Study On The Technology Of Pig Feed Production With Brewers' Spent Grain

Brewers'spent grains(BSG) is the largest brewing by-products. In this paper,pig feed were selected as the object of study for BSG,pre-treatment techniques,including enzymolysis and fermentation technologies were used to degrade BSG fiber and improve the protein quality for improving the feeding value of BSG. The content of protein, fiber and nutrition of BSG were determined. The results showed that the fiber of BSG consisted of crude fiber and neutral detergent fiber(NDF) ,and their content are 13.4% and 49.2%,respectively; crude protein was about 29%,and the true protein content accounted for 88% of crude protein content ,which will contribute to develop high-quality protein feed ,BSG can be developed as pig feed with a high added value .Pre-treatment methods such as steam-explosion,ultra-fine pulverization, cellulase hydrolysis for BSG were investigated,and a series of parameters were analyzed,such as fiber structure,fiber complex,and reducing sugar. In comparison with pretreatment taken before and after, the steam-explosion technique can destroy fiber structure,decrease NDF content,and increase reducing sugar content.The optimization of cellulase hydrolysis of BSG were as follows,enzyme concentration 180U / g,substrate concentration 10%, temperature 50℃,cellulase hydrolysis time 6h .The content of increasing of reducing sugar amounted to 12.77mg/mL by the treatments with both steam-explosion and cellulase hydrolysis,however,the content of NDF had no change. the optimum fermentation conditions : BSG-water ratio 1:1,fermentation agent 50g/40kg BSG,enzyme 50g / 40kg BSG,fermentation temperature 25 ~ 37℃, fermentation time 7 days or so after a preliminary study on the BSG fermentation conditions and effects; compared with the control,the combination of steam explosion pretreatment and add the enzyme was best, the NDF of BSG degraded from 67.8% to 35.6%, Degradation rate is 47.5%,The effect of fiber degradation is very obvious; soluble nitrogen increased from the 35.3mg/L to 617.2mg/L,an increase of 16 times. After fermentation,amino acids were more comprehensive,content higher,brewer's grain nutrition level is more balanced.By feeding experiment for fattening pig,the results showed that the content of fermented BSG can reach 26.1%,All of the growth properties,the feed intake and the average weight of fattening pig had no significant differences in different period. The feed conversion rate of fermented BSG was lower than control,The costs of gaining weight for per kilogram decreased 1.055 yuan comparing with control.