Carvacrol is an essential oil derived from oregano that is used as a natural additive to improve the efficiency of livestock nutrition. Residues of natural additives such as carvacrol should be monitored in food of animal origin to ensure consumer safety. The aim of this study was to appraise the quick, easy, cheap, effective, rugged and safe (QuEChERS) approach coupled with liquid chromatography and mass spectrometry as a means of carvacrol analysis in chicken tissue.

Carvacrol is an essential oil extracted from oregano which can be used as a natural additive in poultry litter and could have a positive impact not only on production rates but also on the quality of poultry meat. The aim of this study was to evaluate the effect of the addition of carvacrol to litter on weight gain and the occurrence of residues in chicken tissues.

In this study we examined the anti-tick properties of the essential oil of Tagetes minuta L. (Asteraceae: Asterales) against Hyalomma rufipes ticks. We obtained the essential oil of T. minuta by hydro-distillation of a combination of fresh flowers, leaves and soft stems, and analysed these by using gas chromatography (GC) and gas chromatography-linked mass spectrometry (GC-MS). The oil had a high percentage of monoterpenes and the major compounds identified were cis-ocimene (28.5%), beta-ocimene (16.83%) and 3-methyl-2-(2-methyl-2-butenyl)-furan (11.94%). Hyalomma rufipes adults displayed a significant (P < 0.05) dose repellent response to the essential oil of T. minuta. Probit analysis indicated a repellent EC50 of T. minuta essential oil for male ticks to be 0.072 mL/mL (CI 0.053 mL/mL to 0.086 mL/mL) and 0.070 mL/mL (CI 0.052 mL/mL to 0.084 mL/mL) for female ticks. There were no significant differences in repellent responses between male and female ticks. The oil also significantly (P < 0.05) delayed moulting of 60% of H. rufipes engorged nymphs. These results suggest that T. minuta may be a potential source of anti-tick agents.

Carvacrol is an essential oil derived from oregano that is used as a natural additive to improve the efficiency of livestock nutrition. Residues of natural additives such as carvacrol should be monitored in food of animal origin to ensure consumer safety. The aim of this study was to appraise the quick, easy, cheap, effective, rugged and safe (QuEChERS) approach coupled with liquid chromatography and mass spectrometry as a means of carvacrol analysis in chicken tissue. A 5 ± 0.05 g portion of plasma, lung, muscle and liver was mixed for 15 min with 5 mL of 1-butanol and 20 mL of water, then centrifuged. A 0.5 mL volume from the top layer was transferred, then 60 mg of octadecylsilane sorbent, 30 mg of primary and secondary amine and 200 mg of MgSO₄ were added. The extract was mixed and centrifuged. The top layer was filtered and then transferred to an autosampler vial for analysis by high-performance liquid chromatography–tandem mass spectrometry. The limit of detection was calculated at 0.06 μg g⁻¹ and the limit of quantification was 0.2 μg g⁻¹, with relative standard deviation repeatability and reproducibility below <20%. The validation results showed that this method could be a good alternative to determination of carvacrol by gas chromatography and is suitable for carvacrol analysis in different matrices.

Bovine mastitis is an inflammatory disease of the udder that causes important economic losses in the animal breeding and dairy product industries. Nowadays, the conventional livestock antibiotic treatments are slowly being replaced by alternative treatments. In this context, the main aim of this study was to evaluate the efficacy of natural products in alternative treatment of bovine mastitis. Two natural formulations with previously suggested in vitro antimicrobial effect were tested in vivo on mastitic cows. Animals with a positive diagnosis for mastitis (n = 20) were divided into three treatment groups: two groups (n = 8) were administered formulations of propolis, alcoholic extracts of Brewers Gold and Perle hops, plum lichen, common mallow, marigold, absinthe wormwood, black poplar buds, lemon balm, and essential oils of oregano, lavender, and rosemary designated R4 and R7 (differing only in the latter being more concentrated) and one group (n = 4) a conventional antibiotic mixture. In vivo efficacy of treatments was evaluated by somatic cell and standard plate counts, the treatment being considered efficacious when both parameters were under the maximum limit. R7 was effective in the most cases, being therapeutically bactericidal in six out of eight cows, while R4 gave good results in three out of eight cows, and conventional antibiotics cured one out of four. These results suggest the possible therapeutic potential of these natural products in bovine mastitis.

