Salivary alpha-amylase activity and cortisol in horses with acute abdominal disease: a pilot study

Association between Eosinophil Count and Cortisol Concentrations in Equids Admitted in the Emergency Unit with Abdominal Pain

Stress leukogram includes eosinopenia as one of its main markers (neutrophilia, eosinopenia, lymphopenia, and mild monocytosis). Cortisol is the main stress biomarker, which is also strongly correlated with the severity of gastrointestinal diseases. This study aimed to determine the relationship between salivary cortisol and the eosinophil cell count (EC) in equids with abdominal pain. To do this, 39 horses with abdominal pain referred to an emergency service were included. All samples were taken on admission, and several parameters and clinical data were included. Equids were classified according to the outcome as survivors and non-survivors. Non-surviving equids presented higher salivary cortisol concentrations (Non-Survivors: 1.580 ± 0.816 µg/dL; Survivors 0.988 ± 0.653 µg/dL; p < 0.05) and lower EC (Non-Survivors: 0.0000 × 103/µL (0.000/0.0075); Survivors: 0.0450 × 103/µL (0.010/0.1825); p < 0.01). In addition, the relationship between salivary cortisol concentration, EC, and the WBC was determined. Only a strong correlation (negative) was observed between cortisol and EC (r = -0.523, p < 0.01). Since cortisol is not an analyte that can be measured routinely in clinical settings such as emergencies, the EC could be a good alternative. While the results are promising, further studies are needed before EC can be used confidently in routine practice to predict survival in cases of abdominal pain.

Effect of wither application of an analogue of pig appeasing pheromone on encounters between unfamiliar mini-pigs

BACKGROUND

The practice of mixing unfamiliar pigs on farms is common but results in fighting, welfare problems and performance issues. Pigs have different ways of resolving social conflicts, including aggressive and affiliative behaviours. Synthetic appeasing pheromones have demonstrated many positive effects in animal husbandry and are regularly used by breeders to improve animal welfare and performance. The aim of the study was to investigate the effect of a new method of applying pig appeasing-pheromone (PAP) to the withers in an experimental model of pig mixing to determine whether PAP reduced aggression and fighting, increased prosocial behaviours, and improved behavioural and physiological indicators of welfare.

RESULTS

PAP reduced fighting between mini-pigs (df = 1; F = 13.47; P = 0.001; mixed logistic regression). Even if not significant, agonistic behaviours tended to be reduced when the treatment was applied (df = 1; F = 4.14; P = 0.058; mixed logistic regression). Likewise, mini-pigs seemed to be scored as not aggressive at all (df = 1; F = 3.61; P = 0.070; GLMM) and to be less aggressive toward the other pig than when placebo was applied. Concerning the latency of the first contact without aggression, a significant effect was found between the PAP and placebo groups (df = 1; χ² = 4.74; P = 0.0295; Cox model). Moreover, even if not significant, the treated mini-pigs seemed to spent more time looking at each other (df = 1; F = 3.59; P = 0.071; GLMM) and immobile and/or ground sniffing (df = 1; F = 3.18; P = 0.088; GLMM) than those that received placebo. No significant difference was found between groups for salivary cortisol concentration (df = 1; F = 0.10; P = 0.752; GLMM), but variances between groups were heterogeneous at every time. No significant difference was found between groups regarding alpha-amylase activity (df = 1; F = 0.25; P = 0.621; GLMM), but variances between groups were heterogeneous at T0, T1 and T3. These results indicate that the variability (dispersion) within each group was lower when PAP was applied than when the placebo was applied.

CONCLUSIONS

The new method of applying PAP improved welfare of mini-pigs (as models of domestic pigs) by reducing fighting, among other interesting results. PAP seems thus a promising biomimetic tool to enhance animal welfare in pig production systems.

Risk factors, hematological and biochemical profile associated with colic in Delman horses in Gresik, Indonesia

Background: Horses are herd animals that have been domesticated in the last century. In several countries, an overview of risk factors and clinical evaluation in horses with colic has not been well‐described. This study aimed to evaluate risk factors and hematological profiles in horses associated with colic in Gresik, East Java, Indonesia.

Methods: A cross-sectional study was performed during April - October 2019. A total of 115 horses were diagnosed based on physical examination, clinical symptoms, and rectal examination. A questionnaire was asked to the horse-owners to analyze the risk factors while the clinical examination was performed and blood samples were collected for pre-treatment and 14 days post-treatment. Hematological profile was evaluated from a whole blood sample. Serum cortisol, plasma epinephrine, and norepinephrine concentrations were also evaluated after separating the aliquots. 

