SummaryShaddel-Tili, A., B. Eshratkhan, H. Kouzehgari & M. Ghasemi-Sadabadi, 2017. The effect of different levels of propolis in diets on performance, gastrointestinal morphology and some blood parameters in broiler chickens. Bulg. J. Vet. Med., 20, No 3,[215][216][217][218][219][220][221][222][223][224] A study was conducted to determine the effect of different levels of propolis in diets on performance, carcass characteristics, gastrointestinal morphology and some blood parameters in broiler chickens. A total of 224 one day-old Ross 308 chicks were randomly allocated to one of the 16 floor pens in a completely randomised design (four treatments, four replicate groups, 14 chicks in each group). Dietary treatments consisted of 4 different levels of propolis powder including zero (control), 500, 1500, 2000 ppm in the diet throughout the entire experimental period (42 days). The feed was offered ad libitum. All the chickens were grown up in the same environmental and management conditions. Body weight gain, food intake and feed conversion ratio were measured at the end of each period, also, the production index was calculated at 42 days of age. At the end of experimental period, two chicks from each pen were selected and after blood sample collection were slaughtered and dissected manually. Haematological and biochemical parameters as well as carcass characteristics, gastrointestinal morphology were determined. The use of 2000 parts per million propolis powder in diet improved body weight gain, feed intake, feed conversion ratio and production index at all experimental periods (P<0.05). High dietary levels of propolis powder in diets increased the relative weight of crop, thighs and length of gizzard compared to other treatments, and decreased the relative weight of livers of broiler chickens (P<0.05). PCV and heterophil counts were significantly increased (P<0.05). It is suggested that the supplementation of propolis powder to poultry diets had a positive effect on growth performance, carcass characteristics and blood parameters.

This study was conducted to determine the effects of fermented milk products and probiotic on performance, carcass characteristics, blood parameters, and gut microbial population in broiler chickens. A total of 480 one-day-old Ross 308 broilers were allocated to 30 floor pens in a completely randomized design with six treatments, five replicates, and 16 chicks (eight males and eight females) in each replicate. On the first day, the male and female chicks were weighed and divided by the feather sexing method so that the average body weight of chicks was approximately equal in each pen. Treatments consisted of six groups (including control): group 1 had a basal diet and normal drinking water, group 2 had a basal diet and probiotics (PrimaLac®) in drinking water as recommended by the manufacturer, group 3 had a basal diet and 2 % yogurt in drinking water, group 4 had a basal diet and 4 % yogurt in drinking water, group 5 had a basal diet and 2 % kefir in drinking water, and group 6 had a basal diet and 4 % kefir in drinking water. Chemical and microbiological characteristics of kefir and yogurt were measured after each production. The results showed that 4 % kefir, yogurt, and probiotic at the recommend level in water improved body weight gain, feed intake, and feed conversion ratio compared with other groups (P<0.05). The results indicated that treatment had a significant effect on the carcass yield, intestinal length, thigh yield, and abdominal fat in male and female chickens (P<0.05). There were no effects on total bacteria population but the lactobacilli and coliform bacteria populations showed increasing and decreasing trends, respectively, with 4 % kefir, yogurt, and probiotic supplementation at 28 and 42 d (P<0.05). In addition, blood glucose and total protein increased when using a high levels of kefir, yogurt, and probiotic in water, while cholesterol and LDL (low-density lipoprotein) concentrations were lower in 4 % kefir, yogurt, and probiotic at the recommended level. Consequently, the results of this study showed that the use of 4 % kefir, yogurt, and probiotic at recommended level in water had beneficial effects on the growth performance, intestinal bacteria population, and blood biochemical parameters in male and female broiler chickens.