| Soybean dregs is a kind of by-product extracted in the processing soybean oil, soy sauce, tofu and other soy products. But due to the rough texture and low heat energy, soybean dregs has not been paid attention for a long time. Therefore, The objective of this study was to use soybean dregs as raw materials and transform them into a ruminant feed with good palatability and resistant storage by solid-state fermentation of mixed bacteria. Bacillus subtilis and Lactic acid bacteria were used as fermentation bacteria to ferment the soybean dregs, then the composition of fermentation substrates, the ratio of inoculating bacteria, the quantity of inoculation and the temperature of fermentation were confirmed by L9(34) orthogonal test. The aim of this study was to obtain a ruminant feed with low p H, good palatability, smell and resistant storage, which improving nutrient utilization on the basis of retaining the nutrients of original soybean dregs. The fermentation quality, nutritional value and ruminal degradation parameters of fermentation products were detected. The specific experiments were as follows.Experiment Ⅰ: Optimization of fermentation conditions of soybean dregsIn this experiment, the L9(34) orthogonal test was used to choose the composition of fermentation stuff(9: 1,8: 2,7: 3), the ratio of inoculating bacteria(1: 1,2: 1,5: 1),the quantity of inoculation(5%, 10%, 15%) and the temperature of fermentation(33 ℃, 35 ℃, 37 ℃). The effects of four factors on fermentation quality were evaluated by using the laboratory comprehensive scoring method. The results showed that the best ratio of craft condition: wheat bran was 7:3, Lactic acid bacteria: Bacillus subtilis= 1:1, quantity of inoculation was 5% and optimal temperature was 35℃.At the same time, the secondary fermentation of fermented products was investigated by testing the temperature of fermented soybean dregs after opening the bag. The results indicated that adding mixed Lactic acid bacteria and Bacillus subtilis into soybean dregs could effectively improve aerobic stability of soybean dregs.Experiment II: Determination of the fermentation product quality assessment and conventional fermentation nutrients before and after the optimal ferme ntation.In this experiment, the soybean dregs were fermented under the optimum fermentation conditions. Fermentation products were evaluated by the laboratory integrated score and nutrition value measured by laboratory conventional methods.The results showed that the optimum fermentation conditions determined by test I were feasible, and the fermentation products were belong to superior grade, while p H value was 4.08. With p H decreased, disadvantage microorganisms growth in fermentation products were inhi bited. The results conformed with the purpose and requirements of experimental. After fermentation, the content of CP increased from 25.29% to 33.81%, while NDF, ADF, EE, and WSC were decreased, especially NDF, fell to 28.33% from 35.10%.Experiment Ⅲ: evaluation of fermentation product ruminal degradation parametersThe aim of this study were to assess the nutritional value of fermented feed by comparing degradation characteristics before and after fermentation. The DM, CP, NDF degradation characteristics and parameters(a, b, c) of Fermentation material and product were determined by nylon bag technique.The results showed that compared to the fermentation raw material, DM, NDF and CP ruminal degradation of fermentation product increased in 72 h, rapidly degraded part and effective degradable rate of dry matter were significant higher( p < 0.05), while the DM potentially degradable part(a + b) of fermentation raw material were significant higher than fermented soybean dregs(p <0.05); rapidly degraded part and effective degradable rate of crude protein were significant higher than fermentation raw material(p <0.05). The effective degradation rate of NDF were significant higher than fermentation raw material(p <0.05).In conclusion, the comprehensive fermentation quality score, p H, aerobic stability, conventional nutrition component analysis and ruminal degradation parameters of soybean dregs after solid state fermentation by mixed bacteria showed that fermented bean dregs was a kind of ruminant protein feed with the advantages of safe, low p H, shelf stable. It provides a preliminary theoretical basis that fermented bean dregs could been applied to ruminant actual production. |
PDF Full Text Request