Results: Of the 115 horses, 96 were diagnosed with colic. The horses with colic showed a significant association between cases with gender (p<0.021), breed (p<0.000), wheat bran feeding (p<0.015), concentrate feeding (p<0.003), anthelmintics administration (p<0.000), gastrointestinal parasites (p<0.000), dental diseases (p<0.024), previous exposure to colic (p<0.000), body condition score (p<0.000), and access to water per day (p<0.000). Based on whole blood and serum evaluation, there were ameliorated significantly on the hematological profile (p<0.01), serum cortisol (p<0.05), and plasma epinephrine (p<0.01) at 14 days post-treatment.

Conclusion: This study has identified factors associated with colic in Delman horses. The study provides crucial information to investigate cases of colic and to contribute the development of healthcare strategies during treatment and clinical evaluation.

Evaluation of a Modified Bit Device to Obtain Saliva Samples from Horses

(1) Background: Accounting for the well-being of equine partners is a responsibility of those engaged in Equine-Assisted Services (EAS). Researchers took heed of this call to action by developing an innovative way to collect data to assess the physiological indicators of stress in equine participants. The collection of saliva is considered to be a minimally invasive method of data collection and is typically performed using a cotton swab; however, in equines, the introduction of a foreign object may induce stress; (2) Methods: Researchers used a modified bit to collect pooled saliva in an effort to further reduce stress during the saliva collection process. Additionally, the collection of pooled saliva, via the bit, increases the opportunity to consider additional analyses, such as oxytocin, which is more reliable in pooled saliva than site-specific saliva captured with a swab; (3) Results: A data analysis demonstrated that ample saliva was captured using the modified bit. Observational data supported that the horses demonstrated fewer physical stress signals to the bit than to the swab. Thus, the modified bit is a feasible and valid method for equine salivary sample collection; (4) Conclusions: The results suggest that the modified bit provides a viable method to collect equine saliva and supports national calls to prioritize animal welfare analysis, specifically for horses used within EAS. Future research should enhance methodological rigor, including in the process and timing, thereby contributing to the bit's validation.

Changes in saliva biomarkers during a standardized increasing intensity field exercise test in endurance horses

Salivary biomarkers could be useful to evaluate stress, fitness level, and skeletal muscle damage associated to exercise in horses in an easy and non-painful way. Therefore, this study aims to evaluate if cortisol in saliva (sCor), salivary alpha-amylase (sAMY) and butyrylcholinesterase (sBChE) and lactate (sLA) and creatine kinase (sCK) in saliva of horses can show changes during a standardized exercise test, and if they are related to heart rate variability (HRV) parameters related to sympathetic and parasympathetic tone, fitness level or skeletal muscle damage. For this purpose, ten endurance horses were submitted to a standardized exercise test in field conditions. Saliva and blood were obtained at basal time (TB), after the seven bouts of velocity (T + 01 to T + 07), and 5, 15, 30, and 45 min later (T + 5, T + 15, T + 30, and T + 45). Five endurance horses in resting condition (control group) were also enrolled. HRV and fitness level parameters, and plasma CK as a marker of muscle damage were also evaluated. Salivaryalpha-amylase increased at T + 30 (P = 0.03), sBChE at T + 5 (P = 008), and sCK at T + 07 (P = 0.009) after the exercise test, with significant differences between the exercise and control groups' results. The sCor did not show significant changes during the exercise test in the exercise group but higher concentration compared to the control horses (P < 0.001) were observed. sCor, sAMY, sBChE, and sCK showed a positive correlation (r values between 0.47 and 0.64) with the sympathetic tone and a negative correlation (r values between -0.37 and -0.56) with the parasympathetic tone. In conclusion, sAMY, sBChE, and sCK showed significant increases in ten endurance horses after an increasing intensity velocity exercise. Values of sCor, sAMY, sBChE, and sCK were associated with HRV, which is used to evaluate stress, and therefore, they could be potentially used to assess the exercise-related stress after a physical effort.

Tandem Mass Tag (TMT) Proteomic Analysis of Saliva in Horses with Acute Abdominal Disease

Simple Summary

This study shows for the first time the variation of the salivary proteome in horses with acute abdominal disease (AAD) compared with healthy horses through a high-throughput proteomic approach. A total of 118 proteins were identified, and 17 showed significant changes between the two groups. The changes observed in proteins were closely related to an impaired primary immune defense and antimicrobial capacity in the mucosa, and one salivary protein (lactoferrin) was successfully verified. These results may increase the background and knowledge of saliva composition in horses with AAD and further understanding of the physiopathological changes occurring in the organism in this disease.

