Two hundreds and twenty-five male Hubbard broiler chicks at one day old were divided into five groups (45 chicks each.). Each group was assigned for one of five experimental diets. The first group was fed starter diets (0-2 week), grower diets (2-4 week) and finisher diets (4-7 week) as a control diets. However, the groups 1,2,3 and 4 were fed on the control diet with the addition of Micro-Bac (LA), Avi-Bac (LAE), LA + LAE and LAE + LA respectively. At the 7th week of age, nine birds of each group (Three per each replicate) were slaughtered and blood samples were taken at slaughtering to determine serum cholesterol. Representative samples of fresh white breast meat were analyzed for chemical composition. The pH and plasticity of meat (breast and thigh) were determined after slaughtering at 0.5, 2, 4, 6, 24, and 48 h during storage at 4°C and cooking loss of meat was determined after 24 h. Contents of digestive tract were collected to determine the total bacterial count, total lactic acid bacterial count, L.acidophilus count, Coli form bacteria, Salmonella viable count and Staphilococcal viable count. Supplementing the basal diet with either LA or LAE gave no significant differences in body weight gain, feed intake and feed conversion at 2, 4 and 7 weeks of age. However, there were improvement in body weight gain and feed conversion in chicks fed LA+LAE at 2, 4 and 7 weeks of age by 9.0, 4.7, 2.8% and 1.5, 8.2 and 10.6, respectively.
On the other hand, LA supplementation and/or LAE to broiler has been shown to decrease the mortality rate compared to the control group. No significant differences were observed in the percentage of dressing, and abdominal fat between chicks fed basal diet (control group) and these of other treatments.
The meat of supplemented treatments were lower tender as indicated by lower plasticity values when compared with control diet. The lowest value of cooking loss was that of the control supplemented treatments tended to decrease the total cholesterol, triglycerides, HDL, and LDL in meat and serum cholesterol. All supplemented treatments inhibited bacterial growth of pathogenic bacteria.