تاثیر واریته و میزان تفت دادن بر ترکیب شیمیایی و فراسنجه های تخمیری و فیزیکی دانه جو با استفاده از روش تولید گاز

Background:chemical composition and heat processing extent can affects fermentabality of barley grain. objectives:the examination was conducted to investigate the effects of different time of roasting (5, 10 or 15 min at 120oc) and variety of barley grain (sahand and makouyi) on nutritive value and correlation between its parameter with bulk density using in vitro gas production techniques.methods:the data was analyzed using factorial completely randomized design. results:the result show that heat treatment decreased the degradation of dm in each variety. gas production of soluble and in soluble fraction)a) and rapid of degradation decreased by increasing time of roasting. the obtained data from gas production at 24 h after incubation were used for estimation of metabolazable energy (me), net energy for lactation (nel), short chain fatty acids (scfa) and digestible organic matter (dom). estimated parameters of gas production were affected by variety and heat treatment. metabolizable energy decreased by increasing time of roasting from 9.40 to 8.29 and 9.61 to 8.77 at sahand and makoei variety respectively. correlation between metabolizable energy, net energy for lactation, short chain fatty acids and digestible organic matter by bd50 was positive (r2=0.53, r2=0.52, r2=0.58 and r2=0.52respectively). conclusions:results of this research showed that roasting process can be used effectively the same as other conventional heat treatment methods for decreasing degradability of dry matter in rumen and increasing digestible escaped dry matter resulting improved rumen ecosystem and decreased acidosis due to decreasing of rate of fermentation.