高淀粉玉米对育肥肉牛生产性能和胴体品质的影响。

Effects of high-amylase corn on performance and carcass quality of finishing beef heifers.

机构信息

Department of Animal Sciences and Industry, Kansas State University, Manhattan, KS.

出版信息

J Anim Sci. 2020 Oct 1;98(10). doi: 10.1093/jas/skaa302.

DOI:10.1093/jas/skaa302

PMID:32910163

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC7584274/

Abstract

Developed initially for use in fuel ethanol production, Enogen Feed Corn (EFC; Syngenta Crop Protection) is genetically modified to express high concentrations of α-amylase in the corn kernel. Experiments were conducted to evaluate processing characteristics of EFC, in vitro digestion, and effects on feedlot performance, carcass characteristics, and liver abscess incidence. Experiment 1 used a randomized complete block design (3 × 3 × 5 factorial) to evaluate starch availability, in situ dry matter disappearance (ISDMD), in vitro gas production (IVGP), and volatile fatty acid (VFA) profiles of in vitro cultures. Grains (EFC or mill-run control [CON]) were flaked to a density of 360 g/L, and mixtures with 0%, 25%, 50%, 75%, or 100% EFC were prepared. Grains were tempered with added moisture (0%, 3%, or 6%) prior to steam conditioning for 15, 30, or 45 min. No two- or three-way interactions were observed. Adding moisture improved starch availability (linear; P < 0.01), and tended to improve ISDMD (linear, P = 0.06). Steam conditioning for 30 min improved starch availability, IVGP, and production of acetate, propionate, butyrate, valerate, and total VFA (P < 0.01) compared with conditioning for 15 or 45 min. Starch availability, ISDMD, IVGP, acetate, propionate, valerate, and total VFA production increased with an increasing proportion of EFC (linear, P < 0.01). Experiment 2 used 700 beef heifers (394 ± 8.5 kg initial body weight [BW]) fed finishing diets with steam-flaked corn as CON or EFC for 136 d. Targeting similar starch availabilities, grains were processed to 360 g/L (CON) and 390 g/L for CON and EFC, respectively. Heifers were blocked by BW, stratified, and then randomly assigned to 28 dirt-surfaced pens (25 animals per pen). Dry matter intakes were similar between treatments (P = 0.78), but cattle fed EFC had greater average daily gain (P < 0.01), improving feed efficiency by 5% (P < 0.01). Hot carcass weight was 6 kg greater for EFC cattle (P <0.01) than CON. No differences were observed for longissimus muscle area (P = 0.89), 12th-rib fat thickness (P = 0.21), or USDA yield grade (P = 0.13). Cattle fed CON had greater marbling scores than EFC (P = 0.04), but this did not affect the USDA quality grade (P > 0.33). Cattle fed EFC had 23% fewer abscessed livers than CON (P = 0.03). High-amylase corn may be used to improve microbial digestion, mill-throughput, and cattle performance, and it may mitigate liver abscesses.

摘要

最初开发用于燃料乙醇生产的 Enogen 饲用玉米（EFC；先正达作物保护）经过基因改造，在玉米粒中表达高浓度的α-淀粉酶。进行了实验来评估 EFC 的加工特性、体外消化以及对育肥性能、胴体特征和肝脓肿发生率的影响。实验 1 采用随机完全区组设计（3×3×5 析因）来评估淀粉利用率、原位干物质消失率（ISDMD）、体外产气量（IVGP）和体外培养物的挥发性脂肪酸（VFA）谱。将谷物（EFC 或轧碎对照[CON]）压片至密度为 360g/L，并制备 0%、25%、50%、75%或 100%EFC 的混合物。谷物用添加的水分（0%、3%或 6%）调湿，然后进行蒸汽调节 15、30 或 45min。未观察到两因素或三因素相互作用。添加水分可提高淀粉利用率（线性；P<0.01），并倾向于提高 ISDMD（线性，P=0.06）。与 15 或 45min 相比，蒸汽调节 30min 可提高淀粉利用率、IVGP 以及乙酸、丙酸、丁酸、戊酸和总 VFA 的产生（P<0.01）。淀粉利用率、ISDMD、IVGP、乙酸、丙酸、戊酸和总 VFA 的产生随 EFC 比例的增加而增加（线性，P<0.01）。实验 2 使用 700 头肉牛（394±8.5kg 初始体重[BW]）在育肥期用蒸汽压片玉米作为对照（CON）或 EFC 饲料喂养 136d。为了达到相似的淀粉利用率，将谷物加工至 360g/L（CON）和 390g/L 用于 CON 和 EFC。根据 BW 进行分组，然后进行分层，并随机分配到 28 个土面围栏（每围栏 25 头牛）。处理之间的干物质摄入量相似（P=0.78），但饲喂 EFC 的牛的平均日增重更大（P<0.01），提高了 5%的饲料效率（P<0.01）。EFC 牛的热胴体重比 CON 牛高 6kg（P<0.01）。12 肋脂肪厚度（P=0.21）或 USDA 产肉等级（P=0.13）没有差异。饲喂 CON 的牛的大理石花纹评分高于 EFC（P=0.04），但这不会影响 USDA 质量等级（P>0.33）。饲喂 EFC 的牛的肝脓肿数量比 CON 牛少 23%（P=0.03）。高淀粉酶玉米可用于改善微生物消化、磨粉产量和牛的性能，并可能减轻肝脓肿的发生。