Iranian Journal of Veterinary Research
Volume:22 Issue: 1, Winter 2021

Listeria monocytogenes is an opportunistic intracellular foodborne pathogen and is ubiquitous in nature. The occurrence of L. monocytogenes in animal production units coupled with their presence in milk, faeces, feed, water, sewage, and soil is a contributory factor for foodborne listeriosis in humans and animals.

The study was aimed to characterize genotype and serogroup of L. monocytogenes recovered from different types of samples and also to study antimicrobial patterns by phenotypic and genotypic methods.

Multiplex polymerase chain reaction (PCR) was used for the confirmation of L. monocytogenes, the identification of its serogroup and lineage, and the detection of virulence markers. Enterobacterial repetitive intergenic consensus (ERIC), and randomly amplified polymorphic DNA (RAPD)-PCR were used to characterize those isolates, and antimicrobial patterns were studied phenotypically by Kirby-Bauer method and genotypically by PCR.

Out of the screened 474 samples (274 milk and 50 each of soil, feed, sewage, and beef), ten L. monocytogenes isolates (milk=8, soil=1, and beef=1) were confirmed by PCR targeting the hlyA gene and found to belong to the 1/2a, 3a serogroup and fall under type II lineage. Virulence potential assessment revealed that all the ten isolates harbored the iap gene while the presence of plcA and plcB genes were noticed in seven and eight isolates respectively. Six isolates from milk were found to group in the same cluster by ERIC and RAPD fingerprinting, suggesting both methods to be efficient molecular typing tools for L. monocytogenes. Genotypic characterization of antimicrobial resistance (AMR) genes revealed that seven isolates were positive for tetM, five for mefA, four for msrA, and one for lnuA genes while none of the isolates showed tetK, ermA, ermB, and lnuB genes.

The presence of L. monocytogenes in bovine farm environments coupled with virulence markers, and multidrug resistance from the study area suggest a possible transmission from the environment to humans and animals which needs to be monitored regularly to ensure food safety and the well-being of animals and humans.

Lameness in dairy cattle is prevalent worldwide and has serious economic and welfare implications. Nevertheless, it is an overlooked and least studied dairy problem in Pakistan.

This study was executed for in vivo and in vitro evaluation of antimicrobials and disinfectants against bacterial pathogens from hoof lesions of commercial dairy cattle.

For in vitro studies, 23 bacterial isolates (n=10 Staphylococcus aureus, n=8 Fusobacterium necrophorum, and n=5 Bacteroides) from hoof lesions were used for antimicrobial and disinfectants susceptibility testing. In vivo trials were carried out among 4 groups of dairy cows suffering from hoof lesions using different combinations of antimicrobials, non-steroidal anti-inflammatory drugs (NSAIDs), and disinfectants either parenterally or topically.

Results indicated that most of the isolates of S. aureus, F. necrophorum, and Bacteroides were resistant to penicillin, amoxicillin, trimethoprim + sulphamethoxazole, oxytetracycline, and tylosin. Ciprofloxacin and gentamicin were the most effective antimicrobials (in vitro) against all three bacterial pathogens. Comparison of in vitro efficacy of disinfectants showed that copper sulfate was the most effective disinfectant against the three pathogens followed by povidone-iodine and chloroxylenol. In vivo trials revealed that ciprofloxacin at 5 mg/kg/day intramuscular (IM) for 7 days, flunixin meglumine at 2.2 mg/kg/day IM for 7 days, and copper sulfate (5% solution) as foot-bath twice daily for 21 days was the most effective treatment regimen to treat lameness in commercial dairy cows.

It was concluded that in vitro antibiogram and disinfectant studies were useful tools to assess the effectiveness of routinely used antimicrobials and disinfectants for the treatment of lameness.

Rodents harbour a number of parasites of public health importance, thus, they threaten human health and livestock.

The present study aimed to characterize two helminthic species found in commensal rodents and record histo-physiological alterations induced by them.

A total of 300 synanthropic rodents of three species: Rattus rattus (n=201), Bandicota bengalensis(n=90), and Mus musculus(n=09) were live trapped and necropsied in different seasons during November 2017 to October 2019 at Ludhiana, Punjab, India.

