Aflatoxicosis in Chickens (Gallus gallus): An Example of Hormesis?

Abstract

Poultry has commonly been considered highly susceptible to aflatoxins. However, among domestic fowl there is wide variability in specific species sensitivity to these mycotoxins. Comparative toxicological studies in avian species have shown that ducklings and turkey poults are the most sensitive species to aflatoxins, quails show intermediate sensitivity, whereas chickens are the most resistant. Hormesis is a dose-response phenomenon characterized by low-dose stimulation and high-dose inhibition. The low-dose stimulation is typically maximal at only about 30 to 60% greater than controls. Hormesis has been noted in regards to changes in body weight in numerous studies, including those performed for the US National Toxicology Program, with over 50 chemicals. The present paper assesses how relatively low levels of aflatoxin consumption in feed may affect the growth rate of chickens. In general, multiple independent investigations have shown that such aflatoxin consumption affects growth in a hormetic-like biphasic manner with a low dose stimulation and a high dose inhibition. Such observations were then generalized to other toxic agents and animal models, suggesting that low doses of stressor agents induce adaptive responses as reflected in accelerated growth rates. The implications of such hormetic dose responses are briefly discussed.

Biochemical and Histopathological Study of Aflatoxicosis on Ross 308 Broiler Chicks

“…The results of the present study do not support this biphasic proposal of Diaz et al (2008). Although at low doses (0.5 and 1.0 mg AFB 1 /kg of feed) there was no significant reduction, the body weights also did not increase compared with those in the control group until the end of the experiment (21 DPF).…”

“…Diaz et al (2008) proposed a biphasic nature (hormesis) of aflatoxins on the broiler's weight gain, i.e. improvement at low doses (0.625 mg/kg and 1.25 mg/kg) and reduction at high doses (2.5 mg/kg and 5.0 mg/kg).…”

The effects of aflatoxin B1 and silymarin-containing milk thistle seeds on ileal morphology and digestibility in broiler chickens

“…Currently, it seems that this plant can be referred to AFB1 absorbent on apparent ileal digestibility in broiler chicks. Diaz et al 23 reported that low levels of AFB1 in the diet did not affect DM and N digestibility in birds. Verma et al 24 reported a reduction in net protein utilization and AMEn when 1 to 2 mg kg -1 of AFB1 was fed to broiler chicks.…”

Aflatoxin in Agricultural Commodities and Herbal Medicine

“…Poultry are highly susceptible to aflatoxin contamination (Diaz, Calabrese, & Blain, 2008;Souza, Vilar, Stamford, Bastos, & Filho, 2008). Aflatoxins can have severe effect on body weight, poultry organism, particularly liver and kidney and renal malfunction of laying hens Valdivia, et al, 2010).…”