Location: Aquatic Animal Health ResearchTitle: A game of keep-away: feeding the fish and not the pond
|PEATMAN, ERIC - Auburn University
Submitted to: Aquaculture Miscellaneous Publications
Publication Type: Popular Publication
Publication Acceptance Date: 11/30/2015
Publication Date: 12/2/2015
Citation: Peatman, E., Beck, B.H. 2015. A game of keep-away: feeding the fish and not the pond. Fish Farming News. p. 4.
Technical Abstract: Phytic acid is a storage form of phosphorus in many plants. Its levels rise in the diet along with the inclusion rate of plant-based materials. Our measurements have found that phytic acid levels can be as high as 2% of catfish diets (40 lbs/ton of feed). However, phytic acid is largely indigestible by mono-gastric animals (pigs, chickens, fish), passing straight through the fish and ending up contributing to phosphorus levels in the pond. Within the last five years, however, phytic acid has been found to not only be a source of phosphorus pollution, but also to be a potent anti-nutrient, a feed substance which can negatively impact animal health and growth. Phytic acid in the diet binds up minerals (iron, zinc, etc) and amino acids intended and needed for fish health and growth. Recognizing the problem that phytic acid poses in plant-based diets, poultry and swine producers have made it common industry practice to add the enzyme phytase to their feeds. Phytase cleaves up phytic acid in the stomach, freeing up its phosphorus for uptake by the fish and destroying its ability to bind up other dietary elements. Our tests have found that phytase is working as described, significantly reducing phytic acid levels in the gut, and significantly boosting mineral retention, particularly iron, compared to a normal catfish diet.