Liver of two species B. bengalensis (72.22%) and R. rattus (65.67%) were found infected with two helminthic parasites Taenia taeniaeformis, and Calodium hepaticum. These endoparasites were present either alone (4.33-6.33%) or as mixed infection (65.55%). The level of total proteins and liver marker enzymes including aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were found significantly higher in the liver of rodent species infected with single and mixed infection compared to those with no infection. In histopathological assay, granulomatous liver lesions and necrosis of hepatocytes were seen which were associated with eggs and adults of C. hepaticum and inflammatory reaction in hepatic parenchyma adjoining to cysts of T. taeniaeformis. Based upon scanning electron microscopy (SEM) identification and molecular characterization using mitochondrial cytochrome oxidase I (COI) region, the metacestodes in whitish cysts were confirmed to be of T. taeniaeformis for the first time in Punjab, India.

The study highlights an alarmingly high infection of rodents with zoonotic parasites and suggests immediate pest (rodent) control to check the dissemination of zoonotic diseases by helminth species under study.

The emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA) in the food industry have led to using alternative natural bioagents for controlling S. aureus in food.

The current work aimed to isolate and characterize a lytic phage specific to S. aureus and evaluate its efficacy with thyme essential oil for controlling S. aureus growth in chicken fillets.

Twenty S. aureus strains previously isolated from ready-to-eat chicken products were tested for antimicrobial susceptibility and used for phage isolation.

All S. aureus strains were multidrug-resistant (MDR). The isolated phage (vB_SauM_CP9) belonged to the family Myoviridae and maintained its stability at pH (4-9) and temperature (30-70°C). The phage showed lytic activity on ten S. aureus strains and had a burst size (228 PFU/infected cell), latent period (45 min), and rise period (15 min). A combination of S. aureus phage multiplicity of infection (MOI) 10 + thyme oil 1% caused a higher significant reduction in S. aureus growth (87.22%) in artificially inoculated chicken fillets than individual treatment with bacteriophage or thyme essential oil.

To our knowledge, this is the first report to evaluate the efficacy of bacteriophage and thyme oil for controlling the growth of MDR S. aureus in chicken products and recommending application of S. aureus phage and thyme oil combination in the food industry to achieve food safety goals and consumer protection as well as mitigate the antimicrobial resistance crisis.

Lipids play a vital function in a bird’s body and to improve the lipids utilization and their absorption in a bird’s digestive system, emulsifiers are suggested.

This study evaluated and compared the effects of lecithin (LEC) and lysophosphatidylcholine (LPC) emulsifiers on broiler chicken’s productivity traits and physiological indicators such as blood plasma parameters, intestine traits, short-chain fatty acids (SCFA) profile in caecum’s content, caecum’s villus height and crypt depth and their ratio.

900 Ross 308 broiler chickens were assigned to 3 groups with 6 replicate pens and fed with a standard compound diet (SCD) and an SCD supplemented with 0.05% LEC and 0.05% LPC. Body weight (BW), average daily gain (ADG), daily feed intake (DFI), feed conversion ratio (FCR), and dry matter (DM) content of the litter were recorded. At the end of the trial, 10 birds from each group were randomly selected and euthanized. Blood samples were collected, and blood plasma analysis was performed. Intestinal samples were collected post-mortem and intestinal traits, SCFA profiles, and intestinal histomorphometric were measured.

The inclusion of lysophosphatidylcholine significantly increased the broilers’ BW and ADG at their fifth week of age (P<0.05). Lecithin increased the low-density lipoprotein cholesterol (LDL/C) concentration in blood plasma (P<0.05). Butyric and isovaleric acid concentrations significantly increased by LPC and reduced by LEC (P<0.05). Lecithin and LPC caecum’s villus heights were significantly increased (P<0.05), and caecum’s crypt depth was also increased in LEC compared to SCD (P<0.05).

As an emulsifier, lysophosphatidylcholine can improve the broilers’ weight, but LEC showed better effects on their physiological indicators by improving intestinal mucosal absorption areas in caecum.

