Plasma haptoglobin concentration in swine after challenge with Streptococcus suis

Increased Dietary Trp, Thr, and Met Supplementation Improves Performance, Health, and Protein Metabolism of Weaned Piglets under Mixed Management and Poor Housing Conditions

A sanitary challenge was carried out to induce suboptimal herd health while investigating the effect of amino acids supplementation on piglet responses. Weaned piglets of high sanitary status (6.33 ± 0.91 kg of BW) were distributed in a 2 × 2 factorial arrangement into two similar facilities with contrasting sanitary conditions and two different diets. Our results suggest that increased Trp, Thr, and Met dietary supplementation could support the immune systems of piglets under a sanitary challenge. In this manner, AA+ supplementation improved the performance and metabolism of piglets under mixed management and poor sanitary conditions. No major temporal microbiome changes were associated with differences in performance regardless of sanitary conditions or diets. Since piglets often become mixed in multiple-site production systems and facility hygiene is also often neglected, this study suggests that increased Trp, Thr, and Met (AA+) dietary supplementation could contribute to mitigating the side effects of these harmful risk factors in modern pig farms.

A critical review on experimental Streptococcus suis infection in pigs with a focus on clinical monitoring and refinement strategies

Streptococcus suis (S. suis) is a major pig pathogen worldwide with zoonotic potential. Though different research groups have contributed to a better understanding of the pathogenesis of S. suis infections in recent years, there are still numerous neglected research topics requiring animal infection trials. Of note, animal experiments are crucial to develop a cross-protective vaccine which is highly needed in the field. Due to the severe clinical signs associated with S. suis pathologies such as meningitis and arthritis, implementation of refinement is very important to reduce pain and distress of experimentally infected pigs. This review highlights the great diversity of clinical signs and courses of disease after experimental S. suis pig infections. We review clinical read out parameters and refinement strategies in experimental S. suis pig infections published between 2000 and 2021. Currently, substantial differences exist in describing clinical monitoring and humane endpoints. Most of the reviewed studies set the body temperature threshold of fever as high as 40.5°C. Monitoring intervals vary mainly between daily, twice a day and three times a day. Only a few studies apply scoring systems. Published scoring systems are inconsistent in their inclusion of parameters such as body temperature, feeding behavior, and respiratory signs. Locomotion and central nervous system signs are more common clinical scoring parameters in different studies by various research groups. As the heterogenicity in clinical monitoring limits the comparability between studies we hope to initiate a discussion with this review leading to an agreement on clinical read out parameters and monitoring intervals among S. suis research groups.

Different genotype and a liquid whey-supplemented diet influence the resilience of pigs through immune-modulation and anti-inflammatory response

This study evaluated (i) whether weight gain and levels of inflammatory and immune markers including white blood cells (WBC), serum haptoglobin, C-reactive protein, albumin, and globulin fractions change between the Nero Siciliano pig breed and the crossbreed Landrace x Large White (LxLW) reared under the same environmental and farming conditions; and (ii) whether a liquid whey diet supplementation affects the investigated parameters in both genotypes. In this study, 10 crossbreed LxLW and 10 Nero Siciliano pigs were given control feed, representing the control groups (CTRC and CTRNS), whereas 10 crossbreed LxLW and 10 Nero Siciliano pigs were given control feed supplemented with liquid whey for 2 months, representing the experimental groups (WC and WNS). From each pig, body weight and blood were collected before experimental diet supplementation (T0), and one (T1) and two (T2) months after the start of the diet supplemented with whey. The white blood cell count (WBC), serum haptoglobin, C-reactive protein, total proteins, albumin and globulin fraction concentration were assessed. Two-way analysis of variance showed an increasing trend of body weight both in the control and experimental groups of the two pig genotypes throughout the monitoring period (p < 0.01) without a significant effect of genotype and diet (p > 0.05). The concentration of haptoglobin, β1- and β2-globulins was affected by pig genotype, diet supplementation, and time (p < 0.01). The values of WBC, C-reactive protein, albumin, α-globulins, and A/G ratio were affected by diet supplementation (p < 0.01) and time (p < 0.01) without an influence of genotype (p > 0.05). Nero Siciliano pigs showed lower levels of haptoglobin, β1-globulin, and β2-globulin compared to crossbreed LxLW. Nero Siciliano pigs and crossbred LxLW fed with liquid whey showed lower levels of WBC, haptoglobin, C-reactive protein, α-, β1-, and β2-globulins and higher values of albumin compared to control groups. The results reinforced the hypothesis that autochthonous breeds possess higher resilience to farming conditions when compared to allochthonous breeds. Moreover, an immune-modulatory and an anti-inflammatory power of liquid whey dietary supplementation is suggested probably thanks to its content in natural bioactive substances including anti-inflammatory cytokines and anti-oxidative factors.

