مجله تحقیقات دامپزشکی
سال شصت و هفتم شماره 2 (بهار 1391)

Postpartum anestrus is a major problem in primiparous dairy cows. The objective of this study was to investigate postpartum ovarian activity in primiparous Holstein dairy cows. Seven primiparous Holstein dairy cows were monitored for ovarian activity using a combination of ultrasound examination and alteration in progesterone concentrations. Daily blood sampling and ultrasound examination were conducted starting from day 6 until the third ovulation postpartum. First wave dominant follicles (>10 mm in diameter) were detected on day 11.5±1.48 postpartum. This follicle did not ovulate in any of the experimental cows. Moreover, none of the cows ovulated within 20 days postpartum. There was no difference in the follicular growth rate and the diameter of ovulatory follicles between the first, the second and the third ovulations postpartum (p>0.05). Interval from calving to the first postpartum ovulation was 48.1±6.89 days. Mean diameter of corpus luteum and progesterone concentrations of the first cycle (18.8±0.94 mm and 2.0±0.24 ng/mL) were significantly less than those of the second cycle (24.0±0.89 mm and 3.6±0.36 ng/mL; p<0.05). In conclusion, increased interval from parturition to the first ovulation is not due to the delayed or lack of the first wave dominant follicle formation after parturition; but is due to the regression of this follicle.

Estuarine euryhaline teleosts as reared spotted scat will be continnously encounterd with alterations to water salinities. The aim of the present study was to evaluate osmoregulatory capacity of the spotted scat in response to different salinities. 120 fish were categorized into 4 groups of 30 fish each. The fish were transferred from the freshwater to different salinities (5, 10, 20, and 30 g/L) and kept for one month. Tissue sections of the secondary lamella and gill branches were staind using hematoxyline eosin and studied by the light microscope. Transfer from freshwater to different salinities made significant increase (p<0.05) in total chloride cells of the secondary lamella. Furthermore, while chloride cells alterations have been accompanied with decrease in the chloride cell numbers of the lamella such changes made an increase in chloride cell numbers of the gill branches. It can be concluded that the mentioned species has limited osmoregulatory capacity when encountering abrupt salinity changes.

Increasing resistance against conventional anticoccidial drugs and the consequence of their residues has paid the attention toward more effective and safe compounds. Artemisia plant is a potential candidate that its anticoccidial effect has been previously discussed. This study aimed to produce a granule from the extract of Artemisia siberi and evaluate its anticcocidial effects compared to pure Atremisinin. Artemisinin was extracted from Artemisia by petroleum ether and then formulated into a wet granule. Experimental coccidiosis was induced in chicks (n=75) by oral administration of 250000 oocysts/chick. chicks were divided into 5 groups of three replicates each (n=15) and one uninfected group (n=15). The infected chicks were treated by oral administration (1mg/kg) of pure artemisinin and granule formulation with three different doses (1, 2.5 and 5mg/kg artemisinin) as feed additive. The treatment was conducted for 5 successive days towever. The fifth infected group and uninfected group did not receive any medication. At the end of treatment, fecal samples of each group were collected for 5 days and the OPG (oocyst per gram) was determined as anticoccidial index. The granule formulation of Artemisia and pure artemisinin significantly (p<0.001) decreased the OPG values in treated groups (30% in treated groups Vs 8% in control). However, there wasnt significant difference between granule formulation and pure artemisinin on OPG reduction (30.39% and 30.35%, respectively). This study showed that the Artemisia siberi granulated extract can be considered as a new effective and safe anticoccidial drug.

Cryptosporidium as an intracellular parasite causes severe diarrhea in calves. Several cases of cryptosporidiosis have been reported in different Iranian regions. The aim of this study was to follow cryptosporidiosis occurrence in cattle husbandries of Semnan city in Iran. Fecal samples were collected from 200 cows and calves, stained by modified Ziehl-Neelsen method and the cryptosporidium oocysts, size were determined. While the collected oocysts (n=40) showed a morphology similar to cryptosporidium parvum they were smaller than this parasite. In this respect, their mean length, width and length to width ratio were 3.44±0.06 µm, 3.55±0.06 µm and 1.03, respectively. By considering these characteristics and the small size of Cryptosporidium ryanae (as a key characteristic for this species) infection with this species has been suggested. However, further molecular studies would be necessary. The mean prevalence of cryptosporidiosis was 17.5%. However, in diarrheal calves, numbers of positive samples were significantly more than the other cattle. In non diarrheal cases, the infection rate was remarkably higher in cattle when compared with heifers and calves. There was not any relation between number of positive cases and type of husbandry, source of water, base of stable and sex of cattle. However, there was positive correlation between number of infected cattle and quality of basement sanitation, the way of using detergents and number of cattle in husbandry. It can be concluded that cryptosporidium ryanae may affect cattle of husbandries in some Iranian regions as Semnan. Hence, improvement of management and good sanitation of husbandry should be considered as control measures.

