مجله تحقیقات دامپزشکی ایران (دانشگاه شیراز)
سال:1384 | دوره: | شماره: |تعداد مقالات:16

The objectives of this experiment were to determine clinical and clinicopathological changes after proximal duodenal obstruction in sheep. Experiments were carried out on seven Iranian crossbred male sheep aged between 2-2.5 years old and weighing 45-50 kg. All operative procedures were performed under general anesthesia by intravenous infusion of sodium thiopental. A polyethylene tube reinforced with braided cotton tape was surgically placed around the duodenum in 5 to 6 cm caudal to the pylorus. Experimental observations commenced two days before tightening the ligatures and inducing obstruction. Measurements at this stage were considered as the control values. Clinical (appetite, urination, defecation, ruminal contractions, temperature, respiratory and heart rates) and clinicopathological indices (hematological parameters, concentrations of sodium, chloride, potassium, calcium, magnesium, inorganic phosphorous, urea nitrogen, creatinine and acid-base status in serum and urine) were determined simultaneously at 12 hrs intervals for 72 hrs. At the end of the experiment the animals became lethargic, anorexic, weak and dehydrated. Finally, six sheep died and one sheep was slaughtered. There were significant differences (P<0.05) between temperature, respiratory and heart rates of the control and experimental values. Moreover, significant increases (P<0.05) in hematocrit, RBC and WBC counts, hypokalemia (P<0.05), hypochloremia (P<0.05) and metabolic alkalosis were seen in experimental sheep. Significant increases (P<0.05) were detectable in serum concentrations of inorganic phosphorous, urea nitrogen and creatinine. There were significant declines (P<0.05) in urinary concentrations of sodium, potassium, chloride, magnesium, inorganic phosphorous, urea nitrogen and creatinine as well as a significant decrease (P<0.05) in urinary pH. In conclusion, proximal duodenal obstruction in sheep leads to clinical and clinicopathological changes which are important for diagnosis.

Infectious bronchitis virus (IBV) strain 4/91, prototype of the 793/B serogroup, was recently reported from Khouzestan province, Iran. Here we isolated and molecularly characterized a virus (Shiraz3. IBV) from broilers in Fars province. Following virus propagation in embryonated chicken eggs, we extracted total RNA containing the viral RNA from allantoic fluid. cDNA of the entire S1 and nucleocapsid (N) genes were generated with AMV-reverse transcriptase and genomic specific primers. The cDNA was subsequently amplified in a polymerase chain reaction (PCR). Digestion of the PCR products representing the entire S1 gene generated restriction fragments identical to those expected from strain 4/91 and differed from the control vaccine strain of H120. The N RT-PCR products representing the entire N genes of strains Shiraz3. IBV and H120 did not show any visible difference in size. The results presented here demonstrated that isolate Shiraz3. IBV is genetically closely related to strain 4/91 of IBV and can be differentiated from the IBV vaccine strain in Iran.

After parturition, the genital system is returning to its normal non-pregnant state. The reduction in the size of the genital tract is called involution. Involution of the ovine uterus after parturition was investigated following the intrauterine administration of oxytetracycline (2 gr). Under general anaesthesia and using strict asepsis the genital tract of ewes in 2nd month of gestation were exteriorised through a posterior midline laparatomy and four non-toxic split aluminium shots with different sizes were sutured to the wall of the uterine horns and internal os of the cervix (Radio-opaque markers method). Then, for assessment of uterine involution sequential radiographs were taken on the day of lambing and 3, 7, 14, 28 and 42 days after parturition. Three measurements (uterine body length, gravid and non-gravid horn diameter) were made on each of the radiographs. Involution of the uterine body length and gravid horn diameter were completed by about 28 days after parturition in sterile water treated (Control) group (n = 6) whereas completion of the non-gravid horn involution was significantly more rapid (by about 14 days after parturition) than gravid horn (P<0.05). The mean of the uterine body length, gravid and non-gravid horn diameter of oxytetracycline administered (treatment) ewes (n = 4) at any stages after parturition were non significantly higher than the control group (P>0.05). The mean of three measurements of the treatment (n = 4) group at the day 42 were similar to the control group at the day 14 after lambing. However, the present study demonstrates that treatment with intrauterine oxytetracycline may prolong involution of the reproductive tract of ewes after parturition.

