Effects of Fiber and Virginiamycin on Nutrient Absorption, Nutrient Retention and Rate of Passage in Growing Swine
- V. Ravindran,
- E. T. Kornegay and
- K. E. Webb
Three balance trials, each involving 12 crossbred gilts averaging 35.2 kg body weight, were conducted to determine the effects of dietary fiber and virginiamycin on nutrient digestibility, mineral absorption and retention, and digesta rate of passage (RP). Two levels of fiber (13.5 and 20.2% neutral detergent fiber) and two levels of virginiamycin (0 and 11 ppm) were used in a 2 × 2 factorial arrangement of treatments. All diets were isonitrogenous and isocaloric. The RP was determined by observing the time required for a change in feces color after the addition of .5% chromic oxide to the diet. The high fiber diet had a faster (P<.01) RP, which was associated with depressions (P<.001) in the digestibility of dry matter (DM), energy (E), cell contents, neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose (HC), cellulose, permanganate lignin and ash. Virginiamycin supplementation slowed (P<.004) the RP of both low and high fiber diets, but improved (P<.05) the DM, E, NDF, ADF, HC and cellulose digestibility of the high fiber diet only. Fiber increased (P<.06) fecal N excretion, whereas virginiamycin supplementation decreased (P<.08) fecal N excretion. The addition of virginiamycin improved the absorption and retention of P, Ca, Mg, Cu, Fe, Zn and Mn when added to the high fiber diet, but had little or no effect when added to the low fiber diet even though absorption and retention values for most minerals were similar or slightly higher for the unsupplemented high fiber diet compared with the unsupplemented low fiber diet. The absorption of K and Na was slightly depressed, but retention was slightly improved, for pigs fed high fiber diets compared with pigs fed low fiber diets; virginiamycin had no effect. It is concluded that virginiamycin supplementation improved energy utilization and mineral absorption and retention of a high fiber diet, but had little effect on a low fiber diet.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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