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Effect of vitamin A restriction on carcass characteristics and immune status of beef steers.
J Anim Sci 2008; 86(7):1609-16JA

Abstract

Sixty-eight Angus-based steers (224 +/- 7.6 kg of BW) were used to evaluate the effects of a prolonged dietary vitamin A restriction on marbling and immunocompetency. Steers were allotted randomly to 1 of 2 treatments: LOW (no supplemental vitamin A) and HIGH (diet supplemented with 2,200 IU of vitamin A/kg of DM). Diets contained 60% high-moisture corn, 20% roasted soybeans, 10% corn silage, and 10% of a protein supplement. Steers were penned and fed individually. For the first 141 d, steers were program-fed to achieve a gain of 1.1 kg/d. The last 75 d of the experiment, steers were offered feed for ad libitum intake. At slaughter, serum and liver samples were taken to determine their retinol content. To evaluate immunocompetency, 10 steers per treatment were selected randomly on d 141 and received an ovalbumen vaccine, and 21 d later, the steers were revaccinated. On d 182, blood samples were taken from the vaccinated steers to determine serum antibody titers by ELISA. Steers were slaughtered after 216 d on feed. Carcass characteristics were determined, and LM samples were taken for composition analysis. Subcutaneous fat samples were taken for fatty acid composition analysis. Performance (ADG, DMI, and G:F) was not affected by vitamin A restriction (all P > 0.10). Hot carcass weight, 12th-rib fat, and yield grade did not differ between LOW and HIGH steers (all P > 0.10). Marbling score (LOW = 574 vs. HIGH = 568, P = 0.79) and i.m. fat (LOW = 5.0 vs. HIGH = 4.7% ether-extractable fat, P = 0.57) were not increased by vitamin A restriction. Serum (LOW = 18.7 vs. HIGH = 35.7 mug/dL, P < 0.01) and liver (LOW = 6.3 vs. HIGH = 38.1 mug/g, P < 0.01) retinol levels were lower in LOW steers compared with HIGH steers at slaughter. Response to ovalbumin vaccination was not affected by vitamin A restriction (LOW = 13.1 vs. HIGH = 12.8 log(2) titers, P = 0.60). Slight changes in the fatty acid profile of s.c. fat of the steers were detected. A greater proportion of MUFA (LOW = 41.7 vs. HIGH = 39.9%, P = 0.03) and fewer SFA (LOW = 47.1 vs. 48.7, P = 0.03) were observed in vitamin A-restricted steers. This suggests that vitamin A restriction may affect the activity of desaturase enzyme (desaturase activity index, LOW = 46.9 vs. HIGH = 44.9, P = 0.01). Feeding a low vitamin A diet for 216 d to Angus-based steers did not affect performance, marbling score, or animal health and immunocompetency. Slight changes in the fatty acid profile of s.c. fat were observed, suggesting that vitamin A restriction may have affected desaturase enzyme activity.

Authors+Show Affiliations

Department of Animal Sciences, The Ohio State University, Wooster.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

18344289

Citation

Gorocica-Buenfil, M A., et al. "Effect of Vitamin a Restriction On Carcass Characteristics and Immune Status of Beef Steers." Journal of Animal Science, vol. 86, no. 7, 2008, pp. 1609-16.
Gorocica-Buenfil MA, Fluharty FL, Loerch SC. Effect of vitamin A restriction on carcass characteristics and immune status of beef steers. J Anim Sci. 2008;86(7):1609-16.
Gorocica-Buenfil, M. A., Fluharty, F. L., & Loerch, S. C. (2008). Effect of vitamin A restriction on carcass characteristics and immune status of beef steers. Journal of Animal Science, 86(7), pp. 1609-16. doi:10.2527/jas.2007-0241.
Gorocica-Buenfil MA, Fluharty FL, Loerch SC. Effect of Vitamin a Restriction On Carcass Characteristics and Immune Status of Beef Steers. J Anim Sci. 2008;86(7):1609-16. PubMed PMID: 18344289.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effect of vitamin A restriction on carcass characteristics and immune status of beef steers. AU - Gorocica-Buenfil,M A, AU - Fluharty,F L, AU - Loerch,S C, Y1 - 2008/03/14/ PY - 2008/3/18/pubmed PY - 2008/9/20/medline PY - 2008/3/18/entrez SP - 1609 EP - 16 JF - Journal of animal science JO - J. Anim. Sci. VL - 86 IS - 7 N2 - Sixty-eight Angus-based steers (224 +/- 7.6 kg of BW) were used to evaluate the effects of a prolonged dietary vitamin A restriction on marbling and immunocompetency. Steers were allotted randomly to 1 of 2 treatments: LOW (no supplemental vitamin A) and HIGH (diet supplemented with 2,200 IU of vitamin A/kg of DM). Diets contained 60% high-moisture corn, 20% roasted soybeans, 10% corn silage, and 10% of a protein supplement. Steers were penned and fed individually. For the first 141 d, steers were program-fed to achieve a gain of 1.1 kg/d. The last 75 d of the experiment, steers were offered feed for ad libitum intake. At slaughter, serum and liver samples were taken to determine their retinol content. To evaluate immunocompetency, 10 steers per treatment were selected randomly on d 141 and received an ovalbumen vaccine, and 21 d later, the steers were revaccinated. On d 182, blood samples were taken from the vaccinated steers to determine serum antibody titers by ELISA. Steers were slaughtered after 216 d on feed. Carcass characteristics were determined, and LM samples were taken for composition analysis. Subcutaneous fat samples were taken for fatty acid composition analysis. Performance (ADG, DMI, and G:F) was not affected by vitamin A restriction (all P > 0.10). Hot carcass weight, 12th-rib fat, and yield grade did not differ between LOW and HIGH steers (all P > 0.10). Marbling score (LOW = 574 vs. HIGH = 568, P = 0.79) and i.m. fat (LOW = 5.0 vs. HIGH = 4.7% ether-extractable fat, P = 0.57) were not increased by vitamin A restriction. Serum (LOW = 18.7 vs. HIGH = 35.7 mug/dL, P < 0.01) and liver (LOW = 6.3 vs. HIGH = 38.1 mug/g, P < 0.01) retinol levels were lower in LOW steers compared with HIGH steers at slaughter. Response to ovalbumin vaccination was not affected by vitamin A restriction (LOW = 13.1 vs. HIGH = 12.8 log(2) titers, P = 0.60). Slight changes in the fatty acid profile of s.c. fat of the steers were detected. A greater proportion of MUFA (LOW = 41.7 vs. HIGH = 39.9%, P = 0.03) and fewer SFA (LOW = 47.1 vs. 48.7, P = 0.03) were observed in vitamin A-restricted steers. This suggests that vitamin A restriction may affect the activity of desaturase enzyme (desaturase activity index, LOW = 46.9 vs. HIGH = 44.9, P = 0.01). Feeding a low vitamin A diet for 216 d to Angus-based steers did not affect performance, marbling score, or animal health and immunocompetency. Slight changes in the fatty acid profile of s.c. fat were observed, suggesting that vitamin A restriction may have affected desaturase enzyme activity. SN - 1525-3163 UR - https://www.unboundmedicine.com/medline/citation/18344289/Effect_of_vitamin_A_restriction_on_carcass_characteristics_and_immune_status_of_beef_steers_ L2 - https://academic.oup.com/jas/article-lookup/doi/10.2527/jas.2007-0241 DB - PRIME DP - Unbound Medicine ER -