The effect of superdosing phytase with or without the addition of live yeast in diets void of spray dried plasma in pigs from weaning to 21 days post-weaning

Abstract Text: A 21d starter feed trial was designed to determine if adding 2000 FTU/kg of phytase (Quantum Blue) to a simple diet (SD; no plasma/high soybean meal (SBM)) with or without a live yeast (Vistacell) would improve pig performance and be comparable to pigs fed a complex diet (CD; plasma/low SBM). Weaned pigs (n=360; 6.0 ± 0.01 kg) were assigned to one of four dietary treatments with 9 replicate pens per treatment and 10 pigs per pen (mixed sex). Treatments were as follows; CD) 6% spray dried plasma (SDP; 15% SBM in phase 1 (P1) and 3% SDP (20% SBM in phase 2 (P2), SD) negative control (NC) with plasma replaced by SBM (P1: 25%; P2: 30%), SD1) NC + 2000 FTU/kg phytase, SD2) NC + 2000 FTU/kg phytase and 1 kg/t of live yeast. All pigs were fed a two phase feed program (P1 = 1-7d and P2 = 7-21d) post-weaning with each diet in each phase formulated to be iso-nutrient including available P (0.50% and 0.45% for P1 and P2, respectively) regardless of the inclusion of phytase. Data were analyzed using the Fit Model platform in JMP v 11.0. In P1, pigs fed the CD had higher ADG (P<0.05) and ADFI (P<0.05) and better FCR (P<0.05) than all other treatments. There were no other performance differences between treatments in P1.  In P2, pigs fed the SD1 and SD2 had higher ADG (P<0.05) and ADFI (P<0.05) and better FCR (P<0.05) compared to pigs fed the SD, while there was no significant difference between CD and SD. Overall (21d) there was no significant differences in ADG between CD, SD1 and SD2 and all three treatments were significantly (P<0.05) better than the SD. The use of SD negatively impacted FCR when compared to the CD diet (1.21 v 1.14; P<0.05), however the addition of high phytase (SD1) improved the FCR (P < 0.05) of the SD to that level of the CD fed pigs. The combination of live yeast and superdosing phytase (SD2) improved (P< 0.05) FCR of the SD to a level that was better (1.07; SD2 v 1.14; CD; P<0.05) than the CD fed pigs. In conclusion, SDP in starter diets may be replaced with diets containing higher levels of SBM without negatively impacting overall growth performance or efficiency, when dietary phytase is added at 2000 FTU/kg. Further FCR benefits can be achieved by the addition of live yeast with superdosing phytase.

Keywords: Starter, Phytase, Superdose