Iranian Journal of Veterinary Medicine
Volume:6 Issue: 4, Autumn 2012

Garlic (Allium sativum) is known for its anti-bacterial properties, but information on its effects against bacteria species that are important in fish diseases is scarce. The aim of this research was to use garlic as a natural product to improve the aquatic animal health status so as to compensate the demand for environment-friendly products for sustainable aquaculture. For this purpose thee methods of extraction including: row garlic extract, water, ethanol and methanol extract were used for in-vitro toxicity tests on Aeromonas sobria by disk diffusion and tube test. According to results in 200 and 400 mg/mL concentrations of ethanol extract of garlic, the inhibition zone of bacterial growth was 7 and 10 mm respectively. There was no inhibition zone for all concentrations of methanol extract of garlic. In water garlic extract the inhibition zone for concentrations of 100, 200 and 400 mg/mL were 8, 10 and 14 mm respectively. For 100% and 50% raw garlic the inhibition zone was 27 and 8 mm respectively. MIC for Aeromonas sobria in ethanol extract, water extract and raw garlic were estimated as 200, 100 mg/mL and 10% respectively. MBC for these extracts was also estimat-ed as 300, 100 mg/mL and 25% respectively. Our data indicate that raw and water extract of garlic have the highest antibacterial effect. Ethanol extract had a lower effect and methanol showed no bacteriostatic effect. Therefore, garlic extract can inhibit the growth of Aeromonas sobria, an important fish pathogen, and may have therapeutic value, particularly for carp.

Group A bovine rotavirus (BRV-A) is one of the most important causes of gastroenteritis and diarrhea in newborn calves. Major types of BRV-A in Tehran, Alborz and Qazvin were detected in this study. A total 125 fecal samples of calves showing clinical signs of diarrhea were collected from 26 industrial dairy farms located in the provinces of Tehran, Alborz and Qazvin, during two years. BRV-A was detected in 39.2 % (49/125) of total samples using a commercial ELISA kit. Thirty five positive samples were analyzed by seminested multiplex RT-PCR for P and G genotyping. G10 was the most prevalent genotype, accounting for 57.1% of samples, G6 accounted for 22.9% of samples and in 5.7% of samples (2/35), mixed infection of both genotypes G6 and G10 were detected. Also, the detected P types were P[11] and P[5], accounting for 71.4% and 14.2%, respectively. In our study, none of the genotypes G8 and P[1] were detected. The incidence of genotype combinations cor-responded to the B223-like strains (G10P[11]), UK-like strains (G6P[5]) and KN4-like strains (G6P[11]) were 51.4%,14.3% and 8.6%, respectively. Mixed infections G6/G10P[11] were detected in 2.85% of all samples analyzed with RT-PCR. To the best of our knowledge, this is the first report about the determination of P genotypes of BRV-A and distribution of the most common BRV-A strains circulating in Iran. Our study also indicated that the incidence of the G genotypes of BRV-A in the provinces of Tehran, Alborz and Qazvin, which is one of the greatest husbandry centers in Iran, has changed in the past years. Furthermore, this finding could be valuable in rotavirus vaccine design.

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. Importance of hilA mutation on S. enteritidis colonization and shedding in layer hens was evaluated in a long-term experiment. 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. 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. 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.

Poultry and poultry products are among the major sources of Salmonella infections for humans. Increasing occurrence of antimicrobial resistance among Salmonellae has become a serious public health concern. The detection of extended spectrum b-lactamase (ESBL) producers among Salmonella spp. has increased in recent years. The purpose of this study was to investigate the antibiotic resistance pattern of Salmonella, and to understand whether ESBLs were present in Salmonella isolated from poultry farms and slaughterhouses from various parts of Iran. A total of 314 isolates of Salmonella spp., 272 of poultry and 42 from human origin, collected during winter 2005-2011 were characterized for antimicrobial resistance and the presence of ESBL genes in this study. Phenotypic Disk diffusion method was performed for detection of anti-microbial susceptibility against 16 antimicrobial agents according to the Clinical and Laboratory Standards Institute's recom-mendations (CLSI, 2005). To detect the presence of ESBL genes in 30 isolates out of 61 phenotypical resistant isolates, PCR amplific-ation was used by employing specific primers for screening of the CTX-M and CMY groups, respectively. The highest resistance to ceforoxime in poultry and cefixime in human isolates was observed, and multidrug resistance (MDR) was seen with a maximum seven antimicrobial agents. The PCR detection of CTX-M and CMY genes in all isolates including five phenotypically ESBL positive isolates was negative. This study revealed the incidence of resistance to cephalosporins and the frequency of MDR among Salmonella isolates from poultry farms in Iran. The prevalence of MDR Salmonella isolates from poultry are of particular concern as these strains can transmit to humans through the food chain

Broilers lung mechanisms that regulate endothelin (ET) in the lung are complex and poorly understood. Objectives/ 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. 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. 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).

