عنوان مقاله [English]
Introduction During decades, growth rate of broiler chickens was increased more than 4 times whereas growth rate of cardiovascular and respiratory tracts did not increase as muscle growth rate. Imbalance between oxygen consuming orangs and oxygen supplying organs led to increase metabolic disorders like ascites in broiler chickens. Low oxygen supplementation is the important factor in ascites syndrome by reducing arterial oxygen pressure and increasing pulmonary artery pressure. Increased pulmonary artery pressure led to hypertrophy of cardiac right ventricle and finally ascites incidence in broiler chickens during cold environment condition.
Antibiotics as growth promoters in poultry feed are posing serious health risks to human health, because of their residual effects in poultry meat and eggs, as well as result pathogens develop resistance to antibiotics. Currently, poultry scientists are challenged to find out alternatives to antibiotic growth promoters with no side effects for poultry that could be more or as effective against harmful microorganisms in the gastrointestinal tract and to stimulate the growth by increasing the efficiency of feed utilization and to enhance the immunity. Regarding to this subject, supplementing the dietary herbs or plant extracts would stimulate the productive performance of poultry. One of the most frequently consumed herbal remedies available today is the hyssop preparations prepared from Hyssopus officinalis (L) which is gaining increased importance as a minty flavor, condiment and spices in food industries as well. The GC and GC-MS analysis of the essential oil led to the identification of 21 compounds representing 95.6% of the oil, comprising seven monoterpene hydrocarbons (32.3%), five oxygenated monoterpenes (60.5%), one phenol (0.2%) and six sesquiterpene hydrocarbons (0.35%). The major constituents of the camphorous predominant monoterpenes of the oil were pinocamphone (49.1%) >β-pinene (18.4%). According to the results of the studies, hyssop extract showed much weaker antioxidant activity as compared to the rosemary, sage, and thyme extracts in different methods of antioxidant evaluations. The aim of this study was comparing the effects of Hyssopus Officinalis powder, Virginiamycin antibiotic and Aspirin on performance, blood metabolites, carcass parameters and ileum microbial population of broiler chickens which subjected to cold stress were studied.
Materials and Methods In a completely randomized design, a total of 500 male Ross-308 broiler chickens were allocated to 5 treatments with 5 replicates and 20 birds in each. Dietary treatment consisted of: 1) control, 2 and 3) basal diet plus 300 g/ton Virginiamycin or Aspirin respectively and 4 and 5) basal diet containing 0.5 or one percent Hyssopus, respectively. The diets were formulated to meet the requirements of broilers as established by the Ross 308 broilers feeding guide in starter (1-11 d), grower (12-25 d) and finisher (26-42 d). The birds were kept under conventional conditions for vaccination, temperature, ventilation, and lighting based on Ross catalogue recommendations. Standard management practices of commercial broiler production were applied. The broiler diets were formulated based on standardized ileal digestible amino acids and other requirements were obtained from Ross catalogue recommendations. Broiler chicken performance (feed intake, body weight gain, feed conversion efficiency, total and ascytic mortality and European production efficiency factor), erythrocyte osmotic fragility (EOF), blood cell count and blood metabolites including triglyceride, total cholesterol, HDL and LDL Cholesterol were measured at the 21 and 42 d of age. Carcass and abdominal fat percentage were calculated. Finally population of Lactobacillus and Escherichia coli of ileum were detected.
Results and Discussion As compared to control, inclusion of 1 percent Hyssopus increased feed intake (P < 0.05). Addition of Hyssopus and antibiotic increased weight gain, EPEF and decreased FCR compared to control and aspirin groups. Addition of one percent Hyssopus decreased red blood cell count, erythrocyte osmotic fragility (EOF) and heterophil percentage at 21 and 42 d of age as compared to control (P < 0.05). Escherichia coli population was reduced by antibiotic and one percent Hyssopus inclusion into broiler’ diet. Dietary treatments had no effect on WBC count, lymphocyte percentage, heterophil to lymphocyte ratio, serum total cholesterol, HDL- and LDL-cholesterol and urea concentration of broiler chickens at 21 and 42 d of age, carcass, and thigh meat and abdominal fat percentages at 42 d of age (P > 0.05) whereas broiler chickens fed diet containing 0.5 and 1 % hyssopus powder had higher breast meat percentage.
Conclusion In conclusion addition of aspirin or Hyssopus powder improved broiler chicken’s performance and decreased mortality due to ascites and heterophile to lymphocyte ratio in cold condition. Virginiamycin improved broiler chickens body weight gain in cold condition but due to probable drug resistance, it may suggest that Hyssopus supplementation in broiler diet as a good replacement for antibiotic in cold stress.