Association of the Transsulfuration Pathway in Feather Follicle and Subcutaneous Tissue Development in Broiler Chickens

Plumage coverage of birds is involved in thermoregulation and plays an important role in energy utilization and as a result affects feed intake and feed efficiency. Feather growth and structure are important characteristics of the modern meat-type birds. Disruption of feather keratinization affects its development and growth. Cysteine is the most common amino acid in feathers and is synthesized from homocysteine through the transsulfuration pathway (TSP). We tested the direct involvement of cysteine in feather follicle development by either feeding a cysteine deficient diet or inhibiting cystathionine beta synthase (CBS) and cystathionine gamma lyase (CGL) with propargylglycine in meat-type birds. Both CBS and CGL catalyse the conversion of homocysteine to cysteine. There were no histological changes in the birds fed cysteine deficient diet at 10 days. However, birds that received the inhibitor treatment had reductions in epidermis thickness, and length and diameter of the primary follicle. However, at day 24, birds on the cysteine deficient diet had reduced epidermis thickness and also reduced primary feather follicle length. Feather follicle and subcutaneous tissue development can be affected by dietary amino acids therefore, proper functioning of the TSP is important for normal physiological processes of the bird.