Seasonal variations of yolk colour and IgY concentration in natural ...

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Kiss et al. Nitra 2010. 4„The yolk immunity evolves as IgY gets into the yolk through the endermic sporrancells of the ovary from the circulation of the mother. It’s amount can reach 8 mg/mldepending on the concentration of IgY in the laying serum. After the amphimixis, betweenday 1 and 14, it’s 25 μg/day, after this approximately 100 μg/day, and in the last days ofhatching the embryo absorbs 600 μg to it’s circulation. The hatching chicken has 1-2 mg/mlserum IgY concentration.” (Tuboly, 2002).Investigations in connection with the specific antibody produced in the egg took placein the end of the 19th century. In 1893 Klemperer wrote that after the vaccination of thelaying hens, specific antibodies appeared both in blood and in egg yolk. Long decades havepassed without confirmation.Interest in Klemperer’s researches rose when it came to the composition of ethicalguidelines for the animal league. In 1959, Russel and Burch completed the ethical studies onhuman researches and in the following 20 years Klemperer’s researches were quoted morefrequently.Since the 1980s, the specific antibody in egg yolk, IgY, became known as an availableand possible immunity method.For the first time since 1996, dr. Claus Staak put down the production method of IgYand the directions for its usage.In 1996, the European Centre for the Validation of Alternative Methods (ECVAM)was the first who recommended the usage of IgY, analog with the mammal IgG. Thissyndicate suggests the practical usage of IgY, that provides passive immunity with the eggyolk of laying hens.Since 1999, scientific articles mentions it as an alternative method in order to specificprotection of animals.Several scientific announcements has been published over the last decade about theextraction of IgY from the egg yolk, the measurement of concentration, the purification ofIgY, the specific healing and the prevention of diseases.Many researches supports the usage of antibodies in egg yolk, mainly because it canbe used for prevention and healing of bacterial infections of mammals. In 1994, Peralta andhis colleagues suggested IgY treatment for Salmonella infected mouses, and in 1998,Yokoyama and his colleagues achieved scpecific antibacterial effect on calves by feedingthem with IgY.In 1996, Schade wrote that IgY production is 18 times more efficient in laying hensthan in rabbits, immunized with it. Specific antibody concentration of an egg is 50-100
Kiss et al. Nitra 2010. 5mg/egg (Akita et al., 1992). During the laying of eggs, with 20 eggs / month productivity, 2 gantibody can be extracted from a laying hen per month.Physical and chemical characteristics of IgY:The isoelecronic point of IgY is lower than the IgG’s of mammals (Polson et al.1980), IgY spreads from 5,7-7,6, IgG spreads from 6,1-8,5.After the discovery of Fc-fragment, IgY is the least hydrofob antibody molecule(Davalos et al, 2000).IgY had been studied in acidic and alkalescent mediums. IgY activity decreased inmediums with 3,5 or lower pH. The molecule suffers irreversible changes at pH 3 (Shimizu etal., 1988, 1992, 1993). Lösch et al. (1986), Hatta et al. (1993), Lee et al. (2002) came to asimilar conclusion. The rapid drop in IgY’s activity is caused by the deterioration of its Fabregion. In alkalescent mediums, IgY molecule doesn’t show drop until pH 11. According tothe writers above, it is still active at pH 12.Proteolitic stability:IgY is partly resistant to tripsin and chymotripsin digesters, but especially sensitive tothe effects of pepsin digester. In 1993, Hatta and his colleagues revealed that after 8 hours,IgY loses its activity under the effect of pepsin, but in tripsin and chymotripsin, it still shows a39-41 % activity. IgY’s stablitiy against pepsin largely depends on pH and enzym / substratratio. In a medium with a 4,5 or lower pH, both of its activities stops (Shimizu, 1998).Temperature and pressure stability:IgY had been studied on different temperature for different durations. According to theexaminations of Shimizu (1992) and Hatta (1993), IgY molecule is stable between +20 °Cand +70 °C. A drop can be observed in stability below +15 °C and over +70 °C. IgYdenaturises if it’s kept over +75 °C (Chang et al., 1999).It’s natural that in case of biological samples, freezing, liofilization causesdeterioration in the quality and quantity of the matter. According to Shimizu (1988), freezingand liofilization has no effect on IgY.In 1998, Chansarkar revealed that IgY’s activity olny drops after freezing andliofilization if it was performed with high salt and protein concentration. In 2006, Fu came toa similar conclusion, when he studied temperature stability for 15 minutes between 25 and 90
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