Nutritive value of the olive leaf: effects of cultivar, season of harvesting and system of drying

Abstract

SUMMARYLeaves of olive trees (Olea europaea L.) of eight cultivars, Manzanilla, Picual, Hojiblanca, Edremit, Conservolia, Picholine-Marroqui, Chemlali and Frantoio, were collected in different seasons and years in Córdoba, Spain. Their chemical composition and in vitro organic matter digestibility values were determined. Differences in composition and nutritive value between cultivars, years and seasons were studied in Manzanilla, Picual and Hojiblanca, the three most important local cultivars. There were significant differences both between cultivars and seasons (P < 0·05) and a non-significant difference between years.The effect of various drying procedures (fresh, oven-dried, air-dried indoors or air-dried outdoors) on chemical composition, in vitro digestibility and in vivo digestibility in sheep was also examined. The in vivo organic matter digestibility of fresh leaves was significantly higher than that of dried leaves. No difference was found between leaves air-dried indoors and oven-dried leaves. However, leaves air-dried outdoors were significantly less digestible. Quick drying in an oven reduced the digestibility of crude protein and acid detergent fibres compared to air drying indoors. There was a significant decrease in digestibility of 11% when leaves were dried separated from the branches as compared to leaves dried on the branches.