BACKGROUND: This study was initiated to improve our understanding  of the health and environmental impact of silver nanoparticles (Ag-np). OBJECTIVES: The purpose of the study is application and direct effects of silver nanoparticles on Zebra fish (Danio rerio). METHODS: After characterizing the AgNPs using TEM, EDX, UV-Vis Spectroscopy, XRF and SEM methods, their effects on some vital tissues have been tested successfully in vitro. In this study, 540 fish (2±0.05 g) were randomly divided into 9 groups in triplicate for acute tests (0,10, 50, 100, 200, 400, 600, 800 and 1000 mg/kgfood). After short term (96h), chronic toxicity tests were evaluated using under lethal concentration (100, 400, 600 and 800 mg/kgfood) fed with experimental diet for 8 weeks. Fish in groups 1 to 4 were fed by food supplemented with 100, 400, 600 and 800 mg/kg food, respectively. Group 5 was fed with basal food without supplementation. After histopathology, heavy metals were measured by spectrum photometry reveal. RESULTS: According to the results of acute tests, the 96h LC50 values in 24, 48, 72 and 96h were 804.601, 486.637, 323.696 and 195.208 mg/kgfood AgNPs for the Zebra fishes respectively. According to the results of chronic toxicity tests, fed via oral administration of AgNPs produced significant histopathological effects. Also, the most important histopathological effects of AgNPs were observed in the liver (vasculature and exposure, degeneration of some hepatocytes), intestine (increase in the submucosa layer, narrowing of the intestinal lumen  and reduced intestinal absorption), gills (clubbing of gill secondary lamaleas, hyperplasia, hyperemia and shortening of the primary lamaleas gills) and kidney (degeneration, high increase in interstitial cells and dilatation of Bowman’s space of glomeruli), respectively. The greatest bioaccumulation of silver occurred in the liver, gills and muscle of fish respectively (p<0.05). CONCLUSIONS: The release of untreated nanoparticle waste to the environment should be restricted for the well-being of human and aquatic species.

BACKGROUND: Lactic acid bacteria are the most common class of bacteria used in aquaculture as probiotic. ObjectiveS: In this study the effects of various levels of Lactobacillus casei on the growth performance and digestive enzymes activity of juvenile Shirbot were evaluated. Methods: Four hundred-eighty juvenile Shirbot weighing 40 g were divided randomly in four treatments (in triplicate). Treatments of A, B and C were fed with 5×106 CFU g-1, 5×107 CFU g-1, 5×108 CFU g-1, respectively for 60 days. Control group was fed with free-probiotic diet. After the period, treatments were fed with free-probiotic diet for 15 days. Growth indices and digestive enzymes were examined on days 0, 30, 60 and 75. Results: In the Treatment B, Specific Growth  Ratio, Daily Weight Growth and Relative Growth Rate, after 30 days from the beginning of experiment improved considerably which, compared to control group had significant difference (p<0.05). Activity of chymotrypsin enzyme in treatment of group B after 30 days and similarly, trypsine in treatment of group C after 30 and 60 days, were increased significantly compared to control group (p<0.05). In the other points of sampling and enzymes, considerable difference was not seen (p>0.05). Conclusions: Results showed that 5×107 CFUg-1 of Lactobacillus casei for 30 days and 5×108 CFUg-1 for 60 days, are the best doses of probiotic.

BACKGROUND: Yeasts are microorganisms that have the ability to absorb aflatoxins. Objectives: The effect of the yeast Saccharomyces cerevisiae (PTCC 5177) on aflatoxin B1 detoxification and absorption of toxin in in vitro (the cow rumen) was investigated. METHODS: For this purpose, the yeast used in various treatments (live-treated, autoclave, heat-treated, treated with acid  100 °C) was prepared and added to the rumen of cattle. Aflatoxin B1 in different doses (0, 5, 10, 20) ppb in the rumen were added and were incubated at 37°C for one and two hours. The amount of toxin residues was measured by ELISA using Europroxima kits. RESULTS: The results showed that microorganisms that have been treated in an autoclave have the highest amount of toxin removal (90.5%) (p<0.05). Also, with increases in the incubation time, the amount of toxin absorbed significantly increased (78%) (p<0.05) and with increasing concentrations of toxin in vitro the yeast’s ability to absorb toxin increases. These results demonstrate  that the major toxin is absorbed by the yeast cell wall and therefore non-living microorganisms shown an ability to absorb higher. This is because the composition of the yeast cell wall mannoprotein that are effective at absorb in toxin. CONCLUSIONS: As a strategy for the animal feed industry the use of glycomannan yeast cell wall can be useful for reducing aflatoxin B1.

