Comparative Studies of Yolkin Preparations Isolated from Egg Yolks of Selected Bird Species

Abstract

The results of our research have proven that yolkin preparations isolated from eggs of different bird species show a high similarity in polypeptide composition. Despite the small differences in protein patterns, all of yolkin preparations showed also strong immunomodulatory activity, comparable with yolkin obtained previously from hen egg yolk. It can therefore be deducted that the presence of this polypeptide complex in the egg is not accidental and performs an important biological function for developing embryo.

Importance for humans of recently discovered protein compounds – yolkin and yolk glycopeptide 40, present in the plasma of hen egg yolk

“…It is well worth noting that the peptide composition of Y from eggs laid by wild species is very similar to those from burrowing birds. Also, almost the same Y compositions were observed for eggs from domestic and water birds ( Zabłocka et al, 2021a ).…”

“…The precursor of the main proteins of the granular fraction, such as α- lipovitellins and β-lipovitellins, phosvitin, and HDL lipoproteins, is Vt ( Yamamura et al, 1995 ; Finn, 2007 ; Réhault-Godbert and Guyot, 2018 ; Kazana et al, 2020 ; Zabłocka et al, 2021a ). Chicken Vt is synthesized in the hen's liver.…”

“…It is a heterogeneous mixture, usually consisting of several polypeptides of molecular weights ranging from 1 to 35 kDa, with fractions from 16 to 23 kDa being the most abundant ( Polanowski et al, 2013 ). Y complex is present in egg yolk from different bird species; however, an electrophoretic analysis revealed significant differences in Y peptide composition ( Zabłocka et al, 2021a ). For example, proteins of about 30 to 35 kDa had a small share in the composition of Y obtained from goose and quail egg yolks.…”

“…The protein profile of Y does not depend just on the bird species. The proportion of polypeptides can vary greatly depending on the time when the eggs were collected or even on the pen, and other factors ( Polanowski et al, 2013 ; Zambrowicz et al, 2017 ; Zabłocka et al, 2021a ). Y obtained by Zabłocka et al (2021a) was composed mainly of proteins of about 30 to 35 kDa and minor proteins of about 20 to 25 kDa, while fractions from 16 to 23 kDa were most abundant in Y obtained by Polanowski et al (2013) .…”

“…The proportion of polypeptides can vary greatly depending on the time when the eggs were collected or even on the pen, and other factors ( Polanowski et al, 2013 ; Zambrowicz et al, 2017 ; Zabłocka et al, 2021a ). Y obtained by Zabłocka et al (2021a) was composed mainly of proteins of about 30 to 35 kDa and minor proteins of about 20 to 25 kDa, while fractions from 16 to 23 kDa were most abundant in Y obtained by Polanowski et al (2013) . Y preparation obtained by Zabłocka et al (2014) using gel permeation chromatography was composed of peptides from 20 to 37 kDa, and predominant peptide fractions of about 23 kDa.…”