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ARS Home » Pacific West Area » Dubois, Idaho » Range Sheep Production Efficiency Research » Research » Publications at this Location » Publication #158684


item Reed, Meredith
item Obeidat, Belal
item Strickland, James
item Krehbiel, Clinton
item Taylor, Joshua - Bret
item Loest, Clint
item Bell, Greg

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2003
Publication Date: 7/1/2003
Citation: Reed, M.M., Obeidat, B.S., Strickland, J.R., Krehbiel, C.R., Taylor, J.B., Loest, C.A., Bell, G.S. Effects of swainsonine on digestion in wethers consuming locoweed. Journal of Animal Science. 2003. v 81 (Suppl.1): Abstract p. 251.

Interpretive Summary:

Technical Abstract: A trial was conducted to study the effects of swainsonine on digestion. Mixed breed wethers were assigned to one of three treatments. Wethers received blue grama hay plus 1.6 mg swainsonine/kg BW (n = 5), 0.2 mg swainsonine/kg BW (n = 6), or no swainsonine (control; n=6). Swainsonine was administered by feeding locoweed (428 ug swainsonine/g dry matter). Blood was collected via jugular venipuncture at 12 h intervals on d 1, 8, 11, 14, and 18 to determine serum swainsonine, alkaline phosphatase, and aspartate-amino transferase activity. Rises (P < 0.05) in alkaline phosphatase and aspartate amino transferase activity indicated subclinical toxicity in treated wethers. Rumen samples were collected from 0 to 48 h in 8 h intervals to determine effects on ammonia and volatile fatty acid concentrations. Ammonia concentrations were lower (P < 0.05) for controls than treated animals at 8 h and higher (P < 0.05) at 24 and 48 h. Volatile fatty acid (VFA) concentrations essentially were not affected (P > 0.08) showing no time by treatment effect for all VFA except valerate. Valerate concentrations increased (P < 0.05) at h 8 in 1.6 mg swainsonine/kg BW wethers. In situ samples contained 5 g of treatment diets and placed into the rumen representing h 0, 3, 6, 9, 12, 24, and 48. Treatments were 0.2 mg swainsonine/kg BW (n = 4), 1.6 mg swainsonine/kg BW (subacute exposure; n = 4), 0 at 1.6 mg swainsonine/kg BW (acute exposure; n = 3), or no swainsonine (n = 3). Dry matter digestion was greatest (P < 0.05) for both the 1.6 mg swainsonine/kg BW and 0 at 1.6 mg swainsonine/kg BW treatments. Organic matter, NDF, ADF, and CP showed no effects (P > 0.1) on digestion. Duodenal and fecal flow rates were apparently unaffected (P > 0.09). Enzyme and swainsonine activity levels in serum indicated subclinical toxicity. However, lack of consistent results in digestive parameters indicates limited effects of swainsonine on digestive processes.