مجله تحقیقات دامپزشکی
سال شصت و نهم شماره 1 (زمستان 1392)

Digital dermatitis is an inflammation of the skin on the bulbs of the heel which cause lameness and economic losses. Atypical digital dermatitis is a new form of an old disease which has been reported recently in the USA, UK and Netherlands.

The purpose of this study is the clinical and histopathological evaluation of claw lesions with exposed corium in cases of concurrent digital dermatitis in two endemically infected herds without preventative herd strategies for BDD.

The majority of non-healing claw lesion samples included in this study were taken from 'typical' clinical cases, namely, from lame cows examined in the course of veterinary practice by one author over a period of months in two commercial dairy farms in Iran. Fourty five lame cows with claw lesions were selected for clinical and histopathological purposes.

Examination of the affected claws revealed a topical granular appearance, painful to touch, prone to bleed with distinctive odour and extensive regional loss of the claw horn. Histologically, the epidermis was lost completely over the extension of sole ulcer lesion. The underlying dermis was intensely infiltrated by inflammatory cells, mainly polymorphic leukocytes, and in deep, newly formed capillaries were embedded in the stroma. Hyalinized thrombi were also significant in small blood vessels. In wall ulcer, there was extremely proliferative epidermis, 2-3 times with severe acanthosis and rete ridge formation. Stratum corneum was hyperplastic. The stratumcorneum were filled with neutrophils, cellular debris and erythrocytes lodged in theorthokeratotic stratum corneum.

In all the observed cases, the disorder included penetration through the horn capsule lesions to involve the corium, resulting in damage of the horn-forming cells. This new manifestation seems to be a combination of metabolic and infectious diseases.

Colibacillosis is an infectious disease caused by E. coli. This infection is spread by the feces and other secretions of infected animals and humans. Non-biting Muscid flies characteristically visit manure and decaying organic materials to feed and oviposit and may contribute to disease transmission.

This paper reviews the role of house flies (Musca domestica) in E.coli transmission at poultry farms.

In this study, 2000 house flies (Musca domestica) were collected from 2 commercial laying hen farms around Karaj. They were examined for the presence of the bacteria. In an adjacent study, laboratory-reared flies were experimentally exposed to E. coli (ATCC10536) strain and the infected samples were examined at regular intervals.

The E. coli was detected in the dissected gasterointestinal tract of laboratory-exposed flies for up to 72 h. post exposure, whereas after that time the infected flies and the untreated control flies were negative.

The results showed that considering the ability of mechanical vector during 72 hours, the E. coli transmission is possible in short time.

Dendritic cells are the most potent antigen presenting cells. They capture, process and present antigens to T cells and secrete various cytokines and soluble factors to initiate adaptive immune responses. Dendritic cells are also important in induction of immunological tolerance to self- antigens. Due to their crucial role in immune responses during infections, cancers, transplantations, allergies, and autoimmune diseases, they have become important targets for many biological and clinical studies. Usually large numbers of dendritic cells is essential for these studies; however, small numbers of these cells in blood and tissues makes the isolation very difficult. Therefore, In vitro generation of these cells is useful for research and clinical applications.

The aim of this study was in vitro generation of dendritic cells from bone marrow-hematopoietic progenitor cells using a simple and efficient method.

Murine bone marrow cells were cultured in medium supplemented with Granulocyte macrophage colony-stimulating factor and Interleukin 4 without depletion of any cell population for 9 days. Fresh medium containing cytokines was added every 3 days.

Analysis of the morphology and immunophenotype of cultured cells showed the generation of dendritic cells from day 2 of the culture period. But, the number of cells that possess morphological characteristics and typical cell surface markers (CD11c, MHC-II and CD86) of dendritic cells was elevated by increasing the culture period. The purity of dendritic cells was 86% by the end of 9 days culture.

This method can be used as an efficient method for ex vivo generation of dendritic cells.

Enzymatic digestion of proteins in ticks is a complex process and the study of functional proteomics of these enzymes can help to select them as possible vaccine candidates. Blood protein changes (e.g. haemoglobin to vitellin) occur in female mature ticks. Vitellin digestion, as an amino acid and energy source, is one of the vital and important processes in development and evolution of tick eggs and larval stage of unengorged ticks. Several studies reveal a network of proteolytic enzymes involved in haemoglobin and vitellin digestion. These enzymes are mostly cysteine and aspartic peptidases.

The aim of this study was the detection of the cathepsins in Rhipicephalus (Boophilus) annulatus larvae extract.

In the current research, cysteine proteases extracted from Rhipicephalus (Boophilus) annulatus larvae were studied by one- and two-dimensional zymography.

