| In recent years,probiotics as micro-ecological agents have been widely used in production.Lactobacillus plantarum(L.plantarum)is an important lactic acid bacteria which belongs to normal flora in animal gut.L.plantarum has good intestinal adhesion ability and can produce lactic acid and some antimicrobial substances,it also can regulate the balance of digestive tract microbial flora and inhibit the reproduction of Spoilage bacteria and pathogens in intestine,and promote digestion and absorption of nutrients and enhance immunity of body.However,the probiotic effect of probiotics is closely related to its quantity,the quantity plays a key role in maintaining healthy environment of intestine and improving immune function.At present,the oral route is the ideal means for feeding probiotics because of its high safety and low cost.However,the quantity of viable probiotics in this process will reduce due to the destruction of gastric acid,it is difficult to have sufficient numbers of viable bacteria to colonize in intestine.Microcapsule technology can significantly enhance the tolerance of bacteria to the outside environment and greatly improve the survival rate of bacterias in intestine.In recent years,studies have confirmed that there is a symbiotic relationship between probiotics and plant polysaccharides.Some plant polysaccharides not only can significantly promote the proliferation of Bifidobacterium,Lactobacillus acidophilus,but also inhibit the growth of Salmonella.The laboratory has confirmed that Taishan pine pollen polysaccharide(TPPPS)is an effective immune adjuvant.However,whether L.plantarum and TPPPS have synergistic probiotic effects remains unclear.TPPPS is a kind of water soluble plant polysaccharide which is easy to be damaged by acid and enzyme.In order to protect the biological activity of L.plantarum and TPPPS and explore whether they have synergistic effects,we prepared microcapsules with L.plantarum and TPPPS as core materials.The optimum conditions for the preparation of L.plantarum-TPPPS microcapsules were obtained by orthogonal design.The optimum conditions for the preparation of microcapsules as follows,the volume ratio of water phase to oil phase was 1?3,the mass ratio of CaCO3 to sodium alginate was 1?4,the molar mass ratio of CaCO3 to glacial acetic acid was 1?4,the concentration of chitosan was 4 g/L.The average particle size of microcapsules was 125.4 ?m,and the surface of microcapsules is smooth.The survival rate of L.plantarum was 62.36% in the environment of gastric acid,those results indicated that microcapsules can better resist the environment of gastric acid and reduce the destruction of acidic gastric juice to probiotics.Microencapsulation increased the number of viable probiotics in intestine.A total of 48 SPF rabbits were selected and randomly divided into 4 groups.I-IV groups were orally fed with 1.0 mL of L.plantarum,L.plantarum(0.5% TPPPS),microcapsule and PBS respectively.At 7,14,21,28,35 and 42 dpa,three rabbits were randomly selected to detect the level of antibody,lysozyme and IFN-? in serum.The colonization of lactic acid bacteria and Escherichia coli in small intestine were detected and the length of intestinal villi was measured at 0,14,28 and 42 dpa.The results showed that the effect of microcapsules was better than L.plantarum alone,microcapsules can increase the daily gain of rabbits,improve the microbial environment in intestine,promote the development of intestinal villi,increase the level of antibody,lysozyme and IFN-?.In addition,the effect of L.plantarum combined with TPPPS was also superior to that of L.plantarum.The results showed that L.plantarum and TPPPS had synergistic effects on the growth performance and immune function of rabbits,and their microencapsulation showed the most significant effects.Microcapsules provided important theoretical and practical basis for the development and utilization of L.plantarum and TPPPS in mammals. |
PDF Full Text Request