This experiment was conducted to study the effects of different proportions of sorghum replacing corn and conditioning temperature on the forming rate,hardness,pellet durability index,starch gelatinization degree and color of the pellet feed.Based on the typical corn-soybean meal diet for broilers,sorghum was used to replace corn with substitution mass fraction of 0％,20％,40％,60％,80％and 100％,respectively.The gelatinization charac-teristics and thermal characteristics of the six groups of materials were determined and analyzed.The conditioning temperature was 75 ℃ and 85 ℃,respectively.The pelleting characteristics and processing quality of each group of pellet feed were measured.The results indicated that:1)In terms of the basic physical and chemical properties of the mash,with the increase of sorghum substitution ratio,the peak viscosity and final viscosity showed a significant downward trend,and the pasting temperature,peak temperature and enthalpy change of gelatinization showed a sig-nificant upward trend(P＜0.05).2)In terms of pellet feed quality,with the increase of sorghum substitution ratio,the forming rate of pellet feed showed an overall upward trend,and the hardness of pellet feed showed a trend of de-creasing firstly and then increasing,however,the difference was not significant(P＞0.05).The pellet durability in-dex showed a significant upward trend,the starch gelatinization degree showed a significant downward trend,and the values of L,a and b showed a significant downward trend(P＜0.05).With the increase of conditioning tempera-ture,the forming rate of pellet feed did not change significantly(P＞0.05).The hardness of pellet feed showed a significant downward trend,the pellet durability index and starch gelatinization degree showed a significant upward trend,and the values of L,a and b showed a significant upward trend(P＜0.05);there were significant interactions between sorghum substitution ratio and conditioning temperature on the hardness,starch gelatinization degree,values of L,a and b of pellet feed(P＜0.05).In summary,the proportion of sorghum replacing corn had little effect on the pellet feed,and the quality of pellet feed in each group meet the standard requirements.The effect of conditioning temperature on pellet feed was significant,and it was recommended to use the conditioning temperature of 85℃for the diet supplemented with sorghum.
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