Effects of in vitro adrenocorticotrophic hormone, cortisol and human recombinant interleukin-2 on porcine neutrophil migration and luminol-dependent chemiluminescence

Assessing the effects of ex vivo hormonal exposure on oxidative responses in equine leukocytes: A preliminary study

Breed differences exist between horses and ponies in circulating concentrations of several hormones, notably ACTH and insulin. These hormones regulate stress and metabolic responses, but in other species, they also impact leukocyte oxidant responses. The effects of these hormones on equine leukocytes have not been evaluated to date. If equine leukocytes are similarly regulated, breed differences in increased plasma hormone concentrations or altered sensitivity to them at the leukocyte level could result in breed-related differences in oxidant responses or oxidative status. The objective of this study was therefore to determine the effects of ex vivo exposure to adrenocorticotropic hormone (ACTH), α-melanocyte stimulating hormone (α-MSH), insulin, or leptin on reactive oxygen species (ROS) production from leukocytes isolated from horses and ponies. We hypothesized that ACTH, α-MSH, insulin, and leptin would alter oxidant responses from equine leukocytes in a breed specific manner. Blood was collected from 10 apparently healthy Quarter horses and seven Welsh ponies for isolation of neutrophils and peripheral blood mononuclear cells (PBMCs) via density gradient centrifugation. Cells were incubated with media (negative control), microbial antigens (positive control), or ACTH, α-MSH, leptin, or insulin for two hours. Induced ROS production was quantified with a previously validated fluorometric assay. Data was compared within groups by comparing a stimulant within a group (horses or ponies) to baseline, between groups by comparing horse response to pony response, and among stimulants using one- and two-way, repeated measures ANOVA (P<0.05). There was no significant effect of breed on basal, microbial-induced, or hormone-induced ROS production from neutrophils (P=0.465) or PBMCs (P=0.749), but in neutrophils, a significant interaction between breed and stimulant was present (P=0.037). ROS production from PBMCs from horses after hormone exposure did not differ from cells exposed to media only (P=0.1520-0.8180). Similarly, neither leptin nor insulin exposure significantly induced ROS production from PBMCs from ponies (P= 0.2645 and 0.4678 respectively), but exposure to ACTH or α-MSH induced a significant increase in ROS production (P=0.0441 and 0.0440 respectively) compared to unstimulated cells. Hormones that vary in availability among breeds may induce ex vivo pro-oxidant responses in equine leukocytes, but specific effects are breed-, leukocyte type-, and hormone-dependent. Breed differences in hormonally induced leukocyte ROS production may warrant further investigation in the context of circulating oxidative stress and how this might relate to future disease risk.

Grass carp Il-2 promotes neutrophil extracellular traps formation via inducing ROS production and autophagy in vitro

Interleukin (IL)-2 has been reported to regulate neutrophil functions in humans, mice, pigs and chicken although it is a key regulator of T cells. Consistently, we found that grass carp (Ctenopharyngodon idellus) interleukin-2 (gcIl-2) is capable of modulating the antimicrobial activities of neutrophils via regulating granzyme B- and perforin-like gene expression in our previous study. In the present study, stimulation of gcIl-2 on neutrophil extracellular traps (NETs) formation in grass carp neutrophils was demonstrated by detecting free DNA release, histone H3 citrullination and morphological changes of the cells. Further investigation revealed that reactive oxygen species (ROS) production from NADPH oxidase but not mitochondria was involved in NETosis induced by gcIl-2. Aside from ROS, autophagy was disclosed to be indispensable for NETosis induced by gcIl-2. These converging lines of evidence suggested that fish Il-2 could induce NETs formation via NADPH oxidase-derived ROS- and autophagy-dependent pathways in fish species which is evolutionarily conserved with that in mammals. It is noteworthy that these two pathways did not interplay with each other in Il-2-stimulated NETosis. The mechanisms governing autophagy induced by Il-2 were also explored in the present study, showing that Il-2 modulated the action of high mobility group box 1 (HMGB1) protein to stimulate autophagy, leading to NETs formation in fish neutrophils. These results provided a new insight to the function of Il-2 in fish neutrophils, and a clue about the regulation of NETosis in the lower vertebrates.

Immune phenotype is differentially affected by changing the type of bovine respiratory disease vaccine administered at revaccination in beef heifers

During preconditioning, modified-live vaccines are frequently administered to beef calves before weaning. In this study, we began to characterize the immune phenotype of calves that received a modified-live vaccination at 3-4 months of age and then either received the same modified-live or an inactivated vaccine upon arrival at the feedlot (weaning) and 28 days post-arrival (booster). Innate and adaptive immune measures were assessed before revaccination and 14 and 28 days post. Heifers that received three doses of the modified-live vaccine exhibited a relatively balanced immune response based on increases in mean cytokine concentrations (IL-17, IL-21) and total immunoglobulin-G (IgG) and subsets IgG1 and IgG2, which are related to both arms of the adaptive immune system. Conversely, heifers that received one dose of modified live and two doses of the inactivated vaccine had a more robust neutrophil chemotactic response and greater serum-neutralizing antibody titers, resulting in an enhanced innate immune and a skewed proinflammatory response. These results indicate that the revaccination protocol used after initial vaccination with a modified-live vaccine differentially influences the immune phenotype of beef calves, with three doses of modified live inducing potentially immune homeostasis and a combination of modified live and inactivated vaccines inducing a skewed immune phenotype. However, more research is needed to determine the protective efficacy of these vaccination protocols against disease.

