|Dailey, Jeffery - Jeff|
|Carroll, Jeffery - Jeff Carroll|
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/1/2011
Publication Date: 6/22/2011
Citation: Cappellozza, B.I., Cooke, R.F., Trevisanuto, C., Tabacow, V.D., Bohnert, D.W., Dailey, J.W., Carroll, J.A. 2011. Camelina meal supplementation to beef cattle: III. Effects on acute-phase and thyroid responses. Proceedings, Journal of Animal Science. Proceedings, Western Section, American Society of Animal Science. 62:261-263. Interpretive Summary: Camelina meal, a byproduct from the mechanical processing of the camelina seeds for oil extraction, may contain up to 20% oil with the majority of the fatty acid content as polyunsaturated fatty acids (PUFA). Scientists theorized that camelina meal can serve as a sustainable nutritional alternative to modulate the acute-phase response in cattle subjected to stress of management. Based on this rationale, a collaborative study was conducted by scientists from Oregon State University's Eastern Oregon Agricultural Research Center in Burns, OR, and the ARS' Livestock Issues Research Unit in Lubbock, TX, to evaluate the potential effects of supplementing beef cattle diets with camelina meal as a source of PUFAs on the acute phase response stimulated by transportation and subsequent performance. The specific objectives of this study were to evaluate the effects of camelina meal supplementation on concentrations of acute-phase proteins and thyroid hormones in beef steers following corticotropin-releasing hornone (CRH) and thyrotropin-releasing hormone (TRH) challenges, respectively. Results from this study indicated that camelina meal supplementation did not impair thyroid gland function following a TRH challenge, but alleviated the acute-phase protein response stimulated by CRH challenge in beef steers. These results will be of interest to scientists in academia, industry, and government agencies conducting research in the areas of stress regulation, the acute phase response in cattle, and cattle performance and well-being.
Technical Abstract: Fourteen halter-trained Angus steers were ranked by initial BW (average 191 ± 2.1 kg), and assigned (d 0) to receive supplements containing (as-fed basis): 1) 84% corn, 14% soybean meal, and 2% mineral mix (CO); and 2) 70% corn, 28% camelina meal, and 2% mineral mix (CAM). Treatments were offered individually, at a daily rate of 1.65 and 1.52 kg of DM/steer for CO and CAM, respectively. Alfalfa-grass hay was offered ad libitum during the study (d 0 to 36). On d 24, steers were fitted with a jugular catheter and were infused (i.v.) on d 25 with 0.5 micrograms of bovine corticotropin-releasing hormone (CRH)/kg of BW. Blood samples were collected hourly from –2 to 0 h and 4 to 8 h, and every 30 min from 0 to 4 h relative to treatment infusion (0 h). Blood samples were also collected via jugular venipuncture every 6 h from 12 to 72 h, and every 24 h from 96 to 168 h. All samples were analyzed for plasma concentrations of cortisol, ceruloplasmin, and haptoglobin. No treatment effects were detected (P = 0.28) for cortisol concentrations, which peaked for both treatments at 0.5 h relative to CRH infusion (time effect; P < 0.01). Ceruloplasmin concentrations were greater for CO vs. CAM steers at 6, 18, 42, 120, 144, and 168 h relative to CRH infusion (treatment × time interaction, P < 0.01). Mean haptoglobin concentrations tended to be greater (P = 0.10) for CO vs. CAM steers (1.73 vs. 1.54 absorbance @ 450 nm × 100, respectively). On d 34, steers were again fitted with a jugular catheter and were infused (i.v.) on d 35 with 0.33 micrograms of bovine thyrotropin-releasing hormone (TRH)/kg of BW. Blood samples were collected hourly from –2 to 0 h and 4 to 8 h, every 30 min from 0 to 4 h, and every 4 h from 8 to 24 h relative to treatment infusion (h 0) for determination of serum T3 and T4. No treatment effects were detected for T3 (P = 0.58) and T4 (P = 0.54) concentrations, which peaked, respectively, at 3 and 5 h relative to TRH infusion in both treatments. In conclusion, camelina meal supplementation did not affect thyroid gland function following a TRH challenge, but alleviated the acute-phase protein response following a CRH challenge in beef steers.