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Os nematóides gastrintestinais são responsáveis por acentuada redução na produtividade de ovinos e caprinos. Na tentativa de controlar esses parasitos, são utilizados diversos anti-helmínticos sintéticos, mas o desenvolvimento da resistência tem tornado esse controle pouco eficaz. Na busca por alternativas de controle dos nematóides gastrintestinais, a utilização de plantas taniníferas tem despertado interesse de pesquisadores em várias regiões do mundo. Essa revisão visa a abordar os diversos aspectos relacionados ao fornecimento dessas plantas a ovinos e caprinos, bem como os principais resultados obtidos em pesquisas utilizando taninos para o controle de nematóides de pequenos ruminantes.

Tanniferous plants represent a promising alternative for controlling gastrointestinal nematodes of small ruminants. This experiment evaluated the effects of extracts from the leaf and stem of Anadenanthera colubrina, Leucaena leucocephala and Mimosa tenuiflora on larval exsheathment of Haemonchus contortus in vitro and verified the role of tannins in this process. Third-stage larvae of H. contortus were incubated with extracts for 3 hours and were exposed to sodium hypochlorite solution. The extracts were tested at 300 µg.mL-1 and accompanied by controls: phosphate buffer solution (PBS) and polyvinyl polypyrrolidone (PVPP). The larval exsheathment was evaluated for 60 minutes, and the results were subjected to the Kruskal-Wallis test (p < 0.05). The six extracts blocked larval exsheathment. After PVPP addition, a tannin inhibitor, the exsheathment percentage was similar to the PBS (p > 0.05), except for L. leucocephala and M. tenuiflora leaf extracts. However, pre-incubation with PVPP of these two extracts significantly changed larval exsheathment when compared to the non-treated extracts (p < 0.05). These results suggest that A. colubrina, L. leucocephala and M. tenuiflora could be useful in gastrointestinal nematode control and that tannins are probably the main compounds involved in the observed effects. However, in vivo and toxicological studies should be conducted. Plantas taniníferas representam uma promissora alternativa de controle dos nematóides gastrintestinais de pequenos ruminantes. Esse experimento avaliou in vitro os efeitos dos extratos das folhas e caules de Anadenanthera colubrina, Leucaena leucocephala e Mimosa tenuiflora sobre o desembainhamento larvar de Haemonchus contortus e verificou o papel dos taninos nesse processo. Larvas de terceiro estádio de H. contortus foram incubadas com 300 µg.mL-1 de extrato por 3 horas e expostas a uma solução de hipoclorito de sódio. O ensaio foi acompanhado por controles: solução salina tamponada com fosfato (PBS) e polivinilpolipirrolidona (PVPP). O desembainhamento larvar foi avaliado durante 60 minutos e os resultados submetidos ao teste Kruskal-Wallis (p < 0,05). Os seis extratos bloquearam o desembainhamento larvar. Após adição de PVPP, um inibidor de taninos, o percentual de desembainhamento foi similar ao PBS (p > 0,05), exceto nos extratos das folhas de L. leucocephala e M. tenuiflora. Entretanto, a pré-incubação desses dois extratos com PVPP alterou significativamente o desembainhamento quando comparado com extratos não-tratados (p < 0,05). Esses resultados sugerem que A. colubrina, L. leucocephala e M. tenuiflora podem ser úteis no controle de nematóides gastrintestinais e que os taninos são provavelmente os principais compostos envolvidos nos efeitos. Contudo, estudos toxicológicos e in vivo são necessários.

The objective of this work was to evaluate ovicidal and larvicidal effects of Eucalyptus globulus essential oil (EGEO) on Haemonchus contortus. The chemical composition determination of EGEO was through gas chromatography and mass spectrometry. Egg hatch test (EHT) was performed in concentrations 21.75; 17.4; 8.7; 5.43 e 2.71 mg x mL(-1). In larval development test (LDT) were used the concentrations 43.5; 21.75; 10.87; 5.43 e 2.71 mg x mL(-1). Each trial was conducted by negative control with Tween 80 (3%) and positive control, 0.02 mg x mL(-1) of thiabendazole in EHT and 0.008 mg x mL(-1) of ivermectin in LDT. The maximum effectiveness of EGEO on eggs was 99.3% in concentration of 21.75 mg x mL(-1) and on larvae was 98.7% in concentration 43.5 mg x mL(-1). The concentration of EGEO that inhibits 50% of the eggs and larvae was 8.3 and 6.92 mg x mL(-1), respectively. The oil chemical analysis identified as main component the monoterpen 1,8-cineol. EGEO presented ovicidal and larvicidal activities in vitro, revealing a good potential for use in the control of sheep and goat gastrointestinal nematodes.