Economic performance of diets formulated with different levels of energy and digestible amino acids in broiler chickens

Poultry industry is growing rapidly throughout the developing countries. There have been a considerable increase in growth rate and feed efficiency in commercial broiler chickens in recent years. The improvement of poultry production highly depends on the synergy between science and practice. By use of modern technology, genetics, microbiology, informatics and nutrition knowledge, production of fattening chicken highly increased in the whole world in last years. Also shorter production period and lower quantity of feed which is needed per kg of weight gain is the main goal of broiler production (Steiner et al. 2008). Poultry feeding is biologically and economically very important factor in broiler production. Feed cost is approximately 65-70% of the total production cost (Esonu et al. 2003). Energy and protein are very important nutrients for formulation of broiler diets. They are determinants in the evaluation of the performance and production coefficients of poultry. Protein and energy having major effect on growth performance of the broiler and they are the most expensive nutrient in broiler diets. Costs are rising along with the development of the poultry industry. Furthermore, there is a limitation on the feed sources which produced in Iran and to prevent loss of nutrients, evaluating the economy of poultry industry is important. Also there are several limiting factors such as environmental conditions which lead to lower weight gain and higher feed conversion ratio as compared to the standard performance in current broiler house in Iran. For these reasons, by feeding chickens with the diluted diets may achieve to the reasonable broiler performance while reducing the production costs. Therefore this experiment was conducted to evaluate the productive and economic performance of broiler chickens fed with different level of energy and digestible amino acids.
Material and This study was conducted at the veterinary organization of Khorasan Razavi. A total of 1440 day-old Ross 308 broiler chickens were reared with standard diet during the first ten days of age and then randomly divided into twelve treatment groups. The chickens were arranged as 3×4 factorial completely randomized experimental design according to 3 levels of energy (100, 95 and 90% of Ross 308 recommendation) and 4 levels of protein and essential digestible amino acids (100, 105, 95 and 90% of Ross 308 recommendations). Each treatment considered of 3 replicates of 40 chickens per experimental unit. The birds were reared on the litter pen for 42 days with ad libitum access to feed and water. Experimental diets were formulated to provide similar nutrients content (expect protein, amino acids and energy levels) according to the Ross 308 recommendations. The standard composition and analysis of the diets are given in Table 1. Diets were formulated base on linear programming by using of the UFFDA software. Feed intake (FI) and body weight gain (BWG) were recorded for each period on pen basis, and the data was used to calculate feed conversion ratio (FCR). Mortality was recorded on daily basis, and dead weight recorded to correct FCR. The economic evaluation was performed according to cost of feed intake per kg weight gain; that was calculated as multiplying FCR in cost of each kg diet (Obih and Ekenyem 2010). Data were analyzed using the General Linear Models (GLM) procedure of SAS (SAS, 2003). The differences between the means of groups were separated by Tukey Multiple Range test (P In case of energy levels, the main effects showed that, there was no significant difference between FI and BWG, whereas, feed cost per kg final BW was lower in the diet containing 90% energy. These results are in agreement with NRC (1994), which reported that it is not always true to conclude the poultry can adjust feed intake to achieve a minimum energy from diets containing different levels of energy. Similarly, Leeson et al (1996), Nguyen and Bunchasak (2005) and Jafarnejad and Sadegh (2011) found no significant effect on BWG of broiler chicks fed the diets containing different levels of energy. In the study using Hubbard × Hubbard broilers, Aftab (2009) reported that, the diets with the higher energy (2850 kcal) resulted to the lower feed intake and FCR in day 35.
Broilers fed with the diet containing 90% of amino acids had the lowest BWG and feed cost than those fed with other levels of amino acids. Aftab (2009) reported that with increasing balanced protein from 8.4 to 10.2 g per kg, the FI and BW linearly improved (p The present results demonstrated that balancing diets with 90% of amino acids and 95% of recommendation energy not only decreased feed cost but also partly improved performance of broiler chickens.