Assay of alterations in oxidative stress markers in pigs naturally infested with Sarcoptes scabiei var. suis

Evidence underscoring immunological and clinical pathological changes associated with Sarcoptes scabiei infection: synthesis and meta-analysis

Background

Sarcoptes scabiei is one of the most impactful mammalian parasites. There has been much research on immunological and clinical pathological changes associated with S. scabiei parasitism across a range of host species. This rich body of literature is complex, and we seek to bring that complexity together in this study. We first (1) synthesise narrative reviews of immunopathological relationships to S. scabiei infection to construct overarching hypotheses; then (2) undertake a systematic meta-analysis of primary literature on immunological and clinical pathological changes; and lastly (3) contrast our findings from the meta-analysis to our synthesis from narrative reviews.

Methods

We synthesised 55 narrative reviews into two overarching hypotheses representing type I and type IV immune responses to S. scabiei infection. We then systematically extracted all literature reporting immunological variables, acute phase proteins, oxidant/antioxidant status, and erythrocytic, hepatological and nephrological changes, calculating 565 effect sizes between controls and sarcoptic mange affected groupings, refining (simplifying) hypotheses from narrative reviews.

Results

Immunological and clinical pathological parameters were most often studied in dogs (n = 12) and humans (n = 14). Combining immunological and clinical pathological information across mammalian species (n = 19) helped yield general insights into observed disease responses. This is evidenced by interspecific consensus in 27 immunological and clinical pathology variables (6/26 type I hypersensitivity, 3/20 type IV hypersensitivity, 6/10 oxidant/antioxidant status, 3/6 acute phase protein, 4/7 erythrocytic, and 5/10 hepatological/nephrological).

Conclusions

Elevated IgE, eosinophils and mast cells in type I hypersensitivity response corresponded to what was described in narrative reviews. Results from type IV hypersensitivity response suggested typical antibody response, however cell-mediated response was less evident. Some consensus of acute phase protein response and shifted oxidant/antioxidant balance and slight evidence of anemia. We highlight the need for mange/scabies studies to more routinely compare immunological and clinical pathological changes against controls, and include collection of a more standardised suite of variables among studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07635-5.

Seroprevalence of Sarcoptes scabiei in Free-Ranging Black Bears (Ursus americanus) in Eastern North Carolina, USA

Recent sarcoptic mange epizootics have affected free-ranging black bears (Ursus americanus) in the northeastern US, but not in North Carolina. To determine whether black bears in eastern North Carolina have exposure to Sarcoptes scabiei, serum samples from hunter-harvested black bears (n=45) were collected and evaluated for antibodies using a commercial enzyme-linked immunosorbent assay previously validated in black bears. No dermal lesions consistent with sarcoptic mange were identified in the sampled bears. The seroprevalence among these asymptomatic bears was 18%, with no significant difference between sexes or association with age. This suggests that exposure to Sarcoptes scabiei occurs within the population, and highlights the importance of serosurveys in regions without a history of clinical mange.

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.

Biomarkers of oxidative stress in saliva in pigs: analytical validation and changes in lactation

BACKGROUND

Biomarkers of oxidative stress in pigs have been measured in serum/plasma samples. However, blood collection in pigs can be highly stressful to the animals. Saliva is a biological fluid with several advantages in pigs over blood, since it can be easily collected without stress to the animals, being therefore an ideal sample in this species. The objective of this study was the validation of assays for the evaluation of oxidative stress status in saliva of pigs. For this purpose, three assays commonly used to evaluate the total antioxidant capacity (TAC): trolox equivalent antioxidant capacity (TEAC), cupric reducing antioxidant capacity (CUPRAC), and ferric reducing ability of plasma (FRAP)), one individual antioxidant (uric acid) and two assays to evaluate oxidant concentrations (advanced oxidation protein products (AOPP) and hydrogen peroxide (H2O2)) were measured and validated in porcine saliva. In addition, the possible changes of these assays in sows' saliva during lactation were be studied.

