Submitted to: Journal of Animal Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/22/2004
Publication Date: 8/1/2004
Citation: Kerr, B.J., Kidd, M.T., Cuaron, J.A., Bryant, K.L., Parr, T.M., Maxwell, C.V., Weaver, E. Development of an isoleucine deficient diet containing dried blood cells in starting pigs. Journal of Animal Science. 82:2397-2404. Interpretive Summary: There are only limited empirical estimates of the isoleucine requirement for starting pigs as estimated in the National Research Council Subcommittee on Swine Nutrition, 1998. Because environmental issues with nitrogen losses from swine operations has become more pressing and as the availability of crystalline amino acids become 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. Results from three experiments show that utilization of dried red blood cells in starting pig diets clearly creates an isoleucine deficient diet. In addition, the data also shows that supplementation of crystalline isoleucine alleviates these depressions in growth, feed intake and feed efficiency to a level similar to pigs fed standard diets. This data will be utilized in future studies to estimate exact isoleucine requirements and concentrations relative to dietary lysine in starting pigs in an effort to fine tune requirement estimates of the National Research Council Subcommittee on Swine Nutrition, 1998. Research results described in this report provides nutritionists at universities, feed companies, and swine production units vital data on empirical research methodology on how to clearly define the isoleucine needs of starting pigs swine to properly formulate their diets to optimize growth performance and ultimately to minimize nitrogen excretion.
Technical Abstract: Three experiments were conducted to develop a diet containing spray dried red cells (SDBC) that could be confirmed to be markedly deficient in Ile, yet efficacious when fortified with surfeit Ile. In Exp. 1, 120 pigs, initial BW of 9.3 kg, were used to evaluate 0, 2, 4, and 6% SDBC in a sorghum-based diet over a 16 day period. Supplementing up to 4% SDBC had no impact on ADG or gain:feed (GF) ratio (P > 0.10). Pigs fed the diet containing 6% SDBC had reduced ADG (P < 0.05) and GF ratio (P < 0.10) compared to pigs fed lower levels of SDBC. In Exp. 2, 720 pigs, initial BW 7.0 kg, were used to test a corn-based, Ile-deficient based diet using 2.5 or 5.0% SDBC over a 16 day period. Supplementing 2.5% SDBC, with or without crystalline Ile, had no impact on pig performance (P > 0.10). Utilization of 5.0% SDBC without crystalline Ile reduced ADFI (P < 0.10), ADG and G:F ratio (P < 0.05). Supplementation of crystalline Ile restored ADFI (P < 0.10), ADG and G:F ratio (P< 0.05) to a level not different than pigs fed the control diets (P > 0.10). In Exp. 3, 840 pigs, initial BW of 6.7 kg, were used to refine the Ile-deficient diet tested in Exp. 2 through incorporation of 5.0, 7.5, and 9.0% SDBC over a 16 day period. Supplementation of 5.0% SDBC without crystalline Ile reduced ADG and GF ratio (P < 0.05), both of which were improved by crystalline Ile supplementation (P < 0.05). Supplementation of 7.5% SDBC reduced ADFI, ADG and G:F ratio (P < 0.05) which were improved by addition of crystalline Ile (P < 0.05). Supplementation of 9.5% SDBC dramatically reduced ADFI, ADG and GF ratio (P < 0.05), which were improved by addition of crystalline Ile (P < 0.05), but not to the level achieved by pigs fed the control diet (P < 0.10). These data indicate that SDBC can be supplemented at relatively high levels to starter diets and provide an excellent ingredient from which to evaluate Ile requirements and Ile:Lys ratios in starting pigs.