Performance, serum biochemical responses, and gene expression of intestinal folate transporters of young and older laying hens in response to dietary folic acid supplementation and challenge with Escherichia coli lipopolysaccharide

ABSTRACT The present study was conducted to investigate the effects of dietary folic acid (FA) supplementation on performance, serum biochemical indices, and mRNA abundance of intestinal folate transporters in young and older laying hens after acute lipopolysaccharide (LPS) challenge. Two experiments were conducted separately involving 48 Shaver White young laying hens (24 wk of age) in experiment 1 and 48 Shaver White older laying hens (58 wk of age) in experiment 2. Birds were fed 2 diets in a complete randomized design. The diets were wheat-soybean meal based, with or without supplemental 4 mg of FA/kg of diet. Birds were fed for 8 wk, during which time feed consumption and egg production were monitored. At the end of each feeding experiment, 6 hens from each dietary treatment were injected intravenously with 8 mg/kg of BW of either Escherichia coli LPS or sterile saline. Four hours after injection, blood and intestinal samples were collected for further analysis. Compared with the control, dietary FA supplementation increased egg weight and egg mass and decreased serum glucose levels in the young laying hens, and reduced serum uric acid in the older laying hens (P