45
Lactation performance in sows fed diets with graded levels of crystalline amino acids as substitute for crude protein at lysine requirement
The objective of this study was to test the hypothesis that lactation performance of sows fed diets containing 3 and 6% less CP will not differ, when supplemented with Crystalline AA (CAA) to meet standardized ileal digestible (SID) requirement, compared to a diet solely based on protein-bound AA. Multiparous purebred Yorkshire sows (n=48) were allocated to one of three dietary treatments: 17.16 (Control), 14.48% (MCP) and 11.82% CP (LCP), in a randomized complete block design. Diets were formulated to meet the SID Lys requirement. Control diet did not contain CAA and exceeded SID requirement in all other AA. The MCP and LCP diets contained the following CAA: Lys, Thr, Trp, and Val, in addition to Phe for LCP diet only. Voluntary feed intake was measured daily. Sow and piglet BW were measured on days 0, 3, 6, 9, 12, 15, 18 and 21, and milk samples collected on days 4 and 16. Data was analyzed as a randomized complete block design with parity, day, and diets as fixed classification effects, and sow as random effect. Compared to Control, voluntary feed intake (kg) of sows fed MCP and LCP did not differ (P = 0.373) and was 5.85, 5.64, 5.66 (± 0.1150) for Control, MCP, and LCP, respectively. Compared to Control, piglet ADG of sows fed MCP and LCP did not differ (P=0.757) and were (g/d) 263.5, 277.2, and 274.0 (±13.9, respectively). Compared to Control, milk urea- nitrogen (MUN) (mg/dL) decreased (P<0.001) for MCP and LCP, and was 8.57, 6.85 and, 2.94mg/dL (± 0.93), respectively. In conclusion, feeding reduced CP diets with CAA supplementation did not impact lactation performance and reduced MUN. These results are the first to suggest that aggressive CAA can be implemented in lactating sow diets to optimize nitrogen utilization.
Keywords: Lactation, Sow, Amino Acid