The Role of The Cuticle in Water Vapor Conductance by the Eggshell of Broiler Breeders ,

Abstract

Abstract The effects of cuticle removal on the water vapor conductance (G) by eggshells from broiler breeders were determined in five experiments. The efficacy of washing eggs in sodium hypochlorite (NaClO) as a means to remove cuticle was demonstrated in Experiment 1. Birds housed in slat litter pens were used in Experiment 2, 4, and 5, while individually caged birds were used in Experiment 3. Conductance measurements before and after cuticle removal were made in desiccators in Experiments 2, 3, and 4, and G measurements, with and without the cuticle, were made in incubators in Experiment 5. Conductance before and after cuticle removal was measured at various time periods between Weeks 33 and 66. Water vapor conductance was increased to a highly significant degree after cuticle removal at Weeks 54, 58, and 61 in Experiment 2. Conductance was significantly higher after cuticle removal at Weeks 42, 46, 50, and 54 and significantly lower after cuticle removal at Weeks 38 and 64 in Experiment 3. Conductance was significantly higher after cuticle removal at Weeks 33, 37, 45, 49, and 61 and significantly lower after cuticle removal at Week 65 in Experiment 4. The greatest changes in conductance with cuticle removal (AG) were + 1.80 at Week 33 and —2.40 at Week 65 in Experiment 4. In Experiment 5, G was significantly higher with the cuticle removed than it was with the cuticle intact at Weeks 48, 54, and 66. It was concluded that the cuticle may either impede or enhance water vapor diffusion as a function of a bird’s age. The influence of the cuticle is, in turn, affected by the humidity of the air surrounding the egg.