Systematic review of animal-based indicators to measure thermal, social, and immune-related stress in pigs

The intense nature of pig production has increased the animals’ exposure to stressful conditions, which may be detrimental to their welfare and productivity. Some of the most common sources of stress in pigs are extreme thermal conditions (thermal stress), density and mixing during housing (social stress), or exposure to pathogens and other microorganisms that may challenge their immune system (immune-related stress). The stress response can be monitored based on the animals’ coping mechanisms, as a result of specific environmental, social, and health conditions. These animal-based indicators may support decision making to maintain animal welfare and productivity. The present study aimed to systematically review animal-based indicators of social, thermal, and immune-related stresses in farmed pigs, and the methods used to monitor them. Peer-reviewed scientific literature related to pig production was collected using three online search engines: ScienceDirect, Scopus, and PubMed. The manuscripts selected were grouped based on the indicators measured during the study. According to our results, body temperature measured with a rectal thermometer was the most commonly utilized method for the evaluation of thermal stress in pigs (87.62%), as described in 144 studies. Of the 197 studies that evaluated social stress, aggressive behavior was the most frequently-used indicator (81.81%). Of the 535 publications examined regarding immune-related stress, cytokine concentration in blood samples was the most widely used indicator (80.1%). Information about the methods used to measure animal-based indicators is discussed in terms of validity, reliability, and feasibility. Additionally, the introduction and wide spreading of alternative, less invasive methods with which to measure animal-based indicators, such as cortisol in saliva, skin temperature and respiratory rate via infrared thermography, and various animal welfare threats via vocalization analysis are highlighted. The information reviewed was used to discuss the feasible and most reliable methods with which to monitor the impact of relevant stressors commonly presented by intense production systems on the welfare of farmed pigs.

The Effect of the Repair of Induced Articular Cartilage Defects in Pigs Using Calcium Phosphate Cement with Aminoacids on the Concentrations of Selected Inflammatory Markers and Serum Enzyme Activities

The repair of articular cartilage defects is an intensively developing area of research. Severe inflammatory reactions after surgical interventions on bones or their structures may lead to changes of bone or joint asymmetry. In laboratory diagnostics, some inflammatory biomarkers and serum enzymes are available for the evaluation of these inflammatory processes. A general understanding of inflammatory responses following the repair of cartilage defects is still lacking. The aim of this study was to describe the alterations in the values of five inflammatory markers and the activities of several enzymes in seven 5-month-old pigs within the first 30 days following the restoration of induced articular cartilage defects using the tetracalcium phosphate/nanomoneite cement powder enriched with amino acids (CAL). The reconstruction of surgically induced defects was accompanied by a significant increase of serum amyloid A (SAA, p < 0.05), haptoglobin (Hp, p < 0.001), C-reactive protein (CRP, p < 0.01), and pig major acute phase protein (pig-MAP, p < 0.001). Their concentrations decreased gradually within one-month post-surgery, the values recorded at the end of this period were higher than those obtained prior to surgery. The concentrations of α1-acid glycoprotein (AGP) showed no significant changes during the evaluated period. Alterations were also found in the enzyme activities of creatine kinase (p < 0.05), lactate-dehydrogenase and alkaline phosphatase (p < 0.01). These findings suggest that SAA, Hp, CRP and pig-MAP might be applicable biomarkers of acute phase response for the monitoring of postoperative period.

