When incubated with solutions of hydrogen peroxide, erythrocytes of stress-susceptible pigs produced more by-products of lipid peroxidation (as measured as thiobarbituric acid-reactive substances [TBARS]) than did erythrocytes from stress-resistant pigs. Using this technique, discrimination between the 2 pig types was absolute at hydrogen peroxide concentrations of 0.9 and 1.5%. This was in contrast to other methods of identifying stress-susceptible pigs, such as osmotically induced erythrocyte lysis and the determination of plasma pyruvate kinase and creatine kinase activities, for which considerable overlap of data was observed between pig types. The increased TBARS production by erythrocytes was further evidence for the existence of an antioxidant abnormality in stress-susceptible pigs. However, because there were no discernible differences in the major blood antioxidant-related values between stress-susceptible and stress-resistant pigs, the nature of the defect remains unclear. The production of TBARS by erythrocytes when incubated with hydrogen peroxide provides an improved method for identifying stress-susceptible pigs.

The relation between average duodenal mast cell count, duodenal mucosal mast cell numbers, duodenal connective tissue mast cell numbers, circulating basophil numbers, heterophil-to-lymphocyte ratio, and lesion score were studied to gain an understanding of the events that may lead to intestinal lesion formation associated with hemorrhagic enteritis virus (HEV) infection. Changes in vascular permeability in the duodenum in birds inoculated with HEV were examined, using colloidal carbon and ferritin as vascular markers. Turkeys inoculated with HEV had significantly (P < 0.05) higher duodenal mast cell counts than did noninfected controls. Birds inoculated with HEV had significantly (P < 0.05) more mucosal mast cells than did phosphate-buffered saline solution-inoculated birds. Connective tissue mast cell and basophil numbers were unaffected by viral inoculation. Thermal stress did not have significant effect on lesion severity, but did increase number of birds that developed the characteristic intestinal lesions. The heterophil-to-lymphocyte ratio was significantly (P < 0.05) higher in HEV-inoculated birds, compared with phosphate-buffered saline solution-inoculated controls. Increase in vascular permeability was only detected in HEV-inoculated birds with intestinal lesions. Results indicate that mast cells, and the vasoactive mediators contained within mast cells, may be important in the early manifestation of HEV infection. They also provide a possible mechanism through which biochemical and physiologic changes characteristic of HEV infection can occur.

There is a balance between oxidative stress, antioxidant capacity and immune response. Their roles in physiological and behavioural mechanisms are important for the maintenance of the organism’s internal equilibrium. This study aimed to evaluate the antioxidant effects of the exogenous alga Spirulina platensis (Arthrospira platensis) in a stress-induced rat model, and to describe its possible mechanism of action.

The present study evaluated the dietary supplementation with essential oil of Lippia alba on the hemato-immunological parameters of Nile tilapia (Oreochromis niloticus) submitted to acute inflammation induced by carrageenin injection in the swim bladder. For a period of 45 days, 96 fish were divided in four treatments in triplicate, as follows: fish fed supplemented diet with essential oil of L. alba (4 mL kg-1 dry ration) injected with carrageenin; fish fed supplemented diet with cereal alcohol injected with carrageenin; fish fed unsupplemented diet with essential oil injected with carrageenin; fish fed unsupplemented diet and noninjected. Cortisol levels, erythrogram, leukogram and the inflammatory infiltrate were analyzed 6 h after inflammatory stimulus. Carrageenin-injected fish showed acute inflammatory reaction in the swim bladder characterized by higher infiltrate of neutrophils and monocytes. The circulating neutrophils number was significantly higher in fish fed L. alba when compared to other treatments. No difference in cortisol levels was found. For dose, time and administration form tested, supplementation with essential oil of L. alba did not present anti-inflammatory activity. On the other hand, influence of dietary supplementation was observed on the neutrophils number after induced aerocystitis highlighting its immunomodulatory characteristic.

