Herbal products such as essential oils may play a promising role in the treatment of infections caused by gastrointestinal nematodes (GINs). The aim of this study was to evaluate the in vitro potential of 11 essential oils (EOs) and one binary combination of isolated EO compounds, as well as the in vivo anthelmintic efficacy of two EO formulations. Four GIN genera were identified in the coproculture examination: Haemonchus, Trichostrongylus, Teladorsagia and Chabertia. The in vitro egg hatch test (EHT) was performed at six different concentrations (50, 12.5, 3.125, 0.781, 0.195 and 0.049 mg/mL) for each EO, whereas in the in vivo faecal egg count reduction test (FECRT), each EO sample was diluted in sunflower oil and orally administrated at a dose of 100 mg/kg to the different group of animals. In the EHT, the EOs of Origanum vulgare, Foeniculum vulgare, Satureja montana, Satureja hortensis and two types of Thymus vulgaris were the most effective. The dominant compounds of these EOs were carvacrol, thymol, anethol, p-cymene and γ-terpinene, indicating their importance for the anthelmintic activity. In the FECRT, both T. vulgaris EO type 1 and linalool:estragole combination show an anthelmintic potential with a mean effect on FECR of approximately 25%. The results suggest the possible role of tested EOs as anthelmintic agents in sheep farms, although further in vivo tests are needed.

The development of anthelmintic resistance in sheep gastrointestinal nematodes (GINs) requires novel strategies for the sustainable control of these parasites. This study aimed to evaluate the anthelmintic efficacy of the Origanum vulgare (L.) essential oil (EO) against sheep GINs and to evaluate the possibility of its use in control practice. The in vitro egg hatch test was conducted at eight different concentrations (50, 12.5, 3.125, 0.781, 0.195, 0.049, 0.025, and 0.0125 mg/mL) of the tested EO. For the in vivo fecal egg count reduction test, the EO of O. vulgare was administrated orally at a mean single dose of 150 mg/kg to sheep from two farms in Southern Italy, whereby potential toxic effects to the hosts were also evaluated. In the egg hatch test, the inhibition of egg hatchability varied from 71.3% to 93.7%, depending on the concentration used. The high anthelmintic potential was confirmed in the fecal egg count reduction test with an average reduction of nematode eggs in feces of 43.2% and 60.1% on days 7 and 14 after treatment, respectively. In addition, no toxic effects were noticed during the clinical examination of sheep or by observing blood count and liver or kidney function test results. The obtained results suggest the strong activity of the O. vulgare EO against sheep GINs, probably due to a high percentage of carvacrol (76.21%), whereby it can be considered safe for sheep at the dose tested in vivo. Therefore, it is suitable for use in veterinary practice as a part of an integrated strategy for the control of sheep GINs.

Nowadays, the exclusive use of commercial anthelmintics for the treatment of gastrointestinal nematode infections in ruminants is less sustainable due to anthelmintic resistance, as well as the problem of drug residues in animal products and the environment. Therefore, an integrated therapeutic approach is needed, including the search for alternatives to synthetic anthelmintic drugs. The aim of this study was to evaluate the possibility of using the essential oil of peppermint (Mentha x piperita L.) in the control of gastrointestinal nematodes in sheep. For this purpose, the in vitro and in vivo anthelmintic efficacy of this oil and the toxic effects on the hosts were examined. In the in vitro egg hatch test, ovicidal activity varied from 21.0–90.3% depending on the concentration of essential oil used (0.0125, 0.025, 0.049, 0.195, 0.781, 3.125, 12.5, and 50 mg/mL). To some extent, anthelmintic efficacy was confirmed in the in vivo fecal egg count reduction test at a mean dose of 150 mg/kg, with an average reduction of nematode eggs of 26.9 and 46.0% at Days 7 and 14 after treatment, respectively. Furthermore, no toxic effects of applied oil were observed on sheep behavior, kidney, or liver function. The main compounds identified by gas chromatography–mass spectrometry analyzes were menthol (32.6%), menthone (22.0%), menthyl-acetate (10.0%), and isomenthone (9.39%). Due to their complex chemical compositions, numerous bioactive ingredients, and natural origin, herbal formulations represent a potentially valuable alternative for the control of gastrointestinal nematodes in sheep. In this context, the results of the present study showed that peppermint essential oil is one of the promising candidates. Further studies should be performed to collect more data on the safety profile of M. piperita EO in treated animals to find the most appropriate formulation for use in field conditions and to test it against resistant gastrointestinal nematode populations.