Serum amyloid A (SAA) mRNA expression in chicken and quails in response to bacterial stress

Monitoring of acute phase proteins such as serum amyloid A at gene expression level may provide quick information about immune status of the host and its susceptibility towards common infections. Present study was carried out to evaluate and compare the mRNA expression of SAA gene in Rhode Island Red chicken (RIR) and Japanese quails using real time PCR analysis in response to inactivated Salmonella gallinarum culture. The results showed that expression of SAA gene was approximately 17-33 folds higher in case of birds administered with bacterial culture when compared to un-inoculated controls and expression was higher and quicker in case of quails than RIR chicken. The SAA genes from chicken and quail were cloned and upon sequence analysis it was observed that deduced amino acid sequence of SAA from chicken and quails were having approximately seven percent variation which might have significance in function of this protein in these species.

Dietary plant extracts alleviate diarrhea and alter immune responses of weaned pigs experimentally infected with a pathogenic Escherichia coli

A study was conducted to evaluate the effects of 3 different plant extracts on diarrhea, immune response, intestinal morphology, and growth performance of weaned pigs experimentally infected with a pathogenic F-18 Escherichia coli (E. coli). Sixty-four weaned pigs (6.3±0.2 kg BW, and 21 d old) were housed in individual pens in disease containment chambers for 15 d: 4 d before and 11 d after the first inoculation (d 0). Treatments were in a 2×4 factorial arrangement: with or without an F-18 E. coli challenge (toxins: heat-labile toxin, heat-stable toxin b, and Shiga-like toxin 2; 10(10) cfu/3 mL oral dose; daily for 3 d from d 0) and 4 diets [a nursery basal diet (CON) or 10 ppm of capsicum oleoresin, garlic botanical, or turmeric oleoresin]. The growth performance was measured on d 0 to 5, 5 to 11, and 0 to 11. Diarrhea score (1, normal, to 5, watery diarrhea) was recorded for each pig daily. Frequency of diarrhea was the percentage of pig days with a diarrhea score of 3 or greater. Blood was collected on d 0, 5, and 11 to measure total and differential white blood cell counts and serum tumor necrosis factor (TNF)-α, IL-10, transforming growth factor (TGF)-β, C-reactive protein, and haptoglobin. On d 5 and 11, half of the pigs were euthanized to measure villi height and crypt depth of the small intestine and macrophage and neutrophil number in the ileum. The E. coli infection increased (P<0.05) diarrhea score, frequency of diarrhea, white blood cell counts, serum TNF-α and haptoglobin, and ileal macrophages and neutrophils but reduced (P<0.05) villi height and the ratio of villi height to crypt depth of the small intestine on d 5. In the challenged group, feeding plant extracts reduced (P<0.05) average diarrhea score from d 0 to 2 and d 6 to 11 and frequency of diarrhea and decreased (P<0.05) TNF-α and haptoglobin on d 5, white blood cell counts and neutrophils on d 11, and ileal macrophages and neutrophils on d 5. Feeding plant extracts increased (P<0.05) ileal villi height on d 5 but did not affect growth performance compared with the CON. In the sham group, feeding plant extract also reduced (P<0.05) diarrhea score, frequency of diarrhea, and ileal macrophages compared with the CON. In conclusion, the 3 plant extracts tested reduced diarrhea and inflammation caused by E. coli infection, which may be beneficial to pig health.

Effects of different antimicrobial treatments on serum acute phase responses and leucocyte counts in pigs after a primary and a secondary challenge infection with Actinobacillus pleuropneumoniae

The susceptibility to an initial challenge and a re-challenge inoculation with Actinobacillus pleuropneumoniae was analysed in pigs that were treated with antimicrobials of different efficacies following the first exposure to A pleuropneumoniae. In brief, 30 nine-week-old specific pathogen-free pigs were allocated to five groups of six. After acclimatisation, four groups were inoculated with A pleuropneumoniae serotype 2. At the onset of clinical signs, three of the groups of pigs were treated with enrofloxacin, tetracycline or penicillin. A fourth group served as the inoculated control and the fifth group as a control group that had not been inoculated. On day 28, all five groups were re-challenged with the same strain of A pleuropneumoniae serotype 2 as had been used in the first inoculation. No treatments were carried out at this time. The acute phase responses and differential leucocyte counts were monitored in detail after both inoculations. Leucocytosis and acute phase responses in the forms of serum amyloid A, pig-major acute phase protein and haptoglobin were recorded in all of the inoculated groups after the onset of clinical signs following the first inoculation. A porcine mannan-binding lectin-A response was less evident in the pigs. Acute phase responses resembling those of the first inoculation were observed in the pigs that had not previously been inoculated and in the pigs treated with enrofloxacin. Acute phase responses were not recorded in the other three groups, where the pigs had seroconverted to A pleuropneumoniae serotype 2 following the first inoculation.

