مجله تحقیقات دامپزشکی
سال هفتاد و ششم شماره 3 (پاییز 1400)

Mice are the most common laboratory animals used in research. Parasitic infections in laboratory animals affect both the research results and the health of researchers.

The present study aimed to investigate the infection status of intestinal parasites of mice in three main animal houses in Tehran.

In this study, 75 mice (25 from each animal house) were randomly purchased from an animal breeding house in Tehran and investigated. Mice were euthanized and autopsied. In order to study the gastrointestinal protozoa, wet smears were prepared from different parts of the intestine and feces and stained with Giemsa and Ziehl-Neelsen if necessary. Afterwards, the intestinal contents were examined and helminths were separated. If necessary, specific staining was used to diagnose helminths.

Among the detected parasites, Aspiculuris tetraptera was the most prevalent (% 93.3). The mice were also infected with Syphacia obvelata (% 62.6), Hymenolepis nana (% 61.3), Tritrichomonas muris (% 22.6), Giardia muris (% 21.3), Spironucleus muris (% 18.6), Hymenolepis diminuta (% 17.3), and Cryptosporidium (% 6.6).

Out of 75 adult mice studied, all had at least one parasite. This can affect the research results and jeopardize the health of researchers and related personnel.

Vitamin C and Carum copticum with antioxidant activity may eliminate the negative effects of heat stress on broiler performance and immunity.

This experiment was conducted to investigate the effect of feeding heat-stressed broilers with Carum copticum seed powder (CSP) and vitamin C (VC) on their growth performance, blood metabolites, carcass characteristics, and meat quality.

Herein, we carried out A 2*3 factorial arrangement in a completely randomized design with six treatments, including three levels of CSP (0, 0.75 and 1.5 % of diet), two levels of VC (0 and 250 mg/kg of DM of diet), and four replicates, on 240 one-day-old male Ross 308 broilers. The collected data were analyzed using PROC GLM of SAS. Treatment means were compared employing the Tukey test.

The effect of CSP on their performance was not significant whereas VC treatment improved weight gain significantly (P<0.01). Interaction of CSP and VC on weight gain and feed conversion ratio was significant as broilers fed with 250 mg VC and those fed with 1.5 % CSP had the best WG and FCR (P<0.01). The addition of VC decreased the concentration of alkaline phosphatase in the blood (P<0.05). The heterophil to lymphocyte ratio was reduced through the use of VC and 1.5 % CSP (P<0.05). CSP supplementation at the rate of 1.5 % increased the relative weight of bursa of fabricius (P<0.05). Dripping loss percentage was reduced in birds fed with 1.5 % CP and VC (P<0.01). The effect of CSP and their interaction on water holding capacity was significant and the highest amount belonged to the birds fed with 1.5 % CSP (P<0.01). Additionally, VC increased meat ash percentage compared to the control group (P<0.01).

The results of this study indicated that addition of 250 mg VC and 1.5 % CSP could be conducive to improving growth performance, blood metabolites, and meat quality of broilers under heat stress conditions.

Today, the fight against the bacteria causing foodborne diseases is of particular importance in the packaging of seafood. It is therefore vital to find new compounds with antibacterial properties.

In the present study, antibacterial properties of synthetic nanocomposite zinc chromite-zinc aluminate (ZnCr2O4-ZnAl2O4) on E. coli and Pseudomonas aeruginosa were studied.

After synthesis of nanocomposite, antibacterial activity of nanocomposite zinc chromite-zinc aluminate was evaluated via disk diffusion method, Minimum Inhibition Concentration (MIC), and Minimum Bactericidal Concentration (MBC) using the microdilution method.

The results of this study revealed a higher sensitivity reaction of Pseudomonas aeruginosa (18.6±1.2 mm) compared to E. coli (12.7 ± 1.4 mm). No significant differences were observed between Gentamicin antibiotic and synthetic nanocomposite against Pseudomonas aeruginosa (P<0.05). The minimum MIC and MBC concentrations were seen in Pseudomonas aeruginosa (1.66 mg/ml) and the maximum concentration of MIC belonged to E. coli (5 mg/ml).

In this study, the effects of nanoparticles on these gram-negative bacteria could be attributed to the small diameter of the ions, and hence the greater penetrability of these nanoparticles despite the wall's resistance. Based on the results, zinc chromite-zinc aluminate nanocomposite showed a better performance compared with gram-negative bacteria, specifically Pseudomonas aeruginosa resistant bacteria, and could be used for further studies in fisheries product packaging.

Ensuring health quality of an agricultural or food product is of significance for consumers and could be a decisive factor in terms of attracting and maintaining the market for manufacturers.

The present study aimed to determine the residues of florfenicol antimicrobial agent in the edible tissue (muscle) of rainbow trout reared in Sepidan County (Fars Province, Iran).