Previous experimental models on cows have examined the difference in the metabolic adaptation in cows after niacin administration, without identifying the most important mediators between niacin administration and its biological effects, namely active forms of niacin. All tissues in the body convert absorbed niacin into its main metabolically active form, the coenzyme nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). The aim of this study was to determine the influence of niacin administration in periparturient period on NAD, NADP and the NAD:NADP ratio and to determine relationship between these indicators of an active form of niacin with metabolic parameters in cow blood. The study included 90 healthy cows: 45 cows receiving niacin and 45 cows were negative control. The niacin group was treated with nicotinic acid for two weeks before, as well as two weeks after parturition. Nicotinic acid was applied per os with feed. In cows receiving niacin, there was a significantly higher concentration of NAD and NADP, but the NAD:NADP ratio did not differ compared with control. All three indicators were able to separate cows who received and who did not receive additional niacin. NAD and NADP are good indicators of the availability of niacin from additional sources. The NAD:NADP ratio is a good indicator of the biological effect of applied niacin on metabolites in cows due to its correlation with a number of metabolites: positive correlation with glucose, insulin, glucose to insulin ratio and the revised quantitative insulin sensitivity check index (RQUICKIBHB) of insulin resistance, triglycerides and cholesterol, and a negative correlation with nonesterified fatty acid (NEFA), beta hydroxybutyrate (BHB), gamma-glutamyltranspherase (GGT) and urea in cows receiving niacin. The same amount of added niacin in feed can produce different concentrations of NAD, NADP and NAD:NADP in the blood, and this was not related to their concentration before the addition of niacin. The change in the concentration of the active form of niacin (NAD, NADP and NAD:NADP) further correlates with the concentration of metabolic parameters, which indicates that the intensity of the biological effect of additional niacin can be accurately determined only if we know the concentrations of its active forms in blood. Under basal conditions (without additional niacin), active forms of niacin that already exist in the blood do not show significant correlations with metabolic parameters.

Background: The increasing difficulties in combating anthelmintic resistance in gastrointestinal nematodes (GINs) of sheep worldwide, and the residues of chemical drugs in animal products and the environment, necessitate the search for alternatives. Previous studies have shown that plant essential oils (EOs) could be valuable anthelmintic agents, due to their numerous advantages. The present study aimed to evaluate the possibility of using winter savory (Satureja montana L.) EO against sheep GINs. The chemical composition of the tested oil was determined by gas chromatography-mass spectrometry (GC–MS). The efficacy of the tested oil was determined in vitro using the egg hatch test (EHT), and in vivo using the faecal egg count reduction test (FECRT) performed in two farms. Preliminary toxicity studies including clinical observation, haematological and biochemical blood analysis were also performed to evaluate the safety of the tested oil to the hosts. In addition, a coproculture study was carried out in the tested farms using the appropriate morphological keys. Results: Main compounds of the S. montana oil identified by GC–MS analysis were p-cymene (42.8%), carvacrol (28.1%) and y-terpinene (14.6%). The in vitro EHT showed a dose-dependent (R² = 0.94) anthelmintic potential of the tested oil, with ovicidal activity varying from 17.0–83.3% and determined IC₅₀ value of 0.59 mg/ml. The field efficacy reached 33% (at group level) and 50% (at individual level) at D14 after treatment. In vivo efficacy was significantly higher in farm 2 (FEC above 65% at group level, p < 0.05) where sheep were kept in pens during treatment. No toxic effects were observed, either in the physical observation of the test animals or in their liver and kidney function. No significant changes (p > 0.05) in the percentage representation of GIN genera were observed in the coproculture study, indicating that the treatment agent was not specific to a single genus. Conclusion: The anthelmintic potential showed on EHT and FECRT, without adverse effects on the sheep, suggests that S. montana EO is suitable for the control of sheep GINs as part of an integrated parasite management. However, further studies should be conducted to increase efficacy in field conditions.

Essential oils have numerous medicinal properties which include antiseptic, antiinflammatory, anticancer but also antiviral, antimicrobial and antiparasitic effects. Although researches have highlighted different possible application of these oils, little is known about their use in animals including dogs and cats. Specifically, essential oils showed effects against various bacterial (Staphylococcus spp., Pseudomonas aeruginosa, Enterococcus spp.), fungal (Malassezia pachydermatis, Microsporum canis, Trichophyton mentagrophytes), endoparasitic (Giardia duodenalis, Echinococcus granulosus, Toxocara canis) and ectoparasitic (Otodectes cynotis, Demodex canis, Ctenocephalides felis, some ticks etc) pathogens in dogs and cats. In addition, essential oils exhibit numerous positive properties such as complex chemical composition (high efficacy, less susceptibility to resistance), their natural origin etc. Therefore, certain essential oils based formulations are already in use, such as different shampoos. However, the main limitation for the use of these plant products is the insufficiently tested safety of use. Thus, some essential oils are considered toxic to pets, especially when used on cats. The main reason for this is most likely the deficiency of some liver enzymes that are involved in metabolic processes (as UDP-glucuronosyltransferase in cats), which leads to the accumulation of some active ingredients in the organism and their toxicity. Therefore, caution and rational application are needed in terms of adequate selection of plant species, dosage, concentration and the methods of use. In addition, since essential oils are prone to evaporation and instability, the encapsulation technique can further increase their in vivo efficacy as well as enable controlled release. That can reduce the required dose and additionally increase safety of their application.