Natural compounds found in a variety of foods — especially grains, beans, legumes — that interfere with the absorption of vitamins, minerals and other nutrients. They can get in the way of the digestive enzymes, which are key for proper absorption.
Apparent Digestibility Coefficient (ADC)
Percentage of nutrients in an ingredient that are readily absorbed in the digestive tract of fish.
Closed Formula Feeds
By contrast, Feeds produced by commercial feed companies are most often Closed-Formula: the exact ingredient composition and inclusion levels are proprietary. Often, the formulation of commercial feeds will change over time as feed producers introduce enhancements to nutrition and price. When multiple commercial diets are studied, fish farmers should realize that this is a “snapshot” in time since commercial feed companies could have changed their proprietary formula.
Commercial reference diet
This is a commercially available diet used to compare growth rates of fish fed experimental diets vs fish fed a commercially available diet.
Complete Diet protocols compare performance of fish fed diets that simultaneously vary nutrients and ingredients. An ingredient may have nutritional and economic value in a prior Ingredient Evaluation, but once it is included in a feed, it is considered a Complete Diet (CD), since the performance of fish is affected by all the ingredients in the formula and the nutrients represented (i.e. crude protein, lysine, methionine etc.).
Is the bland diet used to compare the fish physiology parameters resulting from test feed which includes the new ingredient.
The strength of feed pellet when exposed to physical impact.
Contains fishmeal and fish oil
Fishmeal or fish oil reduced
Fishmeal or fish oil free
Fishmeal and fish oil free
Refers to a feed pellet prepared in a way to stay on the water surface for the duration of the feeding period.
Refers to the growth stage/size of fish that has recently hatched from eggs.
Light blockage is often referred to as light obscuration. Light obscuration allows for high resolution particle sizing.
Open Formula Feeds
CDs composed of known ingredients, with known inclusion levels for each ingredient, are considered for the purposes of this paper, Open Formula feeds. Open Formula feeds are often developed by Academic Institutions and Government Research Agencies as tools for specific research projects or for use in Federal Hatcheries. Open Formulas allow direct comparison between feeds tested in different years and at different institutions because they can be fully replicated.
Commercial feeds are often used as ‘Reference Feeds’ since they provide a reference for what is commercially available at the time. A suitable reference feed should be commonly used by commercial producers for a particular species.
Consists of fish feces and any uneaten feed.
Fish species that can be used for feeding tests to evaluate new ingredients across the board. Note that the ingredient may not be originally intended for use in feed for the surrogate species, but surrogate species may nonetheless yield valuable information due to ease of handling, responsiveness to feed and growth conditions, that can inform decisions for species-specific feed design.
Testing Scale Description
Lab scale = less than 100 lbs
Demo scale = between 100 lbs and 3 tons
Pilot scale = between 3 and 5 tons
Commercial scale = more than 5 tons
Total Omega 3
This is the sum of all omega-3 (first carbon carbon double bond at carbon 3) fatty acids present in the product.