Abstract :

A

 total of 64 males and 192 females of Japanese quail breeders (Coturnix coturnix japonica) were divided into two groups of different ages (old birds; 52 weeks of age and young birds; 10 weeks of age). These subgroups were used in a series of four natural mating groups in a regular and reciprocal manner. In the 1^st and 2^nd mating groups; old males were paired with young and old females, respectively. While the 3^rd and the 4^th groups; young males were paired with young and old females, respectively. The first and the second subgroups of both ages (young and old) were subjected to a treatment of 20 ppm silver nanoparticles (AgNps) in drinking water. The third and fourth ones were used as a control treatment given fresh water with no supplement. Egg production parameters, feed consumption and feed conversion ratio were recorded biweekly. At the last week of the experimental period (8^th wk), birds were weighed and slaughtered, autopsied and some organs were weighed. Histological observation was done for liver, ileum, testis and sperm storage tubules of hens. The results showed that older age of quail had significantly higher egg weights compared to those produced from the younger ones. Also, administration of AgNps improved live body weight (LBW) and egg weight of female Japanese quail breeder hens. Insignificant interaction between both age at mating and silver nanoparticles was found on feed consumption (FC), feed conversion ratio (FCR) and body weight (BW). Histological examinations showed that AgNps may have minor negative impacts on the liver and ileum tissues of laying quails. It could be concluded from the present study that; it is possible to improve the productive performance and healthy status of aged Japanese quail breeder stocks if the old age female breeders are mated with younger male ones. The magnitude of this effect could be achieved through the administration of AgNps in their drinking water.   

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