Martínez-Vallespín B, Ader P, Zentek J
Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Königin-Luise-Str. 49, 14195 Berlin, Germany.
BASF SE, 68623 Lampertheim, Germany.
Poult Sci. 2025 Jun 24;104(9):105473. doi: 10.1016/j.psj.2025.105473.
Phytic acid is the primary storage form of phosphorus (P) in plants and broiler chickens have a limited capability for its utilization. The supplementation of exogenous phytase in feed enables broilers to use the phytate-bound P. The current study evaluated the supplementation of increasing levels of a bacterial hybrid 6-phytase (500, 1,500 and 3,000 FTU/kg feed; groups LP2, LP3 and LP4, respectively) to a low-P, phytate-containing broiler chicken diet (LP1), fed from day 1 to 21 of age. Statistical analysis used a general linear model with linear and quadratic contrasts to assess phytase-level trends. The efficacy of the phytase on performance and ileal digestibility was demonstrated with linear increases in body weight (BW), BW gain, feed intake and apparent ileal digestibility of most of the amino acids, as well as of P (P < 0.05). The increasing levels of phytase led to a linear decrease of jejunal and caecal crypt depth when corrected for BW (P < 0.05), and to a linear decrease of the villus height:crypt depth ratio (P = 0.028). Secretory IgA measured in jejunum digesta showed a trend to a linear increase with the increasing levels of phytase (P = 0.092). The measurement of d-glucosamine and d-galactosamine as markers of mucus secretion in ileum digesta showed differences for d-glucosamine only, with a linear increase of this marker due to the phytase supplementation (P = 0.017). Finally, a trend for increased ex situ glucose transport was observed in Ussing chambers when tissue of the jejunal mucosa of LP1 group was compared with that of LP4 group (P = 0.079). Quadratic effects suggest a stabilizing response in most traits beyond a certain phytase level, indicating a biological plateau. In conclusion, the use of increasing doses of exogenous bacterial hybrid 6-phytase up to 3,000 FTU/kg in broilers from day 1 to 21 of age improved performance and nutrient digestibility as well as some traits related to intestinal physiology and immune response.
植酸是植物中磷（P）的主要储存形式，而肉鸡对其利用能力有限。在饲料中添加外源植酸酶可使肉鸡利用与植酸结合的磷。本研究评估了在1至21日龄的低磷、含植酸的肉鸡日粮（LP1）中添加不同水平的细菌杂交6 - 植酸酶（分别为500、1500和3000 FTU/kg饲料；组LP2、LP3和LP4）的效果。统计分析采用具有线性和二次对比的一般线性模型来评估植酸酶水平趋势。植酸酶对生长性能和回肠消化率的功效表现为体重（BW）、体重增加、采食量以及大多数氨基酸和磷的表观回肠消化率呈线性增加（P < 0.05）。校正体重后，植酸酶水平的增加导致空肠和盲肠隐窝深度呈线性下降（P < 0.05），绒毛高度与隐窝深度比值呈线性下降（P = 0.028）。在空肠食糜中测得的分泌型免疫球蛋白A随植酸酶水平升高呈线性增加趋势（P = 0.092）。在回肠食糜中作为黏液分泌标志物的d - 葡萄糖胺和d - 半乳糖胺的测定结果显示，仅d - 葡萄糖胺存在差异，由于添加植酸酶，该标志物呈线性增加（P = 0.017）。最后，当将LP1组空肠黏膜组织与LP4组进行比较时，在尤斯灌流小室中观察到异位葡萄糖转运有增加趋势（P = 0.079）。二次效应表明，在超过一定植酸酶水平后，大多数性状呈现稳定反应，表明存在生物学平台期。总之，在1至21日龄的肉鸡中使用高达3000 FTU/kg的递增剂量外源细菌杂交6 - 植酸酶可改善生长性能、营养物质消化率以及一些与肠道生理和免疫反应相关的性状。
