تأثير أدوية مضادات الالتهاب غير الأرسترادية على معدل النمو البقاء في أسماك البلطي (المشط) The Effect Of Anti prostaglandin COX2 on NileTilapia Fish Growth Rate and Mortality Rate

Date
2017-11-11
Authors
إيمان ابراهيم ارحيل الهرش
EMAN IBRAHIM IRHYAIL AL-HERESH
Journal Title
Journal ISSN
Volume Title
Publisher
AL-Quds University
جامعة القدس
Abstract
Several studies have been conducted to detect the direct effect of inhibiting the aromatase activity, the rate limiting enzyme that converts androgens to estrogens needed for ovarian differentiation in fish to overcome the immediate need for a more environmentally friendly substitute of methyl testosterone. Cyclooxygenase (COX2)- inhibitors are potent and irreversible inhibitors of the COX2 pathway and since studies on human breast cancer cells shows that they decrease aromatase messenger ribonucleic acid (mRNA) expression at the transcriptional level we tested the effects of supplementation of COX2-inhibitors (Etodolac and Etoricoxib) in the diets of fry tilapia on growth rate, and mortality.On the other hand, human and veterinary pharmaceuticals have been shown to occur in considerably high amounts in sewage treatment plant (STP) effluents and surface waters, with the non-steroidal anti inflammatory drugs representing one of the most commonly detected compounds. Information concerning possible ecotoxicological risks of these substances is rather scarce. So far there are no data available on their possible effects in fish after prolonged exposure. Thus, highlight on Etoricoxib pharmacokinetics was carried out by determination of Etoricoxib in fish feces using HPLC. The study was carried out at the Aquaculture research laboratory, in AlQuds University, Jerusalem. At an age of 8 days post – hatched 30 genetically mixed population of Oreochromis. niloticus larvae were stocked in duplicate, into aquariums each with a capacity of ≈ 45L in a closed system. Treatments included 5 different experimental diets and one standard diet serving as control with two repeats for each group from 0.5 % groups of diets. The test diets were prepared by mixing 600 mg of etodolac with 20g,60 g,30 g commercial feed, to achieve (0.5% etodolac,1%etodolac, 2% etodolac)concentrations respectivelythe same process was done to the etoricoxib by mixing 90 mg of etoricoxib with 18 g, 9 g, commercial feed, to achieve (0.5% etoricoxib,1% etoricoxib) concentrations respectively. Another experiment was conducted using 10 adult mixed populations at age of 2 months stocked in triplicate in a closed system and, treated as above. Feeding started on the same day of stocking and fish were fed once daily. Feed was adjusted according to fish weight, by 10 % of their weight during the first four weeks and 5% of their body weight after changes of all diets to control diet. Fish were weighted every week and counted in each aquarium to determine survival rate during 12 weeks period. Individual fish in each aquarium was weighted to the nearest 0.1 g using adigital scale. The growth rate (GR) was determined using linear regression: yt = a + bxt, where yt is the average total weight (g) of the fishes at time t and a is the average weight (g) of fishes at the start of the experiment. Results showed that the different growth rate parameters (final body weight, weight gain and growth rate (GR) of O niloticus fed with selective COX2 inhibitor Etodolac and Etoricoxib respectively were significantly affected with the highest growth rate obtained with the 0.5% etodolac followed by etoricoxib 0.5% followed by untreated sample. However, no increase or decrease of growth in mixed adult population was observed. Growth rate increased with increasing concentrations with the highest growth rate in the aquarium treated with (2% Etodolac) followed by (1% Etodolac), but (1% Etoricoxib) showed a decreased growth rate compared to standard which could indicates a toxic potential toward fish at this concentration. In addition, no peak for Etoricoxib was detected on HPLC in feces samples collected after half an hour, 1 hour, 2 hours, 3 hours and 4 hours,24 hours following treatment with 1% etoricoxib diet in 4 months age tilapia. This reflected, that Etoricoxib, was well absorbed by tilapia, extensively metabolized with no unchanged fraction excreted, or may undergo enter hepatic circulation, increasing further its toxic potential. No mortality was observed in adult mixed population. In fish fry there were no differences in mortality rates between (0.5% Etodolac), and (0.5% Etoricoxib) treatments, but survival rate (96.6% and 90%) were improved compared to control (86.6%, 83.3%) during the experimental feeding. Higher mortalities were shown as concentrations increase with (1%Etoricoxib), (1% Etodolac) and (2% Etodolac). These results indicated that the inclusion of selectiveCOX-2 inhibitor in fish diet efficiency was maximally exerted during critical period of sexual differentiation, which occurs in tilapia fry between 2 and 6 weeks after spawning. After finishing of this period there was no effect on the growth rate. Thus, COX inhibitors could modulate aromatase activity needed for proper sexual development and reproduction during the crucial period. Furthermore, this is the first time to our knowledge we test the effects of these agents on fry teleosts during the crucial period of sexual development which points to possible alterations in reproduction following chronic exposure to these drugs at an early stage in contaminated surface water. Subsequent field investigations in normal aquaculture bonds are needed to confirm these results in larger population, using different classes of COX-inhibitors at different concentrations. ,
Description
Keywords
الكيمياء الحيوية والاحياء الجزيئية, Biochemistry & Molecular Biology
Citation