Enantioselective Characteristics and Montmorillonite-Mediated Removal Effects of α-Hexachlorocyclohexane in Laying Hens

Abstract

α-Hexachlorocyclohexane (α-HCH) is a chiral organochlorine pesticide that is often ubiquitously detected in various environmental matrices and may be absorbed by the human body via food consumption, with serious detriments to human health. In this study, enantioselective degradation kinetics and residues of α-HCH in laying hens were investigated after a single dose of exposure to the pesticide, whereas enantioselectivity and residues of α-HCH in eggs, droppings, and various tissues were investigated after long-term exposure. Meanwhile, montmorillonite (MMT), a feed additive with high capacity of adsorption, was investigated for its ability to remove α-HCH from laying hens. Most non-brain tissues enantioselectively accumulated (-)-α-HCH, while (+)-α-HCH was preferentially accumulated in the brain. The enantiomer fractions (EFs) in most tissues gradually decreased, implying continuous depletion of (+)-α-HCH in laying hens. After 30 days of exposure and 31 days of elimination, the concentration of α-HCH in eggs and tissues of laying hens with MMT-containing feed was lower than that with MMT-free feed, indicating the removal effects of MMT for α-HCH in laying hens. The findings presented herein suggest that modified MMT may potentially be useful in reducing the enrichment of α-HCH in laying hens and eggs, thus lowering the risk of human intake of α-HCH.

Absorption, Distribution, Metabolism, and in Vitro Digestion of Beta-Cypermethrin in Laying Hens

“…During depuration, t 1/2 of beta-CP in egg yolks was only 3.56 days compared with t 1/2 of α-hexabromocyclododecane (17.4 days) 32 and αhexachlorocyclohexane (6.71 days). 30 This revealed that beta-CP was not persistent in egg yolks, while beta-CP was more slowly depurated after continuous exposure than after single exposure. 29 The maximum concentration of beta-CP was 4.8 ng/g in egg yolks on the 10th day, below the maximum residue limit (MRL, 50 ng/g) allowed in eggs for the European Union and the United States.…”

“…Unlike persistent organochlorine pesticide and other chemicals, , concentrations of beta-CP in egg yolks rapidly achieved a balanced state at the fifth day. During depuration, t 1/2 of beta-CP in egg yolks was only 3.56 days compared with t 1/2 of α-hexabromocyclododecane (17.4 days) and α-hexachlorocyclohexane (6.71 days) . This revealed that beta-CP was not persistent in egg yolks, while beta-CP was more slowly depurated after continuous exposure than after single exposure .…”

“…Concentration trends of beta-CP and its three metabolites ( trans / cis -DCCA and 3-PBA) in egg whites and egg yolks are depicted in Figure B. Unlike persistent organochlorine pesticide and other chemicals, , concentrations of beta-CP in egg yolks rapidly achieved a balanced state at the fifth day. During depuration, t 1/2 of beta-CP in egg yolks was only 3.56 days compared with t 1/2 of α-hexabromocyclododecane (17.4 days) and α-hexachlorocyclohexane (6.71 days) .…”