Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2006.1250.1256MoghadamA. NouriPourrezaJ. SamieA. H.7200697The present experiment was carried out on 405 broiler chicks (Arian strain) over a period of two weeks (from 8 to 21 days of age) to investigate the effects of different levels of dietary citric acid and phosphorus on calcium and phosphorus requirements in broiler chicks and on their performance. The experiment was a 3 x 3 factorial one including three levels of zero, 1.5 and 3% citric acid as well as three levels of 0.3, 0.35 and 0.4%, respectively dietary phosphorus in a completely randomized design. Thus, 9 experimental diets were prepared, each of which was randomly administered to three groups of the chicks (three replications for each diet). The effects of different levels of citric acid and phosphorus as well as their interactive effects on body weight, daily feed consumption, feed conversion efficiency, feed/gain ratio, weight percentage of body parts, percentage of bone ash, calcium and phosphorus percentages in bone ash and plasma inorganic phosphorus and calcium were assessed and determined. The results showed that the effects of different levels of citric acid on body weight (p<0.05), feed consumption, calcium and phosphorus concentrations in bone ash and plasma (p<0.01) were significant but that they had no significant effects on bone ash percentage, feed conversion efficiency and feed/gain ratio. The effects of different levels of phosphorus on body weight, daily feed consumption, bone ash percentage, plasma calcium and phosphorus percentages (p<0.01) and bone ash phosphorus percentage (p<0.05) were significant while no significant effects were observed in the case of feed conversion efficiency, feed/gain ratio and plasma calcium. The interactive effects of citric acid and phosphorus on 21-day body weight, bone ash percentage (p<0.05), feed consumption, bone ash calcium percentage, bone ash phosphorus percentage (p<0.05), plasma phosphorus and calcium (p<0.01) were significant while they had no significant effects on other parameters measured. From the results obtained, it seems that citric acid plays a role in calcium and phosphorus utilized by poultry and may increase the absorption of these minerals.]]>Ahmed, S.H., A.T. Cantor, H. Johnson and A.Y. Robert,199064966971AOAC.,19901st Edn.,pp: 88pp: 88Baginski, E.S., S.S. Marie, W.L. Clark and B. Zak,1973464654Boling, S.D., M.W. Douglas, J.L. Snow,C.M. Parsons and D.H. Baker,20007913351337Boling, S.D., D.M. Webel, I. Mavromichalis, C.M. Parsons and D.H. Baker,200078682689Boling-Frankenbach, S.D., J.L. Snow, C.M. Parsons and D.H. Baker,200180783788Boling, S.D., M.W. Douglas, R.B. Shirley, J.L. Snow, A.B. Coreless and C.M. Parsons,200380175Broz, J., P. Oldale, A.H. Perrin-Voltz, G. Rychen, J. Schulze and C.S. Nunes,199435273280Carmer, S.G. and W.M. Walker,1985141926Frost, T.J. and D.A. Roland Sr.,199170963969Giesting, D.W. and R.A. Easter,19856012881294LeeRussel, M.C.,1992Leeson, S. and J.D. Summers,20014th Edn.,Liu, J., D.W. Bollinger and D.R. Ledoux. and T.L. Veum,199876808813Perney, K.M., A.H. Cantor, M.L. Straw and K.L. Herkelman,19937221062114SAS Institute,19998th Edn.,Smith, O.B. and E. Kabaija,19856417131720Tietz, N.W.,1986pp: 583-584pp: 583-584