Molecular Structures and Metabolic Characteristics of Protein in Brown and Yellow Flaxseed with Altered Nutrient Traits

摘要

The objectives of this study were to investigate the chemical profiles; crude protein (CP) subffactionsj ruminal CP degradation characteristics and intestinal digestibility of rumen undegraded protein (RUP); and protein molecular structures usirig molecular spectroscopy of newly developed yellow-seeded flax (Linutn usitatissimutn L.). Seeds from two yellow flaxseed breeding lines arid two brown flaxseed varieties were evaluated. The yellow-seeded lines, had higher (P < 0.001) contents of oil (44.54 vs 41.4296 dry matter (DM)) and CP (24.94 vs 20.91% DM) compared to those of the brown-seeded varieties. The CP in yellow seeds contairied lower (P < '0.01). contents of true protein subtraction (81.31 vs 92.7196 CP) arid more (P < 0,001) extensively degraded (70.8:vs 64.996 CP) in rumen resulting in lower (P < 0.001) content of RUP (29.2 vs 35.196 CP) than that in the brown-seeded varieties. However, the total supply of digestible RUP was not significantly different between the two seed types. Regression equations based on protein molecular structural features gave relatively good estimation for the contents of CP (R~2~ 0.87), soluble CP (R~2 = 0.92), RUP (R~2 = 0.97), and intestinal digestibility of RUP (R~2 = 0.71). In conclusion, molecular spectroscopy can be used to rapidly characterize feed protein molecular structures and predict their nutritive value.