Effect of ammonia fiber expansion-treated wheat straw and a recombinant fibrolytic enzyme on rumen microbiota and fermentation parameters, total tract digestibility, and performance of lambs. (5th May 2020)

• Record Type: Journal Article
• Authors: Ribeiro, Gabriel O; Gruninger, Robert J; Jones, Darryl R; Beauchemin, Karen A; Yang, Wen Zhu; Wang, Yuxi; Abbott, D Wade; Tsang, Adrian; McAllister, Tim A
• Is Part Of: Journal of animal science. Volume 98:Number 5(2020)
• Publication Date: 2020-05-05
• Subjects: AFEX -- ammoniation -- lamb -- rumen -- xylanase -- wheat straw; Livestock -- Periodicals; Livestock; Electronic journals; Periodicals; 636.005
• DOI: 10.1093/jas/skaa116
• Languages: English
• ISSNs: 0021-8812

Abstract

Abstract: The objective of this study was to evaluate the effect of ammonia fiber expansion (AFEX )-treated wheat straw pellets and a recombinant fibrolytic enzyme on the rumen microbiome, rumen fermentation parameters, total tract diet digestibility, and performance of lambs. Eight rumen cannulated wethers and 60 lambs ( n = 15 per diet, 8 rams and 7 ewes) were used in a replicated 4 × 4 Latin square design digestibility study and a complete randomized growth performance study, respectively. Four treatment diets were arranged in a 2 × 2 factorial structure with AFEX wheat straw (0% or 30% AFEX straw pellets on a dietary DM basis replacing alfalfa hay pellets) and fibrolytic enzyme (with or without XYL10C, a β-1, 4-xylanase, from Aspergillus niger ) as main factors. Enzyme was applied at 100 mg/kg of diet DM, 22 h before feeding. Rumen bacteria diversity Pielou evenness decreased ( P = 0.05) with AFEX compared with the control diet and increased ( P < 0.01) with enzyme. Enzyme increased ( P ≤ 0.02) the relative abundancies of Prevotellaceae UCG-004, Christensenellaceae R-7 group, Saccharofermentans, and uncultured Kiritimatiellaeota. Total protozoa counts were greater ( P ≤ 0.04) in the rumen of lambs fed AFEX compared with control, with enzyme reducing ( P ≤ 0.05) protozoa counts for both diets. Digestibility of DM did not differ ( P > 0.10) among diets, but digestibility of CP was reduced ( P = 0.001), and digestibility of NDF and ADF increased ( P < 0.05) as AFEX replaced alfalfa. Compared with control, AFEX promoted greater DMI ( P = 0.003) and improved ADG up to 42 d on feed ( P = 0.03), but not ( P = 0.51) over the full ~94-d experiment. Consequently, overall G:F was reduced ( P = 0.04) for AFEX when compared with control (0.188 vs. 0.199), but days on feed were lower ( P = 0.04) for AFEX (97 vs. 91 d). Enzyme improved DMI of AFEX up to day 70 ( P = 0.01), but did not affect DMI of the control diet. Enzyme addition improved ADG of lambs fed both diets in the first 28 d ( P = 0.02), but not over the entire feeding period ( P ≥ 10). As a result, G:F was improved with enzyme for the first 28 d ( P = 0.04), but not overall ( P = 0.45). This study shows that AFEX-treated wheat straw can replace alfalfa hay with no loss in lamb growth performance. Additionally, the enzyme XYL10C altered the rumen microbiome and improved G:F in the first month of the feeding.