BACKGROUND: Subclinical mastitis plays an important role in the economic losses of dairy cattle farms. Staphylococcus aureus is one of the most important causes of this disease. Treatment of this disease with synthetic antibiotics has complications like antibiotic resistance. Using herbal antibiotics can be an excellent way to reduce these side effects.OBJECTIVES: This study aimed to determine the minimum inhibitory concentration of alcoholic extract of olive leaf on Staphylococcus aureus isolated from milk of cows with subclinical mastitis to achieve herbal treatment.METHODS: This study was conducted on 175 Holstein female cattle. The milk samples of 60 cows were obtained with the sterilized method, and Subclinical mastitis-positive cases were determined using the California mastitis test. Staphylococcus aureus bacteria were isolated from positive samples by culture method, and the minimum inhibitory concentration of olive (Olea europaea L.) leaves alcoholic extract on isolated bacteria was determined by microdilution method.RESULTS: From 175 cows under study, 60 cows had a positive California mastitis test, and Staphylococcus aureus separated from milk samples of 14 cows. The minimum inhibitory concentration of olive (Olea europaea L.) leaves extract on this bacterium was 12000 ppm.CONCLUSIONS: Alcoholic extract of olive (Olea europaea L.) leaves has an antimicrobial effect on Staphylococcus aureus as a cause of mastitis. The minimum concentration required for this effect was 12000 ppm. Further studies on the impact of this plant on other bacterial causes of subclinical mammary inflammation in cows and investigation of the effective substances in the extract are needed.

BACKGROUND: Storing semen at a temperature of 4 degrees Celsius reduces its motility and quality.OBJECTIVES: This study aimed to determine the effect of adding calcium compounds, including calcimaphor (CMP), calcium gluconate (CG), and calcium chloride (CaCl2), on the motility and progressive motility of rooster sperm kept at refrigerator temperature.METHODS: This research used five pieces of 45-week-old Lari breed roosters. The liquid diluent added different calcium compounds at 0.56, 0.056, and 0.0056 mM concentrations. After treatment, the diluted seminal samples were cooled at the storage temperature to avoid thermal doubt and then transferred to the refrigerator at 4 degrees Celsius. Parametric factors that were more important such as the percentage of laterality and progressive mobility, were measured visually using the lens of a 40-light microscope, survival was checked using the eosin-nigrosin staining method, acrosome health percentage by formalin citrate method, cell membrane health with hypoosmotic test, lipid peroxidation level, fertility was evaluated using perivitelline membrane sperm reaction 72 hours after storing at 4 degrees Celsius.RESULTS: Based on the results, different calcium compounds in most concentrations could significantly affect the parameters of survival, mobility, and progressive mobility (P<0.05).CONCLUSIONS: Most of the sperm-related parameters in the control group decreased after this period of storage in the refrigerator, but the addition of calcium gluconate (0.56, 0.056, and 0.0056), Calcimaphor (0.56, 0.056, and 0.0056) and calcium chloride (0.56, 0.056 and 0.0056) to the semen thinner maintained the quality indicators of rooster sperm.

BACKGROUND: The pollution of environment with heavy metals following the increase in the industrial production has created problems in the lives of living organisms. Lead can penetrate the soft organs of body, and by depositing in them can cause disorders their function. Lead can cross the blood-placental barrier and transfer to the fetus. It is also possible to pass lead through milk to the newborn.OBJECTIVES: The stereology approach was used in rats as animal models to examine the impact of low dosage lead contamination in the mother on the average volume of follicular oocytes and the average volume of mature follicles.METHODS: Wistar rats were randomly divided into five groups, which included a control group and four experimental groups of pre-pregnancy, pregnancy, lactation and pre-pregnancy-pregnancy-lactation. The control group had access to drinking water with 0.5 ml of glacial acetic acid. Experimental groups administered lead acetate at a rate of 0.2 percentage + 0.5 ml of glacial acetic acid through drinking water in different periods (pre-pregnancy group 30 days before mating, pregnancy group 21 days of pregnancy, lactation group. They received 21 days of lactation and the pre-pregnancy-pregnancy-lactation group 30 days before mating until the end of lactation). On the 65th day after birth, all infants were killed in the laboratory and left ovary specimens were collected for stereological studies.RESULTS: The results showed that the average volume of oocytes in the primordial, monolayer primary, multilayer primary, and antral follicles increased in the lactation group compared to the control group and other experimental groups (P<0.05). Furthermore, the mean volume of primordial and monolayer primary follicles in lactation group increased compared to the control and experimental groups (P<0.05).CONCLUSIONS: This study's results showed that maternal exposure to low doses of lead during lactation increases the average volume of oocytes and increases the average volume of growing follicles.

BACKGROUND: Gallibacterium anatis is a recently defined genus, which is a member of the Pasteurellaceae family. This advantageous pathogen is frequently found as part of the normal microflora of the upper respiratory tract and lower genital tract of the healthy poultry. Provided with appropriate conditions, it leads to various diseases, such as salpingitis, peritonitis, and loss of egg production with mortality in layer flocks. According to previous studies, multiple antibiotic resistance has been observed among G. anatis isolates, which can impose high costs on layer flocks. Due to the lack of the pathognomonic symptoms in the conflicts caused by this bacterium,  not enough comprehensive research has been conducted to date on the condition of this disease in Iran.OBJECTIVES: This study aimed to investigate the infection rates of this bacterium via PCR.METHODS: 295 tracheal swabs were collected from 10-layer flocks. Subsequently, the suspected colonies were isolated and identified with morphological features, differential cultivation, and PCR.RESULTS: 43.72 % of the samples were positive.CONCLUSIONS: The results of this study indicated that laying farms in Iran were infected with Gallibacterium anatis; thus, certain measures should be taken to control the factors reducing the production of layer flocks.

BACKGROUND: Corynebacterium pseudotuberculosis and Trueperella pyogenes are two important pyogenic bacteria that cause many annual economic losses worldwide. Currently, antibiotic resistance of these bacteria is on the rise. Early detection of infection with these bacteria is important for controlling the infections caused by these two bacteria.OBJECTIVES: This study aimed to investigate the contamination of cattle cutaneous abscesses with  Corynebacterium pseudotuberculosis and Trueperella pyogenes in five large cattle farms around Tehran and propose an accurate method for a rapid detection of these two bacteria.METHODS: Out of 60 cows involved in cutaneous abscesses in the summer of 2018, sterile sampling was performed to diagnose the bacterial agent that caused the abscess. Bacteriological examination of the samples was performed using standard biochemical reactions and polymerase chain reaction using specific primers.RESULTS: Of the 60 samples studied, 25 % (15.60) were isolated as Corynebacterium pseudotuberculosis and 20 % (12.60) as Trueperella pyogenes. In 55 % of the samples (33.60), both bacteria were present simultaneously. All the samples detected using biochemical reactions were confirmed by the polymerase chain reaction.CONCLUSIONS: Corynebacterium pseudotuberculosis and Trueperella pyogenes are the main causes of cutaneous abscess in cattle farms around Tehran. Because the accurate diagnosis of the cause of abscesses is very important for effective treatment, polymerase chain reaction, based on 16S-23S rDNA and 16S rRNA, can be used to rapidly and accurately detect these bacteria in the early stages of the infection.

