Laserfiche WebLink
<br />! <br /> c. <br /> :...-:) <br /> I i';l <br /> I <br /> .I ,.;:,. <br /> .....' <br />.. i ....:t <br />.. <br /> <br />\ <br /> <br />~ <br /> <br />4.4 mg/kg body weight after growth measurements and muscle plugs were taken, The sexes <br /> <br />were then separated by placing all males of a given treatment in one tank and all females of the <br /> <br />same treatment in the two remaining tanks for that treatment <br /> <br />Starting with the control fish, individual males were anesthetized in a bath containing <br /> <br />tricaine methanesulfonate (MS-222, Argent Chemical, Redmond, W A) at 100 mgfL and then <br /> <br />manually stripped. The milt was collected in 50-m! plastic centrifuge tubes and placed in an ice <br /> <br />bath. The fish was placed in a tank of clean test water (i.e., without selenium) until it regained <br /> <br />equilibrium and then it was returned to the exposure tank. After all males of a given treatment <br /> <br />were stripped, the females were checked. Each female was anesthetized as above and an attempt <br /> <br />was made to manually strip the eggs. If the female expressed eggs, they were collected in a <br /> <br />2-L stainless steel bowl containing about. I 00 ml of sperm extender solution prepared by adding <br /> <br />12 g of Dilueur 523 (Sanofi,Sante Nutrition Animale, Liboume, France) to I L of clean test <br /> <br />water at 22-230(, <br /> <br />We intended to cross the two females in a given tank with the male from the same tank, <br /> <br />If the male did not express a sufficient amount of milt, the eggs were fertilized with sperm from <br /> <br />a male of the same treatment Milt from one male was added to the eggs and the gametes were <br /> <br />gently stirred with a large feather for about I minute, during which about 250 mI of clean test <br /> <br />water was added to activate the sperm. After fertilization, about 250-500 ml of a bentonite clay <br /> <br />sluny was added to the bowl and stirred for about I minute to counteract adhesiveness and <br /> <br />prevent clumping of the eggs, The egg mass was divided between two medium size fine-mesh <br /> <br />dip nets and thoroughly rinsed in clean test water. The eggs were then submerged in a container <br /> <br />of clean test water to water-harden for at least I hour. <br /> <br />After water-hardening, total number of eggs expressed by each female was estimated <br /> <br />15 <br />