50 fresh fish were purchased from 7 farms in Sepidan County. The samples from lateral muscle were taken and kept at -18 °C until the residues drug tests were performed. The florfenicol concentration was measured through the high-performance liquid chromatography (HPLC).

The mean of florfenicol residues in fish muscle reared in Sepidan County was significantly less than the drug products evaluation standard value (P<0.05). However, the concentration of this antibiotic sampled from one of the studied farms went beyond from standard value (1.12 µg.g-1). Of course, this difference was not significant (P>0.05).

It seemed as though the residue levels of florfenicol in the purchased fish reached alarming levels. Meanwhile, it is possible that their average in an area would be within the range of food standards. Thus, it could be suggested that periodic monitoring be carried out continuously by the relevant institutions to ensure that consumer rights are more adequately met.

Fresh sausages are classified as one of the most perishable meat products due to the lack of using chemical preservatives.

The present study aimed to increase the refrigeration time of fresh sausages using Zataria multiflora Boiss. essential oil.

In this study, samples of fresh sausages, containing different concentrations of Zataria multiflora Boiss. essential oil (0, 0.05, 0.1, and 0.2 %), were prepared and stored under the refrigerated condition for 17 days. Subsequently, they were evaluated for microbial, chemical, and sensory properties at six time intervals (days 0, 2, 4, 6, 10, and 17).

Based on the results of the study, by adding Zataria multiflora Boiss. essential oil to fresh sausages, the microbial count in the treatments containing high concentrations of essential oil (0.1 and 0.2 %) was significantly different from that in the control group (P<0.05). The amount of volatile nitrogen bases at the beginning of the study was 14 mg/ 100 g and after six days, in the control group, it reached 32.1 mg/ 100 g. Meanwhile, in the treated samples, it was less than 25 mg/ 100 g up to day 10. Moreover, at the end of the study, the level of TBARS in the control group reached 1.48 mg malondialdehyde /kg while this level was less than 0.78 mg malondialdehyde / kg for the groups treated with Zataria multiflora Boiss. essential oil. The results of this study also showed that the addition of essential oil has a non-significant effect (P>0.05) on sensory properties.

Zataria multiflora Boiss. essential oil was found to have the potential to increase the shelf life of fresh sausages without adverse sensory effects.

Sex determination is an essential issue in certain fish species, like sturgeons. During the rearing management, distinguishing between male and female fish is an important process for producing meat or caviar.

The current study aimed to find the feasibility of electric organ discharge (EOD) frequency ‎generating to introduce a novel method of sex determination in three freshwater species, namely the ‎black ghost knife fish (Aptronotus albifrons), goldfish (Carassius auratus), and the Sterlet ‎sturgeon (Acipenser ruthenus), as non-electric fishes.

In this regard, following sex detection, EOD frequency ‎of fishes were recorded via an oscilloscope. In addition, knife fish was used as a reference sample on which a lot of work has been done to evaluate the accuracy of the method and the use of the oscilloscope. Furthermore, the EOD frequency of male and female ‎Sterlet sturgeons was recorded and reported for the first time in this study.

The frequency ‎magnitude was significantly different in genders of Sterlet (P<0.05) with higher EOD frequency in males ‎than in females. There was no recorded frequency in goldfish ‎male and female. EOD frequencies, which were recorded in male and female of black ghost fish, ‎represented significant differences compared with the other studies (P<0.05).

The results achieved ‎in this study revealed that sex differences are one of the effective parameters in terms of EOD ‎frequency inequality; this non-invasive method can be utilized for sex identification of valuable ‎species, like sturgeon. However, it is required to gather advanced equipment and conduct further ‎research in physiology and biology of reproduction for accurate recording of electrical frequencies ‎and detection of their origins.

Polycystic kidney disease is the most prevalent inherited genetic disease in Persian cats, which is caused by mutations in PKD1 and PKD2 genes. Due to the accumulation of fluids inside the cysts and their pressure on the renal parenchym, the patient is prone to developing symptoms of chronic renal failure.

The present study aimed to compare ultrasonography and molecular tests in diagnosis of autosomal dominant polycystic kidney disease.

This study was performed on 97 Persian cats, including 46 male and 51 female cats, with an average age of 6 years (minimum 2 months and maximum 14 years). All the cats were evaluated for the presence of disease using ultrasound and molecular methods.

Among 97 females, 32 (33 %) were found to be positive for PKD on the basis of presence of anechoic cysts. In molecular tests, all the cases with cysts in the ultrasonography had mutation in PKD1 gene and 13 cases (13 %) without cysts in ultrasonography were diagnosed to be positive through molecular technique. Among 97 studied cats, 45 (46 %) showed mutated genes. The degree of agreement between the two methods of ultrasonography and PCR was determined by calculating Kapa 0.725 (Cl: 0.592-0.895). The sensitivity and specificity of the ultrasonography were calculated to be 77.11 % and 100 %, respectively.

