title: Using a fibrolytic enzyme in barley-based diets containing wheat dried distillers grains with solubles: ruminal fermentation, digestibility, and growth performance of feedlot steers.
abstract: Two experiments were conducted to evaluate the effects of adding an exogenous fibrolytic enzyme (FE) on ruminal pH and fermentation, digestibility, and growth performance of feedlot beef cattle fed a finishing diet containing wheat dried distillers grains with solubles (DDGS). In Exp. 1, 4 ruminally cannulated Angus heifers (average BW of 807 ± 93.9 kg) were used in a replicated 4 × 4 Latin square design. Treatments were 1) control (CON; 10% barley silage and 90% barley grain-based concentrate), 2) CON diet substituting 30% wheat DDGS for barley grain (WDG), 3) WDG diet supplemented with low FE (WDGL), and 4) WDG diet supplemented with high FE (WDGH). Heifers fed WDG had less (P = 0.01) total tract DM digestibility than heifers fed CON. Increasing FE linearly (P < 0.05) increased starch digestibility without affecting digestibility of other nutrients. Addition of FE also reduced (P = 0.03) ruminal ammonia-N (NH3-N) concentration but did not affect VFA concentration. Moreover, application of FE to wheat DDGS linearly increased in situ ruminal DM (P < 0.01) and NDF (P = 0.02) disappearance after 48 h of incubation. In Exp. 2, 160 yearling steers (initial BW = 495 ± 37.9 kg) were fed the same diets as in Exp. 1. No differences in DMI, final BW, ADG, dietary NEg, or carcass characteristics were observed among diets. However, the steers fed WDG had less (P < 0.05) G:F and greater number of (P < 0.01) abscessed livers than steers fed CON. Increasing FE application in wheat DDGS diets did not affect DMI, final BW, or ADG but tended (P < 0.09) to linearly improve feed efficiency and decreased (P = 0.03) the incidence of abscessed livers. These results demonstrated adverse effects of including wheat DDGS in finishing diets on feed digestion, feed efficiency, and animal health. Application of FE in wheat DDGS-based diets potentially improved starch digestion, protein metabolism in the rumen, feed efficiency, and animal health.
authors.affiliation: Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta T1J 4B1, Canada Key Laboratory for Agro-Ecological Processes in Subtropical Region, Hunan Research Center of Livestock & Poultry Sciences, South-Central Experimental Station of Animal Nutrition and Feed Science in Ministry of Agriculture, Institute of Subtropical Agriculture, The Chinese Academy of Sciences, Changsha, Hunan 410125, China.
authors.forename: Z X
authors.initials: ZX
authors.lastname: He
authors.affiliation: Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta T1J 4B1, Canada.
authors.forename: M L
authors.initials: ML
authors.lastname: He
authors.affiliation: AB Vista Feed Ingredients, Marlborough, Wiltshire SN8 4AN, UK.
authors.forename: N D
authors.initials: ND
authors.lastname: Walker
authors.affiliation: Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta T1J 4B1, Canada.
authors.forename: T A
authors.initials: TA
authors.lastname: McAllister
authors.affiliation: Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta T1J 4B1, Canada wenzhu.yang@agr.gc.ca.
authors.forename: W Z
authors.initials: WZ
authors.lastname: Yang
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000818:Animals; D002417:Cattle / Q000254:growth & development*; D002480:Cellulase / Q000494:pharmacology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004063:Digestion / Q000187:drug effects / Q000502:physiology*; D005285:Fermentation / Q000187:drug effects / Q000502:physiology*; D001467:Hordeum / Q000737:chemistry*; D008100:Liver Abscess; D008297:Male; D012417:Rumen / Q000502:physiology*; D014908:Triticum / Q000737:chemistry; D014995:Xylosidases / Q000494:pharmacology*
chemical_list: D000641:Ammonia; D014995:Xylosidases; D002480:Cellulase
keywords: beef cattle; digestibility; feed efficiency; fibrolytic enzyme; finishing diet; wheat dried distillers grains with solubles