No abstract

In the present study, a total of 512 food samples composed of raw milk, dairy products, meat/meat products, chicken meat, seafood and raw vegetables were analyzed for the presence of Listeria monocytogenes. The results of the standard identification methods showed that 20 (3.9%) of the analyzed samples were found to harbor this pathogen. Further, 8.4% (13/155) of chicken meats, 0.9% (1/105) of meat/meat products and 13.6% (6/44) of fresh vegetables were contaminated with L. monocytogenes. Interestingly, only 18 of these isolates gave expected band size when they were subjected to molecular confirmation by polymerase chain reaction (PCR). Multiplex PCR serotyping of the strains revealed that 66.6% (12/18) of which belonged to serotype 1/2a (or 3a), 5.6% (1/18) to serotype 1/2b (or 3b, 7), 5.6% (1/18) to serotype 1/2c (or 3c) and 11.1% (2/18) to serotype 4b (or 4d, 4e). Two strains could not be serotyped by multiplex PCR. The strains were also evaluated by disk diffusion assay for their susceptibility to 15 commonly used antimicrobials. Antimicrobial resistance was most frequently observed for clindamycin (94.4%), followed by streptomycin and kanamycin (88.9%); penicillin (72.2%), tetracycline and gentamicin (66.7%); quinopristin/dalfopristin and erythromycin (61.1). Interestingly, 13 strains were resistant to more than five antibiotics. All strains were susceptible to linezolid, teicoplanin and vancomycin. Practical Applications Listeria monocytogenes is one of the most important foodborne pathogens responsible for several outbreaks and cases of listeriosis in human. This study focused on the prevalence of L. monocytogenes in different raw and ready‐to‐eat foodstuffs, and serotype distribution among the isolates. Antibiotic resistance profiles of the isolates were also reported. Information and relief provided to consumers could help elaborate public health and food safety.

Analysis of residual levels of tetracyclines (TCs) in chicken meat was performed using a validated liquid chromatography coupled with a tandem mass spectrometry (LC-MS/MS) technique. Overall, the recoveries for TCs ranged from 56.9% to 101.2%, with standard deviations of 4.5-13.2%. Detection limits ranged from 7.9 to 14.6 µg kg⁻¹. In four of 60 samples, doxycycline (DXC) was determined in a range from 19.9 to 35.6 µg kg⁻¹; and in one sample tetracycline was detected at 17.2 µg kg⁻¹. Chlortetracycline (CTC) and oxytetracycline (OTC) were not detected in any of the tested samples. This study indicates that chicken meat sold in Bursa, Turkey, contained some residues of TCs. Therefore, stricter regulations for the use of antibiotics in the poultry industry and the monitoring of drug residues in chicken meat prior to marketing are needed. Finally, this method has been applied successfully for the confirmation of TCs in chicken meat.

The aim of this study was to investigate the individual and combined effects of rosemary, oregano and fennel volatile oil (FVO) supplementation on the performance and ilio-caecal bacteriological flora of broiler chickens. A total of 800 male Ross-308 broiler chickens were divided equally into 8 groups; each contained 100 chickens. The study included a control treatment (NC) with no dietary additives that was supplemented with oils according to the following 7 treatments: 200 mg α-tocopherol acetate/kg (PC), 100 mg oregano volatile oil (OVO)/kg, 100 mg rosemary volatile oil (RVO)/kg, 100 mg FVO/kg and an equal mixture of oregano+rosemary+fennel VO (100, 200, 400 mg/kg, VOM-1, VOM-2 and VOM-3, respectively). The experiment lasted for 6 weeks. At the end of the experiment, dietary supplementation with α-tocopherol, oregano, rosemary and FVO and two different volatile oil mixtures (VOMs) (VOM-2; VOM-3) significantly increased the body weights (BWs) of broilers at 7, 14 and 21 d of age compared to the negative control (NC) (-) and VOM-1 groups. At 0-42 d, birds fed on VOM-3 were considerably heavier and also gained more weight than NC (-) and VOM-1 groups. The blend of VOs at 400 mg/kg significantly increased Lactobacillus spp. in faeces. The blends of oregano, rosemary and FVOs (VOM-3) at 400 mg/kg concentration and also VOM-3 group exhibited stronger antibacterial activity against coliform bacteria compared to the NC (-) group. In conclusion, the blend of oregano, rosemary and fennel VOs at higher concentrations (400 mg/kg concentration) in diets can be used to stimulate the growth and can improve the intestinal microbial balance (including a reduction of coliform bacteria and an increase in Lactobacillus spp. counts) of broiler chickens.

Twenty Holstein calves were used to investigate the effects of mannanoligosaccharides (MOS) supplementation in the whole milk on growth performance, faecal score, faecal pH, selected faecal bacterial populations and health during the preweaning period. Healthy calves selected by clinical examination were allocated to one of the two groups (control [CG] and experimental [EG]) at 5 days old. Each group consisted of 5 male and 5 female calves. Each calf in EG was supplemented with 7 g/d of a MOS product (Celmanax) from 5 days to 56 days of age. MOS supplement was mixed with the whole milk once in the morning and administered to the calves in EG via nipple bottle, whereas the calves in CG were fed the whole milk without MOS. Calves were weaned at 56 days of age. The final body weight, average daily weight gain (ADG) and average daily feed intake (ADFI) were statistically similar (p>0.05) but were higher by 3.70%, 6.66%, and 10.97%, respectively, in MOS than in control calves. Feed efficiency (ADG/ADFI) was also similar in two calves group. While faecal scores did not differ on day 5, 7, 14, 21, 28, 42, 49, and 56 between groups, EG had a higher faecal score (p = 0.05) than CG on day 35. Faecal concentration of Lactobacillus was lower (p<0.05) in EG compared with CG. No differences (p>0.05) in faecal concentrations of Bifidobacterium, Clostridium perfringens, and Escherichia coli were found between groups. Although there were no significant differences (p>0.05) in the incidence of diarrhoea, treatment days for diarrhoea and the costs associated with diarrhoea treatments between groups, collectively, the observed reductions in treatment days and the cost of diarrhoea treatments accompanying increases in final body weight, ADG and ADFI for EG may indicate potential benefit of MOS in treatment of diarrhoea.

