Fermentation Of Tea Seed Meal With Rumen Microbes To Produce High Protein Feed

Tea seed meal is the residue of camellia seed after the oil is extracted. It containstea saponin, protein, polysaccharide and other useful components, which could befurther utilization to achieve maximum economic value. This study explored thefeasibility of producing high-protein feed by anaerobic fermentation of tea seed mealusing the ruminal contents as microbial inoculums.1. Optimization of anaerobic fermentation conditions. A L9(33) orthogonalexperiment was carried out to investigate and optimize factors, such as the inoculumsize of ruminal contents, the additive amount of non-protein nitrogen (NPN)(urea+ammonium sulfate) and the ratio of dried tea seed meal to water on the outcomes ofanaerobic fermentation. The content of total soluble sugar, true protein, crude fiberand tea saponin were used as the evaluation index. The results showed that differentmeasurement indexes led to different optimal proportion. All conditions wereconsidered that the optimized conditions were as follows: urea and ammonium sulfatein non-protein was1.0%and1.5%, respectively, the inoculation amount of ruminalcontents was10%and the ratio of dried tea seed meal to water was1:0.5.2. After anaerobic fermentation of tea seed meal for3days using theoptimization conditions, yeast (Saccharomyces cerevisiae) was added for further fermentation under aerobic condition. The yeast inoculation size and the fermentationtime was investigated. The results showed that the best outcomes were achieve with5%yeast inoculation and fermentation for48hours.3. The assessment of the essential nutritional ingredients of tea seed mealfermentation medium. The tea seed meal used in this study was dried, and the tea oiland saponin has been extracted. The main components of the tea seed meal were thesaponin5.15%, true protein2.3%, crude fiber30.0%, total soluble sugar8.9%. Thecontent of tea saponin is consistent with previous report, while true protein and totalsoluble sugar was low and crude fiber was in a high level. After anaerobicfermentation for3days, the true protein increased from2.3%to5.9%and crude fiberdecreased to27.8%; after further fermented by yeast under aerobic cond itions for48hours, the true protein was increased to7.4%, which was more than twice of theoriginal level and the crude fiber decreased to27.0%; the reducing sugar and totalsugar both dropped. The tea saponin level did not change significantly during thefermentation.4. The community structure of the ruminal bacteria and its succession during theprocess of anaerobic fermentation of tea meal was investigated using the method ofmetagenomic analysis with16S rDNA as molecular marker. The results showed that,the dominant bacteria changed from Bacteroidetes and Firmicutes to lactobacillusmucosae.Summary: After anaerobic fermentation using ruminal microbes for3daysfollowed by aerobic fermentation with yeast for2days under the conditions, trueprotein was increased to about twice of the original level and crude fiber decreased by3.0%, tea saponin level decrease slightly. However the fermented product doesn’tmeet the standard of protein feed. And the pH value was dropped, the communitystructure of ruminal bacteria was changed, the bacterial diversity was reducedsignificantly, during anaerobic fermentation. The reasons for these results remain tobe further investigated.