مجله تحقیقات دامپزشکی
سال هفتاد و هفتم شماره 1 (بهار 1401)

RPMI 1640 is one of the most widely used culture media for the growth of microorganisms such as Leishmania, which is typically enriched with 10-30 % of fetal bovine serum (FBS) or calf serum (FCS) due to having growth factors such as micronutrients, trace elements, and hormones.

As a result of limitations such as the high cost of commercial sera and the recent propagation of ostrich and camel breeding in our country as well as the possibility of obtaining their sera comprising growth factors similar to FBS or FCS, we decided to compare different percentages of these sera with FBS regarding the growth of two Leishmania species.

1×106/mL of Leishmania major and Leishmania tropica were cultured in RPMI 1640 in the presence of different percentages of 2.5-30 % related to all three sera; they were then counted, compared, and analyzed on different days up to the fourteenth day.

The highest proliferation of both Leishmania species was observed in the presence of all percentages of FBS up to day 7. In media enriched with less than 5 % of both ostrich and camel sera, the growth of the two species of Leishmania was favorable; however,with the increase in the amount of these sera, the proliferation of both species decreased. While only 10 % of sera was compared, the highest growth of L. major and L. tropica was observed in the presence of FBS followed by camel serum.

For 5 % and less concentrations, each ostrich and camel sera and for 10 %, only camel serum are recommended as substitutes for FBS in RPMI 1640 concerning the cultivation of L. major and L. tropicafor a week of incubation;if more than 15 percent is required, FBS is still the best option.

Today, due to the high cost of animal proteins on aquatic diets, a great deal of attention has been paid to further use of plant proteins.

The present study aimed to replace fish meal with corn protein concentrate (CPC) (Empyreal® 75) and investigate its effect on growth, survival, and body composition of Siberian sturgeon (Acipenser baerii).

Corn protein concentrate was replaced with fish meal at four levels of 0, 15, 30, and 45 % in three replicates in a completely randomized design. A total of 120 Siberian sturgeons weighing 8.27±0.39 g were distributed into twelve 80-L round plastic tanks with a density of 10 fish per tank. After a week of acclimatization period, fingerlings were fed with four diets with the same protein and energy levels (isonitrogenic and isocaloric) for 60 days. At the end of the experiment, growth parameters and carcass composition were measured.

The results revealed that the total length, final weight, body weight increase. Specific growth rate, average daily growth, protein efficiency ratio, and condition factor were significantly higher in fish fed with corn protein concentrate at the level of 15 % compared to the other treatments (P<0.05). The food conversion ratio had the lowest value in this treatment, which showed a significant difference with the other treatments (P<0.05). A significant difference in carcass protein was observed in fish fed corn protein concentrate 15 % and 30 % in comparison with fish fed with 45 % corn protein concentrate. The survival rate was 100 % in all the treatments.

Based on the obtained findings, it could be stated that corn protein concentrate at the level of 15 % can be a good substitute for fish meal in Siberian sturgeon diet.

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.

This study aimed to investigate the infection rates of this bacterium via PCR.

295 tracheal swabs were collected from 10-layer flocks. Subsequently, the suspected colonies were isolated and identified with morphological features, differential cultivation, and PCR.

43.72 % of the samples were positive.

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.

The widespread use of electromagnetic waves in communication has led to the consideration of their biological effects. According to valid scientific findings, these waves can entail changes in the cell function, there by causing or accelerating some diseases.

Since the amount of liver enzymes in the blood can be a sign of liver damage, this study was performed to evaluate these enzymes.

This experiment was done on 120 six-month-old pigeons. After adaptation to laboratory settings, they were divided into six random groups of distance from BTS and daily exposure time. G1: 50 cm/30 minutes, G2:100 cm/30 minutes, G3: 150 cm/30 minutes, G4: 50 cm/60 minutes, G5:100 cm/60 minutes, and G6:150 cm/60 minutes.Each group was exposed to waves for one month daily and blood tests were measured to determine the amount of liver enzymes before and one month after exposure; the results were processed by SPSS software.

The findings of this study revealed a statistically significant relationship between BTS waves and liver damage after the increase in the level of liver enzymes in all six groups. Therefore, it is safe to assume that electromagnetic waves, depending on the frequency, energy, duration and distance, can have destructive effects on body tissues, including the liver. The mean changes of ALP and ALT were the highest and the lowest, respectively. Also, the most changes in liver enzymes occurred in the first and fourth groups, which had the shortest distance to the wave source.

Increasing the exposure time and reducing the distance to the wave source changed the amount of liver enzymes. This study showed that "distance to the source of wave propagation" was more important than "exposure time".

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.

A feeding trial was conducted to evaluate the effects of NT supplementation on growth performance and stress resistance of fry kutum (Rutilus kutum).

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.

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).

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.

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.

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.

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.

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.

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.

Clinical and pathological findings were described in stillborn kids affected with congenital goiter in a goat flock of Beetle breed in Garmsar Iran.The observations involved seven stillborn kids with goiter, including one case with triplet fetuses and two cases with twine fetuses. The thyroid glands were clearly visible, enlarged, and palpable in all the dead kids. The fetuses had a large swelling in the cranio-ventral neck region. Upon cutting skin in each fetus, the swelling revealed the extremely enlarged thyroid gland with two almost symmetrical lobes with both lobes approximately 15 × 8 × 5 cm in size.Histopathological hyperplastic goiter was observed in four kids and colloid goiter was diagnosed in three.Twins or triplets were observed to be predisposed to congenital goitre. All the stillborn kids were twins or triplets. On the other hand, single-born kids survived and showed a normal growth rate.