Effects of licorice extract, probiotic, toxin binder and poultry litter biochar on performance, immune function, blood indices and liver histopathology of broilers exposed to aflatoxin-B1

Abstract

Probiotics, toxin binders, and plant extracts improve health and immunity of broiler chickens exposed to aflatoxin. The effects of licorice extract (LE), Protexin probiotic, toxin binder (Agrabound), and poultry litter biochar (PLB) in experimental aflatoxicosis were evaluated. In a completely randomized design, 504 broiler chickens were allotted to 7 treatments and 6 replicates with 12 broiler chickens in each. The experimental groups were as follows: T1) basal diet (B) without any feed additive or aflatoxin B₁ (AFB₁); T2) B + 0.5 mg AFB₁/kg; T3) T2 + 3 g LE/kg; T4) T2 + 6 g LE/kg; T5) T2 + 0.5 g Protexin/kg; T6) T2 + 1 g toxin binder/kg, and T7) T2 + 5 g/kg PLB. Broiler chickens fed AFB diet (T2) had lower body weight gain at the end of grower period and higher feed conversion ratio at the end of the finisher period, whereas inclusion of LE, probiotic, toxin binder, or PLB restores body weight of broiler chickens to that of the control group. Aflatoxicosis decreased total protein, TG, albumin, Ca, and P concentrations and greater uric acid concentration in broiler chickens as compared with the control group (P < 0.05). As compared with the T2 group, inclusion of 3 mg LE/kg increased serum total protein; inclusion of 3 mg LE/kg, probiotic, and toxin binder increased TG; inclusion of 3 and 6 mg LE/kg, probiotic, and PLB increased serum albumin; and the whole additive decreased serum uric acid of broiler chickens comparing with the control group. Lymphocyte percentage, avian influenza antibody titer, thymus relative weight, and immune response to phytohemagglutinin were decreased in the T2 group, whereas heterophil percentage and heterophil-to-lymphocyte ratio were increased (P < 0.05). Aflatoxicosis increased breast meat malondialdehyde concentration, liver enzymes activities, and number of fat vacuoles (P < 0.05). As compared with the T2 group, all of the additives lowered alkaline phosphatase, aspartate aminotransferase, and alanine transaminase activities, breast meat malondialdehyde concentration, and liver pathological damages (P < 0.05). It can be concluded that all of the additives are capable to decrease the negative impact of AFB₁ on broiler chickens' performance, blood indices, and immunity.

Keywords: adsorbents; aflatoxin; broiler; medicinal herb; performance.

Figure 1

Hepatic histomorphology and histopathology from various groups of experimental broilers. The liver sections were stained with hematoxylin and eosin (100× magnification). 2- Control = basal diet, AFB = basal diet + 0.5 mg/kg aflatoxin B₁, LE3 = basal diet + AFB₁ + 3 g/kg licorice extract, LE6 = basal diet + AFB₁ + 6 g/kg licorice extract, PRO = basal diet + AFB₁ + 0.5 g/kg Protexin probiotic, TXB = basal diet + AFB₁ + 1 g/kg toxin binder, and PLB = basal diet + AFB₁ + 5 g/kg poultry litter biochar. The values are least square means of the 6 replicates in each treatment. Abbreviations: BN, black nodules; HD, high-density nodes; PF, peripheral fibrosis.