RESULTS

The methods had intra- and inter-assays coefficient of variation lower than 15%. They also showed an adequate linearity and recovery, and their detection limits were low enough to detect the analytes in saliva of pigs. Overall the analytical validation tests showed that the assays used in our study are valid and reliable for the evaluation of oxidative stress in porcine saliva. In addition, it was observed that these salivary biomarkers can change in a situation of oxidative stress such as lactation in sows.

CONCLUSIONS

All assays for salivary biomarkers of oxidative stress evaluated in this study have demonstrated a high analytical accuracy and low imprecision. In addition, it has been observed that these biomarkers showed significant changes in a situation of oxidative stress such as lactation in sows. Therefore, this study opens a new possibility of using saliva as a non-invasive sample to evaluate oxidative stress in pigs.

Evaluation of oxidant/antioxidant balance in Iberian ibex (Capra pyrenaica) experimentally infested with Sarcoptes scabiei

Oxidative stress (OS) is an imbalance between radical-generating and radical scavenging activity, resulting in oxidation products and tissue damage. Although some studies have been done in other species, there is a lack of information about the oxidative/antioxidant status in the Iberian ibex (Capra pyrenaica) affected by sarcoptic mange. To clarify this fact, albumin, catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), paraoxonase-1 (PON-1), glutathione reductase (GR), reduced glutathione (GSH): oxidized glutathione (GSSG) ratio, thiobarbituric acid reactive substances (TBARS) and total oxidant status (TOS) concentrations were measured in peripheral blood of ibexes experimentally infested with Sarcoptes scabiei (n=25), as well as in the healthy control group (n=14). During the course of the experiment, the infected ibexes were visually assigned to four categories according to the percentage of skin surface affected by mites. In the infested ibexes, the levels of albumin, PON-1, CAT, SOD, GSH-Px and GSH:GSSG ratio showed a significant (p<0.01) decrease with disease progression. With respect to the control group, this decrease was significantly (p<0.001) lower in the more severe clinical stages. No significant changes were observed in GR activity during disease or with respect to the control group. Conversely, the concentrations of TOS and TBARS increased with lesion severity, and with respect to the control group, this increase was significant (p<0.01) in the more advanced stages of the infection. Additionally, to explore the possible effects of sex, age, haplotype, mange status, and days post infection (dpi) on each of the OS biomarkers, generalized additive mixed models were applied. According to our results, the mange status and dpi explained the highest percentages in the observed changes in the biomarkers analyzed, whereas the haplotype only influenced the observed variability of albumin and TOS. The contribution of sex and age was not significant in any of the OS biomarkers. From the present study, it may be concluded that sarcoptic mange infestation increases OS and decreases antioxidant status in ibex. This imbalance may contribute to the pathogenesis of this disease.

Oxidative Stress and Histological Alterations of Chicken Brain Induced by Oral Administration of Chromium(III)

This experiment was conducted to investigate the oxidative stress in chickens exposed to different concentrations of chromium trichloride (CrCl3) in drinking water. Seventy-two Hylan Brown male chickens were randomly divided into four groups: three experimental groups and one control group. The experimental groups were exposed to three different doses (50 % LD50, 25 % LD50, and 12.5 % LD50) of CrCl3 mg/kg body weight for 42 days, while the control group was given the equivalent water. The activities of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and non-enzymatic index (glutathione, total antioxidant capacity, malondialdehyde, and hydrogen peroxide) were measured after obtaining the brain samples. Results suggested that 50 % LD50 chromium(III) significantly increased (P < 0.05) the contents of malondialdehyde and hydrogen peroxide. The antioxidant enzyme activities, total glutathione concentration, and total antioxidant capacity decreased significantly (P < 0.05) compared with those of the controls and were consistent with the increase in dosage and time. Additionally, extensive histological alterations were observed in the chicken brain, such as the vacuolization and nuclear condensation of the neurons. These results indicated that exposure to high-dose CrCl3 for a certain time could induce the occurrence of oxidative stress and histological alterations.