[Transfer of amino acids across the rumen epithelium in sheep: interaction between leucine and lysine].

Experiments were conducted on six head of sheep of the Slovak Merino breed with average live weight of 40 kg. The sheep received 0.4 kg of industrially produced molasses feed M and 1 kg of meadow hay once a day. The feed ration for a head of sheep per day contained: 1177.58 g dry matter, 89 g digestible crude protein (SNL), 0.554 starch units. The animals had free choice of water. Rumen epithelium with submucosa was used in the experiment. Amino acid transfer was measured in a mucosa-serosa direction. Amino acids were dissolved in Thyrode's solution with pH value 6.9 on the mucosa side and 7.4 on the serosa side. A constant temperature of 39 degrees C was maintained during the experiment. The epithelium area was 13.2 cm2 for either part of the experiment. Lysine and leucine were incubated separately in the first part of experiment. These concentrations were used: 5, 25, 50 and 75 mumol/l. The values of lysine and leucine readings are denoted as control lysine (lysine K) and control leucine (leucine K) in the result section. Lysine and leucine were incubated simultaneously in the second part of experiment: Lys 5 mumol/l-Leu 5 mumol/l; Lys 5 mumol/l--Leu 15 mumol/l; Lys 5 mumol/l--Leu 20 mumol/l; Lys 25 mumol/l--Leu 25 mumol/l; Lys 25 mumol/l--Leu 75 mumol/l. The values of lysine readings on the other part of experiment are denoted as experimental lysine (lysine P). Figs. 1 and 2 show transfer of control lysine and leucine through the rumen epithelium as depending upon their concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)