Egg quality traits, blood biochemical parameters and performance of laying hens fed diet included processed oak fruit

To investigate the effects of replacing maize with various levels of raw and processed oak fruit in diet on productive performance of laying hens and egg quality traits, the total number of 168 Bovans white laying hens (30‐week age) were randomly distributed between 28 replicate cages and assigned to 7 experimental diets. Based on a 2 × 3 factorial arrangement of treatments including two dietary levels (10% and 20%) of raw, soaked or boiled oak fruit as well as a corn–soybean meal‐based diet, 7 experimental diets with 4 replicates and 6 chickens per replicate cages were evaluated during an 8‐week period. The data were analysed using GLM procedure of SAS. Significantly higher feed consumption was observed in 10% boiled oak compared with soaked oak (p < .05). Significantly improved feed conversion ratio was observed in 10% boiled oak compared with soaked oak (p < .05). Diet inclusion of 10% oak fruit caused significant increased shell weight. Significant interaction between oak level and processing method on the egg‐specific gravity was observed (p < .05), and higher egg‐specific gravity was detected in hens fed the diets included 20% boiled or 20% raw oak compared to 20% soaked oak. Significantly increased blood LDL level was observed in hens fed the diets that included boiled and soaked oak (p < .05). In conclusion, based on the results of the present study, 10% boiled oak can be substituted corn in diet of laying hens with no unfavourable effect on performance.