مجله تحقیقات دامپزشکی
سال هفتاد و هفتم شماره 4 (زمستان 1401)

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.

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.

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&E staining. PCR method was used to determine the type of animal species used in the production of the collected samples.

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.

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.

There is growing evidence that resistance to antibiotics is increasing, and because of their wide range of negative impacts on the environment and humans, also accumulative effects in fish meat and hazards for humans, there have been numerous studies conducted using medicinal plants as a healthier alternative to antibiotics.

This study examined the antibacterial effect of two native medicinal herbs (oregano and echinacea mixed essential oil) on Lactococcus garvieae compared with some commercial antibiotics used in fish farms.

The antibacterial activities against a fish bacterial pathogen (Lactococcus garvieae) were tested using the disk diffusion method, followed by the determination of minimum inhibitory (MIC) and bactericidal (MBC) concentrations via sequential dilution of essential oil by Broth Micro Dilution method.

The results showed antimicrobial activities of mentioned mixed essential oil with MIC ≥ 6.25 μL/mL and MBC ≥ 12.5 μL/mL. Also, the measurements of the diameter of inhibitory zones are consistent with the results of MIC and MBC, indicating the positive effect of this plant mix oil Lactococcus garvieae. However, the Lactococcus garvieae was more sensitive to Enrofloxacin (NFX 5), and Sulfamethoxazole & Trimethoprim (SXT) (P<0.05), but the combination of Oregano and Echinacea essential oils performed better than Florfenicol (FF) despite the weaker effects against mentioned two antibiotics.

The results approved the antibacterial activity of the mixed essential oil of oregano and Echinacea against Lactococcus garvieae on the laboratory scale. Using these compounds as a possible substitute for antibiotic compounds requires more clinical studies.

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.

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.

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.

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.

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.

Storing semen at a temperature of 4 degrees Celsius reduces its motility and quality.

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.

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.

Based on the results, different calcium compounds in most concentrations could significantly affect the parameters of survival, mobility, and progressive mobility (P<0.05).

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.

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.

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.

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.

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).

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.

Bovine Herpes Virus-1 (BHV-1) belongs to the  Alpha herpesviral family. The virus is the cause of Infectious Bovine Rhinotracheitis (IBR) and Bovine Abortion. In the initial infection, the virus proliferates excessively. Moreover, shedding the virus leads to conditions in the latent phase of the disease. Infectious Bovine Vulvovaginit (IPV ) is the genital form of the disease that represents a genital infection and transmits via pustules and mucopurulent secretions. Exposure to the virus in genital mucosa leads to IPV infection through mating or artificial insemination and the diseases that can be transmitted to healthy livestock by frozen sperm during artificial insemination.

Viral contamination of the semen is one of the routes to spread the disease among dairy cattle. Therefore, we investigated the presence of the virus in domestic and frozen imported semen consumed in industrial dairy cattle farms.

In the present study, 140 frozen straws were collected. After melting each straw, 200 µl of obtained semen was used for DNA extraction, which was done directly on the semen samples and via a Genome Extraction Kit. Subsequently, to ensure the accuracy of the extraction, the PCR technique was done using PRM-1 gene primer. Tracking the viral genome was done using the PCR technique and known primers.

In total, one out of 140 samples was found to be virally contaminated, and IBR contamination was confirmed by repeating all the steps and determining the gene sequence.

It is necessary to further investigate the possibility that contamination can be transmitted via frozen semen, given that even one out of 140 samples is contaminated, and the importance of the disease.

Stenotic nares and malocclusion are common congenital disorders in the brachycephalic breeds of cats which cause respiratory and oral problems in these breeds, respectively.

In this study, the prevalence of two congenital disorders, stenotic nares, and malocclusion, the correlation among them in brachycephalic breeds of cats referred to several private veterinary clinics in Tehran were evaluated.

90 brachycephalic cats were evaluated for stenotic nares, and malocclusion and indices was checked, then determined the prevalence percentage and correlation with the statistical data between stenotic nares and malocclusion in brachycephalic breeds of cats were referred to several private veterinary clinics in Tehran.

Malocclusion was diagnosed in 35 cats (38.9 %), stenotic nares were detected in 31 cats (34.4 %), and two diseases were diagnosed in 17 cats (18.9 %) concurrently in 90 brachycephalic cats. According to a statistical test, the probabilities of identifying the second disease are 2.7 times higher if one of the two disorders is identified.

The prevalence of stenotic nares and malocclusion in brachycephalic cats is very high and there is a significant correlation between two disorders so clinicians should have great attention in their clinical examination of these two disorders in these breeds.