فصلنامه دامپزشکی ایران
سال شانزدهم شماره 69 (زمستان 1399)

Peste des Petits Ruminants (PPR) is a severe, highly infectious and fatal viral disease of small ruminants. Four lineages of PPR virus have been identified globally based on sequence analysis nucleoprotein (N) and fusion (F) gene. The aim of this study was molecular detection and phylogenetic analysis recently circulating PPR virus in small ruminants in QOM Province in Iran. A total of 10 anti-mortem samples (mesenteric lymph node) were collected from clinically suspicious animals and examined for the presence of PPRV by a one-step RT-PCR assay. Samples positive with RT-PCR were subjected to subsequently genetically characterized by sequencing of the nucleoprotein (N) gene and phylogenetic analysis of PPR virus (PPRV) strains.

Of the 10 clinical samples examined, 40.0% were positive with RT PCR for viral nucleic acid. The nucleotide sequence and phylogenetic analysis indicated that these isolates were clustered genetically with Lineage IV isolates of the PPRV. Conclusion and

phylogenetic analysis and molecular findings of this study confirmed active lineage IV PPRV infections among goat populations in QOM Province.This study and latter studies revealed that the Iranian PPRV isolates belong to lineage IV and are closely related to the Pakistan, Tajikistan and India isolates of PRPV. We recommended that more studies should be done from other parts of the country, especially the border areas, in order to more accurately illustrate the status and circulation of the active lineage of the PPR virus in Iran.

The aim of this study was to the determination of prevalence of resistant Escherichia coli isolates to commonly used β-lactam antibiotics and some related resistance genes in sheep. Totally, 67 E. coli isolates from 67 healthy sheep were considered to determine resistance against 9 antibiotics belonging to commonly used beta-lactam antibiotics by disc diffusion method. Also, the presence of blaTEM, blaSHV and blaCTX-M genes was investigated by PCR. The results showed all isolates were resistant to at least one of the tested antibiotics. The high prevalence of resistant strains to cephalexin, cefotaxime and ceftazidime was 98.5%, 98.5% and 97%, respectively. Also, 5 samples (7.4%) were positive for ESBLs producing E. coli. The results of this study indicated an increasing rate of resistance to commonly used β-lactam antibiotics among sheep. Therefore, antibiotic prescription methods should be limited and prevention strategies should be considered against infections to avoid dissemination of antibiotic resistance in food-producing animals.

In poultry farms, the stresses are inevitable, therefore, it is very necessary to achieve an efficient and practical way to control and reduce its negatives effects. Thus, this study was conducted to evaluate the effects of different sources of chromium on thyroid hormones and some blood parameters of broiler chicks under physiological stress conditions. A total of 216 one day old Ross broiler chicks (male) were used in a 3 × 2 factorial arrangement with two stress conditions (no stress, stress) and three levels of additive (no Additive, 2000ppb chromium-methionine, and 2000ppb chrome-methionine mill) in a completely randomized design with 6 treatments, 3 replicates and 12 bird per each. Dexamethasone was added to the diet (1.5 mg/kg diet) during 24-18 days of age to induce physiological stress. The birds were fed with chromium diets from 18 d until the end of the experiment. Blood samples were taken at 24 and 46 days of age via brachial vein and then analyzed for blood glucose, lipids, cortisol, thyroxine (T4) and thyroid iodothyronine (T3). Physiological stress reduced the concentration of thyroid hormones, glucose, serum lipids and cortisol hormones. In stressed birds, the use of chrome methionine diet significantly reduced cholesterol of serum. Chromium supplementing diet increased thyroxine (T4) concentration. Dietary chromium methionine significantly decreased cortisol concentrations of serum. Based on the results, adding chromium ppb 2000 from various sources reduces the effects of physiological stress on thyroid hormones and cholesterol concentrations in the serum of birds under physiological stress.

