EFFECT OF DIET DILUTION IN THE STARTER PERIOD ON PERFORMANCE AND CARCASS CHARACTERISTICS OF BROILER CHICKS

The effect of energy and protein dilution in the starter period (8 to 14 days) of age, on performance and carcass characteristics of 360 Arian male chicks was studied in a completely randomised design. This experiment consisted of 6 treatments, 4 replicates, with 15 chicks per replicate. In order to dilute the diets six levels (0, 4, 8, 12, 16, and 20) percent of ground wood charcoal was used. Chicks were fed with starter and grower diet from 15 to 21 and 22 to 42 days of age respectively. During the experiment feed intake, body weight gain, feed conversion ratio were measured weekly. Mortality was measured throughout the experiment. At 43 day of age 4 chicks each treatment was selected and carcass characteristics were measured. The results indicated that dilution of diet from 8 to 14 days of age increased feed intake in this period but the differences were not signifi cant. With increasing dilution rate body weight gain of chicks signifi cantly decreased in comparison to control group (P< 0.05). Due to compensatory growth after restricted period, there was not signifi cant difference in body weight among restricted and control groups at 42 days of age. There was not signifi cant difference among the treatments for feed conversion ratio in whole period of the experiment (8 to 42 day). Similarly, there was not signifi cant difference among the treatments for caloric conversion ratio in whole period of the experiment (8 to 42 day). Mortality rate in restricted groups was signifi cantly lower than control group (P<0.05). Diet dilution hadn’t signifi cant effect on carcass, breast meat, drumsticks, thighs, liver, intestine, abdominal fat percentages. The results of the present study indicated that broiler chicks could withstand a 7-day period (from 8 to 14 days) feed restriction with ground wood charcoal in early age without loss in performance

Measurement of genetic parameters within and between breeder flocks of Arian broiler lines using randomly amplified polymorphic DNA (RAPD) markers

The present study was carried out in an attempt to detect the genetic variation within and between four populations of commercial broiler lines using RAPD markers. Thirteen out of twenty random markers which were amplified and generating stable and reproducible bands were selected for genotyping of birds in each broiler lines. The average number of diagnostic bands per primer was 8.08 with an average number of 6.96 polymorphic bands across all breed groups. The highest (94%) and the lowest (73.5%) percentage of polymorphic bands were found within sampled birds of Arian C and D lines, respectively. Among the studied broiler lines, the highest genetic uniformity was found in line A, while the greatest within population genetic diversity was found in line C. Estimation of polymorphic loci, Nei’s gene diversity and intra-population uniformity indices suggested that genetic diversities within Arian commercial lines is high. The four strains of broiler lines clustered into two main groups using UPGMA procedure. In the first main group, the closest genetic distance was found between A and B strains, which were first clustered together and then with birds of C strain. The second main group includes birds from D strain. The mean coefficient of gene differentiation (Gst = 0.368) value reflected a high level of population differences. In total, sixty three RAPD bands were found to be strain dependent specific. Therefore, in order to design new diagnostic primers more effective in genetic discrimination among studied lines, unique bands should be cloned and sequenced.Key words: Genetic variation, broiler lines, polymorphism, random amplified polymorphic DNA markers

Effect of supplemental fat in low energy diets on some blood parameters and carcass characteristics of broiler chicks

This experiment evaluated the effects of two fat sources on performance, some blood parameters and carcass characteristics of broiler chicks. One hundred and eighty day-old broiler chicks were randomly assigned to five dietary treatments (three replicates of 12 birds per treatment). The experiment was performed as a completely random design (CRD) and birds were fed isoenergetic and isonitrogenous diets containing no fat (control), 20 and 40 g soyabean oil, 20 and 40 g beef tallow/kg feed from 11 - 42 d of age. Food intake and body weight gain both increased significantly with supplemental level of both fat sources, the rate in food intake being higher with soyabean oil than with beef tallow. Feed conversion ratio decreased significantly with both sources in the period 29 – 42 d. Serum triglyceride and very low density lipoprotein (VLDL) contents were unaffected by dietary oil inclusion but cholesterol, high- (HDL) and low (LDL) density lipoprotein contents increased significantly with oil level. Serum glucose (GLU) content decreased significantly with increasing oil inclusion. In all cases the blood parameters responded significantly differently to the two supplemental fat sources with the rate of reduction in GLU, cholesterol and LDL, and the rate of increase in TG, HDL and VLDL being greater with soyabean oil than with beef tallow. Liver and abdominal fat percentages increased significantly with supplemental fat inclusion. The results indicate that supplementation of broiler diets with up to 40 g soyabean oil/kg feed significantly improved the performance and reduced serum cholesterol, LDL and abdominal fat in comparison with chicks receiving diets containing beef tallow.Keywords: Supplemental fat, low energy diet, blood parameters, broiler chick