0
The hypothesis was that dietary crude glycerol would influence quality of pork and that duration of glycerol feeding may alter this response. Therefore, the objectives of this study were to determine the effects of long-term and short-term feeding of crude glycerol on growth performance, carcass characteristics, and muscle and fat quality of grow-finish pigs. Crossbred pigs (n = 216; BW = 31.3 ± 1.8 kg) were blocked by initial BW, and pens within blocks were assigned randomly to 1 of 3 dietary treatments (24 pens; 9 pigs/pen). Dietary treatments were control, a corn-soybean meal-based diet (CON); long-term, CON + 8% glycerol fed throughout the experiment (LT); and short-term, pigs fed CON for the first 6 wk followed by CON + 8% glycerol fed during the last 8 wk of the experiment (ShT).
Pigs fed LT had greater (P < 0.05) ADG, whereas pigs fed ShT tended (P < 0.10) to grow faster than CON. Pigs assigned to LT had greater (P < 0.05) average daily feed intake (ADFI) compared with CON, whereas ShT-fed pigs had similar ADFI to CON. Gain:feed tended (P < 0.10) to be greater for CON- and ShT-fed pigs compared with LT-fed pigs. Hot carcass weight was greater (P < 0.05) for LT-fed pigs compared with CON, whereas ShT-fed pigs had HCW similar to both LT- and CON-fed pigs. Dressing percentage of CON-fed pigs was similar to both LT- and ShT-fed pigs, but LT-fed pigs tended to have greater (P = 0.06) dressing percentage than ShT-fed pigs. Tenth-rib backfat (P = 0.26) and LM area (P = 0.17) were not affected by dietary treatment. There was a trend (P < 0.10) for LT-fed pigs to have a smaller fat-free lean percentage than CON-fed pigs. Short-term glycerol feeding increased (P < 0.05) belly firmness compared with CON and had similar belly firmness compared with LT-fed pigs. Dietary treatment had no effect (P > 0.60) on pork quality of loins based on taste panel assessments.
Feeding pigs 8% crude glycerol throughout the grow-finish period resulted in a 3% improvement in growth rate and a 2% depression in BW gain efficiency compared with CON diets. Grow-finish pigs fed diets containing 8% crude glycerol during the last 8 wk before slaughter achieved growth performance similar to pigs fed CON diets. Effects of crude glycerol on carcass traits seem to be limited to improvements in belly firmness with short-term feeding of glycerol.
SJ Schieck, GC Shurson, BJ Kerr and LJ Johnston, 2010. Journal of Animal Science, 88:3927-3935. http://dx.doi.org/10.2527/jas.2010-2858
