Publications (37) View all
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Article: Effect of prenatal stress on subsequent response to mixing stress and a lipopolysaccharide challenge in pigs.
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ABSTRACT: Sows subjected to prenatal stress have been found to produce offspring that have altered responses to stress. Our objective was to determine if exposing a sow to stress would alter the response of the offspring to lipopolysaccharide (LPS) at 2 mo of age or their response to mixing stress at 4 mo of age. Sow treatments consisted of intravenous injections of ACTH (1 IU/kg of BW), exposure to rough handling for a 10-min duration (rough), or no treatment (control) once per week from d 42 to 77 of gestation. At 2 mo of age, pigs from each treatment, 1 per litter (n = 21, 17, and 15 for the ACTH, rough, and control treatments, respectively), were challenged with 2 μg of LPS/kg of BW or saline, or served as a noninjected control. Their behavioral response to a human approach test and salivary cortisol were measured. At 4 mo of age, 1 pig from each treatment (n = 14, 14, and 15 for the ACTH, rough, and control treatments, respectively) was taken from its home pen and placed in a pen of unfamiliar pigs. At this time, a punch biopsy wound (6 × 6 mm) was created to measure the ability of the pig to heal the wound. At this same time, each pig received a 1-mL intramuscular injection of 20% ovine red blood cells (oRBC), and then a second injection of oRBC at 21 d postmixing. Blood samples were collected 3 times per week for 2 wk and then once a week for 4 more weeks. Blood samples were analyzed for cortisol, porcine corticosteroid-binding globulin, antibody response to oRBC, and nitric oxide production by macrophages. Behavior was recorded during the first 5 d after mixing. All pigs in the LPS challenge responded with characteristic sickness behavior; however, pigs in the rough treatment showed less sickness behavior than those in the other 2 treatments (P < 0.05). Maternal stress treatment did not affect (P < 0.43) salivary cortisol. Pigs from all treatments responded similarly to mixing stress with regard to cortisol, porcine corticosteroid-binding globulin, antibody titers, nitric oxide production, and hematology measures, and all pigs experienced the same amount of aggression in response to mixing. Without altering peripheral measures of stress responsivity, prenatal stress enhanced the ability of pigs to cope with a simulated immune challenge, which could prove to be an adaptation to challenging environments.Journal of Animal Science 06/2011; 89(6):1787-94. · 2.10 Impact Factor -
Article: Effects of weaning and syndyphalin-33 on expression of melanocortinergic appetite-regulating genes in swine.
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ABSTRACT: Syndyphalin-33 (SD-33) increases feed intake in sheep and recently weaned pigs. To assess the effects of SD-33 on hypothalamic gene expression, hypothalami were collected from unweaned pigs (n=19; 21±3 d of age) on day 0. Remaining pigs received an intramuscular injection of 0.5 μmole/kg SD-33 (SD) or saline (VEH) and weaned into individual pens. On days 1, 4, and 7 after weaning, hypothalami were collected from subsets of pigs (n=8 or 9) within each treatment group. Expression of μ-opioid receptor (MOR) was less in SD pigs than in VEH pigs on day 1 and day 4, suggesting down-regulation of the receptor by SD-33. Expression of hypothalamic melanocortin 4 receptor (MC4R) at 1 d after weaning was increased in VEH pigs (but not SD pigs) relative to levels before weaning. Expression of AGRP was not significantly altered by weaning or treatment at 1 d after weaning. At 4 d after weaning, expression of AGRP was greater in SD pigs than in VEH pigs, but at day 7 expression was less in SD pigs than in VEH pigs. A strong positive correlation was noted between expression levels of MOR and MC4R across treatment and time. Treatment with SD-33 appeared to partially abrogate the effects of weaning on expression of two key appetite-regulating genes within 24 h. Effects of SD-33 appear to be mediated at least in part by the μ-opioid receptor and include actions on the melanocortinergic pathway.Domestic animal endocrinology 12/2010; 40(3):165-72. · 1.65 Impact Factor -
Article: Effects of syndyphalin-33 on feed intake and circulating measures of growth hormone, cortisol, and immune cell populations in the recently weaned pig.
