Determination of the standardized ileal digestible calcium requirement of male Arbor Acres Plus broilers from day 11 to 24 post-hatch

Requirement of digestible calcium at different dietary concentrations of digestible phosphorus for broiler chickens. 2. Broiler growers (d 11 to 24 post-hatch)

“…The SID Ca intake was negatively correlated with SID P intake (r = −0.24; P < 0.01) and SIDC of P (r = −0.49; P < 0.001). The negative influence of increasing dietary Ca on ileal P digestibility has been reported previously ( Mutucumarana et al 2014a ; Walk et al, 2021b , 2022 ). Similarly, a reduced P absorption with increasing dietary Ca has been reported in young turkeys using yttrium-91 as a reference substance ( Hurwitz et al, 1978 ).…”

“…The negative effect of increasing dietary Ca concentrations on Ca digestibility is attributed to excess Ca forming insoluble Ca-P complexes in the digestive tract ( Selle et al, 2009 ). Walk et al (2021b , 2022 ) also observed decreased standardized ileal Ca digestibility with increasing dietary SID Ca concentrations. In contrast, David et al (2021c) found no effect of increasing dietary SID Ca concentration (3.3–5.5 g/kg) on the SIDC of Ca in broiler starters.…”

“…The SID Ca requirements of 4.9 and 3.8 g/kg have been reported by Walk et al (2021b , 2022 ) for maximized P retention of broiler starters and growers, respectively. However, in the current study, the SID Ca requirement prediction for P retention was not made due to the linear Ca effect.…”

“…Similar findings were reported in broiler starters ( David et al, 2021c ) and in growing pigs ( González-Vega et al, 2016 ; Lagos et al, 2019 ). Recently, Walk et al (2022) reported a range of SID Ca of 3.94 to 5.15 g/kg to maximize the bone ash for broiler growers (11–24-day-old) using different nonlinear prediction models (quadratic polynomial model, straight-broken line, and quadratic-broken line regressions). The predicted estimates were higher than the current estimate (3.69 g/kg).…”

“…For instance, based on current findings, that the SID Ca requirement would be higher if the dietary P is higher. Finally, different strains of broilers were utilized in these studies; Arbor Acres plus by Walk et al (2021b , 2022 ) whereas Ross 308 in our studies. However, whether these contemporary strains use Ca with different efficiencies cannot be established with any clarity due to lack of published data.…”