Maternal Supplementation of Saccharomyces cerevisiae boulardii during Late-Gestation through Lactation Differentially Modulated Immune Status and Stress Responsiveness of the Progeny to Farrowing and Weaning Stressors

Simple Summary

The present study offers insights into the prenatal and postnatal maternal effects of feeding probiotics to pregnant sows from late-gestation through lactation on progeny immune status and stress responsiveness at birth, suckling, and through 14 days post-weaning. These results provide evidence that the neonate’s immune system and stress responsiveness can be modulated in utero by feeding sows probiotics during gestation. Some immune parameters are also affected through the suckling period. Moreover, the progeny’s immune status and cortisol profiles were differentially affected by weaning stress, and these effects were apparent up to 14-days post-weaning. These results suggest that it is plausible to affect the progeny’s immune status and stress responsiveness in response via feeding the sow probiotics for 60 days.

Abstract

The study aimed to investigate and characterize the maternal effects of feeding Saccharomyces cerevisiae var. boularddii (Scb) to sows from late-gestation through lactation on progeny cortisol, immune status, and stress responsiveness from birth to 14 days post-weaning. Eighty-four piglets were born to sows fed control (CON) or probiotic (PRO) boluses twice daily for 59 days. Blood samples were obtained at birth and 24 h later to assess prenatal effects; 7, 14, and 21 day-of-age to assess potential developmental effects; and at 24 h, 7, and 14 days post-weaning to assess the effects of weaning stress on immune and cortisol responses. Pigs born to PRO sows had less robust cortisol response and enhanced immune parameters at birth and 24 h later, indicating less stress. In response to weaning, pigs born to and nursed by PRO sows displayed unique cortisol and immune profiles than CON pigs. These results indicate that feeding sows Scb probiotics during late gestation reduces stress responsiveness to farrowing stress while increasing immune cell populations. Pigs nursed by PRO sows had a more robust initial cortisol response and enhanced neutrophil function and B-cell lymphocyte proliferation in response to weaning stress. These data imply it may be possible to maternally alter immune and stress responses in utero and during suckling in the short-term and up to 14 days post-weaning. However, more research is needed to optimize this strategy.

Genome-Wide Transcriptome and Metabolome Analyses Provide Novel Insights and Suggest a Sex-Specific Response to Heat Stress in Pigs

Heat stress (HS) negatively impacts pig production and swine health. Therefore, to understand the genetic and metabolic responses of pigs to HS, we used RNA-Seq and high resolution magic angle spinning (HR-MAS) NMR analyses to compare the transcriptomes and metabolomes of Duroc pigs (n = 6, 3 barrows and 3 gilts) exposed to heat stress (33 °C and 60% RH) with a control group (25 °C and 60% RH). HS resulted in the differential expression of 552 (236 up, 316 down) and 879 (540 up, 339 down) genes and significant enrichment of 30 and 31 plasma metabolites in female and male pigs, respectively. Apoptosis, response to heat, Toll-like receptor signaling and oxidative stress were enriched among the up-regulated genes, while negative regulation of the immune response, ATP synthesis and the ribosomal pathway were enriched among down-regulated genes. Twelve and ten metabolic pathways were found to be enriched (among them, four metabolic pathways, including arginine and proline metabolism, and three metabolic pathways, including pantothenate and CoA biosynthesis), overlapping between the transcriptome and metabolome analyses in the female and male group respectively. The limited overlap between pathways enriched with differentially expressed genes and enriched plasma metabolites between the sexes suggests a sex-specific response to HS in pigs.

Neutrophils: Novel key players in Rheumatoid Arthritis. Current and future therapeutic targets

Rheumatoid Arthritis (RA) is a complex systemic autoimmune disease in which various cell types are involved. Among them, neutrophils have been recognized as important players in the onset and the progression of RA. The pathogenic role of neutrophils in RA lies in the alteration of several processes, including increased cell survival and migratory capacity, abnormal inflammatory activity, elevated oxidative stress and an exacerbated release of neutrophil extracellular traps. Through these mechanisms, neutrophils can activate other immune cells, thus perpetuating inflammation and leading to the destruction of the cartilage and bone of the affected joint. Given the considerable contribution of neutrophils to the pathophysiology of RA, several studies have attempted to clarify the effects of various therapeutic agents on this subtype of leukocyte. To date, recent studies have envisaged the role of new molecules on the pathogenic profile of neutrophils in RA, which could represent novel targets in future therapies. In this review, we aim to review the pathogenic role of neutrophils in RA, the effect of conventional treatments and biologic therapies, and the new, potential targets of neutrophil-derived molecules for the treatment of RA.

