The feed enzyme xylanase improves finish pig viability and carcass feed efficiency

Abstract Text: This paper presents a novel find that the feed enzyme xylanase (XYL) improves pig viability.  Xylanases break down cell wall arabinoxylans to shorter chain xylo-oligomers and these become a food source for beneficial gut microflora.  In poultry, an increase in this substrate coincided with a balance shift toward more beneficial microflora.  This is hypothesized to support intestinal barrier function and improved host health.  A total of 2124 PIC castrate and female pigs (11.7 ± 0.2 kg) were used in a growth assay to approx. 137.9 kg (±.5 kg).  Pigs were placed in a commercial research facility, blocked by gender and genotype, stratified by weight and allocated (34 pigs/pen, 0.70 m²/pig) to diets with 0, 0.075, 0.150 or 0.225 g Danisco Xylanase/kg feed.  Treatments were arranged as a 2 x 4 x 3 factorial (sex, diet, genotype) with pen being the experimental unit.  Diets were composed of corn, soybean meal, corn DDGS (15.0%), wheat midds (10%) and soy oil (1.0%). Nutrient levels met or exceeded the requirement (PIC 2008).  Early nursery diets were medicated, however diets were maintained medication free after 30 kg body weight.  Paylean^® (Elanco) was used at 5 and 10 mg/kg in the final two diets.  Pigs were classified as moderately high health based on PRRS and PEDv negative status. Mortality and removal rate, for medical treatment, from 12 kg to harvest was 4.16%.  Under these conditions, increasing XYL dose tended to reduce mortality (3.99, 3.51, 2.25, 2.39%, SEM=.98, linear P=.175).  Death loss for pigs that remained in test pens (excluded medical pens) averaged 3.39, 2.32, 1.90, 1.62%, SEM=.82, linear P=.126).  Carcass ADG and G:F ratio was computed as the difference between estimated initial carcass weight (0.74 x b.w.) and plant carcass weight.  Carcass ADG was not improved but carcass FCR improved as XYL increased (.286, .287, .291, .290, P=0.012, SEM=0.0015).  This occurred, despite no improvement in whole-body G:F ratio, because carcass yield tended to improve with dose: 73.9, 74.0, 74.1, 74.3 % (P=.160 linear).  When gain was expressed on a pen basis (viable pigs x gain), whole-body and carcass gain improved in a linear manner (P=.071, P=.047); the latter averaged 2892, 2926, 3104, 3035 kg/pen (SEM, 66.4).  This study is the first to show that the feed enzyme XYL improves pig viability and in a dose related manner; even under high health conditions and for progeny of three genotypes (line x trt, P>.50).  This outcome has implications for animal well-being and reduced enteric antibiotic use.

Keywords: growing pigs, enzyme, xylanase, viability