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

Gancho Ganchev, Miroslav Simeonov, Krum Nedelkov, Dimo Girginov, Nikolai Todorov

Abstract: 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 fistula 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, RSMr-3). 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 significantly 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 significantly higher than those of Romanian RSM (P<0.05). The values for potentially degradable CP fraction b varied between 66% and 73% without any significant differences for either factories or batches (P>0.05). The effective degradability of CP at different outflow 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 significant differences (P>0.05). The protein digestible in intestine (PDI) at outflow 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.

Keywords: intestinal digestibility; protein nutritional value; rapeseed meal; rumen degradability

Date published: 2017-07-07