Serum acute phase response induced by different vaccination protocols against circovirus type 2 and Mycoplasma hyopneumoniae in piglets

Multiplex Assay to Determine Acute Phase Proteins in Modified Live PRRSV Vaccinated Pigs

Acute phase protein (APP) response to vaccine challenges is an attractive alternative to natural infection for identifying pigs with increased disease resilience and monitoring the productive performance. Currently, the methods used for APP quantification are diverse and often based on techniques that use antibodies that are not necessarily pig specific. The objective of this work is the development of a method based on a UPLC-SRM/MS system for simultaneous determination of haptoglobin, apolipoprotein A1, C-reactive protein, pig-major acute protein, and serum amyloid A and its application in pigs to monitor the effect of a vaccine administered against porcine reproductive and respiratory syndrome virus (PRRSV). With the aim of tracing the complete analytical process for each proteotypic peptide, a synthetic QconCat polypeptide construct was designed. It was possible to develop an SRM method including haptoglobin, apolipoprotein A1, pig-MAP, and serum amyloid A1. The PRRSV vaccine only affected haptoglobin. The pigs with positive viremia tended to show higher values than negative pigs, reaching significant differences in the three haptoglobin SRM-detected peptides but not with the data acquired by immunoenzymatic and spectrophotometric assays. These results open the door to the use of SRM to accurately monitor APP changes in experimental pigs.

New insights into swine dysentery: faecal shedding, macro and microscopic lesions and biomarkers in early and acute stages of Brachyspira hyodysenteriae infection

BACKGROUND

Swine dysentery (SD) is a severe mucohaemorrhagic colitis in pigs caused classically by Brachyspira hyodysenteriae. Although several aspects of B. hyodysenteriae infection dynamic are already described, further research in the early stage of this infection is required. In this study, 7-week-old pigs were orally challenged with B. hyodysenteriae to obtain information about faecal shedding, macro and microscopic intestinal lesions and serum acute phase proteins in pigs at the onset of B. hyodysenteriae shedding (early infection group, n = 8), in pigs with mucohaemorrhagic diarrhoea (acute infection group, n = 8) and in non-infected controls (n = 16).

RESULTS

First B. hyodysenteriae detection by q-PCR and first loose stools with blood and mucus occurred both at 8 days post-inoculation. The lapse between a positive q-PCR and observation of mucohaemorrhagic diarrhoea ranged from 0 to 3 days, except in a single pig in which this period lasted 5 days. Macroscopic lesions were observed in the large intestine from both infected groups although more frequent and severe in acute infection group. Microscopic observation of the apex mucosa revealed that in early infection only higher ulceration values were observed compared to healthy controls. In contrast, the acute infection group exhibited higher ulceration, neutrophils infiltration and increased mucosal thickness compared to the other two groups. Among the serum biomarkers tested, only haptoglobin, C-reactive protein, and creatine kinase showed a significant increase in pigs in the acute infection period compared to controls, whereas haptoglobin was the only factor with a significant increase at the early infection compared to non-infected animals.

CONCLUSIONS

This study provides new insights about SD and remarks the complex and limited options to perform an early detection of infected animals beyond PCR diagnosis.

Effects of improved early-life conditions on health, welfare, and performance of pigs raised on a conventional farm

Nowadays, most pigs are raised indoors, on intensive farms providing a poor environment. In these conditions, the risk of the occurrence of damaging behaviours is high, with dramatic consequences for animal health and welfare as well as economic losses for farmers. Early-life conditions may predispose individuals to develop damaging behaviours later in life. In contrast, reinforcing affiliative behaviours between piglets before weaning might help to prevent tail-biting episodes. In this field study, we aimed at improving early-life conditions of piglets on a commercial farm by completely suppressing painful procedures and staggering their exposure to weaning stress factors. The alternative early-life management strategy combined housing in free-farrowing pens with temporary crating of the sow, socialisation during the lactation period with whole-life maintenance of the hierarchical groups, and delayed transfer to the postweaning room after sow removal. Control conditions included birth in farrowing crates, tail docking, absence of socialisation during the lactation period, abrupt weaning with immediate transfer to the postweaning room and mixing with non-littermates. We evaluated the health, welfare, and performance of alternatively raised pigs (n = 80) as compared to controls (n = 75). Visits were made throughout the lifespan of individuals to evaluate their growth and health status. Body and tail lesions were scored as proxy measures of aggressiveness and impaired welfare. Blood and bristle samples were periodically collected to evaluate stress, inflammation and immune competence. While the whole-life performance of pigs was similar among groups, the alternative early-life conditions prevented the growth slowdown usually observed after weaning. In addition, alternatively raised pigs displayed more neutrophils, eosinophils and monocytes the day after weaning, as well as higher C-Reactive Protein levels. One week later, their monocytes displayed greater phagocytic capacity. Altogether, these data suggest an enhanced innate immune competence for alternatively raised pigs around weaning. Piglets reared under alternative conditions also exhibited fewer and less severe body lesions than standard pigs, one week after weaning. In contrast, they showed more tail lesions on days 36 and 66 associated with greater levels of acute phase proteins (C-Reactive Protein and haptoglobin). To conclude, alternative early-life management better prepared piglets for weaning. However, the whole-life maintenance of early-established social groups was not sufficient to prevent the occurrence of damaging behaviours in undocked pigs.

