Interpretive Summary: Effects of increasing concentrations of an Escherichia coli phytase on the apparent ileal digestibility of amino acids and the apparent total tract digestibility of energy and nutrients in corn-soybean meal diets fed to growing pigs.
By: Surely Wallace
In an article published in July 2018 in the Journal of Animal Science, researchers added bacterial Escherichia coli phytase to pig feed. Their aim was to determine if phytase could increase the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients in a corn-soybean meal (SBM) diet in growing barrow pigs. They hypothesized that digestibility would increase with increasing concentration of phytase.
Escherichia coli phytase is a microbial enzyme that breaks down phytate-nutrient complexes. Phytate is a natural component in plants that binds to nutrients, reducing digestibility. Microbial phytase has been used in animal feed to increase digestibility of phosphorus and calcium. Other nutrients may also benefit, however are not well studied.
In this study, 24 growing pigs were given one of 6 diets (within two periods) for a total of 8 replicates per diet. Each pig was fitted with T-cannula for access to the distal ileum. The feeding period lasted 14 days. Diets included (1) positive control corn-SBM diet with dicalcium phosphate, (2) negative control corn-SBM diet without dicalcium phosphate, and (3) corn-SBM negative control diet with added microbial phytase at a concentration of 500, 1000, 2000 and 4000 FTU. Digesta was collected on days 13 and 14. The aim was to determine apparent ileal digestibility (AID) of crude protein (CP), amino acids (AA) and the ATTD of gross energy (GE), dry matter (DM) and several minerals.
The authors reported a significant increase in the ATTD of calcium, iron, phosphorus, potassium, and magnesium with increased phytase concentrations. There was no significant effect on the ATTD of GE, DM, or other minerals, or the AID of CP or AA.
In conclusion, this study supports that addition of microbial phytase to corn-SBM pig feed may potentially be useful in increasing digestibility of several minerals. Such effects may have an economic benefit, as the authors point out that increased digestibility allows reduced dietary provision of these minerals. Overall, a larger study looking at the effects of microbial phytase on different kinds of feed, different pig breeds, or in higher concentrations may be warranted.
To view the full article, “Effects of increasing concentrations of an Escherichia coli phytase on the apparent ileal digestibility of amino acids and the apparent total tract digestibility of energy and nutrients in corn-soybean meal diets fed to growing pigs,” visit the Journal of Animal Science.