The Journal of Poultry Science (Apr 2003)
Effects of Amino Acid, Enzyme Mixture and Phytase Added to Low Protein and Low Phosphorus Diet on Performance and Excretion of Nitrogen and Phosphorus in Broilers.
Abstract
In the purpose to reducing excretion of nitrogen (N) and phosphorus (P) without the influence of the growth performances and abdominal fat in broilers, a feeding trial and balance test were conducted. Four diets were prepared. The control diets (C) contained 23% crude protein (CP) for 0 to 21 days of age and 19% CP for 22 to 49 days of age, respectively. In the second diets (L), CP were reduced to 19 and 16% for both phases and crystal amino acids were added to be 110% of requirements at both phases. In the third diets (LE), an enzyme mixture (cellulase, xylanase and pectinase) was added to L. In the fourth diets (LEP), non-phytate P were reduced to 0.32% and 0.28% for both phases, and phytase was added. Eight hundred one-day-old broiler chicks, equal number of male and female, were divided into 4 treatments and given free access to one of the diets for 49 days of age, and body weight (BW), feed intake and mortality were recorded. At the end of experiment, 50 chicks per each treatment were slaughtered by bleeding through a jugular vein and eviscerated for the determination of abdominal fat. Using another 10 male broiler chicks per each treatment, excretion of dry matter (DM), N and P were determined by the balance test. There were no significant differences in BW gain, feed intake, feed conversion ratio and mortality among four treatments. Abdominal fat of broilers fed L was significantly heavier than that of other three treatments, and no significant differences were found in abdominal fat among other three treatments. Excretion of DM and N in L, LE and LEP decreased to 91, 84 and 82%, and 73, 70 and 70% of C, respectively. Excretion of P of broilers fed LEP decreased to a half of other three treatments, and there were no differences in P excretion among other three treatments.
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