SCIENTIFIC-RESEARCH IRANIAN VETERINARY JOURNAL
Year:2013 | Volume:8 | Issue:4 (37)|Papers Count:14

Polymerase chain reaction (PCR) is a suitable method for detecting pathogenic agents and first step in this process is DNA extraction. DNA extraction enumerate as a long stage in molecular genetic researches that is longer than total PCR process in some cases. The aim of this research is use of direct PCR (without DNA extraction) for different typing of Clostridium perfringens. In this study direct PCR and also PCR by extracted DNA was implemented on the A, B, C and D types of Clostridium perfringens. For this purpose four pairs of specific primers that were complementary with parts of the genes encoding a, b, e and i toxins of this bacterium were used. In both direct PCR and PCR by extracted DNA, 196, 324 and 655 bp fragments were amplified that are dependent to a, b and e toxins respectively. Upshot different strains of this bacterium were identified based on amplified fragment length in PCR. The result showed that success of PCR is simple from colony directly and quality of created bands is the same in both methods. Therefore, use of this method is recommended because the direct PCR reduce time, steps and cost of PCR and provide possibility of testing many samples in shorter times provides.

Adsorbent clays have an excellent capacity of binding mycotoxins. This work assesses the potential of natural zeolite and bentonite for Aflatoxin M1 (AFM1) removal from milk and water. Artificially contaminated milk and water samples (with 50 and 500 ng/L AFM1) were contacted with 5 gr/L of sorbents, including zeolite powder, zeolite beads and bentonite powder. Amounts of residual AFM1, and also protein, fat and lactose content were determined in treated milks. Results showed that the adsorption of AFM1 on natural zeolite and bentonite varied from 63 to 100% based on the type of clays and AFM1 concentration. For zeolite powder, the adsorption treatment reduced the content of total protein. Adsorbent clays reduce the AFM1 content of milk by surface removal of them. These adsorbents do not destroy or inactivate the toxin and do not produce toxic residual. The extent of toxin removal depends on clay contact surface and by using proper clays; it is possible to reduce the AFM1 content of milk below the allowed level.

The aim of this study was to evaluate the effect of gonadectomy and chronic administration of testosterone propionate on histomorphometric structure of adrenal gland in male rabbits. Fifteen adult male rabbits were divided into control group (SO), orchidectomized group (Orx) and orchidectomized group treated with testosterone propionate (Orx- TP). Results showed that gonadectomy has no effect on the morphology and cellular arrangement of zona glomerulosa whereas the cells of the zona reticularis and zona fasciculata appear more voluminous and larger in the Orx group in comparison with the SO group. Gonadectomy resulted in a significant increase in absolute adrenal volume (P<0.05). If compared with SO group, only the increase in the volume of the zona fasciculata and zona reticularis was statistica lly significant (P<0.05). The mean volume of cells and their nuclei of Orx group, were higher than those in the SO group, but only the differences in zona reticularis and zona fasciculate were statistically significant (p<0.05). In all three regions, the number of cells and their distribution percentage of Orx group were not significantly different from those of SO group (P>0.05). Chronic TP treatment of Orx rabbits reversed these changes to the preorchidectomy state, so that none of the morphometric values of the Orx -TP group showed statistically significant differences in comparison with the SO group (P>0.05).

Foot and mouth disease is one of the most important contagious diseases of cloven-hoofed animals that may cause sever economic impacts. One of the important aspects of FMD is persistent infection that may occur after recovery from clinical form of disease or following exposure of vaccinated ruminants with live virus. In order to evaluate prevalence of persistent infection with FMD virus in buffalos, this study was conducted on 100 mature female buffalos slaughtered in Ahvaz abattoir in south-west of Iran. Samples were collected from pharyngeal secretions and dorsal soft palate tissue and tested by RT-PCR method. The results of this study showed 2 positive samples out of 100 collected samples which is the first report in Iran. Since buffalos are in close contact with other sensitive animals such as cattle and sheep, they may be a great hazardous to the spread disease in the region.

The notochord is a flexible and rod-shape structure that is typical characteristic of vertebrates and replaced mainly by intervertebral disc in mammals. Finally, the notochord disappears depend on animal species and take part in formation of intervertebral disc and nucleus pulposus. There is no report about the development of notochord in the water buffalo. This study was performed on 20 water buffalo embryos with CRL from 3.8 to 38 mm and estimated age from less than 30 days to 54.28 days. According to histological and developmental changes the embryos divided in 3 groups: group 1(8 embryos, CRL=7.06±0.16 mm, estimated age=less than one month), group 2 (5 embryos, CRL=14.5±0.15 mm, estimated age=35.38±1.34 days) and group 3 (7 embryos, CRL=28.5±0.75 mm, estimated age=51.64±4.29 days). For histological purposes 0.5 cm from lumbar part of the vertebral column was sectioned transversally fixed in 10% formalin and serial sections prepared at 5-6 mm thickness. The sections stained by H& E and studied by light microscope. The results showed that maximum development and regression of the fetal notochord was occurred on embryos with CRL=8.9 mm and 38 mm (less than one month old and 55 days), respectively. The notochord consists mainly of mesenchymal cells with round nucleolus, clear nucleolus and light cytoplasm. However, with increasing age of embryo, the number of notochordal cells gradually decreased and finally disappeared. At the end of embryonic period, the notochord structure changed and limited to small round area with thick wall that was without any cells in the center of the intervertebral disc named nucleus pulposus. Additionally, our finding showed that formation and subsequent regression of notochord is very similar with reports about notochord of cattle. On the basis of literature, the maximum development and growth of notochord is on 40-50 days in human. However, our results revealed that the regression of the notochord in water buffalo embryos occurred with 51.64±4.29 days old. So, it is concluded that regression of the notochord and formation of intervertebral disc in the water buffalo embryos is very similar with other domestic animals and especially cattle.