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.

Clostridioides difficile-mesocolonic oedema in neonatal suckling piglets develops regardless of the fibre composition in sow's diets

Maternal dietary factors have been reported to influence Clostridioides difficile colonisation in the offspring. Twenty suckling piglets from sows fed diets supplemented with high-fermentable sugar beet pulp (SBP) or low-fermentable lignocellulose (LNC) fibres during gestation and lactation were dissected in the first week after birth. Postmortem analysis included clinical mesocolon and faecal scoring, concentration of C. difficile and respective toxins in colon digesta and faeces, immunoglobulins in serum and inflammatory markers in serum and colon tissues. Sow colostrum was assessed for nutrients, immunoglobulins and biogenic amines. Toxin-neutralising IgG antibodies were measured in colostrum and serum of the sows, and in colon digesta and serum of the piglets. Mesocolonic oedema of different severity was present in most of the piglets from both sows' feeding groups. Concentrations of C. difficile, toxins and calprotectin in colon digesta and faecal contents did not differ between the study piglets. Calprotectin correlated positively with mesocolon score (rho = 413, P = 0.07). Piglets from sows fed LNC vs SBP tended to have higher IgA (P = 0.089), IgG (P = 0.053), total Ig (P = 0.053), albumin (P = 0.075) and total protein content (P = 0.007) in serum. Colon tissues of piglets from the SFB vs LNC had upregulated expression of ZO-1 (P = 0.021), PCNA (P = 0.015) and TGF-β (P = 0.014). Titers of anti-toxin-IgG-antibodies in serum and colostrum and in piglet colon digesta and serum did not differ between sows from both dietary groups, but they all showed strong positive correlations. In conclusion, dietary sugar beet pulp or lignocellulose fed to sows did not influence the concentrations of C. difficile and toxins titers in colon digesta and faeces of neonatal piglets.

Safety and Efficacy of the Bordetella bronchiseptica Vaccine Combined with a Vegetable Oil Adjuvant and Multi-Omics Analysis of Its Potential Role in the Protective Response of Rabbits

Infectious respiratory diseases caused by Bordetella bronchiseptica (Bb) are seriously endangering the development of the rabbit industry in China. Unfortunately, no licensed vaccines are available for this pathogen. The present study was designed to determine whether the inactivated Bb antigen formulated with vegetable oil adjuvant (named E515) which contains soybean oil, vitamin E, and ginseng saponins, functions as a safe and effective vaccine (E515-Bb) against Bb infection in rabbits. Based on local and systemic reactions, both the E515 adjuvant alone and the E515-Bb vaccine exhibited good safety in rabbits. Immune response analysis implies that rabbits immunized with the E515-Bb vaccine produced significantly higher, earlier, and longer-lasting specific antibody responses and activated Th1/Th2/Th17 cell responses than those immunized with the aluminum hydroxide (Alum)-adjuvanted Bb vaccine (Alum-Bb) or Bb antigen alone. Moreover, the E515-Bb vaccine effectively protected rabbits from Bb infection. Additionally, integrated multi-omics analysis revealed that the immunoprotective effect of the E515-Bb vaccine was achieved through upregulation of the complement and coagulation cascades and cell adhesion molecule (CAM) pathways, and the downregulation of the P53 pathway. Overall, these results indicate that the E515-Bb vaccine is safe, elicits an efficient immune response and provides good protection against Bb infection in rabbits. Thus, the E515-adjuvanted Bb vaccine can be considered a promising candidate vaccine for preventing Bb infection.

