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

Salivary alpha-amylase stress reactivity in advanced-aged marmosets (Callithrix jacchus): Impacts of cognitive function and oral health status

Salivary alpha-amylase (sAA) is an enzyme found in saliva and is considered a noninvasive biomarker for sympathetic nervous system activity. While a wide range of sAA activity in response to stress has been reported in nonhuman primates, the effects of stress on sAA activity in common marmosets are still unknown. We tested the hypothesis that advanced age and cognitive function may have an impact on stress-related sAA reactivity in marmosets. Thirteen marmosets (nine males and five females) had saliva samples collected during a stressful condition (manual restraint stress) at two different time points, with a 60-min interval. On the next day, the animals underwent the object recognition test (ORT, a type of cognitive test), and then oral examinations. The animals were categorized into two age groups: old (10-13 years), and very old (15-22 years). Irrespective of age, sAA levels showed a significant difference between T1 (mean 2.07 ± 0.86 U/mL) and T2 samples (mean 1.03 ± 0.67 U/mL), with higher values observed at T1 (p < 0.001). The intra-assay coefficients of variation (CV) for low and high sAA concentrations were 10.79% and 8.17%, respectively, while the interassay CVs for low and high sAA concentrations were 6.39% and 4.38%, respectively. Oral health issues were common but did not significantly impact sAA levels. The ORT indicated that the animals could recognize an object placed in the cage 6 h after familiarization. In conclusion, all marmosets showed a higher sAA concentration in the first saliva sample as compared to the second saliva sample collected 1 h later, indicating adaptation to stress. No significant differences in sAA levels were observed between sexes, ORT performance, or oral health. Our results indicate that autonomic responsivity and cognitive (memory) functions were preserved even in very old marmosets.

Transcriptome-based analysis of early post-mortem formation of pale, soft, and exudative (PSE) pork

Pale, soft, and exudative (PSE) meat can cause consumer dissatisfaction and economic losses. This study determined meat quality, glycolytic enzyme activity, and differential gene expression in the longissimus lumborum (LL) and semimembranosus (SM) of normal and PSE pork carcasses. The SM did not result in PSE meat. Hexokinase, lactate dehydrogenase, and pyruvate kinase activities were lower in the SM of PSE carcasses than in the normal carcasses. Functional enrichment analysis revealed that immune, inflammatory, and muscle fibre genes were significantly enriched in PSE pork. More specifically, PPP1R3G and MSS51 may be key genes regulating pork quality in the SM. Meanwhile, the differential expression of PLVAB, ADIPOQ, LEP, MYH4, MYH7, MYL3, MYL6B, FOS, ATF3, and HSPA6 may induce PSE formation in the LL. These results may provide insights into PSE pork formation mechanisms and reveal candidate genes for improving meat quality after validation.

Changes in a Comprehensive Profile of Saliva Analytes in Fattening Pigs during a Complete Productive Cycle: A Longitudinal Study

Simple Summary

The aim of this study was to evaluate whether a panel of 29 salivary biomarkers of stress, immunity, inflammation, redox homeostasis and other physiological functions can change in healthy fattening pigs when monitoring the different phases of their productive cycle and can be influenced by various sources of variations such as gender and performance parameters. Several analytes showed changes due to the productive cycle, with a majority of the analytes showing higher values at lactation and at the beginning of nursery. Additionally, differences were seen due to sex. These differences can be related in some cases with performance parameters and should be taken into consideration for an appropriate interpretation of the analytes.

Abstract

A comprehensive panel of 29 salivary analytes was measured in fattening pigs to evaluate its possible changes along their productive cycle. The identification of those changes would allow a better interpretation of the results according to the productive phase of the animal. Saliva samples were obtained from 49 Large-White pigs (24 females, 25 males) in suckling phase, at the beginning and the end of the nursery phase, and at the beginning and the end of the growing phase. Several analytes changed according to the phase of the productive cycle, with most of the analytes showing higher values at lactation and at the beginning of nursery. Additionally, differences were seen due to sex. When possible relations between performance parameters and analytes were evaluated, significant positive but weak relationships were found between weight at birth and salivary γ-glutamyl transferase, and between back-fat thickness and salivary lactate dehydrogenase. In conclusion, differences in the values of salivary analytes can be found in fattening pigs depending on the productive phase and sex of the animals.

