Differential acute phase immune responses by Angus and Romosinuano steers following an endotoxin challenge

Dietary L-carnitine supplementation modifies blood parameters of mid-lactating dairy cows during standardized lipopolysaccharide-induced inflammation

L-carnitine, available as feed additive, is essential for the beta-oxidation of free fatty acids in the mitochondrial matrix. It provides energy to immune cells and may positively impact the functionality of leukocytes during the acute phase response, a situation of high energy demand. To test this hypothesis, German Holstein cows were assigned to a control group (CON, n = 26) and an L-carnitine supplemented group (CAR, n = 27, rumen-protected L-carnitine product: 125 g/cow/d, corresponded to total L-carnitine intake: 25 g/cow/d, supplied with concentrate) and received an intravenous bolus injection of lipopolysaccharides (LPS, 0.5 µg/kg body weight, E. coli) on day 111 postpartum as a model of standardized systemic inflammation. Blood samples were collected from day 1 ante injectionem until day 14 post injectionem (pi), with frequent sampling through an indwelling venous catheter from 0.5 h pi to 12 h pi. All parameters of the white blood cell count responded significantly to LPS, while only a few parameters were affected by L-carnitine supplementation. The mean eosinophil count, as well as the percentage of basophils were significantly higher in CAR than in CON over time, which may be due to an increased membrane stability. However, phagocytosis and production of reactive oxygen species by leukocytes remained unchanged following L-carnitine supplementation. In conclusion, although supplementation with 25 g L-carnitine per cow and day resulted in increased proportions of specific leukocyte populations, it had only minor effects on the functional parameters studied in mid-lactating dairy cows during LPS-induced inflammation, and there was no evidence of direct improvement of immune functionality.

Plasma lipopolysaccharide elevations in cattle associated with early-stage infection by Fasciola hepatica

Fasciolosis is an endemic zoonotic parasitic disease with significant impacts on human health and both animal health and production. Early post-infection impacts on the host remain unclear. The objective of this study was to determine the changes, if any, to levels of endotoxin in cattle plasma in response to early-stage infection with Fasciola hepatica. Thirty-six (36) commercial bred cattle were experimentally infected with approximately 400 viable metacercariae. Plasma lipopolysaccharide (endotoxin) levels were examined on 24 occasions from 0 h before infection to 336 h after infection using the Limulus Amoebocyte Lysate chromogenic end point assay and compared with that of six (6) uninfected control animals. Peak lipopolysaccharide levels in infected animals were reached at 52 h after infection and returned to pre-infection levels at time 144 h after infection. Infected animals had significantly elevated lipopolysaccharide levels between 24 and 120 h after infection when compared to uninfected animals. The mean change in endotoxin units (EU)/mL over time after infection was statistically significant in infected animals. Elevations of lipopolysaccharide occurred in all infected animals suggesting a possible repeatable and titratable endotoxemia conducive to therapeutic agent model development.

Expression profiling of heat shock protein genes in whole blood of Romosinuano cattle breed

Background and Aim: Heat shock proteins are highly conserved proteins that work as molecular chaperones expressed in response to thermal stress. This study aimed to determine the expression profile of genes related to the heat stress response in whole blood obtained from the Romosinuano creole breed. Materials and Methods: Real-time polymerase chain reaction was performed to analyze the transcript of hsp90, hsp70, hsp60, and hsf1 in the whole blood of Romosinuano under different temperature-humidity indices (THIs). Results: The expression levels of the hsp70 and hsf1 genes at the high-THI level were higher (p = 0.0011 and p = 0.0003, respectively) than those at the low-THI level. In addition, no differences in the expression levels of the hsp60 and hsP90 genes were detected between the two THIs. Conclusion: The overexpression of hsf1 and hsp70 genes play an important role in protecting cells from damage induced by heat stress. Keywords: climate change, external environment, heat shock proteins, heat stress, mRNA, temperature-humidity index.

Expression profiling of heat shock protein genes in whole blood of Romosinuano cattle breed

Background and Aim

Heat shock proteins are highly conserved proteins that work as molecular chaperones expressed in response to thermal stress. This study aimed to determine the expression profile of genes related to the heat stress response in whole blood obtained from the Romosinuano creole breed.

Materials and Methods

Real-time polymerase chain reaction was performed to analyze the transcript of hsp90, hsp70, hsp60, and hsf1 in the whole blood of Romosinuano under different temperature-humidity indices (THIs).

Results

The expression levels of the hsp70 and hsf1 genes at the high-THI level were higher (p = 0.0011 and p = 0.0003, respectively) than those at the low-THI level. In addition, no differences in the expression levels of the hsp60 and hsP90 genes were detected between the two THIs.

Conclusion

The overexpression of hsf1 and hsp70 genes play an important role in protecting cells from damage induced by heat stress.

