Determination of the standardized ileal digestible calcium requirement of male Arbor Acres Plus broilers from day 25 to 42 post-hatch

Requirement of digestible calcium at different dietary concentrations of digestible phosphorus for broiler chickens 3. Broiler finishers (d 25 to 35 post-hatch)

“…However, at 4.5 g/kg SID P, the SIDC of Ca was reduced at higher SID Ca (3.5 and 4.0 g/kg) concentrations and this may be attributed to the formation of insoluble Ca-P complexes in the digestive tract due to excess Ca ( Selle et al., 2009 ). A similar effect of excess Ca has been reported in our previous ( David et al., 2022 ) and other ( Walk et al., 2021 ; 2022a , b ) studies. For the SIDC of Ca, although the linear SID P effect was not significant in the full model, it was included in the reduced model ( Figure 2 a) as the interaction between SID Ca and SID P was significant.…”

“…Based on overall findings, a combination of 3.5 g/kg SID P and 3.0 to 3.5 g/kg SID Ca may be recommended for the optimum tibia ash. This estimate is comparable to the recent findings of Walk et al. (2022b) who proposed a SID Ca concentration of 3.7 g/kg for the maximum tibia ash in 25 to 42-day-old Arbor Acres plus broilers.…”

“…The negative influence of increasing dietary Ca on ileal P digestibility has been reported previously ( Mutucumarana et al. 2014a ; Walk et al., 2021 ; 2022a , b ). Based on the RSM, the concentration of SID Ca that minimized SIDC of P and SID P intake were 3.88 and 3.98 g/kg, respectively, regardless of SID P concentrations in the current study, further confirming the negative effect of high SID Ca (above 3.5 g/kg) on the absorption of dietary P.…”

“… Walk et al. (2021 ; 2022a , b ) recommended SID Ca requirements for the maximum bone ash in 0 to 10, 11 to 24 and 25 to 42-dayold broilers as 5.30, 5.15, and 3.70 g/kg, respectively. Corresponding values in our studies ( David et al., 2021c ; 2022 ; current work) were lower in 1 to 10, 11 to 24, and 25 to 35-day-old broilers at 4.51, 3.69, and 3.00 to 3.50 g/kg, respectively.…”

Determination of the standardized ileal digestible calcium requirement of Ross broilers from hatch to day 14 post-hatch

“…There is a single maximum, not a plateau, and anything below or above the maximum is considered lower predicted performance or nutrient utilization levels ( Pesti et al., 2009 ). In this regard, the QP model may be useful to estimate deficiencies or toxicities, but generally results in a greater estimated requirement compared with the SBL or QBL ( Pesti et al., 2009 ; Walk et al., 2022 ). When using the QP, it may be possible to estimate the requirement at a value other than the maximum, such as 90% to 99% of the maximum ( Pesti et al., 2009 ), to account for the higher estimated requirements compared with other non-linear models.…”