Increase of CD25 expression on bovine neutrophils correlates with disease severity in post-partum and early lactating dairy cows

Polymorph-nuclear neutrophils (PMN) in cattle exhibit unique features when compared to human or murine PMN and are of particular interest concerning the risk of post-partum mammary gland or extra-mammary infections related to the periparturient suppression of neutrophil functions. Former studies could show that effects of IL-2 on innate immune cells such as PMN were mediated by the interleukin-2 receptor (IL-2R) β and γ chains. In the current study we could detect IL-2Rα (CD25) expression on bovine PMN using flow-cytometric analysis. CD25 was detected on granulocytes from post-partum and early lactating cows with different inflammatory conditions. The expression of CD25 on PMN in blood and raw milk increased with disease severity. Our results suggest CD25 expression on PMN as a potential biomarker for acute infections in cattle. Furthermore, our data provide a basis to better understanding of the periparturient functional suppressions of PMN that might reveal new molecular targets for therapy or prevention of disease.

Relationship between cortisol and acute phase protein concentrations in female rabbits

Rabbit meat production in Europe is usually based on a semi-intensive system, in which lactation and gestation overlap. The demands of lactation and pregnancy are likely to be relatively stressful for female rabbits and may compromise the immune system and reproductive performance. The present study was designed to characterise circulating levels of cortisol, haptoglobin (Hp), C-reactive protein (CRP), and serum amyloid A (SAA) in non-lactating and lactating female rabbits at first and second mating, and to determine whether any relationship exists between these biomarkers and litter size. Serum cortisol concentrations were at their greatest (mean ± SEM = 39.5 ± 3.9 nmol/L) in animals at the end of lactation. However, after weaning, cortisol concentrations were not significantly different compared to nulliparous females (19.9 ± 3.6 vs. 16.3 ± 2.2 nmol/L, respectively). The highest concentrations of circulating Hp (0.14 ± 0.01 g/L) were seen in early lactating primiparous females, and lower in nulliparous females and in rabbits after weaning. In contrast, nulliparous female rabbits showed the highest plasma CRP values (13.1 ± 1.1 mg/L). No significant differences were found for SAA. Nulliparous females had smaller litter sizes than early lactating and non-lactating primiparous female rabbits. CRP and SAA showed a positive correlation (r = +0.24, P = 0.011) and were negatively related to litter size (r = -0.23, P = 0.017 and P = 0.032, respectively). Cortisol and Hp were not related to CRP, SAA, nor to litter size. These results suggest a closer association between the mechanisms that regulate release of CRP and SAA, compared to those that regulate Hp production. Thus, lactation is associated with changes in several stress biomarkers. CRP and SAA might be more useful for evaluating animal welfare and for predicting subsequent reproductive performance of female rabbits.

A multidisciplinary approach to assess the welfare of weaned pigs during transport at three space allowances

Transport can be a stressful experience for pigs, especially in pigs simultaneously experiencing weaning stress. The objective of this study was to use a multidisciplinary approach to assess the welfare of weaned pigs during transport at 3 space allowances. A commercial semitrailer, fitted with compartments, provided 0.05, 0.06, and 0.07 m(2)/pig. The study recorded frequency of standing, lying, sitting, and standing-rearing on another pig during the entire duration of transport. Blood samples, body weights, and lesion scores were collected from a subset of pigs (n = 48 per space allowance) in each experimental compartment. Transport time for the pigs was 148.0 +/- 10.0 min to the wean-to-finishing site. Total white blood cell counts, cortisol, and several blood chemistry values increased (p < .05) after transport regardless of space allowance. Glucose and body weight decreased (p < .05) after transport regardless of space allowance. Space allowance influenced stand-rearing, sitting, standing, and lying behaviors in pigs. Combining behavioral and physiological measures of stress provides a robust picture of piglet welfare during transport at different space allowances.

Space requirements of weaned pigs during a sixty-minute transport in summer

Currently, there are no trucking quality assurance recommendations for space allowance of weaned pigs during transport in the United States. The objective of this research was to establish a first estimate of the space requirements of weaned pigs during transport in summer based on measures of animal well-being. A commercial semi-trailer was fitted with compartments that provided 0.05, 0.06, and 0.07 m(2)/pig, which were replicated on the upper and lower deck, with a constant 100 pigs per compartment. Cameras were placed in each experimental compartment to record behaviors and postures of pigs during transport. The frequencies of standing, lying, sitting, standing/rearing on another pig, and lying/huddling on top of another pig were recorded using 1-min scan samples during the entire duration of transport. Blood samples were collected and BW and lesion scores recorded from 32 pigs per space allowance for physiological and immune measures before and after transport (n = 32 pigs/treatment). Pigs were transported for 60 +/- 5 min to the wean-to-finishing site using the same route for each replicate during summer (temperature: 28.4 +/- 1.2 degrees C and relative humidity: 59.8 +/- 4.4% within the trailer). Data were analyzed using the MIXED procedure (SAS Institute Inc., Cary, NC). Cortisol, hematocrit, blood urea nitrogen, total protein, albumin, aspartate aminotransferase, creatine kinase, and gamma-glutamyl transferase increased (P < 0.05) after transport regardless of space allowance. Plasma glucose and BW decreased (P < 0.05) after transport regardless of space allowance. Lesion scores increased (P < 0.001) after transport and were greater (P < 0.05) for barrows compared with gilts. The neutrophil to lymphocyte ratio was greater (P < 0.005) for pigs transported at 0.05 m(2)/pig compared with pigs transported at 0.06 and 0.07 m(2)/pig. Pigs transported at 0.05 m(2)/pig lay down less (P < 0.05) than pigs transported at 0.06 and 0.07 m(2)/pig between 30 and 60 min of transport. Greater neutrophil to lymphocyte ratio and less lying behavior performed by pigs transported at 0.05 m(2)/pig suggest that a minimum space allowance of 0.06 m(2)/pig was preferable when transporting weaned pigs for 60 min during summer in this study.

