Quality Evaluation And Influence On Nitrogen Metabolism In Sheep Of Starea

After the expanding treatment with mixture containing 65% of maize , 20% of urea , 15% mineral substance carrier under 80℃,100℃,120℃,140℃, four starea samples with 56.23%, 68.39%,78.42% and 80.24% of degree of gelatinization were obtained. The simple and feasible evaluation methods and selection of starea product with slow release capability were studied by the measurations of urea solubility and NH₃ release quantity in vitro,DM disappearance rate and protein degradability in sacco technique,NH₃ release quantity in vivo. Then TMR adding starea was designed,the researchs of the effect on ferment concentration in the rumen , blood biochemical parameters, nitrogen metabolism in sheep were carried out, which provided scientific basis for the quality standard of application and starea product.Test 1: The urea solubility of four different starea products were measured in 37℃ water for 20min,40min,60min,80min,100min,120min. The result indicated, the urea solubility increased as time went on and decreased with the increasing of gelatinization. The urea solubilities at 60min were 81.14%, 70.52%, 64.58% and 60.15% respectively. The relation between urea solubility and gelatinization at 60min was: y= -0.8152x+126.83(R²=0.9802,n=4).y: urea solubility(%). x: degree of gelatinization (%).Test 2: The mensuration result of NH₃-N in vitro indicated, the change of NH₃-N releasing quantity and urea solubility of four starea products was basically consistent. The relation between urea solubility and NH₃-N releasing quantity at 60min was : y =4 6567x+61.149(R² =0.9821,n =4). y: NH₃-N releasing quantity (%). x: urea solubility (%).Test 3: 15 sheep with permanent rumen cannula were divide 5 group randomly. The slow release effect of starea was evaluated in sacco technique in contrast with control group. The result indicated, the DM disappearance rate and protein degradability at 60min of group 4 decreased for 51.24%,50.49%,43.95%(p<0.05)and 36.36%,38.90%,26.91%(p<0.05)respectively in contrast with control group, group1 and group 2. The relation between urea solubility and the DM disappearance rate,protein degradability at 60min was:y₁=0.8932x -37.777(R²=0.8619,n=4),y₂=1.1769 x -29.86(R²=0.9877,n=4),y₁:DM disappearance rate(%),y₂:protein degradability(%),x:urea solubility(%).Test 4: The means of NH₃-N concentration in rumen of four sterea products of 4h decreased for 14.10%, 17.61%, 25.82% and 28.85% respectively in contrast with control group. The NH₃-N concentrations in rumen of group3 and group 4 were distinctly influenced in contrast with other groups(p<0.05). The relation between urea solubility and NH₃-N concentrations in rumen at 60min was: y=0.2387x+19.012,(R²=0.9696,n=4)。 y: NH₃-N concentration (mg/100ml),x: urea solubility (%). Test 5: 12 sheep with permanent rumen cannula were divided 3 groups at random. TMR withnitrogen existing as 1% of urea and 5% of starea respectively were fed to sheep equivalently in place of soybean meal. The results indicated: NH3-N,Urea-N and Total-N concentrations in rumen of TMR of starea decreased for 29.90%, 42.94%, 14.15%(p<0.01)in contrast with TMR of urea, and was close to the grain level of TMR of soybean meal with the extension of time points (p> 0. 05).Test 6: The blood biochemical parameters of sheep fed with 3 different TMR were not distinctly influenced and were in normal range(p>0.05). Concentrations of BUN, CRE, GGT of TMR revealed the decreasing trend, ALP increasing trend, AST unobvious change.Test 7: The effect of 3 TMR on sheep was measured by the method of normal metabolism test. The result indicated, DM intake, nitrogen intake, feces nitrogen, absorbed nitrogen, DM digestibility, N digestibility of all groups were not distinctly influenced(p>0.05). Metabolized nitrogen, metabolized nitrogen rate ,metabolized nitrogen/absorbed nitrogen of TMR of starea group increased for 43.86%> 42.64%, 45.32%(p<0.05)in contrast with TMR of urea group respectively. TMR of starea group were not distinctly influnced in contrast with TMR of soybean meal group(p>0.05)...