Diets rich in starch increase the posthepatic availability of amino acids in dairy cows fed diets at low and normal protein levels.

摘要: Abstract Five mid-lactation multicatheterized Jersey cows were used in a 4×4 Latin square design to investigate whether the increase milk N yield associated with diets rich starch versus fiber could originate from changes splanchnic AA metabolism and if these depended upon dietary crude protein (CP) content. Four isoenergetic formulated provide 2 different carbohydrate compositions [diets (350g of 310g neutral detergent fiber/kg dry matter) (45g 460g matter)] crossed by CP contents (12.0 vs. 16.5% CP). At end each treatment period, 6 hourly blood samples collected portal hepatic veins as well mesenteric artery determine net nutrient fluxes across portal-drained viscera (PDV), liver, total tissues. Dry matter calculated energy intake absorbed similar treatments. However, appearance (NPA) acetate, volatile fatty acids, β-hydroxybutyrate higher starch, whereas that oxygen, glucose, butyrate, insulin lower. Concomitant changes, percentage recovered (TAA) vein was lower for (42.3 51.4%, respectively), without, however, any difference observed NPA main fuels PDV (Glu, Gln, Asp). Despite TAA diets, no differences flux TAA, essential nonessential observed, resulting (+22%) release and, hence, greater (+7%) yield. The fractional removal none individual affected changed except Gly Lys, which latter. After correcting uptake tended be diets. transfer feed is not consequence direct sparing effect glucogenic but rather result requirements along microbial flow duodenum. A better use peripheral tissues also hypothesized more studies are warranted clarify this issue.