Enhancement of the immune system seems to be the most promising method of preventing fish diseases and increasing growth rate. Biodegradable and biocompatible immunostimulants obtained from natural sources (particularly herbal extracts) have received great attention for fish. In this study the immunostimulatory and growth stimulation effects of herbal extracts (Echinacea purpurea, Boswellia thurifera, Zataria multiflora), Ergosan and Levamisole were evaluated in common carp. 450 fish (11.12±1.22 g) were randomly divided into 6 groups in triplicate and fed with experimental diet for 6 weeks. Fish in groups 1 to 5 were fed by food supplemented with E. purpurea, B.thurifera, Z.multiflora, Ergosan and Levamisole, respectively. Group 6 was fed with basal food without supplementation. The Growth performance indices were evaluated at the end of study and blood samples were collected from 6 fish in each group. packed cell volume, haemoglobin concentration, red blood cell counts, white blood cell counts mean corpuscular hemoglobin, mean corpuscular volume and mean corpuscular hemoglobin concentration were compared among the groups. In each group, thirty fish were challenged with live Aeromonas hydrophila on day 42 and mortality rate was studied. Mortality rate showed no significant difference among groups (p>0.05). Specific growth rate (SGR) and food conversion rate (FCR) showed significant increase in all groups except (Zataria multiflora) compared to the control. Post challenge mortality rate decreased in all groups except (Zataria multiflora) compared to the control (p<0.05). WBC values in Ergosan, E. purpurea and levamisole groups were 7830±590, 7750±500 and 7380±810 per mL respectively which, showed significant (p<0.05) increased compared to the control group (6380±123mL), However no significant changes were seen in the other haematological parameters (p>0.05). It can be concluded that extract of E. purpurea and B.thurifera have immunostimulatory and growth stimulation effects in common carp which are comparable with the effects of two well documented fish immunostimulants, Ergosan and Levamisole.

BACGROUND: Traditional medicine can be considered as a method to reduce dietary obesity. OBJECTIVS: The aim of the present study was to assess the protective effect of Iranian green and black tea on diet induced obesity. Twenty four male Wistar rats (180±20 g) were divided into four groups. Control group was fed with rat regular diet (4% fat), and the three reminder groups were fed by high fat diet (25% fat). While control (C) and a high fat group (HF) had ad libitum access to water, the rest high fat groups had free access to drinking black tea (HF+BT) or green tea (HF+GT) instead of water. Eight week later rats were euthanized, weighed and their abdominal fat and organs separated and weighed. While Feed intake showed significant decrease in HF group compared with the control group (99.25±12.03 vs. 113.59±14.40 g/day; p<0.05), the levels of energy intake (454.54±55.09 vs. 405.52±51.43 kcal/day; p<0.05) and weight showed increase (283.33±13.84 vs. 223.33± 15.11g; p<0.05). Green and black tea made decrease in body weight gain compared to the HF group (71.67±1.61g and 57±12.95 vs. 104.33±21.75 g; p<0.05). However, the abdominal fat was just lower in HF+BT group than the HF group (2.90±0.56 vs. 4.19+.77g; p<0.05). Consumption of Iranian black and green tea may help to regulate body weight and reduce weight gain induced by high caloric food.