Propolis, a honeybee product, has been used empirically for centuries and was always mentioned as an immunomodulatory. In this study, the effects of propolis on growth indices, innate immune responses and haematological parameters of Barbus barbulus were investigated. Three hundred and sixty juvenile Barbus barbulus, weighing 102±8.2g were randomly divided into four equal groups in triplicate. Groups 1 to 3 were fed basal food supplemented with 0.1, 0.5, 1% of Propolis-ethanolic -extract (PEE) in diet for 60 days. Control group received basal diet free of PEE. At the end of experiment, growth indices were measured in all groups. Various immunological parameters (serum lysozymme and bactericidal activity, complement activity, total serum protein and globulin) as well as hematological parameters (RBC, WBC, hemoglobin, hematocrit, MCV, MCH and MCHC) of Barbus barbulus were compared among the groups. Then the fish were challenged with Aeromonas hydrophila. Oral administration of different level of PEE induce no significant change, neither in growth indices nor in haematological parameters of B. barbulus (p>0.05). Significant increase in serum Lysozyme and bactericidal activity, total serum protein and WBC were seen in G2 and G3 compared to the control group (p<0.05). Meanwhile, mortality after challenge of fish fed on diet containing 0.5% PPE significantly decreased compared to control group. It was concluded that, although supplementation of food with 0.5 and 1% PEE enhanced some immune response indicators of B.barbulus, growth indices and hematological parameters were not affected by this supplementation.

Nowadays, Microencapsulation of probiotic bacteria is the newest method for increasing the survival ability of probiotics in Food products. The Lactobacillus acidophilus as a probiotic bacterium has more beneficial effects and the low survival of this bacterium under food processing conditions and adverse environment have been studied by many researchers. In this study, Lactobacillus acidophilus was added to mayonnaise sauce as either free cells or encapsulated and the survival of probiotic was evaluated during storage for 30 days at 4oC. The emulsion method was performed for the microencapsulation process of Lactobacillus acidophilus. A morphological characteristic of capsules was indicated by optical microscope and scanning electron microscope. The microencapsulation with calcium alginate-resistant starch significantly affected (p<0.05) the survival of Lactobacillus acidophilus compared to free state in mayonnaise sauce. No differences were detectable in the morphological of capsules with resistant starch by scanning electron microscope and Sensory properties of mayonnaise sauce were improved by the addition of encapsulated Lactobacillus acidophilus. The microencapsulation significantly increased the survival of Lactobacillus acidophilus.

Probiotics and especially Lactobacilli are among the most important components widely used in food technology. Isolation and characterization of indigenous probiotics should be performed in native populations. In order to isolate lactobacillus spp. from Iranian traditional Lighvan cheese to be used as starters, 15 cheese samples were randomly selected and tested for technological and probiotics properties. Lactobacilli were characterized using culture-based and bio-chemical techniques and results were verified using PCR analyses of the 16S rRNA region. The probiotic characteristics of these bacteria were studied by acid and bile tolerance. The susceptibility of different isolates against a number of important antibiotics was tested. The technological traits of LAB were assessed using measurement of acid production and analyzing salt tolerance. The isolates were also screened for proteolytic and lipolytic activity. Of the 12 samples containing Lactobacilli, 10 belonged to L. plantarum while 2 were close to L. bulgaricus spp. All isolates were tolerant to 3% NaCl and 9 tolerated 6-8% NaCl. Almost all isolates were lipase-positive at 37 °C and 30 °C. Nine Lactobacilli were shown to be protease-positive at 37°C. Two isolates were completely tolerant to pH 1.55, 4 had intermediate resistance, 4 were of weak resistance and 1 was sensitive. All but one isolate were tolerant to 0.03% bile acid. Some isolates were shown to be sensitive to erythromycin, ampicillin, tetracycline, amikacin and rifampicin. Results indicate that most of the isolated Lactobacilli can be used as industrial cheese starters and/or as native probiotics in production of functional foods.

An adult common mynah (Acridotheres tristis) was presented with severe signs of progressive depression, anorexia, debilitation, and also a history of moderate pododermatitis for the last two months. Hepatomegally was diagnosed clinically and radio-logically. The bird died a couple of hours after referral. Postmortem examination revealed typical liver enlargement with yellowish brown discoloration. Diffused hepatocytes fatty degeneration was demonstrated in histopathology and hepatic lipidosis was diagnosed as the main lesion in the liver. Providing a very small enclosure and a single low quality perch with minimal activity opportunity led to pododermatitis. Subsequent further activity restriction and feeding a high energy diet to the bird were possibly the triggers of this metabolic disorder. Regarding the bird species, providing appropriate diet and enclosure are essential for having healthy pet birds, and is often ignored by negligent or uninformed owners.