Effect of rearing techniques and feed composition on productive traits, bird welfare and quality of poultry products

The PhD project was focused on the study of the poultry welfare conditions and improvements. The project work was divided into 3 main research activities. A) Field evaluation of chicken meat rearing conditions kept in intensive farms. Considering the lack of published reports concerning the overall Italian rearing conditions of broiler chickens, a survey was carried out to assess the welfare conditions of broiler reared in the most important poultry companies in Italy to verify if they are in accordance with the advices given in the European proposal COM (2005) 221 final. Chicken farm conditions, carcass lesions and meat quality were investigated. 1. The densities currently used in Italy are in accordance with the European proposal COM 221 final (2005) which suggests to keep broilers at a density lower than 30-32 kg live weight/m2 and to not exceed 38-40 kg live weight/m2. 2. The mortality rates in summer and winter agree with the mortality score calculated following the formula reported in the EU Proposal COM 221 final (2005). 3. The incidence of damaged carcasses was very low and did not seem related to the stocking density. 4. The FPD scores were generally above the maximum limit advised by the EU proposal COM 221 final (2005), although the stocking densities were lower than 30-32 kg live weight per m2. 5. It can be stated that the control of the environmental conditions, particularly litter quality, appears a key issue to control the onset of foot dermatitis. B) Manipulation of several farm parameters, such litter material and depth, stocking density and light regimen to improve the chicken welfare conditions, in winter season. 1. Even though 2 different stocking densities were established in this study, the performances achieved from the chickens were almost identical among groups. 2. The FCR was significantly better in Standard conditions contrarily to birds reared in Welfare conditions with lower stocking density, more litter material and with a light program of 16 hours light and 8 hours dark. 3. In our trial, in Standard groups we observed a higher content of moisture, nitrogen and ammonia released from the litter. Therefore it can be assumed that the environmental characteristics have been positively changed by the improvements of the rearing conditions adopted for Welfare groups. 4. In Welfare groups the exhausted litters of the pens were dryer and broilers showed a lower occurrence of FPD. 5. The prevalence of hock burn lesions, like FPD, is high with poor litter quality conditions. 6. The combined effect of a lower stocking density, a greater amount of litter material and a photoperiod similar to the natural one, have positively influenced the chickens welfare status, as a matter of fact the occurrence of FPD in Welfare groups was the lowest keeping the score under the European threshold of the proposal COM 221 final(2005). C) The purpose of the third research was to study the effect of high or low stocking density of broiler chickens, different types of litter and the adoption of short or long lighting regimen on broiler welfare through the evaluation of their productivity and incidence of foot pad dermatitis during the hot season. 1. The feed efficiency was better for the Low Density than for High Density broilers. 2. The appearance of FPD was not influenced by stocking density. 3. The foot examination revealed that the lesions occurred more in birds maintained on chopped wheat straw than on wood shaving. 4. In conclusion, the adoptions of a short light regimen similar to that occurring in nature during summer reduces the feed intake without modify the growth rate thus improving the feed efficiency. Foot pad lesion were not affected neither by stocking densities nor by light regimens whereas wood shavings exerted a favourable effect in preserving foot pad in good condition. D) A study was carried out to investigate more widely the possible role of 25-hydroxycholecalciferol supplemented in the diet of a laying hen commercial strain (Lohmann brown) in comparison of diets supplemented with D3 or with D3 + 25- hydroxycholecalciferol. Egg traits during a productive cycle as well as the bone characteristics of the layers have been as well evaluated to determine if there the vitamin D3 may enhance the welfare status of the birds. 1. The weight of the egg and of its components is often greater in hens fed a diet enriched with 25-hydroxycholecalciferol. 2. Since eggs of treated groups are heavier and a larger amount of shell is needed, a direct effect on shell strength is observed. 3. At 30 and at 50 wk of age hens fed 25 hydroxycholecalciferol exhibited greater values of bone breaking force. 4. Radiographic density values obtained in the trial are always higher in hens fed with 25-hydroxycholecalciferol of both treatments: supplemented for the whole laying cycle (25D3) or from 40 weeks of age onward (D3+25D3)

Survey on chicken rearing conditions in Italy: effects of litter quality and stocking density on productivity, foot dermatitis and carcase injuries

