Study On Fermenting Wheat Distiller’s Grains Technology And Evaluation On Its Nutritive Value For Growing Pigs

The process of producing alcohol in wheat produce amount of distillers grains,which has a high content of crude protein and rich nutrients.But moisture content is high and it is easy deterioration.Therefore,the traditional method is to dry and produce wheat DDG as feed.However,high temperature drying is not only high in energy consumption but also denaturation of proteins and reduce feeding quality.Direct feeding of wheat distiller’s grains by solid-state fermentation using microorganism is not only save high cost of drying but can improve feeding quality.Therefore,this study first optimized the process of solid-state anaerobic fermentation of wheat distiller’s grains,and then evaluated the nutritional value of their feeding growth pigs,in order to provide scientific basis for the application of fermented wheat distillers’grain in pig diets.This study was separated 2 parts:Part 1:Screening of fermentation strains for wheat distiller’s grain and optimization of fermentation conditions.16 strains of feeding microorganisms preserved in laboratory were selected.Wheat distiller’s grain was used as raw material,supplementary powder,and the content of acid soluble protein in fermentation product was the main evaluation index.Firstly,single factor experiment was used to choose the optimal strains to select the best combination,then optimize fermentation substrate,inoculum volume,fermentation temperature,and fermentation time.On the basis of single factor experiment,solid-state fermentation conditions(inoculation volume,fermentation temperature,and fermentation time)were optimized by the response surface.The results showed that it is preferably in the fermented substrate of 38%wheat dried distiller’s grain and 62%wheat middlings,1:1 ratio of Lactobacillus R-O2 and Bacillus KG-109 concentration were 1.22%,and fermentation temperature at 33.45℃ for 6.67 days.Acid soluble protein increased from 0.74%to 4.33%(P<0.05).The pH value decreased from 5.38 to 3.98(P<0.05).The number of probiotics increased from 6.9×107 cfu/g to 5.5×109 cfu/g(P<0.05).Protease activity increased from 72.1 U/g to 196.14 U/g(P<0.05).Part 2:The nutritive value of fermented wheat distiller’s grain fed growth pigs was evaluated.The aim of this study was to evaluate nutritional value of fermented wheat distiller’s grain.The experiment chose four barrows,with an initial BW of 35± 1 kg.The T-cannulas was installed at the end of ileum to measure the digestive energy,metabolic energy,apparent digestibility of nutrients,and true digestibility of the amino acids of fermented wheat distiller’s grain in three phases.There were three kinds of diet:first kind was basal diet for growing pig of commodity pellet compound feed,second kind was mixed diet consisting of 30%fermented wheat distiller’s grain and 70%basal diet.Third kind was casein diet prepared formulated with casein as the sole protein source.The results showed the apparent digestibility of dry matter,crude protein,crude fat,crude fibe,calcium,and total phosphorus of fermented wheat distiller’s grain were 76.40%,74.21%,58.44%,31.48%,48.08%,and 51.87%,respectively.The contents of digestible energy and metabolizable energy were 12.42 MJ/kg and 11.96 MJ/kg,respectively.The apparent digestibility of arginine,lysine and methionine were 90.32%,85.83%,and 92.63%,respectively.Conclusion,fermented wheat dried distiller’s grain was a good quality protein feed.