Human blood neutrophil responses to prolonged exercise with and without a thermal clamp

The purpose of this study was to investigate the effects of prolonged exercise with and without a thermal clamp on neutrophil trafficking, bacterial-stimulated neutrophil degranulation, stress hormones, and cytokine responses. Thirteen healthy male volunteers (means ± SE: age 21 ± 1 yr; mass 74.9 ± 2.1 kg; maximal oxygen uptake 58 ± 1 ml·kg−1·min−1) completed four randomly assigned, 2-h water-immersion trials separated by 7 days. Trials were exercise-induced heating (EX-H: water temperature 36°C), exercise with a thermal clamp (EX-C: 24°C), passive heating (PA-H: 38.5°C), and control (CON: 35°C). EX-H and EX-C was comprised of 2 h of deep water running at 58% maximal oxygen uptake. Blood samples were collected at pre-, post-, and 1 h postimmersion. Core body temperature was unaltered on CON, clamped on EX-C (−0.02°C), and rose by 2.23°C and 2.31°C on EX-H and PA-H, respectively. Exercising with a thermal clamp did not blunt the neutrophilia postexercise (EX-C postexercise: 9.6 ± 1.1 and EX-H postexercise: 9.8 ± 1.0 × 109/liter). Neutrophil degranulation decreased ( P < 0.01) similarly immediately after PA-H (−21%), EX-C, and EX-H (−28%). EX-C blunted the circulating norepinephrine, cortisol, granulocyte-colony stimulating factor, and IL-6 response ( P < 0.01) but not the plasma epinephrine and serum growth hormone response. These results show a similar neutrophilia and decrease in neutrophil degranulation after prolonged exercise with and without a thermal clamp. As such, the rise in core body temperature does not appear to mediate neutrophil trafficking and degranulation responses to prolonged exercise. In addition, these results suggest a limited role for cortisol, granulocyte-colony stimulating factor, and IL-6 in the observed neutrophil responses to prolonged exercise.

Impacts of chronic stress and social status on various physiological and performance measures in pigs of different breeds

Pigs typically experience various environmental stressors, which can negatively affect performance. Cortisol concentrations and various immune and performance measures are influenced by breed, but few data exist describing the impact of breed on stress responsiveness in pigs. The objective of this experiment was to determine if certain physiological responses to chronic stressors differed among 3 breeds and 2 commercial lines of pigs. The pigs were Landrace (n = 36), Meishan (n = 30), Yorkshire (n = 32), or 1 of 2 commercial lines (Line-A and Line-B; both n = 36). All pigs were weaned at 17 to 21 d and kept in a common nursery. At 49 d of age, pigs were assigned to 1 of 2 treatments: stress (heat, crowding, and mixing) or control (no stress treatment). Pigs were allocated to groups of 3 pigs per pen of the same sex. Control pigs were kept with their littermates. At the onset of the experiment, stressed pigs were mixed with 2 unfamiliar pigs once, and heat and crowding stressors were implemented simultaneously for 14 d. Pigs allocated to the stress treatment were video-recorded for 24 h following initiation of mixing to determine social status: dominant, intermediate, or submissive. Blood samples were taken at d 0 (baseline), 1, 7, and 14 to assess cortisol concentrations and immune measures. Breed and treatment affected cortisol, immune, and performance measures, but no significant breed x treatment interactions were found. In general, pigs subjected to the chronic stressor had lower (P < 0.001) BW and ADG (P < 0.001) than did control pigs. Plasma cortisol was lower (P < 0.001) among stressed pigs at d 7 and 14. Regardless of breed, lipopolysaccharide-induced proliferation (P < 0.01) and natural killer (NK; P < 0.005) cytotoxicity were greater in stressed pigs compared with controls. Furthermore, among stressed pigs, dominant pigs had a greater total white blood cell count (P < 0.005), NK (P < 0.05), and phagocytosis (P < 0.05) than the subordinate pigs. The results indicate that pig breed did not influence the physiological responses to the chronic concurrent stressors imposed for 14 d in this study, but social status did influence the immune responsiveness of these pigs to heat, crowding, and mixing.

Making sense of apparently conflicting data: Stress and immunity in swine and cattle1

Stress is generally considered to suppress the immune system and may lead to an increase in the occurrence of disease in the presence of a pathogen. The immune system is ordinarily brought back to a baseline response level after immune challenge through homeostatic processes, in part regulated by the hypothalamic-pituitary-axis. Often, findings reported from various studies investigating the effects of stress on the immune system are conflicting and difficult to reconcile into a cohesive and comprehensible set of universally applicable theories. These discrepancies may be partly explained by the types and durations of the stressors, the aspect(s) of immune system measured, genetics, and social status. A particular stressor may enhance cell-mediated immune responses while suppressing humoral responses or vice versa, thus disrupting the balance between these components of the immune system. How farm animals perceive their environment depends not only on traditional environmental stressors (e.g., heat, cold, humidity, pollutants), but also on aspects of their social environment. Dominant animals may have enhanced immune activation, whereas subordinates have suppression of the same immune component in response to the same stressor. This could explain why individual animals within a group respond differently to stressors and disease challenges. A better understanding of the consequences and complex interactions between social and environmental stressors for innate and adaptive immune traits must be developed so we can more fully understand the effects of stress on immunity in livestock. Once these complex relationships are better understood, more effective interventions can be designed to improve animal health and well-being.

Immune responses of piglets to weaning stress: impacts of photoperiod

An acute stress response can be provoked by abrupt social, nutritional, and environmental changes associated with weaning, and this may disrupt homeostasis and thus compromise well-being. Manipulating environmental factors, such as photoperiod, might provide a simple way to reduce the physiological consequences that piglets experience due to weaning stress. The objective of this study was to evaluate the impacts of photoperiod manipulation across various weaning ages on leukocyte populations, lymphocyte proliferation, natural killer cytotoxicity (NK), chemotaxis, phagocytosis, and immunoglobulin G, cortisol, and BW of piglets during the nursery phase. Sixty-eight crossbred piglets were obtained from sows kept on a short-day (8 h of light/d) photoperiod from d 90 of gestation until weaning. Piglets were weaned at 14, 21, or 28 d of age and kept on a short or long (16 h of light/d) photoperiod until 10 wk of age. Piglet BW and blood samples were collected at weaning and at 6, 8, and 10 wk of age. Pigs weaned at 28 d had reduced neutrophil counts (P < 0.001), phagocytosis (P < 0.001), and lymphocyte proliferation (P < 0.05) at weaning compared with those weaned at 14 and 21 d. Pigs weaned at 21 d tended to have lower (P = 0.08) lymphocyte counts than did pigs weaned at 14 or 28 d. Pigs weaned at 14 d had reduced (P < 0.01) NK relative to those weaned at 21 or 28 d. Photoperiod also influenced pig BW and immune status. Generally, those pigs on the long-day photoperiod and weaned at 28 d were heavier (P < 0.001) than their counterparts weaned at 14 or 21 d. At 6 wk of age, NK was greater (P = 0.002) in pigs kept on a long day and weaned at 14 or 21 d than in pigs weaned at 28 d. Phagocytosis was less (P = 0.005) at 6 wk of age, but was greater at 8 wk, in piglets kept on the long day and weaned at 28 d than in long-day pigs weaned at 14 or 21 d. These results suggest that photoperiod differentially influences immune responses in piglets weaned at different ages and indicate an inverse relationship between growth and immune status. Here, weaning at 28 d and a long-day photoperiod was the treatment combination that was most physiologically beneficial to piglets, whereas a 14-d weaning and short-day photoperiod was least physiologically beneficial.

Photoperiod influences the immune status of multiparous pregnant sows and their piglets1

Manipulation of photoperiod may provide a noninvasive, easily implemented, effective method to improve immune status and enhance the efficiency of production. The objective of this study was to evaluate the impact of manipulation of photoperiod on endocrine and immune responses of pregnant sows and their offspring. At d 83 of gestation, sows were moved to gestation stalls and kept on a photoperiod of 12 h of light:12 h of dark until d 90, when sows were assigned to a long day (LD; 16 h of light/d) or a short day (SD; 8 h of light/d) treatment. During farrowing and lactation, one-half of the sows remained on their initial photoperiod (LD:LD or SD:SD), whereas one-half were switched to the opposite treatment (LD:SD or SD:LD). Blood samples were collected from sows at d 0, 7, 14, and 21 posttreatment, 24-h postfarrowing, and the end of lactation (approximately d 21 postfarrowing). Piglets were bled at 7 and 21 d of age for immune measures. Relative to sows on LD, sows on SD had greater concanavalin A- (P = 0.003) and lipopolysaccharide- (P = 0.02) induced proliferative responses at d 7 but reduced responses at d 14. Compared with SD, sows on LD had a greater (P < 0.05) percentage of neutrophils and fewer (P < 0.05) lymphocytes at d 7, resulting in a greater (P = 0.05) neutrophil:lymphocyte ratio. Neutrophil phagocytosis was greater at d 21 in sows kept on LD. Cortisol concentrations tended to be greatest (P = 0.10) in sows on SD:SD at 24-h postfarrowing and throughout lactation. At 7 d of age, piglets on LD:SD had greater (P = 0.001) total white blood cells (WBC) and plasma cortisol (P = 0.001) relative to those on the other photoperiod treatments. Plasma immunoglobulin G was less (P = 0.001) in piglets from sows kept on SD:LD compared with the other photoperiod treatments. Piglets from sows kept on LD:LD tended to have lower total WBC (P = 0.08) at 21 d of age. Piglets from sows kept on SD:SD had greater concanavalin A- (P < 0.001) and lipopolysaccharide-induced (P < or = 0.10) proliferation responses and cortisol (P = 0.05). Phagocytosis was greater (P < 0.003) in piglets from sows that were kept on LD:LD. Cortisol (P = 0.02), WBC (P = 0.003), and immunoglobulin G (P = 0.001) were all influenced by gestational photoperiod treatment. These data indicate that photoperiod influences the immune status and endocrine response of piglets from dams that have been kept on a defined photoperiod. We conclude that photoperiod effects on piglets may be programmed in utero and can last throughout lactation.

