Galli Gabriela M, Forero Salamanca Alejandra, Haydon Keith, Levesque Crystal L, Perez-Palencia Jorge Y
Department of Animal Science, South Dakota State University, Brookings, SD 57007, USA.
CJ Bio America Inc., Downers Grove, IL 60515, USA.
Animals (Basel). 2024 Nov 13;14(22):3255. doi: 10.3390/ani14223255.
(1) Background: This study aimed to evaluate the effects of dietary xylanase addition on growth performance, nutrient digestibility, volatile fatty acids, and digesta viscosity at different digestive sites in weaned pigs fed wheat-soybean meal-based diets with reduced metabolizable energy. (2) Methods: A total of 312 weaned pigs (5.1 ± 0.9 kg, 20 ± 2 days of age) were assigned to one of six dietary treatments. The experimental diets were formulated in a three-phase nursery feeding program: phase 1 (d0-d7), phase 2 (d8-d21), and phase 3 (d22-d42). The experimental diets consisted of a wheat-soybean meal-based diet formulated to meet pig requirements (positive control, PC); the PC diet with a reduction of 100 kcal of metabolizable energy (ME) (negative control, NC); and the NC diet with either 900, 1800, 3600, or 7200 units of xylanase. Feed disappearance and body weight were measured at d7, 14, 21, and 42 in the nursery phase. The pen fecal score was assessed daily from d0 to d14 and three times a week from d15 to d28. On d21-d24 of the experiment (12 pigs per day), one pig per pen was selected for sample collection: ileal, cecal, and mid-colon digesta for viscosity and ileal digesta, feces for nutrient digestibility, and feces and cecal digesta for the measurement of volatile fatty acid. (3) Results: The addition of xylanase to the NC diets did not improve pig growth performance (body weight, feed conversion ratio, and average daily gain; > 0.10) during the entire nursery phase. In Week 2 and Week 3, pigs fed xylanase had a lower (χ2 < 0.05) incidence of fecal scores 3 and 4 (diarrhea) than the PC and NC diets. In addition, the apparent total tract digestibility of neutral detergent fiber and acid detergent fiber increased linearly ( < 0.1) in response to xylanase addition. Xylanase addition (900 to 7200 U) decreased digesta viscosity in the colon compared to the PC and NC diets. Furthermore, xylanase addition resulted in a lower ( < 0.05) concentration of acetic, propionic, butyric, valeric, and total volatile fatty acid in cecal samples compared to PC. The addition of xylanase resulted in greater acetic and valeric acid concentrations in cecal samples compared to the NC group ( < 0.10). (4) Conclusions: Xylanase addition can improve nutrient digestibility, particularly at the total tract level, and reduce viscosity in the hindgut, which could be related to decreasing the occurrence of looseness. However, its impact on growth performance was minimal in wheat-soybean meal-based diets with a reduction of 100 kcal of ME.
（1）背景：本研究旨在评估在饲喂低代谢能小麦 - 豆粕型日粮的断奶仔猪不同消化部位添加木聚糖酶对生长性能、养分消化率、挥发性脂肪酸和食糜黏度的影响。（2）方法：总共312头断奶仔猪（体重5.1±0.9千克，20±2日龄）被分配到六种日粮处理组之一。实验日粮按照三阶段保育期饲养方案配制：第1阶段（d0 - d7）、第2阶段（d8 - d21）和第3阶段（d22 - d42）。实验日粮包括按照满足猪营养需求配制的小麦 - 豆粕型日粮（正对照，PC）；代谢能降低100千卡的PC日粮（负对照，NC）；以及添加900、1800、3600或7200单位木聚糖酶的NC日粮。在保育期的第7、14、21和42天测量采食量和体重。从d0到d14每天评估栏内粪便评分，从d15到d28每周评估三次。在实验的d21 - d24（每天12头猪），每栏选择一头猪进行样本采集：采集回肠、盲肠和结肠中段食糜用于黏度测定，采集回肠食糜、粪便用于养分消化率测定，采集粪便和盲肠食糜用于挥发性脂肪酸测定。（3）结果：在整个保育期，向NC日粮中添加木聚糖酶并未改善猪的生长性能（体重、饲料转化率和平均日增重；P＞0.10）。在第2周和第3周，饲喂木聚糖酶的猪粪便评分为3和4（腹泻）的发生率低于PC和NC日粮（χ²＜0.05）。此外，随着木聚糖酶添加量的增加，中性洗涤纤维和酸性洗涤纤维的表观全肠道消化率呈线性增加（P＜0.1）。与PC和NC日粮相比，添加木聚糖酶（900至7200单位）可降低结肠食糜黏度。此外，与PC相比，添加木聚糖酶导致盲肠样本中乙酸、丙酸、丁酸、戊酸和总挥发性脂肪酸的浓度降低（P＜0.05）。与NC组相比，添加木聚糖酶导致盲肠样本中乙酸和戊酸浓度升高（P＜0.10）。（4）结论：添加木聚糖酶可提高养分消化率，尤其是在全肠道水平，并降低后肠黏度，这可能与减少腹泻的发生有关。然而，在代谢能降低100千卡的小麦 - 豆粕型日粮中，其对生长性能的影响最小。
