مجله تحقیقات دامپزشکی
سال هفتاد و ششم شماره 4 (زمستان 1400)

Neosporosis is a disease caused by the protozoan Neospora caninum, which is characterized by abortion in cattle and neuromuscular paralysis of various organs, particularly the hind limbs of dogs. The diagnosis of neosporosis is often made by serological molecular tests.

This study was conducted to investigate the presence of N. caninum oocysts in the feces of dogs.

A total of 100 fecal samples were collected from indoor and outdoor dogs during 2018-2019 around Tabriz. Information about age, location, and history of antiparasitic treatment of the dogs were recorded in a questionnaire. Primarily, fecal samples were examined microscopically for Neospora ocysts. After breaking the collected oocysts through freeze-thaw and sonication, DNA contents of the oocysts were extracted and analyzed via PCR.

In a light microscopic study, oocysts were observed in 45 (45 %) of the fecal samples. In the PCR study, 21 of the 45 cases tested positive for Neospora infection (21 %). All the positive cases of infection were observed in molecular examination in dogs older than one year. The positive cases were observed in 2 % of the domestic dogs, 8 % of the stray dogs, 6 % of the kennel dogs, and 5 % of the rural dogs. Furthermore, 19 % of the infected dogs had no history of antiparasitic treatment; only 2% had a history of antiparasitic treatment. The results of statistical analysis showed that the rate of infection in dogs around Tabriz with Neospora caninum was significantly (P<0.05) related to the animal's living environment and history of antiparasitic treatment. However, this rate was found to have no significant relationships with the age of the animals.

Due to the high rate of infection with Neospora caninum in dogs in Tabriz, it is necessary to apply preventive methods in traditional and industrial farms around this city and use rapid diagnosis methods in them.

As the population grows, there is further need to food, and fish is not an exception. Several fish species are potential sources of common parasites between humans and fish. One of the important diseases common between human and fish is Anisakiasis. The parasitic agent of this disease is the larval stage of the Anisakid family nematodes, including Pseudoterranova and Anisakis.

In this study, Epinephelus fish, one of the edible and commercial valuable fishes of the Oman Sea, was examined for the presence of nematodes of the Anizakidae family.

Fifteen out of the 26 specimens were infected with Nematodes. Nematodes were isolated from fish abdominal area. For morphological study, each nematode sample was first clarified with lactophenol. Subsequently, it was examined using an optical microscope. After morphological examination of these nematodes, DNA extraction was performed. Using primers related to a part of cytochrome oxidase subunit 1 (Cox1), PCR products were 710 bp for PCR reaction. Finally, the amplified fragment was sequenced.

The larvae were about 1 to 3 cm long, white, and often twisted. At the anterior end of the parasite, a button was seen, and in some larvae, a terminal spine was observed. In certain larvae, a small abdomen at the end of the esophagus can be seen. Out of the obtained 26 nematode specimens, eight Anisakis specimens were identified following morphological analysis. These specimens had terminal spines and three anterior lips. After sequencing, Pseudoterranova nematode was identified to belong to aniakidae family. Separate clad tree showed paraphylitic for isolated Pseudoterranova.

Morphological examination categorized isolated larvae as the Anizakidae family. Other molecular results of this nematode showed Pseudoterranova krabbei. The results of sequencing this parasite were recorded in the gene bank under the Accession number: MK317965. This nematode was initially isolated from the Oman Sea Epinephelus fish.

Omega-3 fatty acids can be conducive toreducing the harmful effects of physiological stress through reducing the stimulatory activity of glutamatergic neurons.

The aim of this study was to investigate the effects of omega-3 fatty acids on performance, blood parameters, and the profile of fatty acids in the egg yolks of laying hen under stress.

This study was performed using 96 LSL-Lite laying hens in a 2 × 3 factorial experiment with 2 factors, namely stress (no dexamethasone and 1.5 mg/kg of diet dexamethasone) and omega-3 fatty acids (the levels of 0, 0.24 and 0.48 % of diet), in a completely randomized design for 70 days from 35 to 44 weeks of age.

Physiological stress reduced the feed intake, the percentage of egg production, and egg mass in laying hens (P<0.05). Omega-3 fatty acid supplements had no effects on these traits. The groups receiving 0.48 % of omega-3 fatty acids had the lowest heterophil:lymphocytes (P<0.05), and there was no difference between stressed and non-stressed groups. The ratio of omega-6 to omega-3 fatty acids was higher in birds previously affected by stress (P<0.05). Feeding with omega-3 fatty acids in birds increased omega-3 fatty acids in egg yolk and reduced the ratio of omega-6 fatty acids to omega-3 in laying hens (P<0.05).

Based on the results of this experiment, physiological stress had a negative effect on performance traits, and the use of omega-3 fatty acids in laying hens under stress had no effect on performance traits. Physiological stress altered the profile of fatty acids and increased the proportion of omega-6 to omega-3 fatty acids in egg yolk. The use of omega-3 fatty acids reduced the negative effects of stress and improved the profile of fatty acids in egg yolk.

Optimal levels of minerals in the diet are crucial for improving performance and immune response against the environmental stresses.