Acute phase proteins in cattle and swine: A review

The major acute phase proteins (APPs) in cattle are haptoglobin (Hp) and serum amyloid A (SAA), and in swine, are Hp, SAA, C-reactive protein (CRP), and Pig major acute phase protein (Pig-MAP). Many methodologic assays are presently available to measure these parameters, which are still being improved to increase their specificity, sensitivity, user-friendliness, and economic availability. In cattle, the main applications are the diagnosis and monitoring of frequent diseases such as mastitis and metritis in dairy cows and respiratory problems in young calves. In pigs, APPs are useful in the control of bacterial and viral infections, and they may be used at the slaughterhouse to monitor subclinical pathologies and improve food safety. The utility of APP in animal production must not be forgotten; optimization of protocols to improve performance, welfare, and nutrition may benefit from the use of APPs. Other sample types besides serum or plasma have potential uses; APP determination in milk is a powerful tool in the control of mastitis, saliva is a non-invasive sample type, and meat juice is easily obtained at the slaughterhouse. Increasing our knowledge of reference intervals and the influence of variables such as age, breed, sex, and the season is important. Finally, worldwide harmonization and standardization of analytical procedures will help to expand the use of APPs.

Sexual Dimorphic Innate Immune Response to a Viral-Bacterial Respiratory Disease Challenge in Beef Calves

The potential for sexually dimorphic innate immune responses to respiratory disease was evaluated, where eight steers and seven heifers (280 ± 4 kg) were subjected to a viral−bacterial respiratory disease challenge utilizing bovine herpesvirus-1 (BoHV-1; intranasal; 1 × 108 PFU/nostril) and Mannheimia haemolytica (MH; intratracheal; 1.3 × 107 CFU/head) administered 72 h later. Body temperature was lesser in heifers than steers (p < 0.01). There was a sex × time interaction (p = 0.05) for white blood cells where heifers had reduced concentrations compared with steers at −72 and 0 h but greater concentrations from 36 to 60 h post-MH. Concentrations of neutrophils were lesser in heifers compared to steers from 0 to 4 h, and from 8 to 12 h (p = 0.03). Lymphocytes were greater in heifers compared to steers at 12 h and from 36 to 60 h post-MH (p < 0.01). The neutrophil−lymphocyte ratio was lesser in heifers compared to steers from 2 to 24 h and at 48 h post-MH (p < 0.01). Monocytes were greater in heifers compared to steers from 24 to 60 h post-MH (p < 0.01), while eosinophils were greater in heifers compared to steers at 48 and 60 h (p < 0.01). Serum IL-4 was lesser in heifers compared to steers at 0 h and from 2 to 72 h post-MH challenge (p = 0.02). Non-esterified fatty acid concentrations were lesser (p < 0.01) in heifers compared to steers from 2 to 4 h post-MH challenge. Urea nitrogen concentrations were greater (p < 0.01) in heifers than steers at 36 h post-MH challenge. Data from this study reveal distinct differences in the acute phase response following a respiratory disease challenge where steers produced an early response, while the response in heifers appeared to be delayed.

Dietary zinc concentration and lipopolysaccharide injection affect circulating trace minerals, acute phase protein response, and behavior as evaluated by an ear-tag-based accelerometer in beef steers

To assess plasma trace mineral (TM) concentrations, the acute phase protein response, and behavior in response to a lipopolysaccharide (LPS) challenge, 96 Angus cross steers (average initial body weight [BW]: 285 ± 14.4 kg) were sorted into two groups by BW (heavy and light; n = 48/group), fitted with an ear-tag–based accelerometer (CowManager SensOor; Agis, Harmelen, Netherlands), and stagger started 14 d apart. Consecutive day BW was recorded to start the 24-d trial (days −1 and 0). Dietary treatments began on day 0: common diet with either 30 (Zn30) or 100 (Zn100) mg supplemental Zn/kg DM (ZnSO₄). On day 17, steers received one of the following injection treatments intravenously to complete the 2 × 3 factorial: 1) SALINE (~2–3 mL of physiological saline), 2) LOWLPS: 0.25 µg LPS/kg BW, or 3) HIGHLPS: 0.375 µg LPS/kg BW. Blood, rectal temperature (RT), and BW were recorded on day 16 (−24 h relative to injection), and BW was used to assign injection treatment. Approximately 6, 24 (day 18), and 48 (day 19) h after treatment, BW, RT, and blood were collected, and final BW recorded on day 24. Data were analyzed in Proc Mixed of SAS with fixed effects of diet, injection, diet × injection; for BW, RT, dry matter intake (DMI), plasma TM, and haptoglobin-repeated measures analysis were used to evaluate effects over time. Area under the curve analysis determined by GraphPad Prism was used for analysis of accelerometer data. Body weight was unaffected by diet or injection (P ≥ 0.16), but there was an injection × time effect for DMI and RT (P < 0.05), where DMI decreased in both LPS treatments on day 16, but recovered by day 17, and RT was increased in LPS treatments 6 h post-injection. Steers receiving LPS spent less time highly active and eating than SALINE (P < 0.01). Steers in HIGHLPS spent lesser time ruminating, followed by LOWLPS and then SALINE (P < 0.001). An injection × time effect (P < 0.001) for plasma Zn showed decreased concentrations within 6 h of injection and remained decreased through 24 h before recovering by 48 h. A tendency for a diet × time effect (P = 0.06) on plasma Zn suggests plasma Zn repletion occurred at a greater rate in Zn100 compared to Zn30. These results suggest that increased supplemental Zn may alter the rate of recovery of Zn status from an acute inflammatory event. Additionally, ear-tag–based accelerometers used in this study were effective at detecting sickness behavior in feedlot steers, and rumination may be more sensitive than other variables.

