We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Effects of ruminal protein degradability and frequency of supplementation on nitrogen retention, apparent digestibility, and nutrient flux across visceral tissues in lambs fed low-quality forage.
- Authors
Atkinson, R. L.; Toone, C. D.; Robinson, T. J.; Harmon, D. L.; Ludden, P. A.
- Abstract
Two experiments were conducted to determine the effect of ruminal protein degradability and supplementation frequency on intake, apparent digestibility, N retention, and nutrient flux across visceral tissues of lambs fed a low-quality forage diet. In both experiments, wethers were fed a basal diet of mature crested wheatgrass hay (4.2% CP) for ad libitum consumption plus 1 of 4 supplements: 1) a high RDP supplement provided daily (RDP-D), 2) the high RDP supplement provided on alternate days (RDP-A), 3) a high RUP provided on alternate days (RUP-A), or 4) a 50:50 mixture of the RDP and RUP supplements provided on alternate days. In Exp. 1, 12 lambs (29.9 ± 2.7 kg initial BW) were used. Forage OM, NDF, and ADF intake were not affected by treatment. Total tract digestibilities (OM, NDF, ADF, and N) were unaffected (P ⩾ 0.15) by treatment. Neither protein degradability nor supplementation frequency had an effect (P ⩾ 0.52) on N retention. In Exp. 2, 15 lambs (34 ± 4 kg initial BW) fitted with indwelling catheters in a hepatic vein, the hepatic portal vein, a mesenteric vein, and a mesenteric artery were used. Release of ammonia N by the portal-drained viscera (PDV) was reduced (P = 0.004) in alternate-day-supplemented lambs compared with RDP-D. Consequently, hepatic uptake of ammonia N was least (P = 0.003) in all alternate-day lambs. Alpha-amino nitrogen (AAN) release by the PDV and hepatic uptake of AAN were not affected by treatment or supplementation frequency. Additionally, hepatic output and PDV uptake of urea N were not affected by treatment. Hepatic N uptake (ammonia N + AAN) accounted for urea synthesized by the liver in all treatments; however, hepatic urea synthesis was approximately 4.5-fold less for RUP-A lambs. This suggests that the provision of AA as RUP may provide a delay in ureagenesis, thus altering the timing of N recycling.
- Subjects
RUMINANT feeding &; feeds; RUMEN fermentation; PRESERVATION of organs, tissues, etc.; ORGANS (Anatomy); NITROGEN compounds; DRUG delivery devices; BILIARY tract; METABOLISM; URINALYSIS; NITROGEN excretion
- Publication
Journal of Animal Science, 2010, Vol 88, Issue 2, p727
- ISSN
0021-8812
- Publication type
Article
- DOI
10.2527/jas.2009-2246