Feed form and perch design do not interact to production performance, gastrointestinal tract traits, behaviour and welfare of laying hens reared in enriched cages.

1. It was hypothesised that perch material and design may affect utility and maintenance energy demand in laying hens, affecting their feed form preferences and daily feed consumption. Accordingly, perch design and feed form on hen performance, gastrointestinal tract functions and some behavioural and welfare-related traits were studied in laying hens (ATAK-S) reared in enriched colony cages from 24 to 40 weeks of age.2. The experiment was a 2 × 2 factorial investigating two perch materials and design (circular steel or mushroom-shaped plastic) and feed form (mash or crumble). A total of 396 hens were randomly assigned to one of the four treatment groups with nine replicates each (11 birds per replicate).3. Except for feeding behaviour and prevalence of foot pad dermatitis at 40 weeks of age, the modification of the perch design did not have a significant effect on the traits examined. Mushroom-shaped plastic perches reduced feeding behaviour (p < 0.01) and the incidence of foot pad dermatitis at 40 weeks of age (p < 0.001).4. Performance traits were not affected by feed form. Intake, final body weight and FCR for crumble-fed laying hens were greater than those fed mash (p < 0.01).5. Hens fed mash had higher (p < 0.01) relative gizzard weights along with lower (p < 0.05) pH values, pancreatic chymotrypsin, amylase and lipase activities (p < 0.05), and duodenal absorption surface areas (p < 0.01). Ultimately, this gave higher protein digestibility (p < 0.05) compared to those receiving crumble.6. In conclusion, in enriched cage rearing systems, mashed feed was preferred over crumble to efficiently maintain productive performance. Compared to circular steel, plastic mushroom-shaped perches were associated with better footpad health and welfare.

Comparison of different brown and white layer hybrid embryonic development and uptake of nutrients in the egg.

The objective of this study was to evaluate the comparison of different brown and white layers in embryonic development and uptake of nutrients in the egg. A total of 360 fertilized eggs obtained from two brown (Atak-S and Brown Nick) and two white (Atabey and Nick) layer breeders at 28 wk old. Hatching eggs from each genotype were examined on the day of setting for fresh egg analysis and then at the beginning of the embryonic day (E19) and embryonic day (E21) for egg, embryo and villus analysis. Differences in egg weight, shell percentages, relative weight of yolk and albumen, relative weight and length of embryo, villus height, some values of shell, yolk and albumen and relative chick weight in examined hybrids were significant. Yolk sac utilization of embryos during the incubation in the white layer hybrids was greater than that in the brown layer hybrids. Villus heights in the duodenum, jejenum and ileum of embryos in the brown layer hybrids was greater than that in the white layer hybrids. Genotype is important parameter to determine the egg composition at the same age and in animals being fed the same diet. It was observed that the consumption of yolk and shell nutrients from the embryos during the incubation was not related to whether embryos were from the brown or white layer hybrids. Only uptake of the yolk sac and villus height in the embryo among examined variables varied depending on whether the embryos were from the brown or white layer hybrids.

Differences in egg nutrient availability and embryo development in white layer breeder genotypes.

Because of consumers' preferences and also due to changes in production systems, the importance of pure breeds has increased again. There are a lot of differences among breeds which have been studied extensively, however, the differences during the incubation period are not yet fully known. Therefore, the present study was conducted to evaluate the composition of the egg parts, absorption of nutrients, and development of embryos from different genotypes. A total of 354 fresh hatching eggs were obtained from one hybrid (Lohman White, LW) and two pure breeds (Denizli and Gerze). Hatching eggs from each genotype were examined on the day of setting for egg analysis and then at the beginning of the embryonic d 19 (E19) and embryonic d 21 (E21) for egg, embryo, jejunum, and tibia analysis. On d 21 of incubation, the healthy chicks were removed and weighed. Egg weight, shell thickness, percentages of albumen, and some parameters of albumen composition (dry matter, water, ash, protein, energy, Na, Ca, K, and Mg) were higher in fresh eggs obtained from LW hens. Furthermore, the relative yolk sac and embryo weight, some yolk parameters (dry matter, water, protein, fat, and energy) and some shell parameters (dry matter, ash, Na, Ca, and K) were also higher in eggs obtained from LW hens during incubation. However, tibia deformation and villus width were lower in LW embryos than the other genotypes. Relative chick weights were 68.9, 72.0, and 68.0% in LW, Denizli, and Gerze genotypes, respectively. During incubation, differences in all examined parameters were significant except thickness and weight of shell, tibia deformation, and crypt depth. Yolk sac weight, some yolk composition parameters, K level in the shell, Cu level in the tibia, and villus height were also affected by genotype and period interaction. Based on these results, LW was found advantageous in terms of egg composition, however, regarding villus development and tibia deformation in embryos during incubation, pure breeds showed better results.