Effect of flavonoid compounds from Flemingia Macrophylla on milk composition of lactating goat in the tropics

Abstract

Trees and shrubs are a component of most natural pastures for goat diets. Condensed tannins (CT) and flavonols are secondary metabolites called flavonoids that are found in many tree and shrubs leaves. Forage from flemingia (Flemingia macrophylla), a woody tropical leguminous shrub, recently introduced in Brazil, contains several types of flavonoid compounds whose effects on goat milk composition are unknown. The objective of this study was to evaluate milk composition of crossbred dairy goats fed Tifton 85 (Cynodon spp. hybrid) grass replaced by flemingia. Treatments consisted of six diets containing 0, 12.5 and 25% flemingia with or without PEG. Condensed tannin from flemingia which were present at 105 g/kg DM had no effect on milk physico-chemical properties and little effect on milk fatty acids (FA). Diets with PEG resulted in less caprylic (C8:0), capric (C10:0), lauric (C12:0) and myristic (14:0) fatty acids compared to those goats fed no PEG. The addition of PEG also promoted a greater percentage of margaric acid (C17:0) and a lower freezing point of milk. Differences observed among diets with PEG suggest CT could be negatively correlated with these FA. Results indicate that the use of flemingia leaves to replace Tifton 85 hay in dairy goat diets as a strategy to produce healthier milk should be further explored.