One Dose of a Novel Vaccine Containing Two Genotypes of Porcine Circovirus (PCV2a and PCV2b) and Mycoplasma hyopneumoniae Conferred a Duration of Immunity of 23 Weeks

Porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae (Mhyo) are important swine pathogens for which vaccination is a key control strategy. Three separate studies were performed to evaluate the duration of immunity (DOI) conferred by a novel vaccine combining PCV2a/PCV2b and Mhyo into a ready-to-use formulation. In each study, three-week-old naïve piglets were vaccinated (Day 0) and challenged 23-weeks later (Day 159) with either PCV2a, PCV2b or Mhyo. Pigs were euthanized three-to-four-weeks post-challenge. Vaccinated pigs had significantly lower PCV2 viremia from Day 168 until Day 175 (PCV2a study) or until euthanasia (PCV2b study), respectively. Fecal shedding was significantly lower for PCV2a-challenged from Day 171 until Day 178, and for PCV2b-challenged from Day 172 until euthanasia. In the PCV2a challenge study, there were no differences among vaccinates and controls in terms of percent of pigs positive for PCV2 immunohistochemistry, histiocytic replacement, or lymphoid depletion. However, significant differences for immunohistochemistry and histiocytic replacement, not lymphoid depletion, were observed among vaccinates and controls following PCV2b challenge. Vaccination supposed a significant reduction in the mean percentage of Mhyo-like lesions in the lung. Percentages of lung tissues positive for Mhyo via immunohistochemistry were 49.3% and 67.1% for vaccinated and control groups, respectively. One dose of the novel PCV2a/PCV2b/Mhyo vaccine conferred robust protection against challenge 23-weeks later for all three fractions.

Evidence of haptoglobin in the porcine female genital tract during oestrous cycle and its effect on in vitro embryo production

Recent evidence supports involvement of the acute phase protein haptoglobin in numerous events during mammalian reproduction. The present study represents an in-depth investigation of haptoglobin expression and secretion in the porcine oviduct and uterus, and assesses its effect on porcine in vitro embryo production. A systematic study was made of sows in different oestrous stages: late follicular, early luteal and late luteal stages. Relative haptoglobin mRNA abundance was quantified by RT-qPCR. In addition, expression of the protein was analysed by immunohistochemistry and the results were complemented by Western-blot and proteomic analyses of the oviductal and uterine fluids. In vitro porcine fertilization and embryo culture were carried out in the presence of haptoglobin. The results indicate that haptoglobin mRNA expression in the porcine oviduct and uterus is most abundant during the late luteal stage of the oestrous cycle. By means of Western blot and proteomic analyses haptoglobin presence was demonstrated in the oviduct epithelium and in the oviductal and uterine fluids in different stages of the oestrous cycle. The addition of haptoglobin during gamete co-incubation had no effect on sperm penetration, monospermy or efficiency rates; however, compared with the control group, blastocyst development was significantly improved when haptoglobin was present (haptoglobin: 64.50% vs. control: 37.83%; p < 0.05). In conclusion, the presence of haptoglobin in the oviduct and uterus of sows at different stages of the oestrous cycle suggests that it plays an important role in the reproduction process. The addition of haptoglobin during in vitro embryo production improved the blastocyst rates.

Effects of Dietary Supplementation of Garlic and Oregano Essential Oil on Biomarkers of Oxidative Status, Stress and Inflammation in Postweaning Piglets

The effects of two different concentrations of micro capsuled oregano essential oil (OEO) and purple garlic powder on biomarkers of oxidative status, stress, and inflammation, as well as on average daily gain (ADG) and feed conversion ratio (FCR), were evaluated in piglets during the postweaning period. The trial was carried out with 300 crossbred pigs of 21 days of age fed with different concentrations of OEO and purple garlic powder and ZnO. Saliva and serum samples were taken to evaluate a panel of biomarkers of oxidative status, stress, and inflammation. OEO and garlic powder at 0.4% did not produce significant changes in C-reactive protein (CRP) and cortisol and yielded higher levels of the antioxidant biomarker CUPRAC in serum than higher doses (p < 0.01); they yielded a better ADG than the control and ZnO diets. OEO and garlic powder at higher concentrations than 0.4% showed higher concentrations of CRP (p < 0.05). Overall, doses of OEO and garlic powder at 0.4% did not lead to inflammation, stress, or negative changes in oxidative biomarkers in piglets during the postweaning period and gave better productive performance than the control and ZnO diets. High doses of OEO and garlic powder were ineffective and could negatively affect the animals. Therefore, our results highlight the importance of the dose used when OEO or garlic are supplemented to piglets.