Basics for the potential use of saliva to evaluate stress, inflammation, immune system, and redox homeostasis in pigs

The use of saliva as a biological sample has many advantages, being especially relevant in pigs where the blood collection is highly stressful and painful, both for the animal and the staff in charge of the sampling. Currently one of the main uses of saliva is for diagnosis and detection of infectious diseases, but the saliva can also be used to measure biomarkers that can provide information of stress, inflammation, immune response and redox homeostasis. This review will be focused on the analytes that can be used for such evaluations. Emphasis will be given in providing data of practical use about their physiological basis, how they can be measured, and their interpretation. In addition, some general rules regarding sampling and saliva storage are provided and the concept of sialochemistry will be addressed. There is still a need for more data and knowledge for most of these biomarkers to optimize their use, application, and interpretation. However, this review provides updated data to illustrate that besides the detection of pathogens in saliva, additional interesting applicative information regarding pigs´ welfare and health can be obtained from this fluid. Information that can potentially be applied to other animal species as well as to humans.

The markers of stress in swine oral fluid

Introduction

The study measured the hormonal and protein markers of acute stress, those of oxidative stress and total antioxidant capacity (TAC) in swine oral fluid, determined which of these parameters would be the most appropriate for future livestock welfare assessment and established the time when the samples should be taken.

Material and Methods

Stress was induced in 7 out of 14 castrated six-week-old Danbred×Duroc pigs by immobilisation on a nasal snare at 8 a.m., 1 p.m., and 6 p.m. and samples were taken both directly after the stressor was applied and 30 min later. The remaining pigs were the control group, which were not immobilised; their samples were taken at the same times. The concentrations of hormones and malondialdehyde (MDA) were measured using liquid chromatography with tandem mass spectrometry, while those of alpha-amylase and TAC were measured using spectrophotometry.

Results

The levels of cortisol and cortisone increased with statistical significance immediately after the acute stress response and 30 min later. A cut-off value set at 0.25 ng/mL cortisol concentration was capable of distinguishing between the stressed and control groups with 100% accuracy in evening samples and 95% accuracy overall. Prednisolone was not present, and the levels of testosterone and corticosterone were low and not distinctive. Alpha-amylase became significantly more concentrated during stress induction and 30 min later. The TAC and MDA levels rose after the stress but without statistical significance.

Conclusion

The most suitable markers of acute stress were cortisol, cortisone and alpha-amylase. Oral fluid is a reliable material for monitoring the level of pigs’ stress and should be collected in the evening.

Salivary stress markers in dogs: Potential markers of acute stress

Along with the growing awareness of psychological stress in companion animals, several treatments have become available to address fear- and anxiety-related behaviors in dogs. To detect vulnerable individuals and apply effective treatments, reliable evaluations that can quantify individual stress responses are in high demand. To develop measurable variables that have clinical applications, more investigations are needed to increase our knowledge. When stress responses are activated by the sympathetic-adrenal-medullary (SAM) and hypothalamic-pituitary-adrenal (HPA) axes, the immune system is also activated. Although the peripheral cortisol level is commonly used as a stress biomarker, it primarily reflects the HPA axis response and does not sufficiently reflect the complexity of the stress response. Thus, this review primarily focuses on the available salivary biomarkers that mainly reflect the acute stress response through the activity of the SAM axis and the immune system in dogs. We hope that this review will promote the validation of these biomarkers in dogs and aid in the development of future studies to evaluate stress responses in dogs.

