MOLECULAR STRUCTURAL, PHYSIOCHEMICAL AND NUTRITIONAL CHARACTERIZATION OF NEW LINES OF BRASSICA CARINATA AND THE CO-PRODUCTS
Brassica carinata is widely used in bio-fuel industry recently because of its high oil content and good resistance. Carinata seeds contain 33% oil, 34% protein, 8% oleic acid (total fatty acids basis), 42% erucic acid (total fatty acids basis), 16% linoleic acid and 13% linolenic acid (total fatty acids basis), and 120 µmol/g glucosinolates. The co-product after oil extraction, carinata meal, is high in protein and low in fiber content. However, the molecular structural, nutritional and metabolic characteristics of yellow and brown carinata seeds of newly developed Brassica carinata lines from Agriculture and Agri-Food Canada (AAFC) and carinata co-products as feed ingredients are lacking. The objectives of this research were to investigate: 1) the nutritional and digestive characteristics of carinata seeds and carinata co-products for dairy cattle, 2) the molecular structural features of carinata seeds and carinata co-products, and 3) the relationship of molecular structural features to nutritional bioavailability. Yellow and brown seeds of new carinata lines were collected and compared to canola seeds from newly bred lines and a commercial cultivar. Carinata co-products, carinata meal and hexane-extracted carinata presscake, were compared with canola meal. Chemical profiles, energy values, rumen degradation kinetics of nutrients and intestinal digestion of protein were investigated, then truly absorbed protein supply to dairy cattle was predicted based on the DVE/OEB system and the NRC Dairy model. The molecular structural spectral characteristics were detected by the Fourier Transform Infrared (FTIR) vibrational spectroscopy for protein and carbohydrate related functional groups. Lastly, the relationship between nutritional values and molecular structural spectral parameters was revealed by correlation and regression studies. The results showed: 1) carinata seeds and the co-products were lower in fiber content but higher in protein; 2) carinata seeds had higher rumen degraded protein and metabolizable protein supply in dairy cows compared with canola seeds; the two carinata co-products had higher rumen degraded protein than canola meal, but had lower intestinal digested protein; 3) both carinata seeds and co-products were higher in glucosinolates, most of which was allyl glucosinolate; 4) the hexane-extracted carinata presscake in this study had higher energy value, but showed lower intestinal absorbed protein supply to dairy cattle compared with carinata meal; 5) there were significant protein and carbohydrate structural differences among carinata and canola seeds, and among the three co-products; and 6) protein and carbohydrate structural spectral parameters had relationship with nutrient digestive features, could be used to predict nutrient bioavailability in dairy cattle.
carinata, canola, dairy nutrition, molecular structure
Master of Science (M.Sc.)
Agricultural and Bioresource Engineering