Within of the project “Sicurezza ed aspetti tecnico-economici e giuridici delle produzioni biologiche”, the work of the research group of DIMORFIPA dealt with the study of organic egg production. In the present paper are shown the results of a trial carried out during the first year of the project concerning the influence of housing system (outdoor vs battery cages) and feeding (conventional vs. organic diets) on some egg qualitative characteristics. During a four month-period, four groups of 27 Warren Isa Brown (8.5-9-month-old) laying hens were studied: AT (in which hens were kept outdoor and fed a conventional diet); AB (in which hens were kept outdoor and fed an organic diet); GT (in which hens were kept into battery-cages and fed a conventional diet) and GB (in which hens were kept into battery-cages and fed an organic diet). The diets were formulated so as to supply the same amount of protein and energy. Freshly laid eggs were collected at the beginning of the trial and every three weeks up to the end of the trial to determine some physical and qualitative parameters. Feed intake and egg production of groups AT and GT were, on the whole, higher than those of group AB+GB. All the eggs were classified into the category L, with a weight comprised between 63.00 and 72.99 g (Regulation EC No. 2295/2003, modified by Regulation EC No. 1515/2004). At the end of the trial, the heavier eggs were observed in groups fed the conventional diet, while the higher percentage of eggshell was detected in eggs of group AT+AB. The natural daylight and motor activity of outdoor animals were supposed to increase mineral metabolism leading to a better mineral deposition into eggshell. Haugh index and pH values were improved in eggs deriving from hens allocated in cages. Yolk from groups AT and AB was heavier and more intensively coloured, owing to the possibility to eat feeds containing xanthophylls, such as grass, herbs and insects. The comparison between the type of diets (conventional vs organic ) did not pointed out any significant difference. Based on these results, we can conclude that some egg quality characteristics can be significantly influenced by the housing system and only at a slightly extent by the diet. During the following year 2004 and according to the above described experimental design, a second trial has been carried out. Besides the productive and qualitative analyses of eggs, some behavioural parameters of hens were collected. The housing system was confirmed as the main factor affecting birds’ behaviour: regardless of feeding type, free-range farming reduced some abnormal behaviour of hens such as the over-explorative behaviour at feeder and improved the quality of the plumage. These results might account for the attainment of a higher degree of welfare for free-ranged layers, which is worthy of note considering that organic hens must have access to outdoor areas.

Effetti del metodo biologico sulla produzione quanti-qualitativa delle uova e sul benessere delle galline ovaiole

RIZZI, LAURA;MARTELLI, GIOVANNA;SARDI, LUCA
2007

Abstract

Within of the project “Sicurezza ed aspetti tecnico-economici e giuridici delle produzioni biologiche”, the work of the research group of DIMORFIPA dealt with the study of organic egg production. In the present paper are shown the results of a trial carried out during the first year of the project concerning the influence of housing system (outdoor vs battery cages) and feeding (conventional vs. organic diets) on some egg qualitative characteristics. During a four month-period, four groups of 27 Warren Isa Brown (8.5-9-month-old) laying hens were studied: AT (in which hens were kept outdoor and fed a conventional diet); AB (in which hens were kept outdoor and fed an organic diet); GT (in which hens were kept into battery-cages and fed a conventional diet) and GB (in which hens were kept into battery-cages and fed an organic diet). The diets were formulated so as to supply the same amount of protein and energy. Freshly laid eggs were collected at the beginning of the trial and every three weeks up to the end of the trial to determine some physical and qualitative parameters. Feed intake and egg production of groups AT and GT were, on the whole, higher than those of group AB+GB. All the eggs were classified into the category L, with a weight comprised between 63.00 and 72.99 g (Regulation EC No. 2295/2003, modified by Regulation EC No. 1515/2004). At the end of the trial, the heavier eggs were observed in groups fed the conventional diet, while the higher percentage of eggshell was detected in eggs of group AT+AB. The natural daylight and motor activity of outdoor animals were supposed to increase mineral metabolism leading to a better mineral deposition into eggshell. Haugh index and pH values were improved in eggs deriving from hens allocated in cages. Yolk from groups AT and AB was heavier and more intensively coloured, owing to the possibility to eat feeds containing xanthophylls, such as grass, herbs and insects. The comparison between the type of diets (conventional vs organic ) did not pointed out any significant difference. Based on these results, we can conclude that some egg quality characteristics can be significantly influenced by the housing system and only at a slightly extent by the diet. During the following year 2004 and according to the above described experimental design, a second trial has been carried out. Besides the productive and qualitative analyses of eggs, some behavioural parameters of hens were collected. The housing system was confirmed as the main factor affecting birds’ behaviour: regardless of feeding type, free-range farming reduced some abnormal behaviour of hens such as the over-explorative behaviour at feeder and improved the quality of the plumage. These results might account for the attainment of a higher degree of welfare for free-ranged layers, which is worthy of note considering that organic hens must have access to outdoor areas.
Gli alimenti biologici: dal produttore al consumatore
123
143
Rizzi L.; Simioli M.; Martelli G.; Paganelli R.; Scalabrin M.; Sardi L.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/39462
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