Changes in some serum constituents and milk components and correlations between them, were used for defining the reason(s) of suboptimal milk composition in a dairy herd with a history of low protein tests during summers. Four groups of 8 adult Holsteins, 20-70, 70-110, 110-150 and 150-210 days in milk (DIM), under heat stress, with similar feeding and management practices were sampled for blood and milk four times on a 10 day interval. Milk volume, percentages of milk fat and protein and levels of serum glucose, total protein, albumin and BUN were determined. Milk volume decreased as DIM increased (P<0.05). Milk fat showed normal changes, but milk protein was similarly low in all groups (P>0.05), showing probable shortages in energy and/or protein intake. Serum parameters showed no significant differences among groups (P>0.05). Weak positive correlations were found between serum total protein and milk components after 150 DIM (maximum correlation with milk fat, r = 0.61). It is concluded that shortage in intake of energy and/or protein, which may result in lowered milk protein, may not be differentiated by measuring serum glucose, total protein, albumin and BUN and milk components. More detailed experiments on serum and milk are necessary for defining the problem properly.

After completion of the third stage of parturition and expulsion of the placenta, the uterus started to involuting until it reaches to normal size. The rate of uterine involution after parturition was studied in 6 healthy Makuii ewes. During second month of pregnancy the genital tract was exteriorized through a posterior midline laparatomy under general anesthesia and then four non-toxic split shots with different sizes were sutured on the serosal wall of the uterine body and horns. After parturition, the distance between markers was measured by sequential radiography. The mean length of the uterine body declined until 28 days after lambing but statistically maximum reduction was seen at about 14 days after parturition (P<0.05). Also, the mean diameter of gravid and non-gravid horn rapidly declined until 14 days postpartum (P<0.05) but reduction countinued until 42 days postpartum (P>0.05). The difference between the mean diameter of the gravid and non-gravid horn was not significant between days 14-42 (because of relatively small reduction in size). There were a high correlation between the measurements taken at the time of laparatomy and determined by radiography (4 days after surgery) for the mean length of uterine body (r = 0.89), the mean gravid horn diameter (r = 0.91) and non-gravid horn diameter (r = 0.79). In conclusion, after final statistical analysis of sequential radiographic views by using a repeated measurement analysis of variance, involution of the uterus in Makuii ewes was completed about 28 days postpartum for the uterine body and about 14 days for both the gravid and non-gravid horn. Radio-opaque marker is a useful method to study changes of the uterine size after parturition in live ewes.

Mycoplasmas were isolated from tracheal and air sac samples of the suspected flocks to have mycoplasmosis and cultured on Frey’s medium. Forward and reverse primers were selected on the basis of known sequences of Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) 16S rRNA genes. These primers successfully amplified a 780 bp fragment of the target DNA in MG. Restriction fragment length polymorphism (RFLP) by three restriction enzymes (REs), HpaI, HpaII, and MboI was performed for each PCR product. According to the RFLP results, 55 samples were detected as MG; no MS was detected. The PCR results were confirmed by sequencing of a selected amplicons. Results showed that PCR and RFLP are rapid and useful for diagnosis of both cultured as well as field samples of suspected flocks to have infection with MG. In addition, PCR could be performed with at least 100 CFU of MG per each PCR reaction.

This study was conducted to determine the histogenesis, growth and atresia of ovarian follicles in Makuii sheep fetuses at different developmental stages. Forty fetuses in four ages group of <35, 36–70, 71–100 and 101–150 intrauterine days old were taken for study. The fetuses were collected and preserved in 10% neutral buffered formalin solution. After recognition and harvesting of ovaries from fetuses, they were processed through routine paraffin embedding. Serial 5–7 µm thick sections were taken and stained with Hematoxylin-Eosin, Verhoeff, Van Gieson, Toluidne blue and PAS. Histologic and histomorphometric (point count) studies were adopted. In fetuses < 35 days old, the necrotic primordial germ cells (PGCs) were identified by pyknotic, condensed or karyolytic nuclei. In these fetuses, the undifferentiated gonads were recognized at the caudal aspects of the developing metanephrous kidneys. The healthy PGCs, were large with euchromatic nuclei, without any somatic cell surrounding them. In 36–70 days old fetuses, the germ cells were observed in clusters, which surrounded by simple squamous cells. The hilus cells were seen in mesovarium. In the 71–100 days old fetuses, primordial follicles were observed. In the 84 days old fetuses, primary follicles were seen for the first time. In the ovaries of 101–150 days old fetuses, the secondary follicles with zona pellucida and theca folliculi were seen. Tertiary follicles were not seen in any age groups. The mean number of germ cell population at 0.25 mm2 surface area of ovary, was the highest in 36–70 days old and lowest in 101–150 days old age group fetuses. It was revealed that in all age groups, the population of healthy follicles and/or germ cells is higher than population of atretic follicles and that there was significant difference (P<0.001) between them. There were significant (P<0.001) differences in the mean distribution of healthy follicles and or germ cells among all age groups. There were significant (P< 0.001) differences in atretic follicles among all age groups, except between 36–70 days old and 71–100 days old fetuses. We concluded that by increasing age, a decrease in population of healthy as well as atretic follicles in fetuses takes place. However, in all age groups, the population of the healthy follicle is greater than the population of atretic follicles.  

