Phytochemicals reduce aflatoxin-induced toxicity in chicken embryos

Authors: YIN, HSIN-BAI - University Of Connecticut; CHEN, CHI-HUNG - University Of Connecticut; DARRE, MICHAEL - University Of Connecticut; Donoghue, Ann - Annie; DONOGHUE, DAN - University Of Arkansas; VENKITANARAYANAN, KUMAR - University Of Connecticut

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/2017
Publication Date: 7/28/2017
Citation: Yin, H., Chen, C., Darre, M.J., Donoghue, A.M., Donoghue, D.J., Venkitanarayanan, K. 2017. Phytochemicals reduce aflatoxin-induced toxicity in chicken embryos. Poultry Science. 96(10):3725-3732. https://doi.org/10.3382/ps/pex190.
DOI: https://doi.org/10.3382/ps/pex190

Interpretive Summary: Aflatoxins (AF) are a group of toxic metabolites of Aspergillus flavus and A. parasiticus, which can frequently contaminate a variety of feed ingredients, including peanuts, corn, and cottonseed. Contamination of poultry feed with AF is a major concern to the poultry industry, since aflatoxicosis in chickens results in significant economic losses due to poor feed utilization, decreased body weight gain, reduced egg production and increased mortality. Furthermore, during egg formation, AF residues could be transferred from the laying hens to the fertilized eggs, thereby resulting in decreased embryo viability and hatchability, and causing several organ malformations. Currently, cost-effective and practical methods to prevent AF-induced embryotoxicity in chickens are currently limited. In the past decade, the use of phytochemicals has gained significant attention due to increasing concern over the safety of synthetic chemicals and emergence of antibiotic-resistant strains of microorganisms. This study investigated the efficacy of 2 generally recognized as safe phytochemicals, namely carvacrol (CR) and trans-cinnamaldehyde (TC), in protecting chicken embryos from AF-induced toxicity. Day-old embryonated eggs were injected with 50 ng or 75 ng AF with or without 0.1% CR or TC, followed by incubation in an incubator for 18 d. Relative embryo weight, yolk sac weight, tibia weight, tibia length, and mortality were recorded on d 18 of incubation. The effect of phytochemicals and methanol (diluent) on embryo viability was also determined. Both phytochemicals significantly decreased AF-induced toxicity in chicken embryos. At 75 ng of AF/egg, CR and TC increased the survival of chicken embryo by ~55%. Moreover, CR and TC increased relative embryo weight by ~3.3% and 17% when compared to eggs injected with 50 ng or 75 ng AF, respectively. The growth of embryos (tibia length and weight) was improved in phytochemical-treated embryos compared to those injected with AF alone. Phytochemical and methanol treatments did not adversely affect embryo survival, and other measured parameters as compared to the negative control. Results from this study demonstrate that CR and TC could reduce AF-induced toxicity in chicken embryos.

Technical Abstract: Aflatoxins (AF) are toxic metabolites produced by molds, Aspergillus flavus and Aspergillus parasiticus, which frequently contaminate poultry feed ingredients. Ingestion of AF-contaminated feed by chickens leads to deleterious effects, including decreased bird performance and reduced egg production. Moreover, AF residues in fertilized eggs result in huge economic losses by decreasing embryo viability and hatchability. This study investigated the efficacy of 2 generally recognized as safe phytochemicals, namely carvacrol (CR) and trans-cinnamaldehyde (TC), in protecting chicken embryos from AF-induced toxicity. Day-old embryonated eggs were injected with 50 ng or 75 ng AF with or without 0.1% CR or TC, followed by incubation in an incubator for 18 d. Relative embryo weight, yolk sac weight, tibia weight, tibia length, and mortality were recorded on d 18 of incubation. The effect of phytochemicals and methanol (diluent) on embryo viability was also determined. Each experiment had ten treatments with 15 eggs/treatment (n = 150 eggs/experiment) and each experiment was replicated 3 times. Both phytochemicals significantly decreased AF-induced toxicity in chicken embryos. At 75 ng of AF/egg, CR and TC increased the survival of chicken embryo by ~55%. Moreover, CR and TC increased relative embryo weight by ~3.3% and 17% when compared to eggs injected with 50 ng or 75 ng AF, respectively. The growth of embryos (tibia length and weight) was improved in phytochemical-treated embryos compared to those injected with AF alone (P < 0.05). Phytochemical and methanol treatments did not adversely affect embryo survival, and other measured parameters as compared to the negative control (P > 0.05). Results from this study demonstrate that CR and TC could reduce AF-induced toxicity in chicken embryos; however, additional studies are warranted to delineate the mechanistic basis behind this effect.