عنوان مقاله [English]
Introduction It has been estimated that feed is the major cost associated with commercial poultry production. Hence, inclusion of non-conventional feed resource becomes of primary importance in livestock production to maintain the productivity at a lower cost. Date palm fruit is one of the most important products of Middle East countries and its byproduct can help to lowering the feed cost in livestock nutrition.
There are a few studies about use of date palm byproduct in poultry nutrition and especially in laying hens diets, therefore, in this study, we considered the effect of different levels of date waste powder on laying hens performance.
Materials and Methods Two independent experiments were conducted to determine the nutritional value of date waste powder (DWP) and its effects on performance and egg qualitative traits of laying hens. In the first experiment, AOAC method was used for determination of proximate analysis of DWP. In the second experiment, a total of 144 Hy-Line W-36 leghorn hens (at 46 wk old) were housed in cages and randomly allocated to 6 treatment groups for 6 weeks. Each group was divided in to 4 replicates. Feed and water were provided ad libitum. The hens received basal diet (corn and soy based diet with 15.00 % crude protein and 2820 kcal/ kg ME) that was formulated to meet the Hy-line W36 requirements recommended for nutrients. The diet did not have any antibiotics and coccidiostats. Treatments were included 0, 5, 10, 15, 20 and 25 percentage of date waste powder by expense of corn in basal diet. Experiment was designed in a completely randomized design. Egg weight (gr), egg production (%) and egg mass (gr/hen/day) were recorded daily. Feed consumption was measured weekly and feed conversion ratio (FCR) (grams of feed: grams of egg mass) was calculated weekly too. At the end of weeks 2, 4 and 6 of the experiment, two eggs from each replicate were randomly selected for measurement the egg qualitative traits.
Results and Discussion The results of these experiments showed that gross energy (GE), crude protein (CP), ether extract (EE), crude fiber (CF), calcium and ash of DWP were 4663 (Kcal/Kg), 7.17 (%) 11.45 (%), 30.64 (%), 0.63 (%) and 2.06 (%) of dry matter, respectively. Feed intake, egg weight and feed conversion ratio of the laying hens were not affected by inclusion different levels of dietary DWP. Egg production and egg mass were highest in 25% of DWP inclusion. This result may be related to the high levels of vegetable oil in this diet to maintenance the energy level. Adding vegetable oil to the diet increase the palatability of the diet, reduce dust and improve food texture and consequently increased nutrient utilization. Dietary inclusion of 25% DWP significantly decreased haugh unit of eggs compared to the 5, 10 and 15% inclusion level. Low availability of amino acids in this level may reduce albumen height. Egg yolk color decreased significantly at 10 and 15 % DWP rather than control group and increased in higher levels of DWP. Plant oils contain carotenoids, which can increase yolk color. Therefore, based on the results of this experiment, it could be concluded that inclusion of DWP in 20 and 25% can improve egg production of laying hens, and economically, the cost spent for producing one Kg egg, when using high levels of DWP was comparable with conventional commercial diets.