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

“…As also observed in the broiler starter ( David et al., 2021c ) and grower ( David et al., 2022 ) studies, the calculated SID Ca and SID P concentrations of most dietary treatments, in general, were comparable to the determined SID concentrations, providing confidence in the published values for the SID Ca and SID P of ingredients.…”

“…Based on published values of digestible Ca and P in feed ingredients ( Tables 1 and 2 ), equivalent SID Ca and SID P values were 4.25 and 3.91 g/kg, respectively. Most of the selected SID Ca (2.0–4.0 g/kg) and SID P (2.5–4.5 g/kg) concentrations of the diets used in this study were below the predicted target values based on previous findings for starters ( David et al., 2021c ) and growers ( David et al., 2022 ) which suggested the true requirements were lower than the targets. The ingredient and calculated nutrient composition of broiler starter crumbles (4.4 g/kg SID Ca; 5.0 g/kg SID P) and grower pelleted diet (3.69 g/kg SID Ca; 3.5 g/kg SID P) offered to broilers from d 1 to 10 and d 11 to 24, respectively, are shown in Table 3 .…”

“…A summary of the estimated requirements of SID Ca, SID P, and their ratio for growth performance and tibia ash in broiler starters ( David et al., 2021c ), growers ( David et al., 2022 ), and finishers (current study) is presented in Table 13 . It could be seen that the estimated requirements of SID P (5.0, 3.5, and 3.5 g/kg for starters, growers, and finishers, respectively) to maximize weight gain and tibia ash was similar within each growth phase.…”

“…In general, the analyzed concentration of proximate components, phytate, Ca and P of corn, soybean meal, limestone, dicalcium phosphate, and monosodium phosphate were within the range reported in the literature ( NRC, 1994 , 2012 ; Browning and Cowieson, 2014 ; Mutucumarana et al., 2014b , c ; 2015b ). It must be pointed out that the same batches of limestone and dicalcium phosphate used in the broiler starter ( David et al., 2021c ) and grower ( David et al., 2022 ) requirement studies were utilized in the current experiment. In addition, the same batches of corn and soybean meal used in the broiler grower study were used in the current study.…”

“…Recent interest in shifting feed formulations to digestible Ca ( Anwar et al., 2015 ; 2016a , b , c ; 2017 ; 2018 ; David et al., 2019 ; 2020 ; 2021a , b , c ) and digestible P ( Mutucumarana et al., 2014b , c ; 2015a , b ; Mutucumarana and Ravindran, 2016 ) has provided impetus for studies to estimate the requirements of digestible Ca and digestible P for broilers. Two studies have been conducted recently in our laboratory to determine the standardized ileal digestible ( SID ) Ca and SID P requirements for broiler starters (d 1–10 post-hatch; David et al., 2021c ) and broiler growers (d 11–24 post-hatch; David et al., 2022 ) for growth, bone mineralization, and mineral utilization. The present study, third in this series, focuses on the requirements of SID Ca and SID P for the maximization of growth performance, bone mineralization, and Ca and P retention in broiler finishers during d 25 to 35 post-hatch.…”