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Salinity effects on osmoregulation and growth of the euryhaline flounder Paralichthys orbignyanus. 鹽度對廣鹽性比目魚 Paralichthys orbignyanus 之 滲透壓調節與成長影響. Introduction. Paralichthys orbignyanus. Family : Paralichthyidae Order : Pleuronectiformes Class : Actinopterygii - PowerPoint PPT Presentation
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Salinity effects on osmoregulation and growth of the euryhaline flounder Paralichthys
orbignyanus
鹽度對廣鹽性比目魚 Paralichthys orbignyanus之
滲透壓調節與成長影響Lui's Andre´ Sampaioa , Adalto
Bianchinib,*
Journal of Experimental Marine Biology and Ecology269(2002) 187-196
Reporter:Hui-ting Zhuang
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Paralichthys orbignyanus
• Family : Paralichthyidae• Order : Pleuronectiformes• Class : Actinopterygii• Max. size: 50.0 cm NG
(male/unsexed; Ref. 36453); 38 cm TL (female)
• Environment: demersal; oceanodromous (Ref. 51243); brackish; marine; depth range 1 – 45 m
• Climate: subtropical; 23°S - 41°S
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• Distribution: Coastal and estuarine waters of Western South Atlantic Ocean (Brazil , Uruguay and Argentina)
• High market price. • Wide tolerance to environmental factors such as salinity(0-
40‰), pH , and nitrogenous compounds and acid stress.
To evaluate the effect of hypo-(freshwater) and hyperosmotic (seawater) conditions on survival and growth.
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• Isosmotic point(等滲點 ) : 血漿中滲透壓與外界滲透壓相等的點。
• Isoionic point(等離子點 ) : 血漿中離子濃度與外界離子濃度相同時的點。如果魚生活在水中的鹽度,可以達到等滲點鹽度或是等離子點鹽度,魚就不用在耗費太多的能量調節滲透壓與離子濃度,也可以達到比較高的成長率。
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馴養 5 天 馴養 3 天適應鹽度分別為 0‰,10‰20‰,30‰and 40‰
實驗飼養 15天
Average weight=176.0±19.5g
1000-l鹽度維持在 33‰22±1°C海水12L/12D
餵食活的鯔科仔稚魚
300-lSix fish per tank餵食活的鯔科仔稚魚
自來水 (0‰) 濃縮海水 (50‰)
每天以虹吸的方式抽出排泄物,更換 50%的水。
取出樣本
上升到 50℃ 加速曝氣
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在不同鹽度中馴養 15天後的魚,以 50ppm benzocain( 苯坐卡因 ) 麻醉,抽出 1ml 的血,離心後,將血漿保存在液態氮中。
Osmotic analysis Ionic analysis
Anion (Cl-) 利用titration( 滴定法 )
Cations(Na+,k+,Ca2+)
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Growth studies
500-l鹽度維持在 30‰
放置一星期使比目魚適應鹽度定量餵食
500-l鹽度維持在 30‰
500-l在一星期內逐漸適應
鹽度降到 0‰
X2
X2
•14 flounders per group.•Water temperature was kept within 22±1°C. •12L/12D•一天餵食 4 次 .•排泄物以虹吸方式抽出,每日換水 30 %.
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Specific growth rate (SGR) =[( ln wf - ln wi ) / t x 100]wf = final weight (g)wi = initial weight (g)t = time (days).
0 30 60 90
麻醉,測量體長、重量
麻醉,測量體長、重量
麻醉,測量體長、重量
麻醉,測量體長、重量,取出腮及血
EX :wf = 38.85 (g)wi = 29.19 (g) t = 30 ( 天 )SGR = [( ln 38.85 - ln 29.19 ) / 30 x 100] = 0.953 %
( 天 )
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• Blood : Osmolality and ionic composition (Na+ and Cl- ).
• Gill : Na+,k+ ATPase
Glass Teflon Potter homogenizer
2 ml (250mM sucrose 20mMEDTA and pH7.4 Tris- HCl
buffer)
3°C 1000 x g for 20min腮絲
Bianchiniand Castilho (1999)Castilho et al.(2001)
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等離子點鹽度
Na+ 11.6 ‰
Cl- 8.4 ‰
K+ 22.6 ‰
Ca2+ 15.7 ‰
可推估Paralichthys orbignyanus 是廣鹽性的魚類。
等滲點鹽度滲透壓 10.9 ‰
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Growth studies
• No significant between replicates for both flounder survival and growth over 90-day test.
• Survival was not significantly affected by salinity, since, at the end of the 90-day test, it was 92.9 % in both freshwater and seawater.
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• The isosmotic point of P. orbignyanus was estimated as 328.6 mOsm kg-1 H2O and corresponded to 10.9‰ salinity.
Stenohaline freshwater teleosts Stenohaline marine teleosts
260 mOsm kg-1H2O 330 mOsm kg-1H2O 370 mOsm kg-1H2O 480 mOsm kg-1H2O
P.orbignyanus
321 mOsm kg-1H2O( 0 ‰ )
370 mOsm kg-1H2O( 40 ‰ )
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• It is described that environment stressors such as salinity can effect fish growth (Borski et al.,1994).
淡水中 P.orbingnyanus的成長率比海水中 P.orbingnyanus的成長率小
。
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學名;俗名 可以忍受的鹽度Paralichthys.
orbignyanus 0 – 40 ‰
Paralichthys. lethostigmaSouthern flounder
對鹽度耐受力隨年齡成長而增加,在完全變態後,可以生活在鹽度 0‰中。
Paralichthys.dentatusSummer flounder
5 – 50 ‰在仔稚魚階段對鹽分的耐受力達到最高。
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• P. orbignyanus can be characterized as a marine/estuarine euryhaline teleost capable of carrying hyper/hypo iono- and osmoregulation over the fluctuating salinity regime faced by this species in the environment.
• Long-term exposure to freshwater induces a reduction in growth rate of P. orbignyanus, possibly due to an increase in energy expenditure associated to the osmo- and ionoregulation under this salinity condition.
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