IRANIAN JOURNAL OF VETERINARY RESEARCH (IJVR)
Year:2007 | Volume:8 | Issue:1 (18)|Papers Count:15

The open pulled straw has been used effectively to vitrify preimplantation embryos because of geometric features that allow rapid rates of temperature exchange. One possible inexpensive alternative to the open pulled straw are commercially-available microcapillary pipette tips commonly used for electrophoresis. The main purpose of this study was to compare the survival rates of in vitro produced blastocysts following vitrification in microcapillary pipette tips and open pulled straws. Two experiments were conducted to investigate the effect of type of carrier, age of expanded blastocyst, and addition of β-mercaptoethanol to post-warming culture medium on survival of vitrified in-vitro derived blastocysts. Expanded blastocysts (Day 7, 0900H and 1900H after insemination; insemination = Day 0 at 0900H) were vitrified while loaded randomly in groups of 4-10 into open pulled straws or pipette tips. Following warming, embryos were cultured in groups of up to 20 in 20 µl microdrops of modified KSOM or modified KSOM containing 100 µM β-mercaptoethanol at 38.5°C in 5% CO2 in air. Survival after warming was assessed as the percentage of vitrified embryos that re-expanded and the percent that hatched after 48 hrs culture. Post-warming survival rates were not affected by type of carrier or age of the expanded blastocyst (P>0.05). The proportions of embryos that re-expanded (55.5%) and hatched (25.7%) were higher (P<0.01) for those cultured with β-mercaptoethanol than for those cultured without (re-expansion: 42.4%; hatching: 12.6%). In conclusion, the microcapillary pipette tip represents an inexpensive alternative to the open pulled straw for cryopreservation.

Although the promotional effects on bone healing of pulsed electromagnetic fields (PEMF) have been well demonstrated, the effects of static magnetic fields (SMF) remained unclear. In this study, effects of a custom-made magnetic wrap on radiographic and histopathological aspects of bone healing using a canine unstable osteotomy gap model were investigated. After an osteotomy of the midshaft radius, bone healing was evaluated over an 8-week-period in the control dogs (n = 5) and dogs exposed to SMF (1000 gauss) (n = 5). Bone healing was evaluated by qualitative and quantitative evaluation of serial radiographs every 2 weeks. Histopathological study was also performed on osteotomized radii upon completion of the experimental period. Dogs exposed to SMF had more advanced radiographic healing of osteotomy sites. Cellular morphology scores of the SMF group was significantly greater as compared with the control group (P<0.05). These results suggested that using the osteotomy gap model, SMF enhanced the radiographic and histopathological aspects of bone healing in dogs. Dogs at risk for delayed healing of fractures may benefit from treatment with SMF.

Hymenolepis nana is a common parasite of rodents as well as human intestine. This parasite has been reported from all over the world, including Iran. The infection rate has been reported up to 40% in some areas. The infection has various clinical manifestations. The parasite could establish severe hyperinfection in patients with immune deficiency. Regarding the rodents as hosts of the parasite, the infection may disseminate through these hosts to the nature. As H. nana is a zoonoses, phylogenic study of this parasite is of particular importance. Considering these criteria, the genomic diversity of 16 H. nana with the origin of Shiraz and Tehran were studied among the worms of mice and rats by RAPD-PCR. Genomic DNA extracted from individual worms by proteinase K method and three oligonucleotides primer (AB1-17, UBC-358, UBC-387) were used for RAPD-PCR. Similarity index were calculated by Nei and Li method. Data were analysed using UPGMA analysis and dendrograms were obtained by group average method with 100 bootstrapping analysis. The range of genomic similarity determined among specimens by AB1-17 primer was 48.3-90%, by UBC-358 primer 55-87% and by UBC-387 primer 53-97%. Regarding our data and genomic similarity indexes, various isolates were found in both specimens of rats and mice. However no differences were obtained between H. nana from rat or mouse isolates by these primers. The results showed that it is not possible to divide the isolates into two distinct groups based on their origin as Tehran and Shiraz.