BACKGROUND: Caseous lymphadenitis, caused by Corynebacterium pseudotuberculosis, is one of the most important diseases of sheep and goats, causing considerable losses for herd owners. Phospholipase D (PLD) is a potent exotoxin produced by C. pseudotuberculosis and it has been considered as the major virulence factor for this bacterium, possibly contributing to the spread of the bacteria from the initial site of infection to secondary sites within the host. Heat shock proteins (HSPs) are important candidates for the development of vaccines because they are usually able to promote both humoral and cellular immune responses in mammals. OBJECTIVES: The aim of this study was the cloning and expression of the PLD and HSP60 genes of C. pseudotuberculosis, used subsequently to evaluate the protectivity of these recombinant proteins for vaccine development against this bacterium. METHODS: PLD and HSP60 genes were cloned into pMAL-c2X vector and recombinant plasmids construct was transformed to DH5 strain of E. coli. Expression of the proteins was shown by SDS-PAGE and accuracy of the cloned genes was confirmed by nucleotide sequence analysis. RESULTS: The transformed E. coli strain DH5 expressed PLD and HSP60 proteins effectively. The expressed fusion protein was found almost entirely in the soluble form. CONCLUSIONS: In the following studies the immunogenicity and protectivity of these recombinant proteins against C. pseudotuberculosis infections can be assessed.

BACKGROUND: Heat stress reduces the poultry performance through physiologic changes. OBJECTIVES: This experiment was conducted to evaluate the effects of different levels of tryptophane on performance, carcass characteristics and some blood parameters of broiler chickens under heat stress condition. METHODS: Two hundred and fifty one-day-old broiler chicks (Ross 308) were used in a completely randomized design with four treatments and five replicates (pen), 10 birds in each replicate. The chickens of experimental treatments were fed basal diet (control group) and the diets plus the different levels of 100, 120 and 130 and 140% of the Ross strain tryptophane requirements. The experimental diets were used during the finisher period (day 25 to 42 of age) and under heat stress (32±1 ºC as cyclic from 9.00 AM to 5.00 PM). RESULTS: The results showed that the weight gain was  increased linearly by increasing the tryptophane level to 110% of Ross requirements but increasing the tryptophane level to 120, 130 and 140% caused the deteriorated weight gain (p<0.05). The feed conversion ratio was linearly decreased during the finisher and whole the period by supplementation of tryptophane to 110 and 120% but the higher tryptophane levels (130 and 140%) increased the feed conversion ratio during these two periods (p<0.05). Increasing the tryptophane level to 130% of Ross requirements caused a linear increase in the amount of lactate dehydrogenase, alanine amino transferase and alkaline phosphatase (p<0.05). Dietary supplementation of tryptophane had no effect on the blood urea, protein, creatinine, albumin, glucose and cholesterol at day 42 of age but triglyceride (p>0.05). Increasing the tryptophane level to 140% caused the lower blood triglyceride content (p<0.05). CONLUSIONS: Totally, the results of recent experiment show that consumption of 110 and 120% tryptophane of Ross requirements is the best level for performance improvements in broiler chickens under heat stress.

BACKGROUND: The insoluble fiber content of poultry feeds is often considered as an unfavorable factor which reduces the nutritive value of diet. OBJECTIVES: The effects of barley hulls on performance traits of broiler chickens were evaluated. METHODS: The experiment was carried out using 200 Ross 308 broiler chickens in a completely randomized design with 5 treatments and 4 replicates. The experimental diets  consisted of a control hulls-free diet and four diets containing 0.75 or 1.5 percent barley hulls with particle sizes of less than 1 mm or between 1-2 mm. RESULTS: The dietary type did not affect feed intake of the experimental groups. In the whole the experimental period, the weight gain and feed conversion ratio in the broiler chickens feed, the diet that contained 1.5% barley hulls with 1-2 mm particle size improved compared to the control group (p<0.05). In the jejunum, fiber feeding resulted in an increased goblet cell number as compared to the control group (p<0.05). Unexpectedly, barley hulls feeding reduced the villi height compared to the control group (p<0.05). In jejunum the crypt depth in control birds was more than the treatment fed 1.5% barley hulls with less than 1 mm particle size (p<0.05). The ratio of crypt depth to villus height in control group was more than the birds fed the diet that contained 1.5% barley hulls with less than 1 mm particle size (p< 0.05). In ileum the chickens fed the control diet had more lactobacillus and less Escherichia coli than the majority of the treatment fed barley hulls. CONCLUSIONS: Inclusion of 1.5% barley hulls with particle size of 1-2 mm in diet improved performance traits of broiler chickens. On the other hand, using 1.5% barley hulls as a lignocelluloses source increased lactobacillus growth and reduced Escherichia coli population. This alteration in intestinal micro flora suggests a prebiotic effect for barley hulls in the gastrointestinal tract of broiler chickens.

