Transgenic chickens expressing beta-galactosidase hydrolyze lactose in the intestine

Abstract

Chickens do not possess the necessary enzymes to efficiently hydrolyze lactose into glucose and galactose. The bacterial enzyme beta-galactosidase can convert lactose into glucose and galactose. Transgenic chickens that carry the E. coli lacZ gene and express beta-galactosidase could potentially utilize lactose as an energy source. The objective of this study was to determine the ability of the transgenic chicken small intestinal mucosa to hydrolyze lactose into glucose and galactose. Lactase activity was examined in the intestinal muscosa from wild-type chickens and two lines of chickens that carry the lacZ gene and express beta-galactosidase. Lactase activity was significantly higher in both transgenic lines compared with wild-type birds (P < 0.05). The presence of the beta-galactosidase enzyme was revealed by X-gal staining in the intestine of transgenic chickens, whereas it was not present in the wild-type chickens. Overall, it appears that inserting the lacZ gene, which encodes beta-galactosidase, has resulted in a chicken that can utilize lactose as an energy source. This study demonstrates that transgenic technology can be used to modify nutrient utilization in domestic poultry.