Changes in saliva analytes during pregnancy, farrowing and lactation in sows: A sialochemistry approach

Salivary biomarkers were studied in 17 healthy Large White sows from early gestation to the end of lactation. Saliva samples were obtained at 34 ± 3 days from insemination (G30), 24 ± 4 days before farrowing (G90), within the first 24 h after farrowing (L1) and at the end of a lactation period of 21 days (L21). The measurements in saliva included stress-related biomarkers (cortisol, chromogranin A, α-amylase, butyrylcholinesterase [BChE] and lipase [Lip]), inflammatory biomarkers (adenosine deaminase isoenzymes 1 [ADA1] and 2 [ADA2], and haptoglobin [Hp]) and oxidative stress biomarkers (cupric reducing antioxidant capacity, trolox equivalent antioxidant capacity, ferric reducing ability, uric acid, advanced oxidation protein products [AOPP] and hydrogen peroxide [H₂O₂]), as well as routine biochemistry analytes (aspartate aminotransferase [AST], alkaline phosphatase [ALP], γ-glutamine transferase [GGT], lactate dehydrogenase [LDH], creatine kinase [CK], urea, creatinine, triglycerides, lactate, calcium and phosphorus). The main changes were observed at farrowing, with increases in biomarkers of stress (cortisol and BChE), inflammation (ADA isoenzymes and Hp) and oxidative stress (AOPP and H₂O₂), as well as muscle and hepatic enzymes (CK, AST, ALP, GGT and LDH). Lactate and triglycerides increased at the end of gestation and remained at high concentrations until the end of lactation. Lip was higher in gestation than at lactation. Thus, changes in biomarkers of stress, immune function, oxidative stress, hepatic and muscle integrity, and energy mobilization occur in sow saliva during pregnancy, farrowing and lactation. These changes, caused by physiological conditions, should be taken into consideration when these biomarkers are used for the evaluation of sow health and welfare.

Salivary Protein Profile and Food Intake: A Dietary Pattern Analysis

Saliva research has gained interest due to its potential as a source of biomarkers. One of the factors inducing changes in saliva, in the short term, is food intake, and evidence exist about changes in salivary proteome induced by some food components. Since this topic of research is in its early stages, it was hypothesized that saliva protein composition could be associated with different levels of adherence to dietary patterns that contain higher amounts of plant products. The aim of the present study was to test this hypothesis, in adults, by comparing salivary protein electrophoretic profiles of individuals with different diet characteristics, particularly dietary patterns (DP) that exhibit different proportions of animal and plant-based products. Dietary habits were assessed in 122 adults (61 from each sex, with ages ranging from 20 to 59 years) using Food Frequency Questionnaires. To identify the dietary patterns, a principal component analysis was used. Individual's non-stimulated saliva was evaluated for flow rate, pH, protein concentration, α-amylase activity, and electrophoretic protein profiles. Seven dietary patterns (DP) were identified. Salivary amylase enzymatic activity was positively associated with animal-based and starchy foods DP, and with plant-based fatty foods without wine DP. At the same time, protein bands containing amylase and type S cystatins were positively associated with the cheese/yoghurt and wine DP. Our results support the association of salivary proteomics and different dietary patterns and highlight the need of considering food consumption habits in studies using saliva, since this is a factor associated with variations in the composition of this fluid.

Effect of reduction and alkylation treatment in three different assays used for the measurement of oxytocin in saliva of pigs

Oxytocin is a hormone that is increasingly being used for welfare evaluation in animals. Although several types of samples have been used for oxytocin measurement, saliva can be a suitable option for pigs producing less stress than blood sampling. In this study, 3 different methods for oxytocin measurements, 2 based on alphaLISA technology (one with a monoclonal and other with a polyclonal antibody) and one commercially available kit, were compared in saliva of pigs. These methods were used in saliva samples obtained from female pigs at 3 different days during gestation and lactation, with and without a reduction/alkylation (R/A), which is a procedure for breaking the links between oxytocin and proteins of the sample. The assays showed a different behavior after the R/A procedure, with no significant changes in the oxytocin results in case of the alphaLISA monoclonal method, a significant decrease with the alphaLISA polyclonal method, and a significant increase with the commercial kit. Although all assays showed a similar tendency in detecting the changes in oxytocin during gestation and lactation, they showed changes of different magnitude and statistical signification. This report indicates that different assays can measure different forms of oxytocin present in saliva and can have a different behavior after R/A of the sample and when are used to measure oxytocin in gestation and lactation.

