شناسه هاي افزوده :
شريفروحاني، مصطفي ، همكار طرح , فخارزاده، محمداسماعيل ،همكارطرح , نجارلشگري، سلطنت ،همكارطرح , يوسفي، رحمت ،همكارطرح , قنبري، فرهاد ،همكارطرح , رضواني، ابوالفتح ،همكارطرح , پورمولائي، بهنام ،همكارطرح
چكيده انگليسي :
The aim of this study was to investigate the antimicrobial effects of powder and nano-powder of Origanum vulgare extract (new formulation) on Streptococcus iniae by bacterial culture test and field methods (prevention and treatment of experimental Streptococcosis) in rainbow trout (Oncorhynchus mykiss) and its comparison with florfenicol and nano-florfenicol (new formulation).
Also, the effects of powder and nano powder of Origanum vulgare extract on some blood parameters including hematocrit, total and differential count of white blood cells, some biochemical parameters of blood including glucose, cortisol and lysozyme enzyme activity as well as tissue damages including tissuses of liver, spleen and kidneys in two phases of prevention and treatment and their comparison with the effects of florfenicol and nano-florfenicol. In laboratory method, standard methods of dilution of the liquid in a tube (broth microdilution) were used for determining the minimum growth inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) as well as disc diffusion method was used for measuring zones of inhibition. In the field methods, the effects of powder and nano-powder of Origanum vulgare extract in two phases of prevention and treatment were compared with the effects of florfenicol and nano-florfenicol. 900 rainbow trout (450 at the prevention phase and 450 at the treatment phase) with an average weight of 15±1 g was used in 5 experimental groups and each group with 3 replications including: 1) non-drug-based diet group (negative control); 2) basic diet group containing powder of Origanum vulgare extract 1%; 3) basic diet group containing nano- powder of Origanum vulgare extract 1%; 4) base diet containing 10 mg of florfenicol per kg of weight (positive control); 5) The base diet group containing 10 mg of nano-florfenicol powder for each kilogram of weight. In the prevention phase, at the end of the second week after medicine therapy with their special medication, all fries were infected through intraperitoneal injection of 100 μl suspension of Streptococcus iniae with a MacFarland standards
(3×1010cfu). But, in the treatment phase, the biginning, all of fries were infected through intraperitoneal injection of 100 μl suspension of Streptococcus iniae with a MacFarland standards (3×108 cfu); then, were treated with their special medication for 2 weeks. Losses were collected and recorded daily and analyzed at the end of tests. In each phase, blood and tissues samples were taken at the end of the second week after medication therapy and at the end of the second week after discontinue medication therapy. The results showed that the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were 1000µg/ml with powder of Origanum vulgare extract, 250µg/ml (MIC) and 500µg/ml (MBC), with nano-powder of Origanum vulgare extract, 7.8μg/ml (MIC) and 3.9μg/ml (MBC) with florfenicol powder and 3.9μg/ml (MIC) and 1.9μg/ml (MBC) with nano-florfenicol powder respectively.
The results of the diameter of inhibition zones with powder of Origanum vulgare extract were 21.7±0.8 mm, with nano powder of Origanum vulgare extract, 26.66±0.3 mm, with florofenicol powder 31.63±0.4 mm and with nano-florfenicol powder, 32.80±1/1 mm. There was a significant difference between treatments (p <0.05). The results of this study indicate that Streptococcus iniae are sensitive to Origanum vulgare extract, but its susceptibility was higher to nano powder of Origanum vulgare extract. In comparison of between different groups, the sensitivity of Streptococcus iniae to the nano-florfenicol powder was higher other than medicines. These results show that the nano powder form of the medicines have a better anti-Streptococcus iniae effect than its usual form. The results of serological studies of the prevention phase at the end of the second week after medicine therapy in non-infected fishes of Streptococcus iniae showed that the powder and nano powder of Origanum vulgare extract had no effect on blood cortisol concentration, but at the end of the second week after discontinuation of the medicine, cortisol concentrations in infected fishes of Streptococcus iniae was significantly increased in all treatments. However, increasing blood cortisol concentrations in powder and nano powder Origanum vulgare extract treatments were lower than other medicinal and control treatments. There was no significant difference in blood cortisol concentration between the recent two treatments (p <0.05). These