In this study antibiotic resistance pattern of E. coli and coagulase positive Staphylococcus aureus isolated from honey bees digestive tract of  Shahrekord apiaries were studied. From 45 isolated E. coli strains 35 isolates (77.77%) were resistant to one or more antibiotics. The most resistance pattern were to Erythromycin (77.77%), followed by 14 isolates to Nitrofurantoin (31.11%). From 22 isolations of S. aureus resistance to Penicillin and Erythromycin were 18 (85.71%) and 11 (50.00%) isolates, respectively. Number of isolations in two seasons (fall and spring) was statistically significant (P<0.005), but profile of the antibiotic resistant of the two bacteria in two seasons are not statistically significant.

Low-level pollution of aquatic ecosystems may decrease the fecundity of fish populations either indirectly via accumulation in the reproductive organs, or acting directly on sperm and ovum. The activity of highly active hydroxy steroid dehydrogenase (HSD) enzyme in fish sperm has been used as indicator of water contamination with zinc, cadmium or zinc + cadmium. Three groups of six male African catfish were fed from the sexually immature juvenile stage, with diet containing 1000 ppm zinc, cadmium or zinc + cadmium for 110 days and 20aHSD activity in milt of these fish were compared with six other control fish fed with normal diet. The 20aHSD enzyme activity was also measured in in vitro incubation of milt from six control fish with different concentrations (0, 0.1, 1, 3, 10, 30, 100, 1000 and 3000 ppm) of zinc, cadmium or zinc + cadmium. A very high 20a hydroxy steroid dehydrogenase enzyme activity was found in all sperm incubations of African catfish. This enzyme converts 17-hydroxy progesterone (17P) substrate to 17,20a-dihydroxy progesterone (1720aP) product and the rate of enzyme activity is related to substrate (17P) concentrations. Significant differences (P<0.05) in enzyme activity in converting 17P to 17,20aP were found between in vitro incubations of sperm with different concentrations of zinc, cadmium or zinc + cadmium and control group (0 ppm). Significant differences (P<0.05) in enzyme activity and 17,20aP production were found between fish fed with diet containing 1000 ppm zinc or cadmium and the group fed with diet containing 1000 ppm zinc + cadmium and control groups. The results showed that 20aHSD enzyme activities in fish sperm may be used as indicator of water contamination with heavy metals and their bioaccumulations in testis of aquatic animals.

Excretory-secretory (ES) and somatic antigens of Fasciola hepatica and Fasciola gigantica were prepared from freshly collected flukes. Laboratory bred rabbits were immunized with antigens for preparation of antisera. ES antigens of both species showed strong positive reaction with antisera raised against ES and somatic antigens of parasite. Somatic antigens of both species also showed strong positive reaction with antisera raised against somatic and ES antigens of parasite. In homologous combination of antigens and antisera higher enzyme linked immunosorbent assay (ELISA) values was observed in comparison with heterologous combination, so it was concluded that ES and somatic antigens of Fasciola spp have strong cross reaction with each other but the antigenic materials of ES and somatic products of parasite are not completely the same.

Opioids analgesics are used as premedication and in maintenance of anesthesia and in post-operative pain control. 20 female rabbits were assigned to experimental and control groups and followed for healing process for 20 days. Each rabbit was anesthetized, and a full-thickness skin incision, 3 cm long, was made on its back. The wounds were closed with non-absorbable suture. Morphine and saline were administered to experimental and control groups, respectively. The rate of wound healing was similar in both groups. While tensile strength of normal intact skin was significantly (P<0.05) higher than that of both groups, it was not different between the study and control groups. Collagen content and its maturity may be responsible for the this observation.

