Appetite Hormone Puts
Pigs on Faster Growth Track
By Ben Hardin
September 16, 1999
Of every 10 pigs born alive, at
least one dies within days and others may grow more slowly than their
littermates. Those that thrive, however, generally gain more weight per pound
of feed after weaning and have less carcass fat when they go to market.
Mindful that getting more pigs off to a good start could improve production
efficiency, ARS scientists are
researching hormones to find ways to enhance pigs appetites, manage
stress and reduce sickness and deaths. Just shortening by one day the average
time from birth to market could lower housing and feeding costs enough to boost
annual net income for the nations swine producers by tens of millions of
In one experiment, researchers at
Mo., found that a single injection of the hormone orexin-B into 3-week-old
pigs increased feed intake 18 percent, though only for a short time. More
research is underway to find whether two or more well-timed injections can
improve growth rates enough to be worthwhile.
Someday farmers may inject pigs, not with orexin-B, but with less expensive
synthetic versions of it. Or a gene therapy may be developed to make pigs
produce more of their own orexin.
Besides affecting appetite, hormones--in complex ways--exert major impacts
on swine during stress in production environments. During birth, for example,
stress may help pigs prepare for life beyond the womb. Research showed blood
and tissue samples of pigs that came into the world by caesarean section had
strikingly different hormone levels than pigs born naturally. Two weeks later
more similarities and differences appeared, giving insights on lasting effects
of birth experiences.
ARS is USDAs chief scientific
An article about the research appears in the September issue of Agricultural Research magazine
and online at:
Scientific contact: Robert L.
Matteri, ARS Animal Physiology
Research Unit, Columbia, Mo., phone (573) 882-1047, fax (573) 884-4798,