Determination of energy requirement and its effect on the immune system is one of the most important research topics in poultry and avian research area. To determine the effect of different levels of metabolizable energy (ME) on the production performance and immune responses of Iranian native hens. The experiment was conducted based on a completely randomized design with 6 treatments (2400, 2500, 2600, 2700, 2800 and 2900 kcal/kg ME) and 5 replicates of 10 samples each. Egg production and feed intake were measured both daily and weekly. Humoral immune function was measured by hemagglutination inhibition (HI) test on the 6th and 12th days after intramuscular injection of sheep red blood cells (SRBC). Cellular immunity was determined using responses of cutaneous basophil hyper-sensitivity (CBH) to phytohemagglutinin injection. Data were analyzed using GLM procedure. The results showed that dietary energy had a significant effect on the feed intake in such a way that increasing dietary energy linearly decreased the feed intake (p<0.05). There was no significant difference among the treatment groups in egg production, egg mass and egg weight (p>0.05). There were not significant difference among groups in terms of total antibodies against SRBC, IgG and IgM. However, IgM showed increase in response to different levels of energy on day 12 of injection (p<0.05) with the highest response for the diet contained 2800 kcal/kg ME. The CBH response showed a gradual increase based on increasing the dietary ME levels over 24 and 28 h after injection. Meanwhile diet contained 2900 kcal/kg ME showed the maximum CBH response at 24 and 28 h (0.28± 0.017 and 0.34±0.026mm, respectively). The results of this experiment showed that the dietary ME in the range of 2800 to 2900 kcal/kg made the highest effect on immune responses of Iranian native hens.

Newcastle disease (ND) is caused by serotype I of avian paramyxoviruses. The ND virus (NDV) strains are conveniently grouped as velogenic, mesogenic, lentogenic, and nonpathogenic-intestinal pathotypes. The purpose of this study was to determine the pathogenicity indices of the isolated NDVs from poultry flocks in Iran. Samples were provided from poultry flocks in different provinces of Iran and prepared for NDV isolation. From many isolated NDVs, 12 isolates belonged to 10 provinces with highly populated poultry farms which were selected for this study. A clone for each of these virus isolates was generated using limiting dilution procedure. Then, the mean death time (MDT), intracerebral pathogenicity index (ICPI), and intravenous pathogenicity index (IVPI) were determined for each virus clone and compared with those of standard virulent strains such as Hertz 33.56 and Texas GB. The results showed that the pathogenicity indices of the NDVs in the present study ranged from 41.6 - 60 hr for MDT, 1.76 - 1.91 for ICPI, and 2.68 - 2.88 for IVPI indicate which the velogenic type of our viruses. The findings of this study suggested that the very virulent NDVs currently circulating in Iranian poultry flocks are close to and even more virulent than standard virulent NDVs. Isolation, identification, pathotype determination, and molecular characteriz-ation of Iranian NDVs may help authorities to make right decisions to reduce the risks posing the Iranian poultry industry.

BACKGROUNGD: Alterations to mitochondria-rich cells (MRC) in the fish gill epithelium have been previously reported. To specify the variation pattern of apical openings in mitochondria- rich cells in short and long terms exposure to different salinities. Yellowfin seabream, (Acanthopagrus latus) was subjected to different salinities (freshwater, 5, 20 and 60ppt) besides the normal environmental salinity in the Musa creek (42ppt) over 21days, with three replicates for each condition. Samples were collected at the 1st, 7th and 21st days of experiment. Dissected gill arches were fixed in 2% glutaraldehyde+2% paraformaldehyde (pH=7.4) at 4°C and studied using scanning electron microscopy. Three subtypes of mitochondria-rich cells (shallow basin, deep hole and wavy convex) were detected in the gill epithelium based on different environmental salinities. While most of mitochondria-rich cells were present in seawater group, all of them were detected as the shallow basin subtype in 60 ppt group. Meanwhile, decrease in salinity to 20ppt, made morphological changes in the apical membrane of the mitochondria-rich cells on day 7, so that most of these cells have been detected as wavy convex or shallow basin subtypes. On the other hand, on day 21 they showed a pattern similar to the basal status. Furthermore,when they were transferred to hypoosmotic medium (5ppt and FW), rapid changes were exhibited in the apical membrane of mitochondria-rich cell which were stabilized after 21 days so that all subtypes of mitochondria-rich cells were observed in photomicrographs of gill filaments. Shallow basin mitochondria-rich cells as typical cells in seawater fish species, would be able to do osmoregulation in hyperosmotic environment in yellowfin seabream, yet in hypoosmotic conditions all sub- types of the mitochondria-rich cells would be required.

Unwanted pregnancy termination is a big issue for dog owners.

In this study we attempted to reduce the number of fetuses in pregnant bitches through ultrasound-guided induced fetal death.

The study was performed on 6 privately owned crossbred pregnant bitches, in the second and third trimester of pregnancy, with variable number of fetuses (n=2 to 8). Fetal death was induced by transabdominal injection of potassium chloride (KCl) into the fetal cardiac chamber under ultrasonographic guidance.

