Hoda E. El-Gabry and Kh.M. Attia

 Anim. Prod. Res. Instit., Agric. Res. Center, Min. of Agric., Dokki, Giza, Egypt.

Abstract :

his experiment was conducted to determine the effect of vitamin D₃ and boric acid on eggT production, egg quality, hatchability of eggs, some blood constituents and mineral concentrations of egg shell and tibia. At 28 weeks old, a total of 360 Inshas laying hens and 36 cocks were randomly allocated to twelve diets in a 3 x 4 factorial arrangement of treatments. Three levels of vitamin D₃ (500, 1000 and 2000 IU/kg) and four levels of boric acid (0, 25, 50 and 100 mg/kg) were fed for 20 weeks. Birds were randomly divided into 12 groups. Each group consisted of 3 replications (10 hens+1 cock/replicate) and were housed in floor pens in an open-side housing system. Each diet was offered ad libitum. Results showed that egg production, egg weight, daily feed consumption and feed conversion ratio of the birds fed diet containing low level of vitamin D₃ was comparable to those fed diet containing adequate level of vitamin D₃. Similarly, the level of boric acid and /or vitamin D₃ in the diet did not have any effect on  the above parameters. However, the shell weight (%) of eggs laid by the birds fed the diet containing 1000 IU vitamin D₃ was comparable to 2000 IU supplemental groups but significantly higher when compared to those having 500 IU D₃. The Haugh unit, shell thickness, egg damaged, yolk index, yolk color, eggshell Ca, P, B and tibia B were not significantly influenced by vitamin D₃ concentration in the diet. Tibia ash, Ca, and P concentrations were significantly influenced by vitamin D₃ level in the diet. While, eggshell Ca, P, B and tibia ash, Ca and B were significantly influenced by boric acid levels. Total lipids, cholesterol, glucose, boron, iron, copper and zinc were affected by boric acid levels. Fertility, hatchability and chick weight at 1 day and 14^th day of age were not significantly influenced by dietary treatments. There were interaction between boric acid and vitamin D₃ levels on some blood parameters including total lipids, cholesterol, glucose, Ca, boron, iron, copper, zinc and eggshell Ca and boron as well as tibia ash, Ca, P and boron. It can be concluded that dietary treatments of boric acid and/or vitamin D₃ may not be essential for optimum production, shell quality, hatchability and some blood constituents of Inshas breeders during 28 to 48 weeks of age for birds housed in an open-side housing system.

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