Findings from one dimensional zymography showed a transparent band with 28 KDa. In two-dimensional zymography transparent area are seen in the dark gel background distributed in 21 to 65 KDa zones related to cathepsins. When DTT was added to incubation buffer (10 mM acetate buffer, pH= 4), the proteolytic activity of some enzymes was increased and appeared as more clear transparent bands in one-dimentional zymography compared with samples incubated in buffer without DTT.

As the pH of incubation buffer was acidic and adding DTT resulted in increased activity of the enzymes, therefore, some of these proteolytic enzymes are assumed to be cysteine proteases.

Cytological examination of bone marrow in cats, due to the large number of cells and various growth phases is somewhat complicated. The use of flow cytometric techniques and monoclonal antibodies are appropriate methods in the diagnosis of hematopoietic malignancies.

The purpose of the present study is to determine cell-surface antigens for various developmental stages of feline bone marrow cells in hematopoietic disorders using flow cytometric.

In this study, bone marrow cells from 4 cats with hematopoietic disorders and 2 clinically healthy cats, were labeled with 5 types of anti-feline MAbs included: CD21-like (Cr-Br), T lymphocyte subpopulation, CD- 172a, Granulocyte, Pan-Leukocyte (CD45-like) and then analyzed using flow cytometric.

The results revealed changes in immunophenotyping and light scatter properties compared with normal cases. The percentage of CD45, Granulocyte and CD172a markers in the bone marrow of a cat with erythroleukemia were lower compared with normal bone marrow. In a cat with myelodysplastic syndrome, scatter plot indicated an increase in the immature myeloid cells and a decrease in mature myeloid cells.

It was concluded that cytological examination of bone marrow with studying dispersion studies on cells using flow cytometric and usage of a panel of antibodies such as CD21-like(Cr-Br), T lymphocyte subpopulation, CD-172a, Granulocyte, Pan-Leukocyte (CD45-like) could support the diagnosis of feline hematopoietic abnormalities.

Antibacterial drug use in food-producing animals may be associated with risks to public health. The present survey was carried out due to lack of data on the status of antibacterial drug usage in Tehran Province dairy farms.

The purpose of the present study was to investigate the status of antibacterial drug usage in these farms and implementation of the points from public health view.

A total of 120 dairy farms in four regions of Tehran province including East (Damavand), South East (Varamin and Shar-e-Rey), South-West (Shariar and Islamshar) and West (Karaj and Savojbolagh), were surveyed by direct interview using a questionnaire.

The mean consumption rate of oxytetracycline and penicillin + streptomycin, 100% and 93.25%, respectively, were the most frequently used antibacterial products in these dairy farms in terms of variety, and a wide range of other antibacterials also showed high percentages of usage. Regarding intramammary formulations, cloxacillin, Dry Cow (DC), with a mean of 82.5%, was shown to be the most frequently used intramammary products in terms of variety. In 47.4% of farms, the orders for antibacterial drugs were issued by non-veterinarians. Also, in a considerable percentage of dairy farms the milk collected from animals receiving antibacterial drugs for mastitis (27.5%) or other infectious diseases (24.2%) were being entered into the milk reservoirs to be used for humans.

The principles of rational antimicrobial therapy as well as withdrawal/ milk discard times are not implemented in a great percentage of these dairy farms. This situation may be due to lack of knowledge among dairymen regarding drug use and public health, and inadequate supervision of the veterinary offices of Tehran province.

Lactoferrin (Lf), an iron binding glycoprotein, has a variety of physiological roles and its foremost is antimicrobial properties. Therefore, the lactoferrin gene can be considered as a potential candidate gene for resistance to mastitis.

This study was carried out to determine the haplotype frequency of the 5'-flanking region of bovine lactoferrin gene in local and Holstein cattle breeds of Iran using PCR-SSCPand DNA sequencing.

Genomic DNA was isolated from 100 blood samples of two cattle breeds (50 Local, 50 Holstein). Two new primer pairs were designed from Lf sequence to amplify a part of 5'-flanking region of the gene. The amplified fragment was screened by single strand conformation polymorphism (SSCP) and DNA sequencing. The multiple alignments were carried out for the nucleotide sequences of different SSCPpatterns. In silico analysis of identified single nucleotide polymorphisms (SNPs) within the 5'-flanking region of bovine Lf gene was screened, to identify any association on transcription factor binding affinity. REULTS: Analysis of the whole samples revealed three SSCP patterns (A, B and C) for amplified fragment that C haplotype was the only variant identified in local breed samples. The bioinformatics analysis revealed that the Tto G trans version at position -602 created an AML-1 transcription binding site in combined genotype A. In -586 position, Tto C transition abolished binding site of AML-1 transcription factor.

