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A method for assessment of the effectiveness of feeding stimulants for salmonid fish: trials with krill (Euphausia pacifica) hydrolysates

University of British Columbia

A procedure was devised to assess the efficacy of processed krill (Euphausia pacified) products as potential feeding stimulants for rainbow trout (Oncorhynchus mykiss) in a diet containing 60% plant material. Three experiments were conducted. Test substances were added in substitution for, on a dry weight basis, 2% of the fishmeal in the control diet, and were either mixed into the diet prior to pelleting, or coated on the pellet surface. Fish were fed to satiation once daily. Feed intake and wastage were measured in one-minute intervals by feeding from separate containers in each minute of feeding and counting the number of uneaten pellets at the tank bottom after each minute. Feed was dispensed using a plastic spoon to prevent scent/flavour contamination of the diets. All the products, with the exception of two commercial preparations, resulted in 1) an increase in the rate and amount of feed consumed, 2) increased growth and 3) decreased feed wastage relative to the control diet. Coating of pellets with the products enhanced the effects, and resulted in the highest feed intake in all three experiments. In all experiments the rate of feed intake was highest in the first minute of feeding and declined rapidly until satiation was reached. Differences in feed consumption were evident in the first minute of feeding, and in the first 5 days of the feeding trial. Wastage was negligible in the first two minutes of feeding, but increased as satiation was approached. Less palatable diets were wasted earlier in the feeding process. The benefits yielded from the use of feeding stimulants appear to be long term. Measurement of feed consumption rate and wastage increased the sensitivity of the technique and yielded consistent and repeatable results.

Thesis/Dissertation

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2009-03-16

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http://hdl.handle.net/2429/6073

Animal Science

University of British Columbia

UBCV

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