Iranian Journal of Veterinary Medicine
Year:2010 | Volume:4 | Issue:1|Papers Count:16

Tetracyclines (TCs)are broad-spectrum antibiotics that are used widely in veterinary medicine. The present study was carried out to trace the residues of oxytetracycline (OTC) and tetracycline (TC) in pasteurized milk that is marketed in Tehran with the use of a High Performance Liquid Chromatography (HPLC). Ninety milk samples were collected during five sequential days from the products of six major dairy companies. OTC and TC residues were extracted and quantified by an HPLC method with an ultraviolet radiation detector.TC residues were found in seven (7.8%) milk samples. The OTC and TC in almost all samples were lower than 100 ppb (parts per billion), which is the maximum residue level advised. However, the total residue of OTC and TC in one milk sample was 138.8 ppb. In conclusion, due to the presence of a significant amount of TC residues in a number of milk samples, more studies and further supervision of the quality of milk products are required.

It is not known whether the instincts of wild horses have remained strong during their centuries of domestication. Knowledge of this matter would give riders the opportunity to know more about the behavior of horses and consequently about safety for both horses and riders. In this current research, we studied the behavior of fifteen Caspian miniature horses of different ages and sexes using stimuli from predators under standardized conditions. We explored whether olfactory (lion feces) or auditory (lion roars) stimuli affected horses to a greater extent. The test arena was an appropriately equipped grass paddock, in which horses spent between 5 and 8 min. The experiments were designed to investigate behavioral responses in locomotive activity (alertness, standing, walking, trotting, exploration and other), eliminatory behavior (defecation, urination) and physiological responses (heart rates before and after the predator stimuli) of horses to novel auditory and olfactory stimuli. In the olfactory experiment, we found that the horses showed significantly more behavioral reactions compared to the control experiment (where horses were not exposed to any stimuli), the only behavioral reaction the horses did not show was flight reaction. Additionally, heart rate was significantly increased after olfactory stimuli compared to auditory stimuli. In the auditory experiment, we found that horses showed more behavioral reactions in response to the roar of the lion compared to the olfactory stimulus, including flight reactions. We concluded that the auditory stimuli caused significantly higher heart rate responses when compared to the olfactory stimuli.

Two hundred and fifty day-old broiler chickens were housed in a high altitude farm and divided in two experimental groups (cold-exposed and control). At the age on and 4 d, the cold-exposed chickens were exposed to 15oC for 3 h, while the control birds were reared under normal condition. During the period between 14 and 28 days, both groups of chickens were exposed to a low environmental temperature. For hormonal analyses, blood samples were taken at days three and four (before and after cold exposure), and followed by samples taken at seven, 14, 28 and 42 days. The mean plasma corticosterone level was significantly higher in cold chickens, who were first exposed to cold temperature at days three and four of age. However, this result was reversed at day 28 during the second cold challenge. Cold-exposed birds showed significantly higher T3 levels compared to control chickens at day three after exposure to cold temperatures. During the second cold exposure (day 28), the T3level was significantly lower in cold chickens compared to control chickens. At days three (after cold exposure) and four (before cold exposure), the concentrations of T4 were significantly lower in cold-exposed chickens compared to the control chickens. Such hormonal responses coincided with a marked reduction of ascites mortality in the early cold-exposed chickens compared with control chickens. In the present study, repeated cold exposure resulted in a moderate response; lower corticosterone and TJ levels resulted from the second cold exposure than from the first one alone. It can be concluded that early cold exposure improves the thermotolerance of broiler chickens at a later age, which consequently leads to an adaptation that reduces the incidence of the ascites syndrome.

In the present study, the effects of intracerebroventricular (ICV) injections of histamine, chlorpheniramine (H)-receptor antagonist) and ranitidine (Hz-receptor antagonist) were investigated on visceral nociception induced by an intraperitoneal (IP) injection of acetic acid in rats. The latency time to the beginning of the first abdominal wall contraction (the first writhe) was recorded and the number of writhes was counted for 1h after the IP injection of acetic acid (1 ml, 1%).All treatments (histamine: 2.5-80 mg, chlorpheniramine and ranitidine: 5-80 mg) did not influence the latency time to the beginning of the first writhe significantly except for the 40 mg dose of histamine, which significantly increased the latency time (p<0.05). Doses of histamine of 10 and 40 mg and doses of chlorpheniramine and ranitidine of 20 and 80 mg significantly decreased the number of writhes (p<0.05). Pretreatments with chlorpheniramine or ranitidine at the dose of 80 mg significantly prevented histamine-induced (40 mg) antinociception (p<0.05). These results indicate that brain histamine may mediate the perception of visceral antinociception through both centralH) andHzreceptors.

