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Interactive effects of gestational heat stress, Paylean and lysine improve carcass and pork quality
In utero heat stress are known to alter postnatal growth performance, however little is known about its effects on carcass and pork quality. Therefore the objective was to determine the effects of in utero heat stress, excess lysine and Paylean on carcass and pork qualities of barrows. At 25 kg, barrows of control (TN; n=40) or heat stressed (HS; n=40) dams were individually housed and fed a corn soybean meal diet. At this time, barrows were equally and randomly assigned to receive a diet that met (100%; n=20) or exceeded (110%; n=20) NRC lysine requirements. In the last 30 days of finishing, barrows were again equally and randomly assigned to a diet containing 0 (CTL; n=10) or 7.4 ppm Paylean (PAY; n=10). Diets were fed until 121 kg of weight was attained. Carcass quality measures were recorded and a chop was used to determine pork quality measures. PAY increased HCW (100.24 ± 1.19 vs 99.36 ± 1.18 kg, P=0.02); LEA (54.89 ± 1.05 vs 48.85 ± 1.04 cm2, P<0.01); pH (5.62 ± 0.02 vs 5.56 ± 0.01, P=0.01); LEAN (53.82 ± 0.48 vs 53.56 ± 0.49 %, P=0.01); SF (4.73 ± 0.16 vs 3.94 ± 0.16 kg, P<0.01); and reduced b* (8.15 ± 0.19 vs 8.66 ± 0.18, P=0.05). HS barrows tended to have increased LEA (53.07 ± 1.06 vs 50.66 ± 1.04 cm2, P=0.10) and lighter subjective color scores (2.10 ± 0.09 vs 2.35 ± 0.09, P=0.06). PAY 110% barrows had reduced 10th rib back fat (P=0.04) compared to CTL 110% barrows (20.16 ± 1.26 vs 23.94 ± 1.23). 110% PAY barrows had greater LEAN compared to 100% CTL, 110% CTL, and 100% PAY barrows (54.61 ± 0.71 vs 52.16 ± 0.69, 51.48 ±0.69, and 52.51 ± 0.69 %, P<0.05). Pork chops from HS 100% barrows had less (P=0.02) cook loss than chops from TN 100% barrows (21.64 ± 0.94 vs 24.85 ± 0.94 %). HS 100 PAY barrows were firmer (P=0.05) than HS 110 PAY barrows (2.50 ± 0.22 vs 1.89 ± 0.23). Heat stress during gestation, Paylean and lysine have little impact on quality measures alone. However, the interactive effects of the treatments improved quality, reducing 10th rib back fat, increasing LEAN and firmness and reducing cook loss of pork chops.
Keywords:
Heat stress, carcass quality, pork quality, ractopamine