Cyanide is a potent and ubiquitous toxicant. Acute cyanide intoxication could be fatal due to inhibition of respiratory chain. Moreover various health disorders and histopahological lesions have been reported following chronic cyanide poisoning in humans and animals. The aim of the current study was to determine the effects of choronic cyanide exposure on enzyme activities of aspartate aminotransferase (AST), alanine aminotransferase(ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and rhodanese in some tissues of common carp. In this study 75 healthy common carp, weighing approximately 60 g were divided randomly into three groups of 25 each. These three groups were maintained in similar environmental and nutritional conditions and were exposed to 0.0, 0.2 and 0.4 mg/L potassium cyanide for 14 days, respectively. At the end of each exposure, enzyme activities in prepared tissue homogenates of liver, kidney, gill, and brain were determined using validated spectrophotometric methods. Cyanide exposoure (0.2 mg/L) caused a significant (p<0.05) increase in AST and LDH activities in the liver as compared with the normal control group. Additionally, cyanide exposure (0.4 mg/L) caused a significant increase in AST, LDH and rhodanese activities in the liver, AST activity in the brain and LDH activity in the kidney as compared to control group (p<0.05). The observed alterations in the activity of tissue enzymes reflect the metabolic disturbances due to chronic cyanide intoxication in studied organs.

Diabetes mellitus is a disorder of carbohydrate, lipid and protein metabolism which causes a considerable disorder on centeral peripheral nervous system. It has been reported that Urtica dioica has protective effects on diabetic disorders. The present study was undertaken to evaluate the protective effect of Urtica dioica on histomorphometrical structure of sciatic nerve in diabetic rat. 15 adult male rats (220-250grs) were divided into 3 groups; control, diabetic and diabetic which received Urtica dioica (50mg/kg) orally. Diabetes was induced by IP injection of 60 mg/kg of STZ. After six weeks, samples were taken from anterior, middle and posterior parts of sciatic nerve. 5-6 m sections were made by embedding paraffin method and stained by H& E. The results showed that the diameter of sciatic nerve axon and myline were decreased in diabetic rats. These changes were improved by administration of Utrica dioica.

In this study the growth stimulatory effects and resistance against environmental stressors (density, transport and bacterial infection) of oral administration of Levamizol, Ergosan and Vitamin C as well as extracts of Echinaeca, Aloe vera, viscum albom and Nigella sativa, in barbus barbulus were investigated. A total of 1200 fish (weighing 1.9±0.12 g) were randomly divided into 8 groups in triplicates for each immunostimulant plus to control group. The fish fed mixed with immunostimulants and each treatment was fed with their specific food for 6 weeks. Mortality rate during the study, initial and final weight and food consumption were recorded in each group. At the end of the study the density and transport stress tests were carried on and all treatments challenged with Aeromonas hydrophila. Results showed that growth factors including Specific growth rate, growth percentage and growth conversion rate significantly improved in all treatments except Nigella sativa compare to control (P<0.05). Post challenge mortality and density stress mortality significantly decreased in all treatments except Vitamin C and Nigella sativa groups compare to control (P<0.05). No significant changes were seen in mortality rate during treatment period and results of transport stress test (P>0.05). It can be concluded that the extracts of Echinacea purpurea and Viscum albom have stimulatory effects on growth and resistance against bacterial infection and density stress in Barbus barbulus and it is comparable with the effects of approved fish immunostimulants such as Ergosan, Levamizol and Vitamin C.

