In vitro evaluation and characterisation of olive pulp as a feed ingredient for dairy goats

Abstract

The utilization of agri-food by-products in animal nutrition presents an opportunity for the transition to a bioeconomy. In Spain, the olive industry generates about 612,000 tonnes/year of by-products, primarily olive pulp (OP), whose characteristics and composition allow it to be frequently used as biomass for energy production or as an ingredient for obtaining pomace oil, among others. However, its use in the animal nutrition sector is not completely defined, since it is an element that depends on conjunctural factors such as variations in olive harvest and the volatility of animal feed and energy prices. This study evaluated the nutritional value of an OP variant (partially destoned and dehydrated, but without re-extraction) by analyzing its nutritional composition and conducting in vitro cultures of ruminal microorganisms to examine the ruminal fermentation (RF) of both OP compared to other raw materials commonly used in ruminant feed formulation, and different incorporation proportions of OP in a commercial feed. Despite OP's limited capacity to provide nutrients due to its high lignin content and low digestible protein, it stood out for its fat content and composition. The absence of negative effects on FR indicated the viability of its use in ruminant nutrition up to 15% inclusion.