DIETARY CHROMIUM PICOLINATE ADDITIONS IMPROVE GAIN FEED AND CARCASS CHARACTERISTICS IN GROWING-FINISHING PIGS AND INCREASE LITTER SIZE IN REPRODUCING SOWS/

Growth trials were conducted to determine the effects of Cr as chromiu m picolinate at various protein levels on performance of growing pigs. The effects of continued supplementation on sow fecundity and body we ight changes through two parities also were examined. In Trial 1, 48 c rossbred pigs (40.9 kg initial weight) were assigned to one of three d iets (0, 250, or 500 ppb of added Cr). The only observed difference wa s an overall tl:end for an improvement in gain:feed when Cr was added to the diet (P < .10). In Trial 2, 105 crossbred pigs (14.5 kg initial weight) were assigned to one of seven treatments involving a combinat ion of two factors: 1) lysine level at 100 or 120% of NRC (1988) requi rement estimate and 2) added Cr level (0, 100, 200, 500, or 1,000 ppb) . A Cr x lysine interaction (P < .02) for gain:feed existed that demon strated that the addition of 200 ppb of Cr resulted in improved gain: feed at the 100% of requirement lysine level but not at the 120% of re quirement lysine level. The addition of 200 ppb Cr also reduced backfa t (P < .04) and increased longissimus muscle area (P < .04) regardless of lysine level in the diet. Gilts were retained from Trial 2 to asse ss the effects of continued Cr supplementation on performance through two parities; gilts fed diets with 0 or 200 ppb of added Cr during the growth trial were continued on those levels and gilts fed diets with 500 or 1,000 ppb of added Cr during the growth trial were fed 0 ppb of added Cr through breeding and reproduction. Sows fed added Cr had lar ger litters (P < .03) than sows unsupplemented throughout life. Assess ment of pre- and postfeeding blood samples in mid-gestation revealed t hat serum insulin and insulin:glucose ratio were affected (P < .003) b y Cr supplementation, indicating greater efficiency of insulin action. Chromium from chromium picolinate produces favorable biological respo nses in swine.