Effect of Inorganic Sulfate and Sulfur Amino Acids on Bone Mineralization in Broilers

Two experiments with a factorial arrangement of treatments were conducted to determine the effect of inorganic sulfate and sulfur amino acids (SAA) levels on bone mineralization and Ca excretion in broilers from 1 to 21 days of age. Experiment 1 included two levels of Ca (.6 and 1.0%), two sulfate sources [copper sulfate (CuSO4·5H2 O), and potassium sulfate (K2 S4 O)], and three sulfate levels (.024, .034, and .044%). Experiment 2 included two Ca levels (.6 and 1.0%), two CP levels (18 and 22%), and three SAA levels (.93, 1.23, and 1.53%). Body weight gain, feed:gain, feed consumption, and tibia variables were measured in both experiments. In Experiment 2, Ca retention was also assessed. In Experiment 1, birds fed potassium sulfate and .6% Ca gained significantly more weight than birds fed copper sulfate and 1.0% Ca, respectively. As sulfate level increased, tibia ash percentage increased and decreased linearly in birds fed copper sulfate and potassium sulfate, respectively (P < .012). In Experiment 2, birds fed 1.0% Ca, .93% SAA, and 22% CP performed better than the birds receiving the other levels. A low Ca level (.6%) was more detrimental for bone mineralization in birds fed 22% CP compared with birds fed 18% CP. There was no effect of SAA on tibia ash and Ca percentages. Fecal Ca excretion decreased linearly with SAA level (P < .01). The results suggest that inorganic sulfate from the potassium salt may adversely affect Ca deposition in bone. However, SAA supplementation up to 65% in excess of the requirement in starter broiler diets did not affect bone mineralization.