Yan Ming, Deng Ganqi, Yu Peiqiang
Department of Animal and Poultry Science, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
J Anim Physiol Anim Nutr (Berl). 2023 Mar;107(2):379-393. doi: 10.1111/jpn.13731. Epub 2022 May 19.
To our knowledge, there is limited study on the relationship between the molecular structure of feed and nutrient availability in the ruminant system. The objective of this study is to use advanced vibrational molecular spectroscopy (attenuated total reflection [ATR]-Fourier transform infrared [FT/IR]) to reveal carbohydrate molecular structure properties of faba bean partitions (stem, leaf, whole pods [WP], and whole plant) and faba bean silage before and after rumen incubation in relation to nutrient availability and supply to dairy cattle. The study included the correlation between carbohydrate-related spectral profiles and chemical profiles, feed energy values, Cornell Net Carbohydrate and Protein System carbohydrate fractions, and rumen degradation parameters of faba bean samples (whole crop, stem, leaf, WP, and silage) before and after rumen incubation. FTIR spectra of faba bean sample before and after 12 and 24 h rumen incubations were collected with JASCO FT/IR-4200 with ATR at mid-IR range (ca. 4000-700 cm ) with 128 scans and at 4 cm resolution. The univariate molecular spectral analysis was carried out using OMNIC software. The results show that ATR-FT/IR spectroscopic technique could detect the change of microbial digestion to carbohydrate-related molecular structure. The spectral parameters of feed rumen incubation residues had a stronger correlation with less degradable carbohydrate fractions (neutral detergent fiber, acid detergent fiber, acid detergent lignin, hemicellulose, and cellulose) while spectral profiles of original faba samples had a stronger correlation with easily degradable carbohydrate fractions (starch). In conclusion, rumen degradation of carbohydrate contents can be reflected in the change of its molecular spectral profiles. The study shows that vibrational molecular spectroscopy (ATR-FT/IR) shows high potential as a fast analytical tool to evaluate and predict nutrient supply in the ruminant system.
据我们所知，关于反刍动物系统中饲料分子结构与养分利用率之间关系的研究有限。本研究的目的是使用先进的振动分子光谱法（衰减全反射[ATR]-傅里叶变换红外[FT/IR]），揭示蚕豆各部分（茎、叶、全荚[WP]和全株）以及瘤胃培养前后蚕豆青贮饲料的碳水化合物分子结构特性与奶牛养分供应和利用率之间的关系。该研究包括碳水化合物相关光谱特征与化学特征、饲料能量值、康奈尔净碳水化合物和蛋白质系统碳水化合物组分以及瘤胃培养前后蚕豆样品（全株作物、茎、叶、WP和青贮饲料）的瘤胃降解参数之间的相关性。使用配备ATR的JASCO FT/IR-4200在中红外范围（约4000-700 cm）以128次扫描和4 cm分辨率收集瘤胃培养12小时和24小时前后蚕豆样品的FTIR光谱。使用OMNIC软件进行单变量分子光谱分析。结果表明，ATR-FT/IR光谱技术可以检测到微生物对碳水化合物相关分子结构的消化变化。饲料瘤胃培养残渣的光谱参数与难降解碳水化合物组分（中性洗涤纤维、酸性洗涤纤维、酸性洗涤木质素、半纤维素和纤维素）的相关性更强，而原始蚕豆样品的光谱特征与易降解碳水化合物组分（淀粉）的相关性更强。总之，碳水化合物含量的瘤胃降解可以通过其分子光谱特征的变化来反映。该研究表明，振动分子光谱法（ATR-FT/IR）作为一种快速分析工具，在评估和预测反刍动物系统中的养分供应方面具有很高的潜力。
