Screening Of Oil-tea-cake Probiotic And Optimization Of Fermentation Conditions

With the improper use and even abuse of antibiotics in animal husbandry and feed industry,some disadvantages have emerged and become increasingly prominent.Therefore,it has become a research focus in animal husbandry to find a green feed additive product which can replace antibiotics without pollution and side effects.Probiotics has become one of the hot topics in the research of antibiotic substitutes,which can regulate the microecological environment of digestive tract,maintain the balance of intestinal flora,assist digestion and absorption,improve feed utilization,enhance the function of animal immune system,and improve the ability of production and reproduction and disease resistance.Oil-tea-cake is the main by-product of oil-tea camellia after processing and refining.Because it contains many biological activity substances,it can be processed into a variety of high value-added products.It has a wide range of uses and can bring huge economic benefits.However,in the process of practical application,the resource of oil-tea-cake is wasted because of the development extent is far from insufficient.Therefore,it is urgent to study the comprehensive development and utilization of oil-tea-cake.This study through the fermentation of oil-tea-cake and use natural fermented oil-tea-cake isolate Lactobacillus and Bacillus in chicken intestines,based on morphological,physiological and biochemical test and molecular biology methods for species identification of strains,isolated from the acid test,the bacteriostatic experiment,temperature tolerance,growth characteristics,can produce acid such as biological characteristics and drug sensitivity in screening for poultry probiotics of Lactobacillus and Bacillus strains.Culture of Lactobacillus and Bacillus with oil-tea-cake,soybean meal and corn meal to optimize fermentation medium formula and fermentation conditions.The main findings are as follows:1)Three strains of Lactobacillus gigeriorum(L03),Pediococcus acidilactici(L04)and Lactobacillus crispatus(L09)were screened through acid tolerance and antibacterial tests.After 24 hours of anaerobic culture at p H 2.5 under acidic conditions,the count of viable bacteria could still reach10~4 cfu/m L.After 24 hours of anaerobic fermentation,the p H of the supernatant decreased from 5.8 to 3.8,which proved that it had good acid producing energy.2)One strain of Bacillus velezensis(Bv1)was selected for tea seed meal fermentation.The screening results showed that strain Bv1 had good tolerance to high temperature conditions and strong tolerance range to acid and base.The results of the growth curve showed that the content of live bacteria in Bv1 was higher in the stable growth period and the growth rate was faster in the logarithmic growth period.Drug susceptibility tests showed that strain Bv1 had strong resistance to 9 common antibiotic drugs.3)With the selected excellent strains of Lactobacillus and Bacillus as test strains,the optimal medium formula for tea seed meal fermentation was obtained by response surface test:63%oil-tea-cake,21%soybean meal,6%corn meal,6%bran and 4%zeolite.The optimal fermentation conditions were:temperature 37°C,fermentation time 74 hours,material-water ratio0.7:1.Under this optimization scheme,the number of viable bacteria measured reached 7.89×10~9 cfu/g,which was very close to the predicted value.