BACKGROUND: Goldfish (Carassius auratus), a carp fish of Cyprinidae family, is one of the most popular aquarium fishes in Iran and also in the world. Ornamental fish trade, especially Goldfish, is aged over a hundred years. If we believe that any aquatic species or country has its own specific and unknown fauna of pathogens, the risks of transmission of these pathogens by importing ornamental fishes (whether at national, provincial or municipal level) will become more obvious. However, few researches have been done about parasitic infections in ornamental fishes. Objectives: Identification and investigation of fish pathogens, especially parasites, prior to transportation to new place is considerably important in the preventing and restricting the transmission of these pathogens.                      Methods: In this study, skin and gills of 100 goldfish were examined by wet mount in order to investigate monogenean parasites. Results: Nine species of parasites from 3 families (Dactylogyridae, Gyrodactylidae and Ancylodiscoididae) were isolated and identified in fishes, including 4 species of Gyrodactylus (Gyrodactylus kobayashii, Gyrodactylus Gurleyi, Gyrodactylus longoacuminatus and Gyrodactylus sp.), 4 species of Dactylogyrus (Dactylogyrus vastator, Dactylogyrus formosus, Dactylogyrus baeri and Dactylogyrus sp.) and 1 species of Ancylodiscoides. Gyrodactylus kobayashii (10%) were the most common parasites found, followed by Dactylogyrus vastator (9%). ConclusionS: Although these fishes are quite resistant against such pathogens, transporting them to a new aquatic ecosystem could transfer these parasites and cause infestation of healthy fishes, which brings about financial losses and casualties.

BACKGROUND: Ostertagia  species are the main domestic ruminants abomasum worms, which cause parasitic gastritis. Parasitic gastritis is associated with disruption of the endocrine structure of abomasum, and influence the function and pH of abomasums. This can lead to weight loss, reduced milk and wool production with potentially mal-digestion of proteins. These cause the economic loss to animal husbandry industry. So, the national research priority in veterinary parasitology is identification of different native species of Ostertagia in Iran. OBJECTIVES: The main purpose of this study is identification and differentiation of Ostertagia species based on the molecular characterization. METHODS: During carcasses inspection at different abattoirs in Rey, Tehran, Mashhad and Bandar Abbas, 180 adult male worms of Ostertagia species from sheep and goat were collected. Morphological analysis was performed based on the morphometric characteristics of spicules. The ITS1, 5.8s and ITS2 ribosomal DNA was ampilified from individual worms by polymerase chain reaction (PCR) and then purified PCR product were sequenced and analyzed by Blast tool. RESULTS: 946 bp PCR products for all sequenced samples were compared with the released sequences of Ostertagia isolates available from GenBank and showed 2-3% differences and 97-98% similarity. CONCLUSIONS: The three species included in the present study are different in terms of molecular property (with 2-3% difference) and it is necessary to determine transmittance pattern and host affinity rules from each one to be used by program managers and evaluators for Prevention and Control programs.

BACKGROUND: Biological control of parasites by using entomopathogen fungi is the one of the recommended ways to control them instead of using the chemical agents. Entomopathogen fungi are not pathogenic for animals and plants, while ticks are one of the most important parasites of animals that can transmit very important microbial pathogens. Ixodes ricinus is a hard tick that infests animals and human. OBJECTIVES: This study demonstrated enzyme assay of entomopathogen fungi hosted on Ixodes ricinus.  METHODS: Enzymatic activities of chitinase, lipase and protease of fungal structures on the killed tick bodies have been assayed by standard sphectrophotometric methods.  RESULTS: Chitinase, lipase and protease activities showed significant differences among different fungal strains (p<0.05). This research, which was done for first time in Iran demonstrated the effect of some enzymes which affect on acaricidal  properties of native strain of entomopathogenic fungi  in Iran. CONCLUSIONS: This study reveals the relationship between enzyme level of fungal strains and  the possibility of selecting more effective strains of entomopathogenic fungi

BACGROUNDS: Heat stress causes the lower performance in broiler chickens. OBJECTIVE: This research was conducted to investigate the effect of betaine supplementation in broiler chickens under heat stress condition. METHODS: Two hundred one-day-old male broiler chicks (Ross 308) were used in a completely randomized design with 4 treatments and 5 replicates per treatment and 10 birds per each replicate. The experimental treatments were the heat stressed birds fed the different levels of 0.0 (without any dietary supplement), 0.05, 0.1 and 0.2% betaine. The experimental diets were added to the diets during the finisher period (day 25 to 42 of age) and under heat stress condition (32±1º C from 9.00 AM to 5.00 PM). RESULTS: The results showed that feed consumption was not affected by betaine supplementation. Consumption of 0.2% betaine resulted in a higher weight gain during the whole period as compared to 0.05 betaine and control diet (P<0.05). The consumption of all betaine levels caused the decreased feed conversion ratio during the finisher period (P<0.05) and 0.2% betaine resulted in lowest feed conversion ratio between the experimental treatments. Dietary betaine supplementation had no effect on internal organ weights of heart, liver, abdominal fat, spleen and bursa at day 42 of age (P>0.05). Furthermore, consumption of different betaine levels had no effects on blood indices, the amounts of blood enzymes and antioxidant status at day 42 of age (P>0.05). CONCLUSIONS: Totally, the consumption of 0.2% betaine improves the performance without any effects on blood indices and internal organs under heat stress condition.