MISSISSIPPI STATE -- Feeding unfit food to broilers can cost a major poultry operation $90,000 a week, but a test has been developed to ensure quality products are fed to these birds.

Researchers at Mississippi State University's College of Veterinary Medicine developed a way to test fish and poultry by-products that are fed to broilers. The test detects biogenic amines, or toxins, produced when by-products deteriorate.

Certain bacteria in stored raw meat by-products change amino acids into toxins, such as histamines. These toxins can cause extensive intestinal disorders in broilers that eat the products, said Dr. Robert Keirs, a researcher at the veterinary college.

"The intestinal malfunctions don't kill the chicken, and they may not even appear sick," he said.

Keirs said the problem lies in the fact that the broiler no longer processes food efficiently. With the intestinal tract not functioning properly, the broilers need more nutrients than they are getting in the food.

Although the quality of the bird appears unaffected, its final weight may be less than expected.

Broilers' diets usually are composed of 3 to 4 percent fish and poultry by-products, with sometimes as much as 6 percent.

"By-products are fed to the broilers to supply necessary levels of essential amino acids not readily available through other feed materials," Keirs said.

In producing broilers, feed accounts for 70 percent of the total cost. But if the feed quality has deteriorated, the birds may digest inefficiently, with production costs rising even higher.

Yearly, Mississippi produces 700 million broilers. When broilers are not digesting food properly, producers often must feed them up to 5 percent more than normal to meet the birds nutritional needs.

"Biogenic amines in feed may cause serious financial losses in the broiler industry," Keirs said. "Growers have to use significantly more feed to produce the same broiler."

Keirs noticed this health problem while working with the veterinary college's avian health monitoring program.

"Broiler complexes using high levels of fish meal would often have birds with high levels of intestinal disturbance," Keirs said.

He then began working on the project with Dr. Lloyd Bennett, a chemist and MSU researcher. Together they developed a way to test for biogenic amine levels.

Today, the veterinary college is apparently the only lab in the United States doing commercial work that does this test. It is one of about 15 worldwide that tests for these toxins in by-products. At industries' request, they test by-products and broiler feed.

"We report the findings and they either interpret the information themselves or ask Dr. Keirs to make an interpretation," Bennett said.

Keirs said a major insight came in 1992 when it was found that broilers fed certain poultry by-products had severe intestinal problems. Keirs and Bennett associated this with inefficient handling of the by-products being used for feed.

This finding led to widespread industry reevaluation of how fish and poultry by-products are processed and made into feed.

"Companies have become much more careful with how they're rendering the by-products," Keirs said.

In addition to developing this test, the researchers established quality baselines for poultry by-products. They did this through a cooperative effort with five major by-product processing centers in the United States.

Future research will look at nutrient loss in deteriorating by-products.