Eight experimental diets were formulated for rainbow trout using agricultural byproducts as major ingredients. Each experimental diet contained varying amounts of corn grain, corn gluten meal, corn gluten feed and one of the following: 200 g kg⁻¹ peanut meal, 200 or 400 g kg⁻¹ soybean meal (SBM), 390 g kg⁻¹ low-allergen soy flour, 310 g kg⁻¹ soy protein concentrate, 300 g kg⁻¹ low-allergen soy protein concentrate or 200 g kg⁻¹ SBM + 110 g kg⁻¹ blood meal. One diet contained 200 g kg⁻¹ SBM and canola oil as the main lipid source. The remaining diets contained 95 g kg⁻¹ menhaden oil. Fish fed a commercial trout diet exhibited significantly greater weight gain (322%), and a lower feed conversion ratio (0.89) but significantly lower protein efficiency ratio (2.18) than fish fed the experimental diets. Within the experimental diets, fish fed the 400 g kg⁻¹ soy flour diet and the 400 g kg⁻¹ soybean meal diet had significantly higher weight gains (276% and 268%) and protein efficiency ratios (2.58 and 2.52), and lower feed conversion ratios (1.02 and 1.03) than fish fed other experimental diets. Fillet flavour varied between treatments. Most notable was the lower fishy flavour and higher chicken flavour of fish fed the diet that contained canola oil rather than menhaden oil. Microscopic evaluation of the liver and five sections of the gastrointestinal tract failed to demonstrate any differences between treatment groups. The ingredient costs of several experimental diets were lower than the estimated cost of a standard commercial trout diet. However, the superior feed conversion ratios of fish fed the control diet resulted in lower feed costs per unit of fish produced.

Ten experimental diets and one control diet were fed to 720 tilapia (20 fish × 12 cages × three replicates) in a recirculating aquaculture system to determine the economic significance of replacing fishmeal with fishmeal analogs if the fishmeal analogs were processed on-site by the producer. All experimental diets were produced at Illinois State University using an Insta-Pro Model 600 Jr. extruder plus grinding, weighing and mixing equipment commonly found on commercial livestock operations. Primary diet protein sources included corn gluten meal, corn gluten feed and distillers dried grains. All diets were balanced for amino acid requirements of the fish, and both 32 and 36% crude protein diets were fed. There was no significant difference in feed conversion ratio (FCR) between diets with fishmeal and diets without fishmeal. There was no significant difference in FCR between 32 and 36% crude protein diets. An economic engineering model which included all equipment necessary for extruding and handling pelleted feed on-site was developed. Annualized investment and operating costs were estimated to determine the total cost of processing each of the 10 experimental diets. There was a significant difference in cost of gain among the 10 experimental diets and the control diet. Cost of production was highly sensitive to volume of feed extruded.

AQUI-S is a fish anesthetic/sedative that is approved for use in a number of countries throughout the world and has the potential for use in the United States. The active ingredient in AQUI-S is isoeugenol. A method for determining isoeugenol concentrations in edible fillet tissue is needed for regulatory purposes, including surveillance and potential use in studies fulfilling human food safety data requirements if U.S. Food and Drug Administration approval is pursued. A method was developed and evaluated for determining isoeugenol concentrations in fillet tissue using relatively common procedures and equipment. The method produced accurate and precise results with fillet tissue from 10 freshwater fish species. The percentage of isoeugenol recovered from samples fortified with isoeugenol at nominal concentrations of 1, 50, and 100 g/g for all species was always >80 and <97. Within-day precision for samples fortified at those same concentrations was 10, and day-to-day precision was 4.0. Method precision with fillet tissue containing biologically incurred isoeugenol was 8.1. There were no or minimal chromatographic interferences in control fillet tissue extracts from 9 of the 10 species. The method detection limits for all but one species ranged from 0.004 to 0.014 g/g, and the quantitation limits ranged from 0.012 to 0.048 g/g.

Recirculating Aquaculture Systems (RAS) use less water than open pond systems and the concentrated wastes generated by fish in RAS are easier to collect and reuse. High operating costs limit RAS use to high-value species production. One strategy to improve productivity and offset the high operating costs is to convert the solid waste from the aquaculture systems to more valuable byproducts.

Are you considering aquaculture as a new business or as a way of diversifying your existing business? If the answer to this question is yes, then you should ask yourself, "How much do I really know about aquaculture?"

There are many levels of knowledge of aquaculture - from the person who has many years experience in running a successful aquaculture operation, to the beginner who has an interest in, but really no knowledge of, what aquaculture is or involves. This publication, A Basic Overview of Aquaculture, is directed to those who have an interest in aquaculture, but who lack knowledge about it or experience in the business. The reader should note that this publication is not intended to be a complete introduction to aquaculture. It does not cover many important topics such as stocking, feeding, harvesting, transport, marketing, and others. In addition, the topics that are covered are not complete. Instead, the intention here is only to introduce some aspects of aquaculture.