Three classical deletion assays were conducted to determine the limiting order of amino acids (AA) in a low-protein diet for 10-kg pigs. Deletion of lys depressed performance to a greater extent than deletion of any other AA. Results indicated lys was first limiting and Trp, Thr, Met, and Val were second co-limiting. In the second project, 12 suckling pigs (10 d of age) were fitted with modified simple T-cannulae at the terminal ileum. Cannulae were exteriorized through the ribs to increase stability and longevity of use. Pigs were returned to their original sows and resumed normal behavior within 2 d of surgery. Pigs were subsequently used in digestion studies until 20 kg BW. In the third project, six experiments were conducted to determine the true ileal digestible Val requirement of 5 to 20 kg pigs. Two Val-deficient diets were developed and validated. Valine digestibility was 82% (5 to 10 kg) and 86% (10 to 20 kg). Broken-line analysis of dose-response titration studies indicated that weaned pigs (5 to 10 kg) required 0.86% digestible Val or 2.50 g/Mcal ME (NRC = 2.48). Young pigs (10 to 20 kg) required 0.775% digestible Val or 2.22 g/Mcal ME (NRC = 2.11). In the fourth project, the true ileal digestibility of AA in sow's milk was determined. In 14 kg of milk, Co-EDTA and YbC13 were added and the milk was fed to 17-d-old pigs fitted with T-cannulae. Average nitrogen and AA digestibilities were 88% and 92(range = 84--100)%, respectively. Whey AA were less digestible than casein AA. Ratios of digestible AA to lys were at or above accepted values for young pigs, although Thr appeared to be marginal.
Agriculture, Animal Culture and Nutrition
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign