PSII-5 Corn-expressed phytase improved the growth performance, nutrients digestibility and bone mineral density of nursery pigs fed with low protein, calcium and phosphorous diets

Feeding pigs with moderately reduced crude protein (CP), calcium (Ca) and phosphorous (P) diets may be an effective strategy to decrease the nutrients excretion; however, this practice can negatively impact the growth performance. Thus, there is an urgent need to improve the utilization of nitrogen, Ca and P in pigs. The objective was to assess the effect of phytase (GraINzyme®) on growth performance, nutrient digestibility, body composition, and serum amino acid profile in pigs fed with low-CP, -Ca and -P diets. Following 2-week acclimation period, forty-eight weaned barrows weighing ~ 10 kg were subjected to one of following groups (n = 8/group) for 4 weeks: A) standard-protein (~24% CP), B) low-protein (~13% CP), C) low-protein+2000 FTU/kg phytase, D) low-protein+4000 FTU/kg phytase, E) low-protein, -Ca and -P+2000 FTU/kg phytase and F) low-protein, -Ca and -P+4000 FTU/kg. The data were analyzed by univariate GLM with Tukey’s post-hoc test (SPSS®). Feed intake and body weight were measured daily and weekly, respectively. At week 4, feed, fecal and blood samples were collected and pigs were scanned using dual-energy X-ray absorptiometry. Pigs fed with diets C and F had higher average daily gain than those fed with diet B (P < 0.05). The apparent fecal digestibility of Ca and P and bone mineral density was higher for diets D and F than diet B (P < 0.05). Pigs fed diet C and F had a higher fat mass than those fed with diet B (P < 0.05). Serum lysine, methionine and threonine of pigs fed with diets B-F were greater than those received diet A (P < 0.05). In conclusion, our data provide evidence that phytase, in particular at 4000FTU/kg, improved the growth performance, digestibility of Ca and P and bone mineral density in pigs fed with moderately low protein diets with reduced Ca and P content.