Comparative study of growth performance, nutrient digestibility, and ruminal and fecal bacterial community between yaks and cattle-yaks raised by stall-feeding

The experiment was conducted to compare the growth performance, rumen fermentation, nutrient digestibility, and ruminal and fecal bacterial community between yaks and cattle-yaks. Ten male yaks (36-month-old) were used as the yak (YAK) group and 10 male cattle-yaks with similar age were selected as the cattle-yak (CAY) group. All the animals were fed same ration and the experiment lasted for 60 days. The results showed that the average daily gain and dry matter intake of CAY group were higher (P < 0.05) than those of YAK group. The ruminal concentrations of total volatile fatty acids, acetate, and butyrate were higher (P < 0.05) in CAY group than those in YAK group. However, the neutral detergent fiber and acid detergent fiber digestibility exhibited an opposite between two groups. In the rumen, the relative abundances of Prevotella 1 and Prevotellaceae UCG-001 were higher (P < 0.05) and Succiniclasticum and Butyrivibrio 2 were lower (P < 0.05) in YAK group compared to CAY group. In the feces, the unclassified Lachnospiraceae, Lachnospiraceae NK4A136 group, and Lachnospiraceae AC2044 group were significantly enriched (P < 0.05) in YAK group, whereas the Ruminococcaceae UCG-010, Ruminococcaceae UCG-013, and Succiniclasticum were significantly enriched (P < 0.05) in CAY group. Overall, under the same diet, the yaks have higher fiber utilization and cattle-yaks have higher energy utilization.

Metabolomic Profiling of Bos taurus Beef, Dairy, and Crossbred Cattle: A Between-Breeds Meta-Analysis

Cattle breeds may differ substantially in their metabolism. However, the metabolomes of dairy and beef cattle are not well-known. Knowledge of breed-specific metabolic features is essential for biomarker identification and to adopt specific nutritional strategies. The muscle hypertrophy (mh), a beef cattle phenotype present in Asturiana de los Valles (AV) but absent in Asturiana de la Montaña (AM) and Holsteins, may underlie such differences. We compared the plasma metabolomes of Holstein, AV, AM, and crossbred cattle recipients selected for meta-analysis within an embryo transfer (ET) program. Blood samples were collected on day 0 (oestrus) and day 7 (prior to ET) (N = 234 samples × 2 days). Nuclear magnetic resonance quantified N = 36 metabolites in plasma, and more metabolic differences between breeds were found on day 0 (N = 19 regulated metabolites) than on day 7 (N = 5). AV and AM largely differed from Holstein cattle (N = 55 and 35 enriched metabolic pathways, respectively); however, AV and AM differed in N = 6 enriched pathways. Metabolic activity was higher in AV than in Holstein cattle, as explained in part by the mh phenotype. The metabolomic characterization of breeds facilitates biomarker research and helps to define the healthy ranges of metabolite concentrations.

Effect of bovine genotype on innate immune response of heifers to repeated lipopolysaccharide (LPS) administration

This pilot study provides a preliminary assessment of the impact of genotype on acute innate immune pro-inflammatory, metabolic and endocrine responses to repeated lipopolysaccharide (LPS) administered to growing heifers. Heifers (n = 4/genotype) were from unselected (stable milk yield since 1964, UH) or contemporary (CH) Holstein cows that differed in milk yield (6200 vs 11,100 kg milk/305 d) or from contemporary Black Angus (CA) cows bred to contemporary Red Angus bulls. Heifers were challenged with iv administration of 0.5 μg LPS/kg body weight on day 1 (Challenge 1) and d 5 (Challenge 2) of study to assess endotoxin tolerance. Plasma was collected at -1, -0.5, 0, 1, 2, 3, 4, 6, 8, and 24 h relative to each LPS administration. Rectal body temperature (BT) was measured before each blood sampling and at 5 and 7 h. Data were analyzed by repeated measures with sampling time as the repeated effect. Each genotype had at least one pro-inflammatory response that indicated it might have a more robust response than the other genotypes. The CH heifers had a greater TNF-α response, UH heifers had greater IL-6 and XO responses and CA heifers had greater BT and SAA response to LPS than the other genotypes. There was a genotype by time by interaction as cortisol peaked earlier in CH and UH than in CA heifers. Glucose response was less in CA and insulin response was greater in CH heifers. Endotoxin tolerance to LPS was evident as pro-inflammatory, cortisol, glucose and insulin responses were less during Challenge 2 than during Challenge 1. Differences among genotypes during Challenge 1 were eliminated during Challenge 2 except for the greater SAA response in CA heifers and indicate the potential for differential impacts of genotype on the development of endotoxin tolerance. Specific reasons for these effects of genotype are not clear from these data but the results support the hypothesis for differential innate immune signaling among these bovine genotypes.