Brazil is the world’s largest exporter and third largest producer of chicken meat. To maintain competitiveness, the productive sector must always be alert to consumer demands, and concern about animal welfare is a growing tendency. Aspects involving animal welfare are especially critical in the slaughter of broiler chickens. This study evaluated the stunning of chickens in a CO2-enriched atmosphere chamber to reduce bird stress, comparing with electrical water bath stunning, the most usual desensitization method used in chicken slaughter. The reaction of birds when exposed to a high CO2 concentration (30%) and to a 10% initial CO2 level, gradually elevated to 30% was compared. The effect of mixing argon with CO2 was also evaluated, always aiming to reduce the discomfort of birds. In all the gas stunning parameters evaluated, evident discomfort reactions before stunning were observed in about two thirds of the birds, but the blood levels of corticosterone and glucose, used as stress indicators, indicated that gas increased the birds’ welfare. Gas exposure time required to stun the birds and time to regain consciousness after exiting the gas chamber presented a wide variation. Controlled atmosphere stunning method facilitated bird handling during slaughter, but more studies will be necessary to develop this technological alternative and make it viable for industrial use.

Surgical procedures in pet animals are usually associated with some degree of stress and pain. Hospitalization is one stress-triggering factor. The present study aimed to evaluate the degree of stress and pain during hospitalization of female dogs submitted to elective ovariohysterectomy (OVH) and to investigate the influence of hospitalization on the stress of these animals. Fifteen young adult crossbreed female dogs were divided into two groups: eight animals without surgery (Group 1 - control) and seven animals submitted to surgery (Group 2 - OVH). Pain and stress were evaluated. Visual analogue scale (VAS), simple descriptive pain scale (SDS) and modified Glasgow pain scale (MGPS) were used. Serum cortisol (μg/dL) and glucose (mg/dl) were also measured. No statistical difference was observed for cortisol (μg/dL) between the two groups. Despite the absence of statistical difference between groups and times, mean serum cortisol (μg/dL) values exceeded the normal values for the canine species at various times evaluated. Hyperglycemia was only observed at T4 in the OVH group. It was concluded that the hospitalization of animals was more relevant in the establishment of stress than the surgical procedure and associated pain. The influence of stress was a relevant factor in the results of assessments carried out using the MGPS.

The intensification of cattle production has raised concern for animal welfare due to the stress that is associated with farming practices. The welfare of an animal is determined by the animal’s ability to cope with or adapt to its continuously changing environment and the biological cost that is associated with this adaptation and maintenance. Stressors arise from various psychological, physiological and physical aspects of farming practices due to management and human–cattle interactions. Measuring the activity of the hypothalamopituitary-adrenocortical (HPA) axis with plasma cortisol levels is a useful method for determining the effects of stress on animals as it is stimulated at the onset of a perceived stress. The activation of the HPA axis affects various target tissues or systems and can result in suppression of the immune system, increased susceptibility to disease and adverse effects on reproductive success in prenatal and neonatal calves. Although some levels of stress associated with farming practices are unavoidable, improvements in farming methods need to be implemented in order to maintain or increase the efficiency of cattle production in a way that does not compromise the welfare of the animal.

In current research guidelines, much focus is placed on ethical management of animals and the application of principles of reduction, refinement and replacement. Of these refinements through environmental enrichment is an important aspect when housing primate to prevent behavioural problems. In this study, we investigated the co-housing of domestic cats and vervet monkeys as a novel method of enrichment based on the cohabitation and stress alleviation effect of horses housed with goats and from seeing cats cohabitating with vervet monkeys in an animal sanctuary. The study used a habituation method whereby the cats were stepwise introduced to the monkeys by sight and smell but with physical separation. Assessment included changes in behaviour, weight and faecal glucocorticoid metabolite (fGCM) concentrations over time. On the first day of housing, the vervets whilst inquisitive kept their distance. The vervets housed in cages that were closest to the cats were the most active and during the first minute of introduction made more alarm calls, which stopped a few days later. The fGCMs were non-significantly different. The results of this study provide evidence that vervet monkeys and domestic cats could potentially be housed together without overt aggression. We thus suggest further observations to ascertain if the co-housing could have long-term benefits for vervet monkeys, from the companionship that would be offered by the cats.