RESUMO
BACKGROUND: The trend of using probiotic, prebiotic and their mixture as alternative feed additives which works as growth promoters in poultry diets to increase the productive performance and the immunity of the flock still have an importance consideration. So that the aim of this study is to estimate the impact of Bio-plus2B® (probiotic), Techno Mos® (prebiotic) or their mixture (synbiotic) on egg production, egg and shell quality, some blood metabolites and retention of nutrients between 28 and 40 weeks of age. The hens (ISA brown laying) were allocated randomly in 40 cages; 10 cages/treatment with two hens each. The treatments were the control (T1), T2 (Probiotic: 1 g Bio-plus2B® (Bacillus licheniformis plus Bacillus subtilis)/kg feed), T3 (Prebiotic: 1 g Techno Mos® (Mannanoligosaccarides (MOS) and 1,3 B-glucan) /kg feed) and T4 (Synbiotic: 1 g Bio-plus2B® plus 1 g Techno Mos®/ kg feed). RESULTS: Hen-day egg production% and mass were significantly increased (P < 0.05) with T2 and T4 treatments. The experimental treatments recorded an increase in albumen index, Haugh unit (P < 0.01), shell thickness (P < 0.05), the retention of crude protein (CP), crude fiber (CF) and ether extract (EE) (P < 0.05), plasma globulin, albumin and total protein (P < 0.001) versus to the untreated group, while egg weight was not affected. Synbiotic treatment showed a significant (P < 0.001) increase in shell calcium content. T3 and T4 treatments were significantly decreased plasma cholesterol (P < 0.001) and low density lipoprotein (LDL) (P < 0.05). Alanine transaminase (ALT) was significantly (P < 0.001) decreased and estradiol hormone was increased (P < 0.001) in the experimental groups versus to the control. CONCLUSIONS: It concluded that adding probiotic and/or prebiotic in the early age laying hens diets had beneficial effects for productivity with improving the egg shell thickness.