Effect of propylthiouracil (PTU)-induced hypothyroidism during the prepubertal period, at a dose of one g per kg of the diet, on serum testosterone level and seminal characteristics of Fars indigenous chickens was studied. PTU was fed between 7th to 13th weeks of age and semen was collected at weekly intervals, starting at 21st week of age and continued for seven weeks. The effect of PTU treatment on serum testosterone level and body weight was significant (P<0.05). The effect of age on all parameters, including body weight, semen volume, sperm motility, percentage of live sperm, sperm concentration, total number of live sperm, and serum testosterone and thyroxine (T4) levels was also significant (P<0.01). The interaction effect of PTU treatment and age on semen volume, sperm motility, and percentage of live sperm was not significant (P>0.05); but it was significant for body weight, sperm concentration, total number of live sperm, and serum testosterone and T4 levels (P<0.01). At weeks 11 and 13 of age, serum T4 concentration in PTU birds was significantly lower but serum testosterone level was higher than in the control group. Sperm concentration in PTU birds was generally higher than in the control group, although the differences between the two groups were significant at weeks 20, 23 and 24. The total number of live sperm produced by PTU birds at week 21 of age was about 60% of the control group (P<0.01). A positive correlation (P<0.01) was found between testosterone level and body weight (r= 0.54 and 0.36 for the control and PTU groups, respectively). A small but significant positive correlation was found between T4 levels and body weight in the PTU group (r=0.23; P<0.01), but not in the control group (P>0.05). The correlation between testosterone and T4 levels was not significant. Transient prepubertal PTU-induced hypothyroidism resulted in an increase in sperm concentration and production at certain stages after treatment, but the effect did not seem to last for a long period. The potential for increased efficiency associated with raising smaller birds which pass a neonatal hypothyroidism and eat less feed and produce normal semen, may be economical.

The chemical composition, degradability coefficients (in situ) and ruminal-intestinal disappearance (mobile bag procedure) of dry matter (DM) and crude protein (CP) were evaluated for olive cake (OC) silages treated (DM basis) with additives as follows: (1) untreated OC, (2) OC + 0.5% urea, (3) OC + 0.4% formic acid, (4) OC + 8% molasses, (5) OC + 0.5% urea + 8% molasses, (6) OC + 0.5% urea + 0.4% formic acid, (7) OC + 8% molasses + 0.4% formic acid and (8) OC + 8% molasses + 0.4% formic acid + 0.5% urea.The highest reduction in cellulose and ADF content was found for treatment 8 (120 and 117 g kg-1 DM, respectively), as compared with the raw material (not ensiled). Taking into consideration the chemical composition, pH values, and the general appearance of silages, ensiling of OC with additives preserved well and enhanced the nutritive value of olive cake. Ruminal maximum potential degradability of DM (a+b), effective and rapid degradability and rate of degradation of treatment 8 were higher than others. The same trend was found for CP except fraction “a” which was highest for treatment 6. Mean ruminal DM (P<0.05) and CP disappearances in treatment 8 after 12 hrs incubation were higher than the other treatments. Intestinal digestibility of undegraded DM for treatment 5 was higher (P<0.05) than treatment 6 with no differences among other treatments. Intestinal digestibility of undegraded CP for treatments 3, 5, 6 and 7 was higher (P<0.05) than the other treatments. Total tract DM disappearance of treatments 4, 5 and 8 was higher (P<0.05) than others. Total tract CP disappearance of treatment 8 was higher (P<0.05) than treatment 4. Results indicated that treating OC before ensiling with 8% molasses, 0.4% formic acid and 0.5% urea (DM basis) could provide a good and economical source of a non-conventional feed in areas where OC is available; thus, it helps to improve the diet formulation for ruminants.

Haemorrhagic septicaemia (HS) is a fatal systemic disease of cattle and buffaloes. Some control is achieved with administration of alum-precipitated or oil-adjuvanted killed whole-cell vaccines injected subcutaneously. These vaccines, however, provide only short-term immunity and for effective use, they should be administered annually. We constructed an aroA attenuated derivative of a Pasteurella multocida serotype B:2 strain by allelic exchange of the native aroA sequence with aroA sequences disrupted with a kanamycin resistance cassette. This strain was confirmed to be aroA mutant by PCR. The aroA derivative was highly attenuated for virulence in a mouse model of HS and rabbits. Mouse and rabbit challenge experiments showed that i.p. or i.m. vaccination of an aroA strain completely protected mice or rabbits against challenge with a high dose (>1000 LD50) of the parent strain.

