Microencapsulation of L-Lysine for Improving the Balance of Amino Acids in Ruminants

ved October 28, 19.9.9 and aaepted Novenwer 5, 1999) L-Lysine was microencapsulated by the spray-dry met.hod for improvement of the balance of alllino acids in ruminants.The rumen-bypm;s lllicrocCljJsulc was jJrqmn~d using zein or shellac as an outer coat.ingagcnt [or protection against microbial degradation in the rumen.L-Lysine was generated with a .yield of ,')0% in casp of zein microcapsules and :3:3% in shellac microcapsules and a mean particle di,uneter of 20-30 pItt.Bot.h rumen •b:ypass microcapsules had high stability in a neutral solution that mimicked ruminal pH (pI-I 6.f:i), suggesting t.hat L-l:ysinc should not be susceptible lo damage by rLiminal microorganisms.Moreover, tilt' efficiency of release of these microcapsules was 70% in the zein microcapsule and 85% in the shellac microcapsule within only 30 min in the abomasal environment (pH :U)) In addition, about 90% of encapsulated L-lysine \'las released from zein microcapsules in pepsin solution.lNTIWDCCTION Postruminal supplements of amino acids and proteins may increase growth and productivity in ruminants.An increased emphasis on higher production per animal and improvement in efficiency of production has stimulated the use of high energy rations in fceding ruminants.However. the expected theoretical efficiencies of feed conversion often have not been achieved due to unknmvll factors 'ivhich limit nutrient utilization.Onc of the many factors affecting energy conversion efficiencies is the amino acid profile of the diet.Ruminants synthesize microbial protein in the rumen as the major protein source instead of consuming the protein.Thus, the value of a protein source in improving rwninant performance is determined by its ability to supply limited amino acids, such as methionine or S-containing amino acids and lysine.to the small intestine and availability of nitrogen for use by rwninal microorganisms.Actually, ruminal microorganisms can supply the amino acids for grovvth and production in ruminant.sfed a purified diet containing only nonprotein nitrogen as the nitrogen source, but the amino acid supply is inadequate in animals whose protein requirements are high, e. g., grm",ing calves or high :yiclding milk cows.An insufficient supply of high protein feed seems to reduce the milk protein content, especially when the cow has a deficiency in the essential amino acids that form milk protein.Some studies have shown that abomasal or intraperitoneal infusion of methionine improved the wool growth of sheep (Wright, 1971) and milk production of dairy cows (Broderick et ai., 1974).