Efficacy of phytase and/or chromium tripicolinate supplementation on dry matter and nitrogen digestibility and blood metabolites in grower pigs.

Phytase supplementation is widely used throughout the world for enhancing nutrient use efficiencies in pigs, while added chromium has been shown to help stabilize glucose metabolism by enhancing insulin sensitivity. Therefore, the objectives of this metabolism study were to examine the potential synergies of these additives to see if nutrient digestibilities and/or blood metabolites could be improved in grower pigs. A total of 12 Genesus terminal genetics grower pigs (20.7 kg) were allotted randomly in a crossover experiment with 4 periods and 4 dietary treatments based on a 2 × 2 factorial design via 2 groups. This provided 12 replicates per dietary treatment. Treatment (Trt) 1 consisted of a control diet without phytase while Trt 2 had decreased levels of soybean meal, calcium (Ca) and phosphorus (P) with added phytase (1,500 phytase units (FYT)/kg, HiPhorius; dsm-firmenich, Plainsboro, NJ). The nutrient release values for amino acids, calcium and phosphorus were via standard recommendations from dsm-firmenich for the phytase. Treatment 3 consisted of the control diet without phytase with 200 parts per billion (ppb) of added chromium from chromium tripicolinate (Chromax, Kent Nutrition Group, Inc., Muscatine, IA) while Trt 4 consisted of the diets with decreased levels of soybean meal, Ca and P with added HiPhorius (1,500 FYT/kg) and Chromax (200 ppb). With 6 metabolism crates available, 4, 1-wk-long periods were utilized to evaluate each of the 4 treatments with each pig with 2 groups evaluated and pooled for data analysis. The pigs were allowed a 4-d acclimation period followed by a 3-d collection period with the experimental diets fed at 4% body weight each day. Water was administered to each pig at 2.5 times the amount of feed fed each day. On the last day of the collection period, blood samples were collected before the meal (fasting) and then 2 h after the meal (postprandial). There were no significant differences among treatments for both fasting and postprandial glucose and insulin levels. Added phytase resulted in a reduction (P < 0.05) in fasting blood urea nitrogen (N). Nitrogen digestibility and retention and dry matter (DM) digestibility were all improved (P < 0.01) with pigs fed supplemental phytase. Supplemental chromium was without effect on any of the N and DM digestibility measurements. These data suggest that supplemental phytase has positive effects on improving N and DM digestibilities.