کد مقاله : BIP-012

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Ali Asnaashari*, Morteza Youssefi and Amir A. Solati

Objective: This experiment was conducted to evaluate the effects of dietary inclusion of probiotic, symbiotic and phytobiotic on growth performance and immune system of broilers under heat stress. Material and methods: A total of 256 male day-old Hybrid Ross 308 were divided in a completely randomized design with 4*2 factorial arrangement consisting: eight treatments and four replicates. Dietary treatments were fed: 1) Control (without feed additives); 2) Control with probiotic (Primalac) (300mg/kg) ; 3) Control with symbiotic (Biomin IMBO) (1000 mg/kg) and 4) Control with phytobiotic (essential oils) (100 mg/kg) and heat treatments including: 1) normal heat and 2) 39₀С heat were used for 42-d. The traits including feed intake, weight gain and feed conversion ratio were measured weekly.

Antibody titer against with Gumbro disease was determined by ELISA Kit after 10 days of Gumbro vaccination. At 42 days of age, eight birds from each treatment were selected and then blood drained with wing vein to measure IgM nd IgG by ELISA Kits. Results: The results showed that average daily gain had significant difference between symbiotic supplementation diet and control at grower period (22-42 d), symbiotic supplementation diet had higher weight gain than the other treatments. Overall, the 42-d period was numerically different in symbiotic and phytobiotic supplementation diets. But, body beight gain were not affected by environmental temperature and interactions between dietary treatments and temperature. Also, antibody titer, IgM and IgG for the birds fed to experimental treatments were higher than the birds fed to control (P<0.001). But house environment temperature and interactions between dietary treatments and temperature on immunity system were not significant. Conclusion: Overall, the results showed that inclusion of growth promoters in broilers diet caused improvement in growth performance and immunity system.