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Abstract

Objective

To evaluate effects of thermal environment on response to acute peripheral lipopolysaccharide (LPS) challenge exposure in neonatal pigs.

Animals

26 neonatal pigs.

Procedure

Pigs were assigned to the following treatment groups: 1 warm environment/LPS; 2 warm environment/saline solution; 3 cool environment/LPS; and 4 cool environment/saline solution. For each pig given LPS. 1 littermate of the same sex was given saline solution. Sows with baby pigs were housed in a warm (32 C) or cool (21 C) thermal environment. At 28 days of age, pigs were given 150 µg/kg of body weight of Escherichia coli LPS or saline solution intraperitoneally as a control. Rectal temperature and signs of sickness were monitored for 3 hours after LPS administration, when pigs were euthanatized and blood samples were collected to determine serum concentrations of tumor necrosis factor (TNF) α and cortisol. To determine in vitro production of TNFα, alveolar macrophages were collected by tracheal lavage and incubated for 24 hours at 37 or 41 C, with or without LPS (10 µg/ml).

Results

Thermal environment had a significant (P = 0.0004) effect on rectal temperature; LPS administration induced a febrile response (P = 0.0007) only in pigs in the warm environment. All LPS-injected pigs developed signs of endotoxemia; serum TNFα and cortisol concentrations were significantly increased (TNFα, P = 0.003; cortisol, P = 0.0001); there was no significant in vivo thermal effect on serum TNFα and cortisol concentrations. LPS-stimulated alveolar macrophages produced significantly less (P = 0.0086) TNFα when incubated at 41 C.

Conclusions

Thermal environment can have a significant impact on the response of neonatal pigs exposed to bacterial endotoxins. (Am J Vet Res 1997; 58:364-369)

Free access
in American Journal of Veterinary Research

SUMMARY

We quantified the effect of passive immune status on pre- and postweaning health and growth performance of calves raised in a beef production environment. Blood samples were collected at postpartum hour 24 from 263 crossbred calves for determination of plasma protein (pp) and serum IgG concentrations. Serum IgG concentration was classified as adequate (> 1,600 mg/dl), marginal (800 to 1,600 mg/dl), or inadequate (< 800 mg/dl). Plasma protein concentration was classified as adequate (≥ 4.8 g/dl) or inadequate (< 4.8 g/dl). Morbidity and mortality events in the study population were monitored from birth to weaning, and after weaning throughout the feeding period. The lowest concentrations of serum IgG and pp were observed among calves that experienced morbidity or mortality prior to weaning. Calves that experienced morbidity in the feedlot had lower 24-hour pp values, but had IgG concentration similar to that in calves that were not observed to be ill during the feeding period. Calves classified as having inadequate IgG concentration were at greater risk of preweaning mortality (odds ratio [or] = 5.4), neonatal morbidity (or = 6.4), and preweaning morbidity (or = 3.2), compared with calves classified as having adequate IgG concentration at 24 hours. Calves classified as having inadequate pp concentration at 24 hours had a greater risk of morbidity (or = 3.0) and respiratory tract morbidity (or = 3.1) while in the feedlot, compared with calves classified as having adequate pp concentration. The effects of 24-hour passive immune status on calf growth were indirect through effects on morbidity outcomes. Morbidity during the first 28 days of life was associated with a 16-kg lower expected weaning weight. Respiratory morbidity in the feedlot resulted in a 0.04-kg lower expected mean daily gain. Thus, passive immune status at postpartum hour 24 was an important determinant of health before and after weaning, and was indirectly associated with calf growth during the same periods.

Free access
in American Journal of Veterinary Research

Summary

Polymorphonuclear neutrophils (pmn) from 4 cows were preincubated (30 minutes, 37 C) in either actinomycin D (100 μg/ml) or puromycin (10 μg/ ml), inhibitors of mRNA transcription and protein translation, or in medium 199. The pmn were incubated for a further 4.5 hours in medium containing 100 U of recombinant bovine interferon-γ (rbolfn-γ). The pmn were then incubated with bovine IgG1, IgG2, IgM, or aggregated IgG (algG; 4 C, 12 hours) for flow cytometric analysis, using fluoresceinated is-otype-specific antibody. The percentage of pmn binding the ligand and the logarithmic mean fluorescent channel (lmfc), an indicator of the amount of receptor (R) expression, were recorded. Competitive inhibition of ligand binding was measured by incubating pmn with fluoresceinated IgG2 in the presence or absence of 100-fold excess of IgG1, IgG2, and aIgG. Activation with rboIfn-γ induced a 4.5-fold increase in binding of IgG1 and a fivefold increase in lmfc for IgG2. These increases were inhibited by actinomycin D and puromycin. Percentage of pmn binding aIgG decreased after activation by rboIfn-γ. Interferon-γ treatment did not affect binding or lmfc of IgM. However, binding of IgM was reduced by treatment with actinomycin D. Binding of fluoresceinated IgG2 was inhibited by unlabeled IgG1, IgG2, and aIgG. Results indicate that bovine pmn Fc receptors (FcR) for IgG1 and IgG2 were rboIfn-γ inducible, that induction required de novo transcription and translation, that a heterogeneous population of FcR exist on bovine pmn, and that IgG1 and IgG2 share a common FcR. Further, bovine pmn are capable of gene activation and are responsive to changes in their environment, thus being amenable to modulation for effective pathogen destruction.

Free access
in American Journal of Veterinary Research

exacerbate the disease in affected animals; afterward, all horses were kept in the same environment with the same feeding regimen and administered dexamethasone b (0.06 mg/kg, PO, q 24 h) for 2 weeks, with blood samples collected after the 3-week challenge

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in American Journal of Veterinary Research

high-altitude environments. 8 Highland plateaus are characterized by strong UV radiation, and such environments induce hypoxia and hypothermia among resident mammals. It has been reported that hypoxia impairs T-cell activation, proliferation, and

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in American Journal of Veterinary Research

conditions, dogs with spontaneous food hypersensitivity may be a good model to investigate the pathogenesis of this disease. In humans, the healthy intestine is associated with a Th1 or tolerant environment 8–10 ; however, the intestinal immune environment

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in American Journal of Veterinary Research

premises to aid in passive transfer of antibodies against pathogens in the local environment. Extra colostrum is routinely frozen and stored for up to 1 year. 3 The benefits of frozen colostrum over the use of milk replacer or cheese-whey–derived antibody

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in American Journal of Veterinary Research

humid, 5% carbon dioxide environment. Test sample wells were assessed for cytopathic effect at 48 to 72 hours by use of an inverted ocular of a light microscope. Endpoint antibody titer was defined as the highest dilution of serum at which virus

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in American Journal of Veterinary Research

a serum-free environment. 8 Phagocytosis of M bovis by porcine alveolar macrophages was blocked by up to 60% by addition of anti-CD14 antibody. 23 The ligand for CD14 is uncertain, but it appears that lipoarabinomannan may bind it. 25 Other

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in American Journal of Veterinary Research

System, Bio-Rad Laboratories Inc, Hercules, Calif. o. PJ-34, Enzo Life Sciences Inc, Farmingdale, NY. p. Veliparib, Enzo Life Sciences Inc, Farmingdale, NY. q. Olaparib, Selleck Chemicals, Houston, Tex. r. R: a language and environment for

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in American Journal of Veterinary Research