Abstract

The aim of this study was to investigate the changes in the salivary proteome in horses with acute abdominal disease (AAD) using a tandem mass tags (TMT)-based proteomic approach. The saliva samples from eight horses with AAD were compared with six healthy horses in the proteomic study. Additionally, saliva samples from eight horses with AAD and eight controls were used to validate lactoferrin (LF) in saliva. The TMT analysis quantified 118 proteins. Of these, 17 differed significantly between horses with AAD and the healthy controls, 11 being downregulated and 6 upregulated. Our results showed the downregulation of gamma-enteric smooth muscle actin (ACTA2), latherin isoform X1, and LF. These proteins could be closely related to an impaired primary immune defense and antimicrobial capacity in the mucosa. In addition, there was an upregulation of mucin 19 (MUC19) and the serine protease inhibitor Kazal-type 5 (SPINK5) associated with a protective effect during inflammation. The proteins identified in our study could have the potential to be novel biomarkers for diagnosis or monitoring the physiopathology of the disease, especially LF, which decreased in the saliva of horses with AAD and was successfully measured using a commercially available immunoassay.

Changes in Saliva Analytes Associated with Lameness in Cows: A Pilot Study

Simple Summary

Saliva may contain useful biomarkers which provide information about animal welfare using convenient and non-invasive sampling methods. In addition, the development of automated techniques of measuring analytes in saliva provides advantages from the technical point of view since they are cost-effective, reliable, and replicable. In this study, 21 salivary analytes measured by automated assays were tested as potential biomarkers of lameness, one of the most prevalent diseases in dairy cows producing significant economic losses. As a result, total esterase (TEA) showed increases in saliva in a group of 11 cows with lameness, decreasing when the lameness was solved after a specific treatment consisting of a hoof trimming and a medical treatment. In addition, TEA activity correlated with the severity of the lameness. Further studies using a larger population of cows with different causes of lameness and severity should be performed to determine the potential of TEA as a biomarker of lameness in cows.

Abstract

The possible changes in a panel of 21 salivary analytes on a population of cows with lameness before and after treating lameness by hoof trimming were analyzed. Then, the analytes that showed significant changes were studied in a larger population of cows with lameness and compared with healthy cows For this purpose, two groups of cows were made by a specialized veterinarian. One consisted of healthy cows with no external signs of diseases and no hematological or biochemical abnormalities, and showing no signs of lameness according to the numerical rating system of severity (NRS, 5-point scale); and the other composed of cows showing only lameness with a NRS of 3.1 ± 0.87 and a lesion scoring system (LSS, 4-point scale) of 3.3 ± 0.89. Both groups did not differ in parity (p = 0.140), days in milk (DIM) (p = 0.780), and body condition score (BCS) (p = 0.074). Initially, 21 biochemical analytes were determined in the saliva of six cows with lameness at the diagnosis time (T0) and twenty days after hoof trimming that successfully solved the lameness (TF). This exploratory study only showed significantly higher values in lipase (Lip) and total esterase (TEA) at T0 compared to TF (p < 0.001 and p = 0.034, respectively). When both analytes were measured in the additional five lame cows and the results of all the animals of the lame group (n = 11) were compared with the healthy group (n = 11), only TEA showed higher activities in the group of lame cows than healthy cows (p = 0.004). TEA was positively correlated with both NRS and LSS (r = 0.43, p = 0.004 and r = 0.35, p = 0.003). In conclusion, this study showed that cows with lameness in our experimental conditions had higher TEA values than healthy cows, and these values decreased after treatment. This is a pilot study, and further studies using a larger population of cows with lameness due to different causes and severity should be performed to determine the potential of TEA as a biomarker of lameness in cows.

Changes in Salivary Analytes of Horses Due to Circadian Rhythm and Season: A Pilot Study

Simple Summary

The use of salivary biomarkers is gaining interest in the veterinary field, since saliva is usually easy to obtain and its collection from animals causes less stress than blood sampling. However, our knowledge of the possible factors related to daily and seasonal variations in salivary biomarkers is still in its infancy. In our study, the possible circadian or circannual variations in a panel of salivary biomarkers in horse saliva were evaluated. The results showed that daily and/or seasonal variations can be observed in cortisol, salivary alpha-amylase, total esterase, butyrylcholinesterase, adenosine deaminase, and creatine kinase. Therefore, these factors should be considered for the interpretation of these analytes when measured in horse saliva.

