فصلنامه آسیب شناسی درمانگاهی دامپزشکی
سال سیزدهم شماره 2 (پیاپی 50، تابستان 1398)

Environmental temperature and photoperiod are among the important factors that may influence the reproductive cycle of various species. The aim of the present survey was to evaluate the different seasonal influences (cold= January and warm= July) and their intermediate seasons (April and October) on serum testosterone concentration in cats of Ahvaz region. For this purpose, one hundred and twenty adult male cats (domestic short hair breed) were examined. Blood samples were taken of thirty cats in each season, and testosterone concentration was measured using ELISA technique in serum samples. The average testosterone concentration of 3.42±0.49 ng/ml was detected in the studied cats. The minimum and maximum of serum testosterone level was also 0.01 and 17.2 ng/ml, in July and January respectively. The minimum of mean testosterone concentration was obtained in the warm season (0.62±0.23 ng/ml), while the maximum mean level was detected in the cold season (9.87±1.28 ng/ml). The mean testosterone concentration in spring and autumn was 2.26±0.5 and 0.94±0.3 ng/ml respectively. Environmental temperature and photoperiod correlated negatively with the testosterone concentration. The correlation coefficient between testosterone concentration with the average of minimum, maximum and total temperature, was calculated as R= -0.572, R= -0.615 and     R= -0.597 respectively. The correlation coefficient indicated an acceptable and high correlation of the negative (inverse) type, between testosterone concentration and photoperiod (R= -0.256). In conclusion, testosterone concentration is under the influence of season, with the mean testosterone concentration significantly lower in summer than the other seasons (p<0.05).

Consumption of gentamicin causes damage to cochlear part of ear and reversible kidney toxicity. Various compounds such as simvastatin have been suggested to reduce the side effects of gentamicin. The present study was conducted to investigate the effect of simvastatin in decreasing kidney damage due to gentamicin consumption in male Wistar rats. For this purpose, the rats were administrated simvastatin (5, 10 and 20 mg/kg daily) through gavage for 30 days. At the same time, they received gentamicin (40 mg/kg) intraperitoneally. The serumic levels of uric acid, sodium, potassium, BUN (blood urea nitrogen), creatinine, and albumin were measured and statistically analyzed using one-way analysis of variance and Tukey post hoc test. Significance was defined as p>0.05. Significant increase of creatinine (p>0.01), urea (p>0.001), BUN (p>0.001), and uric acid (p>0.001) and significant decrease of albumin (p>0.01) and sodium (p>0.01) was observed in the gentamicin-induced renal damage group in comparison to the normal control group. Treatment with simvastatin (20 mg/kg) in the animals suffering from kidney damage caused significant decrease of creatinine (p>0.01), urea (p>0.01), BUN (p>0.001) and uric acid levels (p>0.001) and significant increase in albumin (p>0.05) and sodium levels (p>0.01). The results of the present research indicate that simvastatin could improve kidney damage due to consumption of gentamicin in rats.

Environmental pollution and occupational exposure to toxic metals, such as mercury, cadmium and lead, causes chronic and malignant diseases with significant complications in the majority of body tissues. Increased production of free radicals and reduced antioxidant activity is considered as the main factor for the incidence of lesions resulting from cadmium poisoning. The aim of this study was to evaluate the effect of clove essential oil and vitamin C on growth performance, intestinal villi morphology and immune response to Newcastle live vaccine of Japanese quails challenged with cadmium. A total of 240 one-day old quails were divided into 8 groups with 30 quails in each group (3 replicates with 10 birds). Groups 1 and 8 received basal diet; groups 2 and 7 basal diet + 500 ppm vitamin C in the diet; groups 3 and 5 received basal diet + 150 mg/kg of the diet clove essential oil; and groups 4 and 6 received basal diet + 450 mg/kg of the diet clove essential oil. Cadmium chloride (40 ppm) was added to the drinking water of groups 1, 2, 3 and 4 during the experimental period (days 7-35). On day 21, 9 blood samples were collected from each group and segments of duodenum, jejunum and ileum of 9 quails from each group were isolated and sampled on day 35. The results indicated that groups 6 and 7 had significantly (p<0.05) greater body weight, villi dimensions and absorptive surface than the control group. Also groups 2, 4 and 8 had a significant increase of the intestinal villi dimensions and absorptive surface in different segments of the intestine compared to group 1 (p<0.05). In conclusion, the results of the present study showed that adding vitamin C and clove essential oil to the diet of Japanese quails had positive effects on growth parameters and intestinal villi absorptive surface and also alleviated the negative effects of cadmium on body weight and intestinal villi absorptive surface in these birds.

Marek,s disease (MD) is one of the major immunosuppressive diseases in the poultry breeding industry, which can cause lymphoproliferative lesions in various visceral organs. Early identification of the disease in laying farms will prevent the cost of treatment and allows prompt decision-making on control measures and bio-security against the disease. In this respect, for detection of Marek,s disease virus (MDV) in nodular lesions of visceral organs of backyard fowls and tissue tropism of MDV, 50 samples were collected from suspected cases of Marek,s disease (MD). The samples were prepared from various tissues with and without gross nodular lesions. After DNA extraction from tissue samples, a 314-bp fragment with specific primers was amplified using PCR test to identify the infected cases and the tissue distribution of the antigen-A gene. In addition, 434 bp fragment of tandem repeat were also amplified by the use of a specific primer for the purpose of differentiation of pathogenic strains from non-pathogens. The results showed that in all cases infected with the MDV, in the tumorigenic stage, the gene that codes for antigen A can be detected in tissues with and without lesions. In addition, all positive samples belong to pathogenic strains. Therefore, in the tumorigenic stage of the MD, in spite of the presence or absence of macroscopic symptoms in the carcass of birds, the antigen-A gene of MDV can be detectd in all tissues.

