| This study was proposed to investigate the associative effects between mulberry leaves (ML) and oil-seed-meal (OSM) after they were incubated in vitro rumen fluid by the determination of gas production and microbial protein and to examine the probable mechanism of forming associative effects in ruminants.Mulberry leaves were mixed with rapeseed meal (RSM),soybean meal (SBM) or cotton-seed meal (CSM) at the proportion of 0,20,40,50,60,80,100% in the mixtures,respectively(trial 1). The mixtures of ML with oil-seed meal (OSM) were incubated in vitro rumen fluid for 96h twice. Gas productons (GP) were determined at 0,2,4,6,9,12,16,24,36,48,72,96h of incubation,and estimation was made on the parameters of GP,digestibility of organic matter (OMD) and partitioning factor (PF). The associative effect (AE) between ML and OSM was estimated according to the GP,OMD as scale. When RSM at the proportion of 40,50,60,80 % in mixture,the AE between ML and RSM were respectively -3.5(p<0.05),-3.17 (p<0.05),-6.0 (p<0.05),-7.3 (p<0.01) according to the scale of GP,and -1.1,-0.8,-1.7 (p<0.05),-1.9 (p<0.05) according to the scale of OMD. AE between ML and SBM were respectively -5.2 (p<0.01),-3.6,-2.2,-3.6 (p<0.05) on the GP for the proportion of 20,40,50,80 of SBM in the mixtures,and corresponding -2.0 (p<0.01),-1.3,-0.8,-1.5 (p<0.05) on the OMD. When CSM in the mixtures at the levels of 20,50,60,80%,the AE on GP attained -1.5 (p<0.05),-1.5,-7.0 (p<0.01),-5.6 (p<0.05),respectively;AE on OMD reached -0.5,-0.5,-2.0(p<0.01),-1.2 (p<0.05),respectively. Those results indicate that negative associative effects occur between ML and RSM,SBM,or CSM when three kinds of OSM are mixed with OSM at the proportion of 60 and 80% according to the scale of the GP and OMD.Mulberry leaves were mixed with rapeseed meal (RSM),soybean meal (SBM) or cotton-seed meal (CSM) at the proportion of 0,20,40,50,60,80,100% in the mixtures,respectively(trial 2). The mixtures of ML with oil-seed meal (OSM) were incubated in vitro rumen fluid for 48h. Microbial protein (MP) production in rumen fluid was determined by purine analysis,and AE between ML and OSM was estimated according to the MP as scale. Determination of NHs-N concentration in rumen fluid at 24h of incubation by colorimetry analysis and pH value in rumen fluid at 24,36,48h of incubation by pH meter were conducted. When at the proportion of 40,50,60,80% of OSM in mixture,AE between ML and RSM were respectively 1.1,-1.8,-1.1,-1.5,that between ML and SBM were respectively -3.3,-2.1,1.8,2.5,-1.3,and that between ML and CSM attained -1.2,-2.5,0.7,-0.6 according to the scale of MP. Those results indicate that negative associative effects occur between ML and RSM,SBM,or CSM when three kinds of OSM are mixed with OSM at the proportion of 60 and 80% according to the scale of the MP.There were inconsistent results between associative effects on gas production and that on microbial protein. It is necessary to combine GP with MP when evalution of AE between ML and OSM. The synthetical associative effect (AEs) as a scale based on GP with MP of feeds had been constructed in this study. When the proportion of 20,40,50,60,80% of OSM in the mixtures,AEs between ML and RSM attained -1.0,-1.7,-2.0,-3.5,-3.9,that between ML and SBM were -4.6,-3.2,-0.9,-0.9,-3.1,and that between ML with CSM attained -1.5,-1.1,-0.6,-4.3,-1.7,respectively. It is probably more reasonable to evaluate the AE between feedstuff's according to the scale of AEs,for AE values on AEs intermediate between those on GP and on MP,and the tendency in the result on AEs looked more regular.The mixtures of mulberry leaves with rapeseed meal at the proportion of 0,60,80,100% of rapeseed meal were supplemented to the experimental diets as protein concentrate (trial 3). The diets included 50% Chinese Aneurolepidum,25% corn grain and 25% protein concentrate. The mixtures of ML with oil-seed meal (OSM) were incubated in vitro rumen fluid for 72h twice. In vitro protein degradability (IVPD) for the diets was estimated by determination of gas produ... |
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