MITIGATING THE EFFECTS OF HALOFUGINONE ON SKIN STRENGTH BY FEEDING L-PROLINE TO BROILER CHICKEN

Two experiments were conducted to determine whether supplemental level s of L-proline in the diets of broiler chickens would mitigate the ski n weakening effect caused by continuous feeding of the anticoccidial h alofuginone. In Experiment 1, tensile strength and collagen levels in thigh apteria skin were determined at 21 and 42 d of age in male broil ers fed 0, .5, and 1% L-proline with either halofuginone (3 mg/kg) or salinomycin (61 mg/kg). In Experiment 2, the same measurements were ma de on female broilers receiving diets containing halofuginone and supp lemented with 0,.5, or 1% L-proline, 1% L-proline through 21 d of age, or 1% L-glutamic acid through 21 d of age, or a diet containing high L-proline feedstuffs (corn gluten meal and ring dried blood meal). In Experiment 1, dermis thickness of thigh apteria was measured in the ma les at Day 21. Skin strength was increased in male and female broilers fed halofuginone with addition of .5 and 1% L-proline, respectively, at 21 and 42 d of age. Continuous incorporation of synthetic L-proline into diets was shown to improve skin strength in females, whereas die ts formulated to contain high levels of L-proline from feedstuffs, 21- d feeding of L-proline, or L-glutamic acid did not increase skin stren gth.