Ovine hippocampal mRNA expression in offspring from dams supplemented with fishmeal and stress challenged in late pregnancy with endotoxin.

Previous research has shown that adulthood disease can be attributed to stress events that occur during gestation. The objective of the present study was to determine whether maternal stress during late pregnancy, using a bacterial endotoxemia model, causes changes in hippocampal mRNA expression of candidate genes related to hypothalamic-pituitary-adrenal axis (HPAA) regulation in sheep. This study also sought to investigate whether maternal diets supplemented with fishmeal (FM) rich in omega-3 polyunsaturated fatty acids (PUFAs) offer protection to the fetus when subjected to maternal endotoxin stress. Using RT-qPCR, relative mRNA expression was assessed in both fetal lambs and 6-month-old lambs from dams supplemented with soybean meal (SM) or FM and challenged with either endotoxin or saline. From this it was found that fetal mineralocorticoid receptor (MR) gene expression had a tendency to be altered during endotoxin challenge, however, in the 6-month-old offspring, MR and glucocorticoid receptor (GR) gene expression were differently altered across treatment groups. These results suggest that gene regulation within the hippocampus is altered into adulthood by maternal endotoxin stress and that dietary supplementation affects outcome.

Physical Health Problems and Environmental Challenges Influence Balancing Behaviour in Laying Hens.

With rising public concern for animal welfare, many major food chains and restaurants are changing their policies, strictly buying their eggs from non-cage producers. However, with the additional space in these cage-free systems to perform natural behaviours and movements comes the risk of injury. We evaluated the ability to maintain balance in adult laying hens with health problems (footpad dermatitis, keel damage, poor wing feather cover; n = 15) using a series of environmental challenges and compared such abilities with those of healthy birds (n = 5). Environmental challenges consisted of visual and spatial constraints, created using a head mask, perch obstacles, and static and swaying perch states. We hypothesized that perch movement, environmental challenges, and diminished physical health would negatively impact perching performance demonstrated as balance (as measured by time spent on perch and by number of falls of the perch) and would require more exaggerated correctional movements. We measured perching stability whereby each bird underwent eight 30-second trials on a static and swaying perch: with and without disrupted vision (head mask), with and without space limitations (obstacles) and combinations thereof. Video recordings (600 Hz) and a three-axis accelerometer/gyroscope (100 Hz) were used to measure the number of jumps/falls, latencies to leave the perch, as well as magnitude and direction of both linear and rotational balance-correcting movements. Laying hens with and without physical health problems, in both challenged and unchallenged environments, managed to perch and remain off the ground. We attribute this capacity to our training of the birds. Environmental challenges and physical state had an effect on the use of accelerations and rotations to stabilize themselves on a perch. Birds with physical health problems performed a higher frequency of rotational corrections to keep the body centered over the perch, whereas, for both health categories, environmental challenges required more intense and variable movement corrections. Collectively, these results provide novel empirical support for the effectiveness of training, and highlight that overcrowding, visual constraints, and poor physical health all reduce perching performance.

Assessment of yeast Saccharomyces cerevisiae component binding to Mycobacterium avium subspecies paratuberculosis using bovine epithelial cells.

BACKGROUND: Since yeast Saccharomyces cerevisiae and its components are being used for the prevention and treatment of enteric diseases in different species, they may also be useful for preventing Johne's disease, a chronic inflammatory bowel disease of ruminants caused by Mycobacterium avium spp. paratuberculosis (MAP). This study aimed to identify potential yeast derivatives that may be used to help prevent MAP infection. The adherence of mCherry-labeled MAP to bovine mammary epithelial cell line (MAC-T cells) and bovine primary epithelial cells (BECs) co-cultured with yeast cell wall components (CWCs) from four different yeast strains (A, B, C and D) and two forms of dead yeast from strain A was investigated. RESULTS: The CWCs from all four yeast strains and the other two forms of dead yeast from strain A reduced MAP adhesion to MAC-T cells and BECs in a concentration-dependent manner after 6-h of exposure, with the dead yeast having the greatest effect. CONCLUSIONS: The following in vitro binding studies suggest that dead yeast and its' CWCs may be useful for reducing risk of MAP infection.

