Genetically altered alfalfa may soon give growers not one, not two, but three alternate uses for the crop.

Transgenic alfalfa can now produce phytase, which helps hogs and poultry utilize phosphorus while decreasing its levels in manure.

"The juice also contains a lot of good proteins and the pigmenting agent called xanthophyll, which makes egg yolks and poultry skin golden in color," explains Richard Koegel.

Koegel is an ag engineer at USDA's Dairy Forage Research Center, Madison, WI.

Alfalfa-produced phytase is expected to cost less than phytase made by microbial fermentations. And it may cost half the price of phosphorus supplements, says Koegel.

"Phytase allows poultry and swine to derive a lot more of the phosphorus from the grain in their diets. This means less supplementation and less phosphorus going out into the manure, which has become an environmental concern."

The enzyme showed positive results in two poultry feeding trials, but Koegel doesn't yet know exactly how much is needed in rations. Or how much it can cut phosphorus levels in manure.

"As far as having seed, I would say it's only about a year off. For it to become a commercial reality, that's going to depend on how fast the swine and poultry producers accept this as a good source of phytase."

They may choose other approaches to reducing phosphorus in manure and cutting supplementation costs. Low-phytic-acid corn hybrids will be on the market by 2000; phytase is also being made via microorganisms.

"But I think we can produce phytase very cheaply relative to some of the other methods."

Transgenic alfalfa is processed through a mill, then passed through a press to make juice. The juice can be added to feed or be processed further into xanthophyll or phytase concentrates.

"Poultry producers currently are spending a reasonable amount on materials such as marigold petals (for pigmentation)." Alfalfa-produced pigment will cost less, he hopes.

"We are challenged, though, to produce a stable, concentrated product. Xanthophyll oxidizes and deteriorates if not processed and stored properly."

Koegel is now working on ways to extract and concentrate phytase and xanthophyll at low costs and with less energy consumption.