BACKGROUND: Nucleotides (NT) are known as semi- or conditionally essential nutrients which might occasionally become essential in pathological and stress conditions that demand intense nucleic acid and protein synthesis.OBJECTIVES: A feeding trial was conducted to evaluate the effects of NT supplementation on growth performance and stress resistance of fry kutum (Rutilus kutum).METHODS: A basal diet was supplemented with 0 (control), 0.3, 0.5, and 0.7 g NT kg-1 to formulate four experimental diets. After eight weeks of feeding trial, the growth parameters were evaluated and then fish exposed to osmotic stress. To elucidate the underlying physiological mechanisms, cortisol and HSP70 levels were measured at selected times of 0, 2h, 8h, and 24h after the osmotic shock.RESULTS: According to the results of growth parameters after eight weeks of feeding trial, fish fed diet with 0.7 g NT kg-1 had the highest final weight and DGR compared with the other treatments (P<0.05). However, no significant differences were observed concerning FCR, SGR, CF, and PER between the treatments (P>0.05). The results of HSP70 revealed that fish fed with NT had higher levels of HSP70 expression. Additionally, the levels of HSP70 at 2h increased significantly by 3-7-folds over the baseline levels (0h), and then decreased significantly at 24h; however, HSP70 levels at 24h was 1-3-fold over the baseline levels. The findings of cortisol showed that Cortisol values were significantly affected by dietary NT levels (P<0.05) and lower stress-induced cortisol and glucose elevation were observed in all the NT groups compared to the control group. Moreover, plasma cortisol levels reached a significant peak 2h after the salinity stress. This value decreased significantly after 8h, returning to the pre-stress levels by 24h (P>0.05).CONCLUSIONS: Our data indicated that NT administration promoted growth performance and increased the ability of resistance to osmotic stress during freshwater to seawater transfer in fry kutum.

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: 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.

BACKGROUND: Vanadium and zinc are identified as low-concentration elements in the body of living organisms with a wide range of activities. Their insulin-like activity, through regulating the metabolism of carbohydrates, lipids, and eliminating the secondary symptoms of the disease, clearly demonstrates the ability of these elements to improve diabetes.OBJECTIVES: The present study aimed to evaluate the effect of vanadium-zinc complex on the structural, functional, and oxidative stress changes in liver tissue in adult diabetic male rats.METHODS: Herein, we recruited 40 adult male rats with the same weight range. They were randomly divided into four groups of 10, namely control, diabetic, healthy mice receiving vanadium-zinc complex, diabetic mice receiving vanadium-zinc complex) and received this combination at the rate of 10 mg / kg once a day for 60 days by oral gavage. At the end of the course, following blood sampling, part of the liver tissue was removed from the body to measure oxidative stress and the rest for stereological and histological studies. The serum isolated from the animals was also used to measure liver tissue functional enzymes (aspartate aminotransferase, alkaline phosphatase, alanine aminotransferase).RESULTS: The results of this research revealed that vanadium-zinc complex has no side effects on liver tissue in most case, but can greatly prevent structural damage to liver tissue by lowering blood glucose levels in diabetic rats and improving oxidative stress.CONCLUSIONS: Vanadium-zinc complex can be utilized with a certain mechanism in order to control blood sugar and inhibit oxidative stress. It could be regarded as an appropriate approach to preventing liver damage following chronic hyperglycemia in diabetic patients.

BACKGROUND: Major histocompatibility complex (MHC) encodes for highly variable molecules, most of which are responsible for foreign antigen recognition and activation of immune responses in the host. LEI0258 microsatellite, located in the poultry MHC region, is a suitable genetic marker for determining MHC haplotypes and genetic diversity in poultry.OBJECTIVES: Considering the fact that there is no report on the frequency and types of MHC alleles and population genetic analysis in Ross 308 poultry in Iran, the present study aimed to investigate the diversity of MHC haplotypes of Ross 308 broilers by LEI0258 microsatellite.METHODS: A total of 216 blood samples were collected from two productive herds of Ross 308 broilers. After extracting DNA of the blood samples and amplifying LEI0258 microsatellite alleles, genotyping of MHC haplotypes was performed using agarose gel electrophoresis and fragment analysis techniques.RESULTS: A total of seven alleles and 21 genotypes were identified for LEI0258 microsatellite in these two groups. the highest and the lowest frequencies belonged respectively to allele 385 bp (42.86 %) and allele 300 bp (4.33 %). Heterozygous 207/385 was found to be the dominant genotype in both populations. According to the similarity matrix analysis, there was an 84.56 % similarity between the two groups.CONCLUSIONS: The results obtained in this study revealed a high level of heterozygosity (85.71 % and 91.35 %) and deviation from Hardy–Weinberg equilibrium (P<0.0001) in these two Ross populations. Ross 308 broiler chickens had lower allelic diversity and higher genetic similarity compared to the native ones. These findings provided additional information on the use of MHC as a candidate gene marker in genetic improvement and resource conservation in broiler populations.

BACKGROUND: Meat is one of society's most important nutritional needs, the price of which is higher than other food groups. In recent years, the use of meat products has increased due to human lifestyle changes. Fraud in meat products occurs for various reasons, including the economic value of meat. Therefore, it is crucial to use fast and accurate methods of identifying these frauds.OBJECTIVES: The purpose of this study is to determine the unauthorized tissue by a histological method as well as to determine the unauthorized species used in meat products of factories in Hamadan province.METHODS: In the summer of 2021, fifty samples were collected from active production units of the Hamedan province that were available in the Hamadan city market and transferred to the laboratory for histological laboratory and animal species determination by PCR test. For the histology test based on the national standard 6103, the samples were subjected to fixation, passage (dehydration, clearing, impregnation with molten paraffin), blocking, sectioning, and H&amp;E staining. PCR method was used to determine the type of animal species used in the production of the collected samples.RESULTS: The results confirmed the presence of unauthorized tissues, including bone, cartilage (articular and respiratory cartilage), skin, and glandular organ in meat products. Also, PCR test results showed that chicken meat was found in 100% of the samples labeled with beef.CONCLUSIONS: The presence of illegal tissue and the use of chicken meat in products labeled as beef meat is evident in the sausages produced in Hamadan province.

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.

Reviewers 2022