Chemical composition and nutrients availability for goats and sheep of two-stage olive cake and olive leaves

Abstract

The chemical composition and the in vitro and in situ availability of nutrients for goats and sheep have been determined in the two stage dried olive cake (TSDOC) and the olive leaves (OL). Additionally, the composition of undegraded protein after incubation for 16 h in the rumen of goats and sheep and the degradation of individual amino acids have been determined. Both by-products are rich in cell walls (62.4 and 41.3 g NDF/100 g DM, respectively, in TSDOC and OL) and poor in CP (78.8 and 70.0 g/kg DM, respectively, in TSDOC and OL) being a great part of the N attached to the lignocellulosic fraction (706 and 533 g ADFN/kg total N, respectively, in TSDOC and OL). Essential amino acids showed similar values in the two by-products (552 and 543 g AA-N/kg total N, respectively, in TSDOC and OL). TSDOC and OL are rich in gross energy (18.7 and 16.8 MJ/kg DM, respectively) and in phenolic compounds being values of tannins higher in TSDOC than in OL (13.8 and 8.30 g/kg DM, respectively). In vitro digestibility either of TSDOC and OL showed low values, especially for CP (96.2 and 124 g/kg, respectively) the lowest value being for TSDOC with rumen liquor from sheep. Potential degradability was lower in TSDOC than in OL (449.5 g versus 745 g DM/kg and 554.5 g versus 701.5 g CP/kg). Effective degradability was also lower in TSDOC than in OL (410.5 g versus 535.5 g DM/kg and 434 g versus 458.5 g CP/kg). The animal species did not significantly ( P>0.05) affect neither the total N and individual amino acidic nitrogen nor the degradability of total and individual amino acids. On the contrary, the type of by-product determined significant differences in all those parameters. Important differences were observed between the composition of original and rumen undegraded protein. The degradability of total N was lower than most of the individual amino acid in rumen undegraded protein from TSDOC and OL.