True phosphorus digestibility of black-eyed pea and peanut flour without or with phytase supplementation in broiler chickens

Abstract

Two studies were conducted to determine the true P digestibility (TPD) of black-eyed pea (BEP) and peanut flour (PNF) and the TPD response to phytase supplementation using the regression method. Sequential diets containing 115, 230, or 345 g of BEP/kg (experiment 1) and 115, 230, or 345 g of PNF/kg (experiment 2) without or with 1,000 units of phytase/kg were formulated. Chromic oxide was added to the diets at the rate of 5 g/kg as an indigestible marker. At 20 d posthatch in each study, 384 male broiler chickens (Ross 708) were weighed and allotted to the diets with 8 replicates of 8 birds each in a randomized complete block design. The birds had free access to the experimental diets until d 26 posthatch. In both studies, dietary P increase and phytase supplementation improved (P < 0.001) growth performance of the broiler chickens. There were linear increases (P < 0. 001) in ileal and excreta P output but a linear decrease (P < 0.001) in apparent P digestibility with an increase in dietary P levels. Phytase supplementation reduced (P < 0.001) ileal P and excreta P output and increased (P < 0.001) apparent P digestibility and retention. Apparent Ca digestibility was affected (P < 0.01) by P level and phytase addition in BEP and by P level (P < 0.05) in PNF. Apparent Ca retention in BEP increased (P < 0.05) with phytase addition. The TPD in the BEP increased (P < 0.01) from 29 without phytase to 83% with the addition of 1,000 units of phytase/kg. There was an increase (P < 0.01) in TPD of PNF from 67 without phytase to 75% with phytase supplementation. There was a corresponding increase (P < 0.01) in true P retention from 10% without phytase to 61% with phytase in birds on BEP diets and an equivalent increase (P < 0.01) in true P retention from 74% without phytase to 84% with phytase in birds that received the PNF diets.

Effects of dietary total phosphorus concentration and casein supplementation on the determination of true phosphorus digestibility for broiler chickens

“…Apparent precaecal digestibility and total tract retention of P. Furthermore, the precaecal digestibility of DM decreased with graded inclusion of SBM for birds fed the moderate-P diets, regardless of casein addition. This may be attributed to the replacement of highly digestible corn starch with assay feed ingredients, which has been reported in previous studies (Dilger and Adeola 2006;Iyayi et al 2013;Liu et al 2013). However, there were no linear or quadratic effects of SBM levels on the precaecal digestibility of DM for broilers fed the low-P diets, which is in agreement with the study of Liu et al (2014) using experimental diets at low levels of SBM.…”

“…In the present study, precaecal digested P was regressed against dietary P intakes for birds fed diets with or without casein supplementation at moderate or low total P concentrations using the following equation (Iyayi et al 2013):…”

Measurement of true ileal digestibility of phosphorus in some feed ingredients for broiler chickens

“…It is known that mathematical errors are inherent in any extrapolation beyond the data recorded (Moughan et al, 1998). Such negative estimates for endogenous P losses, with the regression method, have also been previously reported (Iyayi et al, 2013;Liu et al, 2013;Mutucumarana et al, 2014).…”

Effect of feeding graded levels of crude protein on nutrient utilization and feather growth in Lady Amherst's pheasants

“…Apparent retention of P ranged from 9.2% to 13.5%. Apparent retention of P in growing chicken ranged from 23% to 35% [Iyayi et al, ], whereas, apparent retention of P in pheasants ranged from 47.9% to 53.1% [Sultan et al, ]. Thus, it seems that utilization of P in birds is highly variable depending upon the nature of the diet, types of cereals, phytate content, processing of feed, and blending of different feed ingredients [Suttle, ].…”