Metabolomics Profiling of Serum and Urine in Three Beef Cattle Breeds Revealed Different Levels of Tolerance to Heat Stress

This study was to determine differences in the global metabolic profiles of serum and urine of Xuanhan yellow cattle, Simmental crossbred cattle (Simmental × Xuanhan yellow cattle), and cattle-yaks (Jersey × Maiwa yak) under heat stress (temperature-humidity index remained above 80 for 1 week). A total of 55 different metabolites associated with the three breeds were identified in the serum and urine samples by gas chromatography-mass spectrometry. The metabolic adaptations to heat stress are heterogeneous. Cattle-yaks mobilize a greater amount of body protein to release glucogenic amino acids to supply energy, whereas the tricarboxylic acid cycle is inhibited. Simmental crossbred cattle mobilize a greater amount of body fat to use free fatty acids as an energy source. In comparison with Simmental crossbred cattle and cattle-yaks, Xuanhan yellow cattle have higher glycolytic activity and possess a stronger antioxidant defense system and are, in conclusion, more adapted to hot and humid environments.

Evaluation of tropically adapted straightbred and crossbred beef cattle: Cortisol concentration and measures of temperament at weaning and transport

The objective of this research was to evaluate circulating concentrations of plasma cortisol and measures of temperament at weaning in calves (steers and heifers) and at transport in steers. Calves ( = 993) were produced from a 3-breed diallel mating design that included calves from 3 consecutive years. Breed types of calves were straightbred Angus (A), Brahman (B), and Romosinuano (R) and all F crossbred combinations (AB, BA, AR, RA, BR, and RB). At weaning (d 0) and at 24 and 72 h after weaning, blood was sampled from calves and the plasma was stored for later cortisol assay. Additionally, at each of these times, temperament was assessed as chute score, exit velocity, and pen score. About 1 mo later, steer calves ( = 471) were sampled before shipment, at arrival, and at 24 h, 72 h, 2 wk, and 4 wk after shipment (2,025 km; Brooksville, FL, to El Reno, OK). At each of these sampling times, blood was collected and plasma was stored for subsequent cortisol assay and temperament was assessed by measurement of exit velocity. At both weaning and transport, plasma concentrations of cortisol did not significantly differ ( > 0.05) among straightbreds or among crossbreds. Significant ( < 0.05) positive genetic effects were observed for plasma concentration of cortisol at weaning (heterosis for BA and direct Romosinuano effect) and transport (heterosis for RA, BR, and BA; direct Romosinuano effect; and maternal Angus effect). Assessment of temperament using the objective measurement of exit velocity or the subjective measures of chute score or pen score (1 [lowest] to 5 [highest excitability] scale, based on behavior in chute and behavior in pen with human observer, respectively) generally provided similar results: Brahman was higher than Brahman crosses, which were higher than Angus, Romosinuano, and their reciprocal crosses. For exit velocity, however, Brahman did not differ from Brahman crosses and Angus did not differ from Romosinuano or Brahman crosses. At transport, sire breed and dam breed affected exit velocity of steers, with higher ( < 0.05) estimates for Brahman than for Romosinuano or Angus. These data suggest that weaned calves and shipped steers of various breed types show a similar response to stressors in cortisol concentration. In contrast, in assessing temperament or behavioral response to humans, Romosinuano and Angus had better temperaments and were less excitable than Brahman.

Acute-phase proteins in pregnant goats: a longitudinal study

We documented changes in serum amyloid A (SAA) and haptoglobin (Hp) concentration in goats during pregnancy, as measured by competitive ELISAs. Fifteen does (pregnant group) and 20 castrated males (control group) were enrolled in the study. Blood samples were collected on the same day from all 35 goats, 7 times throughout the study period: at mating, then once every month, during the week preceding kidding, and 1 mo after kidding. Baseline SAA and Hp concentrations at mating were identical in the 2 groups. In the pregnant group, SAA concentration rose significantly in the second month and remained elevated until the end of pregnancy, with the peak concentration at kidding. In the control group, SAA concentration remained unchanged compared to the baseline concentration throughout the study. SAA concentration was significantly higher in the pregnant than control group only at the end of the fourth month of pregnancy and at kidding. Hp concentration did not change during pregnancy or between groups. SAA concentration at kidding was affected only by parity of does – it was highest in does in the third and fourth pregnancy and gradually lower in older does.

Health and growth of Finnish beef calves and the relation to acute phase response

Healthy, thriving calves are essential for beef calf production. We studied the health status and factors associated with the growth of beef calves in six cow-calf herds during the first month of the calves' lives and at weaning age (200 days). The six herds were visited three times, when calves were approximately 3 days, 16 days and 30 days of age. On each visit calves (n=37) were clinically examined, weighed or measured, blood samples were collected, faecal samples obtained and deep nasopharyngeal swabs were taken. Each blood sample was analysed for acute phase proteins (haptoglobin, serum amyloid-A, fibrinogen), total proteins and albumin, the faecal sample for intestinal tract pathogens (rotavirus, bovine coronavirus, enterotoxigenic Escherichia coli and Salmonella, oocysts of Eimeria coccidia and Cryptosporidium, and nematode eggs), and the nasopharyngeal swab for respiratory tract pathogens (bovine coronavirus (BCV), respiratory syncytial virus (RSV), bacteria and mycoplasma). Clinical diagnosis of respiratory tract disease, diarrhoea or umbilical disease was set at 15.0% for all the three consecutive examinations combined (n=107), but only few pathogens were detected from the samples. The increased levels of acute phase proteins were neither associated with any of the diseases nor with the pathogens. Random intercept linear models were used to explore factors affecting early (3-30 days) and long-term (3-200 days) growth, showing that calves with elevated serum amyloid-A concentrations at the age of 16 days had lower long-term growth. Increased albumin concentration at 30 days of age and higher parity of the dam increased early-term growth. The lack of association between a disease and the acute phase protein may stem from the low disease prevalence in the beef calves examined. The measurement of acute phase proteins of a young calf can help identify animals with possible future growth deficiencies, although the mechanisms through which the association between acute phase proteins and growth has yet to be explained.

