Effect Of Feed On Length Growth Of Rainbow Trout (Oncorhynchus Mykiss, Walbaum, 1792) In Cages

Abstract

The experiment was carried out at the cage farm “Tropic ribarstvo” (reservoir lake Bocac, 50km far from Banja Luka) in two cycles with 6 treatments and 90 days per cycle (180 days). The aim of the experiment was to analyze the effect of feed type on the length growth of rainbow trout reared in cages. All applied feed types had no significant effect on the mean length growth during autumn and winter probably due to the decrease of water temperature and level of feeding that was justified by a low length growth rate of individuals. Feed with higher content of row fat had a optimal effect on mean body length in spring and summer and showed significant differences of mean body length ( = 0.05;  = 0.01) compared to treatment 1 that had a lower fat and higher carbohydrate content. There was no significant difference between the mean length growth of rainbow trout using feed with 22 and 26 % of fat. Analyzing the season in relation to the feed type (F test) a very significant difference of mean body length was confirmed ( = 0.01), showing that the body length is highly dependent on the season and the feed type.