results, ACTH injections from GD 42 to 77 reduced anogenital distance in male pigs (Lay et al, 2008) which supports the hypothesis that the ANO lengthening observed in this study was not due to increased GC concentration. Previous research by Ashworth et al (2011) demonstrated that midgestation maternal social stress can influence postnatal testosterone concentration and testicular steroidogenic enzyme expression.…”

“…Fewer male pigs tended to be born to Mixed sows than Companion sows although sex ratio did not differ. Previous research examining midgestation GC administration (Kranendonk et al, 2006;Lay et al, 2008) did not find differences in litter sex structure, thus our results are more likely attributable to components of social stress other than cortisol concentration. However, these results are unlike those from previous research on the effects of midgestation social stress that observed no difference in sex ratio (Jarvis et al, 2006).…”

“…Maternal gestational stress and housing can alter female pigs' puberty (O'Gorman et al, 2007;Estienne and Harper, 2010) and reduce ovarian follicles (Ashworth et al, 2011) and litter size (Jarvis et al, 2006). In male pigs, it can reduce anogenital distance (Lay et al, 2008), a biomarker for fetal androgen exposure during sexual differentiation, and postnatal reproductive hormone concentrations (Ashworth et al, 2011).…”

Pre-natal social stress and post-natal pain affect the developing pig reproductive axis

“…However, Kattesh et al (1979) reported no effects of stressing pregnant sows with heat and crowding for 50 days during mid-pregnancy on testosterone concentrations or libido of male offspring. Shorter anogenital distances in male offspring have been observed in prenatally stressed male rats (Williams et al 1998, Mairesse et al 2007) and in male pigs born to sows receiving weekly injections of ACTH during mid-pregnancy (Lay et al 2008).…”