Fishmeal supplementation during ovine pregnancy and lactation protects against maternal stress-induced programming of the offspring immune system.

BACKGROUND: Prenatally stressed offspring exhibit increased susceptibility to inflammatory disorders due to in utero programming. Research into the effects of n-3 PUFAs shows promising results for the treatment and prevention of these disorders. The purpose of this study was to investigate whether maternal fishmeal supplementation during pregnancy and lactation protects against programming of the offspring's immune response following simulated maternal infection. METHODS: In order to accomplish this, 53 ewes were fed a diet supplemented with fishmeal (FM; rich in n-3 PUFA) or soybean meal (SM; rich in n-6 PUFAs) from day 100 of gestation (gd 100) through lactation. On gd135, half the ewes from each dietary group were challenged with either 1.2 µg/kg Escherichia coli lipopolysaccharide (LPS) endotoxin to simulate a bacterial infection, or saline as the control. At 4.5 months of age the offspring's dermal immune response was assessed by cutaneous hypersensitivity testing with ovalbumin (OVA) and candida albicans (CAA) 21 days after sensitization. Skinfold measurements were taken and serum blood samples were also collected to assess the primary and secondary antibody immune response. RESULTS: Offspring born to SM + LPS mothers had a significantly greater change in skinfold thickness in response to both antigens as well as a greater secondary antibody response to OVA compared to all treatments. CONCLUSIONS: Supplementation during pregnancy with FM appears to protect against adverse fetal programming that may occur during maternal infection and this may reduce the risk of atopic disease later in life.

Phenotypic and genetic parameters of antibody and delayed-type hypersensitivity responses of lactating Holstein cows.

Breeding dairy cattle using diverse phenotypic markers has been suggested as a feasible approach to improve health and decrease the deleterious consequences of infectious diseases. Studies conducted in pigs have demonstrated the value of antibody (AMIR)- and cell (CMIR)-mediated immune responses as quantitative traits for improving immune responsiveness by selecting livestock using estimated breeding values (EBV) for immune response (IR) traits. Studies of cattle have tested the possibility of using IR traits as phenotypic markers to classify cows as high (HR), average (AR) and low (LR) responders. Information is scarce or unavailable about either genetic parameters of AMIR and CMIR or their phenotypic and genetic associations with production, conformation, fertility or health traits in lactating dairy cattle. The objectives of the current study were to evaluate phenotypic and genetic parameters of both AMIR and CMIR as quantitative immunological traits (n=6) in comparison with production, fertility and health traits in dairy cattle for their use in a selection index intended to improve bovine health. Results of this study showed significant AMIR and CMIR responses. Most phenotypic correlations between IR traits and production, health or fertility traits were not significant. The highest heritabilities (h(2)) were observed for delayed-type hypersensitivity (DTH) to killed Candida albicans whole cell (CaWC) at 48 h (0.54) and AMIR day 14 (0.42). The highest genetic correlations were observed between AMIR 14 and AMIR 21 (0.99) and between DTH to CaWC 24h and DTH to CaWC 48 h (0.93). Two important and significant sire EBV correlations were noted between AMIR and fat % (0.18), and between CMIR and protein % (-0.15). In conclusion, this study demonstrated that both AMIR and CMIR are heritable traits in cattle and could be considered for their inclusion in a selection index intended to improve health.

Immunoglobulin isotypes of lactating Holstein cows classified as high, average, and low type-1 or -2 immune responders.

