| The avian egg production has been the first in the world for 15 years. In recent years, the egg production has been more than egg consumption. There are abundant bioactive materials in egg, such as IgY, Iysozyme, and phospholipids etc. There are approximately 3 per cent of Egg Yolk Immunoglobulin (IgY) and more than 10 per cent phospholipids in the Egg Yolks of hens, IgY can be used as a food ingredient in infant formulae to treat dental caries.diarrhea~ dysentery etc. caused by pathogenic bacteria or virus; Phospholipids was intensively used as emulsifier, anti-oxidant in foods cosmetic and healthy food industry, and lysozyrne is a potential nature preservative.In these studies 3 Escherichia coli(E.coli.44555, 44336 & 4481 5),2 streptococcus mutan.s (S.mutcms 6715 & MT6R), I S.aureus and I human rotavirus (HRV) are used as antigens to immunize laying hens, the produced specific IgY. We find that the changing laws of antibodies in egg yolk and serum of laying hen are almost consistent, and the antibody Ievei in egg yok are always (more than 15 days after first immunization) high than that in serum. When several bacterins are used simultaneously, they can work in cooperation with each other.The quadratic rotary combination design is used to study the isolation of water-soluble proteins (Including IgY) from the Egg Yolk by simple dilution with water. The mathematic models of the study is established and the optimal conditions is obtained as followed An optimum Recovery of IgY (92.73%) and lipid (1.02%) were obtained by nine-fold water dilution at pH5.3 with incubation time of 2 hours at 15 ~C .Among the factors studied, pH was found to be the most important factor affecting IgY and lipid Recovery. Active IgY of high purity(95 %) with good recovery (63.4%) was o6tained by a combination of 4 procedures including ultraiiltration~ salt precipitation. ultrafiltration and chromatography with Sephadex 0200. Furthermore, the heating and storage stabilities of lyophilized IgY powder and lgY solutions are studied. We find the additions of protectors can improve the stabilities of IgY during high temperature (above 70t), and capsule fumigated with formaldehyde can prevent IgY from proteolysis.We also find IgY can restrain the growth of bacterium of its antigen, but can not kill them. Rat experiment indicate that anti-E.coli-IgY can prevent rats from diarrhea caused by E.coli. effectively, but its curative effect is not very good; Anti-S.mutans-IgY can control the occurs of caries of teeth caused by S.mutans effectively in virtoThe extraction of the egg yolk oil which was abundant in phospholipids from the precipitate of diluted Egg Yolk (DPEY, which were dried at55 ?X2, -O.OO8Mpa till less than 2 per cent water left)with solvent A is studied. About 49% egg yolk oil and more than 95% phospholipids(>60% in purity) is extracted by solvent A under following conditions: the purity of solvent A is 950/o(V/V), the ratio of solvent to EYDP is 9m1/g, incubating time is 3Omin,incubating temperature is under 35 C.Resin DC is found to have better adsorbing capacity to lysozyme by the comparison of 4 big-bore weak-acidic resins. Then an isolation method of lysozyme from egg white with resin D is established, and lysozyme recovery is 66.64%~?l.24%, the relative enzymatic activity of purified lysozyme is 20,946U1mg.Native Iysozyme is limitedly heated to make it partially unfolded. we found that heated lysozyme (HLz) can kill gram-negative bacteria such as Escherichia coli K12, but its antimicrobial activity is influenced by the concentrations of HLz or bacteria and solution environment etc. Rat feeding experiments shows native Iysozyme and HLz both can promote the proliferation of bifidobacterium in intestine.Wang jiaqi,Major:Animal food scienceTutor:Prof. Luo Chengxiang...
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