BACKGROUND: Reducing the protein and amino acid content of diet or altering the dietary electrolyte balance were suggested as the effective strategies to prevent the harmful effects of the heat stress in poultry.OBJECTIVES: This study surveyed the effects of various levels of threonine and dietary cation-anion balance on the broiler chickens under the heat stress conditions.METHODS: 700 one-day-old male broilers (Ross 308) were used for 6 weeks under high- temperature conditions. This experiment was conducted using a 2 × 3 + 1 factorial experiment based on a completely randomized design, with 7 treatments (5 replicates per treatment and 20 birds per replicate). Experimental factors included two threonine concentrations (recommended level and 10 % above recommended level) and three dietary electrolyte balances (175, 250, and 325 mEq/kg). The control group considered the treatment with a normal threonine concentration (recommended level) and a dietary electrolyte balance of 250 mEq/kg under optimal temperature conditions.RESULTS: Although there was no interaction between threonine level and electrolyte balance, the electrolyte balance of 175 meq/kg increased the performance index compared to the electrolyte balance of 250 or 325 mEq/kg (P<0.05). The villus height to crypt depth ratio and villus surface area in the jejunum improved with an electrolyte balance of 175 or 250 mEq/kg (P<0.05). A decrease in the dietary electrolyte balance increased in the nitrogen-corrected apparent metabolizable energy (P<0.05). Besides, an increase in the population of lactobacilli and bifidobacteria in the cecum, as well as an increase in protein digestibility, were observed by increasing levels of threonine in the diet (P<0.05).CONCLUSIONS: Based on these results, a high level of threonine or a low electrolyte balance in diet (175 mEq/kg) may improve the performance, metabolizable energy, and intestinal microbial flora of broilers reared under heat stress.

BACKGROUND: Stocking density is one of the most important problems in the poultry industry, which impair their production and welfare.OBJECTIVES: This experiment was done to evaluate the effect of organic selenium supplementation on the growth performance, blood metabolites, and the meat quality of broiler chickens in different stocking densities.METHODS: 216 one-day-old male broiler chickens (Ross 308) were used in 2×2 factorial arrangements by 2 stocking densities (7 and 15 birds/m2) and 2 levels of selenomethionine (0 and 0.4 mg/kg) in a completely randomized design with 4 treatments and 4 replicates.RESULTS: The feed intake (FI), and body weight gain (BWG) were significantly affected by the stocking density and selenomethionine (SE-MET) supplementation in the overall experiment (P<0.05). FI and BWG decreased and feed conversion ratio decreased in 15 bird’s density, while SE-MET inclusion improved these traits (P<0.05). Increasing stocking density increased the plasma glucose (P<0.05). Blood glutathione peroxidase and lymphocyte levels reduced at 15 bird’s density, while increased by 0.4 mg SE-MET supplementation (P<0.05). Increasing stocking density increased blood heterophil, while SE-MET inclusion decreased it (P<0.05). Meat pH and cooking loss were not affected by stocking density. Dripping loss (DL) increased, and water holding capacity (WHC) decreased at 15 bird’s density, but 0.4 mg SE-MET decreased DL and significantly increased WHC (P<0.05).CONCLUSIONS: It was concluded that increasing stocking density had the negative effects on the growth performance and meat quality of broiler chickens; however, the supplementation of 0.4 mg of SE-MET to diet can improve the growth performance, blood metabolites and meat quality of broiler chickens.

BACKGROUND: Blowfly (Lucilia sericata; Diptera: Calliphoridae) is an external parasites of domestic animals and the causative agent of myiasis, which is involved in the transmission of a  number of bacterial pathogens. Application of chemical insecticides is one of the most common methods for controlling this pest, which have recently been reported resistant populations of L. sericata to some insecticides. Therefore, identifying and recommending new and low-risk insecticides for humans and environment is of prime importance.OBJECTIVES: This research aimed to investigate the toxicity of insecticides deltamethrin, spinosad, pyridalyl, and pirimiphos-methyl on the third instar larvae of L. sericata.METHODS: In the present study, the bioassay tests were performed by immersion of larvae in concentrations of insecticides that caused 10 to 90% mortality of larvae, as a factorial experiment in a randomized complete block design. Additionally, the median lethal concentration (LC50)  was determined from the probit analysis of bioassay data for the studied insecticides.RESULTS: The results of analysis of variance and the comparison of the mean mortality (%) of third instar larvae were significant at the level of 1% probability. According to bioassay tests, the estimated LC50 values for deltamethrin, spinosad, pyridalyl, and pirimiphos-methyl were 186.49, 26.88, 85.08, and 134.97 mg L-1, respectively. Overall, the results revealed that spinosad and pyridalyl had the highest lethal effect on blowfly larvae while deltamethrin had less advers effects on this pest.CONCLUSIONS: Spinosad, as a relatively new insecticide, with very low toxicity towards mammals and other non-target organisms, showed the highest lethal effect on blowfly larvae and can be an appropriate alternative to older insecticides in controlling this pest.

