|Parr, T - UNIVERSITY OF ILLINOIS|
|Baker, D - UNIVERSITY OF ILLINOIS|
Submitted to: Illinois Swine Day Report
Publication Type: Research Notes
Publication Acceptance Date: November 1, 2003
Publication Date: November 1, 2003
Citation: Parr, T.M., Kerr, B.J., Baker, D.H. 2003. Isoleucine requirement for late-finishing (87 to 100 kg) pigs. Illinois Swine Day Report. p. 10-19. Interpretive Summary: Research conducted on the isoleucine requirement of pigs is extremely limited and was conducted over 25 years ago involving pigs with limited lean growth potential. Moreover, validation of isoleucine-deficient assay diets were seldom carried out, and often the experimental pigs were limit fed rather than full fed. Lastly, energy and protein levels of assay diets were different from the levels used in practice today and the isoleucine digestibility of the basal diets was not known. Thus, recent estimates of the isoleucine requirement of pigs (National Research Council Subcommittee on Swine Nutrition, 1998) were based on (calculated) factorial estimates rather than on empirical evidence. As environmental issues with nitrogen losses from swine operations becomes more pressing and as the availability of crystalline amino acids becomes more economically viable, understanding amino acid limitations in low crude protein diets and their desired concentration in feeding programs for optimal production and minimal nitrogen excretion, is paramount. Experimentation indicated that a corn-soybean meal-red blood cell diet was determined to be markedly deficient in isoleucine, but fully efficacious when fortified with surfeit isoleucine. The results from this research suggest a requirement estimate of 0.31% true digestible isoleucine for late-finishing pigs which is similar to that estimated by the 1998 National Research Council. Research results described in this report provides nutritionists at universities, feed companies, and swine production units vital data on how to clearly define the isoleucine needs of finishing swine to properly formulate their diets to optimize growth performance and ultimately to minimize nitrogen excretion.