Evaluation of drop versus trickle-feeding systems for crated or group-penned gestating sows1

A total of 160 gilts were used to evaluate the effects of pen vs. crated housing systems and drop- vs. trickle-fed feeding systems on sow productivity, occurrence of lesions during farrowing and weaning, immune measures, and behavioral responses during 2 consecutive gestation periods. Of the 160 eligible gilts, 117 farrowed in parity 1, and of those, 72 farrowed in parity 2. The gilts were randomly assigned to represent 1 of 4 factorially arranged treatment groups: pen drop-fed, crate drop-fed, pen trickle-fed, or crate trickle-fed. Replicate blocks were used for each parity with 5 sows per block initially in each treatment. At weaning, sows housed in pens had greater (P < 0.05) backfat thickness than sows housed in crates. The piglet weaning weight was greater (P < 0.05) for sows fed with the single drop compared with the trickle-feeding system. Lesions scores and all other productivity measures did not differ among treatments. An interaction was observed for percentage of neutrophil phagocytosis (P < 0.05) between penning and feeding systems. In pens, drop-fed sows had greater phagocytosis than trickle-fed sows, but in crates, drop-fed sows had a tendency for lower phagocytosis than trickle-fed sows. All other immune measures were not different among treatments. The occurrence of oral-nasal-facial (ONF) behaviors (chewing, rooting, and rubbing) and active behaviors increased, and lying behavior decreased (P < 0.05), from 0800 to 1200 for all sows. During the 0800 to 1200 period, crate drop-fed sows displayed more (P < 0.05) ONF and active behaviors than did sows in the 3 other treatments. Sows housed in groups of 5 had a greater (P < 0.05) duration of standing in the 0400 to 0800 period compared with crated sows. Housing systems had complex effects on sow behavioral sequences, but penned sows had more sequences associated with stress than did crated sows. Also, crate drop-fed gilts and sows expressed more ONF behaviors than gilts and sows in other treatments. Generally, productivity, skin lesions, and immune measures were not different, but behaviors at certain times of day and behavioral sequences were different for sows in pens and crates with drop or trickle-feeding systems. None of the environments evaluated were associated with significant physiological stress responses among the sows. Thus, sows were able to adapt within each environment through behavioral mechanisms without the need to invoke major physiological adjustments.

Breed and age affect baseline immune traits, cortisol, and performance in growing pigs1

It was hypothesized in these studies that differences would exist in baseline immune and performance measures among different breeds of pigs, and that these differences would be affected by age of the pig. Baseline immune, plasma cortisol (CORT) concentrations, and performance measures were determined among Berkshire (n = 36), Duroc (n = 18), Meishan (n = 54), Landrace x Yorkshire (White X; n = 36), and Yorkshire (n = 36) pigs at 4, 8, and 12 wk of age. All piglets were weaned at 17 to 21 d of age and moved to a common nursery environment. Total white blood cell (WBC), leukocyte differential, plasma CORT, immunoglobulin G (IgG) concentrations, natural killer cytotoxicity, neutrophil phagocytosis (PHAGO), and chemotaxis (CHTX) were evaluated. At all ages, plasma CORT was greatest in Meishan pigs, and least in Yorkshires (P < 0.05). Plasma IgG increased with age for all breeds (age: P < 0.01; breed x age: P < 0.005), except that in Meishans, IgG decreased. Natural killer cytotoxicity was greatest (P < 0.05) among Meishan pigs. There were breed x age interactions for neutrophil PHAGO (P < 0.001) and CHTX (P < 0.001). Overall, Yorkshire pigs showed the greatest (P < 0.05) percentage of PHAGO but the least (P < 0.05) CHTX. White X pigs had the greatest (P < 0.05) CHTX response. Berkshire pigs had the greatest (P < 0.001) numbers of neutrophils. At 12 wk of age, Meishan pigs had the least BW gain (P < 0.001), and Durocs had the greatest G:F (P < 0.001). There were no significant sex differences for immune (P > or = 0.15), performance (P > or = 0.20), or CORT (P = 0.70) measures. Pig breed and age influenced both baseline immune measures and plasma CORT in growing pigs, suggesting that pig breed and age are important factors influencing the response to various stressors or infectious challenges.

Intraepithelial but not lamina propria lymphocytes in the porcine gut are affected by dexamethasone treatment

