Influence of age on net energy and dietary phytase supplementation on the standardized ileal digestibility of amino acids of palm kernel meal for broiler chickens.

The aim of this study is to evaluate the influence of age on net energy and dietary phytase supplementation on the standardized ileal digestibility (SID) of amino acids of palm kernel meal (PKM). To determine the SID, A total of 162 12-day-old and 72 32-day-old male Arbor Acres chickens were divided into three groups (D0, D1 and D2). For the net energy a total of 72 11- and 31-day-old broiler chickens were divided into two groups (R1 and R2). Each group consisted of six repetitions and was fed its respective ration. The group D0 received a diet without nitrogen, then group D1 received an experimental diet with PKM as the sole nitrogen source, and finally group D2 received a diet without mineral phosphorus while supplemented with 1,000 FTU phytase/kg diet. For net energy trial, group R1 received a basal diet, while group R2 received a diet consisting of 70%R1 and 30% PKM. Bird performance, AME, NE, and N balance were measured in a calorimetry system. The results showed that there was no interaction (P > 0.05) between the age of the birds (20 versus 40 days) and the dietary treatments (D1 and D2) for the AID and SID of most Aas, except for the values of aspartate (Asp) regarding AID and SID. The trends of age effect on AA digestibility were used and the effect of diets on AA digestibility was similar to the AID of AA values. Finally, results regarding the effective energy value and energy conversion efficiency of PKM revealed that age significantly affected AME, NE, and AME/GE of PKM (P < 0.05). Additionally, the conversion rates of NE and AME of PKM were 72.22% and 79.98% during the starter and finisher phases, respectively. In conclusion, the results indicate that age affects the NE of PKM and the supplementation of phytase did not improve the digestibility of PKM amino acids.