RECYCLING OF OLIVE OIL BY PRODUCTS - POSSIBILITIES OF UTILIZATION IN ANIMAL NUTRITION

Olive tree culture is especially important in the Mediterranean area, Spain being first as regards total culture surface (2 121 181ha) and n umber of productive trees (180 000). Both olive tree culture and olive oil industry produce large amounts of by-products. It has been estima ted that pruning produces 25kg of by-products (twigs and leaves) per t ree per year. Leaves represent 5% of the weight of olives in oil extra ction. On the other hand, the olive oil industry produces 35kg of soli d waste (crude olive cake) and 1001 of liquid waste (oil mill wastewat ers) per 100 kg of treated olives. Such substantial amounts of by-prod ucts may have harmful effects on the environment. Consequently, many a lternative utilizations of byproducts have been considered. One import ant alternative from the quantitative point of view is their utilizati on as a source of nutrients for animals. Information concerning chemic al and nutritional characteristics of the various types of olive tree culture by-products and, particularly, of those by-products resulting from the new industrial procedures applied to olive oil extraction mus t be generated in order to achieve efficient uses of such by-products in animal feeding. The possibilities of different chemical and biologi cal methods for the nutritive evaluation of olive tree culture and oli ve oil industry by-products have also to be investigated. Olive tree c ulture and olive oil industry by-products could play a crucial role as sources of local feeds for small ruminants. They may also contribute to the development of efficient and environmentally conservative exten sive animal production systems within Mediterranean semi-arid ecosyste ms. (C) 1997 Elsevier Science Limited.