Parasitic infestation of breeding sheep can cause weight loss, production loss and condemnation of edible organs at slaughter. This study was designed to evaluate gastrointestinal parasitic infections in sheep of Sistan region. Fecal samples from 395 sheep were collected randomly. Coordinates of the sampling locations were recorded using a GPS device. Fecal tests were conducted using the Clayton-Lane floatation method. In this study only cestode eggs of the genus Moniezia and protozoan oocysts of the genus Eimeria were found in the faeces. Prevalence of Moniezia was 21 percent (83 cases) and prevalence of Eimeria was 39 percent (154 cases). There was no nematode or trematode eggs in the selected fecal samples. Chi-square test showed that there was no significant difference between the prevalence of Moniezia in cold and warm seasons but the prevalence of Eimeria in the warm season was significantly greater than the cold season (p=0.008). The results showed that gastrointestinal parasitic fauna of sheep in Sistan region is different from other regions of the country. This may be due to hot and dry weather of Sistan. In addition, the 120 days' winds of Sistan displace a large volume of soil in this region that can cause scattering of sheep stool in the desert, preventing completion of the life cycle of parasites.

Carbamazepine is used as an anticonvulsant drug in the treatment of simple slight convulsion and generalized tonic-clonic, trigeminal neuralgia, and also as preventive agent in manic depressive. Carbamazepine reduces synaptic transmission by prolonging the inactivity of cellular sodium-potassium pump. Considering the clinical use of carbamazepine, the current study aimed to evaluate its cardiac effects in dogs. In this experimental-interventional study, fourteen native 1.5-2 years old female mixed breed dogs were procured and after laboratory testing and physical examination to ensure their general health status, they were divided into treatment and control groups (7 dogs in each group). On day zero, before drug administration, the electrocardiogram, echocardiogram and blood pressure was recorded. Both groups were maintained in the same conditions and carbamazepine was given orally to the treatment group for 7 days (with a dose of 8 mg/kg). After completing the administration period, the electrocardiogram, echocardiogram and blood pressure was obtained once again and the data were analyzed by one-way ANOVA. Blood pressure was significantly reduced in the treatment group (p<0.05). Significant changes were also induced by carbamazepine in the dogs’ electrocardiogram and echocardiogram (p<0.05). According to the results of the current study, it was found that carbamazepine could decrease blood pressure and induce notable alterations in the electrocardiogram and echocardiogram of dogs.

Considering that the horse breeding industry is the fourth largest source of income generation in the world, and due to the diversity of species of horses in the world and the necessity of purity determination amongst breeders and horse owners, the importance of laboratory research in this regard is justified. According to past research, carried out sporadically in the country and abroad, there is a vacuum in the study of Iranian horses in terms of the diversity of genetic markers such as STR. The present study investigated short tandem repeat (STR) and allele frequency of 50 Arab horses using four loci (VHL20, AHT4, HTG4 and HMS7) recommended by the International Society for Animal Genetics (ISAG). For this purpose, genomic DNA was extracted from whole blood using the Miller procedure and amplified by Multiplex PCR with fluorescent primers.  The results indicated the presence of high genetic variability among the population of Arab horses. The number of alleles observed for each locus ranged from 6 to 9 with tAHT4 and VHL20 markers having the highest number of alleles with 9 alleles, and HTG4, with the highest heterozygosity. The HMS7 site had the lowest number of alleles among the sites examined with 7 alleles, and the VHL20 site had the lowest heterozygosity. The results of this study indicate a high frequency of genetic variation among the population of Arab horses.

Salmonellosis is one of the most important zoonotic diseases. Using a variety of antibiotics is the key to reducing the incidence and mortality associated with Salmonella infections. However, incorrect use of antibiotics in commercial poultry farms may lead to the emergence of antibiotic resistance and consequently inadequate antimicrobial drugs. Also, the transfer of antibiotic-resistant strains to humans through the food chain could also be a public health threat. Therefore, the aim of this study was to determine the serogroup and antibiotic resistance pattern in Salmonella isolates from 8 commercial laying herds in Tabriz area. For this purpose, after isolation of Salmonella from different samples, the isolates were tested by specific antisera and then their antibiotic resistance pattern was determined using disk diffusion method (based on Kirby-Bauer method) against the 6 types of antibiotics used in the poultry industry in Iran (Enrofloxacin, Fluorphenicol, Fosphomycin, Lincospectin, Soltream and Doxycycline) and 6 types of antibiotics used  in humans (Gentamicin, Co-amoxiclav, Ciprofloxacin, Cefalexin, Cefotaxime and Ceftriaxone). From the 96 tested samples, 16 isolates of Salmonella were identified with 10 isolates belonging to serogroup D but 6 isolates did not belong to any of the tested serogroups. Also, all isolates were sensitive to Gentamycin and Fosfomycin and the highest resistance was observed towards Doxycycline with an abundance of 83.35%. The relatively high prevalence of drug resistance among Salmonella isolates from commercial laying poultry showed that antibiotics should be administered with more caution and care.