Background: The complex process of spermatogenesis is regulated by various factors. Studies on spermatogonial stem cells have provided a very important tool to improve herd genetic and different field. 0.2 to 0.3 percent of total cells of seminiferous tubules consist of spermatogonial stem cells. To investigate and biomanipulate these cells, first the proliferation and viability rate of cells should be increased in vitro. Objectives: In the present study, the in vitro effects of testosterone on spermatogonial cell colony formation were investigated. Methods: Sertoli and spermatogonial cells were isolated from 3-5-month-old calves. The identity of the cells was confirmed through analysis of immuno-cytochemistry. Co-cultured Sertoli and spermatogonial cells were treated with testosterone in different doses of 0.2 µmol L-1, 0.4 µmol L-1 and 0.8 µmol L-1, before colony assay. Results: testosterone did not decrease the proliferation of spermatogonial stem cells. Conclusions: testosterone can be chosen for in vitro colonization of spermatogonial cells with other factors.

BACKGROUND: Caprine pox virus disease play an important role in major constraints to small ruminants production in Iran. OBJECTIVES: This study was conducted in different districts of Iran to determine the prevalence of goats pox virus disease in different age groups, sex and seasons in Black goats of Iran. METHODS: In this study skin lesions of male and female goats were collected randomly from different provinces during (January, 2007 to November, 2010). A total of 318 samples were examined, of which 66 were found positive. RESULTS: The overall prevalence rate was 20.75%. Pox virus disease was observed significantly higher in older (58.33%) female goats (36.79%) and in rainy seasons (26.16%). The estimated economic losses due to condem-nation of skin deficiency were 5.59% which cost US$115.44 per thousand skin of slaughtered goats. The prevalence was significantly different (p|£|0.05) in different age groups and sex of the animals. CONCLUSIONS: The present study indicates that pox virus disease infection in goats is associated with age, sex of animal and seasons of the year. To control the disease in infected provinces, appropriate preventive control strategies have to be designed to reduce the impact of the disease on goat production in Iran.

Background: Poultry products have been recognized as major sources of human gastrointestinal disease caused by Salmonella spp. and several outbreaks have been reported where eggs were the source of human infection. OBJECTIVES: This study was carried out to determine the prevalence of Salmonella spp. in the quail egg interior contents from retail stores of Semnan, Iran and to characterize the isolated Salmonella serovars via serotyping and Multiplex PCR techniques. METHODS: 140 packages of quail eggs (each package containing 12 eggs) were collected from different batches during summer 2010 and tested for the presence of Salmonella through conventional culture and serotyping methods. RESULTS: From these samples, S. enteritidis was detected in the egg contents of one package (0.71 %) out of 140 packages. This isolate was confirmed by Multiplex PCR generated amplification products for a random sequence that is specific for the genus salmonella and spv and sefA genes. CONCLUSIONS: According to our results, S. enteritidis is the most prevalent serotype of quail egg content contaminant in the Semnan area of Iran and the multiplex PCR method could be used as a reliable method of identifying Salmonella serovars.

BACKGROUND: Several regulatory proteins are involved in Salmonella invasion. The key regulator of SPI-1 (Salmonella pathogenicity island 1 ) is hilA, a transcriptional activator encoded on SPI-1 that regulates the expression of the SPI-1 secretion system. OBJECTIVES: Importance of hilA mutation on S. enteritidis colonization and shedding in layer hens was evaluated in a long-term experiment. METHODS: Two groups of layer hens were orally inoculated with 1010 CFU of hilA and parent strains of S. enteritidis, consequently. At days 2, 7, 14, 21 and 35 post-inoculation samples were taken from cloaca and different parts of digestive and reproduction systems of euthanized birds. RESULTS: In the birds infected with parent strain, the higher numbers of colonizing bacteria in the liver, spleen, caecum, small intestine and cloaca-vagina were observed. Fecal shedding in this group was also higher than the hilA group. However, no significant differences were observed for the colonization of bacteria in magnum, isthmus and infundibulum of both groups. Using PCR method, hilA gene was only detected in tissues of parent group hens. CONCLUSIONS: This study has shown that the hilA mutant is able to colonize in internal organs; an implication of this is the possibility that genes other than hilA, or at least other mechanisms, might be involved in the invasion of S. enteritidis to the internal organs of birds.

Background: Broilers lung mechanisms that regulate endothelin (ET) in the lung are complex and poorly understood. Objectives: Methods: In this experiment lung ET-1 mRNA levels and lung mRNA expression for the ET(A) receptors were determined in lung tissue weekly (term = 42 days, intervals = 7 days). Serum endothelin concentration was also measured at these ages. Results: The study showed that expression of endothelin in lungs of layers and broilers was similar during the first three weeks and the overall trend of ET-1 expression was increasing. However, there was a significant increase of ET-1 expression which started from the fourth week and gradually increased until the end of the commercial life of the chicken (day 42). ET-A expression in the lungs of broilers was significantly higher than layers during the last three weeks of life. Overall, trends of serum ET-1 concentration increased in both layers and broilers, but serum ET-1 concentration in broilers was significantly higher than layers. Conclusions: The higher level of serum Endothelin and expression of ET-1 and ETA in broiler lungs may explain the higher sensitivity of broilers to the vasoconstrictions activity of endothelin and the higher sensitivity of these animals to pulmonary hypertension (PH).

