- 1a Department of Human Nutrition, Faculty of Food Technology , University of Agriculture , Krakow , Poland.
- 2b Department of Animal Nutrition and Feed Science , National Research Institute of Animal Production , Krakow , Poland.
- 3c Department of Biochemistry and Molecular Biology , Medical Centre for Postgraduate Education , Warszawa , Poland.
- 4d Department of Pathomorphology , Jagiellonian University Medical College , Krakow , Poland.
- 5e Department of Medical Biochemistry , Jagiellonian University Medical College , Krakow , Poland.
Abstract
The
objective of this research were to investigate the effect of a
conjugated linoleic acid (CLA)-enriched diet on Isa Brown laying hen
health status and to provide a comprehensive analysis of changes in
blood parameters, liver morphology and selected hepatic gene expression.
Hens were allocated to the control and experimental group (diet
enriched with 0.75% CLA) for a total period of 4 m. At the end of the
experiment half of the hens from each group were slaughtered for
analyses. The remaining hens were transferred to an organic farm for the
next 5 m and fed on the diet without CLA supplementation. The
CLA-enriched diet resulted in significant changes in blood and serum
parameters; specifically, haematocrit (HCT), mean corpuscular volume
(MCV) and white blood cells (WBC) count were decreased compared to the
control. The total cholesterol (TC) was not significantly affected while
the triacylglycerol's (TG) concentration was elevated. The activity of
alanine aminotransferase (ALT) was significantly increased in the
CLA-supplemented group, while aspartate aminotransferase (AST) showed an
increasing tendency. Liver biopsies showed pathological changes
classified as non-alcoholic fatty liver disease (NAFLD). Additionally,
the expression of hepatic genes involved in fatty acids synthesis (ME1,
ACLY, ACC, FASN, SCD1), oxidation (CPT1α, PPARA), detoxification
processes (Cytochrome P450, CYP, Flavin-containing monooxygenase, FMO3),
oxidative stress (NOX4, XbP1) and inflammation (IL6, TNFα) were
elevated. Cessation of CLA supplementation for 5 m of organic farming
resulted in normalisation of blood and hepatic parameters to the levels
observed in control hens. The results of this study indicate that
dietary CLA triggers an integrated stress response in laying hens and
activates mechanisms involved in liver detoxification.
