IN SITU RUMEN DEGRADABILITY AND INTESTINAL DIGESTIBILITY OF TWO DIFFERENT TYPES OF RAPESEED MEAL

The rumen degradability and intestinal digestibility of rapeseed meal (RSM) produced in Bulgaria (Astra Bioplant Ltd., Slivo pole, Rousse district) and in Romania (Expur Ltd., Slobozia) was determined. Three non-lactating Jersey cows with a body weight of 436 ± 18 kg, fi tted with rumen fi stula and T-duodenal cannula were used. Three batches from each factory were taken in interval of 20 – 30 days in Bulgaria (RSMb-1, RSMb-2, RSMb-3) and in Romania (RSMr-1, RSMr-2, RSMr3). RSM were incubated in the rumen for 0, 2, 4, 8, 16, 24 and 48 h in 6 replications. The effective degradability of DM was signifi cantly lower for RSMr-3 compared to other samples (P<0.05). The results for rapidly degradable fraction a of CP for all the batches of Bulgarian RSM (26 to 30%) were signifi cantly higher than those of Romanian RSM (P<0.05). The values for potentially degradable CP fraction b varied between 66% and 73% without any signifi cant differences for either factories or batches (P>0.05). The effective degradability of CP at different outfl ow rates (k=0.045; 0.06; 0.08) for all the batches of Bulgarian RSM were approximately 4% higher than those for Romanian batches (P<0.05). The intestinal digestibility of DM determined by mobile bag technique was higher for RSMb-3 compared to other batches of RSM (P<0.05). The values for intestinal digestibility of CP varied between 74% (RSMr-1) and 80% (RSMb-2) without any signifi cant differences (P>0.05). The protein digestible in intestine (PDI) at outfl ow rate 0.06/h according to Bulgarian feed evaluation system was 165 g/kg DM for RSMb and 171 g/kg DM for RSMr. The protein balance in the rumen (PBR) of RSM was 111 and 82 g/kg DM, respectively. There is room for improvements of protein nutritive values especially for Bulgarian RSM by improving the toasting process. The protein nutritional values reported in the present experiment could be used instead of the data published abroad for RSM.