Thesis
Neonatal injection of vitamin A promotes intramuscular adipogenesis in Angus beef cattle
Washington State University
Master of Science (MS), Washington State University
2017
Handle:
https://hdl.handle.net/2376/101970
Abstract
Marbling, or intramuscular fat, is one of the most important factors in the palatability of beef. Previous studies have shown that vitamin A (VA) promotes the formation of new fat cells in skeletal muscle through an increase in the expression of Zinc finger protein (Zfp) 423, a key regulator of fat cell formation. We hypothesized that VA injection during commitment of fat cells in muscle would enhance intramuscular adipogenesis and marbling through the expression of Zfp423. Angus steer calves (n = 26), in a Completely Randomized Design, were randomly allotted to three treatment groups at birth. The first group (n = 9) received no supplemental VA, while the second (n = 7) and third group (n = 10) were given 150,000 IU of VA and 300,000 IU of VA at both birth and one month of age, respectively. At two months of age, blood serum and a biopsy of the Biceps femoris muscle were collected. After weaning, calves were fed a backgrounding diet until approximately 309-d of age before being transitioned to a high- concentrate feedlot diet until harvested at 429-d. Concentration of retinoic acid (pmol/mL) was highest (P < 0.05) in the low-level treatment group at two months of age. Expression of Zfp423 showed a similar pattern to retinoic acid, being significantly higher (P < 0.05) in the low-level treated cattle as well. Weaning weight and weight during the backgrounding phase were linearly increased (P < 0.05) by VA level. Intramuscular fat of steers at 309-d of age, measured by ultrasound, quadratically increased (P < 0.05) with VA level from 4.0 to 4.9 % ± 0.26. Similarly, carcass marbling score (small = 500, modest = 600) in the ribeye quadratically increased (584, 672 and 610 ± 20.20 for the 0 IU, 150,000 IU and 300,000 IU treatment groups, respectively). Carcass back fat thickness also quadratically increased (P < 0.05) with level of VA. Cattle that received VA had greater marbling, though further studies will need to evaluate an optimal amount as the low-level treatment group had greater fat development. Dietary VA enhanced intramuscular adipogenesis and marbling thereby improving meat quality.
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Details
- Title
- Neonatal injection of vitamin A promotes intramuscular adipogenesis in Angus beef cattle
- Creators
- Corrine Lynn Harris
- Contributors
- Mark Loge Nelson (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Animal Sciences, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525056301842
- Language
- English
- Resource Type
- Thesis