In the period December 2008 to August 2009, 180 chicken meat samples, including 90 thigh and 90 breast meats in Bursa province, Turkey, were collected. The determination of chloramphenicol (CAP) residues in the samples was screened by ELISA, and a confirmatory method based on liquid chromatography coupled with tandem mass spectrometry was described and validated. The ELISA screening of the samples was performed after extraction with ethyl acetate and defatting with n-hexane. The results showed that 15 (8.3%) of the chicken meat samples were positive for CAP residues from 12.64 to 226.22 ng/kg, with a mean of 45.32 ng/kg. Confirmatory analysis of the results from ELISA was practiced after an extraction with ethyl acetate. Chromatographic seperation was carried out by using a Synergy MAX-RP 80A column and the mixture of acetic acid-water as a mobile phase. The mass spectral acquisition was done in the negative-ion mode applying selective reaction monitoring with the following ions (mass-to-charge ratio, m/z): m/z 321 → 152 and m/z 321 → 194 for CAP. By liquid chromatography-tandem mass spectrometry, CAP was confirmed in 2 of 15 ELISA positive samples and 1 of 45 negative samples, with concentration levels that varied between 150 and 361 ng/kg. The method was validated according to Commission Decision 2002/657/EC. The calibration curves were linear with a typical r(2) value of 0.9966. The recovery values ranged from 97.3 to 104.0% and within-laboratory repeatability was lower than 5%. The decision limit was 0.10 µg/kg and detection capability was 0.11 µg/kg. To evaluate the presence of CAP residues, this method was successfully implemented in chicken meat samples.

Fifty newborn Saanen kids were used to study the effects of inulin supplementation on faecal score, faecal pH, selected faecal bacterial population, BW, body temperature, haematological traits, selected health parameters and the incidence of diarrhoea. Kids were sorted by parity of their dams and multiple birth (twin or triplet) and assigned to one of the two groups (control: CG, and experimental: EG) at birth. Each group consisted of 25 kids. The groups were similar with regard to sex and birth weight. All kids were fed colostrum for the first 3 days after birth, and then the kids in EG were adapted to inulin supplementation by an increased dosage from day 4 to 7. Each kid in EG was supplemented with 0.2 g, 0.3 g, 0.4 g, 0.5 g and 0.6 g inulin on day 4, 5, 6, 7 and from day 8 to 28, respectively, whereas the kids in CG did not receive inulin. Faecal score and faecal bacterial population were not affected by inulin supplementation (P . 0.05). There were differences in faecal pH on day 14 (P 5 0.01) and 28 (P,0.05), whereas no difference in faecal pH on day 21 (P . 0.05) was detected between groups. No differences (P . 0.05) in BW and haematological traits were found between groups. Body temperature did not differ on day 14 and 21 (P . 0.05), whereas there was a difference in body temperature on day 28 (P 5 0.01) between groups. The numbers of kids with pneumonia and kids treated for pneumonia and diarrhoea were similar for CG and EG. Kid losses during the study were the same for CG and EG. The incidence of diarrhoea was not affected by inulin supplementation (P . 0.05). Inulin supplemented to kids did not adversely affect faecal score. The effect of inulin on faecal pH was not consistent. The results of our study suggested that daily dose (0.6 g) of inulin might not be enough to observe effects of it. Our data will be useful to determine the dose and timing of inulin supplementation in future studies investigating the effects of inulin on the parameters associated with performance and health status in kids and other young ruminants.

Quinolones have been extensively used for treatment of a variety of invasive and systemic infections of salmonellosis. Widespread use of these agents has been associated with the emergence and dissemination of quinolone-resistant pathogens. The quinolone resistance and plasmid-mediated quinolone resistance determinants (qnrA, qnrB, qnrS and aac(6')-Ib-cr) of 85 Salmonella isolates from chicken carcasses were investigated in this study. Isolates were serotyped according to the Kauffman-White-Le Minor scheme, and broth microdilution method was used to determine quinolone resistance. Plasmid-mediated quinolone resistance genes were investigated by real-time PCR and positive results were confirmed by sequencing. Among the Salmonella isolates, 30/85 (35%) and 18/85 (21%) were found to be resistant to enrofloxacin (MIC ≥ 2 mg/ml), and danofloxacin (MIC ≥ 2 mg/ml), respectively. All the isolates were negative for qnrA, qnrB and aac(6')-Ib-cr genes, nevertheless 2% (S. Brandenburg and S. Dabou) were positive for qnrS (qnrS1 determinant). This study is the first and unique investigating the plasmidmediated quinolone resistance determinants of Salmonella isolated from chicken carcasses in Turkey.