Leptospirosis is a zoonosis with numerous reservoir hosts. The disease is caused by infection with various serovars of Leptospira interrogans sensu lato. This study was conducted to evaluate the seroprevalence of leptospiral infection in stray cats in Ahvaz (south-western Iran) from April 2007 to June 2008. Blood samples were collected from 102 stray cats and screened for leptospiral infection using the microscopic agglutination test (MAT). Five of the 102 cats (4.9%) were serologically positive for at least one serovar of L. interrogans. The greatest number of reactors was for L. interrogans serovar balum (five serum samples). Antibodies against more than one serovar (namely, serovars balum and australis) were detected in one sample. All positive titers were detected at 1:100 dilution. The prevalence of leptospiral infection was 5.3% and 4.4% in male and female cats, respectively. There was no significant difference in positive titer prevalence between different sexes but prevalence was significantly different between age groups (P = 0.021), as all cats with positive titers were three years of age or more. This is also the first report of infection with L. interrogans serovars balum and australis from cats in Iran.

Avian chlamydiosis is one of the most important infectious diseases of birds. Despite the rapid growth of exotic bird populations in Iran, there is little or no information on the specific infections that these types of birds carry. In this study, conventional isolation methods were used in cell culture to study occurrence of infection in pet birds. Samples from the conjunctiva, choana, and cloaca and/or droppings were provided from 17 birds of different species. The samples were used to infect McCoy cell culture to isolate Chlamydophila psittaci. The inoculated cells were fixed, stained by Giemsa, mounted on slides using Entellan® and observed by light microscope for the presence of typical chlamydial inclusion bodies. Chlamydophila psittaci was isolated from four birds including a ring-necked parakeet (Psittacula krameri), an Alexandrine parakeet (Psittacula eupatria), an African grey parrot (Psittacus erithacus), and a Timneh grey parrot (Psittacus erithacus timneh). All negative cultures were passaged a further two times. To the best of our knowledge; the report represents the first isolation of chlamydia from birds in Iran.

Hair samples from 58 healthy camels were examined for the presence of saprophytic fungi. One -hundred and seventy-four samples were obtained from three different locations of dromedary camel's body. Several fungal specific media were used for isolating and identifying the saprophytes. Fungal isolates belonged to 15 genera. The most common in order of frequency were members of the genera Aspergillus (48% of the total examined camels), Penicillium (16.1%), Mucor (14.2%), Alternaria alternata (5.6%), Rhizopus (3.1%), Chrysosporium (2.7%), Acremonium (1.1%), Scoupolariopsis (1%), Cladosporium (0.8%), Fusarium, Psuedallescheria boydii and Stachybotrys atra (0.2%). The highest frequently yeasts isolated were related to Candida species (6%), followed by Geotrichum candidum (0.6%) and Malassezia species (0.2%). Skin infections caused by any of the contaminants were not encountered. The study demonstrates that Aspergillus, Penicillium and Mucor species were the common components of healthy camel skin mycoflora, and that camel hair analyzed in this study was free from true dermatophyte.

Avian intestinal spirochetosis (AIS) is a disease of birdscharacterized by a marked colonization of the cecum and/or rectumwith anaerobic intestinal bacteria of the genus Brachyspira. Thepurpose of the study was to determine the occurrence of Brachyspiraspp from avian sources in Iran and to characterize selected isolates bybiochemical and molecular methods. Out of 165 fecal samples obtained from commercial layer, broiler and broiler breeder chickens, turkeys and ostriches, 16 samples were positive in phase contrast microscopy examination and selective culture media. Biochemical scheme, polymerase chain reaction (PCR), and sequencing of partial sequence of 16S rDNA, revealed that all of isolates were Brachyspira pilosicoli, a broad spectrum host member of this genus that infects both humans and animals. This is the first report on isolation andidentification of Brachyspira pilosicoli from birds in Iran.

In this study, immune responses against Streptococcus iniae infections in rainbow trout (Oncorhynchus mykiss) were analyzed. Anti-streptococcal antibody (ASA) levels, respiratory burst activity (RBA), phagocytic activity (PA) and phagocytic index (P index) were measured in kidney macrophages. Fish were allocated to three experimental groups (n = 50 per group): survivors of natural S. iniae infections, non-exposed healthy fish immunized by immersion with formalin-killed S. iniae bacterin and a control group of non-exposed healthy fish. Blood sera and kidney samples were collected from each group (n = 10 fish) at days 0, 15, 30, 45 and 65 post-immunization (p.i.). Analysis of ASA levels, RBA, PA and P index in survivors of Streptococcus infections revealed optical density (OD) values of 0.082-0.091, 0.089-0.091, 53-55 and 1.8-1.9 respectively. In the immunized non-exposed group, the ASApeak antibody level occurred at day 15 (mean OD=0.122) and declined significantly by day 65 (p