Abstract

This study aims to evaluate the circadian and circannual variations in a panel of analytes in horse saliva that have been previously described as biomarkers related to stress and disease, in order to interpret them correctly when they are measured in this species. This panel of analytes integrated cortisol, salivary alpha-amylase (sAA), lipase (Lip), total esterase (TEA), butyrylcholinesterase (BChE), adenosine deaminase (ADA), γ-glutamyl transferase (gGT), creatine kinase (CK), urea, total bilirubin, total protein (TP), and phosphorus. These analytes were measured in saliva obtained from a population of five clinically healthy mares from 06:30 to 20:30, every 2 h over two consecutive days in two different photoperiod seasons, winter and spring. The temperature and relative humidity did not change between the two consecutive days sampled in each sampled season, and no thermal discomfort was observed. Changes throughout the course of the day were observed for cortisol, sAA, TEA, BChE, ADA, and CK. However, a circadian pattern was only observed for cortisol, TEA, BChE, ADA, and CK. Moreover, the values obtained for sAA, Lip, and BChE were significantly different between seasons, with different daily rhythms for cortisol, TEA, BChE, and ADA depending on the season. In conclusion, this pilot study indicates that the time of the day and the season influence salivary analytes in horses, showing a rhythmic pattern for cortisol, TEA, BChE, ADA, and CK. These factors should thus be taken into consideration for the interpretation of analytes in horse saliva.

Exercise Induced Changes in Salivary and Serum Metabolome in Trained Standardbred, Assessed by 1H-NMR

In the present study, data related to the metabolomics of saliva and serum in trained standardbred horses are provided for the first time. Metabolomic analysis allows to analyze all the metabolites within selected biofluids, providing a better understanding of biochemistry modifications related to exercise. On the basis of the current advances observed in metabolomic research on human athletes, we aimed to investigate the metabolites’ profile of serum and saliva samples collected from healthy standardbred horses and the relationship with physical exercise. Twelve trained standardbred horses were sampled for blood and saliva before (T₀) and immediately after (T₁) standardized exercise. Metabolomic analysis of both samples was performed by ¹H-NMR spectroscopy. Forty-six metabolites in serum and 62 metabolites in saliva were detected, including alcohols, amino acids, organic acids, carbohydrates and purine derivatives. Twenty-six and 14 metabolites resulted to be significantly changed between T₀ and T₁ in serum and saliva, respectively. The findings of 2-hydroxyisobutyrate and 3-hydroxybutyrate in serum and GABA in equine saliva, as well as their modifications following exercise, provide new insights about the physiology of exercise in athletic horses. Glycerol might represent a novel biomarker for fitness evaluation in sport horses.

Evaluation of Potential Pain Biomarkers in Saliva and Pain Perception After Corneal Advanced Surface Ablation Surgery

Purpose

To evaluate the evolution of a set of proposed pain biomarkers in the saliva of subjects following Advanced Surface Ablation (ASA), in order to determine their validity as objective pain measures.

Methods

A multicenter, prospective, and descriptive study was carried out to assess the variations between biomarkers and perceived pain. The Inclusion criteria were healthy subjects who underwent a bilateral, alcohol-assisted surface ablation with epithelial removal (ASA). Pain intensity before and after surgery was assessed by Visual Analog Scale (VAS) and the Numeric Pain Rating Scale (NPRS). Cortisol, sAA, sIgA, testosterone, and sTNFαRII were assayed at four-time points (V0, baseline; V1, pre-surgery; V2, 1 hr post-surgery, and V3, 72 hrs post-surgery). Comorbidities and Hospital Anxiety and Depression (HADS) questionnaires were administrated before and at 6 hrs after the surgery. All patients were treated with cold patches, topical steroids, topical cold antibiotics, and benzodiazepines after ASA surgery. A descriptive analysis of biomarkers and pain intensity evolution and the agreement between biomarkers and pain was performed.

Results

Concentration of sIgA and sTNFαRII post-surgery was significantly higher at each visit compared to baseline (p-value: 0.053, p-value: <0.001, respectively). Relations between VAS scale score and putative biomarker variations were not statistically significant except for the sIgA but only at visit 0 (p-value: 0.024). The HADS questionnaire showed anxiety scores between 0 and 7 in all patients before and at 6 hrs after surgery.

Conclusion

In this study, sIgA and sTNFαRII are the two potential biomarkers that present correlation with the VAS and these salivary substances showed acceptable levels of reproducibility in healthy subjects.

