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Title: Evaluation of Cymbopogon schoenanthus essential oil in lambs experimentally infected with Haemonchus contortus

Author
item KATIKI, LUCIANA - Universidad De Sao Paulo
item CHAGAS, ANA CAROLINA - Embrapa
item TAKAHIRA, R - Sao Paulo State University (UNESP)
item JULIANA, H - Rutgers University
item Ferreira, Jorge
item AMARANTE, ALESSANDRO - Sao Paulo State University (UNESP)

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2011
Publication Date: 4/20/2012
Citation: Katiki, L., Chagas, A., Takahira, R.K., Juliana, H.R., Ferreira, J.F., Amarante, A. 2012. Evaluation of Cymbopogon schoenanthus essential oil in lambs experimentally infected with Haemonchus contortus. Veterinary Parasitology. 186:312-318.

Interpretive Summary: Blood-feeding gastrointestinal worms cause significant economic losses in small ruminant grazing systems. The growing reports of multi-drug resistant worms call for intensive research on alternative treatments for anthelmintics to help small ruminants cope with these parasites. Two-month-old lambs with mean body weight (BW) of 22.5 kg were experimentally infected with a multidrug-resistant strain of the barberpole worm, which is the most serious parasite in small ruminant grazing systems. Infected animals were orally dosed with lemon grass essential oil to evaluate its anthelmintic potential. Eighteen animals were allocated into three groups of six animals each that received one of the following treatments: Group 1 – control, received 10 mL of water, Group 2 – lemon grass essential oil (180 mg/kg BW); and Group 3 – lemon grass essential oil (360 mg/kg BW). Animals received the oil once a day for three consecutive days. Lambs were monitored for parasite fecal output and for changes in blood biochemistry during the experiment (before, at 1, 5, 10, 15 and 20 days after treatment). Lambs were then euthanized to evaluate the total worm burden. No statistically-significant reduction in fecal egg output, red blood cell volume or total worm count was observed after treatments. Also, no statistical difference among group means for blood levels of urea, creatinine, albumin, alkaline phosphatase, aspartate aminotransferase and gamma glutamyl transferase was found. Worm larval development assay (LDA) and egg hatch assay (EHA) was performed using feces from infected animals 1,5,10 and 15 days after essential oil administration and a slight inhibition in LDA was observed in feces from animals that received 360 mg/kg essential oil one day after treatment. Blood biochemistry demonstrated that there were no clinical signs of toxicity of the essential oil used in this study and that no anthelmintic effect against the barberpole worm was observed in treated animals other than a small inhibition of worm larval development from feces of treated animals. These findings indicate that although lemon grass oil had no effect on the worm in the host, there is some potential to break the life cycle of the parasite in the feces, reducing pasture infestation.

Technical Abstract: Hematophagous gastrointestinal parasites cause significant economic losses in small ruminant grazing systems. The growing reports of multi-drug resistant parasites call for intensive research on alternative treatments for anthelmintics to help small ruminants cope with these parasites. Two-month-old lambs with mean body weight (BW) of 22.5 kg were experimentally infected with a multidrug-resistant Haemonchus contortus strain. Infected animals were dosed orally with Cymbopogon schoenanthus essential oil to evaluate its anthelmintic potential. Eighteen animals were allocated into three groups of six animals each that received one of the following treatments: Group 1 - control, received 10 mL of water, Group 2 - C. schoenanthus essential oil (180 mg/kg BW); and Group 3 - C. schoenanthus essential oil (360 mg/kg BW). Animals received the oil once a day for three consecutive days. Lambs were evaluated clinically for blood biochemistry before, at 5, 10 and 20 days after treatment, and then were euthanized to assess the total worm burden. No statistically-significant reduction in fecal egg count, packed cell volume or total worm count was observed after treatments. Also, no statistical difference among group means for blood levels of urea, creatinine, albumin, alkaline phosphatase, aspartate aminotransferase and gamma glutamyl transferase was found. Larval development assay (LDA) and egg hatch assay (EHA) was performed using feces from animals after 1,5,10 and 15 days after essential oil administration with a slight inhibition in LDA being observed in feces from animals that received 360 mg/kg essential oil one day after the three-day treatment.