Monthly variation of magnesium (Mg) concentration in milk serum was investigated in industrial and semi-industrial dairy herds of Urmia, northeastern Iran, in 2002–3. Total number of 1, 112 milk samples from 96 herds including 615 samples from 53 industrial herds and 497 samples from 43 semi-industrial dairy herds were examined. 10-ml milk samples were collected monthly up to 12 months from each herd in the milk factory. Milk fat was separated by centrifugation. Milk serum was then separated after casein was precipitated by 0.1 N HCl. Spectrophotometery was used to measure the milk Mg concentration, using Mg kit (Ziest Chimi, Iran). The overall mean ± SD of Mg concentration in milk serum in industrial and semi-industrial herds was 5.47 ± 1.15 and 5.35 ± 1.21 mmol/l, respectively. The differences in Mg concentration between breeding systems were significant (P<0.05). The highest monthly mean Mg concentration in industrial and semi-industrial dairy herds was 6.39 and 6.05 and the lowest mean was 4.29 and 4.02 mmol/l, respectively. The lowest monthly mean Mg concentration in industrial and semi-industrial dairy milk herds was observed in August; the highest in November. The concentration decreased from March to August and then increased gradually up to November. The mean Mg concentration in milk serum within industrial, semi-industrial herds and between two breeds had a significant (P<0.001) monthly variation—mainly in August and November (P<0.05). The lowest and highest mean seasonal milk Mg concentration in industrial (4.61, 5.83 mmol/l) and semi-industrial herds (4.53, 5.72 mmol/l) were observed in summer and winter. The mean Mg concentration in milk serum had a significant (P<0.05) seasonal variation—between summer and other seasons. Thus, it could be concluded that milk Mg concentration in industrial herds was higher than semi-industrial dairy herds. The lowest milk Mg concentration was observed in August that could be important to supplement magnesium in food of dairy herds in Urmia.

A prospective study was conducted to investigate the difference in levels of some blood constituents between fertile and infertile cows. A total of 40 dairy cows were selected at random from a dairy farm. Serum samples were collected three times on 5 ± 3, 30 ± 3 and 58 ± 3 days postpartum. Serum glucose, urea nitrogen (UN), cholesterol, albumin, total protein, calcium, inorganic phosphorus and aspartate aminotransferase (AST) were measured for each sample. Cows were divided into two categories; those which conceived at either the first or second insemination (group 1) and those which conceived 3 inseminations (group 2). Seventy percent (28 of 40) of the cows conceived at first or second insemination and 30% (12 0f 40) needed 3 or more inseminations. Results showed that calcium (2.34 vs. 2.17 mmol/L) and inorganic phosphorus (1.84 vs. 1.42 mmol/L) were significantly (P<0.05) higher in the group 1 cows at second stage of sampling.

The effect of ascorbic acid (vitamin C) on the immune system is well-known. Ascorbic acid stimulates either humoral or cell-mediated immunity in many species. This experiment was conducted to evaluate the effect of oral administration of ascorbic acid on serum γ-globulin concentration of colostrum-fed newborn calves. During a cold winter season, 20 dairy Holstein calves from a group of 40 calves were supplemented with ascorbic acid from birth to 3 weeks of age (treatment). The other 20 calves did not receive any ascorbic acid supplementation (control). Ascorbic acid was administered per os and treatment was as follows: 3 g/day for the first week, 2 g/day for the second week, and 1 g/day for the third week. All calves were housed in elevated metal pens during the winter and at low temperature from birth to 60 days of age. Serum samples were collected immediately after birth, before taking colostrum and on the 2nd, 14th and 28th days of age via jugular vein. There was no significant difference in serum γ-globulin concentrations for the two groups before taking colostrum and at 2 and 14 days of age. The serum γ-globulin concentration of the supplemented group at 28 days of age was significantly higher than that of calves not receiving ascorbic acid. The results of the present study showed that oral administration of ascorbic acid increases γ-globulin concentration of neonatal calf serum.

In a 16-year-old mare of mixed breed, with gray coat, which was used for 2 years for production of polyvalent anti-snake antiserum, some nodules appeared on the underside of the tail and perineum. The animal gradually became weakened and showed weight loss and eventually, was euthanatized. Based on necropsy findings and histopathologic examination, affection to malignant melanoma was confirmed. By applying Congo red for detection of amyloidosis, deposition of amyloid within the wall of arterioles of spleen and a small amount  inside the hepatocytes were observed.  

 A 7-year-old stallion was bought for production of polyvalent snake antiserum. The animal died in less than two months from the beginning, of weakly injection with an increasing concentrations of polyvalent snake venom. In histopathological examination, severe necrosis of renal tubules (nephrosis) and portal sclerosis with necrosis of hepatocytes were observed. In the myocardium, thrombosis in small arteries, concurrent necrosis and fibrosis, as well as arteriosclerotic changes inside a coronary artery were observed. In the lung, there were severe congestion and hemorrhage. Moreover, destruction of alveolar walls was caused marked emphysema.