BACKGROUND: Omega-3 fatty acids can be conducive toreducing the harmful effects of physiological stress through reducing the stimulatory activity of glutamatergic neurons.OBJECTIVES: The aim of this study was to investigate the effects of omega-3 fatty acids on performance, blood parameters, and the profile of fatty acids in the egg yolks of laying hen under stress.METHODS: This study was performed using 96 LSL-Lite laying hens in a 2 × 3 factorial experiment with 2 factors, namely stress (no dexamethasone and 1.5 mg/kg of diet dexamethasone) and omega-3 fatty acids (the levels of 0, 0.24 and 0.48 % of diet), in a completely randomized design for 70 days from 35 to 44 weeks of age.RESULTS: Physiological stress reduced the feed intake, the percentage of egg production, and egg mass in laying hens (P<0.05). Omega-3 fatty acid supplements had no effects on these traits. The groups receiving 0.48 % of omega-3 fatty acids had the lowest heterophil:lymphocytes (P<0.05), and there was no difference between stressed and non-stressed groups. The ratio of omega-6 to omega-3 fatty acids was higher in birds previously affected by stress (P<0.05). Feeding with omega-3 fatty acids in birds increased omega-3 fatty acids in egg yolk and reduced the ratio of omega-6 fatty acids to omega-3 in laying hens (P<0.05).CONCLUSIONS: Based on the results of this experiment, physiological stress had a negative effect on performance traits, and the use of omega-3 fatty acids in laying hens under stress had no effect on performance traits. Physiological stress altered the profile of fatty acids and increased the proportion of omega-6 to omega-3 fatty acids in egg yolk. The use of omega-3 fatty acids reduced the negative effects of stress and improved the profile of fatty acids in egg yolk.

BACKGROUND: Thyme extract has the antimicrobial and antioxidant components that can be useful for the broilers under heat stress condition. OBJECTIVES: This experiment was conducted to investigate the effects of Thymus vulgaris extract in comparison with some common feed additives on performance, blood biochemical parameters and antibody response in broiler chickens under heat stress conditions. METHODS: This study was conducted using 192 one-day-old male broiler chicks (Ross 308) in a completely randomized design with 8 treatments in 4 replicates and 6 chicks per replicate. Treatments were as follows: 1) basal diet + standard temperature conditions (positive control); 2) basal diet + heat stress conditions (negative control); 3) negative control + 200 mg virginiamycin; 4) negative control + 150 mg Protoxin probiotic, 5) negative control + 250 mg vitamin C, 6) negative control + 250 mg vitamin E, 7) negative control + 250 mg thyme extract, and 8) negative control +500 mg thyme extract per kg diet. RESULTS: Dietary thyme extract at the rate of 500 mg/kg as well as probiotic and vitamin E increased (P<0.05) body weight gain (2202, 2183 and 2199, respectively) and improved feed conversion (1.65, 1.74 and 1.66, respectively) compared with negative control group (body weight gain 1960 g and feed conversion ratio 1.96). Moreover, 500 mg/kg dietary thyme extract, probiotic and vitamin C reduced triglycerides, total cholesterol and low density lipoprotein during heat stress conditions (P<0.05). All dietary supplements groups significantly increased antibody titers against red blood cells as compared with negative control. CONCLUSIONS: In general, the results of the present study suggest that thyme extract at the level of 500 mg/kg of diet can be recommended as an alternative to the common feed additives to improve growth performance and health benefits of the heat-stressed broilers.

BACKGROUND: Cheese is a dairy product that is popular in the world. Prebiotics and probiotics are increasingly being used to produce potentially symbiotic foods, particularly through dairy products as vehicle. It is well known that both ingredients may offer benefits to improve host health. OBJECTIVES: In this study prebiotic effect of Olive leaf extract or survival of Lactobacillus casei in UF cheese production during 10 weeks storage in cold condition was researched. METHODS: After provision of aqueous extract of olive leaf, probiotic bacteria and starter culture were prepared for inoculation. This extract was added to UF cheese in the presence of the bacteria then, counting of L.Casei on MRS-bile agar with pour plate was done during 10 weeks of storage and sensory evaluation was performed after 10 weeks of cheese storage at 4 °C. RESULTS: The number of L. Casei was affected significantly by the addition of OLE (P<0.05). The bacterial growth had a significant relationship with the increase in OLE concentrations (P< 0.05). After 10 weeks, in all probiotic cheese, the concentration of L. Casei was at the level of 106 - 108 cfu/g. Also, sensory quality was positively affected by the presence of OLE in cheese samples. Cheese sample produced with the addition of 0.5% of OLE was the most desirable. CONCLUSIONS: The number of Lactobacillus casei was significantly increased during the storage weeks due to the addition of different concentrations of olive leaf extract. The number of probiotic was increased with increasing concentrations of the extract (P<0.05). Also, positive effects on the sensory properties of cheese samples affected by olive leaf extract were observed and the most common cheese sample was 0.5% of this extract.

