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Impact of increasing dietary energy concentration through graded levels of corn oil or choice white grease on carcass characteristics in pigs
When the cost per unit of energy is advantageous, dietary fat is included as a concentrated source of energy. Increasing the dietary energy concentration can increase efficiency and fat deposition in the live pig, which can alter carcass characteristics and quality. The objective was to investigate the effects on carcass characteristics across 2 dietary fat sources (FS) and 3 fat inclusion levels (FL) over 134 d. A total of 1,213 pigs (PIC 15 × PIC Camborough 42; PIC, Hendersonville, TN) with an initial BW of 32.0 ± 0.4 kg were randomly allotted to 1 of 6 treatments in a 2 × 3 factorial: corn oil (CO; IV = 123.2) versus choice white grease (CWG; IV = 66.8) and fat levels of 2, 4 or 6%. There were 10 pens per treatment. Pigs were harvested in 3 groups based on BW on d 105, 117, and 134 at Tyson Foods Inc (Storm Lake, IA). Data were analyzed using PROC MIXED with FS and FL as fixed effects, room as a random effect, and pen as the experimental unit. No FS × FL interactions were statistically significant for any measured carcass characteristic (P ≥ 0.330). Hot carcass weight was not affected by FS (CO = 105.0, CWG = 105.1 kg; P = 0.792) or FL (2% = 104.5, 4% = 105.4, 6% = 105.4kg; P = 0.157). Increasing FL tended to increase carcass yield (2% = 74.7, 4% = 75.1, 6% = 75.1%; P = 0.069), but carcass yield was not altered by FS (CO = 74.9, CWG = 75.0%; P = 0.276). Increasing FL had no effect on backfat depth (2% = 1.97, 4% = 2.00, 6% = 2.03 cm; P = 0.502), loin depth (2% = 7.19, 4% = 7.18, 6% = 7.15 cm; P = 0.712), or percent lean (2% = 55.5, 4% = 55.4, 6% = 55.3%; P = 0.478). Dietary FS had no impact on backfat depth (CO = 2.02, CWG = 1.97 cm; P = 0.320), loin depth (CO = 7.18, CWG = 7.17 cm; P = 0.840), or percent lean (CO = 55.3, CWG = 55.4%; P = 0.542). In conclusion, both CO and CWG can be employed in swine diets without effect to hot carcass weight, yield, or percent lean. Increasing FL may slightly increase carcass yield, but have no effect on hot carcass weight or percent lean.
Keywords:
corn oil, choice white grease, swine