Nutritive value of two types of olive cake (Olea europaea l.) for growing rabbit

Abstract

The nutritive value of 2 types of sun-dried olive cake (OC), extracted traditionally (COC) or with a 3-phase olive cake (TPOC), was studied for the growing rabbit. Four diets containing 10 or 20% of COC (COC10 and COC20) or of TPOC (TPOC10 and TPOC20) in substitution for a basal diet were compared to a control diet without OC (OC0). Five groups of 12 rabbits were fed one of the 5 diets ad libitum from weaning (35 d) to 46 d of age. The faecal digestibility was individually measured between 42 and 46 d of age. COC and TPOC are high fibre and lignin sources, with 707 and 787 g/kg dry matter (DM) of neutral detergent fibre, 530 and 554 g/kg DM of acid detergent fibre, 242 and 243 g/kg DM of acid detergent lignin, respectively. Replacing 20% of basal diet by COC sharply reduced (P<0.001) the digestibility of energy and crude protein from 0.67 to 0.54, but that of protein only moderately (from 0.80 to 0.76). The same effect was observed with the incorporation of 20% of TPOC. The digestible energy (DE) content of COC and TPOC were calculated by regression and were 3.24±0.41 and 2.94±0.52 MJ DE/kg DM respectively, corresponding to an apparent faecal digestibility of the gross energy of 0.14 (COC) and 0.13 (TPOC). The apparent faecal digestibility of the crude protein of COC was 7 units higher than TPOC (0.44 vs. 0.37) and the digestible protein (DP) content was 20% higher (27.9±4.2 g vs.22.4±6 g DP/kg DM). Olive cake could be considered as a high fibre source with a low protein and energy content for the growing rabbit.