Attempts were made to present a practical key for identification of small strongyles, the identification of which seems to be a difficult task to do. 4000 nematodes collected from the large intestine of horses and donkeys were examined. 18 species of small strongyles of horse and 15 of donkey were found. From 6 species of large strongyles found in both animals, we only dealt with 3 of Triodontophorus sp. In horses, 3 species of Coronocyclus (C. coronatus, C. labiatus and C. labratus), 4 species of Cyathostomum (C. alveatum, C. catinatum, C. pateratum and C. tetracanthum), 5 species of Cylicocyclus (C. auriculatus, C. insigne, C. nassatus, C. radiatus and C. elongatus), 1 species of Cylicodontophorus (C. bicoronatus), 4 species of Cylicostephanus (C. calicatus, C. goldi, C. longibursatus and C. minutus), 1 species of Gyalocephalus (G. capitatus), and 3 species of Triodontophorus (T. brevicauda, T. serratus and T. tenuicollis) were found. From the above-mentioned species, C. minutus, C. calicatus and G. capitatus were absent in specimens examined from donkeys.

Dried oleander leaves at single lethal dose of 110 mg/kg body weight were administered orally to five native female goats. Clinical signs of toxicosis in goats began to appear about 1 hr after receiving the oleander and included abdominal pain, ruminal atony and tympany, frequent urination, bradycardia, tachycardia, tachyarrhythmia, depression, weakness and convulsive movement and death at the end stage. Electrocardiography revealed sinus bradycardia, sinus tachycardia, A-V dissociation, ventricular premature beats, depression of S-T segment, ventricular tachycardia and ventricular fibrillation. Four goats died within 4 to 84 hrs and one survived. Haemorrhages in varying degrees in internal organs were observed at necropsy. Histopathology revealed extensive tubular necrosis in kidneys with haemosiderin pigment in the cytoplasm of convoluted tubular cells, varying degrees of coagulative necrosis of cardiac muscle cells associated with haemorrhage and infiltration of mononuclear inflammatory cells, scattered necrosis of hepatocytes, perivascular and perineural oedema, haemorrhagic foci and ischemic cell changes in brain, congestion and oedema in lungs. Severe hyperaemia and infiltration of inflammatory cells were also observed in tissue sections of forestomachs, abomasum and different parts of the intestines.

This study was conducted on the atrioventricular node (AVN) and atrioventricular bundle (AVB) of five four-month-old ovine fetuses. The histological structure of these components was studied by routine histological techniques and use of specific staining methods. The AVN was caudally located adjacent to the root of the aorta. It was almost spherical in shape and consisted of twisty cells. The node was mainly composed of “P” cells. There were not seen internodal pathways in the heart of four-month ovine fetus. The AVB was a direct continuation of the AVN and it passed through the fibrous ring toward the apex of the interventricular septum. At this place the right bundle branch (RBB) was ramified. The cells of the AVB were wider, shorter and lighter than normal myocardial cells. Some of the bundle cells have been changed to purkinje cells, whereas some others still did not represent typical characteristics of purkinje cells.

In the present study, 360 male day-old broiler chicks were used to determine the effect of mixed live vaccines of Newcastle disease (ND) and infectious bronchitis (IB) on serum and local antibody responses to IB. Chicks were randomly divided into 12 treatment groups of 3 replicates and reared for 40 days on floor pens. Groups 1 to 5 received mixed ND and IB vaccine. Groups 7 to 11 received IB vaccine alone and regarded as positive controls. Group 6, that received ND vaccine only, and group 12, that received no vaccine, were considered as negative controls. Antibody titer against IB in the nasal washings and sera was measured using enzyme-linked immunosorbent assay (ELISA). The chickens were inoculated with IB live vaccine (strain H120) with or without ND live vaccine by means of an eye dropper. Serum samples obtained on the 19th and 29th day of age and serum samples, as well as nasal washings, collected on day 40, were used to determine systemic and local antibody responses to IB. On the 40th day of age, tracheal samples were also collected to study the probable pathologic lesions due to the effect of live vaccines used. There was no significant difference in systemic antibody response (SAR) among all groups measured on the 19th day. On the 29th and 40th day of age, SAR of the negative control groups was significantly (P<0.05) different from those received IB vaccine. On the 40th day, nasal washings showed higher antibody titer as compared to the systemic antibody titer (P<0.05). The pathologic lesions in groups received mixed vaccine were higher than groups received IB vaccine alone or the control groups. Mortality rate, weight gain and food conversion ratio were not significantly different among groups studied. Despite the observations that mixed live IB and ND vaccination resulted in a higher antibody response as compared to the single IB vaccination, yet this program could not be recommended to use in farm due to higher pathologic lesions in trachea.

