Naturally contaminated feed with low levels of fumonisins with anti-mycotoxin additive and its impact in the immune cells and blood variables in broiler chickens

Abstract

Ninety six one-day-old broiler chickens were used to evaluate the effect of feeding naturally contaminated rations with low levels of fumonisins (FBs) and the protective effect of a commercial anti-mycotoxin additive (AMA) on circulating and intestinal immune cells, blood biochemistry, hematological variables and biomarkers of FBs exposure. Birds were assigned in three groups: Negative control (NC), positive control (PC) containing low level (17 ppm) of FBs (FB1 + FB2) in feed, and PC with AMA at 0,2%  (AMA + PC). Blood was collected and used to quantify circulating leucocytes through flow cytometry, activity of aspartate transaminase (AST), gamma glutamyl transferase (GGT), alkaline phosphatase (ALP) and levels of uric acid (UA), total protein (TP), albumin (Alb), globulin (Glb), Alb:Glb ratio, total leucocytes count (TLC) and hematocrit (Ht), as well as free esphinganine to esphinogosine ratio (SA:SO). On day 3, FBs reduced circulating CD4+TCRVβ1- and CD8+CD28- lymphocytes in PC; reduced B Llymphocytes and increased Kul-MHCII+ in both PC and PC+AMA, and increased Kul+MHCII+ cells in PC+AMA birds. On day 7, circulating CD4+TCRVβ1+ and CD8-CD28+ and CD3+ in jejunum were increased only in PC, while CD4-TCRVβ1+ were increased in both PC and PC+AMA birds. FBs reduced TLC and Alb:Glb in both PC and PC+AMA birds after 14 days and only in PC after 28 days, while increased Glb after 14 days in both PC and PC+AMA. On day 28, FBs increased Alb:Glb and reduced Ht only in PC birds, increasing Alb levels and GGT activity in both PC and PC+AMA birds. Serum SA:SO was increased only in PC birds on day 28. These results showed that low levels of naturally occurring FBs could induce rapid immune alterations and impaired liver function and blood homeostasis, which may reflect in a reduction in the overall birds’ competence to respond to challenges.  Therefore, even if the regulatory standards of FBs are met, toxicity may occur and can be detected by sensitive markers. The use of an AMA was able to alleviate most of these effects.   Key words: Fumonisins, broiler chickens, flow cytometry, immunohistochemistry, anti-mycotoxin additive.