AMINO-ACID TRANSFER THROUGH THE RUMEN EPI THELIUM IN SHEEP - LEUCINE AND LYSINE INTERACTIONS

Experiments were conducted on six head of sheep of the Slovak Merino b reed with average live weight of 40 kg. The sheep received 0.4 kg of i ndustrially 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-s erosa direction. Amino acids were dissolved in Thyrode' s solution wit h pH value 6.9 on the mucosa side and 7.4 on the serosa side. A consta nt temperature of 39-degrees-C was maintained during the experiment. T he epithelium area was 13.2 cm2 for either part of the experiment. Lys ine and leucine were incubated separately in the first part of experim ent. These concentrations were used: 5, 25, 50 and 75 mumol/l. The val ues of lysine and leucine readings are denoted as control lysine (lysi ne K) and control leucine (leucine K) in the result section. Lysine an d leucine were incubated simultaneously in the second part of experime nt Lys 5 mumol/l - Leu 5 mumol/l; Lys 5 mumol/l - Leu 15 mumoI/l; Lys 5 mumol/l - Leu 20 mumol/l; Lys 25 mumol/l - Leu 25 mumol/l; Lys 25 mu mol/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 ep ithelium as depending upon their concentrations. The shape of the curv es shows that the amount of amino acid transfer was increasing with th e growing concentration in incubation medium but up to a certain maxim um value while the amount of amino acid transfer did not increase any more although the concentrations of amino acids were rising. Fig. 3 sh ows transfer of lysine K and lysine P. Lysine K transfer was compared when lysine was the only amino acid in the incubation solution and lys ine P transfer when lysine and leucine were incubated simultaneously. Leucine significantly reduced lysine transfer at leucine concentration s 5, 15 and 20 mumol/l. Leucine can inhibit lysine transfer approximat ely by more than 50%, while inhibition is largest at concentrations of 5, 15 and 20 mumol/l.