Therefore, to apply Lf gene for marker-assisted selection, additional studies are required to evaluate the functional role of these identified polymorphic sites on gene expression and somatic cell counts in cattle.

Outbreak and development of yersiniosis in rainbow trout farms in Iran has caused a serious problem over the last years.

The purpose of this study was to evaluate the efficacy of immersion vaccination with Yersinia ruckeri in rainbow trout.

Prior to antigen preparation, the phenotypic, molecular and serological features of a number of Yersinia ruckeri isolates obtained from affected trout farms were studied. The virulent of these isolates were then evaluated using intra peritoneal injection route. Trout were vaccinated by immersion route (3 min at 12 °C) using Yersinia ruckeri bacterin of the virulent strains. The efficacy of vaccine antibody titer within 2, 4, 6, 8 and 10 weeks post vaccination were evaluated using relative percent survival.

The phenotyping, serological and molecular studies have led to identification of 8 isolates of Yersinia ruckeri and all the isolates produced bands 409 bp, which is indicative of Yersinia ruckeri. In pathogenicity test 3 isolates caused above 50% mortality, while 5 isolates reached 16%. The RPS of vaccinated fish reached 72.7, 80, 80, 82.2 and 83.3 within 2, 4, 6, 8 and 10 weeks post vaccination, respectively. In the other words, the mortality level in vaccinated groups was in range of 10-20% within 10 weeks post vaccination, while those of control group was in range 56.7 - 73.3% (p<0.05). The lowest and the highest antibody titers in immunized groups were 32±4.50 and 164.57±9.37 respectively, obtained after 4 and 10 weeks of immunization, whereas the control group had no measurable titer of antibody.

The results of this study clearly show that this vaccine can remarkably protect the trout from yersiniosis outbreaks inside Iran.

The present study deals with the effect of different levels of synbiotic on egg production and quality, blood parameters, hatchability and yolk cholesterol in broiler breeder hens.

The aim of this study was to determine the best level of synbiotic in the diet of broiler breeder hens.

The study was conducted based on a completely randomized design with 4 treatment groups, 2 replicates and 10 controls in each experimental unit. The experimental rations were containing 0 (control S0), 0.05 (S0.05), 0.1 (S0.1) and 0.2% (S0.2) synbiotic. Egg quality and weight were measured daily. Blood parameters, laying rate and hatchability were measured weekly. Yolk cholesterol, ovarian weight and number of ovarian large follicles were evaluated at the end of the experiment. The data were analyzed using GLM procedure.

The results showed that yolk index in group S0.1 was significantly lower (p<0.05) than groups S0.05 and S0.2, but was not statistically different from the control (p>0.05). Also, synbiotic had no significant effect on other egg quality traits, egg weight and hatchability (p>0.05). Addingy synbiotic supplement to diet reduced significantly the laying rate, ovarian weight and number of ovarian large follicles in the group S0.2 compared with the other groups (p<0.05). Synbiotic significantly increased plasma glucose concentration (p<0.05), but plasma triglyceride, HDL and yolk cholesterol concentrations were not influenced by dietary symbiotic (p>0.05). Furthermore, plasma cholestrol concentration (last week) in groups S0.1 and S0.2 were significantly lower than control group (p<0.05).

The results showed that it would be proper to use 0.1% synbiotic in the diet of broiler breeder hens.

Heat stress can affect the health and performance of sheep. Researchers have investigated various methods to prevent the harmful effects of heat stress.

In this study, injection of vitamin C on some biochemical parameters, red blood cells (RBC), hemoglobin (Hb), hematocrit (HCT) and white blood cells (WBC) in sheep under hyper acute heat stress were studied.

Eight healthy male sheep in similar range of age 5±1 months) and weight (28.75±3.17 kg) were enrolled in this study. The sheep were divided into two groups. Both groups were placed in an environment with hyper-acute heat stress based on temperature-humidity index (THI).Vitamin C was injected intramuscularly on days 0, 1, 3 and 5.Blood samples were collected from the jugular vein on days 0. 1, 3, 5, and 7. Glucose, cortisol, cholesterol, triglycerides and blood components were measured and evaluated. Results were analyzed using statistical software SPSS (version 16).

The results showed that vitamin C injection has a significant effect on serum cortisol, glucose, hematocrit and white blood cells (p<0.05). Vitamin C injection has lowering effects on serum cortisol and glucose during heat stress. Mechanism for attenuating the levels of cortisol and glucose by vitamin C is not well known. However, it may be done by decrease in cortisol synthesis or degradation. Increased hematocrit provided sufficient water to cool the body through perspiration.