BACKGROUND: Staphylococcus aureus is one of the most important human pathogens that cause infection and also food intoxication by secreting various enterotoxins. Conventional culturing methods to detect S. aureus have some limitations such as being time-consuming due to bacterial growth and low precision and sensitivity in detecting viable but non-cultivable cells. OBJECTIVES: The objective of this study was to detect and quantify enterotoxigenic (A-E) S. aureus in cream pastry products applying PCR coupling with propidium monoazide (PMA) to distinguish dead and live cells. METHODS: One hundred samples were randomly collected from pastry shops in Amol, in a period of 2 months. After preparing dilutions, bacterial pellets were separated and treated with PMA before DNA extraction. Real time PCR was conducted in order to quantify S.aureus cells and enterotoxigenic strains using specific primers. RESULTS: Results of conventional method were close to PMA-qPCR data (P>0.05), but data from qPCR that includes live and dead cells shows more bacterial count than two other methods. Sensitivity of the method applied in the present study, detecting low number of S.aureus cells (less than 10/g) seems considerable. CONCLUSIONS: Findings showed that applying PCR coupling with PMA results in more reliable data than conventional culturing method. Regarding this approach being time-effective, considerably sensitive and specific, it is expected that it be used in food quality control labs in monitoring systems in future.

BACKGROUND: Diarrhea syndrome is associated with irrecoverable damages in the husbandry industry worldwide due to losses resulted from fatality, weight loss, growing weak calves and treatment costs. Hence, investigation of diarrhea causes in different areas is important to attempt management strategies to prevent and control it. OBJECTIVES: Present study was carried to investigate prevalence of some important entropathogens in diarrheic calves until three months old, in Shahrekord suburb husbandries. METHODS: Fecal samples were taken from 82 female calves in first day of diarrhea and were examined for isolation of salmonella, Escherichia coli, clostridium, cryptosporidium, and coccidia through common microbiological and parasitological methods. RESULTS: In general, prevalence of isolated organisms were: salmonella 36.6%, Escherichia coli 24.4%, clostridium 9.8%, cryptosporidium 9.8%, and coccidian 7.31%, and Escherichia coli K99 were isolated from four calves. The most prevalent pathogens were Escherichia coli and Salmonella. CONCLUSIONS: The calves are unavoidably exposed to infectious causes of diarrhea during their whole lifespan, because they acquire organisms from environment immediately after birth. Therefore, attempts at efficient management methods, hygienic principles and receiving enough colostrum, particularly in cold seasons, may be efficient in the control, prevention and decrease of diarrhea and its subsequent losses.

BACKGROUND: Rotavirus Group A is one of the most important causes of gastroenteritis as it is isolated from 30 to 50% of infant diarrhea from humans and other animals. G genotype of the virus is determined by gene sequence of a surface protein of the virus (VP7), one of the most important factors in inducing immunity against the virus which acts very specific to each genotype. OBJECTIVES: In the present study the presence of common bovine rotavirus genotypes A was examined in human rotavirus population. METHODS: A total of 100 stool samples from children under 2 years of age in Tehran and Varamin were collected and to track the presence of rotavirus A, were evaluated using ELISA method. Positive samples were isolated and cultured on the MA-104 cell line after several passages. The positive samples (49 samples) were determined to be the G type using semi-nested RT-PCR and primers specific for bovine common genotype. RESULTS: From 100 samples, 49 were positive in ELISA. Eight samples in the first semi nested RT-PCR showed the desired rotavirus bands and in the second round, the results were positive for the presence of bovine VP7 in two samples taken from Varamin, in one sample, G6, and in another sample, two genotypes of VP7, G6 and G8 were detected, indicating infection with at least two strains of human rotavirus reassortant. Six of the ELISA selected positive samples that were taken to the cell line MA104, showed effects of cell damage (CPE) after 4-5 consecutive passages, demonstrating proliferation of the rotaviruses of this study and so, their viability was confirmed. CONCLUSIONS: The results of this study indicate reassortment between bovine and human rotaviruses and show that in case of occurrence of bovine and human rotavirus infection and the emergence of new human type, due to reassortment strain differences in protein immunogen it is possible to overcome due to lack of maternal immunity in the human population and low efficiency of current vaccines and, ultimately, epidemic and considerable losses may occur. Hence, more research is warranted.

BACKGROUND: Toxoplasma gondii is an intracellular protozoan parasite that can infect most species of warm-blooded animals, including birds and humans. Because of feeding habits of domestic chickens, prevalence of Toxoplasma infection in free-range chickens is considered as a suitable indicator of environmental distribution of oocysts. OBJECTIVES: The present study was designed to investigate the seroprevalence of Toxoplasma infection in domestic chickens from Khorramabad and compare the results obtained from serological and molecular methods. METHODS: In total, 97 serum samples were randomly obtained from domestic chickens and examined for the presence of anti-Toxoplasmaantibodies using modified agglutination test (MAT). Fifty grams of muscles (mixture of breast and heart) and whole brain from seropositive chickens were separately homogenized and examined by PCR which targets the repeated element (RE) of the parasite. RESULTS: Anti-Toxoplasma antibodies were observed in 21 of 97 (21.64%) sera. T. gondii DNA was detected in 10 out of 21 (47.61%) seropositive chickens (with titres of ≥1:20). The low agreement between serological and molecular results can be explained by several factors such as possibility of cross-reactions in MAT and/or limited sample size in PCR. CONCLUSIONS: These results indicate that domestic chickens may have an important role as a source of infection for cats and individuals living in rural areas.