Infectious diseases are detrimental to the health and economy of the livestock industry. Observations of cattle resistant to natural infections have implied the feasibility of breeding livestock for disease resistance. Studies of pigs selected for antibody (AMIR)- and cell (CMIR)-mediated immune responses have demonstrated increased immune responsiveness suggesting enhanced protection by both type 2 and type 1 responses, respectively. Additionally, natural or artificial infections of cattle suggest that the production of particular immunoglobulin (Ig) M, IgG1 and IgG2 isotypes are important for protecting against pathogens. In fact, IgG1/IgG2 ratios are often used to establish whether type 1 (CMIR) or type 2 (AMIR) responses predominate following immunization or infection. The objectives of this study were therefore; (1) to evaluate the Ig isotype bias responses to Candida albicans and hen-egg white lysozyme (HEWL) in cows classified as high responders (HR), average responders (AR) or low responders (LR) based on AMIR or CMIR; (2) to determine if ranking based on IFN-γ (a type 1 cytokine) and DTH responses were analogous in terms of ranking; and (3) to estimate IFN-γ, Ig isotypes, and DTH correlations. Antibody responses to HEWL and DTH to C. albicans were detected such that cows were phenotypically classified as HR, AR and LR for AMIR or CMIR with significant differences (p ≤ 0.05) among classified groups. C. albicans-induced IFN-γ allowed classification of cows, some of which had the same ranking as that of DTH response. The lowest IgG1/IgG2 ratio was to the C. albicans purified antigen (candin), but no differences were observed in anti-HEWL or anti-candin IgG1/IgG2 ratios between classified groups. Anti-HEWL IgG1 and IgG2 responses at day 21 post-immunization were negatively and significantly correlated with DTH to candin at 24h. There were no significant correlations between anti-HEWL or anti-candin IgG1 or IgG2 responses with IFN-γ. Based on Ig isotype bias, IFN-γ and DTH responses, it was concluded that immunization with C. albicans can be used to classify CMIR responder cows based on DTH read-out.

Endotoxin exposure during late pregnancy alters ovine offspring febrile and hypothalamic-pituitary-adrenal axis responsiveness later in life.

A growing number of studies indicate that maternal infection during pregnancy is associated with adverse fetal development and neonatal health. In this study, late gestating sheep (day 135) were challenged systemically with saline (0.9%) or Escherichia coli lipopolysaccharide endotoxin (400 ng/kg x 3 consecutive days, or 1.2 microg/kg x 1 day) in order to assess the impact of maternal endotoxemia on the developing fetal neuroendocrine-immune system. During adulthood, cortisol secretion and febrile responses of female offspring and the cortisol response of the male offspring to endotoxin (400 ng/kg), as well as the female cortisol response to adrenocorticotropic hormone (ACTH) challenge, were measured to assess neuroendocrine-immune function. These studies revealed that maternal endotoxin treatment during late gestation altered the female febrile and male and female cortisol response to endotoxin exposure later in life; however, the response was dependent on the endotoxin treatment regime that the pregnant sheep received. The follow-up ACTH challenge suggests that programing of the adrenal gland may be altered in the female fetus during maternal endotoxemia. The long-term health implications of these changes warrant further investigation.

Antibody to ovalbumin and delayed-type hypersensitivity to Candida albicans and mycobacteria in lactating Holstein cows using Quil A or Freund's complete adjuvant.

Antibody-mediated immune response (AMIR) to ovalbumin (OVA) or hen-egg white lysozyme (HEWL) and cell-mediated immune response (CMIR) such as delayed-type hypersensitivity (DTH) to mycobacteria have been proposed as quantitative traits for selective breeding to improve animal health. However, DTH to mycobacteria may confound diagnosis of tuberculosis in cattle. Candida albicans, a yeast also known to induce DTH, was tested as an alternative for DTH induction and testing since it is not a target of regulatory diagnostic tests. Other objectives were to determine if both AMIR and CMIR in cattle receiving Quil A as adjuvant were equivalent to corresponding responses induced by Freund's complete adjuvant (FCA). Forty lactating Holstein cows were randomly assigned to two treatment groups, which received ovalbumin (OVA) and C. albicans adjuvanted with FCA and Freund's incomplete adjuvant (FIA) on days 0 and 14, respectively, or Quil A on days 0 and 14. The FCA was used as adjuvant and as a source of Mycobacterium tuberculosis-induced DTH. Testing for DTH was performed on day 21 with killed C. albicans whole cell (CaWC), a purified extract from C. albicans (candin) and M. phlei purified protein (phlein). Both primary and secondary antibody responses to OVA were statistically significant and similar in both FCA and Quil A treatment groups. No significant differences were detected in immunoglobulin G (IgG) isotypic-mediated responses to OVA or candin between groups. C. albicans adjuvanted with Quil A induced DTH reaction similar to those induced by C. albicans and mycobacteria in FCA.

