Dietary Calcium and Non-phytin Phosphorus Interaction on Growth, Bone Mineralization and Mineral Retention in Broiler Starter Chicks

Abstract

An experiment was conducted to study the requirement of calcium (Ca) and non-phytin phosphorus (NPP) in commercial broilers during starter phase. Seven hundred and twenty day-old Vencob male broiler chicks were randomly distributed into 144 stainless steel battery brooders, 5 birds in each. Four levels each of Ca (6, 7, 8, and 9 g/kg) and NPP (3, 3.5, 4, and 4.5 g/kg diet) were fed in a factorial design in a corn-soya basal diet. Levels of dicalcium phosphate and oyster shell grit were adjusted to obtain the desired levels of Ca and NPP. Each diet was fed ad libidum to chicks in 9 battery brooders from one d to 21 d of age. Body weight gain and feed intake were depressed (p<0.01) by increasing the dietary Ca level (8 and 9 g/kg) at lower levels of NPP (3 and 3.5 g/kg diet). The growth depression observed at lower NPP level was alleviated by reducing the Ca content to 6 g/kg diet. The tibia ash content and tibia breaking strength increased with increase in both Ca (>6 g/kg) and NPP (>3 g/kg) levels. The leg abnormality score decreased (p<0.01) with increase in NPP content in the diet at all levels of Ca tested. The serum Ca and inorganic P levels were increased with increase in the level of the respective mineral in the diet, but the serum concentration of Ca and P were inversely related to the level of NPP and Ca, respectively /kg diet. In general, the excretion of macro minerals (Ca, and P), and micro minerals {zinc (Zn), manganese (Mn), iron (Fe), and copper (Cu)} was significantly lower at lower levels of Ca and NPP tested (6 and 3 g/kg diet, respectively). The mineral excretion increased with increase in dietary Ca and NPP levels, more conspicuously at the disproportionate ratio of these minerals (>2:1, Ca and NPP). Similarly, the retention of Zn, Mn, and Fe in liver was significantly higher (p<0.01) at lower levels of Ca and NPP tested. Results from this study indicate that the commercial broilers do not require more than 3 g NPP and 6g Ca/kg diet during starter phase (up to 21 d of age) for optimum weight gain, feed efficiency and utilization of Ca, P, Zn, Mn, Fe and Cu. However, the requirements of these minerals for optimum bone mineralization were higher than the levels suggested above.

Dietary calcium or phosphorus deficiency impairs the bone development by regulating related calcium or phosphorus metabolic utilization parameters of broilers

“…(2017) , who found that broilers fed with 0.23% NPP diet had lower tibia BMD, BBS, and ash content than the control broilers. Rama Rao et al. (2003) also found that a decrease of Ca and NPP levels in the broiler diet had a negative effect on tibia BBS and ash content.…”

“…Many studies demonstrated that the bone development parameters, such as tibia BMD, BBS, and ash content of broilers, were susceptible to dietary Ca or P level ( Williams et al., 2000a , Rama Rao et al., 2003 , Liu et al., 2017 ). Results from the present study showed that the Ca- or P-deficient diets negatively affected the tibia BMD, BBS, and ash content of broilers.…”

Dietary phosphorus deficiency impaired growth, intestinal digestion and absorption function of meat ducks

“…Hulan et al [25] found that the dietary Ca:nPP above 2.81:1 could depress the growth performance and FI in broilers. And Rama Rao et al [26] also observed that broilers fed diets with 2.3–3:1 Ca:nPP had poor performance. Because the two minerals tend to form calcium phosphate, an insoluble complex in the chicken gut resulting in reduced absorption, which may be the reason for growth retardation at higher Ca:nPP [27].…”

The effect of dietary phosphorus on bone development in dairy heifers

“…Feeding heifers 0.39% P also increased (P < 0.01) bone Cu content compared with feeding heifers 0.29% P. Bovine bone contains approximately 10 μg of copper per g (Doyle, 1979) on an ash basis and copper plays an important role in collagen maturation linked to its function as a cofactor in lysyl oxidase (Turnlund, 2006). Increasing dietary P from nonphytin sources can adversely affect Cu bioavailability by increasing Cu excretion (Rama Rao et al, 2003), but that does not explain lower bone Cu content observed in this study when heifers were fed diets containing 0.29% P compared with feeding heifers 0.39% P. Prince et al (1984) reported increased levels of liver Cu when pigs were fed high levels of dietary P (>1.00) but could not discount potential Cu contamination in P supplements used to alter dietary P. Likewise, in this study the need for intensive measurement of dietary Cu was not foreseen and thus not undertaken; therefore, dietary influences in regard to differences in bone Cu content observed in this study cannot be dismissed.…”