Effects Of Three Additives On Freezing Characteristics And Nutrient Degradation Rate Of Fermented Feed

Due to the high water content of fermented feed,it is generally more than 30%,that is to say,the feed is in a humid state,which is easy to freeze and block when the temperature is low,affecting the taste of animals.Moreover,eating frozen and caked feed in winter is easy to burden the intestines and stomach of animals and increase the possibility of animal diseases.In view of the above problems,it is urgent to study the antifreeze and its application in fermented feed.This experiment is divided into two parts.Experiment 1: This experiment studied the freezing curve of fermented feed after adding three additives(chitosan,calcium formate and trehalose)and their effects on the freezing point of fermented feed and the survival rate of lactic acid bacteria,so as to screen out the addition level of each additive with better frost resistance in fermented feed.The concentration of chitosan is set at six levels of 0.05%,0.1%,0.15%,0.2%,0.25% and 0.35,the concentration of calcium formate is set at seven levels of 0.5%,1%,1.5%,2%,2.5%,3%and 3.5%,and the concentration of trehalose is set at five levels of 0.5%,1%,1.5%,2% and2.5%.Six replicates are set at each level of the three additives.The results showed that:(1)chitosan,calcium formate and trehalose could reduce the freezing point of fermented feed and improve the survival rate of lactic acid bacteria in fermented feed;(2)From the data obtained from this experiment and combined with the actual situation,it is more suitable when the addition amount of chitosan is 0.25%,the addition amount of calcium formate is 3% or the addition amount of trehalose is 2%.Experiment 2: Single factor four level analysis of variance was used in this experiment,the additive concentration(0.25% chitosan,3% calcium formate and 2% trehalose)selected from Experiment 1 was studied.The degradation rate of DM and fiber in fermented feed was determined by ankom simulated nylon bag digestion outside the culture box.The results showed that:(1)0.25% chitosan significantly increased the degradation rate of DM at3 H and 12 h,NDF at 3h,6h and 36 h,and ADF at 6h and 36 h.(2)3% calcium formate significantly increased the degradation rate of DM and NDF at 3h,12 h and 24 h.(3)2%trehalose significantly increased DM degradation rate at 3H and 12 h,DM degradation rate at6 h,and NDF degradation rate at 3h and 6h.(4)Among the three additives,calcium formate has the best anti freezing effect on fermented feed.Conclusions:(1)chitosan,calcium formate and trehalose can reduce the freezing point of fermented feed and improve the survival rate of lactic acid bacteria in fermented feed.(2)0.25%chitosan,3% calcium formate and 2% trehalose could significantly improve the degradation rates of DM,NDF and ADF in fermented feed.