Effects of feeding diets containing bacitracin methylene disalicylate to heat-stressed finishing pigs

The objective of this study was to evaluate the effects of heat stress and dietary bacitracin methylene disalicylate (BMD) on growth performance, carcass characteristics, and immunological responses in finishing pigs. Four groups of 32 finishing pigs (n = 128) with initial BW between 80 to 90 kg were used. Pigs were fed a corn-soybean meal-distillers grains-based control or BMD (31.5 mg/kg) diet for a 14-d adaptation period at the thermal neutral temperature (23°C), and continued to be fed their respective diets when exposed to a constant temperature (23°C) or a cyclical heat stress environment (37°C from 1000 to 1900 h and 27°C from 1900 to 1000 h) for a 28-d experimental period. Each group of pigs was housed in 4 rooms, with 2 pens/room and 4 pigs/pen. Saliva samples from each pig were collected on d -1 (initial baseline), 1, 13, and 27 for cortisol analysis. Concentrations of haptoglobin, IL-1β, and tumor necrosis factor-α were determined in serum samples on d -1, 1, 13, and 27. Pigs exposed to heat stress had 31% less ADG (P < 0.001), 23% less ADFI (P < 0.001), 9% less G:F (P < 0.001), and 34% greater average daily water intake (P = 0.03) than those in the non-heat-stress conditions. Dietary BMD tended to reduce ADG (P < 0.07) compared with the control (0.66 vs. 0.73 kg/d, respectively). Heat stress increased (P < 0.05) saliva cortisol on d 1, but no effects were observed on subsequent days. Serum haptoglobin concentrations were greater (P < 0.05) in heat-stressed pigs on d 1, and concentrations tended to remain greater (P < 0.1) on d 13. Pigs fed the BMD diet tended to have a longer villus height (P = 0.07) in the duodenum and greater crypt depths in the duodenum (P = 0.09) and jejunum (P = 0.07). Heat-stressed pigs tended to have a decreased proportion of propionate (P = 0.08), greater acetate:propionate (P = 0.08), and a reduced proportion of valerate (P = 0.02) in the cecum. These results indicate that BMD did not counteract the negative effects of heat stress on growth performance, but BMD appears to increase villus height and crypt depth in the duodenum. Furthermore, heat stress appears to alter VFA production in finishing pigs.

Response of swine spleen to Streptococcus suis infection revealed by transcription analysis

Astract

Acute phase response in porcine reproductive and respiratory syndrome virus infection

This study was focused on the changes observed in the serum concentration of haptoglobin (Hp), C-reactive protein (CRP), serum amyloid A (SAA) and Pig-major acute protein (Pig-MAP), during experimental porcine reproductive and respiratory syndrome virus (PRRSV) infection and in their relationship with the expression of interleukin 1β (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α). Hp and Pig-MAP serum levels were increased at 10 dpi, but CRP and SAA showed a delayed and highly variable increase. All three proinflammatory cytokines were poorly expressed, and only a mild increase in IL-1β was observed at 7 dpi. The increased expression of Hp coincided with the light enhancement observed in both IL-6 and TNF-α, and might be related with an increased expression of IL-10. The low expression of TNF-α might point to a possible mechanism of viral evasion of host-immune response. This issue and the delayed expression of CRP and SAA should be taken into account in future studies about modulation of the immune response by PRRSV infection.