Welfare Benefits of Intradermal Vaccination of Piglets

Vaccination is reported as a stressful and painful event for animals. This study investigated whether needle-free intradermal vaccination improves the welfare of weaned pigs through the reduction of stress and pain biomarkers and improvement of behavioural parameters compared to traditional intramuscular injection with a needle. A total of 339 weaned piglets were allocated to 3 treatment groups: Intradermal Application of Liquids (IDAL) pigs, vaccinated against Porcine Circovirus type 2 (PCV2) by means of intradermal vaccination using a needle-free device Porcilis^® PCV ID; Intramuscular (IM) pigs vaccinated against PCV2 with Porcilis^® PCV intramuscularly with a needle; CONTROL pigs were managed identically but did not receive any vaccine injection. At the time of the injection, the reaction of IDAL piglets was similar to control piglets, whereas a greater percentage of piglets vaccinated intramuscularly displayed high-pitch vocalizations (7% CONTROL, 7% IDAL, 32% IM) and retreat attempts (3% CONTROL, 7% IDAL, 39% IM). The day after vaccination, IDAL piglets did not differ from the control piglets for any of the behavioural variables studied through scan samplings. IM piglets showed a lower frequency of social negative interactions (p = 0.001) and rope manipulation (p = 0.04) compared to the CONTROL group. Resting postures did not differ between treatments. At 28 h post-vaccination, IDAL piglets presented lower blood C-reactive protein levels (CONTROL = 20 μg/mL; IDAL = 39 μg/mL; IM = 83 μg/mL, p < 0.0001) and blood Haptoglobin (CONTROL = 1.8 mg/mL; IDAL = 1.9 mg/mL vs. IM = 3.1 mg/mL, p < 0.0001) compared to IM piglets. Salivary chromogranin A and alpha-amylase did not differ between treatment groups when measured 25 min post-vaccination. The method of vaccination did not affect the growth of the piglets or their rectal temperature. These results support that needle-free intradermal vaccination reduces vaccination-related pain in growing pigs.

Comparison of Mycoplasma hyopneumoniae and porcine circovirus 2 commercial vaccines efficacy when applied separate or combined under experimental conditions

Background

Mycoplasma hyopneumoniae (Mhyo) and Porcine circovirus 2 (PCV-2) are two of the most significant infectious agents causing economic losses in the weaning to slaughter period. Due to their similar vaccination age, the objective of this study was to assess the efficacy of two already existing Mhyo (Hyogen®) and PCV-2 (Circovac®) vaccines when administered separately or combined (RTM) by means of Mhyo or PCV-2 experimental challenges.

Results

Seven groups of animals were included in the study, being three of them challenged with PCV-2, three with Mhyo and one composed of non-challenged, non-vaccinated pigs. Within each experimental challenge, non-vaccinated (NV) groups were compared with double vaccinated groups using the commercial products separated (VS) or combined (VC). Both vaccinated groups showed significant differences for most parameters measured regarding PCV-2 (serology, percentage of infected animals and viral load in tissues) and Mhyo (serology and gross lesions) when compared to NV groups. VS and VC offered similar results, being only significantly different the PCV-2 antibody values at different time points (higher in the VS group) of the study, although not at the termination day (21 days post-PCV-2 inoculation).

Conclusion

The present study expands the knowledge on the possibility of using two separate Mhyo and PCV-2 commercial vaccines as a RTM product, which offered equivalent virological, immunological and pathological outcomes as compared to these vaccines when used by separate.

Effects of vaccination on acute-phase protein response in broiler chicken

Broiler chickens experience an acute-phase response (APR) through vaccination, which reflects the innate immunity and stress related to immunization. It is also considered that APR can modulate adaptive immunity and response to infection. As biomarkers for APR, assessing the acute-phase proteins (APPs) function and their levels in response to immunization is of great value for vaccine design, development and administration. In this study, the heterophils/lymphocyte (H/L) ratio and the level of APPs was evaluated in broilers with three different Newcastle disease (ND) vaccination regimens. Inactivated ND vaccine (IND) was administered by the intramuscular route. Live attenuated strains, Lasota and Vitapest, was administered by ocular routes. H/L ratio, serum amyloid A (SAA) and alpha-1 acid glycoprotein (AGP) were measured before and after two rounds of vaccination on days 10 and 21. In a comparison between the three vaccines, H/L ratio in IND group significantly increased to 3 fold (1.48 ± 0.41) after the first vaccination while the Lasota and Vitapest showed a milder response. The concentration of SAA increased after 24h by 1.8-fold in IND group (0.116 ± 0.015 mg/L) and 2-fold in Lasota group (0.14 ± 0.002 mg/L). Significant changes were found in Vitapest group after 48h post vaccination (0.113 ± 0.016 mg/L). Elevation pattern of AGP, 24 hours after first vaccination in IND (3.5-fold) and Vitapest (2.5-fold) was different from Lasota in which the peak was reached after 48 hours (2.9-fold). Except for IND group, no significant changes in SAA and AGP concentrations were detected after the second vaccination. A significant positive correlation between SAA values at day 22 and HI titers at day 28 (r = 0.998, P≤0. 0.005) was found. According to these results, different types of ND vaccines can cause different patterns of acute phase responses. Assessment of stress and level of acute-phase proteins can be used for prediction of immune response outcomes in vaccine design and development.

