Effects of microbial xylanase on digestibility of dry matter, organic matter, neutral detergent fiber, and energy and the concentrations of digestible and metabolizable energy in rice coproducts fed to weanling pigs1

Abstract

The objective of this experiment was to test the hypothesis that the apparent total tract digestibility (ATTD) of DM, OM, fiber, and GE by weanling pigs and the concentration of DE and ME in full-fat rice bran (FFRB), defatted rice bran (DFRB), brown rice, and broken rice is improved if microbial xylanase is added to the diet. Eighty pigs (13.6 ± 0.8 kg initial BW) were allotted to 10 diets with 8 replicate pigs per diet in a randomized complete block design with 2 blocks of 40 pigs. A basal diet based on corn and soybean meal and 4 diets containing corn, soybean meal, and each of the 4 rice coproducts were formulated. The rice coproducts and corn and soybean meal were the only sources of energy in the diets. Five additional diets that were similar to the initial 5 diets with the exception that they also contained 16,000 units of xylanase (Econase XT-25; AB Vista, Marlborough, UK) were also formulated. All diets also contained 1,500 units of microbial phytase (Quantum Blue 5G; AB Vista). The DE and ME and the ATTD of DM, OM, fiber, and GE in diets and ingredients were calculated using the direct method and the difference method, respectively. Results indicated that the concentrations of DE and ME (DM basis) in FFRB and DFRB increased ( < 0.05) if xylanase was used. Broken rice had a greater ( < 0.05) concentration of DE and ME than FFRB and DFRB if no xylanase was added to the diets, but if xylanase was used, no differences in ME among FFRB, brown rice, and broken rice were observed. The ATTD of DM was greater ( < 0.05) in ingredients with xylanase than in ingredients without xylanase and there was a tendency ( = 0.067) for the ATTD of OM to be greater if xylanase was used. The ATTD of NDF in FFRB was greater ( < 0.05) when xylanase was added than if no xylanase was used, whereas the ATTD of NDF in DFRB was not affected by the addition of xylanase. In conclusion, if no xylanase was used, broken rice and brown rice have greater concentrations of DE and ME than FFRB and DFRB, and these values were not increased by microbial xylanase. However, xylanase increased the concentration of DE and ME (DM basis) in FFRB and DFRB.

Gestating sows have greater digestibility of energy in full fat rice bran and defatted rice bran than growing gilts regardless of level of feed intake

“…The analyzed composition of corn and soybean meal used in this experiment are in agreement with reported values (Sauvant et al, 2004;NRC, 2012;Casas and Stein, 2016). However, the concentration of AEE in FFRB was greater than previous values, whereas the concentration of starch in FFRB and DFRB was slightly less than reported (Sauvant et al, 2004;NRC, 2012;Casas and Stein, 2016). Variation in the milling of rice or extraction of oil from the bran may be the reason for the variation in composition among sources of rice bran because different amounts of endosperm or oil may remain in the final product (Saunders, 1985).…”

“…The analyzed composition of corn and soybean meal used in this experiment are in agreement with reported values (Sauvant et al, 2004;NRC, 2012;Casas and Stein, 2016). However, the concentration of AEE in FFRB was greater than previous values, whereas the concentration of starch in FFRB and DFRB was slightly less than reported (Sauvant et al, 2004;NRC, 2012;Casas and Stein, 2016).…”

“…The ATTD of GE is between 72.8 and 80.0% in full fat rice bran (FFRB) and defatted rice bran (DFRB) fed to growing pigs (Robles and Ewan, 1982;Kaufmann et al, 2005;Casas and Stein, 2016). However, no values for the ATTD of GE or for DE and ME of FFRB and DFRB fed to gestating sows have been reported.…”

Processing of ingredients and diets and effects on nutritional value for pigs

“…In contrast, when xylanase was added to a corn-DDGS based diet, no improvement in energy digestibility was observed [23]. However, addition of xylanase to full fat or defatted rice bran resulted in a significant improvement in DE and ME of the ingredients, but that was not the case if xylanase was added to brewers rice, presumably due to a lack of substrate in brewers rice [24]. Addition of cellulase to DDGS may theoretically result in release of glucose that may be absorbed in the small intestine [20], but data to demonstrate this effect under practical conditions are lacking.…”

“…Some of the chemicals used to increase fiber digestibility are sodium hydroxide (NaOH) [8–10], ammonium [11, 12], calcium oxide [13], and calcium hydroxide (Ca(OH) 2 ) [14]. Benefits of microbial phytase in terms of increasing the digestibility of phosphorus [15, 16] and calcium [17, 18] are well documented, but cellulase, hemicellulase, xylanase, β-glucanase, α-galactosidase, or carbohydrase mixtures may potentially be used to increase energy and fiber digestibility in feed ingredients and diets [19–24]. There is, however, a lack of information about effects of many of these processing techniques on energy and nutrient digestibility and the utilization of feed by pigs.…”