Meat juice: An alternative matrix for assessing animal health by measuring acute phase proteins. Correlations of pig-MAP and haptoglobin concentrations in pig meat juice and plasma

Quantification of acute phase proteins (APPs) in blood can be used for monitoring animal health and welfare on farms, and could be also of interest for the detection of diseased animals during the meat inspection process. However serum or plasma is not always available for end-point analysis at slaughter. Meat juice might provide an adequate, alternative matrix that can be easily obtained for post-mortem analysis at abattoirs. The concentrations of pig Major Acute phase Protein (pig-MAP) and haptoglobin, two of the main APPs in pigs, were determined in approximately 300 paired samples of plasma and meat juice from the diaphragm (pars costalis), obtained after freezing and thawing the muscle. APPs concentrations in meat juice were closely correlated to those in plasma (r=0.695 for haptoglobin, r=0.858 for pig-MAP, p<0.001). These results open new possibilities for the assessment of animal health in pig production, with implications for food safety and meat quality.

Expression levels of immune markers in Actinobacillus pleuropneumoniae infected pigs and their relation to breed and clinical symptoms

Background

In pigs little is known about the role of innate immune defence in bacterial infections of the respiratory tract, despite their major role in pig production. In the present study we characterized and compared in vitro and in vivo activation of immune markers of different pig breeds 7 days before, and 4 and 21 days after an experimental aerosol infection with Actinobacillus (A.) pleuropneumoniae.

Results

In vitro stimulation of bronchoalveolar lavage fluid (BALF) and blood leukocytes with A. pleuropneumoniae, Streptococcus suis, PMA and LPS led to production of different amounts of H₂O₂, NO and TNF-α, depending on the stimulus, individual, breed and time of infection. Generally, significant responses to in vitro stimulation were observed only in blood leukocytes, whereas the alveolar macrophages showed a high basal activation. In addition, the production of haptoglobin and cytokines (TNF-α, IFN-γ and IL-10) in vivo was measured in plasma and BALF. Plasma haptoglobin levels mirrored the clinical manifestations at 4 days post-infection. In plasma and BALF TNF-α could not be detected, whereas variable levels of IFN-γ were found at pre- and post-infection times. IL-10 was found in some plasma but in none of the BALF samples. The different expression levels in individuals within the breeds correlated for some markers with the severity of clinical manifestations, e.g. H₂O_2, plasma haptoglobin and BALF IFN-γ for German Landrace pigs.

Conclusion

Our findings revealed differences in the activation of the immune markers with respect to infection time, individuals and breeds. Moreover, results showed different correlation grades between the immune markers produced in vitro or in vivo and the clinical manifestations. Further analyses will have to show whether these markers may serve as correlates of protection against porcine respiratory infections.

The effect of sanitary status degradation and dietary tryptophan content on growth rate and tryptophan metabolism in weaning pigs

Health degradation modifies Trp metabolism through induction of Trp catabolism. This could limit the amount of Trp available for growth. The aims of the present experiment were to investigate the effects of a low grade inflammation and dietary Trp on growth and Trp metabolism. Eighty weaned pigs were assigned to 4 experimental treatments according to a 2 x 2 factorial arrangement: 2 sanitary statuses x 2 dietary Trp contents. The Trp content was deficient (low-Trp: 2.4 and 1.9 g of Trp/kg of the phase I and phase II diets, respectively) or adequate (high-Trp: 2.9 and 2.4 g of Trp/kg of the phase I and phase II diets, respectively). A low grade inflammatory response was induced by housing pigs in unsanitary environment, whereas control pigs were housed in good sanitary conditions. Pigs were not fed ad libitum to avoid feed refusals. Growth performance was calculated 3, 5, and 7 wk after weaning. Blood was sampled 12, 33, and 47 d after weaning for the determination of plasma concentrations of Trp and related metabolites, kynurenine and pyridoxal-5-phosphate. The interaction between sanitary status and dietary Trp was not statistically significant in all measured criteria. Pigs kept in poor sanitary conditions grew slower (P < 0.001) during the entire experimental period and had greater plasma concentrations of haptoglobin (P < 0.001) than pigs housed in good sanitary conditions. Pigs housed in poor sanitary conditions had also decreased Trp plasma concentrations (P < 0.001), but plasma kynurenine concentrations were not affected. Our results indicated that a moderate inflammatory response was obtained by degrading the sanitary quality of environment. Additionally, poor sanitary conditions modified Trp metabolism, indicating that the amount of Trp available for growth and other metabolic functions might be reduced.