Enhanced cutaneous hypersensitivity reactions are associated with ovine high and low cortisol responsiveness to acute endotoxin challenge.

Inbred rodent studies have demonstrated that cutaneous hypersensitivity reactions are exacerbated in stress-susceptible, and attenuated in stress-resistant strains of mice. This physiological response was, in part, mediated by activation of the hypothalamic-pituitary-adrenal axis during the acute restraint stress. A study was conducted to examine whether or not cutaneous hypersensitivity reactions are also associated with variable cortisol responsiveness to inflammatory stress in an outbred ovine population. High (H), medium (M), and low (L) cortisol responsive sheep were identified from a population of 110 females based on their estimated breeding values for cortisol concentration measured 4 h post-systemic challenge with Escherichia coli endotoxin (400 ng kg(-1)). Cutaneous hypersensitivity reactions to phytohaemagglutinin (PHA), 1-chloro-2, 4-dinitrobenzene (DNCB), and Candida albicans cellular antigen (CAA) were measured in these variable cortisol-responding sheep, in addition to serum interleukin (IL)-6, interferon (IFN)-gamma, and ovalbumin (OVA)-specific IgG concentrations. When compared to the M cortisol responders, both H and L cortisol responders had significantly greater cutaneous swelling during the elicitation phase in response to DNCB (P < 0.05) and CAA (P < 0.05); a similar but not significant trend was observed during the PHA challenge. The primary, but not the secondary, IgG response to OVA was significantly lower in the H and L cortisol responders when compared to the M cortisol responders. Differences in serum IL-6 or IFN-gamma concentration were not observed across variable cortisol-responsive groups. Together, these results demonstrate that cutaneous hypersensitivity reactions are enhanced in outbred H and L cortisol-responding sheep, independent of systemic modulation by IL-6 and IFN-gamma.

Assessment of the ovine acute phase response and hepatic gene expression in response to Escherichia coli endotoxin.

Lipopolysaccharide (LPS), a bacterial membrane endotoxin, induces a systemic inflammatory response (IFR) through the activation of blood monocytes and hepatic kupffer cells. These cells secrete pro-inflammatory cytokines, which subsequently activate the hypothalamic-pituitary-adrenal axis (HPAA) to release cortisol, an anti-inflammatory hormone that regulates the IFR and subsequent immune response (IR). The intent of this study was to characterize the acute phase response in female sheep challenged systemically with a range of doses of Escherichia coli endotoxin. Yearling ewes were challenged with an i.v. bolus dose of LPS (0, 200, 400, 600 ng/kg BW) and the acute phase response assessed by measuring serum interleukin (IL)-6 and cortisol concentrations, and the febrile response over time. A follow-up liver biopsy study was performed to determine kinetic differences in the expression of eight candidate hepatic genes between LPS dose groups using real-time RT-PCR. The initial time trail did not follow a linear dose response relationship with respect to the febrile and HPAA response to LPS challenge. Serum IL-6 concentrations increased in the two highest treatment groups but did not correlate with the observed febrile and HPAA response. The expression of Toll-like receptor 4, CD14, IL-6, tumor necrosis factor-alpha, IL-1beta, macrophage migration inhibitory factor, 11-beta-hydroxysteroid dehydrogenase (HSD), and tachykinin precursor 1 hepatic genes was dependent on both the dose and the kinetics of the response to LPS.