Journal of Veterinary Research
Year:2009 | Volume:64 | Issue:2|Papers Count:15

aroA is an important gene which produces aromatic amino acids essential for bacterial life. The sequence of this gene was shown to be different in bacteria, so the purpose of this study was sequencing of aroA gene in native E. coli 078: K80 to determine the putative differences between this strain and other E. coli 078: K80 strains in gene bank. PCR was used to amplify aroA gene in native E. coli 078: K80. The amplified 1.206 kb PCR product was extracted from Agaros gel, ligated in pTZ57R and sequenced. Blast analysis showed that aroA sequence in native E. coli is different from already submitted homolog gene in Gene Bank. Two amino acids were shown to be different from those already found in other E. coli strains. These different amino acids are Isoleucine and Glycine instead of 39thThreonine and 240th Glutamic acid, respectively. Knowing these differences are important for doing molecular techniques, designing primers and future studies.

Cryptosporidium is a ubiquitous enteric protozoan parasite that infects a wide range of vertebrate hosts. In humans and many other mammals, cryptosporidium is recognized as a significant pathogen primarily as a cause of acute, severe diarrhea illness. At this investigation animal samples (stool) were collected from 708 heads of lambs (in the beginning of the birth to three months) and 713 heads of calves (in the beginning of the birth to six months) in spring, summer, autumn and winter seasons at amol city in 1374. the samples were delaminated after staining using modified zihil- nelson technique. Results showed, 29 samples of lambs (4.09%) and 28 samples of calves (3.92%) were positive. Also in winter season infestation rate was higher than the other seasons (4.65%). whereas infestation rate in animals without clinical signs is high, so this subject is a important problems for public health.

In order to evaluate the possible immunosuppressive effects of coccidial infection on Cell Mediated Immunity (CMI) of broiler chickens, 640 Ross male day old broiler chicks were randomly divided into 4 equal groups of 160 (each consist of 4 replicates of 40). The negative control group remained unchallenged, while the other three groups challenged with 3 different levels of high, medium and low doses of mixed inoculums of E.acervulina and E.maxima at 15 days of age. For the assessment of CMI, Macrophage Migration Inhibition (MIF) test was performed. For this purpose blood samples were collected at 15, 22, 36 days of age. No significant difference was observed among MIF of different groups at 15 days of age (p> 0.05). At 22 and 36 days of age a significant difference observed among MIF of high dose and control groups (p<0.05). According to the results, it can be concluded that severe coccidial infection may compromise specific CMI activity in broilers.

Salmonella Enteritidis (SE) is frequently isolated from poultry and humans. Chicken meat and egg are two important sources of SE infection for humans. This study was conducted to detect the SE infection in Iranian poultry farms using serological methods. Anumber of 8208 serum samples were provided from 171 poultry flocks (pullet, commercial layer, broiler breeder, layer breeder, grandparent breeder, and broiler) and were analyzed by rapid slide agglutination test (RSA) and ELISA. All samples were negative in RSA but ~ 45%1 of samples (from 112 flocks) contained anti-SE antibody in ELISA. The titres ranged 0.476-0.590, which were at low level and showed the value of ELISA vs. RSA. The results indicated that the poultry flocks had been infected with SE at least once during the course of production. This is the first comprehensive study, at this sample size, in Iran regarding the serologic profile of SE in poultry flocks and its findings are very important for poultry industry and the control strategy for SE infection.

Diet components are one of the determination factors for changing of morphology of small intestines which lead to a change in digestien and absorption of nutritiond subs tonces. To study the histomorphometric changes of small intestine due to hull-less barley food diets in poultry, 20, Of 70 weeks old healthy Road Island Red cocks were selected and divided equally into 2 experimental groups and fed with hull less barley, and commonly usual diet (control). Feeding was gradually and by adding the experimental food to the commonly used diet through one week. At the end of the week, all animals starved for 24 hrs and then fed with experimental diets for following week. At the end all animals were weighted and sacrificed after 24 hrs of starving. excreta viscosity and crude diet energy, crude excreta energy and metabolisable energy were measured and the data were analyzed using Duncan method. Transverse sections from small intestine were successively cut with 2cm intervals and fixed with 10% buffered formalin. Routine histological laboratory methods were used and sections were studied under light microscope. Heights and width of the villi and dept of the crypts and goblet cells number were measured. Data's were statistically analyzed by ANOVA test. Results showed: increasing in viscosity, increasing the villus heights (p<0.001), villus width (p=0.002) and crypt depth (p<0.001) and number of goblet cells (p<0.001) in jejunum, decreasing in height of the villi (p<0.001) and increasing in crypt dept (p<0.001) and goblet cells number (p=0.04) in the duodenum and increasing of the crypt dept (p=0.004) in the ileum were observed respected to the control.

