Chronic Exposure to the Fusarium Mycotoxin Deoxynivalenol: Impact on Performance, Immune Organ, and Intestinal Integrity of Slow-Growing Chickens

Abstract

This study investigates the long-term effects of deoxynivalenol (DON) consumption on avian growth performance, on the proliferation, apoptosis, and DNA damage of spleen cells, and on intestinal integrity. Two hundred and eight 5-day-old black-feathered Taiwan country chickens were fed diets containing 0, 2, 5, and 10 mg/kg of DON for 16 weeks. Body weight gain of male birds in the 2 mg/kg group was significantly lower than that in the 5 mg/kg group. At the end of trial, feeding DON-contaminated diets of 5 mg/kg resulted in heavier spleens. Moreover, the increase in DON induced cellular proliferation, apoptosis, and DNA damage signals in the spleen, the exception being female birds fed 10 mg/kg of DON showing reduced proliferation. Expression of claudin-5 was increased in jejunum of female birds fed 2 and 5 mg/kg of DON, whereas decreased expression levels were found in male birds. In conclusion, our results verified that DON may cause a disturbance to the immune system and alter the intestinal barrier in Taiwan country chickens, and may also lead to discrepancies in growth performances in a dose- and sex-dependent manner.

Keywords: chicken; deoxynivalenol; immunohistochemistry; intestine; long-term effects; spleen; tight junction.

Figure 1

The impact of deoxynivalenol (DON) on growth performance of Taiwan country chickens at different durations of exposure. Bars are presented as mean ± SD; d, wk: days or weeks of age; ** p < 0.01.

Figure 2

The impact of deoxynivalenol (DON) on relative weight (% body weight) of spleen in Taiwan country chickens at 16 weeks of age. Bars are presented as mean ± SD; * p < 0.05.

Figure 3

Effects of deoxynivalenol (DON) on spleen histopathology in Taiwan country chickens at 16 weeks of age. Hematoxylin-eosin staining of spleen sections in chickens fed with: (A) basal diet; (B) 2 mg DON/kg diet; (C,E) 5 mg DON/kg diet; and (D,F) 10 mg DON/kg diet. Magnification: (A–D) ×40; (E,F) ×100. Germinal centers are indicated by arrowheads.

Figure 4

Effects of deoxynivalenol (DON) on spleen proliferation, apoptosis, and DNA damage in Taiwan country chickens at 16 weeks of age: (A1–A4,C1–C4) represent spleen sections of immunohistochemical staining of PCNA and γ-H2AX, respectively; (B1–B4) indicate the TUNEL staining of apoptotic cells; (D1–D3) represent negative controls of PCNA, TUNEL assay, and γ-H2AX, respectively. Chickens were fed: (A1–C1) basal diet; (A2–C2) 2 mg DON/kg diet; (A3–C3) 5 mg DON/kg diet; and (A4–C4) 10 mg DON/kg diet; (E–G) respectively show the percentage of PCNA-, TUNEL-, and γ-H2AX-positive cells in different DON treatments. Magnification: ×400. Positive signals are indicated by magenta color and counterstained by hematoxylin. Bars are presented as mean ± SD; ^a–c groups without the same superscript differ significantly at p < 0.05; * p < 0.05.

Figure 5

Effects of deoxynivalenol (DON) on the intestinal morphology in Taiwan country chickens at 16 weeks of age. Frozen sections of ileum in chickens fed with: (A) basal diet; (B) 2 mg DON/kg diet; (C) 5 mg DON/kg diet; and (D) 10 mg DON/kg diet. Magnification: ×40. Marked difference was noticed in (C) as appeared by shortened villi in some male birds.

Figure 6

Western blot analysis of claudin-5 (CLDN5) expression in jejunum of Taiwan country chickens fed different levels of deoxynivalenol (DON) contaminated diets at 16 weeks of age. The upper panel illustrates a Western blot representative figure: 10 μg protein from intestinal homogenates were loaded in each lane. The expression of the proteins was estimated by densitometry after normalization with β-actin signal. The lower panel shows normalized CLDN5 expression. Bars are presented as mean ± SD; ^a,b groups without the same superscript differ significantly at p < 0.05.