Chromium was discovered more than 200 years ago, but has been getting increased attention recently for both human and swine diets.

According to the National Research Council (NRC), chromium is thought to be essential for activating certain enzymes and for stabilizing proteins and nucleic acids. Chromium seems to be important for proper metabolism of carbohydrates, proteins and lipids.

Researchers are learning more about chromium all the time, yet much remains to be discovered. Chromium is believed to enhance the effectiveness of insulin. Most conclusions reached about chromium, so far, have been gained through research and clinical investigations with humans and laboratory animals.

According to NRC, research with animals has confirmed that chromium from dietary organic complexes, such as chromium tripicolinate, chromium nicotinate and high-chromium yeasts, is absorbed more efficiently than is chromium from chromium chloride.

Research studying growing-finishing pigs response to chromium has been somewhat inconsistent, says NRC.

Recent research with chromium tripicolinate has suggested potential benefits for use in diets for sows and gilts. Work completed to date has demonstrated significant improvements in sow productivity through enhanced litter size, farrowing rate and sows bred within seven days after weaning.

University of Kentucky researcher Merlin Lindemann found in 1995 that chromium tripicolinate could improve sow productivity by increasing litter size. Australian research conducted in 1996 and 1997 by Roger Campbell used a series of four studies with over 4,000 sows to suggest chromium tripicolinate could result in more sows bred within seven days of weaning. Based on data from that research, Campbell concluded the use of chromium tripicolinate in breeding herd diets would improve sow productivity by 0.4 to 1 pigs/sow/year.

Lindemann recently conducted additional research in which 12, 4,000-sow commercial units were assigned to one of two dietary treatments. The treatments included 0 or 200 ppb supplemental chromium from chromium tripicolinate.

Following a six-month 'loading' period, reproductive performance was evaluated over a 12-month test period. Lindemann found dietary supplementation of 200 ppb chromium from chromium tripicolinate had a positive impact on sows bred within seven days postweaning, number of pigs born alive and weaned and sow mortality. Lindemann found that sow productivity increased by 0.7 to 0.8 additional pigs/sow/year with chromium. The non-chromium group had 10.05 pigs born alive/litter average, while the chromium group averaged 10.42 pigs born alive/litter.

Sows in the chromium group had an average 5.90-days wean-to-first-service interval, compared to 6.38 days for the non-chromium group. Pigs weaned/sow showed an average 9.08 pigs for the chromium-supplemented group, and 8.75 pigs weaned/sow for the non-chromium group. There was a 1.5-1.6% reduction in death loss for the chromium-supplemented group of sows.

The 'loading period' seems to be important for efficient use of chromium, says Lindemann. During the loading period, sows and replacement gilts are fed chromium to help the animals build body chromium stores. The loading period Lindemann used was six months for sows (in production) and from at least 150 lb. to breeding age for replacement gilts. The sow performance between the control and experimental groups did not differ during the loading period, Lindemann reported.

Little research has been done in swine regarding decreased death loss among pigs fed chromium. However, both broiler and mouse work shows significant decreases in mortality among chromium-fed animals, according to Beth Kegley, University of Arkansas. Kegley speculates the decrease in death loss may be due to chromium's impact on insulin, which in turn stimulates immune response.

Although it is early to draw definite conclusions, it seems producers with some disease challenges in their operations may see more dramatic improvements from chromium use than would higher-health herds. The researchers agree good recordkeeping is crucial to measuring the success of any new dietary treatment.

NRC produced a 1997 report regarding the role of chromium in animal nutrition. They concluded that a decision to use supplemental chromium in practical swine diets should be based on potential benefits for a producer's specific situation as weighed against the costs of supplementation. Chromium tripicolinate was approved for use by the FDA's Center for Veterinary Medicine in 1996.