Yu Yao, Wang Yuming, Ge Kaijing, Chen Jiang, Xie Jingjing, Zou Yi, Liu Songbai, Tan Huize, Zhao Feng
The State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
Wen's Foodstuffs Group Co. Ltd., Yunfu 527400, China.
Poult Sci. 2025 Feb;104(2):104738. doi: 10.1016/j.psj.2024.104738. Epub 2024 Dec 25.
This experiment compared amino acid (AA) digestibility assessed by 2 in vitro methods using a computer-controlled simulated digestion system and in vivo assay for corn, soybean meal, casein, corn gluten meal, cottonseed meal, rapeseed meal and a corn-soybean meal diet. In vitro method 1 simulated gizzard digestion at pH 2.0, followed by small intestinal digestion, and the subsequent clearance of the digested product from dialysis tubing. In vitro method 2 was similar to the first method, except that pH in gizzard digestion was 3.5 and there was an enzymatic inactivation stage before digested product clearance. Each in vitro method included 5 replicates per treatment, with 1 digestion tube per replicate. Cecectomized Chinese yellow-feathered roosters (average body weight of 2.73 kg) were assigned to 1 of the following treatments: corn, soybean meal, or a corn-soybean meal diet (n = 6 replicates of 3 roosters per treatment); or casein, corn gluten meal, cottonseed meal, or rapeseed meal (n = 5 replicates of 3 roosters per treatment) in a completely randomized design to assess digestibility of AA. The relative deviation was within 5% comparing methods 1, 2 and in vivo method for 87.5% and 92.0% of all AA digestibility measured of 7 samples, respectively. Significant linear relationships were observed between in vitro methods 1 and 2 for the digestibility of 14 AAs (except for Cys) and total amino acid (TAA) (r ≥ 0.778; P < 0.05). Significant linear relationships were found between in vitro method 1 and in vivo results for 9 AAs (except for His, Ile, Asp, Cys, Glu and Ser) and TAA (r ≥ 0.866; P < 0.05). Similarly, significant linear relationships between in vitro method 2 and in vivo findings were observed for 11 AAs (except for His, Lys, Cys and Glu) and TAA (r ≥ 0.776; P < 0.05). The linear regression of in vivo assay on in vitro method 1 or 2 overlapped with Y = X for 7 AA and TAA or 10 AA and TAA, respectively. Our findings suggest in vitro method 2 is superior to method 1 for estimating AA digestibility of yellow-feathered roosters, this indicates that gizzard pH or inactivation of enzymes modulates the effectiveness of in vitro digestibility assays.
本实验比较了两种体外方法（使用计算机控制的模拟消化系统）和体内试验评估的玉米、豆粕、酪蛋白、玉米蛋白粉、棉籽粕、菜籽粕以及玉米 - 豆粕型日粮的氨基酸（AA）消化率。体外方法1模拟了pH 2.0条件下的肌胃消化，随后是小肠消化，以及消化产物从透析管中的后续清除。体外方法2与第一种方法类似，不同之处在于肌胃消化的pH为3.5，并且在消化产物清除之前有一个酶失活阶段。每种体外方法每个处理包括5个重复，每个重复1个消化管。将切除盲肠的中国黄羽肉鸡（平均体重2.73 kg）分配到以下处理之一：玉米、豆粕或玉米 - 豆粕型日粮（每个处理n = 6个重复，每个重复3只鸡）；或酪蛋白、玉米蛋白粉、棉籽粕或菜籽粕（每个处理n = 5个重复，每个重复3只鸡），采用完全随机设计来评估氨基酸的消化率。对于7个样品所测定的所有氨基酸消化率，方法1、方法2与体内方法相比，相对偏差分别在87.5%和92.0%的范围内，偏差在5%以内。在体外方法1和方法2之间，观察到14种氨基酸（除半胱氨酸外）和总氨基酸（TAA）的消化率存在显著线性关系（r≥0.778；P<0.0?5）。在体外方法1与体内结果之间，发现9种氨基酸（除组氨酸、异亮氨酸、天冬氨酸、半胱氨酸、谷氨酸和丝氨酸外）和TAA存在显著线性关系（r≥0.866；P<0.05）。同样，在体外方法2与体内结果之间，观察到11种氨基酸（除组氨酸、赖氨酸、半胱氨酸和谷氨酸外）和TAA存在显著线性关系（r≥0.776；P<0.05）。体内试验相对于体外方法1或方法2 的线性回归分别与7种氨基酸和TAA或10种氨基酸和TAA的Y = X重叠。我们的研究结果表明，在估计黄羽肉鸡氨基酸消化率方面，体外方法2优于方法1，这表明肌胃pH或酶失活调节了体外消化率测定的有效性。