Relationship between serum acute phase protein concentrations and lesions in finishing pigs

To establish the relationship between serum levels of three acute phase proteins, haptoglobin (Hp), C-reactive protein (CRP) and serum amyloid A (SAA), and the occurrence and severity of lesions at slaughter, a study was carried out using 70 fattening pigs from a finishing unit. Pigs were divided into three groups: Group 1 (25 pigs with clinical signs of disease), Group 2 (25 apparently healthy pigs with lesions at slaughter) and Group 3 (20 apparently healthy pigs with no lesions at slaughter). Serum levels of CRP, SAA and Hp were significantly higher in pigs with clinical signs of disease than in apparently healthy animals. Additionally, in apparently healthy pigs, serum levels of Hp and CRP were significantly higher in animals with lesions than those without lesions. The extent and severity of lung lesions were related to serum levels of Hp.

Changes in haptoglobin, C-reactive protein and pig-MAP during a housing period following long distance transport in swine

The aim of this study was to investigate the effects of a housing period following long distance transport on haptoglobin (Hp), C-reactive protein (CRP) and pig major acute phase protein (pig-MAP) in swine. After transportation, 80 gilts were allotted to group A, B, C, or D. Blood samples were collected on arrival and 28 days later; additional samples were collected from Group C on day 14, and from Group D on days 3, 5 and 14. Acute phase proteins (APPs) in Group A were significantly lower on day 28 than on day 1; the opposite occurred in Group B because of a tail biting episode. In Group C, values remained elevated on day 14 and showed a reduction on day 28; in Group D elevated levels detected on day 14 were preceded by a decrease from days 1 to 5. The results indicate that stressors associated with transportation and new accommodation can cause an increase in APPs that could be useful indicators of welfare during transport and routine management.

Pig-MAP and haptoglobin concentration reference values in swine from commercial farms

Pig-MAP (Major Acute-phase Protein) and haptoglobin concentrations were determined in pigs from commercial farms, and reference intervals obtained for different productive stages. Pig-MAP serum concentrations were lower in sows than in adult boars (mean values 0.81 vs. 1.23 mg/mL) and the opposite was observed for haptoglobin (1.47 vs. 0.94 mg/mL). No differences were found between parities, except for a minor decrease in haptoglobin concentration in the 4th parity. A linear correlation between pig-MAP and haptoglobin concentration was observed. In the period 4-12 weeks of life, pig-MAP mean concentrations were around 1mg/mL, being lower in the finishing period (0.7-0.8 mg/mL). Haptoglobin concentrations increased with time, from around 0.6 mg/mL at 4 weeks of age to 1.4 mg/mL at 12 weeks. Mean values of around 0.9 mg/mL were observed in the finishing period. A wider distribution of values was observed for haptoglobin than for pig-MAP concentrations. Differences between herds were observed, with the highest values obtained in a herd with signs of respiratory disease.

Serum concentrations of C-reactive protein, serum amyloid A, and haptoglobin in pigs inoculated with African swine fever or classical swine fever viruses

OBJECTIVE

To determine serum concentrations of the selected acute-phase proteins (APPs) haptoglobin, serum amyloid A (SAA), and C-reactive protein (CRP) in pigs experimentally inoculated with classical swine fever (CSF) and African swine fever (ASF) viruses.

ANIMALS

8 crossbred (Large White x Landrace) 10-week-old pigs.

PROCEDURES

Pigs were allocated to 2 groups (4 pigs/group). One group was inoculated with the CSF virus Alfort 187 strain, whereas the other groupwas inoculated with the ASF virus Spain 70 isolate. Blood samples were collected at various time points. At the end of the study, pigs were euthanized and a complete necropsy was performed, including histologic and immunohistochemical analyses.

RESULTS

Serum concentrations of APPs increased in pigs inoculated with CSF and ASF viruses, which suggested an acute-phase response in the course of both diseases. The most noticeable increase in concentration was recorded for SAA in both groups (up to a 300-fold increase for CSF virus and an approx 40-fold increase for ASF virus), followed by CRP and then haptoglobin, which each had only 3- to 4-fold increases.