Effect of food contamination and collection material in the measurement of biomarkers in saliva of horses

This study aims to evaluate the effect of the presence of food and the material used in a panel of biomarkers in saliva of horses. For the food effect study, clean saliva was incubated with a known amount of food consisting of oats, hay or grass. Significant changes were observed when saliva was incubated with oats for total protein (P = .050) and phosphorus (P = .008), with grass for total protein (P = .037), salivary alpha-amylase (sAA, P = .018), total esterase (TEA, P = .018), butyrilcholinesterase (BChE, P = .037), adenosine deaminase (ADA, P = .037), and total bilirubin (P = .018), and with hay for sAA (P = .018), phosphorus (P = .037), γ-glutamyl transferase (gGT, P = .004), and creatine kinase (CK, P = .016). For the material-based collection study, saliva using a sponge and a cotton role at the same time were collected and compared. Lower values were obtained in clean saliva collected with cotton role compared to sponge for sAA (P = .030), TEA (P = .034), BChE (P = .003), gGT (P = .002) and cortisol (P < .001) In conclusion, the presence of food and the material used for its collection, can influence the results obtained when analytes are measured in saliva of horses.

Changes in Saliva Analytes Correlate with Horses' Behavioural Reactions to An Acute Stressor: A Pilot Study

Simple Summary

Emotionality is an individual characteristic defined as the propensity to respond to stress-inducing stimuli such as fear-inducing objects or social separation. Evaluation of emotionality in horses is important as it may impact their learning performance. Although emotionality is usually assessed by measuring behavioural patterns, biomarkers could provide additional information about stress response, especially with respect to its temporal dynamics. In this study, behavioural responses were measured as well as a panel of salivary biomarkers related to stress, including salivary alpha-amylase, lipase, total esterase, butyrylcholinesterase, adenosine deaminase, and cortisol, in riding horses after acute experimental stress (the sudden opening of an umbrella). We found significant changes in most of the salivary biomarkers evaluated after the induced stress, where increases in butyrylcholinesterase were more closely related to behavioural responses to acute stress and low salivary alpha-amylase values were more closely related to quietness behaviours. Therefore, this preliminary research provides information about the relationship between behaviour patterns and biomarkers of stress in saliva in horses, and opens the possibility of wider use of selected biomarkers in saliva, such as butyrylcholinesterase or alpha-amylase, for the evaluation of acute stress in horses.

Abstract

Acute stress induces an array of behavioural reactions in horses that vary between individuals. Attempts to relate behavioural patterns and physiological responses have not always given clear-cut results. Here, we measured the changes in a panel of salivary components: salivary alpha-amylase (sAA), lipase, total esterase (TEA), butyrylcholinesterase (BChE), adenosine deaminase (ADA), and cortisol, and their potential link with horses’ behaviours after acute stress. Saliva samples were collected in nine riding horses subjected to a test consisting of opening an umbrella. Saliva sampling was obtained at a basal time point in the stall (T1), in the test indoor arena (T2), at a time of stress (T3), and 30 min (T4) and 60 min (T5) later. The horses’ behaviour was recorded at T3 for 1 min. sAA, lipase, TEA, and BChE showed significant changes along time, increasing at T3 for BChE, and decreasing at T4 for sAA and BChE. Butyrylcholinesterase appeared to be the most reliable predictor of behavioural responses, as it correlated with the index of emotionality, of laterality, and the occurrence of alarm signals, while sAA decreased when horses expressed quieter behaviours. These first results bring promising lines for novel, more precise physiological markers of acute stress in horses that can bridge the gap between behaviour and physiology.

Changes in saliva analytes in equine acute abdominal disease: a sialochemistry approach

BACKGROUND

The biochemical components of saliva can change in certain pathologies in horses, for example in acute abdominal disease. The aim of this study was (1) to evaluate if a panel of biochemical analytes usually used in serum can be measured in saliva of horses and (2) to study the possible changes of these biochemical analytes in saliva of horses affected by acute abdominal disease. A panel of 23 analytes was analytically validated in saliva of horses and possible changes in these analytes in a pilot study with six healthy horses and six horses with acute abdominal disease were evaluated. The analytes with significant changes were then evaluated in a larger population of 20 healthy and 37 diseased horses.

