Quality of Organic Eggs of Hybrid and Italian Breed Hens02 November 2012
The quality of organic eggs depends on genotype and environmental conditions, according to new research from Italy.
The quality of eggs laid by two hybrid and two Italian dual-purpose genotypes of hens reared under organic farming system was studied by C. Rizzi of the University of Padua in Italy and and A. Marangon of Veneto Agricoltura in Thiene.
In their paper in Poultry Science, they report that hens belonging to Hy-Line Brown (brown eggshell, HLB), Hy-Line White (white eggshell, HLW), Ermellinata di Rovigo (brown eggshell, E), and Robusta maculata (brown eggshell, R) genotypes were reared from 24 to 43 weeks of age. The trial was carried out from July to December, with environmental temperature ranging from 25°C (±5°C, summer) to 13°C (±7°C, autumn).
The HLB eggs were heavier (P<0.01) than HLW (62.9 versus 60.4g), and R eggs were heavier (P<0.01) than E (56.5 versus 54.4g).
The albumen weight differed (P<0.01) among HLB, HLW, R and E (40.7, 38.3, 32.7, 34.1g, respectively).
The E and R yolk weights were similar (16.2g) and higher (P<0.01) than hybrids; HLW yolk was higher (P<0.05) than HLB (15.8 versus 15.5g).
The HLB showed the highest (P<0.01, 6.74g) shell weight and E had the lowest (P<0.01; 5.43g).
The yolk cholesterol content was higher (P<0.01) in the Italian eggs than in the hybrids (258 versus 219mg per yolk). The HLB yolk had the lowest (P<0.01) saturated fatty acids (33.8 versus 34.9 per cent) and R yolks showed the lowest (P<0.01) monounsaturated fatty acids (36.3 versus 38.0 per cent) and the highest (P<0.01) polyunsaturated fatty acids (28.7 versus 27.4 per cent) than the other groups.
The HLW yolk showed the highest (P<0.01) n-6/n-3 ratio (13.7); 12.8 for the other three groups.
During a 21-day period of storage (21°C and 62 per cent relative humidity), the E eggs showed the lowest (P<0.01) quality (albumen height, 4.93 versus 5.56mm; Haugh units, 71 versus 74).
A sensory profile of boiled eggs showed differences (P<0.05) in odour and flavour sensations and in certain yolk and albumen texture properties according to genotype.
Rizzi and Marangon concluded that the quality of organic eggs from different genotypes differs in relation to the strain but also the interaction with the environmental conditions has to be considered.
Rizzi C. and A. Marangon. 2012. Quality of organic eggs of hybrid and Italian breed hens. Poult. Sci., 91(9):2330-2340. doi: 10.3382/ps.2011-01966
Further ReadingYou can view the full report (fee payable) by clicking here.