The effects of dietary vitamin A (Vit. A) supplementation before and during early egg production on productive performance, egg quality, and economical efficiency of Lohmann brown laying hens were studied. In this experiment, a total number of 375 hens 16 wks of age were fed a basal diet supplemented with 10,000 (control); 20,000, 30,000; 40,000 or 50,000 IU Vit. A/kg diet. Each dietary treatment was randomly divided to 5 replicates with 15 birds each. Water and feed in mash form were offered ad-libitum, under a total of 16 hrslight/day regimen during the experimental period. Birds were reared in clean batteries under similar conditions up to 30wks of age.
The results indicated that egg production, egg mass and feed conversion ratio (FCR) significantly improved (p<0.05) with vitamin A supplementation. Groups received 30,000; 40,000 or 50,000 IU Vit. A/kg diet showed improvement egg production% at peak production period compared with groups received which 10,000 or 20,000 IU Vit. A/kg. Neither external nor internal egg quality parameters were affected by Vit. A supplementation except yolk index that was significantly decreased with increasing Vit. A level in the diet. Hens received 20000 IU Vit. A/kg diet showed the better relative economical efficiency compared those received the other levels. It could be concluded that, although the supplementation of 50000 IU Vit. A/kg diets before and during the early egg production improved laying hen performance, the hens received 20000 IU Vit. A/kg diet showed the better relative economical efficiency.