BACKGROUND: Homocysteine (Hcy) is a sulfur-containing amino acid derived from methionine. Several studies have suggested that plasma Hcy may be a useful biomarker of cardiovascular disease in human. There is limited information about serum homocysteine in heart diseases of dogs.OBJECTIVES: The present study aimed to assess the concentration of serum total Hcy and evaluate the relationship between its concentrations and serum levels of cholesterol, triglycerides, and activities of creatine phosphokinase and aspartate aminotransferase in small breed of dogs with endocardiosis.METHODS: For this purpose, a total of 15 dogs (seven males and eight females) with acquired endocardiosis were confirmed by clinical examination, auscultation, thoracic radiography, and echocardiography. In addition, 15 normal dogs of the similar age, breed, and weight were selected as the controls. All the examinations performed on the patients were carried out on the healthy dogs. Homocysteine was measured via an enzymatic method. Additionally, the activities of CPK and AST and the levels of cholesterol and triglycerides were assessed utiling commercial kits. Subsequently, the data were analyzed with t- student test and one- way ANOVA and Pearson’s linear correlation test was used to determine the relationship between serum homocysteine levels with triglycerides, cholesterol, CPK, and AST.RESULTS: The results revealed no significant differences concerning serum homocysteine level and AST activity between the two groups; meanwhile, the increase in serum triglycerides and CPK activities in dogs with heart disease was statistically significant compared to that in the control group. However, there was no significant correlation between homocysteine and the other measured parameters.CONCLUSIONS: The present study indicated that the role of homocysteine as a new risk factor associated with dog endocardiosis is questionable and it seems as if in human studies related to homocysteine and heart disease, the selection of dog as animal model requires further investigation.

BACKGROUND: Oxidative stress is believed to be one of the major causes of tissue damage in aquatic animals exposed to heavy metals. It leads to certain changes in the antioxidant and enzyme system. Given the fact that research on the effect of sub-acute toxicity of silver nitrate in shrimps is not very developed, the present study can be conducive to formulating the international standards of contamination of shrimps with silver nitrate.OBJECTIVES: The present study aimed to evaluate the toxic effects of silver nitrate on the changes in the antioxidant and enzyme systems of hepatopancreas, muscle and gills of Litopenaeus vannamei.METHODS: After acclimatization of shrimps, they were exposed to silver nitrate with concentrations of 0.0084, 0.021, 0.042 and 0.063 mg/L for 21 days. At the end of the experimental period, gill, muscle and hepatopancreas were sampled, and the changes in the antioxidant system (SOD, GPx and GST) and metabolic enzymes (ALT, ALP, AST and LDH) were examined.RESULTS: There was no significant difference in terms of SOD and GST activity in the gill and muscle of the exposed shrimps (P>0.05). However, GPx in treatment 4 increased significantly in gill and muscle while it saw a decrease in hepatopancreas (P<0.05). In hepatopancreas, GST significantly increased in treatments 3 and 4 (P<0.05) whereas SOD did not show any significant changes compared with other treatments (P>0.05). The metabolic enzymes of the muscle did not show any significant differences in any of the treatments (P>0.05), but in gill, the level of ALT in treatment 4 decreased significantly while the levels of AST and LDH in treatment 3 and 4 significantly increased (P<0.05). In hepatopancreas, the activity of ALT in treatments 2 and 4, AST in treatments 3 and 4, and ALP in all treatment except treatment 1 saw significant reduction. Nevertheless, LDH in treatments 3 and 4 had a significant rise (P<0.05).CONCLUSIONS: A significant increase in GST and LDH as well as a significant decrease in GPx and ALT, AST and ALP enzymes in the hepatopancreas revealed that the antioxidant and enzyme system of shrimps is further disturbed with the rise in silver nitrate concentration in the hepatopancreas compared to the gill and muscle.