Interactive Association Between Molecular Structure Spectral Profiles and Nutrient Utilization and Availability of Leaf, Stem, Pods, and Whole Plant Faba Bean Forage in Ruminants Before and After Rumen Incubation

ABSTRACT The general objectives of this study were to: (1) compare structural, physiochemical, and nutritional characterization among faba bean samples (stem, leaf, whole pods, whole plant and whole plant silage) and (2) use different parts of faba bean, whole plant faba bean and whole plant faba bean silage as references to study the effect of rumen digestion on the change of its spectral structure and its association to protein and carbohydrate digestion and metabolism characteristics. The faba bean samples used for this research were from three different plots in Yellow Creek, Saskatchewan with 97 days maturity (late pod stage) and the variety used was CDC Snowdrop. This research consists of three Projects. In Chapter 3, chemical analyses, energy parameters, CNCPS fractions, rumen degradation kinetics, N to energy synchronization, intestinal digestion and metabolizable protein supply prediction with NRC-2001 and DVE/OEB systems were conducted. In Chapter 4, both univariate and multivariate analyses of FTIR spectroscopy were conducted for selected spectral parameters and spectral regions in original and 12 and 24 h incubation residue samples. In Chapter 5, interactive association between nutritional data in Chapter 3 and spectral data in Chapter 4 were studied. Significance was declared at P 0.1) metabolizable protein supply and FMV. But in DVE/OEB system, WP had the highest metabolizable protein supply and FMV; WPL was only numerically higher than silage in metabolizable protein supply and FMV. In Chapter 4, as for protein related spectral parameters, peak height of beta sheet, amide I, peak area of amide II and area ratio of amide I to amide II, spectral intensity was decreased with increasing time of incubation. In other spectral parameters, incubation time was interacted with different types of faba bean samples. As for carbohydrate related spectral parameters of total carbohydrate first peak (TC1) height and cellulosic compounds (CEC) peak height and peak area, spectral intensity was increased after incubated in the rumen. Faba bean samples significantly interacted with incubation time for other spectral profiles. With multivariate analyses, it is found that (1) Original samples can be discriminate from incubation residue samples; (2) 12 and 24 h incubation samples were grouped together. As a result, spectral features were altered during first 12 h of rumen incubation. In Chapter 5, DVE/OEB model compared with NRC-2001 model had stronger correlation with protein related spectral profiles of faba bean. CP, SCP and acid detergent insoluble crude protein (ADICP) had stronger correlation with original samples spectral profiles, NDICP had stronger correlation with incubation residue spectral profiles. In addition, readily digestible carbohydrate fractions had stronger correlation with original samples spectral profiles. Less degradable and undegradable carbohydrate fraction had stronger correlation with 12 and 24 h rumen incubation residue spectral profiles. Furthermore, DVE, effective degradable crude protein (EDCP), FMV, CNCPS carbohydrate subtractions of CB1, CB2 and CC, non-fiber carbohydrate (NFC), starch and total digestible NFC were precisely predicted (regression coefficient greater than 0.90) using original and degradation residues spectral profiles. In general, carbohydrate and protein related spectral features could be used as indicators for faba bean nutritional evaluation in dairy cattle; whole plant faba bean, whole pods faba bean and faba silage can be used as potential feed ingredient for dairy cows