Ornithobacterium rhinotracheale (ORT) has been identified as one of the emerging respiratory bacterial pathogens in turkey and chicken flocks. The aim of this study was the analysis of 16S ribosomal RNA nucleotide sequences of some isolates from Alborz province chicken flocks. For this purpose, 10 ORT isolated and identified by culture method from commercial chicken flocks of Alborz province were selected. After DNA extraction using phenol-chloroform method, all samples were tested by specific PCR for ORT identification. The second PCR for amplification of 16S rRNA complete gene was set-up and then about 1450-bp bands were sequenced. Multiple alignment and phylogenic analysis of DNA sequences were performed with Bioedit and MEGA programs. Phylogenetic analysis of ORT isolated from Alborz province (6 of broiler origin, 3 of layer origin and 1 of broiler breeder origin) and 63 ORT sequences obtained from Gen bank from all around the world showed high genetic similarity (98.6%-100%) among them. The 16S rRNA sequence of 73 ORT sequences were grouped into three genetic clusters. The Alborz isolates showed 100% similarity. These 10 isolates showed the most homology with ORT isolated from USA, Russia and Taiwan. Overall, these results revealed the same molecular structure and high homology among ORT isolates from Alborz province.

Information about the infective dose of an infectious agent is required for experimental trials of vaccine developed against that agent. Despite the versatility of Trueperella pyogenes as an agent of disease in animals, little is known about its infective dose for domestic animals. In order to determine the infective dose of T. pyogenes in sheep, this study was carried out. For this purpose four groups (A to D) of 2-3 months lambs (three lambs per group), were intravenously infected with 107, 108, 109 and 1010 cfu of T. pyogenes, respectively. The fifth group of lambs (group E) was injected with sterile phosphate buffered saline (PBS) and served as control. Blood samples were taken daily from all animals for bacterial cultivation till 10 days post infection. Clinical signs were recorded and all animals were euthanized ten days post infection, autopsy were done and samples (from liver, spleen, mesenteric lymph  nodes, heart and lung), were collected for bacteriological and histopathological examinations. The results showed that although septicemia is not a constant criterion of experimental intravenous T. pyogenes infections, but it can lead to a consistent pattern of liver infection, ten days after inoculation. Post-mortem examinations revealed that all animals of group D had developed typical liver infection. No liver infection was observed in other lambs. Fifty percent lamb infective dose of the bacterium was calculated to be 3.162×109 cfu. This finding is the basis for experimental trials of vaccine developed against the bacterium.

Regarding the possibility of streptococcosis prevalence in Iran rainbow trout culture farming and great damage on the aquaculture industry, in this research, possibility of indirect use of silver zeolite as granule (100, 150 and 200 gr) and polyamide filaments (100 gr) in water filtration of culture system of rainbow trout fry was studied to control Streptococcus iniae. After confidence of inhibitory power of silver zeolite against mentioned bacteria via in vitro experiments, minimum inhibitory concentration (MIC), zone of inhibition test and test tube test, the granular and filamentous filter media containing Zeomic was used in filters. In next stage, for in vivo experiments, S. iniae (105 cell/ml) was inoculated to the water and efficacy of filters in inhibition of bacteria was evaluated by total count of bacteria (microbiological test), mortality rate, clinical signs and also kidney and spleen culture. Based on the results, the minimum inhibitory concentration of silver zeolite on the growth of S. iniae Aynyayy 250 mg/ml was calculated. The results indicated significant difference in decreasing of water bacteria, fish mortality and disease symptoms in treatments containing silver compounds compare to controls. In total, between tested filter media in this study, polyamide filaments containing silver zeolite have the highest efficacy for the use in water filtration system to control S. iniae with reduction of bacteria from 5.48±0.01 log to 3.5±0.17 log. According to the results, it seems that indirect use of studied silver compounds as filter application have the sufficient potential to control bacterial infection and disease prevention in culture system of rainbow trout. Other side effects of these materials on aquatic organism needs more research in future.

The effects sub-lethal concentrations of diazinon on some enzymes parameters of kutum (Rutilus frisii kutum, Kamensky, 1901) weighing 613.33 g±157.06 g were studied under static water quality conditions at 150C±20C in winter and spring 2009. The first test was conducted to determine the effects of acute toxicity (LC5096 h) of the diazinon (emulsion 60%) on kutum male brood stocks. For this purpose, 4 treatments were used to test toxicity; each treatment was repeated in 3 tanks with 9 fish per treatment and with 180 litres watercapacity. After obtaining the final results, the data were analysed statistically with Probit version 1.5, and we determined the LC10, LC50 and LC90 values at 24 hours, 48 hours, 72 hours and 96 hours; the maximum allowable concentration value (LC5096 h divided by 10); and the degree of toxicity. The second stage of testing consists of four treatments: LC0= 0 as experimental treatment, treatment A with a concentration of LC1=0.107 mg/L, treatment B with concentration of LC5=0.157 mg/L, treatment C with concentration of MAC value= 0.04 mg/L. Male brood stocks of kutum were treated with these concentrations for 45 days. Experiments were carried out under static conditions based on the standard TRC, 1984 method over 45 days. Our results showed that long-term exposure to diazinon causes a decrease in the lactate dehydrogenase (LDH) and cholinesterase (CHeS). In addition, diazinon also causes an increase in aspartate aminotransferase (AST) and alkaline phosphatase (ALP) (P<0.05). The results indicated that long-term exposure to low concentrations of diazinon causes changes in some serum enzymes of R. frisii male brood stocks.