PSVII-34 Digestibility and growth performance of growing pigs, fed corn or wheat diets supplemented with xylanase

Abstract

Abstract Corn and wheat contribute variable amounts of arabinoxylans (AX) to swine rations. Xylanase hydrolyzes AX into smaller oligosaccharides, potentially improving nutrient digestibility or fermentation. This experiment was designed to determine the response of growing pigs to exogenous xylanase supplementation in either a corn or wheat based diet. Two hundred pigs (7.99±2.8kg), 5 pigs/pen, 40 pens in 2 blocks (n = 10) were assigned to one of four treatments for 140±7d. Treatments, arranged in a 2x2 factorial, included grain (corn/wheat based) and xylanase (±0.01%,16 000 BXU/kg) as main effects. Pigs were on a five-phase feeding program; diets were isonitrogenous and isoenergetic within each phase. Growth and feed intake were determined weekly. Fecal samples were collected in phases two, four, and five. Growth, feed intake and feed efficiency were unaffected by xylanase (P > 0.10). Except for phase one, pigs receiving corn had improved (P < 0.05) ADG and ADFI relative to wheat; while G:F was improved only in the second phase (P < 0.05). Gross energy digestibility was higher in corn (88.2%) than wheat (87.2%) diets in the nursery phase (P < 0.05). In the finisher phase, xylanase improved energy digestibility of wheat diets (grain*xylanase, P < 0.05). During the nursery phase, percent fecal acetic acid was decreased with xylanase in corn; but increased in wheat diets (grain*xylanase, P < 0.05). Conversely, fecal isobutyric, butyric and isovaleric acid were decreased with xylanase in wheat diets only (grain*xylanase, P < 0.05). In the grower phase, fecal acetic acid was higher (P < 0.05) in wheat than corn diets, while isovaleric, valeric and caproic acid were reduced (P < 0.05). In the finisher phase, fecal propionic acid was lower in wheat diets (P < 0.05). During the finisher phase of growth, xylanase improved energy digestibility of pigs receiving wheat based diets, however this effect was not observed when pigs received corn based diets.