The Israeli Journal of Aquaculture - Bamidgeh 55(2), 2003, 132-138

GROWTH AND FEED CONSUMPTION OF
YOUNG RAINBOW TROUT (ONCORHYNCHUS MYKISS)
EXPOSED TO DIFFERENT PHOTOPERIODS


Sebahattin Ergün, Murat Yigit* and Ali Türker

Faculty of Fisheries, Department of Aquaculture, Ondokuz Mayis University, Sinop 57000, Turkey

(Received 14.1.03, Accepted 25.1.03)

Key words: feed consumption, growth, photoperiod, rainbow trout

Abstract

A feeding experiment was carried out in a brackish water (18 ppt) flow-through system to determine the effects of different photoperiods (light hours/dark hours; L/D) on feed intake and growth performance of young rainbow trout (Oncorhynchus mykiss). Duplicate groups of fish (35.32 g avg body wt) were exposed to a natural photoperiod, a long photoperiod (16L/8D) or a continuous photoperiod (24L/0D) for 60 days and fed to satiation twice a day. The growth rate, daily feed intake and feeding rate in the natural photoperiod were significantly lower (p<0.05) than in the long and continuous photoperiod groups. Growth was highest in the continuous photoperiod, but did not significantly differ from the long photoperiod. The feed conversion ratio, feed efficiency and gross efficiency in the long and continuous photoperiods were slightly better (about 5-7%) but did not significantly differ (p>0.05) from the natural photoperiod. Survival was not significantly (p>0.05) affected by the treatment. For better growth and a lower food conversion rate, the long photoperiod is recommended for young rainbow trout.


*Corresponding author: Fax:+90-368-2876255, e-mail: muratyigit@ttnet.net.tr

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