Weaned pigs experimentally infected with Salmonella display sexually dimorphic innate immune responses without affecting pathogen colonization patterns. Transl Anim Sci 2017;1:69-76. [PMID: 31372597 PMCID: PMC6675027 DOI: 10.2527/tas2016.0008]

Sexually dimorphic innate immune responses have been observed in several species, but have not been studied in response to a live pathogen challenge in pigs. This study aimed to elucidate sexually dimorphic innate immune responses along with Salmonella translocation patterns in newly weaned pigs orally inoculated with Salmonella. Newly weaned pigs (n = 8 gilts and 12 barrows; 6.2 ± 0.2 kg BW) were obtained from a commercial swine facility and were maintained in an environmentally-controlled facility in individual pens equipped with feeders and nipple waterers. Pigs were allowed ad libitum access to a commercial non-medicated starter ration and water throughout the study. On d 12 post-weaning, pigs were anesthetized to allow placement of a temperature measuring device in the abdominal cavity for measurement of intraperitoneal temperature (TEMP). On d 17, pigs were anesthetized and fitted with indwelling jugular vein catheters. On the following day (d 18), pigs were orally inoculated with 4.7x10⁹Salmonella typhimurium. Blood samples were collected at 0.5-h intervals from -2 to 8 h, and at 8-h intervals from 8 to 72 h post-challenge. Whole blood was analyzed for complete blood cell counts. Serum was isolated for measurement of cortisol. Following collection of the 72 h sample, pigs were humanely euthanized and tissues were collected for Salmonella isolation. There was a sex × time interaction (P < 0.001) for TEMP such that gilts had a greater TEMP response to the Salmonella challenge compared to barrows. There was also a sex × time interaction (P = 0.03) for serum cortisol with gilts having decreased cortisol at 16 h yet greater cortisol at 32 h than barrows. Barrows had greater total white blood cells (17.8 vs. 16.2 ± 0.4 10³ cells/μL; P < 0.01; respectively) and neutrophils (7.8 vs. 6.1 ± 0.4 10³ cells/μL; P < 0.01; respectively) than gilts. However, gilts had greater lymphocytes (9.6 vs. 9.0 ± 0.2 10³ cells/μL; P = 0.05; respectively) than barrows. While immune parameters were influenced by sex, there was no effect of sex (P > 0.05) on Salmonella concentrations from fecal shedding 3 d post-inoculation in the cecum, mesenteric and subiliac lymph nodes, liver, spleen, gallbladder, or kidney tissues. These data demonstrate that weaned gilts appear to produce a stronger acute phase response to a Salmonella challenge compared to barrows, without affecting the tissue translocation or shedding of Salmonella.

Differential responsiveness of Holstein and Angus dermal fibroblasts to LPS challenge occurs without major differences in the methylome

BACKGROUND

We have previously found substantial animal-to-animal and age-dependent variation in the response of Holstein fibroblast cultures challenged with LPS. To expand on this finding, fibroblast cultures were established from dairy (Holstein) and beef (Angus) cattle and challenged with LPS to examine breed-dependent differences in the innate immune response. Global gene expression was measured by RNA-Seq, while an epigenetic basis for expression differences was examined by methylated CpG island recovery assay sequencing (MIRA-Seq) analysis.

RESULTS

The Holstein breed displayed a more robust response to LPS than the Angus breed based on RNA-Seq analysis of cultures challenged with LPS for 0, 2, and 8 h. Several immune-associated genes were expressed at greater levels (FDR < 0.05) in Holstein cultures including TLR4 at all time points and a number of pro-inflammatory genes such as IL8, CCL20, CCL5, and TNF following LPS exposure. Despite extensive breed differences in the transcriptome, MIRA-Seq unveiled relatively similar patterns of genome-wide DNA methylation between breeds, with an overall hypomethylation of gene promoters. However, by examining the genome in 3Kb windows, 49 regions of differential methylation were discovered between Holstein and Angus fibroblasts, and two of these regions fell within the promoter region (-2500 to +500 bp of the transcription start site) of the genes NTRK2 and ADAMTS5.

CONCLUSIONS

Fibroblasts isolated from Holstein cattle display a more robust response to LPS in comparison to cultures from Angus cattle. Different selection strategies and management practices exist between these two breeds that likely give rise to genetic and epigenetic factors contributing to the different immune response phenotypes.

