Comparison of Egg Quality Characteristics, Blood Parameters and Liver Histology of Japanese Quails in Different Age Groups

Reproductive efficiency and egg production are decreased in aged birds, which are economically significant. The current study was aimed to compare the different ages of laying Japanese quails on egg quality characteristics, blood parameter and liver histology.

A total number of 180 laying Japanese quail were purchased from three commercial flocks with different ages studied for one week after four weeks of habituation. Birds were assigned into three age groups, young (11 weeks), adult (26 weeks) and old (45 weeks) with five replications (9 birds per replication). During of experiment, feedlot performance and egg quality parameters were evaluated. In the end of study, ten quail per treatment were randomly selected and dissected. Following this time, blood and liver samples were collected for evaluating blood biochemical parameters (triglyceride, cholesterol, low density lipoprotein (LDL), high density lipoprotein (HDL), very lowdensity lipoprotein (VLDL), aspartate transaminase (AST), alanine transaminase (ALT), total antioxidant capacity (TAC) and liver histology. The liver tissue was processed with hematoxylin-eosin after processing.

The findings showed that in old quails, a decreased the percentage of egg production and egg mass, and an increased the food conversion ratio and consumed feed per dozen eggs compared with other two groups (P<0.05). In adult and young quails had lower egg weigh, egg Length and width, yolk diameter, yolk weight, yolk percentage and albumen height than old group and Yolk index, albumen and shell percentage had higher (p<0.005). Old quails had higher Haugh unit and Shell weight than adult quails(p<0.005). In different age groups, Shape index, yolk height, egg white weight, and shell thickness were not significantly different. In adult quails Triglyceride and VLDL were higher than the other two groups (P<0.05). Total cholesterol, HDL and LDL were the highest in the adult group and the lowest in the old group (P<0.05). Old quails had more liver tissue damage than young quails.

In general, although the egg quality characteristics of Japanese quails increase with age, production performance decreased along with the decrease of blood lipid metabolites and the increase of liver damage.