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    Antimicrobial activity of essential oils and five terpenoid compounds against Campylobacter jejuni in pure and mixed culture experiments
    (Elsevier B.V., 2013) Kurekci, Cemil; Padmanabha, Jagadish; Bishop-Hurley, Sharon L.; Hassan, Errol; Al Jassim, Rafat A.M.; McSweeney, Christopher S.
    The aim of this study was to examine the antimicrobial potential of three essential oils (EOs: tea tree oil, lemon myrtle oil and Leptospermum oil), five terpenoid compounds (?-bisabolol, ?-terpinene, cineole, nerolidol and terpinen-4-ol) and polyphenol against two strains of Campylobacter jejuni (ACM 3393 and the poultry isolate C338), Campylobacter coli and other Gram negative and Gram positive bacteria. Different formulations of neem oil (Azadirachta indica) with these compounds were also tested for synergistic interaction against all organisms. Antimicrobial activity was determined by the use of disc diffusion and broth dilution assays. All EOs tested were found to have strong antimicrobial activity against Campylobacter spp. with inhibitory concentrations in the range 0.001-1% (v/v). Among the single compounds, terpinen-4-ol showed the highest activity against Campylobacter spp. and other reference strains. Based on the antimicrobial activity and potential commerciality of these agents, lemon myrtle oil, ?-tops (?-terpineol. +. cineole. +. terpinen-4-ol) and terpinen-4-ol were also evaluated using an in vitro fermentation technique to test antimicrobial activity towards C. jejuni in the microbiota from the chicken-caecum. EO compounds (terpinen-4-ol and ?-tops) were antimicrobial towards C. jejuni at high doses (0.05%) without altering the fermentation profile. EOs and terpenoid compounds can have strong anti. Campylobacter activity without adversely affecting the fermentation potential of the chicken-caeca microbiota. EOs and their active compounds may have the potential to control C. jejuni colonisation and abundance in poultry. © 2013 Elsevier B.V.
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    Effect of essential oil supplementation to diet on meat quality, fatty acid composition, performance parameters and intestinal microbiota of Japanese quails
    (Wiley, 2021) Kurekci, Cemil; Ozsoy, Bulent; Hassan, Errol; Ozkan, Huseyin; Gundogdu, Aycan; Ozsoy, Sule Yurdagul; Yakan, Akin
    The effect of essential oil (EO) supplementation on carcass characteristics of Japanese quails and interactions between ingredients and intestinal morphology were investigated in this study. A total of 250 quails were fed different diet: D1, basal diet (BD); D2, BD plus palmarosa oil (PO; 100 mu g/kg diet); D3, BD plus lemon myrtle oil (LMO; 100 mu g/kg diet); D4, BD plus alpha-Tops (mixture of alpha-terpineol, cineole and terpinene-4-ol; 100 mu g/kg diet); and D5, BD plus cyclodextrin. Overall growth performance was determined at multiple time points during 35 days of experiment. Carcass characteristics (fatty acid, pH and colour), intestinal morphology and the expression levels of meat quality-related genes including the insulin-like growth factor (IGF-1), myogenin and avian uncoupling protein (avUCP) were examined at the end of the trial. Additionally, intestinal microbiome of quails was studied by next-generation sequencing-based culture-independent analysis. Although the inclusion of EOs into the diet had no effect on the growth performance of quails and the microbial profile, the significant changes in pH(24)and colour (a*) of the quail's breast muscle (p < .05) in the group receiving PO were observed. Additionally, oleic acid content in the breast muscle was significantly higher in the EOs supplemented groups (p < .01). Quails fed the PO supplemented diet had higher villus and relatively rich in oleic acid. The expression levels of IGF-1 and myogenin genes in quail's muscle were not affected, but the expression of avUCP gene was significantly lower in quails fed with LMO and alpha-Tops (p < .05). The results demonstrated variable effects of these treatments on intestinal morphology. Taken together, dietary inclusion of EOs is found to be beneficial and hence can be recommended for improving the quality of poultry meat.
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    Effects of feeding plant-derived agents on the colonization of Campylobacter jejuni in broiler chickens
    (Elsevier, 2014) Kurekci, Cemil; Al Jassim, Rafat; Hassan, Errol; Bishop-Hurley, Sharon L.; Padmanabha, Jagadish; McSweeney, Christopher S.
    The aim of this work was to test the potential use of plant-derived extracts and compounds to control Campylobacter jejuni in broiler chickens. Over a 7-wk feeding period, birds were fed a commercial diet with or without plant extracts (Acacia decurrens, Eremophila glabra), essential oil [lemon myrtle oil (LMO)], plant secondary compounds [terpinene-4-ol and a-tops (including a-terpineol, cineole, and terpinene-4-ol)], and the antibiotic virginiamycin. Traditional culture and real-time quantitative PCR techniques were used to enumerate the numbers of C. jejuni in chicken fecal and cecal samples. In addition, BW and feed intake were recorded weekly for the calculation of BW gain and feed conversion ratio. The mean log(10) counts of C. jejuni were similar (P > 0.05) across treatments. However, significantly lower levels of fecal Campylobacter counts (P < 0.05) were recorded at d 41 for the a-tops treatment by culture methods. No differences (P > 0.05) in BW gain were obtained for dietary supplementation, except for the E. glabra extract, which had a negative impact (P < 0.001) on BW, resulting in sporadic death. Results from this study suggest that supplemental natural compounds used in the current study did not reduce the shedding of C. jejuni to desired levels.
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    Review of australian species of Megastigmus (Hymenoptera: Torymidae) associated with Eucalyptus, with descriptions of new species
    (2010) Do?anlar, Mikdat; Hassan, Errol
    The species of Megastigmus Dalman 1820 (Hymenoptera: Chalcidoidea: Torymidae), related with Eucalyptus species (Myrtaceae) from Australia were reviewed. A total of 33 species of Megastigmus were studied, with nine species described as new: chrisburwelli, erolhasani, judikingae, lawsoni, leptocybus, rieki, thailandiensis, thitipornae, zvimendeli. Three new synonymies are created: adelaidensis Girault syn.new = maculatipennis Girault, ater Girault syn.new = tasmaniensis Girault, trisulcus Girault syn.new = voltairei (Girault). All species were described in detail, with photographs of their diagnostic characters and available biological data provided. Some new diagnostic characters of the genus were found and added to the generic diagnosis of earlier authors. An identification key is provided for the treated Megastigmus species. Species of Megastigmus were recorded as parasitoids of the gall inducer insects or as a gall inducer in several parts of plants. © 2010, INSInet Publication.
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