Sperm-mediated gene transfer (SMGT) based on the intrinsic ability of sperms to bind and take-up of exogenous DNA was introduced in 1989. From that time on, it has been a challenging topic. One of the serious challenges was the motility of transfected sperms and hence their ability to fertilize the oocyte. The present study aimed to determine the effects of media and incubation conditions and also sperm parameters on the transfection of ovine spermatozoa by foreign DNA. In this study, the effects of various incubation temperature (5, 20 and 37 ºC), three different media (PBS, TCM and DMEM), presence of FBS in medium, viability and motility of sperms and sperm capacitation in DNA absorption rate and intensity were assessed by using rhodamine-labeled EGFP plasmid. Results showed that incubation of spermatozoa with plasmid in 37ºC leads to more transfection rate but various incubation media and presence or absence of FBS had no significant effect on DNA uptake rate and intensity. Motility rate and capacitation of sperms had no significant effects too. However, in sperms with a damaged membrane, the DNA uptake rate increased significantly. All of the spermatozoa with true DNA absorption (post acrosome absorption) were immotile and none of the examined treatments in this study could produce motile transfected spermatozoa. Regarding the results of this study, it seems that membrane-damaged spermatozoa incubated with foreign DNA can be used for SMGT-ICSI to produce transgenic animals.

Mycobacterium avium subspecies paratuberculosis (MAP) is known worldwide for its role in causing paratuberculosis (Ptb), a chronic incurable intestinal tract infection of ruminants. Concerns remain in place as the elusive MAP epidemiology and its potential zoonotic nature continue to challenge veterinarians across the world. Almost half a century since its initial reports, Ptb is still not a notifiable disease in Iran leading to the unfortunate lack of a public-funded control scheme. We undertook this study to extend our knowledge of the MAP population genetic in diverse hosts in Iran. During seven months, 35 MAP isolates collected from milk and feces obtained from sheep, goat and cattle originating 8 provinces plus a further eleven archived MAP isolates were genetically interrogated. The Collins strategy was conducted on examined isolates to differentiate between cattle and sheep types of MAP bacteria. The study was further expanded by RFLP-IS900 analysis using PstI in search for genetic diversity. The findings of Collins strategy showed that all animal species covered by the study were exclusively infected by 'cattle' strains. In genotyping, on the other hand, RFLP-IS900 analysis yielded 10 largely similar genotypes with five of them infecting multiple hosts. Nevertheless, no trace of varying profiles was detected in individual farms and conspecifics. These data, taken together with earlier observations by others, raise the question of the mysterious absence of sheep-type strains in Iran. Circulation of highly similar strains in Iranian farm ruminants might be an indication of a homogenic MAP population with a tendency for diversification started only recently. The extent of temporal and spatial characteristics of such diversification is still unclear and left for future works.

The dogs' relationship with their owners has made them one of the most popular pets. They can be a reservoir of many microbial pathogens, so they are important for public health. This study was performed to determine the phylogenetic backgrounds and antimicrobial resistance of E. coli isolates from healthy household dogs and their owners in Kerman province, Iran. Samples were taken regardless of antibiotic usage in the dogs. Based on the history of the animals, 90% of them had not used antibiotics during the few months before the study. 168 E. coli strains belonging to feces of healthy household dogs (n=49), their owners (n=49) and the people without a pet (n=70) were studied; phylogenetic sequences including chuA, yjaA and TspE4.C2 were screened by conventional polymerase chain reaction (PCR). The isolates were investigated phenotypically for antimicrobial resistance against 11 commonly used antibiotics in dogs which were erythromycin, streptomycin, enrofloxacin, oxytetracycline, cefotaxime, ampicillin, trimethoprim-sulfamethoxazole, amoxicillin-clavulanic acid, ceftazidime, ceftriaxone and kanamycin. E. coli isolates were classified into A, D, B1 and B2 phylogroups with the prevalence of 55.9%, 30.3%, 7.1% and 5.3%, respectively. Considerably, antimicrobial resistance to erythromycin and oxytetracycline were predominant while the lowest frequency of antibiotic resistance was detected against ceftriaxone, ceftazidime, amoxicillin-clavulanic acid and kanamycin. This study was performed on apparently healthy dogs so it could determine their carrier role for antibiotic-resistant E. coli strains. This research revealed that healthy household dogs should be considered as the significant reservoir of resistant E. coli isolates especially to erythromycin, oxytetracycline, streptomycin, enrofloxacin, cefotaxime and ampicillin which these resistant strains were mostly belonging to A and D phylogenetic groups.

