The focus on maximizing productivity, production efficiency, and profitability led to the development of intensive animal husbandry conditions. In this case, many diseases were outbreak, and therefore, for controlling of them and enhance performance of farm animals, using of chemical substances such as antibiotics was inevitable. The use of antibiotics as growth promoters (AGPs) in poultry production began from several years ago. They were added to diets growth stimulation. The usage of AGPs is possibly an important factor that promotes the emergence of antibiotic resistant microorganisms in veterinary and human medicine. The use of AGPs has been banned in some countries. Removal of antibiotics from the diet may negatively affect profitability of the animals. Therefore, the feed industry will have to research alternatives instead of antibiotics (15). Various aromatic plants and spices as well as fruits constitute valuable phytogenic sources. The Pistacia (genus) plant is known for its medicinal property. The plant species Pistacia Atlantica available in western mountains of Iran and in Khuzestan, Ilam, Kermanshah, Lorestan provinces. The antimicrobial and antioxidant properties of the native species are known. Therefore, this study was conducted to evaluate the effect of wild pistachio leaves extract (WPLE) (Ethanolic, EtOH-H2O; 80%) on performance, cecal microbial population and immunity responses of broiler chickens.
Materials and Methods
241 days old (mixed sex) broiler chicks (Ross308 strain) were used in a completely randomized design in 5 treatments, with 4 replicates and 12 chicks per each replicate. Dietary treatment included: 1)positive control (PC, corn-soybean meal bases diet); 2) negative control (NC, positive control supplemented with 0.1% Flavomicine; 3) WPLE1 (positive control supplemented with 0.1 WPLE); 4) WPLE2 (positive control supplemented with 0.2 WPLE) and 5) WPLE3 (positive control supplemented with 0.3 WPLE).The chicks were fed a corn-soy meal based diet (isocaloric and isonitrogenous (2969.0 kcal/kg metabolizable energy, 21.30% crude protein in starter period (1-21 d) and 3081.0 kcal/kg metabolizable energy, 19.20% crude protein in grower period (22-42 d)) supplemented with different levels of WPLE and Flavomicine as on top. The diets were in mash form and formulated according to the NRC (1994) recommendations. Feed and water were provided ad libitum during the experiment. Feed intake (FI), body weight gain (BWG) andfeed conversion ratio (FCR) of birds in each pen was recorded weekly and calculated forstarter, grower and total phases for each bird. On day 42, two chicks per replicate were slaughtered and carcass characteristics were determined. Blood samples were collected from two birds per replicate to determine blood characteristics including cholesterol, triglycerides (TG), low density lipoprotein (LDL), high-density lipoprotein (HDL) and very low density lipoprotein (VLDL)at the end of the experiment (42 d of age). On day 42, two chicks per replicate were selected randomly and killed aseptically and cecal content of each bird was pooled for determination of microbial population. The ileum digesta samples collected from two slaughtered birds and mixed with distilled water (1:10) and vortexed vigorously and pH was measured using a standard pH meter. For determination of immune response, at 21 and 35 d of age, 1 mL of 25% sheep red blood cell (SRBC) solution was injected into their breast muscle of 2 chicks per replicate and blood samples were collected from brachial vein of the birds 7 d after each injection.
Results and Discussion
The results of this experiment showed that FI and BWG were not affected by antibiotic and WPLE in starter, grower and total phase (P>0.05). FCR was increased significantly in starter by addition of feed additives (WPLE and flavomicine). Means by non-significant differences in this study, maybe due to normal rearing condition. Researcher believed that plant secondary metabolite can exert their positive effects on critical condition. There were no significant differences in immunity and carcass parameters (P>0.05).TG and VLDL content of broiler serum were lower in WPLE2 and WPLE3 groups rather than PC. Dietary treatments did not affected Coliform population but increased Lactobacillus and decreased Escherichia coli population of cecal content significantly (P<0.05). The antibacterial properties of plant extracts could be attributed mainly to their phenolic components and their mechanisms of action on the microbial cell. A possible explanation for the stimulatory effect of polyphenolic compounds on beneficial bacterial growth is that some microorganisms are able touse these compounds as nutritional substrates. In the particular case of lactobacilli, these bacteria possess the ability to metabolize phenolic compounds supplying energy to cells and positively affecting the bacterial metabolism. The pH of ileal digesta was decreased significantly in 0.2 and 0.3% of WPLE (P<0.05). Increasing lactobacilli bacteria population can decrease pH of gut digesta.
The results of this experiment suggest that WPLE can increase population of beneficial bacteria and decrease pathogen bacteria in cecal content and can lowering pH of ileal digesta.