Effects Of Pelleting Process Parameters On Physical Quality Of Pelleted Brown Rice Pig Feed

Three experiments were conducted to investigate the optimal processing parametersof brown rice to substitute for corn as energy feed and provide technical support for cruderice-type feed production. Experiment One was conducted to formulate a regressionmathematical model among feed productivity, percentage of powdered pellets, hardness andgelatinization degree for crude rice-type ration, Experiment Two was designed to investigatethe range of steam pressure, steam addition and feeding speed when steam condition wasgiven to produce the crude rice-type ration. Experiment Three was conducted to investigatethe optimal crude rice to maize ratio when no steam condition was given in crude rice-typeration.Experiment One: Effect of main processing parameters on technical performance ofcrude rice-type feedAccording to NRC, A growing pig ration was formulated, and a single factorexperimental design was conducted. Three factors such as steam pressure, steam additionand feeding speed were considered. Dry-saturated steam condition was used to determinethe range of each parameter. The results showed that the optimal parameters were as follows:steam pressure: 0.2Mpa-0.4Mpa; steam addition: 3%-6%; the feeding speed: 40-160 kg h^-1.Experiment Two: The effect of pelleting process parameter on physical quality ofpelleted brown rice-type pig feedAccording to the range determined in Experiment Two, three factors (steam pressure,steam addition and the feeding speed)×five levels orthogonal rotatory combination designwas conducted using dry-saturated steam condition, then pelleted to set up a mathematicalmodel according to the experimental data, then the model was used to analyze the effects ofthe three factors on experimental indices, predict or control the produce processing andascertain the optimal technical parameters. The date showed that the significance of theregression mathematical model obtained among productivity, percentage of powdered pellets,hardness and gelatinization degree amounted up to 95%, the optimal technical parametersafter optimizing were as follows: steam pressure: 0.39Mpa; steam addition: 3%; feedingspeed: 130 kg h^-1.Experiment Three: Substitute rate of crude rice for corn as energy feedSix experimental diets, were formulated to examine the effect of the ratio of replacingcorn with brown rice on the physical quality of pellets:Ⅰ(100% corn; the control),Ⅱ(75%corn plus 25% brown rice),Ⅲ(50% corn plus 50% brown rice),Ⅳ(25% corn plus 75%brown rice),Ⅴ(100% brown rice plus 2% plant oil) andⅥ(100% brown rice plus 3% plant oil). Yield, density, bulk density, stability in water, hardness and percentage of powderedpellets of every pellet feed were measured. Compared with the control, as the ratio of brownrice increased, the productivity, stability in water and hardness was improved(p＜0.01) whilethere was no change in density and bulk density(P＞0.05).According to the above experiments, steam pressure, steam addition and feeding speedaffect the physical quality of the crude rice-type ration to some extent. Under thisexperimental condition, the optimum processing parameters of crude rice ration were asfollows: steam pressure: 0.39 MPa; steam addition: 3%; feeding speed: 130 kg h^-1.During pelleting, the replacing of brown rice for corn can lengthen the stabilityin water of the pelleted feed, raise the hardness and lower the percentage ofpowdered pellets, so it can improve the physical quality of the pelleted feed. Whenreplacing ratio of brown rice to corn was considered, the ratio should be lowerthan 75%, or the productivity will be lowered, but oil addition can compensate tosome extent.