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.

Where Do We Stand in the Domestic Dog ( Canis familiaris ) Positive-Emotion Assessment: A State-of-the-Art Review and Future Directions

Although there have been a growing number of studies focusing on dog welfare, the research field concerning dog positive-emotion assessment remains mostly unexplored. This paper aims to provide a state-of-the-art review and summary of the scattered and disperse research on dog positive-emotion assessment. The review notably details the current advancement in dog positive-emotion research, what approaches, measures, methods, and techniques have been implemented so far in emotion perception, processing, and response assessment. Moreover, we propose possible future research directions for short-term emotion as well as longer-term emotional states assessment in dogs. The review ends by identifying and addressing some methodological limitations and by pointing out further methodological research needs.

Changes in oxytocin concentrations in saliva of pigs after a transport and during lairage at slaughterhouse

Oxytocin is associated with reproductive physiology but also with welfare and positive emotions. In this study, oxytocin was measured in saliva samples of 45 pigs that were collected before being transported to the slaughterhouse, at the time of arrival and 4 h after arrival to the slaughterhouse. Two previously validated assays, one that measures free oxytocin and other that measures oxytocin linked to proteins, were used. In addition, cortisol, salivary alpha-amylase (sAA), total esterase activity (TEA), butyrylcholinesterase (BChE) and lactate dehydrogenase (LDH), which are biomarkers associated with stress and pain in pigs, were measured. The results showed a decrease in free and protein-linked oxytocin concentrations at 4 h after transport compared with the time before transport, while cortisol, sAA, TEA, BChE and LDH showed an increase at 4 h after transport compared with the time before transport. Based on these results it can be concluded that the transport and lairage at slaughterhouse in the conditions of this study produce a decrease in oxytocin in the saliva of pigs that could indicate a reduced emotional well-being.

Salivary D-dimer in pigs: Validation of an automated assay and changes after acute stress

D-dimer is a peptide found in serum and is derived from the degradation of blood clots. Even though it has been analysed in human saliva, D-dimer has not been previously evaluated in the saliva of any veterinary species, and its source and role remain unknown. The objectives of this research were firstly, to validate the use of an automated method for the measurement of D-dimer in porcine saliva, and secondly, to evaluate whether D-dimer concentration changes in pig saliva after an acute stress stimulus. For this purpose, a complete analytical validation of a commercially-available immunoturbidimetric assay was carried out. In addition, an experimental acute stress model was induced in 11 pigs based on a technique involving restraint by nose-snare immobilisation for 1 min. Saliva samples were subsequently collected at different times and D-dimer, salivary alpha-amylase (sAA) and cortisol were assessed in order to evaluate changes in its concentrations after the stress induction. The D-dimer automated assay showed adequate reproducibility and sensitivity, with coefficients of variation below 10% and a limit of quantification of 0.167 μg/mL fibrinogen equivalent units (FEU). It also showed a high accuracy, determined by linearity under dilution and recovery tests. In the stress model, a significant increase (P < 0.05) in salivary D-dimer 15 min after the stress stimulus and a positive correlation between D-dimer and sAA (r = 0.51; P < 0.001) were observed. These results indicate that D-dimer can be measured in porcine saliva with an automated method and suggest that its concentration can be influenced by stressful conditions.

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.

