نشریه پژوهش های علوم دامی
سال بیست و دوم شماره 2 (تابستان 1391)

An experiment was conducted in order to evaluate the effect of different metabolizable energy and lysine levels on the growth performance and carcass quality of Arbor Acres(AA) broiler chickens. A total 180 of one day-old broiler chickens were randomly allocated to each of 6 treatments with 3 replicates in CRD design as factorial arrangement (2 metabolizable energy levels × 3 lysine levels) with 10 sex-mixed birds each. Three experimental bird groups received the experimental diets formulated to meet AA nutrient requirements for metabolizable energy with three levels of lysine (85, 100, and 115 percent of recommended level) and other three bird groups received the experimental diets with 200 Kcal/Kg deficient in metabolizable energy with same three levels of lysine. Except at 1- 14 days of age, feed intake, body weight gain and FCR of broilers were improved significantly (P<0.05) in standard energy level in other growth periods. With decreasing of lysine level in diets, feed intake and body weight gain was decreased at 1- 28 days but performance traits were not influenced by lysine levels in other growth periods. The results showed that may be used 85% of recommended level of lysine in diet at 28 - 49 days of age. Body weight gain and FCR was improved in standard level of energy at 1- 49 days of age. It was concluded that AMEn values were significantly (P<0.05) decreased with declining levels of metabolizable energy and lysine in broiler diets. Dressing percent and thigh weight percent was not affected by metabolizable energy and lysine levels. Breast weight percent and breast meat value decreased with lowering levels of metabolizable energy and lysine in diets.

In this study the yield, chemical composition, in vitro digestibility and gas production of forage from 18 different varieties of oat (Avena Sativa L.) was studied. All the oat varieties were grown under the similar agronomic condition in three replicates in a randomized complete block design at Research Farm of School of Agriculture, Razi University. Significant difference (P<0.01) was observed in the yield of forage (15.6 to 26.3 ton dry matter (DM)/ha) from different varieties. Crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) content varied from 52.2 to 122, 500 to 597, 306 to 400 and 33.1 to 58.0 g/kg DM in forages respectively. The in vitro dry matter and organic matter digestibility (IVDMD, IVOMD) and metabolizable energy (ME) were significant (P<0.01) differences between 18 varieties of oat forage. The variety 12 and V8 had the highest and lowest IVOMD, respectively (674 vs. 549 g/kg DM). The mean value of digestible OM yield (DOM) was 10.8 ton/ha. Variety 8 had the highest DOM (13.2 ton/ha). The potential of gas production (A), rate of gas production (c) and lag time (L) indicated significant difference among different varieties. The result of this study emphasized a great variation in chemical composition, digestibility and kinetics of fermentation in different varieties of oat. However the diversity in digestibility and total cumulative gas production was greater.