Physical quality parameters and activity of albumen lysozyme of eggs from traditional hens bred in Poland compared with commercial hybrids

The variation in eggs quality parameters of traditional/native hen breeds with good freshness and antibacterial properties of egg albumen may determine the attractiveness of these eggs for modern consumers looking for high quality products. The objective of this study was to evaluate external and internal physical quality parameters and enzymatic activity of lysozyme of eggs from three traditional hens bred in Poland and to compare this eggs quality parameters to those obtained from commercial hybrids kept under the same management conditions in extensive farming production system. The study was carried out on eggs collected from 4 genetic groups of hens, i.e. Polish Liliputy Bantams (PLB), native Polish Crested Chickens (PCr, CP–22 strain), Gold Laced Polish Chickens (GLP) and from Hy–Line Brown hybrids (HLB). In total 135 PLB, 75 PCr, 75 GLP and 75 HLB hens were kept on litter (3 pens) and fed commercial feed. The eggs (n = 33/genotype/age) were collected at the 33 and 55 weeks of age. The study concluded that with the age of the hens, there was an increase (P<0.05) in the weight of the egg and the proportion of its main fractions, as well as a decrease (P<0.05) in the quality parameters of the albumen and the eggshell. However the eggs from traditional breeds retain good parameters of albumen quality even at the end of production period. The eggs of traditional hens were characterized by higher (P<0.05) yolk proportion and its color and albumen lysozyme parameters, and a lower (P<0.05) eggshell and albumen height and Haugh unit score in relation to commercial hybrids. The highest (P<0.05) content of lysozyme and enzymatic activity of lysozyme were found in eggs from Gold Laced Polish Chickens. Thus, eggs obtained from traditional hens may meet requirements of modern consumers because of specific physical characteristics, good albumen lysozyme activity and freshness parameters. Particularly noteworthy are Polish Liliputy Bantams eggs, characterized by the low weight and a high proportion of more intensely colored yolk and good Haugh unit score at the end of production period.