It is well established that glucocorticoids are key regulators of the immune system and act as immunosuppressive agents in high concentrations. In the pig, effects on the gut immune system and trafficking of lymphocytes between tissues and blood plasma were not investigated so far. Twelve pigs of 70 kg were fed 0.4 mg portions of dexamethasone (Dexa) twice daily for 9 days or remained untreated (controls) and were sacrificed for tissue collection at the end of Dexa treatment. Another six pigs with jugular vein catheters were left untreated for 7 days (control period) and then received Dexa for 9 days. Blood was drawn twice during the control period and at days 3, 6 and 9 of the Dexa period for characterization of peripheral blood leukocytes. Cells were obtained from thymus, mesenteric lymph nodes, jejunal mucosa and Peyer's patches. Lymphoid cells from gut tissue were isolated from two fractions: the EDTA-fraction, containing the intraepithelial lymphocytes (IEL), and the Collagenase-fraction, containing the lamina propria lymphocytes (LPL). In all samples, cell counts and phenotypic characterization of cells by flow cytometry (FCM) were performed. In thymus, Dexa led to a more than 90% reduction of the absolute cell number, which was mainly found in the CD4+CD8+ subpopulation. Dexa effects on lymphocytes from mesenteric lymph nodes were less severe (50%) and led mainly to a decrease (71%) of B-lymphocytes. The number of lymphocytes in the EDTA-fraction (IEL) of the jejunal mucosa decreased significantly by 56% in the Dexa-treated animals compared to the controls, whereas the number of lymphocytes in the Collagenase-fraction (LPL) decreased only moderately. In the Peyer's patches, a decreasing tendency in the number of lymphocytes in the EDTA-fraction was observed which, however, was not significant. In blood, monocytes and granulocytes were significantly increased in an order of 60%. The data show that supraphysiological amounts of Dexa remarkably reduce cell numbers in thymus and also in the intraepithelial compartment of the jejunal mucosa and ileal Peyer's patches. In blood, a notable homeostasis was observed for several leukocyte populations whereas both monocytes and granulocytes increased.

Measurement of phagocytosis and oxidative burst of canine neutrophils: high variation in healthy dogs

Quantitative analysis of phagocytosis and oxidative burst in canine polymorphonuclear (PMN) cells was performed by flow cytometry techniques. Different concentrations of phorbol myristate acetate (PMA) were used to modulate PMN phagocytosis. A low concentration of PMA (3 nmol) resulted in increased phagocytic activity of canine PMN, which could not be enhanced by higher dosages. Experiments with a reference cell population showed high losses of PMN, most probably by adherence to plastic material. It was possible to avoid this loss by layering all ingredients on cushions of Histopaque. However, Histopaque had a negative influence on the phagocytic activity of canine PMN. The use of PMA led to a dosage-dependent increase in the oxidative burst measured by the production of reactive oxygen species (ROS). Cushions of Histopaque were used to avoid cell loss. There was no negative influence of Histopaque on ROS formation. Storage of canine PMN for 24 h at room temperature had no negative influence on phagocytosis or oxidative burst measurements. Variations in the ROS assays conducted by two different examiners could be eliminated by use of a Histopaque-cushion.

The effect of the cyclopropyl group on the conformation of chemotactic formyl tripeptides

Certain formyl peptides are powerful chemoattractants towards neutrophils. In this study, several formyl tripeptides were synthesized and used to investigate the effects of different amino acid residues in position 1 on their ability to stimulate neutrophil chemotaxis. Pig neutrophil chemotaxis towards the formyl tripeptide, HCO-Ac(3)C-Leu-Phe-OMe 1, where Ac(3)C represents 1-amino-1-cyclopropane carboxylic acid, was observed. Pig neutrophil chemotaxis towards a very similar formyl tripeptide, HCO-Aib-Leu-Phe-OMe 2, where Aib represents alpha-amino isobutyric acid, was not observed. Compared to the isopropyl group, it was shown that the cyclopropyl group induces a greater percentage of the E conformation about the formamide functionality in these peptides. For 1 and 2, the E isomer distributions in CDCl3 are 36 and 9%, respectively. Since a major difference between these two peptides is the Z/E isomeric distribution, one implication is that the peptide-receptor site interactions involving the E conformer are more effective than those of the Z conformer. No pig neutrophil chemotaxis towards the formyl tripeptides, HCO-Ala-Leu-Phe-OMe 3 and HCO-Gly-Leu-Phe-OMe 4 was observed. These formyl tripeptides exhibit a low percentage of the E isomer, similar to that of peptide 2.

Phenotypic and functional changes on phagocytic cells recruited at the site of Candida albicans infection after chronic varied stress exposure

The transition of Candida albicans from commensalism to pathogenicity is associated with the immune status of the host; resistance to fungus involves macrophages (Mphi) and polymorphonuclear neutrophils (PMN), which act as effector cells. T-cell function is also involved. Previously, we found that in Wistar rats exposed to chronic varied stress (CVS) immediately after C. albicans infection (Ca-S group) some functions of phagocytic cells, such as killer activity and NO production, were strongly modified compared with unstressed, infected animals (Ca group). We examined the phenotypic and functional changes of these effector cells recruited at the site of C. albicans infection. The recruitment of peritoneal cells (PC) was markedly reduced in Ca-S animals and the arrival of Mphi and PMN was selectively diminished after CVS exposure. The integrin CD11b/CD18, implicated in migration and C. albicans phagocytosis, was downregulated in Mphi of Ca-S animals. The activation markers CD54 and MHC-II were upregulated in Mphi after fungal contact. The expression of CD54 was only changed in Ca-S rats. Finally, TNF-alpha production was reduced in PC of Ca-S animals, suggesting an impairment of functional activity. Taken together, the phenotypic and functional changes detected in effector cells may account for the decreased resistance to candidiasis seen in conjunction with CVS. The changes seen also expand our knowledge of the role of Mphi in the control of C. albicans dissemination.