Due the fact that during estrus cycle the genital organs are affected by female reproductive hormones, the physiologic changes more likely will reflected in structural alterations of genital organs. For determination of histological changes during estrus cycle, 20 genital organs from 4-8 years old buffalos were collected from abattoir and 10 specimens were appointed to each phases of estrus cycle. The tissues were stained with H&E, PAS, Verhoeff, Toluidine blue and VanGeisson's methods, respectively for general histological study, carbohydrate, elastic fibers, mast cells, and collagen fibers. Mucosal epithelium was simple columnar and some cells were ciliated and some others recognized by extensive and clear cytoplasm. Epithelium in follicular phase contained PAS positive granules more than the leuteal phase. Collagen fibers revealed more in deep region of mucosa-sub mucosa and between bundles of muscles. Elastic fibers were observed in connective tissue of tunica muscular is and around of blood vessels. Mast cells were observed in mucosa-sub mucosa and tunica muscularis. We conclude that; the epithelium of uterine cervix in follicular phase of estrus cycles has secretary activity. The structural firmness and solidity of this organ most probably is due to presence of collagen fibers in mucosa- sub mucosa layers. More likely, the mast cells involving in histological changes of the cervix during estrus cycle.

Zataria multiflora essential oil, hydrogen peroxide (H2O2) and malachite green (MG) were used to assess their effects on rainbow trout egg hatchability and survival of larvae up to 1-1.2 g body weight using spring water at 12.5°C, dissolved oxygen 8-9 mg/L, carbon dioxide 7±2 mg/L, ammunia <0.01 and total hardness about 170 mg/L. Zataria was used at 70 mg/L for 30 minutes per day, at 500 mg/L for 35 minutes per day with a reducing in the time treatment to 5 minutes during 70-140 degree-day and MG as the positive control at 2mg/L for 20 minutes per day. Normal control without any treatment was also included. Each treatment trial was provided in three replicates. The treatment trials started 36 hours post-incubation and were continued until the eyed-egg stage. The obtained results showed that the mortality level in normal control was significantly higher than other groups (p<0.05). Also, the mortality rate in eggs treated with Zataria was significantly higher than both MG and H2O2 groups (p<0.05). No significant different was seen between MG and H2O2 groups until the eyed-egg stage (p>0.05). Level of mortality in egg treated with Zataria was significantly higher than MG from eyed egg stage until the hatching stage (p<0.05). In addition, the mortality rate of the produced larvae kept to 1-1.2 g body weight was significantly higher in both Zataria group and normal control groups than other two groups (p<0.05), while no significant difference was seen in weight of the produced larvae among all examined groups (p>0.05). The results showed that use of Zataria at 70 mg/L is incomparable with H2O2 and MG, although it is able to significantly improve the survival rate of rainbow trout eggs and larvae during incubation period.

Progestagens have been used in order to control follide wave dynamics in camelids, however, the results are contra versial. The purpose of this study was to investigate the effect of single norgestomet implant on ovarian follicle development in Bactrian camel. Bactrian camels (n=8; 6-14 years old) were assigned randomly to two groups. Norgestomet treated group (n=4) received one implant of norgestomet under the skin of ear for 10 days (Day 0= Day of implant insertion). Camels in Control group (n=4) did not receive any treatment. Daily ultrasound examination using trans-rectal linear probe was conducted to determine ovarian follicle status. Mature follicle was defined as a growing follicle at the size of 13-17mm in diameter. In both groups, there was a female with a persistent follicle throughout the experiment and a new emergence of follicle wave on Day 6-7 of the experiment. The latter follicle did not reach mature size on Day 10 of experiment. In both groups, there was a female with growing follicle during the experiment that became at the range of mature size at the termination of study. In both groups, there was a female with a regressing follicle throughout the experiment and a growing follicle which become mature during 10 days of treatment. One female in Control group had a persistent follicle throughout the experiment and a new emergence on Day 9. One female in Norgestomet treated group, had a persistent follicle during experiment and a growing follicle that ovulated spontaneously between Days 9 and 10 of experiment. In conclusion, single Norgestomet implant for 10 days does not regulate ovarian follicle development in Bactrian camel.

During 1387-86, total number of 120 blood samples gathered from sheep with bluetongue-like clinical sign. The samples collected from seropositive regions. After separating serum, they were evaluated by competitive ELISA for detecting Ab against VP7 antigen. The full length of S7 gene (1156 bp) amplified by one step RT-PCR. In this method two sets specific primers, targeting 3? and 5?ends of S7 segment, were applied. For confirmation of PCR products in first amplification, nested-PCR was used. By using internal primers the most samples which displayed weak S7 band, produced a sharp and specific internal band (769 bp). By this method the sensitivity of virus detection dramatically increased .Among the blood samples, the number of BTV serogroup positive, nPCR positive, both BTV serogroup and nPCR positive and both BTV serogroup and nPCR negative cases were determined, 41 (34.8%), 23(19.2%), 12(10%) and 56( 46.6%) respectively. This is the first report about using RT-PCR for BTV detection in Iran. RT-PCR and nPCR molecular technique can be used as a very sensitive and reliable method for BTV detection in blood samples.

