| Popis: |
White Leghorn laying hens were fed practical diets containing 0, 5, 10, 15, 20, 25, or 30% yellow grease. The nitrogen-corrected metabolizable energy (ME) of yellow grease was estimated from apparent digestibility data and from ME’s of the diet determined experimentally. The ME’s of yellow grease were consistently higher when dietary ME data were used in the calculations than when lipid digestibility data were used (8380, 8770, 8567, 9050, 8408, and 8473 kcal/kg vs. 8360, 8344, 8278, 8456, 8212, and 8540 kcal/kg for diets containing 5, 10, 15, 20, 25, and 30% fat, respectively). A comparison also is presented of ME values for yellow grease obtained by conventional calculation or by use of regression analysis. Regardless of the method of calculation, the ME data indicated that supplemental yellow grease exerted an extrametabolic effect on dietary ME, although the magnitude of this effect varied with the mathematical approach used. |
