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April 18, 2005

Yang’s New Study Finds Milk, Beef
From Cloned Animals Safe to Eat

Ever eaten the perfect steak and wished all steaks could be as tasty? Well, cloned sirloins that might solve that problem could be just around the corner.

A study by a research team from UConn and the Kagoshima Prefectural Cattle Breeding Development Institute (CBDI) in Japan has found the strongest evidence to date that beef and dairy products from cloned cattle are safe for human consumption.

Jerry Yang and Peter Nicholls
Jerry Yang, professor of animal science, left, speaks with Provost Peter Nicholls at the welcome reception for Nicholls April 7 at the Benton Museum

Photo by Jordan Bender

The study, funded by the U.S. Department of Agriculture and Connecticut Innovations Inc., is the first to examine specific proteins and nutrients in the milk and meat from somatic cloned animals. It fills an important gap in the scientific literature, and may lead to regulatory approval of clone-derived food.

The researchers, led by Xiangzhong “Jerry” Yang, professor of animal science and director of Center for Regenerative Biology, Cindy Tian, also a faculty member of the Center for Regenerative Biology, and Chikara Kubota of the Kagoshima Prefectural Cattle Breeding Development Institute, reported their findings in the April 11 issue of the Proceedings of the National Academy of Science.

Debate has surrounded whether it is safe to eat cloned livestock and their offspring, and no food products from clones have yet entered the food chain in any country. The new study comes as the U.S. Food and Drug Administration (FDA) is poised to rule on whether to allow food from cloned livestock to be sold for human consumption.

“The data generated from our experiments provide new science-based information desired by regulatory agencies to address public concerns about the safety of meat and milk from somatic animal clones,” says Yang. “Information on the composition of meat and milk from somatic clones of food animals is extremely limited and highly desired.”

The research team used somatic cell nuclear transfer (the same technique that led to the 1996 birth of Dolly the sheep in Scotland) to clone a Japanese Black beef bull and a Holstein dairy cow.

Somatic cell cloning involves creating embryos with genes from a donor and eggs from other cattle. The nuclei of somatic cells from the donor are transferred into unfertilized eggs that have had their nuclei removed. The resulting new cells contain the entire DNA sequence of the donor chromosomes. The cells are then implanted into the wombs of surrogate cows.

Six bull beef clones were produced in 1998 and 1999 at CBDI from a famous 17-year-old Japanese breeding bull with superior marbling traits. And 10 dairy clones were produced at UConn from skin fibroblast or ovarian cumulus cells of a 13-year-old, high milk-producing Holstein cow in 1999.

Two bull clones were slaughtered for meat and four dairy clones were used to produce milk. The scientists compared the meat and milk from the clones to that of animals of similar age, genetics, and breed created through natural reproduction.

Analysis of protein, fat, and several other variables routinely assessed by the dairy industry revealed no significant differences in the milk. The researchers also examined more than 100 parameters concerned with meat quality. Results showed that all meat parameters examined for the cloned beefs fall within the beef industry’s standard ranges, and most parameters (more than 90 percent) were not different from those of the comparison animals.

This report lays some of the groundwork for larger more conclusive studies with cloned animals from a broad spectrum of genetic backgrounds, says Yang: “The experiments presented here are a pilot study to provide guidelines for more conclusive studies with larger numbers of clones from different genetic backgrounds, in order to further increase consumer confidence concerning product safety of somatic cloned food animals.”