And This Little Piggie Went on a Diet
WASHINGTON (AP) _ Animal scientists who have produced lean, chic hogs known for their good looks and absence of excess tummy fat may be doing more than providing consumers with low-calorie pork chops.
The research has become so sophisticated that some are talking about new ways of examining unborn pigs and predicting whether they will be fat or lean when they grow up. Maybe, they say, the same can be done for people.
Gary J. Hausman, an animal physiologist for the Agriculture Department’s research center in Athens, Ga., says that he and his colleagues made a discovery involving a swine growth hormone and an enzyme when they compared blood and tissue samples from fetuses of genetically fat and lean pigs.
All of the fetuses of the fat pigs had lower levels of the hormone, coupled with higher amounts of a key enzyme, LPL or lipoprotein lipase, which acts as a ″gatekeeper″ by waiting on the walls of blood vessels to break down large fat molecules, allowing the fatty acids to pass through the wall into fat cells. The more LPL available, the more fat deposited in the body.
Hausman and a USDA colleague, Dennis R. Campion, and Roy J. Martin of the University of Georgia, shared in the discovery, which was recently reported by the department’s Agricultural Research Service.
″The swine growth hormone frees fat from storage, letting it be used to build muscle or other tissue,″ the report said. ″Depressed levels of the hormone mean more fat is stored, making for fatter pigs. Knowing that the hormone and enzyme levels associated with obesity can be found in the fetus means that genetic fatness in adult pigs can be predicted.″
Although the most immediate benefit of this research will be to help breed leaner pigs, Hausman believes it may be possible to extrapolate the findings to humans. As research models, pigs are closer to people than most other laboratory animals.
″Obese people are known to have excessive LPL of a type that closely resembles that of pigs,″ the report said. ″ The swine growth hormone indicator of fatness may also have a counterpart in people.
″If so, a simple blood test of infants would allow doctors to tell if children are predisposed to being fat. Parents could then work with nutritionists to plan special diets for their children.″
But even more important, the report said, is the possibility of creating food supplements that could counteract the genetic tendency to obesity in people and pigs.
No such magic supplement is yet available, but animal scientists continue the work of many years to come up with leaner foods for fat-conscious consumers.
Roger Gerrits, an animal production expert in the Agricultural Research Service, said one of the goals is to produce livestock with lean meat that has flavor and tenderness.
″You can’t remove all the fat, because fat is an important component in meat flavor,″ he said. ″Consumers want meat with less fat and farmers don’t want to spend money producing fat that consumers don’t want.″
Leaner meat has been a goal of agency scientists since the 1950s, said Gerrits, who worked years ago on evaluating the physiological differences betwen high- and low-fat lines of swine.
Meat animals are generally leaner today, he said, but the consumption of red meat - beef, ork, lamb, mutton and veal - has fluctuated and generally declined in the last 15 years. Between 1970 and 1985, per capita consumption of these red meats dropped from 151.6 pounds, retail weight, to 144.5 pounds.
But the consumption of leaner meats such as turkey, chicken and fish increased over the 15-year period. Per capita turkey consumption rose from eight to 12 pounds a year, while broilers rose from 36.8 pounds in 1970 to 54.9 pounds last year.
Gerrits said that increased awareness of fat in meat has contributed to these trends and has prompted agency scientists to increase their study of fat in meat and poultry.
″We’ve come a long way in reducing fat, but we still have these new areas to explore,″ he said.
Some of the current research projects include:
-A growth hormone that may help an animal make lean meat while reducing fat.
-Lowering of fat in chickens by putting six-day-old chicks on a restricted diet for six days. At the age of 12 days, regular diets were resumed. At slaughter, the eight-week-old birds had 25 percent less abdominal fat.
-Using light to stimulate cattle and sheep to produce growth hormones, raising the possibility of getting an animal to convert more feed into lean mean instead of fat.
-Introducing foreign animals that have less fat into U.S. breeding herds. One leaner breed of sheep, Texel, from the Netherlands is being tested at the present time. End Adv for Sunday, July 20, and Thereafter