This trial was conducted to evaluate the effects of dietary supplementation of phytogenic product containing an equal mixture of thymol and carvacrol at 4 levels (0, 60, 100, and 200 mg/kg of diet) on performance, antioxidant enzyme activities, fatty acid composition, digestive enzyme activities, and immune response in broiler chickens. Each of the 4 diets was fed to 5 replicates of 12 chicks each from d 0 to 42. The inclusion of thymol + carvacrol linearly decreased (P < 0.05) feed intake, but the highest (P < 0.05) BW gain (ADG) and feed efficiency was observed in broilers offered 200 mg/kg of phytogenic product. The phytogenic product linearly increased (P < 0.05) superoxide dismutase and glutathione peroxidase activities and decreased (P < 0.05) malondialdehyde level in thigh muscle at d 42 and serum and liver at d 24 and 42. Total saturated fatty acids were depressed (P < 0.05) and total polyunsaturated fatty acid and n-6 were linearly increased (P < 0.05) in serum and thigh by the inclusion of phytogenic product compared with the control diet. Supplementation with thymol + carvacrol also increased intestinal and pancreatic trypsin, lipase, and protease activities in 24-d-old (linear, P < 0.05) but not in 42-d-old birds. Thymol + carvacrol modified (linear, P < 0.05) immune response by increasing hypersensitivity response, total and IgG anti-sheep red blood cell titers, and decreasing heterophil to lymphocyte ratio compared with the control group. However, hematological parameters and lymphoid organ weight were not affected by thymol + carvacrol. Thus, feed supplementation with thymol + carvacrol enhanced performance, increased antioxidant enzyme activities, retarded lipid oxidation, enhanced digestive enzyme activities, and improved immune response of broilers.

No abstract

The ban on the use of antibiotics as growth promoters has stimulated the search for alternative feed supplements in poultry production. The active principles of thyme essential oil act as a digestibility enhancer, balancing the gut microbial ecosystem and stimulating the secretion of endogenous digestive enzymes and thus improving growth performance in poultry (Lovkova et al., 2001;Williams and Losa, 2001). A study was performed to investigate the effects of thyme essential oil (TEO) on performance, carcass characteristics, some blood parameters and ileal microflora of Japanese quail. This study lasted 35 days of age. One hundred and fifty day-old male Japanese quail chicks in a completely randomized design with two treatments (with or without 1 g/kg TEO) and five replicates of 15 birds each were used. All parameters were measured at the end of the experiment. The supplementation of TEO significantly (P＜0. 05) increased live body weight and relative weights of carcass and breast, lowered serum triglyceride, total cholesterol and glucose and improved ileal microflora. It was concluded that the addition of 1 g/kg TEO might offer some beneficial effects on Japanese quail to increase live body weight and improve some blood parameters and gut miroflora.

This study was conducted to evaluate the effects of thymol + carvacrol as plant essential oils on performance, digesta viscosity and some blood metabolites of broilers fed diets supplemented with carboxy methyl cellulose (CMC) and/or thymol+carvacrol. In a completely randomized design with a 2 × 3 factorial arrangement, two levels of CMC (0% and 2%) and three levels of thymol+carvacrol (0, 100 and 200 mg/kg) were used. Each of the six dietary treatments was fed to five replicate pens of 12 birds each from 0 to 42 days of age. Body weight gain (BWG), feed intake, feed conversion ratio (FCR), intestinal digesta viscosity and pH, plasma lipids and some blood metabolites were recorded. The inclusion of 2% CMC decreased (p < 0.05) BWG by 2.2% and increased FCR by 2.3% at 42 days of age. Carboxy methyl cellulose significantly increased the digesta viscosity and decreased serum total cholesterol, but had no significant effect on triglyceride, pH, HDL, LDL and other blood metabolites measured in this experiment. Thymol+carvacrol had no effect on feed intake, but significantly increased (p < 0.05) BWG from 1 to 42 days of age and improved FCR (p < 0.05) by the addition of 100 and 200 mg/kg thymol+carvacrol respectively. Inclusion of thymol+carvacrol at levels of 100 and 200 mg/kg in the diets decreased digesta viscosity and serum total cholesterol (p < 0.05) and also increased AST at a 200 mg/kg thymol+carvacrol without any effect on creatine kinase (CK). Thymol+carvacrol significantly increased total protein (TP), albumin and globulin (p < 0.05). In conclusion, CMC at an inclusion level of 2% of diet increased digesta viscosity and reduced growth performance. However, thymol+carvacrol decreased digesta viscosity and consequently improved the performance of broilers fed the CMC-based diet. Therefore, thymol+carvacrol addition to viscose-based diets might be helpful to alleviate the negative effects of viscous compounds in poultry diets.

An experiment was conducted to investigate the effect of a prebiotic on performance of partridge. The experiment was carried out with a total of eighty-day-old male Chukar partridge (Alectoris chukar chukar) chicks in a completely randomized design. The dietary treatments consisted of a control and an experimental treatment, and each treatment was replicated four times with 10 chicks per replicate. The experimental period lasted 16 weeks with a starter period (0-8 weeks) and a grower period (9-16 weeks). The control group was fed the basal diet, while the experimental group was fed the basal diet supplemented with 0.18% prebiotic Aspergillus meal in each period. Performance parameters included body weight gain, cumulative feed consumption and cumulative FCR and were recorded at biweekly intervals. Carcass characteristics and blood parameters were measured at the end of the experiment (week 16). Although the results showed that prebiotic had no significant effect on body weight gain and cumulative feed conversion ratio; however, the supplementation of Aspergillus meal significantly (p < 0.05) decreased cumulative feed consumption. Also prebiotic significantly increased percentages of breast and gastrointestinal tract, decreased percentage of back-neck, decreased blood triglyceride and total cholesterol content and increased blood calcium content. From this study, it was concluded that dietary supplementation of 0.18% Aspergillus meal might offer beneficial effects on partridge feed consumption, carcass quality and blood cholesterol.