The present study probably shows a beneficial effect of injection of vitamin C on adaptation mechanisms against of heat-stressed sheep.

Effects of different sources of prebiotic on performance and immune response in laying hens were evaluated in this study.

The aim of this experiment was to compare the effects of commercial prebiotics on performance, egg quality and antibody titer against Newcastle disease (ND) and Avian Influenza (AI) in laying hens.

The experiment was performed for 11 weeks (from 33 to 44 weeks of age) on 240 laying hens (the LSL strain), in a completely randomized design with 4 treatments, and 5 replicate for each treatment and 12 birds for each replicate. Treatments were: 1) control; 2) control +Safmannan®; 3) control +Bio-Mos® and 4) control +Fermacto®.

The results showed that feed intake, feed conversion ratio and egg production percentage were not affected by different sources of prebiotic. However, egg weight and egg mass were significantly increased (p<0.05) by adding prebiotic, in comparison with control diet. Egg specific gravity and shell thickness were increased (p<0.05) by prebiotic addition. The results of experiment showed that antibody titers against AI and ND were significantly increased (p<0.05) by prebiotics compared with control group.

The results showed that the effects of different sources of prebiotic on performance and immune response of laying hen are similar. However, inclusion of prebiotic in the diet results in improvement of the performance and antibody titer against Influenza and Newcastle.

Molecular investigation of important commercial shrimp species is one of the main goals to find out the pure populations and brood stocking of marine resources.

The purpose of the present study was to study the population of P. merguiensis and determining the extent of genetic diversity of this species.

Samples were collected from three major distribution areas in the Persian Gulf and Oman Sea. Molecular investigation was carried out using microsatellite markers.

Only five out of the eight primers of P. merguiensis produced good amplified PCR products with fixed annealing temperature. The rest of the primers were either not easily amplified or produced nonspecific bands. Seven alleles were found to be unique to each of the three populations of P.merguiensis. Occurrences of heterozygosity deficiency were found at most loci. These heterozygosity deficiencies in observed heterozygosity in comparison to expected heterozygosity may be due to inbreeding, genetic drift and consequences of illegal overharvesting of P. merguiensis in the studied areas as well. Deviation from Hardy-Weinberg Equilibrium in both studied species was significant in most microsatellite loci (p<0.001). We observed deviation from HWE in most loci with hetrozygosity deficits. The genetic variation results showed that the pairwise Fst values were significant between studied populations. The assignment test revealed high gene flow between Hormoz and Jask and restricted genetic flow between Guatr and Hormoz populations.

It seems that the changes in immigration patterns of populations between Hormoz, Jask and Guatr areas depend on the influence of Persian Gulf currents or the life cycle of P. merguiensis in studied areas. Alternatively, the presence of ecological barriers such as mangrove forests may result in restricted genetic flow between Guatr and both Hormoz and Jask populations.

Microalgae Dunaliella salina is a national source of carotenoids which can be used in aquaculture, meanwhile synthetic Astaxanthin is very expensive for use in aquaculture and several attempts have been made to find alternatives for Astaxanthin.

The purpose of this study is to investigate the effect of oral administration of Astaxanthin and D.salina on skin carotenoid level, skin and fins coloration as well as lipid peroxidation of muscles in H.severus.

One hundred and thirty five H.severus weighing 27±0.5g were randomly divided to three groups in triplicate: Groups 1 (G1) was fed with basal diet, group 2 (G2) and group 3 (G3) were fed with basal diet supplemented with 200 mg kg-1 D.salina or Astaxanthin respectively. After 6 weeks, digital photo were taken from 15 fishes of each group and skin and muscles samples were taken after euthanasia. Skin beta carotene rate, lipid peroxidation of muscle (based on Malondialdehyde activity) as well as skin and fins coloration pattern (a*, b*, Hue, L* and Chroma) were compared among groups.

Skin beta-carotene rate significantly increased in G2 and G3 compare to G1 but, Lipid peroxidation rate were decreased in G2 and G3 compare to control (p 0.05). Although some improvement in color quality were observed in trunk area, there was no significant difference in color indicators among the groups (p>0.05). In the fin areas a* value significantly increased in G2 and G3 compare to control also Hue and b* value significantly decreased in G2 and G3 compare to control (p<0.05). Chroma significantly increased in G compared with other (p<0.05). No significant difference were observed in L* between the groups (p>0.05).

Although the effect of Astaxanthin on skin carotenoid level and skin and fins coloration was better compared with D. salina. However, because of reasonable price, wide availability and the production of Dunaliella salina, it can be used as an alternative for Astaxanthin.