Ovicidal, larvicidal and adulticidal activity of black pepper (Piper nigrum L.) essential oil and tea tree oil (Melaleuca alternifolia) against Haemonchus contortus.

Haemonchosis is a worldwide helminthic disease affecting ruminants. The anthelminthic resistance has become raised. Medicinal plants are safely used as synthetic anthelmintics. Currently, the efficacy of black pepper essential oil (BPO) and tea tree oil (TTO) were in vitro evaluated against Haemonchus contortus adults, eggs and larvae at concentrations of 1.25, 2.5 and 5 mg/ml in addition to the commercially used albendazole at a concentration of 10 µg/ml. Oils were used in both normal and nanoparticles-loaded forms. Oxidative stress enzymes of worms were estimated. Scanning electron microscopy (SEM) for treated worms was done. Both normal and nanoemulsion forms of both BPO and TTO stopped the adult motility [BPO 2.5 h (hrs), NBPO 1.5 h, TTO 3 h, NTTO 1.5 h] and induced a marked decrease in the oviposition. Post treatment, the egg development and hatching were significantly (P ≤ 0.05) reduced. The damage of the egg shell, embryonal cessation and destruction of larvae occurred. Noticeable elevated antioxidant enzymes (catalase CAT, glutathione transferase GST and glutathione GSH) were found, while oxidative enzymes (lipid peroxidation LPO and nitric oxide synthase NOS) decreased. Scanning electron microscopy (SEM) for both oil-treated worms revealed anterior ends damage and several cuts associated with cuticular pores. The use of albendazole induced more or less anthelmintic and enzymatic activities with less morphological alterations of adults revealed by SEM. This study proved the marked anthelmintic potency of the BPO and TTO and their nanoemulsion forms against H. contortus rather than the widely used anthelmintic drugs.

Control of Rhipicephalus annulatus resistant to deltamethrin by spraying infested cattle with synergistic eucalyptus essential oil-thymol-deltamethrin combination.

The current study investigated the synergistic effect of combinations containing deltamethrin (D), Eucalyptus essential oil (E), and the thyme essential oil component thymol (T), against a field population of Rhipicephalus annulatus in Egypt that was characterized to be resistant to D. Solutions of T, E, or TE at concentrations of 1.25-5% were combined with 5% deltamethrin at different dilutions (0.25-2 mL/L). Results of the adult immersion test used to estimate the in vitro acaricidal activity of these combinations at 5% yielded LC50 values for D, E-D, T-D, and TE-D of 3.87 mL/L, 3.89 mL/L, 0.14 mL/L, and 0.05 mL/L, respectively. Biochemical analyses using whole-body homogenate of ticks from the in vitro tests revealed that the lowest acetylcholinesterase and glutathione peroxidase activity, and the maximum lipid peroxidation were recorded in ticks treated with 5% TE-D. Glutathione content significantly decreased (p ≤ 0.05) in all treated ticks. Three groups, each containing five cross breed cattle naturally infested with R. annulatus from the same area where resistance to D was detected, were sprayed twice at two-week intervals using 1 mL/L of 5% solutions of D, T-D, or TE-D. Overall efficacy of the D, T-D, and TE-D sprays by day 30 post-treatment was 21.6, 88.3, and 95 %, respectively. Ticks collected from infested cattle three days after treatment with the D spray deposited egg masses that were able to hatch, deposited small masses of eggs unable to hatch when exposed to the T-D spray, and laid few eggs that didn't hatch when sprayed with the TE-D combination. Values for liver and kidney function parameters were comparable in cattle before and after treatment with the combination sprays tested. The TE-D spray overcame the insensitivity to D of this R. annulatus population in Egypt, which also highlighted the significant synergistic effect of thymol on the acaricidal activity of deltamethrin observed in vitro. Acaricidal activity of the TE-D combination apparently has deleterious effects on multiple tick systems involving inhibition of acetylcholinesterase, increased lipid peroxidation, and oxidative stress. These findings document that combinations of natural and synthetic products can be part of integrated management solutions to the problem with widespread resistance to pyrethroids like deltamethrin in populations of cattle ticks, including R. annulatus, around the world.

Thymol efficacy against coccidiosis in pigeon (Columba livia domestica).

Investigation of thymol efficacy to control pigeon coccidiosis was performed using in-vitro and in-vivo studies. The in-vitro experiment was conducted by treatment of unsporulated oocysts of Eimeria species of pigeon by five concentrations (0.625-10%) from either thymol, eucalyptus essential oil or amprolium anticoccidial drug and incubation for 72 h. The in-vitro study revealed that thymol concentrations ≥1.25 % caused significant deformity on sporulated and unsporulated oocysts compared to the other two products. Eucalyptus oil was active at both 5 and 10 % concentrations on unsporulated oocysts but showed non-significant changes on sporulated ones at all tested concentration. Meanwhile, in-vivo testing of thymol was conducted using 45 squabs which were equally divided into three groups; untreated uninfected (UU) negative control, untreated infected (UI) positive control and thymol treated (TT). TT group received 40 mg/kg BWt thymol in feed for 15 days. At day five post thymol supplementation, the UI and TT groups were orally infected by 25 × 103sporulated oocysts of pigeon Eimeria labbeana. The in-vivo study showed that thymol minimized the adverse effect of Eimeria infection in pigeon as observed by less severity of clinical signs, low oocysts count and improvement of body weight when compared with untreated infected birds. In addition, the biochemical parameters including liver and kidney functions tests proved thymol safety in pigeon. Moreover, thymol showed excellent antioxidant activity that was estimated by significantly lower value of malondialdehyde in TT than UI groups. The histopathological findings of TT group showed intact intestinal villi with mild sloughed epithelium, degenerated coccidian developmental stages and massive infiltrations of mononuclear cells in lamina propria. In conclusion, thymol can be safely used to control pigeon coccidiosis as a natural effective compound.

In vitro activity of natural and chemical products on sporulation of Eimeria species oocysts of chickens.

This study was designed to investigate the ability of two herbal extracts and different chemical substances to inhibit or disrupt sporulation of Eimeria species oocysts of the chickens. The two herbal extracts were Allium sativum (garlic) and Moringa olifiera while the chemical substances included commercial disinfectants and diclazuril. Field isolates of Eimeria oocysts were propagated in chickens to obtain a continuous source of oocysts. The collected unsporulated oocysts (105oocysts/5 ml) were dispensed into 5 cm Petri dish. Three replicates were used for each treatment. The treated oocysts were incubated for 48 h at 25-29 °C and 80% relative humidity. The results showed that herbal extracts, the commercial recommended dose of Dettol, TH4, Phenol, Virkon®S, and Diclazuril 20% have no effect on the sporulation. While Sodium hypochlorite showed a significant degree of sporulation inhibition reached to 49.67%. Moreover, 70% ethanol, and 10% formalin showed 100% sporulation inhibition. It was concluded that 70% ethanol and 10% formalin are the most effective methods to inhibit Eimeria species sporulation.