Infectious bronchitis virus (IBV) is an acute and contagious viral disease of poultry that affects different systems, including the respiratory tract in particular. IBV causes major economic losses in the poultry industry globally. Due to antigenic variation of the causative agent, control of the disease is difficult. To control the disease, many vaccines that belong to different serotypes are being used in many countries, including Iran. In the present study, the S1genes of six different IBV vaccines were analyzed. The Sl genes of IBV vaccine strains were amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) and the resultant PCR products were purified. Purified PCR products were digested separately with the restriction endonuclease, Alui. The generated restriction endonuclease fragment length polymorphism (RFLP) patterns of the S1 gene of IBV vaccine strains were compared. The results showed that the construction of a library of RFLP patterns of the S1gene of vaccine strains in use is beneficial. The library has the potential for use as a quick and inexpensive method for determining the genotype of future outbreaks of IBV and also assesses the degree of their similarity to the strains for which vaccines exist.

A five-year-old male Dobennan pinscher with an oval-shaped mass in the left side of thorax, respiratory distress, and an impainnent of the use of the left forelimb was referred to the Faculty of Veterinary Medicine of Shahid Chamran University in Ahvaz. Radiographs were taken. The abnonnal mass was removed by radical surgery. Histopathological examination confirmed the occurrence of a well-differentiated canine osteosarcoma. The case was re-examined after approximately 15 months, which revealed a large mass in the left side and metastases in the right thoracic wall and lung. The decision was taken to euthanize the patient and a necropsy was perfonned. The recommended treatment for canine osteosarcoma is the removal of the primary tumor followed by adjuvant chemotherapy, but recurrence is common.

In the bone marrow, there are certain populations of stem cell sources with the capacity to differentiate into several different types of cells. Ideally, cell transplants would be readily obtainable, easy to expand and bank, and capable of surviving for sufficient periods of time. Bone marrow mesenchymal stem cells (BM-MSCs) possess all of these characteristics. One ofthe most important benefits in using BM-MSCs is the possibility of autologous therapy. Recently, numerous studies have evaluated strategies that attempt to promote axonal regeneration in central nervous system (CNS) injuries. Amongthese strategies, cell transplantation is considered to be the most effective way. The differentiation of stem cells into different neural lineages (such as astrocytes and neural like cells) before transplantation has a critical role in achieving the best results in studies of CNS injury. In this study, BM-MSCs were isolated from bone marrow Aspirates taken from the femurs of 103 live rats. The detection of BM –MSCs was performed with RT-PCR analysis, and they were then induced to differentiate into neuron-like cells in serum-withdrawal medium over a two week period using a multistep protocol. In addition to the morphological evaluation of differentiated cells, the process of neural differentiation was proven by immunocytochemical techniques using primary antibodies to Neuron Specific Enolase (NSE) to assess cell differentiation. PT-PCR analysis was performed for the evaluation of neural specific genes, which included NSE, MAP2, nestin, and b-tubulin. Morphological evaluations detect neuron like cells with longitudinal processes. Using RT- PCR and immunocytochemistry assays, neuron specific genes and proteins following treatment of cells in serum-withdrawal induction medium was expressed. This study showed' a simple and practical method for differentiating MSCs into neuron like cells, and feasibility of aspirate bone marrow from a liver at for autologous grafting.

Toxoplasmosis is a common and widespread infection in humans and many other species of warm-blooded animals. Toxoplasma gondii-derived heat shock protein 70 (Hsp70) may play an important role in the virulence of Toxoplasma gondii (T gondii). In the present study, T gondii Hsp70 was amplified by polymerase chain reaction (PCR) from the DNA of the T gondii tachyzoite RH strain through the use of specific primers with Xho 1 and Xbal restriction sites. The purified DNA fragment of the T gondii Hsp70 gene was subcloned into the Xhol and Xbal-digested eukaryotic expression vector, pcDNA3, and subsequently transformed into TOP 10 chemically competent cells. A 2004 base pair (bp) band of PCR product was observed on the 0.8% agarose gel. The cDNA was inserted into the pTZ57R/T vector and then subcloned successfully into the pcDNA3 eukaryotic expression plasmid vector. The sequence of this amplified gene showed up to 100% homology with the target gene according to the Genbank database (Accession no. U82281).