This study was conducted to evaluate the effects of water supplementation of chelated trace mineral (CTM) on growth performance, hematology, blood biochemistry, antioxidant status, and antibody response in broilers reared under heat stress condition.

A total of 240 male Ross 308 broiler chickens were randomly allocated into one of the following five treatments (each consisting of four replicates): (1) positive control (PC; thermoneutral condition), (2) negative control (NC; heat stress condition), (3) low-CTM (NC + low CTM level in tap water), (4) medium-CTM (NC + medium CTM level in tap water),  and (4) high-CTM (NC + high CTM level in tap water). The CTM levels in the tap water for the low-CTM treatment were 0.1, 0.15, 0.3, 0.4, and 0.45 mg/bird/day on days 1-10, 11-20, 21-30, 31-40, and 41-50, respectively. The respective values were 1.0, 1.5, 3.0, 4.0, and 4.5 for the medium-CTM, and 10, 15, 30, 40, and 45 mg/bird/day for the high-CTM water.

The average weight gain during the whole experimental period in the medium-CTM treatment was higher compared to that in the negative control treatment, but lower than that in the positive control treatment (P<0.05). The heterophil/lymphocyte ratio and total antibody titers against Newcastle disease in the medium-CTM and high-CTM groups were similar to those of the broilers in the PC group, yet better (P<0.05) those of the NC group. The serum superoxide dismutase activity was also higher (P<0.05) in the high-CTM group compared to that of the NC group.

The results suggested that the water supplementation of CTM at a moderate level (1.0, 1.5, 3.0, 4.0, and 4.5 mg/bird/day during different rearing periods) could be a strategy to ameliorate the detrimental effects of heat stress in broilers.

There are different kinds of phytase from different sources used in poultry nutrition.

The present study aimed to evaluate the effects of addition of 2 sources of 6- phytase to the diet of male broilers in terms of growth performance, Tibia biometric, breacking straight, mineralization, blood biochemical parameters, and carcase yield.

Herein, we recruited 216 1-d-old male Ross broilers and divided them to three experimental groups and six replications for 42 D. The treatment (T) diets included: T1 (without phytase (control)), T2 (supplemented with 500 FTU/kg diet of Aspergillus niger phytase (fungi phytase)), T3 (supplemented with 500 FTU/kg diet of phytase produced by a genetically modified strain of Aspergillus oryzae by doner Citrobacter braakii gene (genetically modified phytase)).

Serum P in the birds supplemented by genetically modified phytase was higher compared with that in the control birds (P<0.05). Additionally, Tibia P in this group was higher than that of birds supplemented by fungi phytase (P<0.05). However, Tibia breaking straight in birds supplemented by genetically modified phytase did not differ significantly with those fed with a diet with fungi phytase. Meanwhile, Tibia breaking straight in birds supplemented by genetically modified phytase was higher than control (P<0.05). Growth performance, Tibia length, diameter, ash, Ca, dry weight, average serum HDL, Triglyserid, Cholesterol, Ca, Alkalin phosphatase, Glucose, Total Protein, and Carcase yeild were not significantly different among any of the treatments.

Supplementation of male broilers diet with genetically modified phytase (500 FTU/kg), without any differences in terms of performance, could increase P of serum, P of Tibia and breacking straight of Tibia compared to supplementation diet with Aspergillus niger phytase.

On account of the importance of iodine in the synthesis of thyroid hormones, different levels of dietary iodine can affect the occurrence of ascites syndrome in broilers.

The current research aimed to investigate the effects of different sources and levels of iodine on performance, carcass traits, ascites mortality, thyroid hormones, and serum biochemical parameters of broiler chickens under cold stress condition.

This experiment was performed using 375 one-day-old male broiler chickens in a completely randomized design with five treatments, five replications, and 15 birds per replication. To induce ascites, the room temperature was reduced to 15 °C from 14 days and this temperature was maintained until the end of the period. The experimental treatments included: control treatment (basal diet with iodine at the recommended level, 1.25 ppm), basal diet + potassium iodide (KI) with iodine levels (6.25 and 3.75 ppm), and basal diet + calcium iodate [Ca(IO3)2. H2O] with iodine levels (6.25 and 3.75 ppm).

The effect of the treatments on the performance indices was not significant throughout the experiment. The lowest percentage of ascites mortality, heart weight, and triiodothyronine (T3) were observed in the treatment (6.25 ppm), which was significantly different from the control treatment (P<0.05). The lowest ratio of right ventricle to total ventricles (RV/TV) was related to potassium iodide treatment (6.25 ppm), which indicated tendency (P<0.10). Chickens receiving higher levels of iodine (6.25 ppm) had higher thyroxine than those receiving lower levels (3.75 ppm) (P<0.05) and showed a lower ratio of triiodothyronine to thyroxine compared to those (P<0.05).

The results of this experiment implied that the use of higher levels of dietary iodine (6.25 ppm), especially as potassium iodide, reduces broiler’s ascites mortality under cold stress conditions.

Ammonia accumulation in warm-water fish pond can lead to mortality or reduction in growth and body immune indices.

