Antioxidant Status, Blood Constituents and Immune Response of Broiler Chickens Fed Two Types of Diets with or without Different Concentrations of Active Yeast

Abstract

Probiotics, such as active yeasts, are widely used to enhance poultry production and reduce feeding costs. This study aimed to investigate the antioxidant and immune responses of broilers to different concentrations of active Saccharomyces cerevisiae (SC) when supplemented to two types of diets. A total of 216 1-day-old Arbor Acres unsexed chicks were used in a factorial design, involving two feeds (regular- versus low-density diet) and three concentrations of SC (0%, 0.02% and 0.04%). The results revealed that the low-density diet reduced the body weight and production index of broilers. The addition of SC improved the production index more than the control diet. Total antioxidant capacity (TAC), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and eosinophils were significantly higher in response to the regular-density diet than the low-density diet; however, phagocytic activity (PA), lymphocyte and lysozyme activity (LYS) were lower. Saccharomyces cerevisiae reduced ALT, AST, malondialdehyde (MAD) and TAC more than the standard set, but improved packed cell volume (PCV), hemoglobin (Hgb), red blood cells (RBCs), lymphocytes, monocytes, heterophils, phagocytic index (PI) and the immune response to Newcastle disease virus (NDV) and avian influenza (AI). In conclusion, supplementation of a regular- or low-density diet with SC at a concentration of 0.02% or 0.04% improved the antioxidant parameters, immune status and production index of broilers against stress and infectious agents.

Keywords: active yeast; antioxidant status; broilers; immune response; nutrient density.

Figure 1

Micrograph of bursa of Fabricious of broiler at day 38 of age stained with HandE (X40) to investigate the follicle diameter in different groups; the distance between two follicular polar as presented all groups by lines: (A) Broilers supplemented with 0.02% Saccharomyces cerevisiae;(B) broilers supplemented with 0.04% Saccharomyces cerevisiae. Moderate enhancement in the follicular diameter was detected in broilers supplemented with 0.04% Saccharomyces cerevisiae (B).

Figure 2

Micrograph of the thymus stained with HandE (X40) to explore the thymic cortical: medullary ratio.

Figure 3

Micrograph of the spleen stained with HandE (X40) of regular density diet presented normal splenic histology featuring splenic arteriole (thin arrow) with white and red pulp (thick arrow). All groups presented the normal splenic histology as the control.