The effects of probiotics, prebiotics and synbiotics on gut flora, immune function and blood characteristics of broilers

Abstract

Abstract The microbial populations in the gastrointestinal tracts of poultry play an important role in normal digestive processes and in maintaining animal health. The purpose of this study was to evaluate the effects of probiotics, prebiotics and synbiotics on the growth parameters, gut ecosystem, histology and immune function. In this study, four experiments one in vitro and three in vivo were conducted using specific pathogen free (SPF) and Hubbard broiler chickens. The first experiment was designed to determine the influence of inulin as an effective prebiotic on lactic acid bacteria (LAB) strains, and to screen LAB for selection as a source of chicken probiotic. Eight strains of LAB were isolated from chicken caeca and three strains from the Plymouth University culture collection were screened for potential probiotic properties for growth in inulin from Jerusalem artichoke (Helianthus tuberosus) and commercial inulin (Frutafit® HD, Netherlands). Lactobacillus animalis JCM 8692 strain isolated from chicken caeca showed the highest auto-aggregation and co-aggregation ability, resistance to acidity and bile salts, strong suppression of pathogens and ability to adhere to epithelial cells compared with other isolated strains. The second experiment was conducted to investigate the influence of commercial inulin and Jerusalem artichoke tubers as prebiotic supplementation on the diversity of the caecal microflora, jejunum histology and immune organ of SPF chickens. This investigation has found that inulin which was extracted from JA had a similar result when compared with commercial inulin and could be a suitable candidate for an inulin source in broiler diets. The third experiment was conducted to investigate the influence of Bactocell® (PRO1) and Lb. animalis (PRO2) as probiotic supplements on broiler chickens. EPEF was significantly increased in probiotic1 and probiotic2 compared with control (311.03, 309.87 and 260.06) respectively. Both types of probiotics supported the growth of chicks healthy and could be a suitable candidate as a source of probiotic in broiler diet. The fourth experiment was conducted to investigate the influence of dietary supplementation of a probiotic (Lb. animalis), a prebiotic JA tuber and a combination of both (Synbiotic) in broiler chickens. Growth performance was improved in all additive supplementation compared with the control group. EPEF was increased in probiotic, prebiotic and synbiotic compared with control (290.8±11.8, 300.9±3.86, 322.1±7.09 and 262.3±5.94) respectively. Beneficial bacteria in the guts of chicks fed probiotic, prebiotic and synbiotic was increased compared with chicks fed control diet. The diversity of microbial population in the gastrointestinal tract of chickens improved due to additives. The intestinal villus lengths and microvilli density was improved in all additives supplementation in comparison with control. Overall, it was concluded that probiotic, prebiotic and synbiotics can positively affect production performance and can improve the gut health.