Efficacy of free and nanoencapsulated Eucalyptus citriodora essential oils on sheep gastrointestinal nematodes and toxicity for mice

AbstractHerbal medicines with anthelmintic effects are alternatives for the sustainable control and prevention of disease caused by gastrointestinal parasites. The nanoencapsulation of essential oils has been proposed to enhance the absorption of their constituents and improve their efficacy. The present study aimed to evaluate the efficacy of free and nanoencapsulated Eucalyptus citriodora essential oil (EcEO) on the control of gastrointestinal nematodes of small ruminants in vitro and in vivo. Chitosan was used as a matrix for the formulation of a nanoemulsion. Chromatographic and physico-chemical analyses of EcEO were performed. Egg hatch (EHT) and larval development (LDT) tests were conducted to evaluate the effectiveness of nanoencapsulated and free EcEO on the eggs and larvae of Haemonchus contortus. Acute toxicity of free and nanoencapsulated EcEO was evaluated using mice. Finally, nanoencapsulated EcEO efficacy on the control of gastrointestinal nematodes was calculated by fecal egg count reduction test (FECRT) treating 30 sheep naturally infected with 250mg/kg of free and nanoencapsulated EcEO. In vitro tests were analyzed by an analysis of variance (ANOVA) followed by comparison with the Tukey test. The efficacy of FECRT was calculated by the BootStreet program through arithmetic average, using the formula 100 (1−XT/XC). To compare the differences between epg, the data were transformed to log(x+1) and subjected to an ANOVA to compare the significant differences between groups by Tukey's. The level of significance was P<0.05. The free (4mg/ml concentration) and nanoencapsulated (2mg/ml concentration) EcEO inhibited larvae hatching by 97.2% and 92.8%, respectively. Free and nanoencapsulated EcEO at 8mg/ml inhibited larval development by 99.8% and 98.1%, respectively. In the acute toxicity test, the LD10 and LD50 of free EcEO was 1999 and 2653mg/kg, respectively, while the LD10 and LD50 of nanoencapsulated EcEO was 1121 and 1681mg/kg, respectively. Nanoencapsulated and free EcEO reduced FEC similarly by 40.5% and 55.9%, respectively at 10 days post-treatment. Nanoencapsulated EcEO did not obtain the expected efficacy in vivo

Effects of Mimosa tenuiflora on larval establishment of Haemonchus contortus in sheep

AbstractAnthelmintic resistance has limited the ability to control the gastrointestinal nematodes of small ruminants and has therefore awakened an interest in the study of tanniferous plants as a source of anthelmintics. This study was carried out to evaluate the effect of Mimosa tenuiflora intake, a tanniferous plant that is fed to small ruminants in northeastern Brazil, on the larval establishment of Haemonchus contortus in sheep. In this experiment, 18 nematode-free sheep were divided into three groups (n=6) according to live weight. Group 1 was fed M. tenuiflora leaves; Group 2 was fed M. tenuiflora stems; Group 3 served as the control group and was fed Cynodon dactylon, a plant with low levels of tannins. The animals consumed the plants for 13 days (Day −7 to Day 5). On Day 0, the sheep were experimentally infected with 4500 third-stage H. contortus each. Five days after infection (Day 5), the sheep were slaughtered to count the worm burden and perform a histological analysis of the abomasum. The daily plant intake and the live weight gain of the animals were recorded. The groups that ingested M. tenuiflora leaves and stems consumed less dry matter than did those that ingested C. dactylon (P<0.05). The consumption of M. tenuiflora leaves did not reduce the L3 establishment of H. contortus compared to the control (P>0.05). The intake of M. tenuiflora stems tended toward decreasing larval establishment, but the reduction was not significant (P>0.05). No significant differences were observed in the mucosal cellular response and live weight gain among the groups. These data demonstrated that, with the protocol used, M. tenuiflora has no effect on larval establishment of H. contortus in sheep

Eficácia de plantas para o controle de nematóides gastrintestinais de pequenos ruminantes: revisão de estudos publicados Plant efficacy in small ruminant gastrointestinal nematode control: a review of published studies

As helmintoses gastrintestinais constituem um dos principais fatores limitantes para a ovinocaprinocultura em todo o mundo e a saúde dos rebanhos depende de um efetivo controle antiparasitário. A resistência aos anti-helmínticos representa um dos entraves para esse controle e a busca por novas bases tem sido um desafio constante. A utilização da fitoterapia na medicina veterinária constitui um campo promissor de pesquisas. Estudos nesta área necessitam da inserção em um contexto agroecológico, tendo como fator limitante o manejo sustentável dos recursos naturais envolvidos. O presente artigo apresenta uma revisão dos estudos de plantas cientificamente testadas no Brasil e em outros países para o controle das parasitoses gastrintestinais em pequenos ruminantes.<br>Gastrointestinal helminthiasis has been one of the main limiting factors to small ruminant breeding around the world and the health of these animals depends on an efficient parasitological control. Resistance to anthelmintics represents one of the barriers to this control and the search for new bases has been a constant challenge. The use of phytotherapy in Veterinary Medicine is a promising research field. Studies in this area require the insertion into an agroecological context, presenting as limitation the sustainable management of the involved natural resources. This paper presents a review of studies on plants scientifically tested in Brazil and other countries for gastrointestinal nematode control concerning small ruminants