TY - JOUR
T1 - Effect of dietary supplemental vitamin A concentration on performance, carcass merit, serum metabolites, and lipogenic enzyme activity in yearling beef steers
AU - Bryant, T. C.
AU - Wagner, J. J.
AU - Tatum, J. D.
AU - Galyean, M. L.
AU - Anthony, R. V.
AU - Engle, T. E.
PY - 2010/4
Y1 - 2010/4
N2 - A randomized complete block design experiment with 360 single-source black yearling steers (average BW = 316.1 ± 9.1 kg) fed a 91% concentrate (steam-flaked corn base) diet was conducted to evalu-ate the effects of supplemental vitamin A (0, 1,103, 2,205, 4,410, or 8,820 IU/kg of dietary DM) on plasma and liver vitamin A and E concentrations, lipogenic en-zyme activity, marbling score, and performance of year-ling steers. Final BW (586, 580, 590, 585, and 584 kg for 0, 1,103, 2,205, 4,410, and 8,820 IU of supplemental vitamin A/kg of DM, respectively) did not differ (P = 0.39) among treatments. Feed efficiency, ADG, and daily DMI did not differ (P > 0.10) among treatments within each 28-d period or for the overall experiment. From d 57 to slaughter, average DMI (10.33, 10.28, 10.57, 9.75, and 10.22 kg/steer daily for 0, 1,103, 2,205, 4,410, and 8,820 IU of vitamin A/kg of DM, respectively) was less (P < 0.02) by steers receiving 4,410 IU of supplemental vitamin A/kg of dietary DM than for steers in the other treatments. Furthermore, DMI was greater (P = 0.06) for steers receiving 2,205 IU of supplemental vitamin A/kg of dietary DM than for steers receiving 8,820 IU of supplemental vitamin A/kg of DM. Marbling score, HCW, LM area, and 12th-rib fat thickness did not differ (P > 0.10) among treat-ments. Similarly, the percentage of carcasses grading ≥USDA Choice (62.6, 52.8, 64.0, 58.4, and 58.4% for 0, 1,103, 2,205, 4,410, and 8,820 IU of vitamin A/kg of DM, respectively), Select, or ≤Standard did not differ (P > 0.10) among treatments. Except for d 56 (P = 0.050; r = 0.18 for liver retinol), no correlations (P > 0.10) between marbling score and any plasma or liver tissue retinol or α-tocopherol concentrations or vitamin A intake were found, and no differences (P > 0.10) in lipogenic enzyme activity were detected among treat-ments. Taken together with previous and concurrent re-search, results of this experiment suggest that vitamin A supplementation at a concentration up to twice the NRC recommendation has little effect on performance, marbling, or lipogenic enzyme activity in adipose tis-sue samples in yearling feedlot steers, and that 2,205 IU of supplemental vitamin A/kg of DM (20,000 IU/ steer daily) or less is adequate to meet the vitamin A requirements of finishing beef cattle.
AB - A randomized complete block design experiment with 360 single-source black yearling steers (average BW = 316.1 ± 9.1 kg) fed a 91% concentrate (steam-flaked corn base) diet was conducted to evalu-ate the effects of supplemental vitamin A (0, 1,103, 2,205, 4,410, or 8,820 IU/kg of dietary DM) on plasma and liver vitamin A and E concentrations, lipogenic en-zyme activity, marbling score, and performance of year-ling steers. Final BW (586, 580, 590, 585, and 584 kg for 0, 1,103, 2,205, 4,410, and 8,820 IU of supplemental vitamin A/kg of DM, respectively) did not differ (P = 0.39) among treatments. Feed efficiency, ADG, and daily DMI did not differ (P > 0.10) among treatments within each 28-d period or for the overall experiment. From d 57 to slaughter, average DMI (10.33, 10.28, 10.57, 9.75, and 10.22 kg/steer daily for 0, 1,103, 2,205, 4,410, and 8,820 IU of vitamin A/kg of DM, respectively) was less (P < 0.02) by steers receiving 4,410 IU of supplemental vitamin A/kg of dietary DM than for steers in the other treatments. Furthermore, DMI was greater (P = 0.06) for steers receiving 2,205 IU of supplemental vitamin A/kg of dietary DM than for steers receiving 8,820 IU of supplemental vitamin A/kg of DM. Marbling score, HCW, LM area, and 12th-rib fat thickness did not differ (P > 0.10) among treat-ments. Similarly, the percentage of carcasses grading ≥USDA Choice (62.6, 52.8, 64.0, 58.4, and 58.4% for 0, 1,103, 2,205, 4,410, and 8,820 IU of vitamin A/kg of DM, respectively), Select, or ≤Standard did not differ (P > 0.10) among treatments. Except for d 56 (P = 0.050; r = 0.18 for liver retinol), no correlations (P > 0.10) between marbling score and any plasma or liver tissue retinol or α-tocopherol concentrations or vitamin A intake were found, and no differences (P > 0.10) in lipogenic enzyme activity were detected among treat-ments. Taken together with previous and concurrent re-search, results of this experiment suggest that vitamin A supplementation at a concentration up to twice the NRC recommendation has little effect on performance, marbling, or lipogenic enzyme activity in adipose tis-sue samples in yearling feedlot steers, and that 2,205 IU of supplemental vitamin A/kg of DM (20,000 IU/ steer daily) or less is adequate to meet the vitamin A requirements of finishing beef cattle.
KW - Beef cattle
KW - Carcass quality
KW - Lipogenesis
KW - Marbling
KW - Vitamin a
UR - http://www.scopus.com/inward/record.url?scp=77949693629&partnerID=8YFLogxK
U2 - 10.2527/jas.2009-2313
DO - 10.2527/jas.2009-2313
M3 - Article
C2 - 20023133
AN - SCOPUS:77949693629
SN - 0021-8812
VL - 88
SP - 1463
EP - 1478
JO - Journal of animal science
JF - Journal of animal science
IS - 4
ER -