Aquaculture

Permanent URI for this collection

http://dspace.alquds.edu:4000/handle/20.500.12213/96
Aquaculture

Browse

Browsing Aquaculture by Author "Al-Qutob, Mutaz A."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    The effects of COX-Inhibitors (Diclofenac and Ibuprofen) on growth rate, mortality and sexreversal in Nile Tilapia (Oreochromis niloticus)
    (Bioflux - bimonthly, 2009-10-30) Al-Qutob, Mutaz A.; Nashashibi, Tharwat S.
    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 (COX)-inhibitors are potent and irreversible inhibitors of the COX 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 hypothesis of possible aromatase inhibition by the non-selective COX-inhibitors in fry fish tilapia. The effects of supplementation of COX-inhibitors (diclofenac and ibuprofen) in the diets of tilapia on growth rate, mortality and sexual differentiation have been studied. 20 Genetically females (XX) (O. niloticus) larvae were stocked in triplicates in a closed system and each were given control diet (C group) and control diet supplemented with (10 mgKg-1) diclofenac (1% diclofenac group), (5 mgKg-1) ibuprofen (0.5% ibuprofen group), and (5 mgKg-1) (0.5% diclofenac group) respectively for 4 weeks. After the 4th week all diets were changed to control diet. At the end of 12-weeks, no significant differences were found in growth rate (GR) between diets (p>0.05). Mortality ranged from 1.67% +- 2.89 (SD, n=3) in control group to 58.3% +- 14.4 (SD, n=3) in the 1% diclofenac group during the experimental feeding and from 6.67+-2.89 (SD, n=3) to 63.3%+-10.4 (SD, n=3) at the end of 12-weeks period. 7% In the control group, 36% in the 1% diclofenac group, 17% in the 0.5% ibuprofen group, and 22.2% in the 0.5% diclofenac group respectively never produced egg during the entire experimental period. Macroscopically all the nonspawning fish in the experimental groups were females with apparently larger ovaries and full of eggs compared to control. Microscopically they were full of apparently normal eggs with morphology similar to those of control. Postulated mechanisms of action of the supplemented COX-inhibitors are discussed. Based on the above it can be concluded that the use of COX-Inhibitors during the crucial period could modulate aromatase activity and affect reproduction in Nile tilapia.
  • Thumbnail Image
    Item
    Utilization of desalinated brackish water residues for cultivation of the marine fish species,Dicentrarchus labrax, Sparus aurata, and Sciaenops ocellatus
    (Bioflux - bimonthly, 2013-01-19) Al-Qutob, Mutaz A.; Qubaja, Ra'fat A.; Nashashibi, Tharwat S.
    The utilization of brackish water residues from desalination units for fish mariculture in Palestine could represent an environmental friendly alternative of disposing brine water which could have an adverse effect on wild life. In this study, three juvenile marine fish species (Gilt-head bream S. aurata, European sea bass D. labrax, and red drum S. ocellatus) with average weights of 0.7-4.9 g, were acclimated and reared in brine brackish water residues collected from Jericho desalination units with salinities of 6.5 ‰ and 11 ‰ diluted sea water as control for 3-7 months. Fish were fed 56 % rich protein diet. Brine brackish water contained high levels of Cl-1 (3369 mgL-1), Na+1(3735 mgL-1), K+1(300 mgL-1), SO4 -2 (716 mgL-1) with the divalent ions Mg+2 (57.3 mgL-1) and Ca+2 (276 mgL-1).The experimental well showed more than the maximum allowable concentration of Cr (14.49 μgL-1), Ag (5.3 μgL-1) and Mn (27.88 μgL-1) for water quality of fisheries use. The sea bass with an average weight of 0.76 g (at a salinity of 6.5 ‰) showed an acceptable growth performance parameters and reached a percentage weight gain (% WG) of 6345.23 % and a survival rate of 77.5 % compared to control groups at 11 ‰ that reached at the same time a % WG of 6543.78 % and a survival rate of 82 % after 30 weeks. The red drum juveniles reached a % WG of 2661.6 % and 2673.92 % after 15 weeks at 6.5 ‰ and 11 ‰ respectively while sea bream reached a % WG of 241.63 % and 772.44 % after 15 weeks at 6.5 ‰ and 11 ‰ respectively. Survival rate was only 5 % at both salinities for the two species. In a further study sea bass fingerlings with an average weight of 20.5 g were reared in brackish water of 6.5 ‰ salinity for 7 weeks and were fed superior fish meal with fish oil. They received diets of 2.1 %, 3.0 %, and 4.0 % of body weight. Sea bass fingerlings which received diets of 2.1 %, had the highest FCE (0.82) and PER (1.46) with the lowest FCR (1.22). These results confirm that the most suitable fish for cultivation utilizing brackish water from Jericho desalination units with salinity of 6.5 ‰ is sea bass D. labrax, while the other two species need some modification to acclimatize to this water. Furthermore, the best food % for optimum growth of sea bass at this salinity is 2.1 % after 7 weeks. Brackish water from Jericho desalination units are suitable for cultivation of these species, but may need some modification as adding salts to fish diet or water and reducing toxicity of some high trace metals present by a suitable method.