219 - Effects of Feeding Low Protein Diets with Additional Supplementation of First Five Limiting AA on Performance and Diarrhea Incidence in Weaned Pigs

An experiment was conducted to evaluate the effect of feeding low crude protein (CP) diets and supplying 110% of the first 5 limiting AA on performance and diarrhea incidence in weaned pigs. One of 3 treatments were randomly assigned to 81 piglets (BW: 8.2 ± 1.2 kg ; 9 pens/treatment; 3 pigs/pen) during 2 phases (3 wk each): a high CP (HP; 21 and 18%), a low CP (LP; 18 and 15%), or a low CP at 110% Lys, Met, Trp, Thr, Val requirements (LPAA; 18 and 15%) diet for phase 1 and 2, respectively. Pigs had ad libitum access to feed and water. Data were analyzed using PROC MIXED of SAS. During phase 1, pigs fed HP had the greatest ADG (P < 0.05), but ADFI and G:F were not different among treatments. In phase 2, no effect of treatments was observed on growth performance. Overall, pigs fed LPAA had the lowest (P < 0.05) ADG and G:F, and feeding LP decreased (P < 0.05) G:F. The ADFI was not affected by the treatments. Only during wk 3, pigs fed LPAA increased (P < 0.05) and LP tended to increase (P < 0.10) frequency of diarrhea compared to HP. On d 21, no treatment effect was observed for ileal villi height, but LPAA reduced (P < 0.05) and LP tended to reduce (P < 0.10) crypt depth compared to HP. Diet analysis revealed that LP was deficient in Ile and non-essential AA (NEAA), and LPAA contained inadequate levels of Ile, Leu, His and NEAA, which explains why reduced pig performance was achieved with these 2 diets. In conclusion, low CP diets, even with additional supplementation of the first 5 limiting AA, if deficient in the next limiting AA, results in negative effects on performance and diarrhea incidence.