Docetaxel is beneficial in oocyte cryopreservation.

The effect of docetaxel, on the survival, fertilization rate and mRNA expression of apoptosis-related genes of vitrified mature oocytes was investigated.

Mature oocytes were divided into eight experimental groups, including I) control, II) docetaxel, III) docetaxel + cryoprotectant agent 1 (CPA1), IV) docetaxel + CPA2, V) docetaxel + vitrification 1 (Vit1), VI) docetaxel + Vit2, VII) Vit1, and VIII) Vit2. The survival and fertilization rates, and the mRNA expression level of Bcl-xl, Bax and caspase-3 as apoptosis-related genes were evaluated.

The survival rates in Vit1, and Vit2 groups were significantly lower than in the control group (P<0.05). The fertilization rates in docetaxel + Vit1, docetaxel + Vit2, Vit1, and Vit2 were significantly lower than the control, docetaxel, and related groups using docetaxel and CPAs. Bax expression was significantly increased in groups which oocytes vitrified. Also, its expression in the Vit2 group increased significantly in comparison to the docetaxel + Vit2 group. The expression of the Bcl-xl gene was downregulated in docetaxel + CPA2, docetaxel + Vit2 and Vit2 compared to docetaxel group. The Bax/Bcl-xl ratio significantly increased in docetaxel + CPA2, docetaxel + Vit1, docetaxel + Vit2, Vit1 and Vit2 groups compared to control, docetaxel and the docetaxel + CPA1 group. Caspase-3 expression significantly increased in all six groups in comparison to the control, and docetaxel groups. Its expression significantly increased in the Vit1 and Vit2 groups in comparison with docetaxel + Vit1, and docetaxel + Vit2, respectively.

Docetaxel ameliorates the damages to oocytes during vitrification by altering the expression of apoptosis-related genes and its effects are dependent on the vitrification solution used in cryopreservation of oocytes.

Clostridium perfringens causes necrotic enteritis (NE) and is considered a major economic burden in the broiler industry and a significant foodborne pathogen, worldwide.

Clostridium perfringens isolated from NE affected broiler chickens was aimed to characterize and the presence of β-lactamase and quinolone resistant genes were also investigated in the isolates.

A total of 224 intestinal and caecal specimens were collected from NE affected broiler chickens and cultured to isolate C. perfringens. The toxicogenic characterization of C. perfringens was appraised using polymerase chain reaction (PCR) and antibiotic susceptibility testing (disc diffusion method). The selected C. perfringens isolates were characterized for β-lactamase and quinolone encoding genes by PCR analysis.

All isolates were cultured positive for C. perfringens and the toxin-encoding genes of C. perfringens (α-, β-, β2-, ε-, ι-, and enterotoxin) were also identified. About 65.6% of isolates had a multi-drug resistant (MDR) profile but none of these isolates were resistant or susceptible to all screened antibiotics. A subset of isolates, 160 and 98 were analyzed for β-lactamase and quinolone genes, respectively, and recognized blaTEM, blaSHV, and blaOXA in 64 (40%; CI: 32.35-48.03%; P<0.001) isolates, and qnrB and qnrS in 28 (28.57%; CI: 19.90-38.58%; P<0.001) isolates except qnrA.

Therefore, the isolates of C. perfringens were toxicogenic and carried β-lactamase, and quinolone resistance genes. Nowadays, the rational use of antibiotics and safe production of broiler chickens are the major concern to save public health.

Exposure to a high ambient temperature (HT) can cause heat stress, which has a negative impact on physiological functions. L-tryptophan (L-Trp) as a precursor of serotonergic and kynurenine (Kyn) pathways, has a calmative effect during different stress statuses.

This study was carried out to determine the influence of intraperitoneal injection of Trp on feeding behavior, rectal temperature, and some blood parameters in the heat stress condition.

L-tryptophan (25 and 50 mg/kg body weight, BW) was administered intraperitoneally during either HT (39°C) or control temperature (CT; 31°C) for 5 h whilst fed or fasted in 7-day-old chicks.