Characterization of the contributions of Hp-MMP 9 to the serum acute phase protein response of lipopolysaccharide challenged calves

Background

Bovine respiratory disease (BRD) is a costly feature of modern cattle production. Early and accurate detection of BRD may prove useful in the successful management of this disease. The primary objective of the study was to define the time course of covalent complexes of neutrophil, haptoglobin (Hp) and matrix metalloproteinase 9 (Hp-MMP 9) in serum after intravenous lipopolysaccharide (LPS) in comparison to traditional markers. Our hypothesis was that serum concentrations of neutrophil Hp-MMP 9 provides information distinct from traditional acute phase protein markers. To characterize the neutrophil responses to lipopolysaccharide (E. coli; O111:B4; 2.5 μg/kg body weight), nine healthy, Jersey calves (65-82 days of age; 74.5 ± 13.1 kg) were challenged and physiologic parameters, peripheral blood cell counts and serum cortisol (C), Hp-MMP 9, Hp, alpha₁-acid glycoprotein (AGP), serum amyloid A (SAA) were obtained starting 24 hours before to 96 hours post-LPS challenge.

Results

Physiologic parameters (temperature, pulse, respiratory rate) and attitude assessed at each time point indicated that LPS challenge resulted in rapid onset of depression, tachypnea, leukopenia, neutropenia and lymphopenia within 1 hour. Serum C concentrations were significantly increased by 1 hour post-LPS. Serum Hp-MMP 9 complexes were detectable in serum by 0.5 hours and peaked at 16 h, serum total Hp remained <10 μg/mL until 8 hours post LPS infusion and were significantly greater than baseline by 12 hours post-LPS infusion. Serum amyloid A concentrations increased significantly by 8 hours post LPS. Serum concentrations of AGP increased significantly by 16 hours post LPS. Serum concentrations of Hp, SAA and AGP remained significantly greater than baseline out to 96 hours post-LPS. The total systemic exposure to traditional makers is significantly greater than from Hp-MMP 9

Conclusion

Using a well described model for acute phase protein responses, the data demonstrate that serum neutrophil Hp-MMP 9 complexes appear sooner and decline more rapidly than other acute phase proteins (APP). Since Hp-MMP9 is stored pre-formed, it provides information specifically addressing the LPS-induced activation of bovine neutrophils. Contributions of Hp-MMP 9 to the serum acute phase protein response may provide useful information, independent of hepatic responses, in diagnosis of acute inflammation.

Natural variations in the stress and acute phase responses of cattle

Activation of the innate immune system and acute phase response (APR) results in several responses that include fever, metabolic adaptations and changes in behavior. The APR can be modulated by many factors, with stress being the most common. An elevation of stress hormones for a short duration of time can be beneficial. However, elevation of stress hormones repeatedly or for an extended duration of time can be detrimental to the overall health and well-being of animals. The stress and APR responses can also be modulated by naturally-occurring variations, such as breed, gender, and temperament. These three natural variations modulate both of these responses, and can therefore modulate the ability of an animal to recover from a stressor or infection. Understanding that cattle have different immunological responses, based on naturally occurring variations such as these, may be the foundation of new studies on how to effectively manage cattle so that health is optimized and production is benefited.

Heat-tolerant versus heat-sensitive Bos taurus cattle: influence of air temperature and breed on the metabolic response to a provocative immune challenge

The response of the immune and stress systems have been assessed in response to a lipopolysaccharide (LPS) challenge, yet the role of metabolism in mediating energy requirements during the acute phase response has not been sufficiently studied. This study tested heat-tolerant (Romosinuano [RO]) and heat-sensitive (Angus [ANG]) Bos taurus breeds at different ambient temperatures (Ta) to determine differential metabolic responses to LPS challenge. Twenty-one heifers (ANG: n = 11, 306 ± 26 kg BW; RO: n = 10, 313 ± 32 kg BW) were housed in stanchions in 4 temperature-controlled chambers. Initially, Ta in all 4 chambers was cycling at thermoneutrality (TN; 18.5°C-23.5°C) for a 1-wk adjustment period, followed by an increase in 2 chambers to cycling heat stress (HS; 24°C-38°C) for 2 wk. Five ANG and 5 RO heifers were housed at TN, whereas 6 ANG and 5 RO heifers were housed at HS. On day 19, heifers were fitted with jugular catheters. On day 20, heifers were challenged with LPS (0.5 μg/kg BW; 0 h), and blood samples were collected from -2 to 8 h and at 24 h relative to LPS challenge. Serum was analyzed for glucose, insulin, and NEFA concentrations. In addition, feed intake was measured 3 d before and on the day of the challenge. Feed intake decreased over time (P < 0.001) and was decreased in heifers housed at HS compared with heifers housed at TN (P = 0.013). Glucose concentrations before LPS challenge were greater in RO (P = 0.01) than in ANG heifers and greater in TN-housed heifers (P = 0.02) than in HS heifers. Glucose after LPS challenge initially increased before decreasing below baseline concentrations (P < 0.01) in all heifers. In addition, there was a breed by Ta interaction (P < 0.004), such that HS decreased glucose concentrations in ANG heifers compared with ANG heifers housed at TN (P < 0.001), whereas HS did not affect glucose concentrations after LPS challenge in RO heifers (P = 0.941). Nonesterified fatty acid concentrations before LPS challenge were not affected by breed (P = 0.37) or Ta (P = 0.60). Although NEFA concentration after LPS challenge was unaffected by Ta (P = 0.78), there tended to be a breed by Ta interaction (P = 0.07) such that, when housed at HS, RO heifers had greater serum NEFA concentrations after LPS challenge than ANG heifers (P = 0.009). Insulin concentration before LPS challenge was greater in RO heifers than in ANG heifers (P < 0.01). Insulin after LPS challenge increased (P < 0.01), with RO heifers producing a greater insulin response than ANG heifers (P < 0.01). These data suggest that HS decreases the metabolic response of heat-sensitive ANG heifers in response to LPS challenge, thus providing physiological evidence that may explain differences observed in the acute phase response between heat-sensitive ANG and heat-tolerant RO cattle breeds.

