Volume 63 (2019): Edizione 3 (September 2019)

The purpose of this study was to detect the antibiotic resistance of forty-one Escherichia coli isolates from the intestinal contents of slaughtered broiler chickens using the disk diffusion method according to Kirby-Bauer. Mueller-Hinton agar plates were inoculated with 0.1 ml overnight broth cultures of individual E. coli isolates and the disks with the following concentrations of antibiotics were applied onto them: ampicillin (10 μg), cefotaxime (30 μg), gentamicin (10 μg), streptomycin (10 μg), azithromycin (15 μg), tetracycline (30 μg), ciprofloxacin (30 μg) and levofloxacin (3 μg). After the incubation at 37 °C for 16—18 hours, the inhibition zones were measured and interpreted in accordance with the Clinical and Laboratory Standard Institute (CLSI) zone diameter breakpoints. Almost all E. coli isolates showed resistance to tetracycline (92.68 %), most of them were resistant to gentamicin (75.61 %) and levofloxacine (70.73 %). Phenotypic resistance to tetracycline was further confirmed with the help of the Polymerase Chain Reaction (PCR) procedure focused on the presence of specific tet(A) and tet(B) genes. These genes were detected in all 41 E. coli isolates. On the contrary, E. coli isolates were highly susceptible to both azithromycin and streptomycin. In conclusion, the study highlighted the role of commensal E. coli bacteria isolated from the intestines of broiler chickens as an important reservoir of tetracycline resistance genes.

The objective of this study was to use the “Screening test for antibiotic residues” (STAR) as a broad-spectrum detection method for antibiotic residues in poultry meat. The STAR method is a microbiological inhibition assay (a five plate test) where the development of inhibition zones (IZs) indicates the presence of antibiotic residues in meat samples. By using the STAR method, in a total of 13 poultry products providing 18 meat samples (14 muscle and 4 skin) and 18 corresponding juice samples, 11 out of the 18 samples were positive for containing antibiotic residues. Based on muscle alone (which is the matrix validated for use in the STAR method), 6 of the 14 muscle samples were positive for antibiotic residues. The STAR method as a screening technique proves advantageous as it is relatively easy to perform and of a low cost. Furthermore, the STAR method not only indicates the presence or absence of antibacterial substances, but simultaneously, a positive sample gives an indication of the antibiotic family present due to the use of five different bacterial test organisms. Families of antibiotics pre-identified due to positive samples in the results of this study include aminoglycosides (one out of 18), beta-lactams and sulphonamides (6 out of 18), and macrolides (5 out of 18). Such pre-identification of the antimicrobial families allows for a targeted confirmatory analysis. However, one could argue that the STAR method is laborious and time consuming. Overall, given the potential for false positive/negative results, further confirmatory method analysis of the samples must be performed to ensure that the results and conclusions drawn here are true.

The aim of this study was to determine in a model experiment the potential residues of bromadiolone and brodifacoum in the wheat grown on soil treated with these rodenticides and to compare them with the respective acceptable daily intake (ADI) in order to obtain information lacking in the scientific literature. The study focused on the level of residues of chronic rodenticides Broder G, with the active ingredient brodifacoum, and DERATION G, with the active ingredient bromadiolone, in wheat (Triticum spp.). The preparations were used in the form of granular bait. In the wheat grown on the soil treated with 100 g.m⁻² of the preparation BRODER G, the brodifacoum residues ranged from 0.012 to 0.0218 mg.kg⁻¹, while the treatment of soil with 500 g.m⁻² resulted in residues ranging between 0.0344 and 0.0436 mg.kg⁻¹. When using the preparation DE-RATION G, bromadiolone residues ranged between 0.012 and 0.018 mg.kg⁻¹ after the treatment of soil with 100 g.m⁻² and between 0.030 and 0.0428 mg.kg⁻¹ after the treatment with 500 g.m⁻². We observed that the acceptable daily intake was exceeded significantly in all of the cases and the residual levels depended on the rodenticide dose. In the case of brodifacoum, the ADI was exceeded more than 700-fold at a dose of 100 g.m⁻² and more than 1400-fold at a dose of 500 g.m⁻² of soil. With bromadio-lone, the ADI was exceeded 150-fold at a dose of 100 g.m⁻² and more than 350-fold at a dose of 500 g.m⁻². This indicates the risk to consumers from such crops.

