The effects of manganese, biotin, and choline on hexosamine and hydroxyproline content as related to leg weakness. 
Three experiments were conducted with day-old broiler chicks to determine the effects of dietary choline, biotin, and manganese on cartilage hexosamine and hydroxyproline content.  The incidence of leg weakness was 75% or higher on all basal diets.  The levels of supplementation found to minimize leg weakness were 1540 mg choline chloride/kg diet, .2 mg biotin/kg diet, and 100 mg manganese/kg diet.  The levels required to maintain normal epiphyseal cartilage hexosamine content were 385 mg of choline chloride, .05 mg of biotin, and 25 mg of manganese/kg of diet.  Substantially higher levels of nutrients were needed to reduce the incidence of leg weakness.  Only with manganese supplementation was the incidence of leg weakness significantly reduced at the level of supplementation required for normal hexosamine content.  Hydroxyproline content was not affected by varying the levels of supplemental choline, biotin, or manganese.