Heat-tolerant versus heat-sensitive Bos taurus cattle: influence of air temperature and breed on the acute phase response to a provocative immune challenge

The difference in the acute phase response of a heat-tolerant and a heat-sensitive Bos taurus breed to a lipopolysaccharide (LPS) challenge when housed at different air temperatures (Ta) was studied. Angus (ANG; heat-sensitive; n = 11; 306 ± 26 kg BW) and Romosinuano (RO; heat-tolerant; n = 10; 313 ± 32 kg BW) heifers were transported from the USDA Agricultural Research Service SubTropical Agricultural Research Station in Florida to the Brody Environmental Chambers at the University of Missouri, Columbia. Heifers were housed in stanchions in 4 temperature-controlled environmental chambers. Initially, Ta in the 4 chambers was cycling at thermoneutrality (TN; 18.5°C-23.5°C) for a 1-wk adjustment period, followed by an increase in 2 of the 4 chambers to cycling heat stress (HS; 24°C-38°C) for 2 wk. On day 19, heifers were fitted with jugular catheters and rectal temperature (RT) recording devices. On day 20, heifers were challenged with LPS (0.5 μg/kg BW; 0 h), sickness behavior scores (SBSs) were recorded, and blood samples were collected at 0.5-h intervals from -2 to 8 h and again at 24 h relative to LPS challenge at 0 h. Serum was isolated and stored at -80°C until analyzed for cortisol and cytokine concentrations. A breed by Ta interaction (P < 0.001) was observed for RT such that the post-LPS average RT in RO heifers housed at TN was lower than the RT of all other treatment groups (P < 0.001), whereas ANG heifers housed at HS had greater post-LPS average RT than all other treatment groups (P < 0.001). In response to LPS, HS increased SBS after LPS in RO heifers compared to RO heifers housed at TN (P < 0.001), whereas HS decreased SBS after LPS in ANG heifers compared to ANG heifers housed at TN (P = 0.014). The cortisol response to LPS was greater in TN than in HS heifers (P < 0.01) and was also greater in RO than in ANG heifers (P = 0.03). A breed by Ta interaction (P < 0.01) was observed for tumor necrosis factor-α (TNF-α) concentration such that HS increased post-LPS serum concentrations of TNF-α in ANG heifers compared to ANG heifers housed at TN (P = 0.041), whereas HS decreased post-LPS concentrations of TNF-α in RO heifers compared to RO heifers housed at TN (P = 0.008). A tendency (P < 0.06) was observed for a breed by Ta interaction for IL-6 concentrations such that RO heifers had greater post-LPS concentrations of IL-6 than ANG heifers when housed at HS (P = 0.020). A breed by Ta interaction was observed for interferon-γ (IFN-γ; P < 0.01) concentrations such that HS decreased post-LPS concentrations of IFN-γ in ANG heifers compared to ANG heifers housed at TN (P < 0.001), and HS increased post-LPS concentrations of IFN-γ in RO heifers compared to RO heifers housed at TN (P = 0.017). These data indicate differences in the acute phase response between the heat-tolerant RO and heat-sensitive ANG heifers under different Ta which may aid in elucidating differences in productivity, disease resistance, and longevity among cattle breeds.

Analysis of conservation priorities of Iberoamerican cattle based on autosomal microsatellite markers

Background

Determining the value of livestock breeds is essential to define conservation priorities, manage genetic diversity and allocate funds. Within- and between-breed genetic diversity need to be assessed to preserve the highest intra-specific variability. Information on genetic diversity and risk status is still lacking for many Creole cattle breeds from the Americas, despite their distinct evolutionary trajectories and adaptation to extreme environmental conditions.

Methods

A comprehensive genetic analysis of 67 Iberoamerican cattle breeds was carried out with 19 FAO-recommended microsatellites to assess conservation priorities. Contributions to global diversity were investigated using alternative methods, with different weights given to the within- and between-breed components of genetic diversity. Information on Iberoamerican plus 15 worldwide cattle breeds was used to investigate the contribution of geographical breed groups to global genetic diversity.

Results

Overall, Creole cattle breeds showed a high level of genetic diversity with the highest level found in breeds admixed with zebu cattle, which were clearly differentiated from all other breeds. Within-breed kinships revealed seven highly inbred Creole breeds for which measures are needed to avoid further genetic erosion. However, if contribution to heterozygosity was the only criterion considered, some of these breeds had the lowest priority for conservation decisions. The Weitzman approach prioritized highly differentiated breeds, such as Guabalá, Romosinuano, Cr. Patagonico, Siboney and Caracú, while kinship-based methods prioritized mainly zebu-related breeds. With the combined approaches, breed ranking depended on the weights given to the within- and between-breed components of diversity. Overall, the Creole groups of breeds were generally assigned a higher priority for conservation than the European groups of breeds.

