Physicochemical characteristics of eggs deriving from laying hens reared in different housing systems

Abstract

The rearing and breeding of poultry both for meat and egg production has long been an important part of the Maltese agricultural activity. In fact, it can safely be said that historical evidence affirm the highly importance of poultry in the hands of Maltese farmers. This can nowadays be proofed by the presence of a local rustic dual purpose poultry breed known as the 'Black Maltese'. Nowadays local egg production has been entirely replaced by intensively reared hybrid strains of poultry, particularly those deriving from the White Leghorn and Rhode Island Red both of which are more productive. This research is based on the assessment and examination of the physical and chemical characteristics of eggs derived from two different housing systems for laying hens while taking also in consideration thermal conditions and flora availability for the free-range hens. Physical characteristics target weight and measurement of eggs, while more important chemical parameters are carotenoids in yolk and protein in albumen. The Carotenoid content in the eggs was evaluated by a new system that was recently developed by BioAnalyt GmbH, Teltow, Germany while the protein content was evaluated using a laboratory based method known as colorimetric analysis. The housing systems used for the research of the dissertation were the free-range and the enriched cage system. The specifications of both rearing systems are defined in COUNCIL DIRECTIVE 1999/74/EC of 19 July 1999 'Laying down minimum standards for the protection of laying hens'. The choice of the two rearing system was chosen taking into consideration the current global tendency in livestock production towards good welfare conditions. Although no free-range hens are reared on the Maltese islands mainly due to lack of land availability and allowed number of hens per hectare, free range eggs are gaining popularity by local consumers. For the free range hens, egg weight and size were higher during the first sixteen days, compared to the caged hens. It also resulted that the carotenoids content was higher in eggs obtained from free-range chicken when compared to those in enriched cages. The albumin content did not show any statistically significant difference. Changes in the thermal heat index did not influence albumin production. As part of the study a survey involving 96 consumers was also conducted. The aim was to sec if consumers are aware of different production systems of poultry and related animal welfare. The consumers were also asked to mark the preferred type and quantity of eggs consumed in their household. Results of this survey suggested that people are consuming less amounts of eggs, most probably due to healthy eating. Although consumers have become more aware of animal welfare and production systems, they are still considering the price, packaging convenience and locally produced eggs Animal welfare, sustainability and nutritious food are related terms in modem agricultural activities. Although free-range rearing systems contribute to animal welfare and to sustainability, there is a contradiction between what is environmental sustainable and economic viable especially on small scale production. The poultry industry in Malta is now stable with the implementation of EU Directive 74/1999. I am confident that through better promotion of healthy characteristics of free-range eggs such as Carotenoids, the demand for free-range eggs can increase. This would in tum encourage poultry producers to invest or start this potential niche market.