The present study aimed to investigate the effects of chronic sub-lethal unionized ammonia (NH3) on growth indices and gill and kidney histopathology l, after a 30 – day trial in common carp (Cyprinus carpio).

Herein, 180 fish with an average weight of 4.5±0.5 g were divided into six tanks. Two groups, including one control group and one treatment group (with three replicates for each one), were considered. The treatment fish were exposed to 0.1 mg/l on un-ionized ammonia (NH3) for 30 consecutive days. Following one -month, ammonia exposure growth indices and histological analysis of gill and kidney were investigated.

The results showed that exposure to 0.1 mg/l of NH3 led to a significant reduction in growth indices. Additionally, edema and epithelial lifting with hyperplasia in the second lamella were detected in the gill of the treatment group. The kidney was characterized by focal renal tubules degeneration and necrosis, congestion, and increase in the melano-macrophage centers.

Although chronic exposure to 0.1 mg/l of unionized ammonia was not found to cause mortality in common carp, it could have some side effects, such as a decline in growth indices and histopathological effects in kidney and gill tissues. Thus, for higher production, sublethal levels of ammonia should also be taken into account in common carp ponds.

Open wounds affecting the distal part of limbs are commonly seen in horses. Due to certain factors, such as limited connective tissue available, potentiated growth of excessive granulation tissue, risk of contamination, and poor response to common treatments, healing of these wounds becomes a major problem for veterinarians on a number of occasions. Application of Mesenchymal Stem Cells (MSC) for enhancing wound healing has received a great deal of scientific attention. Among the MSCs, those derived from adipose tissue are frequently used owing to their availability, large number of cells after the primary harvest, and the capacity to differentiate to different cell lines.

The current study aimed to evaluate type 1 and 3 collagen genes expression in horse distal limb wounds treated via adipose-derived Mesenchymal Stem Cells and its comparison with bone marrow-derived stem cells.

After treatment of the experimental open wounds created in the distal limbs of four horses via autologous MSCs, real-time PCR was used for evaluating and comparing the expression of type I and III collagen genes in the healing wounds.

Significant differences in the expression of type I and III collagen genes were observed between the treatment groups. Despite the fact that the greatest collagen genes expression belonged to bone marrow-derived MSCs, no significant differences were seen with adipose-derived MSCs.

Owing to the advantages and an acceptable performance, adipose-derived MSCs could be considered as a novel approach to enhancing limb wound healing in horses.

During the modification of several races, which has been done on chickens, there have been several changes in the function of neural pathways and receptor density involved in the control of food intake and appetite. Melanocortin system and its receptors are involved in the central regulation of nutritional behaviour and energy balance. Therefore, this study was designed to investigate the role of this system in the central control of food and water intake in birds.

The present study aimed to evaluate the role of MCR3 and MCR4 receptors in controlling the food and water intake in birds.

This work was performed on 48 Ross 308 broiler chicks through two experiments (each experiment in four groups). Primarily, stereotaxic surgical guide cannula was implanted in the chickens. Subsequently, in the first experiment, the chickens were divided into the four following groups: the control solution, 0.2, 2, and 10 nmol/5µl of SHU9119 (Non-selective antagonist of MCR3 and MCR4 receptors) In the second experiment, the chickens were also divided in four groups: the received control solution, 0.2, 2, and 10 nmol/5µl of MCL0020 (Selective MCR4 receptor antagonist) via intracerebroventricular (ICV) injection. Afterwards, cumulative food and water intake were measured at 30, 60, 90, 120, 150, and 180 minutes after the injection.

The results of this study showed that ICV injection of SHU9119 and MCL0020 increased cumulative food intake (P>0.05), but did not affect cumulative water intake (P<0.05).

According to the findings herein, central melanocortin system is one of the systems involved in central control of food intake in birds.

Tilapia, Oreochromis niloticus, is an omnivorous and important breeding species in the world. Over the recent years, tilapia breeding has begun in Iran. In aquaculture, it is very important to regulate a balanced diet in terms of nutrients needed for growth, which would be also economically appropriate.

The main objective of this study was to investigate the effect of substituting chicken waste powder in the diet of fish at levels of 0, 25, 50, 75, and 100 % on the tissue structure of different parts of the intestine of Nile tilapia.

75 fish (three frequency per treatment) were fed with chicken waste powder instead of fish meal in their diet for eight weeks at 0, 25, 50, 75, and 100 % levels. At the end of the treatment, separate samples were taken from the initial, middle, and end parts of the intestine. After passing the usual histological steps, the slides were assessed by hematoxylin-eosin staining and TUNEL immunohistochemistry technique.

In histometric studies, the highest villi height, thickness, muscle layer, and number of goblet cells were reported in the control group and the lowest in the 100 % group. In immunohistochemical studies, the number of apoptotic cells in groups 75 and 100 % was higher than that in the other groups.

According to the results of the present study, it could be suggested that the replacement of chicken waste powder instead of a fish meal up to 50 % for indigo tilapia is tolerable. However, higher levels of chicken waste powder will reduce absorption, and acceptance of food and have adverse effects on growth.