Study On Solid State Anaerobic Fermentation Of Rapeseed Meal

With 7.8 million tons annual output of rapeseed meal. China occupies the first place in the world. Rapeseed meal is an important vegetality feeding protein with high content of crude protein (35%~40%) and a large quantity of amino acid, only lysine is lower than that of soybean meal. Rapeseed meal also have plenty of anti-nutritional factors, such as glucosinolates, phytic acid, sinapine, phenolic acid, tannin etc. These anti-nutritional factors have some negative influences to animals.For instance, affecting the palatability, reducing the feed intake, decreasing the effective availability of nutritional components, especially glucosinolates and its decomposed products which have toxicity. As animals'diets with high content glucosinolates, they will be caused by toxicity response, such as thyroid, liver, renal's function decreasing, or even led to death. Microbiological fermentation is an effective method in the detoxification of rapeseed meal. At present, the fermented rapeseed meal often using aerobic microbe in the fermentation process, but rapeseed meal nutrient substances in the aerobic fermentation process were serious loss, and the palatability of fermented rapeseed meal is poor, meanwhile, the fermentation process usually cause sundry bacteria contamination too. Researches on using the anaerobic microbe in rapeseed meal fermentation process are related less. This study was carried out by mixed bacteria anaerobic fermentation technology using two strains of Laobacillus plantarum R-02 and Bacillus subtilis KGC30141. Taking the contents of glucosinolates in the fermented rapeseed meal for the main outcome measure, the experiment optimizes the anaerobic fermentation conditions by orthogonal experimental design. Then, by using nitrogen ion beam implanted mutagenesis technology to explore the mutagenic improvement of Laobacillus plantarum R-02, for the purpose of obtaining some superior mutant strains which can degrade glucosinolates more efficiency. Finally, using a digestion and metabolism experiment on fattening pigs to evaluate the fermented rapeseed meal's feeding value.Experiment 1: The study on optimization of rapeseed meal anaerobic fermentation conditions. The fermented rapeseed meal was produced by mixed strains (Laobacillus plantarum R-02 and Bacillus subtilis KGC30141) through solid state anaerobic fermentation. The effects of the inoculation amount of two strains, the adding proportion of corn-steep liquor and glucose, and environmental temperature on the content of glucosinolates and crude protein, the loss of materials in fermented rapeseed meal were researched and optimized by a L18(35)orthogonal experiment. Results show the optimization conditions were as follows: the ratio of inoculation quantity of Laobacillus plantarum and Bacillus subtilis was 6%:15%, corn-steep liquor 20%, glucose 3%, environmental temperature 28℃, material to water ratio 1:1, with the 15-day anaerobic fermentation, the glucosinolates content in the fermented rapeseed meal decreased from 83.90μmol/g(d.b.) to 33.04μmol/g(d.b.),with the degradation of 60.62%, and the crude protein increased by 4.15% compared to original, the loss of materials was 3.73%.Experiment 2: Study on the mutagenesis of Laobacillus plantarum R-02 by nitrogen ion beam implant technology. Nitrogen ion beam implanted mutagenesis technology was used to mutate Laobacillus plantarum R-02 with the implantation dosage of (10,20,30,40,60,80)×2.5×013 N+/cm2 and under the implantation energy of 20KeV. Taking the contents of glucosinolates in the rapeseed meal fermented by mutant strains for the main measure to select and breed superior strains. It was shown that the mutant strain numbered 4# under the dose of 10×2.5×1013 N+/cm2 had high fermentation performance and with the rate of glucosinolate degradation raised 7.85 percent points compared to original strain.And the single-strain fermentation performance with 5 generation cultivation of 4# was stable (p>0.05). Meanwhile, the multi-strain fermentation performance of 4#( combined with Bacillus subtilis KGC30141) improved obviously,and with the glucosinolate degradation rate increased by 13.69 percent points compared to that of original strain.Experiment 3: Study on the feeding value of fermented rapeseed meal on fattening pigs. Three Duroc×Landrance×Yorkshire fattening pigs with body weight of 55.0(±1.5)Kg were selected to study the digestibility of fermented rapeseed meal. In the feeding period ,the three experimental pigs were fed N-free diet and semi-purified diets with common rapeseed meal,dry fermented rapeseed meal and wet fermented rapeseed meal as only protein source, respectively.The digestibility of crude protein and the digestibility of dry matter on fattening pigs were determined by the N-free diet method and the total feces collection method.The results show that the apparent digestibility and the true digestibility of crude protein in fermented rapeseed meal were higher than that of common rapeseed meal(p<0.01), and the differences between the two fermented rapeseed meals were not significant(p>0.05). meanwhile, the apparent digestibility of the dry matter in fermented rapeseed meal diets were significant higher than that of common rapeseed meal diet(p<0.01). Compared with common rapeseed meal, solid state anaerobic fermented rapeseed meal could significantly improve the nutritive property and nutrient digestibility...