An Appraisal of Methods for Measuring Welfare of Grazing Ruminants

Although disturbances in body function of animals can be measured to determine whether a state of stress may exist, there is growing interest in finding ways to assess their emotional status as an indicator of good or bad welfare status. Generally it is easier to determine poor states of well-being than positive ones. For grazing ruminants some indicators of well-being include absence of illness, good growth and productivity, and longevity. Motion detectors can provide automated remote monitoring of behavior and it is likely that there will be advances in the interpretation software to increase the utility of this technology for assessing well-being. Cortisol levels in body fluids, feces and pelage are prominent as a marker of poor animal welfare, but like many of the other objective measures that are used, are not wholly reliable at the individual animal level. These other measures include: plasma serotonin, heart rate variation, infra-red thermography, cytokines, salivary alpha amylase, and acute phase proteins. Use of automated facial expression recognition may supplement electrophysiological recording as means to quantify the pain experience of animals. Although the measures described in the literature do not necessarily provide the final answer for determination of welfare in grazing ruminants, they all have some merit and deserve further investigation.

Application of a score for evaluation of pain, distress and discomfort in pigs with lameness and prolapses: correlation with saliva biomarkers and severity of the disease

A score system was used to evaluate pain, distress and discomfort in healthy pigs and pigs with two different diseases: lameness and rectal prolapse. In addition, correlations between the results of this score and a panel of salivary biomarkers and severity of disease were studied. This panel included biomarkers of stress (cortisol, salivary alpha-amylase (sAA), total esterase activity (TEA), butyrylcholinesterase (BChE) and lipase (Lip)), immunity (adenosine deaminase isozymes 1 (ADA1) and 2 (ADA2)) and oxidative status (uric acid (UA), Trolox equivalent antioxidant capacity (TEAC), cupric reducing antioxidant capacity (CUPRAC), ferric reducing ability of saliva (FRAS), advanced oxidation protein products (AOPP) and hydrogen peroxide (H₂O₂)). Based on their score, diseased animals were subdivided in those without and with evident pain. Lame pigs and prolapsed pigs with pain showed higher salivary levels of cortisol, sAA, TEA, BChE, ADA1 and ADA2 compared with the healthy pigs. In addition, the prolapsed pigs with pain showed higher levels of FRAS, AOPP and H₂O₂ compared with the healthy animals. Salivary cortisol, TEA, BChE, ADA isozymes 1 and 2, FRAS and AOPP correlated with the pain score. This five-point pain score system can be easily applied to lame and prolapsed pigs, and salivary biomarkers could be used as an additional tool for pain assessment in those pigs.

Changes in saliva proteins in two conditions of compromised welfare in pigs: An experimental induced stress by nose snaring and lameness

The aim of this study was to identify biological pathways and proteins differentially expressed in saliva of pigs in two conditions of compromised welfare: an acute stress consisting of restraint with a nose snare and in pigs with lameness which is a highly frequent problem in the swine industry. For this purpose, high-resolution quantitative proteomics based on Tandem Mass Tags labelling was used. Four proteins showed significant differences in the conditions of compromised welfare, namely cornulin, the heat shock protein 27 and lactate dehydrogenase (LDH), that showed significant increases, whereas immunoglobulin J chain showed a significant decrease. LDH, which was the protein that showed the highest differences, was selected for validation and clinical evaluation as a diagnostic biomarker. Significant changes in this protein were observed between pigs restrained with a nose snare and pigs with lameness compared with healthy pigs when measured with available commercial assays in a larger population of pigs. In conclusion, this study reports that in situations of compromised welfare on farm, such as acute stress and lameness in pigs, there are changes in proteins and metabolic pathways in saliva, and describes a series of proteins that could potentially be used as biomarkers for both short term acute stress and longer term chronic stress of lameness. These biomarkers would have the advantage of being measured in saliva by a noninvasive and not stressful collection sampling procedure.

Immunostimulatory effect of kumquat (Fortunella crassifolia) and its constituents, β-cryptoxanthin andR-limonene

The active constituents of kumquat in NK cell activation and anti-stress effects are β-cryptoxanthin andR-limonene.