Porcine Breed, Sex, and Production Stage Influence the Levels of Health Status Biomarkers in Saliva Samples

In this study, the influence of several factors such as breed, sex, and production stage over the normal range values of salivary biomarkers of health status was evaluated in pigs. A total of 409 pigs of 2 different breeds (conventional Large White × Duroc and Iberian pigs) were included in the study. Animals were divided into different groups according to their sex (male or female) and the stage of the production cycle they were in (post-weaning, nursery, fattening, and finishing). The levels of an inflammatory marker, adenosine deaminase (ADA), and two acute phase proteins, C-reactive protein (CRP) and haptoglobin (Hp) were measured in saliva samples. Moreover, the total antioxidant capacity level (TAC) was quantified for the first time in porcine saliva; therefore, an analytical validation and stability analysis during storage at −80°C were also performed. Differences according to breed were observed for all the markers studied; thus, the influence of age and sex on the normal range values were studied separately for conventional and Iberian pigs. In Large White × Duroc pigs the overall median values of ADA, CRP, Hp and TAC were 282 U/L, 10.49 ng/mL, 0.88 μg/mL, and 21.73 μM Trolox equivalents, respectively. However, higher values of inflammatory marker and acute phase proteins were observed in males at the initial stages of the production cycle, while females presented higher values when they had reached sexual maturity. In Iberian pigs the overall median values observed were 585 U/L, 4.81 ng/mL, 0.63 μg/mL, and 21.21 μM Trolox equivalents for ADA, CRP, Hp, and TAC respectively with slight differences in the influence of the studied factors. Sex differences were not observed in the levels of acute phase proteins in Iberian pigs, probably due to the castration of males during the first days of life; however, ADA levels were found to be higher in male pigs at the end of the production cycle. It could be concluded that breed, sex, and production stage influence the range values of salivary markers of health status in pigs and should be taken into account to further establish reference intervals.

Inflammatory markers before and after farrowing in healthy sows and in sows affected with postpartum dysgalactia syndrome

Background

The pathogenesis of postpartum dysgalactia syndrome (PDS) in sows is not fully elucidated and affected sows often present vague clinical signs. Accurate and timely diagnosis is difficult, and PDS is often recognized with a delay once piglets begin to starve. Increased rectal temperature of the sow is an important diagnostic parameter, but it may also be influenced by a number of other parameters and is thus difficult to interpret. Inflammatory markers may be important adjuncts to the clinical assessment of sows with PDS, but such markers have only been studied to a limited extent. The objective was to characterize the inflammatory response in healthy sows and in sows suffering from PDS, and to identify biomarkers that may assist in early identification of PDS-affected sows.

Results

Thirty-eight PDS-affected (PDS+) and 38 healthy (PDS-) sows underwent clinical examination and blood sampling every 24 h, from 60 h before the first piglet was born to 36 h after parturition. In both groups, inflammatory markers changed in relation to parturition. Most inflammatory markers changed 12-36 h after parturition [white blood cell counts (WBC), neutrophil counts, lymphocyte counts, tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), serum amyloid A (SAA), C-reactive protein (CRP), haptoglobin (Hp), iron (Fe) and albumin (ALB)]. Changes in neutrophil counts, lymphocyte counts, CRP, Fe and ALB were observed -12 to 0 h before parturition. WBC, neutrophil and lymphocyte counts, serum concentrations of TNF-α, IL-6, Hp and Fe differed between PDS+ and PDS- sows. These differences were mainly apparent 12 to 36 h after parturition, but already at 12 h before parturition, PDS+ sows had lower lymphocyte counts than PDS- sows.

Conclusions

Parturition itself caused significant inflammatory changes, but PDS+ sows showed a more severe response than PDS- sows. WBC, neutrophil and lymphocyte counts, and concentrations of TNF-α, IL-6, Hp and Fe can be potential biomarkers for PDS. Lymphocyte counts may be used to detect PDS at pre-partum. To assess their diagnostic potential, these markers must be investigated further and most likely combined with assessment of clinical parameters and other biomarkers for improved identification of sows at risk of developing PDS.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1382-7) contains supplementary material, which is available to authorized users.