An experiment was conducted to investigate the effect of different dietary
energy and protein levels with small or large body weight on performance of
Gimmizah layers. Two hundred and eighty eight laying hens at 24 weeks of age
laying hens were randomly distributed into twelve equal groups, each one composed
of 24 females. Birds were housed in individual cages, fed on twelve experimental diets
containing 2 levels of metabolizable energy (2600 and 2800 kcallkg feed) and 3
levels of crude protein (12, 14 and 16%) with small or large body weight in a factorial
arrangement design (2 body weight x 2 energy level x 3 protein levels). The obtained results can be summarized as follows: 1- Regardless of dietary protein levels and dietary energy levels body weight class
did not significantly affected in feed intake (FI), average egg weight (EW), egg
mass (EM), feed conversion (FC), feed conversion (FC), egg quality traits and
hatchability and fertility percentages. 2- Independently of the effect of body weight class and dietary energy levels,
Significant improvement was recorded in egg production (EP), egg number (EN),
egg weight (EW), and egg mass (EM) with the increase in dietary protein level.
Feed conversion (FC) was improved as dietary protein levels increased. Egg
quality traits were not significantly affected by feeding different levels of crude
protein (CP), except egg shell weight % and Haugh Units score. Fertility and
hatchability of total eggs of low CP level were significantly lower than those of the
other levels. 3- Regardless of body weight class and dietary protein levels, dietary energy levels
had no effect on change in body weight. Feed intake significantly decreased due
to increasing dietary energy levels. The increase in dietary energy level
significantly improved EW, and EM. FC was improved as dietary energy
increased. Egg quality traits were not affected significantly by feeding different
levels of CP except egg shell weight % and Haugh Units score. Hatchability and
fertility percentages did not significantly differ in body weight categories and
dietary energy levels In conclusion. the diet containing 2800 kcal/kg diets and 16 or 14% CP levels
were suggested to be suitable requirement and satisfactory for egg production of
Gimmizah hens at the laying period (during the 90 days in production after 24 weeks
of age). Such results will help to reduce the cost of the diets for Gimmizah strain.
Dietary energy level is the main factor determining the efficiency of feed utilization.