A serological survey was carried out to determine the prevalence rate of bovine viral diarrhea virus (BVDV) infections in water buffalo (Bubalus bubalis) in Ahvaz, which is the center of the Khouzestan province in Iran. For this purpose, blood samples were taken from 310 slaughtered buffaloes at the abattoir. Sera were tested via the serum neutralization test. Serum neutralization was performed by National Animal Diseases Laboratory (NADL), in order to isolate the genotype 1 strain of bovine viral diarrhea virus. The results indicate that 105 (33.9%) buffaloes had antibodies to BVDV. The prevalence of infection in females and males were 39.5% and 22.78%, respectively, and statistical analysis showed that this difference was significant. Although there was a non-significant difference between heifers and males, the difference between cows and bulls was highly significant.

Fluctuations in salinity impose stress on the physiology of the exposed fish population and can modify their structure. It has been noted that changes in blood characteristics and plasma levels serve as the primary link between environmental change and physiological response (McCormick, 2001). Ninety healthy adult Cyprinus carpio (c. carpio) were randomly divided into five groups and kept in salinities of 1 (control group), 3, 6, 9, 12 and 15 g/L The salinity was gradually increased by 3 g/L daily to final their concentrations. Fish were kept for 14 days after transference to the final salinity. Subsequently, plasma glucose, lactate, and protein content, as well as hematological parameters, were evaluated. The highest hematocrit (Hct), hemogloblin level (Hb), red blood cell count (REC), lactate, and glucose values were found fish kept in the highest salinity. The values of the white blood cell count (WBC) showed an initial increase in fish from the control group until a salinity of 9 g/L, but subsequently decreased at higher salinities. The plasma protein levels among the fish in different groups did not show a significant change. The results demonstrate that changes in blood parameters can be used as indices to monitor the effects of salinity on the physiology of C.carpio.

Toxocara cati is one of the most important and widespread of the helminth zoonosis. In the present study, helminthosis due to Toxocara cati in 55 stray cats in Tehran was studied by necropsy. In addition, two different diagnostic methods, including serological and coprological tests, for infection with this parasite were compared. The dot-ELISA assay used Toxocara cati crude antigens to evaluate the presence of serum antibodies against the mature nematode. The coprological sedimentation method was carried out to assess the output of eggs. In autopsied cats, 52.7% were infected with T. cati. Seropositive cases were detected in 53.8% of examined cats, whereas the prevalence in feces was 40%. The sensitivity and specificity for dot-ELISA method was 65.5% and 60.9% respectively. In sedimentation method the sensitivity was 69%, and the specificity was 92.3%. The positive and negative predictive values for dot-ELISA and sedimentation were 67.9%, 58.3% and 90.9%, 72.2% respectively. These results suggest that coprological methods for diagnostic and control programs of toxocariosis in cats are the optimal investigations.

Fasciola is a well-known parasite with a worldwide distribution and huge implications for the economic performance of domesticated herbivorous animals. It also caused deleterious effects on human health. It is prevalent in most parts of Iran, but especially in Gilan province. During 2005,445 fecal samples taken directly from the rectum of local cattle in three different regions of Gilan and were subjected to coprological examination using saturated zinc and sodium chloride solution. The sex, age and locality of cattle were recorded. Our findings revealed an overall infection rate of32% with the highest rate (55.2%) occurring in Talesh. No significant relationship was found between sex or age (P=0.65) and infection. Despite this, in contrast to the longheld assumption that adult cattle develops resistance to infection, our findings showed no difference between the rates of infection and the mean number of Egg Per Gram (EPG) in young and old cattle. The rate of infection in 5,820 slaughtered cattle showed that the fascioliasis is more prevalent among the animals examined in Talesh Region (P<0.01).Meanwhile, there was a direct relationship between the amount of rainfall and the rate of infection (r=0.98, P<0.01). The determination of Fasciola species in the liver of 70 native cattle revealed that 50 (71.4%) harbored F. gigantic, 14 (20%) had F. hepatica, and six (8.5%) had F. hepatica and F. gigantica. There fore, F.gigantica was the dominant species in the studied areas.