Standardized total tract digestibility of phosphorus in copra expellers, palm kernel expellers, and cassava root fed...

An experiment was conducted to determine the apparent total tract digestibility (ATTD) and standardized total tract digestibility (STTD) of phosphorus (P) in copra expellers (CE), palm kernel expellers (PKE), and cassava root (CR). Eight barrows (initial BW of 40.0 kg, SD = 4.5) were individually housed in metabolism crates. A replicated 4×3 incomplete Latin square design was employed involving 4 dietary treatments, 3 periods, and 8 animals. Three experimental diets contained 40% CE, PKE or CR as the only source of P. A P-free diet mainly based on corn starch, sucrose, and gelatin was also prepared to estimate the basal endogenous loss of P. The marker-to-marker method was used for fecal collection. Values for the ATTD of P in the CE and PKE were greater than in the CR (46.0 and 39.7 vs -14.0%; p<0.05). However, the STTD of P did not differ greatly among the test ingredients (56.5, 49.0, and 43.2% in the CE, PKE, and CR, respectively). In conclusion, the ATTD of P values in CE and PKE were greater than that in CR, but the STTD of P did not differ greatly among CE, PKE, and CR.