RESULTS

Seven analytes showed significant increases in the pilot study which were confirmed in the larger population. The analytes which showed significant changes, and their median fold increase and significance shown in the larger population were salivary γ-glutamyl transferase (gGT, 2.3 fold, P = 0.001), creatine kinase (CK, 6.2 fold, P < 0.001), urea (2.3 fold, P = 0.001), total bilirubin (2.6 fold, P < 0.001), total proteins (3.2 fold, P < 0.001), phosphorus (P, 4.5 fold, P < 0.001) and alpha-amylase (sAA, 8.5 fold, P < 0.001). Total proteins, P and sAA showed sensitivities higher than 70% at their optimal cut-off points and a specificity of 100% in differentiating between healthy horses and those with acute abdominal disease.

CONCLUSIONS

A panel of 23 biochemical analytes can be measured in saliva of horses, where gGT, CK, urea, total bilirubin, total protein, P and sAA levels are raised in horses with acute abdominal disease.

Salivary alpha-amylase activity and concentration in horses with acute abdominal disease: Association with outcome

BACKGROUND

Salivary biomarkers could be useful to objectively evaluate critical illness and prognosis for survival in horses with acute abdominal disease.

OBJECTIVES

To compare salivary alpha-amylase (sAA) activity and concentration in healthy horses and horses with acute abdominal disease, and evaluate the association between sAA activity and concentration with disease severity and outcome.

STUDY DESIGN

A prospective cohort.

METHODS

sAA activity, measured using a colorimetric commercial kit, and concentration, measured using a Time-resolved immunofluorometric assay, in 25 healthy horses and in 33 horses with acute abdominal disease was compared using an ANOVA. Associations between survival to discharge and sAA activity and concentration and other clinical parameters were examined using univariable logistic regression and Spearman correlation.

RESULTS

sAA activity and concentration were different between healthy (median = 4.3 [2.6-11.2] IU/L and 58.4 [53.4-80.6] ng/mL, respectively) and diseased (median = 29.8 [14.2-168.9] IU/L and 388.3 [189.1-675.8] ng/mL, respectively) (P<0.001). The sAA activity was higher in non-survivors (median = 479.0 [78.7-2064.0] IU/L, n = 8) compared to survivors (median = 19.3 [12.1-103.7] IU/L, n = 25, P<0.001) and sAA activity and concentration correlated (P<0.001) moderately with HR (r = 0.66 and r = 0.61, respectively). sAA activity correlated weakly with salivary cortisol (r = 0.45, P<0.001) and systemic inflammatory response syndrome score (r = 0.43, P<0.05), while activity and concentration correlated (P<0.001) moderately with plasma lactate concentration (r = 0.57 and r = 0.60, respectively). The sAA activity was significantly (P = 0.01) associated with increased risk of nonsurvival.

MAIN LIMITATIONS

Pain scores were not recorded. The sample population was small.

CONCLUSIONS

The sAA activity, but not concentration, shows potential as a biomarker of prognosis for survival in horses with acute abdominal disease. The summary is available in Spanish - see Supporting Information.

Changes in alpha-amylase activity, concentration and isoforms in pigs after an experimental acute stress model: an exploratory study

BACKGROUND

Salivary alpha-amylase (sAA) is considered a non-invasive biomarker of acute stress that can be evaluated by changes in activity and concentration, and also by changes in its isoforms, although this last way of evaluation has never been used in veterinary medicine. This research evaluated the changes of sAA by three different ways in which sAA can be evaluated in an experimental acute stress model in six pigs based in a technique of temporarily restraining. These ways of evaluation were 1) activity by a spectrophotometric assay, 2) concentration by a fluorometric assay, and 3) isoforms of the enzyme by a Western blot.

RESULTS

Although salivary cortisol significantly increased due to the stimulus of stress and all the pigs manifested signs of stress by high-pitched vocalization, sAA activity showed an increase of different degree in the six pigs after the stress stimulus, while sAA concentration showed decreases in four of the six pigs. sAA activity did not correlate with sAA concentration or salivary cortisol, and a low correlation was observed between sAA concentration and salivary cortisol (r = 0.48, p = 0.003). The inter-individual variability was higher in sAA activity than in sAA concentration and salivary cortisol. Finally, three possible isoforms of sAA at 154-160 kDa, 65-66 kDa and 59-60 kDa were observed that showed different dynamics after the stress induction.

CONCLUSIONS

Although this pilot study's results should be taken with caution due to the low sample size, it reveals a different behavior between sAA activity and concentration in pig after an acute stressful stimulus leading to evident external signs of stress by high-pitched vocalization, and opens a new field for the evaluation of possible selected isoforms of sAA as potential biomarkers of stress.