Imaging and molecular methods were utilized to diagnose the disease. The more frequent use of the molecular methods for the diagnosis of the disease compared to the use of ultrasound could be attributed to the higher sensitivity of the molecular technique, the small size of the cysts, the low number of cysts, the low age of the animal, and the presence of cysts in the medula of the kidney. Therefore, the molecular method could be recommended for screening the disease in the early stages. It can also be employed in breeding programs and the removal of cats with this mutated gene.

Serological survey of NDV infection from LBMs would give a good picture of Newcastle disease ecology in a country.

This cross-sectional study was carried out to evaluate the seroprevalence of Newcastle disease in live bird markets, bird parks, and zoos in Iran.

From July to December 2016, blood samples were collected from different bird species in each unit. The serum samples were evaluated via Hemagglutination inhibition test. The seropositive sample was considered a serum with antibody titer 4 or more (1.16) in HI, and units with at least one seropositive bird were considered as the contaminated unit. In this study, the serum samples were taken from various bird species (N=2292) selected from 127 bird markets, bird parks, and zoos distributed in 22 Iranian provinces.

Among the 127 sampled units, 70 (55.12 %) were found to be seropositive. In addition, among the 2292 sampled birds, the number of seropositive birds were found to be 495. Among different bird species, the highest sero-positive prevalence belonged to chickens and turkeys with 38.7 % and 32.89 %, respectively.

The results of this study suggested a high prevalence of Newcastle disease in the live bird markets, bird parks, and consequently, across our country. Given the importance of this infectious disease, it is essential to apply appropriate controlling measures, including continuous surveillances of circulating viruses and vaccination programs with conventional vaccines, such as heat-resistant vaccines. On account of the important role of rural poultry and wild birds in Newcastle disease distribution, controlling the disease in rural poultry and continuous surveillance in both can prevent the spread of NDV, particularly to the commercial poultry.

Leucine is one of the subgroups of amino acids, which play an important role in the anabolism of muscles, adipose tissue, and the liver by stimulating insulin secretion.

Effects of different levels of leucine were investigated on carcass yield, characteristics, and quality, and expression of insulin-like growth factor (IGF-1) and insulin genes in male broilers.

Five levels of L-leucine (100, 110, 120, 130, and 140 % of Ross strain requirements) were tested with 250 male one-day-old chicks in a completely randomized design with five treatments and five replicates (containing 10 chicks each). On day 42 of their age, the blood samples of two birds from each replicate (10 birds per treatment) were taken to determine serum IGF-1 gene expression. Subsequently, these birds were slaughtered for analysis of carcass characteristics and quality, and collecting the samples of liver and breast for expression of IGF-1 and insulin genes.

Body weight increased by consumption of 140 % of leucine as compared to 100 %. Reduction in feed conversion ratio was observed by feeding 140 % of leucine level. The IGF-1 gene expression of breast and liver increased by 110 % of leucine level. Moreover, feeding 110 % of leucine level caused a higher expression of insulin gene in breast and liver. Consumption of 130 % of leucine improved the meat protein, fat, and ash contents. Furthermore, consumption of 110 % of leucine increased the serum IGF-1 concentration.

Consumption of leucine in broiler diets was found to increase the expression of IGF-1 and insulin genes and consequently, improve the performance and carcass quality. It also decreased the abdominal fat in broiler chickens.

The veterinary Rabies vaccine was produced using BHK-21 cells and PV strain. Although various protocols have been suggested for virus purification, they have an adverse effect on the final production and require further optimization.

The present study aimed to optimize the concentration and purification of the virus for rabies vaccine production.

First of all, the Pasteur virus strain (PV) was cultured by using BHK 21 cells with DMEM media contain bovine fetal serum (7 %) for five days. Subsequently, the virus purification was done via tangential flow filtration (TFF) system. The quality of purifying viruses was an assessment with titration and SDS-PAGE. Secondly, the virus inactivation was optimized using Minitab software based on three factors, namely time, temperature, and concentration. Afterwards, the inactivity of the samples was tested on mice. Finally, the virus potency was evaluated by the National Institute of Health (NIH) method.

The viral titration test in TFF samples revealed that viral titer increased in comparison with the control group (P<0.05). The SDS-PAGE analysis of the purified and concentrated samples showed that the purified virus via TFF had a higher purity compared to the not-concentrated samples. Moreover, the NIH test indicated a 10-fold increase in potency result in the TFF group.

The present study implied that the TFF method is highly suitable for condensation and purification of a high volume of viral fluid and could be applied on an industrial scale to increase the potency of the vaccine produced.