The aim of this study was to evaluate the toxigenic potential of Bacillus cereus strains isolated from frozen goat colostrum. Of the 50 phenotypically suspected B. cereus isolates, 39 (78.0 %) were confirmed as B. cereus by the polymerase chain reaction (PCR) method based on the gyrB gene detection. In these isolates, genes encoding the production of haemolysin BL (Hbl), a complex of non-haemolytic enterotoxins (Nhe) and emetic toxin were detected by the PCR method. In 36 (92.3 %) confirmed B. cereus isolates, genes encoding at least one type of toxins of interest were detected. In all toxigenic isolates, we found the presence of genes for Nhe production, and in 16 (41.0 %) of the isolates, genes encoding both Nhe and haemolysin BL were shown. Eight (20.5 %) of the emetic strains of B. cereus were identified. The emetic toxin production gene was always detected simultaneously with genes encoding non-haemolytic enterotoxin production. The ability to produce BL haemolysin and non-haemolytic enterotoxins were confirmed by the immunochromatographic method. In summary, goat colostrum can be a significant source of toxigenic strains of B. cereus.

This investigation estimated the anti-oxidative potential of Aloe barbadensis gel extracts in rats against alcohol-induced oxidative stress. Thirty male albino rats (5 each per group) were included in the experiments. Group A (positive control) and B (negative control) were administered 4 mg.kg–1 body weight distilled water and 50 % alcohol respectively for 21 days. Groups C and D were administered 50 % alcohol for the first 14 days followed by co-administration of 125 mg and 250 mg.kg⁻¹ body weight extract with alcohol respectively for the last 7 days. Groups E and F were administered distilled water for the first 14 days followed by co-administration of 125 and 250 mg.kg⁻¹ body weight Aloe barbadensis gel extracts with distilled water respectively for the last 7 days. The administration of alcohol resulted in a significant (P < 0.05) decrease in the specific activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and reduced glutathione (GSH) levels, while cholesterol (CHO), triglycerides (TAG), nitric oxide (NO) and malondialdehyde (MDA) concentrations were significantly increased when compared to the controls. Co-mobilization with Aloe barbadensis gel extracts for 7 days significantly reversed the deleterious effects of alcohol in the treated groups when compared to the alcohol group. This study indicated that Aloe barbadensis probably possesses anti-oxidative effects against alcohol–induced oxidative stress in rats.

Clinoptilolite (Cp) is the most common and suitable natural zeolite type for many commercial and industrial applications. Recent studies have also shown a high potential of clinoptilolite in various medical applications. The aim of our study was to evaluate the effect of long-term peroral administration of clinoptilolite on appetites, the consistency of faeces, and the histopathology of the intestines of growing pigs. Fourteen Landrace × Large White crossbred pigs of both genders, a few days after weaning (12.95 kg b. w.), were divided into two equal groups. The control group was fed with a basal feed mixture, and the experimental group with a feed mixture supplemented with 2 % of natural zeolite (the commercial preparation “ZeoFeed”). The appetite, clinical state and consistency of the faeces were assessed every day. The blood samples were collected on days 0, 21, and 42 of the experiment. Histological examinations of the intestines from the control and experimental animals were carried out at the end of the experiments. The supplementation of 2 % Cp did not affect neither the appetite nor the clinical state of the pigs. The faecal consistency score in the experimental animals was 18.82 % lower than that of the control piglets. The histopathological evaluations showed protective evidence of the Cp on the intestinal tract wall in the duodenum and jejunum.

The aim of this study was to evaluate ovarian activity and the size of oocytes in ovarian follicles in sexually mature Landrace-Yorkshire gilts in relation to the individual seasons of the year. The study was carried out on 240 gilts slaughtered at an abattoir during the four yearly seasons. The size and weight of the ovaries, the number of follicles and corpora lutea (CL) according to individual size categories were evaluated. The oocytes were aspirated from follicles and their sizes were measured. Our evaluation of the size of the ovaries showed that they were the largest in autumn, when their mean length reached 25.8 ± 3.4 mm, while in winter their mean length was 24.2 ± 2.9 mm. The smallest weight of the ovaries was determined in autumn (mean 5.7 ± 1.4 g) and the highest in spring (mean 6.2 ± 2.2 g). The largest number of follicles in the ovaries of the gilts was recorded during the autumn months, with a predominance of follicles up to 3 mm (mean number 17.9 ± 7.5). The largest number of corpora lutea was observed in spring (mean number 12.1 ± 2.6) and the smallest in winter (mean number 6.1 ± 1.1). The oocytes from follicles of up to 3 mm size, were the smallest in spring (mean size 16.99 × 10³ ± 3.42 × 10³ µm²) and the largest in winter (mean size 18.90 × 10³ ± 2.99 × 10³ µm²). In total, the largest oocytes were aspirated from 4—6 mm follicles in autumn (mean size 19.60 × 10³ ± 5.37 × 10³ ± µm²). The values recorded indicated that the seasons affected the ovarian activity and the growth of oocytes in gilts.