BACKGROUND: Ticks are one of the most important ectoparasites in animals that cause economic losses in livestock industry. So, removal or reduction of ticks on animals is necessary. Cysteine proteases are among the compounds that play an important role in the physiological action of ticks and are a good candidate for the anti-tick vaccine. Cathepsins is one of the most important cysteine proteases. OBJECTIVES: The aim of this study was cloning and expression of recombinant cathepsin L gene of Rhipicephalus annulatus in order to evaluate its immunogenicity. METHODS: After collection the ticks were cultivated. Then RNA was extracted from ticks, cDNA was synthesized by using specific primer of cathepsin and amplification by RT-PCR. The desired genes were cloned into expressional pQE30 plasmid. Further, a shorter sequence of the cathepsin gene (654 bp) was prepared as a synthetic plasmid. The expression of the protein produced by both recombinant plasmids in the E.coliBL21 prokaryotic expression system is carried out and the immunity of the recombinant proteins was evaluated by Dot Blot and Western Blot using serum of challenged rabbits with recombinant protein and calves infected with ticks were examined and compared. RESULTS: The results of this study indicate that the protein derived from recombinant plasmid No. 2 had higher expression and purity due to its solubility. Also, the challenge of rabbit serum with these proteins was able to identify both recombinant proteins. But the serum of challenged calves with ticks did not show a satisfactory response with recombinant proteins. CONCLUSIONS: Although the sera reaction of calves infested with ticks was lower than the challenged rabbits sera with cathepsin L, this result was expected, because L cathepsin protein is considered as a concealed antigen.  Overall, the recombinant cathepsin L could be an appropriate candidate for immunizing calves against Rhipicephalus annulatus, although it seems further investigations are necessary.

BACKGROUND: The protozoancryptosporidiumisan important intestinal parasitic infection in domestic ruminants that has the potential for transmission between humans and livestock throughout the world and Iran. OBJECTIVES: The present study was undertaken to determine cryptosporidiuminfection in different age groupsof cattle and water buffaloesin farms of Mahabad suburb, Iran. METHODS: For this purpose, a total number of 248 fresh fecal samples were randomly collected from rectum of cattle and water buffaloesin farms of 4 villages from May2016 to May 2017. The fecal samples were subjected to floatation technique andcryptosporidiumoocysts were collected using Sucrose Gradient and Percole flotation technique and stained with modified Ziehl-Neelsen technique. RESULTS: Overall prevalence of cryptosporidiuminfection was 50% (124/248). The highest rate of infection was significant in female calves (30.65%) less than one year-old. The highest infection rate was significantly found in summer (20.16%). Cryptosporidium parvum and C. andersoni were identified in 40.32% (100/248) and 9.68% (24/248) of examined cattle, respectively. Mixed infection was 8.47%. CONCLUSIONS: The results of this study indicated that C.parvum was prevalent in cattle of the region, therefore, further molecular studies are recommended to determine the genotypes of the parasiteas a potential zoonotic agent.

BACKGROUND: This study was conducted to characterize two fowlpox viruses isolated in Iran and study their phylogenic relationship. OBJECTIVES: The aim of this study was to determine the identity of two pox viruses recovered from a tissue sample with typical lesions of fowl pox and red mites from a laying farm. Fowl pox in poultry industry causes significant economic losses associated with decreased egg production, reduced growth, blindness and increased mortality. The pox virus, by direct or indirect contact, may also be transmitted through vectors such as mites and fleas. Dermanyssus gallinae also known as the poultry red mite is the most important blood feeder ectoparasite affecting poultry, in particular, laying hens. In addition to its significant economic losses, it is considered as a potential vector for a number of important avian pathogens. METHODS: Both isolates were inoculated to chorioallantoic membrane (CAM) of embryonated chicken eggs, detected by specific PCR for pox virus 4b gene and characterized by sequencing and phylogentic analysis. RESULTS: Both isolates developed pock lesions in CAM of embryonated eggs. A 578 bp fragment of the poxvirus 4b gene was amplified in both isolates by PCR. The sequence analyses revealed that the two isolates were 100% identical and placed in the same branch. The nucleotide sequence of these two isolates showed a similarity of 73 to 100% to the other selected avian pox sequences available in the GenBank. CONCLUSIONS: These results confirmed that Dermanyssus gallinae are considered to be an important vector for the spread of fowl pox virus in the flocks. Therefore, controlling the red mites in poultry farms will not only inhibit problems such as blood feeding, decreased production and reduced growth rate, it can reduce the transmission of diseases and pathogenic agents in the farms.