L-tryptophan caused elevation in decreased food intake and significantly decreased rectal temperature during acute heat stress at the dose of 50 mg/kg BW. Rectal temperature reduced in the fasted state at the dose of 50 mg/kg BW, and at the dose of 25 mg/kg BW Trp in the fed state in comparison with the other experimental groups. Reduction of serum glucose, triglyceride, and corticosterone levels was seen during the fed state. L-tryptophan had a significant reducing effect on the serum corticosterone level in the fasted state in comparison with the fed state, and also revealed a significant decline at the dose of 25 mg/kg BW on the elevated serum corticosterone under heat stress.

Administration of L-tryptophan leads to increase cumulative food intake and decrease rectal temperature during heat stress. Also, L-Trp causes to decline increased serum corticosterone level under heat stress and fasted state. These findings indicated the potential regulator role of Trp to modulate stress response in heat-exposed chicks.

Mammary epithelial cells (MECs) have been widely-used over the years as models to understand the physiological function of mammary disease.

This study aimed to establish a culture system and elucidate the unique characteristics of bovine mammary epithelial cells (BMECs) from the milk of Ukraine Holstein dairy cows in order to develop a general in vitro model.

The milk from a three-year-old lactating dairy cow was used as a source of the epithelial cell, characteristics of BMECs were examined using real time cell assay (RTCA), immunocytochemistry (ICC), reverse transcription-polymerase chain reaction (RT-PCR), and Western blot (WB).

The results showed that BMECs can be recovered from milk, grown in culture, and exhibit the characteristic cobblestone morphology of epithelial cells.

The established BMECs retained MEC characteristics and secreted β-caseins even when grew on plastic substratum. Thus, the established cell line had normal morphology, growth characteristics, as well as secretory characteristics, and it could be considered as a model system and useful tool for understanding the biology of dairy cow mammary glands.

Periostin (POSTN) is an extracellular matrix (ECM) protein that plays an important role in the metastatic process and cancer cell migration. As implantation is a similar mechanism to metastasis, it has been hypothesized that POSTN may also play a role in the implantation process.

The aim of the present study was to compare POSTN and progesterone levels during the early pregnancy stage in Damascus goats.

Forty goats were synchronized using progesterone based sponges and were mated upon estrus signs display. While ten goats were kept as control (CON) and were not allowed to mate. Blood samples were taken through jugular venepuncture from CON and synchronized goats on day 13, 15, 17, 19, and 21 of breeding. Progesterone and POSTN levels were determined by enzyme-linked immunosorbent assay (ELISA). Later the pregnancy diagnosis was confirmed by transabdominal ultrasonography on day 50 after mating.

Progesterone level was influenced by status of pregnancy and day of observation with an interaction between the status of pregnancy and day of observation in goats. Whereas POSTN level was only affected by the day of observation.

POSTN level did not vary with progesterone level during phase of embryonic implantation in goats; however, standardization and application of different procedures for POSTN assay in a large group of animals might be useful as an early pregnancy biomarker in goats.

It has become established that Helicobacter pullorum could be isolated from raw chicken meat.

This study was aimed to develop a novel culture method (protocol B) to isolate H. pullorum from chicken meat by adding some modifications to the traditional culture method (protocol A), and as a consequence to compare their sensitivity, specificity, and the accuracy of these methods with polymerase chain reaction (PCR) test.

400 chicken meat samples were collected from various retail markets and supermarkets. Each sample was processed by protocol A, protocol B, and PCR test.

Out of 400 samples, 77 (19.25%), and 163 (40.75%) were culture-positive by protocol A and protocol B, respectively. Using PCR test as a gold standard, 196 (49%) samples were identified as H. pullorum. The specificity for both protocols was determined 100%, while the sensitivity of protocol B and protocol A was assessed 83% and 39%, respectively. Also, the higher and lower accuracy belonged to protocol B (92%) and protocol A (70%), respectively.

The methodology designed herein can provide a suitable, approximately sensitive, specific, and accurate method to cultivate H. pullorum from chicken meat.