USE OF KRILL HYDROLYSATE AS A FEED ATTRACTANT FOR FISH LARVAE AND JUVENILES

S. Kolkovski, S. Czesny, K. Dabrowski-2000

Journal of the World Aquaculture Society, 31 (1): 81-88 (from Current Contents)

Abstract:

We determined the effect of krill hydrolysate as a feed attractant in three freshwater fish species: yellow perch Perca flavescens, walleye Stizostedion vitreum, and lake whitefish Coregonus clupeaformis. Growth trials were conducted using a commercial trout starter diet (control) and the diet that was coated with liquid krill hydrolysate. The krill hydrolysate coated diet increased growth of yellow perch juveniles by 31% compared to control diet (average final wet weight, 734 +/- 33 mg and 559 +/- 82 mg, respectively). Moreover, weight gains were not significantly different than for fish fed exclusively live Artemia nauplii. Similar results were obtained with walleye juveniles fed either a trout starter diet or 5% krill hydrolysate coated diet (8.9 +/- 0.25 g and 11.6 +/- 5.1 g wet weight, respectively). The food conversion ratio (FCR) was lower in fish fed the control diet, although not significantly different (2.95 +/- 0.18 and 3.69 +/- 0.39, for control and coated diet, respectively). The effect of krill hydrolysate on dry diet ingestion rates of lake whitefish and yellow perch larvae was also determined using radioactive (C-14) labelling. A commercial starter diet was coated with krill hydrolysate or the soluble fraction of krill hydrolysate was added to the experimental tank water. In both species, coating the diet with 5% krill hydrolysate resulted in significantly higher ingestion rates. Supplementation of krill hydrolysate soluble fraction to the tank water resulted in 200% increase in ingestion rate in comparison to control (uncoated starter diet), although it was not significantly different from krill coated diet and live Artemia nauplii ingestion rates.

(Ohio State Univ, Sch Nat Resources, Columbus, OH 43210, USA)

home