Determining the Optimal Isoleucine:Lysine Ratio for the 25 to 50 LB Pig

Kansas State University Swine Research. A 21-day growth trial was conducted to determine the isoleucine:lysine ratio necessary to optimize growth p erformance of the 25 to 50 lb nursery pig reared in a segregated earlyweaning (SEW) system. T en experimental diets, including two levels of lysine (.75% and 1.10% digestible lysine) and five apparent digestible isoleucine:lysine ratios (45, 50, 55, 60, and 65%), were used in a 2 5 factorial arrangement. Growth performance was improved by feeding 1.10% rather than .75% digestible lysine. Also, results indicated that the apparent digestible isoleucine requirement for the SEW-reared, 25 to 50 lb pig is approximately 50% of digestible lysine.