Scientists have developed eggs that don't raise human cholesterol levels like regular eggs, and they are trying to prevent heart disease by identifying food chemicals that reduce blood cholesterol.

Both efforts at making diets healthier were outlined Monday at the annual meeting of the Federation of American Societies for Experimental Biology.Suk Y. Oh, an associate professor of nutrition, and colleagues at the University of Utah added fish oil to chicken feed. Hens that ate the oil-enriched feed for eight weeks laid eggs that reduced blood pressure and blood fats in a group of 12 people and, unlike regular eggs, didn't raise cholesterol levels.

The eggs taste and smell like fish, but Oh said that can probably be avoided by feeding hens deodorized fish oil.

If Oh's preliminary findings are confirmed in a larger study, "consumption of such eggs will not increase the risk of developing coronary heart disease" no matter how many are consumed, he said.

Oh said fish oil-enriched eggs could join existing low-cholesterol egg substitutes in markets by summer 1989, but because of the price of fish oil, the eggs would probably cost about 40 percent more than regular eggs.

The American Heart Association recommends people eat no more than 300 milligrams of cholesterol daily because high levels of the fat-like substance in blood are linked to increased risk of hardening of the arteries, heart attacks and strokes. A regular egg averages 274 milligrams of cholesterol.

In the other study, nutritional sciences professor Charles Elson and colleagues at the University of Wisconsin found that daily consumption of 140-milligram capsules of lemongrass oil, a spice common in Thai food, reduced blood cholesterol more than 10 percent in more than one-third of a small group of people with unhealthy high levels.

Elson now is testing other foods containing chemicals called isoprenoids to learn if they also can inhibit the body's formation of cholesterol from simpler fats.

"We're looking in beer, wine, citrus peel and oats," he said. "We've found a compound in barley. Any green plant has similar compounds, and some also are in milk. If we're correct, we could create a diet composed of a variety of foods containing factors that work together to control cholesterol."

For now, people should eat a wide variety of vegetables and fruits to "have ready access to compounds that will help block or reduce cholesterol synthesis" in the body, Elson said.