Effect of low-dose prednisone in vivo on the ability of complement receptor to mediate an oxidative burst in rat neutrophils

Glucocorticoids have been used in the treatment of a variety of inflammatory processes including autoimmune diseases. However, the influence of low-dose glucocorticoids on the respiratory burst activity of neutrophils has not been studied. The aim of this work was to study the effect of treatment with low-dose prednisone on the oxidative burst of rat peripheral blood neutrophils. Wistar male rats were treated with prednisone by gavage (28, 87 or 257 microg/animal/day) for 7 or 15 days. These doses are equivalent to 10, 30 or 90 mg/adult human ( approximately 70 kg)/day, respectively. Sera from normal rats were used to opsonize zymosan (opZy). Neutrophils (1x10(5)) were stimulated by opZy and the oxidative burst of control or treated rat cells was measured by luminol-dependent chemiluminescence (CL). Prednisone did not affect the CL of rat neutrophils for either period of treatment, or any studied doses, when compared with controls. These results suggest that the low-dose prednisone has no effect on the oxidative burst mediated by complement receptors during the rat neutrophil phagocytosis of complement-opZy.

Presence of cortisol in gingival crevicular fluid. A pilot study

Cortisol is one of the primary mediators of the stress response, in the main having immunosuppressive effects. An important component of the host response in periodontal inflammation is gingival crevicular fluid (GCF), with constituents mainly derived from serum. Cortisol, like many other steroids, is present in saliva but its occurrence in GCF does not seem to be documented. Unstimulated whole saliva was collected and GCF was sampled on filter disks. The samples were analysed by a modified RIA method for serum in such a way that small volumes and low concentrations could be measured. Our findings suggest that the total concentration of cortisol in GCF might be estimated to levels below 1/10 of that in serum. However, what appears as a distinctive feature is the considerable variation of the cortisol concentrations for individual teeth. To our knowledge, this is the first time cortisol has been measured in gingival crevicular fluid, and this opens the prospects for further in vivo research.

Effect of lidocaine on neutrophil chemotaxis in newborn infants

Anesthetic drugs can influence the immune system, particularly granulocyte function. The goal of the present study was to evaluate if lidocaine used for epidural anesthesia during cesarean section can influence neonatal neutrophil chemotaxis. We measured chemotaxis and plasma cord lidocaine and cortisol levels in (A) 15 infants born by cesarean section with epidural anesthesia, (B) 15 infants born by vaginal delivery, and (C) 20 infants born by cesarean section with general anesthesia. Chemotaxis levels were significantly lower in group A infants (35.5 +/- 16.1 microns) compared to groups B (54.6 +/- 10.5 microns) and C (71.4 +/- 23 microns). The highest cortisol levels were observed in vaginally delivered infants. A significant inverse relationship was observed between chemotaxis and lidocaine levels (r = -0.6, P = 0.016) in infants born by cesarean section after epidural anesthesia, while no significant correlation was observed between chemotaxis and cortisol level. In conclusion, lidocaine, transferred through the placenta to the fetus during epidural anesthesia, may have an inhibitory effect on chemotaxis.

Intracerebroventricular porcine corticotropin-releasing hormone and cortisol effects on pig immune measures and behavior

The effects of intracerebroventricular (icv) administration of porcine corticotropin-releasing hormone (pCRH) and cortisol on the immune system and behavior were examined in domestic pigs. In Experiment 1, 50 micrograms of pCRH in 200 microliters of saline or 200 microliters of vehicle was administered i.c.v. at 0600 h. Blood samples were obtained at 0600 (prior to injection), 0700, and 0800 h. Plasma cortisol concentrations were higher at 1 and 2 h after pCRH than after saline. Generally, pCRH failed to effect NK cytotoxicity or lymphocyte proliferation in response to phytohemagluttin (PHA). However, 1 h postinjection, pigs administered pCRH i.c.v. had marginally lower NK activity than control pigs. Pigs injected with pCRH had substantially lower neutrophil chemotaxis (CHTX) than the control pigs at 1 and 2 h postinjection. As blood cortisol concentration increased, neutrophil CHTX decreased. Pigs injected i.c.v. with pCRH had higher neutrophil numbers and neutrophil:lymphocyte ratios than control pigs. Percentage of lymphocytes was higher among control than treated pigs. Central pCRH increased overall activity, particularly walking, standing, licking, rooting, and increased activity-related sequences (e.g., sit, walk and stand, walk), but reduced complex oral/nasal sequences (e.g., root, lick). In Experiment 2, pigs were injected i.c.v. with 10 micrograms of cortisol in 200 microliters of saline or with vehicle at 0600 h. Administration of cortisol failed to effect NK cytotoxicity, lymphocyte proliferation, CHTX, or leukocyte distribution. Pigs given cortisol had no apparent change in behavior. These data indicate leukocyte distribution and specific neutrophil function in pigs were significantly modulated by stress-related hormones of the hypothalamic-pituitary-adrenal axis and complexity of behavioral sequences (pigs repeating certain behavioral sequences) associated with increased activity was reduced. Oral/nasal stereotypies (as seen among confined sows) were not elevated among pigs given i.c.v. pCRH. CRH given by i.c.v. administration may serve as a better model for acute rather than chronic stress.