Bovine leukosis virus (BLV) is a retrovirus that primarily affects lymphoid tissue of cattle. To determine the seroprevalence of Enzootic Bovine Leukosis Virus infection and its effects on some clinical, hematological and flow cytometric indications, this study was conducted on 197 Holstein cattle slaughtered in an abattoir in Tehran province. ELISA gp51 test of the obtained serums of the animals showed that the mean of infection rates was 22.3%. Age arrangement of the relative frequencies of the infection showed a significant correlation between EBLV infection and age increasing (0.001<p<0.005). There was a significant difference between the infection rates in cattle with any clinical problems or macroscopic pathological lesions and in apparently normal animals (0.001 <p<0.005). There weren't any significant correlation between EBLV infection and sex and body condition score. With omitting the animals with any clinical problems or macroscopic pathological lesions and stressed ones, because of probability of the secondary changes in hematological indications of them, seropositive cattle had higher total leukocyte counts (0.01<p<0.05) and 10wer Tlymphocyte (CD4+) percentage (0.01<p<0.05) than seronegative cattle. In addition there was a positive correlation between the number of B-Iymphocyte (CD21+) and total leukocyte counts and lymphocyte percentage in seropositive cattle. Results of this study depicted high seroprevalence rate of Enzootic Bovine Leukosis Virus infection in the surveyed animals and lower CD4+-cells percentage in seropositive cattle than seronegative ones.

In order to determine the changes in serum and blood factors of rainbow trout following experimental infection with a pathogenic Aeromonas hydrophila, the cause of haemorrhagic septicemia in fish, three groups of rainbow trout (10 fish in each group) were injected intraperitoneally with 105, 106 and 107 of this bacteria respectively. The same number of fish in a control group was injected similarly with physiologic saline. After the appearance of clinical symptoms of haemorrhagic septicemia in fish, samples from skin mucus and blood of the fish were collected in order to determine lysozyme, anti- Aeromonas hydrophila immunoglobulins (measured by plate method and ELISA respectively), total white and red blood cells (WBC/RBC). Results showed that the lysozyme level in skin mucus and sera was significantly higher than the control group (p<0.05) while the immunoglobulin level of skin mucus of experimentally challenged fish was not significantly higher than that of control group except that of the group 2 and 3 of the experimental fish. WBC/RBC and hematocrit of the experimentally challenged rainbow trout were significantly higher than the control. Thus infection of rainbow trout with Aeromonas hydrophila increases the level of mucus and serum lysozyme, serum immunoglobulins, decreases RBC count and heamatocrit percentage.

  Early weanling and rearing of lambs on milk replacer is an important act to increasing flock productivity. Two experiments were carried out to compare the voluntary intake and nutrients digestibility ewe milk and commercial milk replacer and their feeding effects on the growth rate, feed intake and feed efficiency of suckling lambs. In experiment 1, eight lambs (two 4-lamb groups) at 31 to 34 days of age for 14 days and in experiment 2, thirty (two 15-lamb groups) Dalagh breed male lambs at 3±1 days of age for 90 days were reared in individual cages. In both the experiments, one group was fed with ewe milk and the other one with milk replacer. In experiment 1, the average of dry matter intake per Kg metabolic weight, dry matter, crude protein and crude fat digestibility of lambs which were fed with those which were fed with ewe milk and milk replacer had statistically significant difference (p< 0.01). In experiment 2, the average of daily weight gain, dry matter intake and feed efficiency of lambs fed with ewe milk and milk replacer did not have statistically significant differences (p>0.05). These experiments showed that suckling lambs fed with milk replacer in comparison with those fed with ewe milk; did not have any difference in growth, feed intake and feed efficiency.

Para-Influenza type 3 viruses are one of the most important respiratory system pathogens in cattle and buffalo which causes economical losses in cattle and buffalo raising industries. The aim of this study was to determine the PI3 frequency rate in buffalo calves in Khuzestan tropical area and detect the associated factors. One hundred two serum samples were obtained from buffalo calves in winter, spring and fall seasons of 2004 in Ahvaz city. Virus detection test, serum neutralizing test were performed on the samples. Statistical analysis was performed to show the relationship between disease and season, sex, and age. Among 102 samples fifty (49%) were positive for SN test. In spring 97.1%, in fall 7.5% and in winter 48.1% of cases was positive (p<0.001) a many cases 45% were male and 45.0% were male and 54.8% were female (p=0.441), age of 22.4% of cases were less than 12 months old and all the 12months old cases were positive (p<0.001). Prevalence of antibody against Para Influenza Type 3 was 49% in buffalo calves in Ahvaz as a tropical area. According to economic losses, administrators' more attentions and further researches are necessary.