This research was conducted to investigate the effect of different levels of protein (20 and 24%) and the replacement of methionine DL with L methionine on the expression of myogenic genes (atrogin-1 and MYF-5) using the RT-qPCR technique in Japanese quail. This experiment was done in the form of a 2×2 factorial with 4 treatments and 4 repetitions and 15 quail in each replicate. The first treatment included DL-methionine and 20% protein (control group). The second treatment consisted of L methionine and 24% proteins, and the third treatment included L methionine and protein 20% and the fourth treatment included DL-methionine and protein 24%. After 35 days of feeding and keeping the quails, with 8 hours interval of hunger, 2 quails were slaughtered in each replicate, and a piece of their chest has been removed immediately and was transferred to the laboratory with Liquid nitrogen, and froze in -80°c. After extraction of the whole RNA, its quality was measured and was used to generate and synthesis the cDNA. Eventually, the expression of myogenic genes was measured by the real-time PCR method. In this method, 𝜷-actin gene, as the source gene, was used to normalize the data. The results showed that by decreasing the protein level from 24% to 20%, atrogin-1 gene expression increased and the MYF-5 gene expression decreased. Also, the replacement of methionine DL with L-methionine did not have a significant effect on the expression of myogenic genes. The results indicated that DL-methionine could be replaced with L methionine, and a 24% protein level is more suitable than 20% in the Japanese quail diet.

Newcastle disease is a viral disease of poultry that is caused by type 1 paramyxovirus, from the Avulavirus genus and its fast and precise diagnosis is of high importance. Virulence of this virus depends on Fusion protein (F), one of six proteins of this virus, which can be used for detection of the virus virulence. So, this study aims to design new primers according to bioinformatics science progression and suggest a cheaper and easier method for the identification of Newcastle virus (NDV) as well as distinguish lentogenic from velogenic strains with higher sensitivity and specificity. First, all available strains of Newcastle viruses were collected from NCBI data bank using Blast tool and after multiple alignments, universal and specific primers were designed. In the next step, identification of NDV was set up using universal primers by PCR on cDNA of the control positive sample. Then differentiation of lentogenic from velogenic strains set up by ARMS (Amplification Refractory mutation system)-PCR (Polymerase chain reaction) using specific primers. Because the method was performed on cDNA obtained from reverse transcription reaction (RT), and because the PCR product of the first PCR reaction was used as a template for nested second PCR reaction it is called “nested RT-ARMS PCR”. Afterward, some samples from broiler farms were tested by this method and then compared by Real-Time PCR as a golden standard test. The results showed that sensitivity and specificity of identification of the virus and its strains were fully compatible in both methods. To sum up, this method which consumes a little bit more time but lower expenses, equipment and complexity in comparison with Real-Time PCR, can be suggested as a suitable substitution for the detection of NDV and distinguishing its velogenic from lentogenic strains.

Medetomidine and dexmedetomidine are the two new alpha-2 agonists available for use in veterinary anesthesia. These drugs are employed for sedation and premedication in small animals. The present study aimed to investigate the effects of medetomidine and dexmedetomidine alone and in combination with acepromazine on sedation, cardiovascular function and electrocardiography in dogs. Sixty dogs were randomly divided into four equal groups. The dogs received one of the treatments of medetomidine (10 μg/kg), dexmedetomidine (5 μg/kg), medetomidine (10 μg/kg) with acepromazine (0.05 mg/kg) and dexmedetomidine (5 μg/kg) with acepromazine (0.05 mg/kg) intramuscularly. Sedation levels, heart rate, non-invasive arterial blood pressure, respiratory rate, body temperature and electrocardiogram were carefully recorded in dogs up to 20 minutes after administration. Sedation scores were significantly higher in groups of medetomidine with acepromazine and dexmedetomidine with acepromazine, at 5 and 20 minutes in comparison to groups of medetomidine and dexmedetomidine alone. Comparison of sedation scores in each group showed a significant increase over time. The comparison of heart rate, within the groups, showed a significant decrease when compared with the baseline value. The respiratory rate showed a decreasing trend in all groups over time. The amplitude of the P wave decreased and the P-R and Q-T intervals increased during the evaluation period in all groups. Sinus arrhythmia, AV-block grade 1, and sinus arrest were seen after the administration of sedative drugs in all groups. In conclusion, it is inferred that the addition of acepromazine to medetomidine and dexmedetomidine increases the sedation level. Heart rate decreased in medetomidine and dexmedetomidine groups and the addition of acepromazine exacerbated this decrease. The combination of acepromazine with medetomidine and dexmedetomidine did not also reduce the occurrence of arrhythmias in the dog.

