Effect of the Addition of Saccharomyces Cerevisiae Yeast Cell Walls to Diets with Mycotoxins on the Performance and Immune Responses of Broilers

Abstract

This study was conducted to evaluate the effect of Saccharomyces cerevisiae yeast cell walls (YCWs) in diets with low doses of aflatoxin B1 (AFB1) and ochratoxin A (OTA), alone or in combination, on broiler performance and immune response. A total of 210 male broilers aged 1-21 days were used. Broilers were completely randomized into seven treatments with five replicates of six broilers each, as follows: 1) control diet; 2) control + 350 µg/kg AFB1; 3) Control + 350 µg/kg OTA; 4) Control + 350 µg/kg AFB1 and 350 µg/kg OTA; 5) Control + 350 µg/kg AFB1 and 1.5 kg/ton YCW; 6) control + 350 µg/kg OTA and 1.5 kg/ton YCW; 7) control + 350 µg/kg AFB1, 350 µg/kg OTA, and 1.5 kg/ton YCW. The broilers were housed under environmentally controlled conditions in Petersime battery cages. Weight gain, feed intake, and feed conversion index were measured. The relative weights of the thymus, spleen, and bursa of Fabricius (BF) were evaluated. The local immune response was assessed by quantifying the level of intestinal immunoglobulin A (IgA). The cellular immune response was evaluated using a delayed hypersensitivity test. Hemograms and blood cell counts were also performed. The results showed that mycotoxins decreased performance and reduced the immune response (p<0.05) of broilers. Weight gain and feed conversion improved in the groups receiving YCWs. The YCWs increased (p<0.05) intestinal IgAs and the cellular immune response (p<0.05). The addition of YCWs also affected the relative weight of the thymus, spleen, and BF (p<0.05), and the leukocyte, lymphocyte, and heterophil counts (p<0.05). The addition of YCWs can be an alternative to counterage the negative effect of low doses of AFB1 and OTA in broilers diets.

Keywords: Saccharomyces cerevisiae; mycotoxins; yeast cell walls.

Fig. 1.

Histological sections from the aflatoxin B1 (AFB) treatment. 1) Liver with fibrosis (gray arrow), 2) Liver bile duct hyperplasia (black arrows), and 3) Liver fatty degeneration (white arrows) and 4) the bursa of Fabricius with lymphoid depletion (black arrows) are shown. 5) Kidney no microscopic morphological alterations.

Fig. 2.

Histological sections from the ochratoxin A (OTA) treatment. 1) Liver (Non Significants Changes), Bile duct without apparent pathological changes (white arrows), 2) spleen with mild lymphoid depletion (white arrows), central arteriola (black arrow), 3) thymus with apoptosis (white arrows), and 4) bursa of Fabricius with lymphoid depletion (black arrows) are shown.

Fig. 3.

Histological sections from the aflatoxin B + ochratoxin A (AFB + OTA) treatment. 1) Liver with bile duct hyperplasia (white arrows), 2) thymus with apoptosis (black arrows), 3) spleen with lymphoid depletion (white arrow), central arteriola (black arrow), and 4) bursa of Fabricius with lymphoid depletion (black arrow) and apoptosis (white arrows) are shown.