EFFECT OF THE SACCHARINA LEVEL IN THE FEED ON THE RUMINAL MICROBIAL-POPULATION AND ITS ACTIVITY IN DAIRY-COWS

Latin square design was used for studying the of the Saccharina level in the feed on the ruminal microbial population and its activity in co ws consuming fresh forage as the basal diet. Treatments were: A) forag e + 4 kg feed with 50% Saccharina; B) forage + 4 kg feed with 70% Sacc harina; C) forage + 4 kg feed with 90% Saccharina and D) forage + 4 kg of commercial feed. Rumen liquor samplings were carried out at 0, 2, 4 and 6 hr after concentrate supply. The population of ruminal cellulo lytic bacteria was of 13.16; 13.39; 953 and 5.00 c.f.u. x 10(-7)/ml fo r A, B, C and D, respectively. The specific activity of the complex of Cellulase enzymes was increased with the three inclusion levels of Sa ccharina. The populations of total viable amylolytic, proteolytic and saccharolytic bacteria did not differ between treatments. Total volati le fatty acids, ammonia and lactic acid concentrations were maintained within the normal ranges in the rumen of cows fed pastures and feed s upplement and there were no differences between treatments. Yield of m icrobial cells/mol of fermented ATP (YATP) was similar between treatme nts. It is concluded that it is possible to substitute 50 or 70% of th e raw materials of the feed for dairy cows due to the fact that it imp roves the microbiological composition of the rumen