The activity of several cuproenzymes in relation to the immune system was examined in serum and blood cells from bovines with molybdenum-induced copper deficiency. Five female cattle were given molybdenum (30 ppm) and sulfate (225 ppm) to induce experimental secondary copper deficiency. Ceruloplasmin activity was determined in serum. The Cu,Zn-superoxide dismutase and cytochrome c oxidase activities were measured in peripheral blood lymphocytes, neutrophils, and monocyte-derived macrophages. Copper deficiency was confirmed from decreased serum copper levels and the animals with values less than 5.6 micromol/L were considered deficient. The content of intracellular copper decreased between 40% and 70% in deficient cells compared with the controls. In copper-deficient animals, the serum ceruloplasmin activity decreased to half of the control value. Both of them, the Cu,Zn-superoxide dismutase and the cytochrome c oxidase activities, undergo a significant reduction in leukocytes, showing differences among diverse cell populations. We concluded that the copper deficiency alters the activity of several enzymes, which mediate antioxidant defenses and ATP formation. These effects may impair the cell immune functionality, affecting the bactericidal capacity and making the animals more susceptible to infection.

No abstract

Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen that causes gastroenteritis and Hemolytic Uremic Syndrome. Cattle are the main animal reservoir, excreting the bacteria in their feces and contaminating the environment. In addition, meat can be contaminated by releasing the intestinal content during slaughtering. Here, we evaluated the safety and immunogenicity of a vaccine candidate against STEC that was formulated with two chimeric proteins (Chi1 and Chi2), which contain epitopes of the OmpT, Cah and Hes proteins. Thirty pregnant cows in their third trimester of gestation were included and distributed into six groups (n = 5 per group): four groups were administered intramuscularly with three doses of the formulation containing 40 µg or 100 µg of each protein plus the Quil-A or Montanide™ Gel adjuvants, while two control groups were administered with placebos. No local or systemic adverse effects were observed during the study, and hematological parameters and values of blood biochemical indicators were similar among all groups. Furthermore, all vaccine formulations triggered systemic anti-Chi1/Chi2 IgG antibody levels that were significantly higher than the control groups. However, specific IgA levels were generally low and without significant differences among groups. Notably, anti-Chi1/Chi2 IgG antibody levels in the serum of newborn calves fed with colostrum from their immunized dams were significantly higher compared to newborn calves fed with colostrum from control cows, suggesting a passive immunization through colostrum. These results demonstrate that this vaccine is safe and immunogenic when applied to pregnant cows during the third trimester of gestation.

No abstract

The objectives of this study were to evaluate the activity of antioxidant systems in the hepatic tissues of steers experimentally subjected to a restricted diet. Hence, the activities of superoxide dismutase (SOD) and reduced glutathione (GSH) and lipid peroxide levels were measured. Nine male Holstein steers were used. They were separated in two groups: three steers in group 1 (control) and six steers in group 2, which were subjected to a restricted diet that covered only 60% of the maintenance requirements. After 30 days, the animals in both groups were killed and studies were completed. Both the CuZn-SOD and the glucose-6-phosphate dehydrogenase activities were significantly decreased (p < 0.05) in group 2, reaching 68% and 60%, respectively, of the concentrations found in group 1. The concentration of GSH in group 2 was 6.71+/-0.9 nmol/mg protein, which was significantly lower (p < 0.01) than that of the controls, 25.7+/-2.4 nmol/mg protein. In addition, the lipid peroxide levels were significantly increased (p < 0.01) in group 2, being 50-60% higher than that in group 1. These results showed that the poor nutritional status caused modifications to the enzymatic antioxidant systems, with a lower ability to reduce oxidative compounds and a state of lipid peroxidation.