Resistin is a hormone secreted from adipose tissue that plays an important role in regulating energy homeostasis and glucose metabolism. In humans, only a small amount of resistin is expressed in adipose tissue and is most commonly found in the bone marrow, spleen, lung tissue, and placenta. The purpose of this study was to investigate the effect of oral administration of selenium and selenite sodium nanoparticles on the transcription rate of the resistin gene in pregnant ewes. For this, 20 pregnant ewes were randomly selected and divided into four groups and were administered daily for 10 days leading up to birth. In treated group 1 sodium selenite (0.1 mg/kg body weight), while in treated groups 2 and 3 selenium nanoparticles (at doses of 0.05 and 0.1 mg/kg body weight, respectively) were administered. The fourth group was received distilled water and served as a control group. At the time of parturition, samples were taken from the placenta and the transcription rate of the resistin gene was determined by RT-PCR Real-Time based on a comparison assay of 2-ΔΔCt. The results showed that oral selenium administration to pregnant ewes caused a significant increase in the amount of resistin gene transcription rate which the role of sodium selenite was more pronounced than that of selenium nanoparticles (With p, equal to 0.002, 0.002 and 0.001 respectively).

Environmental and hosts risk factors are considered as two essential elements in epidemiological studies of infectious diseases. The severity of the infection and also the chance of transmission of pathogenic Leptospira interrogans bacteria from herbivores to humans have always been exposed to environmental and hosts risk factors. This study aimed to investigate the presence of serum reaction in the equid's population of Lorestan province and the determination of native serovars as well as evaluation of the role of environmental and host factors on seroprevalence. A total of 327 equids including 223 horses, 46 mules, and 58 donkeys were sampled and sera samples evaluated against 7 different Leptospira interrogans serovars. Geographical location and environmental conditions of sampled areas were recorded to be used in statistical surveys. The results showed that the serum positive reaction rate in horses, mules, and donkeys was 18.38, 10.87 and 3.45%, respectively. Host risk factors such as sex, age, and breed were effective on serum response rate and a significant difference was found. Canicola serovar with 46.34, 100 and 60% infection in horses, donkeys, and mules, respectively was the most common infective serovar; but a significant difference was not observed between animal species. Also, the results indicated that annual temperature of the environment and altitude at sea level of sampled location have a significant effect on seroprevalence of leptospirosis, but relative humidity and annual rainfall did not have a significant effect. Results of the current study proved that infection with Leptospira interrogans, although in Lorestan province is less severe than in other parts of the country, the most important native serovar of this region is canicola.

This experiment was conducted with the aim of the effects of pellet and mash feed on the production index, intestinal morphology characteristics, index of ascites, quality and microbial count of litter in broiler chickens using three diets of pellet, mash, mash+pellet on broiler performance. This experiment was conducted in a completely randomized design with three treatments and four replicates during 42 days. The measured traits included production index, intestinal morphology traits, ascites, hematocrit percentage, litter moisture and nitrogen content and microbial count of litter. In the whole of the total period, the results showed that the highest production indexes were pellet and pellet+mash treatments. The results of the morphological traits of the intestine showed that pellet and pellet+mash treatments had the highest ratio of villus height to the crypt depth in jejunum and the lowest level of mash treatment was observed. The results showed that the high ratio of villus height to the crypt depth in jejunum resulting from the use of pellet and pellet+mash ration due to production index was improved. The consumption of mash and pellet+mash treatments in the first three weeks reduced ascites significantly and increased with the prolonged feeding period of the pellet diet. The pellet+mash and all-flour treatments had the lowest amount of moisture content and nitrogen content, and as a result, the microbial count of litter was lower than that of pellet treatment. The pellet+mash treatment had the lowest index of ascites (32.62%) and less hematocrit (36%). The final result was that the use of pellet+mash treatment had the highest production index and the most suitable litter quality and the lowest ascites and microbial count compared to the full pellet diet in broiler chickens.