While selective fetal reduction was successfully achieved in 4 bitches (66.6%) 2 bitches showed complete pregnancy termination.

Data presented in this research provide evidence for possible use of this technique in order to selectively reduce the number of fetuses without whole pregnancy termination in the bitch. Ultrasound-guided induced fetal death seems to be a safe procedure and a viable method for reducing the number of fetuses with no side effect in the bitch.

Increasing developments in nanotechnology in recent years have raised the possible risk of release of nanoparticles into the aquatic environment, which could adversely affect organisms. Silver nanoparticles possess antibacterial activities and constitute almost 56% of total manufactured nanoparticles which are currently in use. The aim of this study was to evaluate the effects of colloidal silver nanoparticles on bacterial flora of rainbow trout gut. The Induced Coupled Plasma (ICP), Zetasizer and Transmission Electron Microscope (TEM) methods were used in order to ensure the quality of silver nanoparticles. 90 Fish (25±0.5 g) in Faculty of Marine Sciences were exposed to zero and 1 mg/L of silver nanoparticles over 14 days. Total viable bacterial counts and psycrotrophic bacteria, entrobacteriaceae and lactic acid bacteria counts of fish,s gut and total viable bacterial counts and psycrotrophic bacteria counts of water were determined. There was not any effect of nonoparticles on the bacterial counts (lactic acid bacteria, psycrotrophic and enterobacteriaceae) of the fish,s gut and bacterial counts (psycrotrophic and total viable of the water. However, there were significant differences between control and 1 ppm treatments based on the size and color of psycrotrophic colonies. Furthermore, the psycrotrophic bacterial counts of fish,s gut in the 1 ppm treatment showed significant increase (6.49±0.02 log cfu/g) compared to the control group (5.72 ± 0.17 log cfu/g) (p<0.05). The psycrotrophic bacteria represented the most sensitivity to nanoparticles among all studied bacterial groups (p<0.05); so, changes in the number of these bacteria may be considered as an indicator in monitoring the release and presence of silver nanoparticles in aquatic ecosystems.

Vibriosis has been recognized as a major bacterial disease in aquaculture industry. The development of effective vaccines has significantly reduced the impact of this disease. The aim of this study was to follow distribution of the antigenic Vibrio anguillarum cell wall lipopolysaccharide (LPS) in liver, spleen and anterior intestinal cells of rainbow trout (Oncorhynchus mykiss) using immunocytochemistry. Rainbow trout was intraperitoneally injected with V. anguillarum LPS. One hour later, liver, spleen and anterior intestine samples were collected to study the LPS distribution in the tissue sections using immunocytochemistry and Transmission Electron Microscope. Rabbit polyclonal antibody against the protein-A gold (pAg) labeled-LPS was applied to show electron density of the pAg using an indirect immunocytochemical method at the site of antigen- antibody interaction on the fish tissues. A pre-absorbed immune rabbit antibody and a pre-immune rabbit serum were considered as negative controls. Results showed that the labels were evenly distributed over cell cytoplasm, nucleus, intracellular spaces, basal membrane and connective tissue in the liver, spleen and anterior intestine. In most cases, more labels were detected in cytoplasm than nucleus while no label was observed in negative controls. Immunocytochemical study of tissues and cells in the immunized fish with V. anguillarum LPS showed extensive distribution of the antigen in hepatocytes, splenocytes and enterocytes.

On June 2010, inTehran province 7 out of 82 dogs in a kennel, showed clinical signs of enteritis which resulted in death (n=5). Clinical findings were diarrhea, dysentery, fever, depression, neural sings and sudden death. Necropsy findings revealed hemorrhagic enteritis, catarrhal gasteritis, multifocal necrosis up to 0.5cm in diameter in cerebral cortex with hyperemia and hemorrhage. Necropsy was done on 4 cases and intestinal contentes were cultured to characterize Clostridium perfringens type using PCR. Rapid test antibody for parvovirus and distemper virus showed that 2 out of 4 puppies were positive against distemper virus. According to nonsup- purative encephalitis, gliosis, intranuclear inclusion bodies in astrocytes, packed cell volume, interstitial pneumonia and positive reaction to distemper virus it can be concluded that primary distemper disease has been followed by, hemorrhagic enteritis and diarrhea as a secondary infection to Clostridium perfringens type A.