Collagen and elastic fibres are generally present in organs whose normal function requires great resistance and elasticity. The aim of this study was to localize the collagen and elastic fibres in the stroma of the bovine lactating mammary gland and to determine their role in the process of milk ejection. For this purpose, the histochemical staining for collagen and the immunohistochemical method for the detection of elastin were used. The accumulation of scattered collagen fibres was observed between and inside the lobules where they formed distinct septa. Between secretory alveoli, the collagen fibres were found to be concentrated into two incomplete layers surrounding the blood capillaries. Bundles of elastic fibres in high density were located in the interlobular spaces. A dense network of elastic fibres was located between adjacent alveoli. Elastic membranes were located beneath the secretory epithelium. The high concentration of the collagen and elastic fibres indicated, that both types of fibres play a significant role in the resistance during the secretory stage and in the recoil of the mammary gland after milk ejection.

Highly pathogenic avian influenza (AI) disease has occurred in many countries globally adversely affecting domestic poultry production. Ghana recorded her first outbreak of a highly pathogenic avian influenza (HPAI) in 2007 on a small scale commercial farm in Tema. Since then, there have been numerous outbreaks. The source of these outbreaks is not conclusive. The role of wild birds in the epidemiology of avian influenza outbreaks in Ghana is not known. This study sought to investigate the role of wild birds in the outbreaks of Highly Pathogenic Avian Influenza (HPAI H5N1) in Ghana, particularly in Southern Ghana. Wild birds were trapped and sampled through mist netting. The faecal and tracheal samples were analysed using a One-Step Real Time Reverse Transcription Polymerase Chain reaction (RT-PCR) with primer sets targeting the matrix protein gene of the Avian influenza virus. Sera samples were subjected to multispecies competitive Enzyme Linked Immunosorbent Assay (ELISA) for anti-AI virus antibodies. Three hundred and twenty two (322) wild birds were trapped and sampled. Birds sampled included 87.3 % (281/322) resident birds and 12.7 % (41/322) migratory birds. The migratory birds included intra-African migrants 12.2 % (5/41) and Pale-arctic migrants 87.8 % (36/41). Avian influenza virus and antibody were neither detected in these swabs nor sera samples, respectively. The study documented the absence of AI in resident and migrant wild birds in the study area and suggest that wild birds may not be responsible for the outbreaks of AI in the poultry. However, sustained surveillance is recommended to ascertain a nationwide successful prevention and control strategy to stay the tide of any future intruding AI outbreaks.

The aim of this study was to evaluate the occurrence of mastitis and its impact on the reproductive parameters in a herd of 180 dairy cows. Based on the herd records 127 cows of Slovak spotted cattle and their crosses with red Holstein were selected for study between 1—2 months after calving. The examination of the health status of the mammary glands consisted of: the clinical examination of the udder, the California mastitis test (CMT) supplemented by the collection of mixed milk samples, and the laboratory examination of bacterial pathogens causing the mastitis. In addition to the mam­mary investigation, reproduction indicators such as the length of the insemination interval, the service period, the intercalving period and the insemination index were also analyzed. The results of this study indicated: a high incidence of mastitis (41.6 %), especially latent (21.2 %), subclinical (15.7 %) and clinical (4.7 %) forms were most common in the herd. The most frequently isolated bacteria from the infected milk samples were: coagulase negative staphylococci (54.1 %), S. aureus (16.9 %), Streptococcus spp. (15.0 %), A. viridans (7.5 %) and Ent. faecalis (6.4 %). According to the available literature, the optimum values of the intercalving period were 365—400 days, the insemination interval 55—80 days, the insemination index 1.2—2 and the service period 60—110 days. In comparison, our results showed increased, unsatisfactory reproductive values in the group of dairy cows with clinical mastitis. While in healthy cows as well as in groups of cows with latent and subclinical mastitis, all of the reproductive indicators were within the optimal levels.