INFLUENCE OF LOW-PROTEIN LEVELS FORTIFIED WITH METHIONINE AND ENERGY ON PRODUCTIVE AND REPRODUCTIVE PERFORMANCE OF SILVER MONTAZAH LAYING HENS

The objective of the present experiment to determine the extent to which the crude protein (CP) content of laying hen diets can be reduced, based on fortified with methionine (Met.) to reach a level of sulfur amino acids equal with high-protein level and their effects on productive and reproductive performance of silver Montazah laying hens during 24-40 wks of age. One hundred and eighty hens 24-weeks old were housed in individually cages in factorial experimental design (2X3) involves 30 birds in each treatment. The experimental diets were formulated with two dietary metabolizable energy levels (low energy = 2700 and high energy = 2850 kcal ME / kg diet) and three dietary protein levels 14% low crude protein; 16% moderate crude protein and 18% high crude protein. The diets of 14 and 16% CP were fortified with methionine to reach the same level of SAA 18% CP-diet. Feeds and water were offered ad libitum. Fertility and hatchability percentage were determined at 37, 38 and 39 wk of age. All hens from each treatment group were artificially inseminated twice a week with a fixed volume of diluted semen (1:1) from cockerels fed diet containing 16% CP and 2750 kcal/kg diet. Results are summarized as follows: Significant increases were observed in final body weight (FBW), body weight change (BWC), metabolizable energy efficiency ratio (EER) feed conversion ratio (FCR), Egg production parameters; egg number (EN), egg weight (EW), daily egg mass (EM), hen-day egg production rate% (HDEP), cholesterol level in blood plasma and economic efficiency of feed parameters (EEF) due to feeding on high-energy diets, while birds fed on low-energy diets resulted in significantly (P≤0.01) increased in feed intake, daily protein intake, daily energy intake and daily methionine intake than that fed high-energy diet. The same manner was observed in respect of protein levels, where increasing protein content in the diet had a significant improvement (P≤0.01) in final body weight, change (BWC), daily protein intake, energy efficiency ratio, feed conversion ratio, egg number, egg weight, egg mass, hen day egg production rate, AST, and ALT in blood plasma. Interaction between energy and protein levels were significant effects on most studied traits, there were positive effects of different protein levels at high energy level on body weight, body weight change, energy efficiency ratio, feed conversion, egg number, daily egg mass, hen-day egg production rate%, egg fertility%, hatchability%, chick weight, most blood traits and economic efficiency of feed. However, neither energy nor protein levels significantly affected on egg quality, egg fertility percentage and chick weight. Based on performance outcomes hens fed high-energy diet with 14% or 16% protein level fortified with DL-methionine succeed in recording egg number and hen-day egg production rate like those fed on 18% protein. It could be concluded that reducing protein level fortified with DL-methionine in Montazah laying hens diets had beneficial effects on some traits but not all traits. From economic analysis of this study it can be used diets containing 2850 kcalME/kg diet with 14% or 16% CP fortified with methionine in feeding Silver Montazah laying hens during 24-40 weeks of age without negative effect on profitability.