Jhonatan P. Boito

Evaluation of tea tree oil for controlling Rhipicephalus microplus in dairy cows.

Our research aimed to test the effects of Melaleuca alternifolia oil (pure and in nanocapsules) in the control of Rhipicephalus microplus in dairy cattle. For this purpose, the in vivo studies used 15 cows distributed in three different groups with the same number of animals. Five cows remained untreated (Group A), representing the control group; other five cows were sprayed with TTO (at 5%) in its pure form (Group B); and five cows were sprayed with nanocapsules of TTO (at 0.75%) (Group C). On days 1 and 4 post-treatments (PT), all cows had their ticks counted. On day 1 PT, two ticks from each cow were collected to evaluate the effect of the treatment on ticḱs reproduction (in vitro assays). The pure form of TTO caused a significant reduction (P<0.05) in the number of ticks from the Group B compared to the Group A on day 4 PT. However, there was no significant difference in the number of ticks on cows from Groups A and C after treatment (P>0.05). Treatment with TTO in nanocapsules (Group C) interfered with R. microplus reproduction, leading to lower oviposition by female ticks and hatchability (34.5% of efficacy). On the other hand, TTO oil (Group B) did not interfere on ticḱs reproduction, i.e. showed higher hatchability than the control group. Therefore, it is possible to conclude that pure TTO has an acaricidal effect in dairy cows, in addition to an effect on ticḱs reproduction when used its nanocapsulated form.

Metaphylactic effect of minerals on immunological and antioxidant responses, weight gain and minimization of coccidiosis of newborn lambs

The aim of this study was to evaluate the metaphylactic effect of minerals on immunological and antioxidant responses, as well as performance and prevention of coccidiosis in newborn lambs. We divided 110 newborn lambs into two groups (55/group): control (untreated) and treated with two doses of 0.33 mL/kg of a mineral complex (zinc, copper, selenium, and manganese) on day of life (DOL) 1 and 30. Total blood was collected at DOL 1, 15, 30 and 45 to measure antioxidant enzymes, biochemical and immunology analyses, and haemogram. Treated animals were heavier (P < .05) than untreated lambs on DOL 15 and 45, but not on DOL 30 due to a coccidiosis outbreak. Catalase activity did not differ between groups, while superoxide dismutase and xanthine oxidase activities were higher (P < .05) in treated lambs compared with control animals. Serum levels of total protein and globulins were higher (P < .05) in treated animals (DOL 15, 30 and 45). A significant increased on the number of lymphocytes (DOL 45), as well as on seric levels of immunoglobulins (IgM and IgG) was observed in treated animals (DOL 15 and 30). Serum Ig levels remained constant throughout the experiment in the treated group, but fluctuated in the control group. Serum glucose levels were greater in treated animals (DOL 15 and 30). It is possible to conclude that subcutaneous administration of minerals has beneficial effects on lambs by increasing antioxidant and immunological defenses, reflected by greater weight gain, which could mitigate the impact of coccidiosis.