results indicate that inoculate of Streptococcus iniae bacteria increases the concentration of cortisol during this period of the prevention phase. Also, the results of serological studies in the treatment phase showed that none of the medicines had no effect on the cortisol concentration of infected fish at the end of the second week after medicinal therapy. But, the blood cortisol concentration at the end of the second week after the discontinuation of medicinal treatment in powder and nano powder of Origanum vulgare extract was reduced compared with other medicinal and control treatments (p <0.05). These results indicate that the powder and nano powder of Origanum vulgare extract have been effective in controlling stress and decreasing blood cortisol secretion. The study of blood glucose concentration was other results of serum tests that it showed blood glucose concentration in the end of the second week after medicinal therapy in infected and uninfected fishes to Streptococcus iniae bacteria in medicinal treatments, except Origanum vulgare extract treatment increased in comparison with control treatment (p <0.05). This suggests that the use of these substances, except powder of Origanum vulgare extract has increased blood glucose concentrations. Also, blood glucose concentration increased at the end of thesecond week after discontinuation of medicinal therapy in infected fishes of Streptococcus iniae bacteria in medicinal treatments compared to control treatment, but this increase was less than the previous period. This suggests that these substances and or the length of time can help control stress and reduce glucose secretion. Also, at the end of the second week after medicinal therapy, the blood glucose concentrations increased in infected fishes of Streptococcus iniae in comparison with the control treatment. This suggests that none of the substances have no been effect on blood glucose concentrations of infected fish following infection with Streptococcus iniae. Also, the concentration of blood glucose in infected fishes of Streptococcus iniae was significantly higher in medicinal treatments than the control treatment at the end of the second week after medications discontinuation, but the blood glucose concentration decreased in all treatments compared to the previous period. These results indicate that it can be probably due to the effect of the use of medications or the reduction of bacterial load over time. Other results of this research in the prevention phase showed that lysozyme enzyme activity in non-infected fishes of Streptococcus iniae increased at the end of the second week after medication therapy in comparison with the control treatment (p <0.05). However, the activity of lysozyme enzyme was lower in powder and nano powder of Origanum vulgare extract in compared to other treatments at the end of the second week after medication discontinuation. The results showed that blood lysozyme enzyme activity was higher in medications than control treatments in infected fish to Streptococcus iniae bacteria (p
<0.05). However, at the end of the second week after the medications discontinuation, the lysosyme enzyme activity was less than the previous period. These results indicate that the level of lysozyme enzyme activity has been reduced due to the progression of treatment and the reduction of bacterial load. The results of hematological studies in the prevention and therapeutic phases showed that the Origanum vulgare extract did not affect on the hematocrit percentage and the total count of white blood cells (p <0.05); but the nano powder of Origanum vulgare extract increased the blood hematocrit and total cell count white levels at the prevention phase (p <0.05). In the prevention phase, none of used medications have no any effect on the differential count of the white blood cells. However, the percentage of monocytes in nano-powder Origanum vulgare extract, powder and nano powder of florfenicol were increased in comparison to powder of Origanum vulgare extract and control treatments (p <0.05). Other results of this study, reducing the spleen bacterial load in the medications treatments in comparison to the control treatment in both prevention and therapeutic phases. The results of tissue pathology in two phases of prevention and therapeutic showed that Origanum vulgare extract had no significant negative effect on the tissues in question. This suggests that the addition of 1% of Origanum vulgare extract to fish food has not produced toxicity for fish. Also, the percentage of casualties in both prevention and therapeutic phases was lower in medications treatments than control treatment. In conclusion, it can be concluded that Origanum vulgare extract can be considered as a complementary antibacterial agent in aquaculture industry. Therefore, since chemical antibiotics increase the resistance of pathogenic bacteria, environmental pollution and adverse effects on fish and humans (fish consumers), the consumption of powder Origanum vulgare extract in the aquaculture industry will be very useful and valuable. Because it does not have the side effects of chemical antibiotics. Secondly, it reduces the consumption of chemical antibiotics and subsequently reduces drug resistance in aquatic animals.
كليدواژه :
ﻋﺼﺎره آﺑﯽ- اﻟﮑﻠﯽ , ﻣﺮزﻧﮕﻮش , ﺿﺪ ﺑﺎﮐﺘﺮي , ﺿﺪ ﺑﺎﮐﺘﺮي , اﺳﺘﺮﭘﺘﻮﮐﻮﮐﻮس اﯾﻨﯿﺎﯾﯽ , ﻓﻠﻮرﻓﻨﯿﮑﻞ
