Effects of phytase with or without multi-carbohydrase supplementation on growth performance, nutrient digestibility, and bone traits in nursery pigs

Abstract

The aim was to determine the effects of supplementing increasing doses of phytase (PHY) alone or in combination with a multi-carbohydrase (MC) blend to a P-deficient diet of nursery pigs on growth performance, nutrient digestibility, and metacarpal bone characteristics. A total of 192 weaned pigs (7.7 ± 0.05 kg BW) were allotted to 1 of 8 dietary treatments each with 8 replicates in a randomised complete block experimental design. Pigs were fed P-deficient diets in a 4 × 2 factorial arrangement based on phytase level (0, 250, 500,1000 FTU/kg) and MC level (0 and 0.1g/kg). Fecal samples (d 18, 19, and 20) and metacarpal bones (d 21) were collected to determine apparent total tract digestibility (ATTD) of energy and nutrients and bone mineralization, respectively. Data were analyzed using the MIXED procedure of SAS utilizing orthogonal polynomial contrast statements with a pen as the experimental unit for growth performance and digestibility and pig as experimental unit for bone traits. By d 14, PHY with MC interactive effects significantly increase (P < 0.05) gain to feed ratio (G:F) whereas by d 21, increasing doses of PHY with or without MC addition linearly and quadratically (P < 0.05) increased average daily gain (ADG). Overall, PHY supplementation alone or in combination with MC quadratically increased (P < 0.05) ADG. However, there was an interaction (P < 0.05) whereby PHY and MC in combination acted synergistically to increase the ATTD of ash. Phytase had linear (P < 0.05) and quadratic (P < 0.05) effects by increasing fat-free dry weight, ash content and percentage, and metacarpal bone P content. In conclusion, MC alone did not exert much beneficial effect while increasing levels of PHY alone and when combined with MC quadratically improved growth performance, ATTD of ash and P, and bone traits of pigs fed P-deficient diets.