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ABSTRACT: The synthetic met-enkephalin syndyphalin-33 (SD-33) increases feed intake in sheep and transiently increases circulating GH concentrations in sheep, rats, and pigs. Two experiments were performed to evaluate the effects of SD-33 on recently weaned pigs. In a preliminary experiment, pigs were administered SD-33 (0.5 micromol/kg, given intramuscularly) or saline immediately before a 3-h transport and subsequent placement into group pens. Treatment with SD-33 increased (P = 0.01) daily feed intake; cumulatively, pen intake over 7 d postweaning tended (P = 0.06) to be greater than in control pens. In Exp. 2, pigs were weaned and fitted with jugular catheters. The following day, pigs were treated with SD-33 or saline as described above. Transient increases (P < 0.05) in circulating concentrations of GH (at 1 and 1.5 h postinjection) and cortisol (at 3.5 and 4 h postinjection) were observed in pigs treated with SD-33 relative to controls. No difference in feed intake was observed between treatments over 4 d postinjection. Increased (P < 0.05) numbers of circulating neutrophils, lymphocytes, and monocytes were observed in both treatment groups over 4 d postinjection, and treatment with SD-33 tended (P = 0.07) to selectively increase monocyte numbers. Although SD-33 has potential to be used to increase feed intake and decrease the negative effects of stress during weaning in pigs, further investigation is needed to better understand the timing of effect and to rule out possible immunosuppressive effects.Journal of Animal Science 06/2009; 87(10):3218-25. · 2.10 Impact Factor -
Article: Effects of Transport Stress, Sex, and Weaning Weight on Postweaning Performance in Pigs
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ABSTRACT: To examine the effects of transport, sex, and weaning weight on postwean-ing performance, pigs were weighed and blood was collected immediately before weaning (d 0; with or without a 3-h transport) and on d 1 and 7 postweaning. Corticosteroid-binding globulin concen-trations decreased by d 1 and remained suppressed through d 7 regardless of transport. Cortisol concentrations in males increased from d 0 to 1 and then decreased to preweaning levels by d 7; females had higher preweaning cortisol levels that did not change on d 1 but that decreased by d 7 to lower levels than in males. The free cortisol index was elevated on d 1 in all groups but returned to preweaning levels by d 7. Low wean-ing weight was associated with lower corticosteroid-binding globulin concentra-tions and higher free cortisol index on d 1. White blood cell counts increased from d 0 to 1, and then decreased by d 7. The percentage and number of neutrophils as well as the neutrophil:lymphocyte ratio followed a similar pattern. Females had higher numbers of neutrophils than males on d 1. Low weaning weight was associ-ated with greater numbers and percentag-es of neutrophils before weaning, but not after; weaning appeared to uncouple the relationship between BW and circulat-ing immune cell populations. The stress caused by weaning was greater than that associated with transport and was, in part, related to weaning weight. Under-standing how factors influence postwean-ing performance will yield new strate-gies to reduce their effects and increase uniform and efficient growth.The Professional Animal Scientist. 01/2009; 25:189-194. -
Article: Relationships Between Plasma Cortisol, Corticosteroid-binding Globulin (CBG) and The Free Cortisol Index (FCI) In Pigs Over A 24 h Period
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ABSTRACT: The relationship between plasma free cortisol and the free cortisol index (FCI, the ratio of cortisol to CBG) was evaluated in eight 8-wk old pigs over a 24 h period and in response to administration of saline or ACTH. A high (p<0.001) correlation was found between actual free cortisol and the FCI in both saline (r = 0.73) and ACTH (r = 0.85) treated pigs. A diurnal rhythm was apparent for total cortisol, free cortisol, percent free cortisol, pCBG and the FCI. Total cortisol (p<0.05), free cortisol (p<0.05) and the FCI (p<0.01) were elevated during the first four h following administration of ACTH. Concentrations of pCBG differed (p<0.001) over time and were higher (p<0.01) for ACTH treated pigs over the 24 h period. The results from this study affirm the contention that FCI is a suitable estimate of free cortisol in swine.Journal of Animal and Veterinary Advances. 01/2006;