CONCLUSIONS AND CLINICAL RELEVANCE

Serum concentrations of APPs increased significantly in pigs inoculated with CSF and ASF viruses. However, differences were evident in serum concentrations of the proteins evaluated in this study.

Evaluation of the acute phase protein haptoglobin as an indicator of herd health in slaughter pigs

Health is an important aspect of animal welfare, which is difficult to assess at herd level. Clinical examination of individual animals is time-consuming, and most measures of clinical herd health depend significantly on the examiner. Acute phase proteins are produced during inflammatory processes, and could therefore be used as general markers of infection and injury. Our objective was to evaluate whether haptoglobin could be used to monitor the health status of herds at slaughter.

107 groups of 20 slaughter pigs each were examined at two large abattoirs. Clinical signs of tail biting, lameness, injuries, abscesses, pneumonia, pleurisy, hepatitis and gastritis were recorded. The association between elevated haptoglobin concentration in meat juice samples and clinical signs was assessed via multiple logistic regression.

Pigs from groups in which tail biting, lameness, othaematomas, abscesses, pneumonia, pleurisy, pericarditis or condemnations of livers, lungs or carcasses occurred, showed higher levels of haptoglobin than pigs from slaughter groups without any of these clinical signs. In the multiple regression model, only the variables of lameness and tail biting were statistically significant. The haptoglobin test classified 66% of all slaughter groups correctly according to the presence of these clinical signs. These results demonstrate the potential for haptoglobin to be used as a screening test to identify problem herds at slaughter.

Porcine Acute Phase Protein Concentrations in Different Diseases in Field Conditions

Five acute phase proteins (APPs) [C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin (Hp), pig-MAP and albumin] were measured in pigs with naturally occurring infections by porcine reproductive and respiratory syndrome virus (PRRSV), Aujeszky's disease virus (ADV), porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae, and in animals with tail and ear bites, arthritis and other acute inflammatory processes. Healthy specific pathogen-free (SPF) pigs were used as controls. In PRRSV-infected pigs, all APPs with the exception of pig-MAP exhibited significant changes compared with controls. In animals affected with ADV only Hp presented changes of statistical significance, whereas pigs with PCV2 showed marked modifications in all APPs tested. Animals affected with Mycoplasmosis showed concentrations of all positive APPs significantly above levels obtained in SPF pigs, though albumin concentrations did not differ from controls. Finally, all APPs studied showed substantial changes in pigs with acute inflammation. The results indicated that an acute phase response was developed in the different diseases studied, this response being higher in animals with clinical signs and concurrent bacterial processes. Haptoglobin would be the APP that better reflects pathological states; however, to get more complete and valuable information it might be advisable to perform APPs profiles including another APP, such as CRP or SAA.

The porcine acute phase protein response to acute clinical and subclinical experimental infection with Streptococcus suis

The pig acute phase protein (APP) response to experimental Streptococcus suis (S. suis) infection was mapped by the measurement of the positive APPs C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin (Hp) and major acute phase protein (pig-MAP) and the negative APPs albumin and apolipoprotein (Apo) A-I. The aim was to elucidate the differences in the acute phase behaviour of the individual APPs during a typical bacterial septicaemic infection. Pigs were inoculated subcutaneously with live S. suis serotype 2 and blood was sampled before and on various days post inoculation (p.i.), until the pigs were killed and autopsied on day 14 p.i. Clinical signs (fever and lameness) were observed in four of the five inoculated pigs from day 2 p.i., and these pigs also had arthritic lesions at autopsy. CRP and SAA showed fast increases in serum concentrations, CRP being elevated from days 1 to 12 p.i. and peaking at 10 times the day 0-levels on day 1 p.i. SAA rose quickly to peak levels of 30-40 times the day 0-level on days 1-2 and returned to pre-inoculation level on day 5 p.i. Hp and pig-MAP showed slightly slower responses, both peaking around 5 days p.i. Hp was increased throughout the experiment with maximum levels around 10 times the day 0-levels, and pig-MAP was elevated on days 1-12 p.i. with peak levels of around seven times the day 0-levels. Apo A-I was decreased from days 1 to 8 and showed minimum levels of about 40% of day 0-levels around 1-2 days p.i. No clear pattern of changes in albumin levels could be identified. One pig, showing clinical signs on day 2 only, also showed an APP response, although of a relatively short duration, whereas three pigs presenting clinical signs for several days had a more protracted acute phase response. Remarkably, the one pig showing no clinical signs and no arthritic lesions showed an APP response comparable to that of the other, clinically affected pigs. Thus, both acute clinical and subclinical S. suis infection could be revealed by the measurement of one or more of the APPs CRP, SAA, Hp, pig-MAP and Apo A-I. The combined measurement of two or three APPs, including proteins with slow and fast kinetics, should be used to achieve the highest sensitivity for the detection of ongoing S. suis infection during a prolonged time period. A diagnostic tool based on such APP-measurements could considerably improve strategic control procedures for this important infection.