Emergence of antibiotic resistant bacteria has created the necessity of replacement of antibiotic with other products like prebiotics, probiotics, organic acid botanicals, and herbal essential oils. Essential oils (EOs) are important aromatic components of herbs and spices, and are used as natural alternatives for replacing antibiotic growth promoters (AGPs) in poultry feed as these have antimicrobial, antifungal, antiparasitic, and antiviral properties. Beside, other beneficial effects of EOs include appetite stimulation, improvement of enzyme secretion related to food digestion, and immune response activation. Recently, use of EOs in broiler chickens has drawn attentions. EOs are generally used as blend with a carrier oil or combination with other plant oils in the feed to enhance the productive performance of birds. Conclusively, EOs can be used in poultry feed, but there are still questions concerning their action, metabolic pathway and optimal dosage in poultry, which are to be explored in detail. This mini-review describes the expanding horizons in the research on EOs in poultry nutrition.

Emergence of antimicrobial resistance (AMR) among fish bacterial pathogens is one of the major global public threats. Attempts are being made to develop novel alternatives as a promising approach to combat multidrug resistance disease-causing bacteria. Natural antimicrobials such as essential oils (EOs) are a potential unique strategy to treat bacterial infections with a reduced risk of resistance developing. This study aimed to evaluate the antimicrobial activity of some essential oils (EOs) namely, cinnamon (Cinnamomum zeylanicum), clove (Syzygium aromaticum), Peppermint (Mentha piperita) , and black cumin (Nigella sativa) against some fish pathogens implicated with aquaculture disease outbreaks like Aeromonas hydrophilia, Pseudomonas fluorescence, Photobacterium damselae and Streptococcus agalactiae using agar well diffusion assay. We found significant differences on the antibacterial activity depending on the type of essential oils and bacterial strain. Among all the tested EOs, cinnamon essential oil (CEO) was shown to be the most effective with minimum bactericidal concentration (MBC) ranged from 0.0156-0.125 ml/ml. As a result, it was selected for our in vivo investigations. We next aimed to investigate the effects of dietary CEO on growth performance, disease resistance and immune response of fish. A total of 150 striped catfish (Pangasianodon hypophthalmus) were fed with different levels of CEO (0, 1.50, 2.0, 2.50, and 3.0 mL/kg diets) (assigned as control, Diet 1, Diet 2, Diet 3 and Diet 4) for 60 days. Compared to control, fish fed with graded levels of dietary CEO showed significant (P < 0.05) increase in final body weight, weight gain %, and specific growth rate particularly at fish group fed diet 3. Of interest, there were no significant differences (P > 0.05) in feed conversion ratio and survival rates among control and CEO-supplemented groups. Moreover, we found significant (P < 0.05) increases in plasma lysozyme activity and total IgM levels in a dose dependent manner with dietary CEO supplementation. After feeding trials, we investigated their potential to defend striped catfish against A. hydrophila challenge. Fish fed control diet had the highest mortality rates; in contrast, fish fed diets supplemented with CEO had higher levels of resistance to the bacterial infection, with the lowest mortality rates in the fish group fed diet 3. Overall, these findings showed that EOs exhibit a great potential to be used as antimicrobial agents against fish pathogens. Moreover, dietary administration of CEO, particularly at 2.5 ml/kg feed, can be regarded as a promising component for improving growth, immunological responses and potential alternatives to conventional antimicrobials for control of microbial infections in fish.