Conclusions

Conservation priorities differed significantly according to the weight given to within- and between-breed genetic diversity. Thus, when establishing conservation programs, it is necessary to also take into account other features. Creole cattle and local isolated breeds retain a high level of genetic diversity. The development of sustainable breeding and crossbreeding programs for Creole breeds, and the added value resulting from their products should be taken into consideration to ensure their long-term survival.

Yeast cell wall supplementation alters aspects of the physiological and acute phase responses of crossbred heifers to an endotoxin challenge

A study was conducted to determine the effect of feeding yeast cell wall (YCW) products on the physiological and acute phase responses of crossbred, newly-received feedlot heifers to an endotoxin challenge. Heifers (n = 24; 219 ± 2.4 kg) were separated into treatment groups receiving either a control diet (n = 8), YCW-A (2.5 g/heifer/d; n = 8) or YCW-C (2.5 g/heifer/d; n = 8) and were fed for 52 d. On d 37 heifers were challenged i.v. with LPS (0.5 µg/kg body mass) and blood samples were collected from -2 h to 8 h and again at 24 h relative to LPS challenge. There was an increase in vaginal temperature in all heifers post-LPS, with YCW-C maintaining a lower vaginal temperature post-LPS than control and YCW-A heifers. Sickness behavior scores increased post-LPS in all heifers, but were not affected by treatment. Cortisol concentrations were greatest in control heifers post-LPS compared with YCW-A or YCW-C heifers. Concentrations of IFN-γ and TNF-α increased post-LPS, but were not affected by treatment. Serum IL-6 concentrations increased post-LPS and were greater in control heifers than YCW-A and YCW-C heifers. These data indicate that YCW supplementation can decrease the physiological and acute phase responses of newly-received heifers following an endotoxin challenge.

Molecular genetics of the adrenocortical axis and breeding for robustness

The concept of robustness refers to the combination of a high production potential and a low sensitivity to environmental perturbations. The importance of robustness-related traits in breeding objectives is progressively increasing toward the production of animals with a high production level in a wide range of climatic conditions and production systems, together with a high level of animal welfare. Current strategies to increase robustness include selection for "functional traits," such as skeletal and cardiovascular integrity, disease resistance, and mortality at various stages. It is also possible to use global evaluation of sensitivity to the environment (eg reaction norm analysis or canalization), but these techniques are difficult to implement in practice. The glucocorticoid hormones released by the adrenal cortex exert a wide range of effects on metabolism, the cardiovascular system, inflammatory processes, and brain function, for example. Protein catabolism toward energy production and storage (lipids and glycogen) supports their pivotal role in stress responses aiming at the adaptation and survival of individuals under strong environmental pressure. Large individual variations have been described in adrenocortical axis activity, with important physiopathological consequences. In terms of animal production, higher cortisol levels have negative effects on growth rate and feed efficiency and increase the fat:lean ratio of carcasses. On the contrary, cortisol has positive effects on functional traits and adaptation. Intense selection for lean tissue growth and more generally high protein output during the past decades has concomitantly reduced cortisol production, which may be responsible for the negative effects of selection on functional traits. In this paper, we review experimental evidence suggesting that the balance between production and functional traits was modified in favor of improved robustness by selecting animals with higher adrenocortical axis activity, as well as the molecular genetic tools that can be used to fine-tune this objective.

Influence of environmental temperature on the physiological, endocrine, and immune responses in livestock exposed to a provocative immune challenge

Although livestock experience many stressors throughout their life, one of the most commonly experienced, and most difficult to control, is stress caused by fluctuations in environmental temperatures that extend beyond the thermoneutral (TN) zone for an animal. In swine, cold stress has long been recognized as a main cause of neonatal morbidity and mortality. A possible explanation for this increased morbidity and mortality may be related to their inability to generate a febrile response. Previously, we reported that the acute phase immune response, including the generation of fever, after exposure to lipopolysaccharide (LPS; Escherichia coli O111: B4; Sigma-Aldrich, St Louis, MO, USA) is substantially altered in neonatal pigs maintained in a cold environment (ie, 18°C). Neonatal pigs that were maintained in a cold environment and administered LPS experienced a period of hypothermia coupled with altered endocrine and proinflammatory cytokine responses that could prove detrimental. In cattle, we previously reported differences in the acute phase immune response of two diverse breeds of Bos taurus cattle (Angus and Romosinuano) when maintained under TN conditions and exposed to LPS. More recently we have reported that differences in the stress and immune responses of Angus and Romosinuano heifers varies, depending on whether the cattle were housed at either TN or heat stress air temperatures. Our data clearly show that even intermittent periods of heat stress similar to that experienced in production environments can have significant effects on the stress and innate immune responses of cattle. Understanding the effect of thermal stress on livestock is critical to developing and implementing alternative management practices to improve their overall health and well-being.