فهرست مطالب آرش داوریان

Nutrition is the most important and cost effective factor in poultry production. By reducing the nutritional cost, the production efficiency increases and the use of feed additives as growth promoters in poultry feeding is a way to achieve this goal. Medicinal plants have beneficial properties due to the biological active compounds such as terpenes, phenols, ketones, esters, and alkaloids that improve the animal performance and health (Abaza et al. 2008). From the category of medicinal herbs, Nettle (Urtica dioica) and Elaeangus (Elaeagnus angustifolia) can be introduced which both are from Rosales order (Mohammadi et al., 2017). Nettles may be used in veterinary medicine because of its high levels of nutrients such as amino acids, minerals, vitamins, active compounds such as tannin, folic acid, salicylic acid, carvacrol, and thymol (Fu et al., 2007). Elaeangus is also a shrub or tree of the Elaeagnaceac family of the genus Elaeagnus, called Elaeagnus angustifolia (Khakrizi & Salehi, 2012). Phytochemical experiments showed that the Elaeangus contains high amounts of flavonoids, cytosterols, carbohydrates, folic acid, and ascorbic acid. It also contains potassium, magnesium, sodium, iron, calcium, zinc, malic acid and calcium malate. It is rich source of fatty acids including linoleic, palmitoleic, and palmitic acids (Ramezani et al., 2001). In general, natural-food products, especially medicinal plants containing active biological compounds, can create a favorable outlook to be used in poultry nutrition. The use of medicinal plant resources as feed additive is growing rapidly due to their active aromatic compounds, which benefits the host animal (Mohiti Asl et al., 2011). The experiment was designed and carried out using 128 commercial laying hens of W36 strain at 75 weeks of age with 4 experimental treatments, each group with 8 replicates and 4 birds per each replicate. A 14-day period was conducted to adapt the layers into the experimental diets. After this period, the main stage of the experiment consisted of 3 consecutive periods, each for 21 days, which totally with 11 weeks of the entire study period. During the experimental periods, the birds had free access to water and feed and the experimental diet was adjusted to maintain the requirements of the Hy-Line W36 (2014) breeding guidebook. The experimental groups consisted of: 1 (control): basal diet; 2: basal diet with 1% nettle powder; 3: basal diet and 1% Elaeangus fruit powder; 4: Basal diet plus 0.5% of nettle powder and 0.5% of Elaeangus fruit powder. The temperature and lighting program was also carried out according to the guide for breeding white Leghorn chicken (Hy-Line W36 strain). To evaluate the egg quality, three egg samples were taken and each egg sample was selected from each replicate. The sampling was done at the end of each periods. After sample collection, the weight of individual eggs were recorded using a digital top balance with 0.01 gram accuracy in the laboratory and later their individual specific gravity index were measured using a floating method in a salt water solution. The egg white quality was carried out by the Egg Multi Tester instrument (EMT-5200), (Leeson and Summers, 2005). To determine the thickness of the shell, Ultrasonic thickness Gauge (Echometer 1062 - Maks - USA) was used and to measure the shell resistance, the model-ll-MaksUSA device (Egg Shell Force Gauge) was used and the yolk color index was measured by the Rosche yolk color fan (Hosseini & Arshami, 2010). Shell weight were measured using a digital balance with an accuracy of 0.1 g (Leeson and Summers, 2005). The statistical analysis was done using SAS (2001) version 9.1. The highest amount of Haugh units belonged to the experimental group of Elaeangus fruit powder (1%) compared with control group and 0.5% nettle powder and 0.5% Elaeangus fruit powder group. The effect of experimental periods on the Haugh unit was significant and the highest number of Haugh units belonged to the second period, which had no significant difference with the first period, but showed a significant difference with the third period (P<0.05). The height of the egg white was statistically decreased in group 4 compared with control group (P<0.05). The effect of experimental periods on the height of egg white was significant and the highest amount was observed in the first and second periods compared with the third period (P<0.05). The experimental periods also had a significant (P<0.05) effect on the egg shell thickness, in which the highest amount was observed in the third period compared to the second period (P<0.05). Also, the interaction effect of the experimental periods and treatments on shell weight was also significant (P<0.05). Sayiedpiran et al. (2011) did not show any significant improvement using combination of extracts of thyme, mint, and Pennyroyal. Vakili (2011) indicated that, addition of essential oil of thyme and fennel into the diet of the laying hens, significantly improved the Haugh unit scores. Bird’s age and production stage are the effective factors on egg shell structure. The reason for improving the Haugh unit is attributed to the age of the bird, so the young birds have more Haugh unit scores. Also, Azghadi et al. (2010) reported no improvement in yolk color index using 0.1, 0.2, and 0.3% levels of thyme and cumin extracts. Vakili (2011) also stated in a study that adding 40 mg/kg of thyme extracts to the diet of laying hens showed no significant effects on egg shell quality parameters. Probably the reasons like the high age of chickens and the high temperature of the environment had a negative effect on the amount of calcium absorption to make the shell (Vakili, 2011). Considering the results obtained from current experiment, it can be concluded that the use of Elaeangus fruit powder at 1% can be recommended to be used in layers diet.