The current study was carried to investigate the prevalence of Campylobacter jejuni in broiler chicks in Dakhalia province. Besides, the effects of carvacol and thymol essential oils (EO), as a continuous drinking water treatment for protection against Campylobacter jejuni challenge in commercial broiler chickens were assessed. Four hundred and fifty samples were collected from 50 healthy bird, 100 freshly dead birds and 100 diseased birds. Out of 450 examined samples, 22.44 % (101̸450) were positive for Campylobacter jejuni. These isolates were sensitive for neomycin, amoxicillin and ceftriaxone. Random assignment of 180 one-day old chicks into 6 groups (30 birds/group in 3 replicates) arranged as follows: G1 as non-challenged group, G2 was challenged with C. jejuni while G3, and G4 were challenged with C. jejuni and continuously supplemented with carvacol and thymol, respectively, in drinking water from day 7. G5 was challenged with C. jejuni and had the two essential oils continuously in drinking water from day 7. G6 was challenged with Campylobacter jejuni and treated with neomycin (15 mg/kg B.W). Our results showed that the combination of essential oils was more effective in mitigating the devastating effects of Campylobacter jejuni challenge in broilers than using one EO alone. Growth performance represented by body weight gain, and feed conversion ratio were significantly (p<0.05) improved. Campylobacter jejuni shedding was reduced in the challenged treated groups. Also, the biochemical profile was improved. In addition, the level of the pro-inflammatory cytokines IL-1β and IL-6 were significantly down regulated in the challenged-treated group. In conclusion, it is highly recommended to use carvacol and thymol EO either alone or in a combination to improve the body performance and to protect broilers against Campylobacter jejuni.

Minced meat is a popular meat product found mainly in most types of meat meals as a source of animal-origin food. So, it has high economic worth due to its nutritive value. Owing to the high moisture content and richness in nitrogenous composites, it is an ideal medium for bacterial growth and contamination. Synthetic preservatives are used for extending the shelf life and enhancing quality properties of meat, but consumers are only recently considering them because of worries about potential health risks. Thus, using safe natural preservatives becomes an urgent necessity. The objective of the current study aimed to determine whether cranberry essential oil (CBEO) could improve the sensory, chemical, and microbial properties of raw minced beef while also extending its shelf life.60 minced beef samples were divided into 0.0 (control), 0. 5, 1, and 1.5% CBEO treated groups. The control and treated samples were kept at 3±1ºC in the refrigerator for 12 days. Minced beef samples’ sensory, chemical, and microbial properties were evaluated every three days. The results showed that CBEO addition significantly delayed the proliferation of aerobic plate counts, psychotrophic, Staphylococcal and Enterobacteriaceae bacterial counts and extended the shelf-life of the minced beef up to 12 days compared to the control group that was completely putrefied at the 6th day of storage. This study suggested that CBEO could be used as a natural preservative for chilled minced meat.

The importance of searching for natural alternatives away from chemicals in poultry health and treatment has benefits for humans in many directions, as we control the bad effect of the accumulation of harmful chemicals in their meat, as well as reduce the risk of zoonotic infection and preserve the environment from chemical pollution. Enormous fungi induce a considerable level of annihilation in the poultry industry and human consumers due to their zoonotic implications. This study is designed to explore the effects of keratogenic and toxigenic skin fungal affection and the effects of dietary-essential oils in broilers -chicken (n-120). Skin scrapings and feather samples were examined mycologically in association with PCR sequencing for genomes of the culturally detected fungi (in South Korea) based on phylum tree and all Sequences data was deposited in GenBank and each was assigned an accession number. Sera samples of the tested broilers were examined by ELIZA against biogenic amine mainly histamine during the summer season, also a histopathological examination of skin sections before and after taking feed additives (essential oils) as anti-fungal for thirty days, the broiler-fed diet was supplemented with peppermint, thyme, and Carvacrol 70 mg/kg (w/w) in dietary feed. The isolated fungi were: Fifteen fungal species belonging to 9 genera of filamentous fungi which were isolated from skin scrapings and feathers of chickens. Aspergillus niger and A. flavus are the most prevalent species (20 samples representing 100% of total samples for each. Rhizopus oryze 20% and Fusarium oxysporum 15% were cultured from total samples respectively. Four fungal species appeared in 10% of the tested samples which are Aspergillus qudrilineatus, Paecilomyces variotii (Byssochlamys spectabilis), Scopulariopsis brevicaulis and Exserohilum rostratum. Finally, the other seven fungi presented as 5% from tested samples. The average level of serum histamine before treatment was 16.6 ng/ml and after feeding was 12.3 ng/ml (significant decrease, P < 0.05) referring to the significant role of the essential oils in broilers ration.