Four-hundred milk samples from half udders of 20 flocks of native breed goats were aseptically collected. The samples were examined by California mastitis test (CMT). Twenty-one (5.25%) of 400 were CMT-positive. The CMT-positive samples were then cultured and the following bacteria were isolated: Staphylococcus aureus in 3 (14.28%), CNS (coagulase-negative staphylococci) in 14 (66.66%), streptococci in 4 (19.04%) and Mycoplasma spp. in 11 (52.38%) samples. The isolated staphylococci were examined to evaluate their resistance to different antibiotics by disc diffusion method. CNS resistance to amikacin was 78.5%, to penicillin was 50%, to tetracycline 50%, to ampicillin 42.8%, and to doxycycline was 28.5%. Four-hundred native breed sheep milk samples were taken from 19 flocks in the same conditions. The samples were examined by CMT test. 19 (4.75%) of 400 were CMT-positive. The CMT-positive samples were cultured and the following bacteria were isolated: S. aureus in 2 (10.5%), CNS in 7 (36.8%), streptococci in 2 (10.5%), Pasteurella in 1 (5.26%) and Mycoplasma in 9 (47.37%) samples. The isolated staphylococci were examined for antibiotic susceptibility. CNS resistance to amikacin was 42.8%, and to tetracycline, ampicillin, oxycycline and penicillin was 14.3%. Both isolates of S. aureus were resistance to penicillin.

Introduction of ostrich (Struthio camelus domesticus), a new exotic host species to a new ecosystem like Iran, necessitates the study of its infectious diseases including parasitic infestations. For a period of one year, from 2002–03, faecal samples of 254 ostriches on 5 farms located at different parts of Iran, including Garmsar, Semnan province (n = 85); Nashtaroud, Mazandaran province (n = 29); Saveh, Central province (n = 47); Eshtehard, Ghazvin province (n = 8) and around Tehran, Tehran province (n = 85) were examined for gastrointestinal parasites. Our findings revealed the presence of Libostrongylus douglasii in 55% of the examined birds in Nashtaroud and 25% of birds of Eshtehard farms. In the latter farm, 12.5% in the ostriches harboured Heterakis dispar in their alimentary canals. Oocyst of Eimeria sp. was found in ostrich on farm of Garmsar. All these parasites are reported for the first time from ostriches in Iran.

Haemorrhagic septicaemia (HS) vaccine which is prepared in Razi Institute is used in endemic areas of Iran. Aluminum-hydroxide gel was used as adjuvant for preparing this vaccine. Post-vaccinal shock reactions were the main complaint after use of this vaccine. In a previous study, we could improve the vaccine by alum-precipitation Pasteurella multocida cells and removing the liquid phase. In this study, the amount of free endotoxin in aluminum-hydroxide and alum-HS vaccines was determined. It was found that endotoxin level was considerably decreased from 0.22 EU/ml to 0.03 EU/ml after alum-precipitation.

To investigate the prevalence of Cryptosporidium infection in horses, a total of 221 faecal specimens were collected from 18 villages of Urmia, northwestern Iran. The samples were studied microscopically by modified Ziehl-Neelsen staining. The cryptosporidial infection was found in the collected samples from 11 of 18 villages. Although the prevalence of the infection was 15.8%, none of the infected horses appeared clinically ill.

Ocular lesions are a common manifestation of toxoplasmosis in cats. In this survey, 10 healthy Syrian mice were infected through intraperitoneal inoculation of bradyzoites of Toxoplasma gondii (Tehran strain). Mice were killed 30 days after inoculation and the suspension of their brains was prepared, after confirmation of the infection. Seven kittens were fed with the infected mice brain suspension. The kittens were 2.5–3 months old and had body weights of 650–900 g. All kittens shed oocyst 7–8 days after infection, and had antibody titers as high as 1/320–1/1280 30 days after the challenge. Serum chemistry and complete blood count were determined in all of the kittens. Examination of eyes was done with ophthalmoscope twice during one week. Only one kitten showed unilateral anterior uveitis on day 16 after the infection was diagnosed based on serology, oocyst shedding and other clinical signs.