Abstract Abstract: This study evaluated the effect of oregano essential oil added to the feed of commercial laying hens. This research was focused on the analysis of biochemical changes linked to hepatic function, and protein and lipid metabolism. It was used 240 laying hens (59 weeks-old) distributed in a completely randomized design of six treatments (five repetitions with eight birds each). The experiments were constituted by a control treatment (CT) with the inclusion of zinc bacitracin and five treatments of oregano essential oil (OEO: 0, 50, 100, 150, and 200 mg.kg-1), respectively. After 28 days of feeding, an increase on serum levels of total proteins and globulins was observed on groups T150 and T200, as well as an increase on albumin levels on group CT. After 84 days of feeding, a significant reduction on total proteins and albumin was observed on group T200, as well as an increase in serum triglycerides. OEO at 200 mg.kg-1 increased globulin levels on day 28, which may be considered an effect in the inflammatory response, which increases serum immunoglobulins and proteins.

A resistência de anti-helmínticos em pequenos ruminantes é um problema comum e de interesse em todo o mundo. O objetivo deste estudo foi verificar a eficácia do tratamento anti-helmíntico em ovinos naturalmente infectados. Este estudo foi realizado em nove rebanhos que utilizaram o mesmo anti-helmíntico por mais de um ano. Em cada fazenda, os animais foram divididos em dois grupos: grupo controle, não tratado (n = 5) e tratados (n = 10) com base no número de ovos por grama nas fezes (OPG). O efeito do tratamento foi avaliado com base nos resultados de OPG e coprocultura realizados antes do tratamento e 10 dias após. Não foi observada diferença significativa (P > 0,05) entre os grupos tratados e não tratados em relação aos resultados do OPG. A coprocultura demonstrou que os animais estavam infectados principalmente porHaemonchus spp., Trichostrongylus spp.,Teladorsagia spp., Cooperia spp. eOesophagostomum spp. Em todas as fazendas foi encontrada resistência anti-helmíntica dos helmintos Haemonchusspp. e Trichostrongylus spp., mas esta resistência variou muito entre fazendas. Haemonchus spp. demonstrou ser resistente ao closantel, levamisol e albendazol. Trichostrongylus spp. demonstrou ser resistente ao levamisole, closantel e albendazol. As drogas testadas mostraram-se eficientes contra Teladorsagia spp.,Cooperia spp. e Oesophagostomum spp. Com base nesses resultados, podemos concluir que a resistência anti-helmíntica às drogas testadas é um problema presente nas fazendas avaliadas.

The anthelmintic resistance in small ruminants is a common problem and concern worldwide. The aim of this study was to verify anthelmintic treatment efficacy in naturally infected sheep. This study was conducted on nine herds that used the same anthelmintic management for over a year. In each farm, the animals were divided into two groups: untreated control group (n = 5) and treated (n = 10) according to the number of eggs per gram of feces (EPG). The treatment effect was checked based on EPG results and larval culture performed before treatment and 10 days after treatment. Significant differences were not observed (P> 0.05) on EPG results between untreated and treated groups. The coproculture showed that the animals were infected primarily byHaemonchus spp., Trichostrongylus spp.,Teladorsagia spp., Cooperia spp. andOesophagostomum spp. In all farms, anthelmintic resistance by genera Haemonchus and Trichostrongylus was found, but this resistance varied greatly between farms.Haemonchus spp. showed resistance to closantel, levamisole, and albendazole. Trichostrongylus spp. was shown to be resistant to closantel, levamisole, and albendazole. The drugs tested showed to be efficient against the genera Teladorsagia,Cooperia, and Oesophagostomum. Based on these results, we conclude that the anthelmintic resistance to the tested drugs is a problem present in the farms evaluated.