Importance of sanitary environment for growth performance and plasma nutrient homeostasis during the post-weaning period in piglets

Deterioration of sanitary conditions in piggeries is known to limit growth performance through inducing a moderate immune response. This article reports the results of an experiment performed to reproduce the consequences of bad sanitary conditions on growth performance and nutrient plasma concentrations of piglets after weaning. We propose to use these experimental conditions as a model for studying the interactions between nutrition and pig health. In this experiment, 20 pairs of littermate piglets were selected and weaned at 28 days of age on the basis of their body weight. Within each pair, piglets were pair-fed and each one was affected to one of the two experimental groups. The first group was housed in a clean environment and was fed an antibiotic supplemented standard diet. The second group was kept in unsanitary rooms, mixed with non-experimental piglets and was fed the same standard diet but without antibiotic supplementation. Compared to pigs kept in the clean environment, piglets kept in the unsanitary environment had significantly lower rate of weight gain and feed efficiency from weaning to 20 d post weaning then from 36 - 45 d post weaning. They also displayed higher plasma concentrations of haptoglobin, copper, vitamin B12 and lysine but lower concentrations of glutathione, pyridoxal-5-phosphate, folic acid, threonine and tryptophan. Our results showed that a reduction of growth performance and a modification of nutrient utilization can be induced by decreasing the sanitary quality of environment where pigs are kept after weaning and after transition to another building. This response could be explained by a moderated activation of body defences.

The concentration of apolipoprotein A-I decreases during experimentally induced acute-phase processes in pigs

In this work, apolipoprotein A-I (ApoA-I) was purified from pig sera. The responses of this protein after sterile inflammation and in animals infected with Actinobacillus pleuropneumoniae or Streptococcus suis were investigated. Decreases in the concentrations of ApoA-I, two to five times lower than the initial values, were observed at 2 to 4 days. It is concluded that ApoA-I is a negative acute-phase protein in pigs.

Lameness in Piglets. Abrasions in Nursing Piglets and Transfer of Protection towards Infections with Streptococci from Sow to Offspring

A group of 175 newborn piglets were monitored with respect to development of abrasions and lameness. Lameness was diagnosed in 10.9% of the piglets. About every second litter was affected and around 75% of these diagnoses took place during the first 3 weeks of life. Skin lesions were present already on day 3. They increased in magnitude until day 10 and thereafter declined. They were generally bilateral and most commonly observed as abrasions over the carpal joints. Hocks, face and tails were affected in a similar way, but at lower magnitudes. Sole bruising was observed in 87% of the piglets on the third day of life, and moderate to severe lesions dominated until day 10. Thereafter the incidence decreased, indicating healing with time. Still 39% of the piglets were affected at day 17. There was a significant positive correlation between skin lesions of carpus and hock within all examination days in selected piglets with known identity (n = 48). Between day 10 and 17 significant positive correlations were found within all examination sites with exception of abdomen and teats. The offspring of sows treated against mastitis expressed more abrasions then piglets delivered by healthy sows and the mortality during the first 17 days postpartum was significantly higher among piglets delivered by sows treated for mastitis. The level of serum antibodies to Streptococcus equisimilis in eight dams decreased during the last month of gestation and a declining maternal immunity to S. equisimilis was demonstrated in all piglets (n = 47) during the first 5 weeks of life. During the first 2 weeks of life somewhat lower median levels of serum antibodies were recorded among the piglets that were treated against arthritis (n = 8).