Benavides-Infante Angie P, Rodrigues Lucas A, Socha Mike T, Schweer Wesley P, Levesque Crystal L, Perez-Palencia Jorge Y
Department of Animal Science, South Dakota State University, 1097 North Campus Drive, Brookings, SD, 57007, USA.
Zinpro Corporation, Eden Prairie, MN, 55344, USA.
J Anim Sci Biotechnol. 2025 Jul 18;16(1):102. doi: 10.1186/s40104-025-01239-0.
Isoacids are the product of branched-chain amino acid fermentation and are naturally produced in the hindgut by microbial fermentation. In ruminants, supplementation of isoacids as a feed additive improves fiber utilization, with a positive impact on animal productivity. However, information on how isoacids impact nutrient digestibility in swine is limited. The objective of this experiment was to determine the optimal inclusion level of an isoacid blend product based on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients and fermentation products in the ileal digesta and feces of growing pigs fed a corn-soybean meal diet.
Twelve ileal cannulated pigs (20.9 ± 0.6 kg) were used in a 5-period crossover design with 6 diets and 2 replicate pigs in each period. Dietary treatments consisted of increasing levels (0%, 0.5%, 0.75%, 1%, 1.25%, and 1.5%) of an isoacid blend (isobutyrate, isovalerate, and 2-methyl butyrate, 1:1:1) added to a corn-soybean meal basal diet. Each experimental period consisted of 14 d: 10 d for acclimatization to the diets, 2 d for fecal collection, and 2 d for digesta collection.
Isoacids supplementation quadratically improved the AID of hemicellulose (P < 0.05) and tended to improve the AID of crude fiber (P < 0.1). The AID of most indispensable amino acids (except Met + Cys, Trp, and Val) as well as the ATTD of crude protein, gross energy, neutral detergent fiber, and hemicellulose improved or tended to improve linear or quadratically (P < 0.05 or P < 0.1). In addition, the ATTD values of Arg, His, Ile, Leu, Met + Cys, Phe, Thr, and Val increased quadratically (P < 0.05). Collectively, 1% of isoacids inclusion resulted in the greatest response. Furthermore, isoacids supplementation tended to increase (P = 0.071, quadratically) the concentration of ammonia and decreased (P < 0.05) the concentrations of acetic acid and total volatile fatty acids with a tendency to decrease (P = 0.064) isovaleric acid in the ileal digesta. In fecal samples, the proportion of acetic acid decreased (P < 0.05) quadratically, whereas the proportions of propionic, valeric, and caproic acids tended to increase linearly and/or quadratically (P < 0.1).
Isoacids supplementation at 1% in swine diets can improve nutrient digestibility, particularly amino acids and fiber at the ileal level and ATTD of crude protein, gross energy, and hemicellulose.
异酸是支链氨基酸发酵的产物，由微生物在肠道后段自然发酵产生。在反刍动物中，添加异酸作为饲料添加剂可提高纤维利用率，对动物生产性能有积极影响。然而，关于异酸对猪营养物质消化率影响的信息有限。本试验旨在根据生长猪采食玉米 - 豆粕型日粮时回肠食糜和粪便中营养物质及发酵产物的表观回肠消化率（AID）和表观全肠道消化率（ATTD），确定异酸混合产品的最佳添加水平。
选用12头回肠造瘘猪（体重20.9 ± 0.6 kg），采用5期交叉设计，共6种日粮，每期2头重复猪。日粮处理为在玉米 - 豆粕基础日粮中添加不同水平（0%、0.5%、0.75%、1%、1.25%和1.5%）的异酸混合物（异丁酸、异戊酸和2 - 甲基丁酸，比例为1:1:1）。每个试验期为14天：10天适应日粮，2天收集粪便，2天收集食糜。
添加异酸可使半纤维素的AID呈二次曲线改善（P < 0.05），粗纤维的AID有改善趋势（P < 0.1）。大多数必需氨基酸（蛋氨酸 + 半胱氨酸、色氨酸和缬氨酸除外）的AID以及粗蛋白、总能、中性洗涤纤维和半纤维素的ATTD呈线性或二次曲线改善或有改善趋势（P < 0.05或P < 0.1）。此外，精氨酸、组氨酸、异亮氨酸、亮氨酸、蛋氨酸 + 半胱氨酸、苯丙氨酸、苏氨酸和缬氨酸的ATTD值呈二次曲线增加（P < 0.05）。总体而言，添加1%异酸产生的反应最大。此外，添加异酸有使回肠食糜中氨浓度呈二次曲线增加的趋势（P = 0.071），乙酸和总挥发性脂肪酸浓度降低（P < 0.05），异戊酸浓度有降低趋势（P = 0.064）。在粪便样本中，乙酸比例呈二次曲线下降（P < 0.05），而丙酸、戊酸和己酸比例呈线性和/或二次曲线增加趋势（P < 0.1）。
猪日粮中添加1%异酸可提高营养物质消化率，特别是回肠水平的氨基酸和纤维以及粗蛋白、总能和半纤维素的ATTD。