1. A survey was carried out to assess some welfare indicators in broilers reared by the largest poultry companies in Italy, to determine whether they accord with European proposal COM (2005) 221 final. 2. Productive traits, carcase injuries and foot dermatitis were recorded from 279 640 broiler chickens reared in winter and in summer in 5 farms representative of the Italian production system. 3. The densities currently used in Italy are in accordance with the European proposal, which recommends that broilers are kept at a density lower than 30 to 32 kg live weight/m2 and not exceeding 38 to 40 kg live weight/m2. 4. Season markedly influenced broiler welfare status, with the worst score collected in winter cycles, when the recommended limit of 50 points for foot pad dermatitis was exceeded. 5. Stocking density is not a straightforward indicator for bird welfare; there was no relationship between stocking density and lesion incidence or mortality rate. 6. The control of environmental conditions, particularly litter quality, appears to be a key issue for broiler welfare

Contrôle de la calcification de la coquille selon différentes sources de vitamine D3 : régulation des transferts de calcium et des protéines de la matrice organique dans l'uterus

National audienceLa coquille d'oeuf de poule est un biominéral complexe composé de 95 % de carbonate de calcium et de 3,5 % de matrice organique qui influence sa structure et ses propriétés mécaniques. Le calcium nécessaire à sa formation est précisément régulé et stocké par différents organes pour permettre la biominéralisation de la coquille de l'oiseau. Le rôle de la vitamine D et de ses métabolites reste peu étudié au niveau de l'utérus où se produit la calcification de l'oeuf. Dans cette étude, nous avons étudié l'impact de la vitamine D3 (Cholécalciférol) et de sa forme intermédiaire hydroxylée (25-hydroxycholécalciférol) sur les mécanismes de formation de la coquille dans l'utérus de poule. Pour ce faire, nous avons nourri des poules de souche chair avec les 2 formes de vitamine D3 à des doses équivalentes, soit 3200 UI. L'analyse de l'expression des gènes dans l'utérus montrent que 34 gènes, codant pour les transporteurs d'ions qui permettent l'apport des minéraux nécessaires à la formation de la coquille, et 13 gènes codant les protéines de la matrice organique, sont significativement surexprimés, lorsque les oiseaux étaient nourris avec la 25-OH-D3. Les protéines de la matrice organique de la coquille ont été quantifiées par protéomique quantitative et l'utilisation de la forme hydroxylée a montré des différences significatives dans l'abondance de 55 protéines de la matrice organique associées à la biominéralisation. En conclusion, la vitamine D3 est un acteur important de la biominéralisation de la coquille d'oeuf aviaire et sa forme d'apport va influencer directement la structure et les propriétés mécanistiques de ce biomatériau

Existe -t-il des marqueurs métaboliques de la qualité de la coquille chez la poule pondeuse ?

International audienceChez la poule pondeuse, la formation journalière de la coquille nécessite une exportation massive de calcium(Ca) vers l’utérus en provenance de l’alimentation et du squelette. Avec l’âge, les os ont tendance à se fragiliser,la qualité de la coquille se détériore et le bilan phosphocalcique est souvent perturbé. La recherche de marqueursprécoces, prédicteurs d’une dégradation du squelette et/ou de la qualité de la coquille, permettrait d’anticiper lescarences et adapter suffisamment tôt l’alimentation. Pour ce faire, deux lots de poules sélectionnées sur unebonne ou une mauvaise qualité de coquille ont été suivis longitudinalement entre 26 et 96 semaines (S) d’âge.Des prélèvements sanguins ont été réalisés à l’âge de 26, 46, 84 et 96S afin d’étudier les activités d’accrétion(Ostéocalcine) et de résorption (CTX) osseuses, le statut circulant en 25-OH-vitamine D3 ainsi que lemétabolome sanguin. La teneur plasmatique en 1,25-OH2-D3 a été déterminée à 96S. A 96S, les analyses dumétabolome ne présentaient aucune différence significative entre les deux groupes. Cependant, chez les poulessélectionnées sur une bonne qualité de coquille, les niveaux plasmatiques de 1,25-OH2-D3 et CTX étaient plusélevés par rapport aux poules présentant une qualité de coquille plus faible. Le suivi longitudinal a mis enévidence une hausse précoce (dès 26S d’âge) de la 25-OH-D3 et du CTX chez les poules présentant la meilleurequalité de coquille. Le statut en 25-OH-D3 ainsi que le CTX pourraient être des marqueurs précoces de la qualitéde coquille