Abstract
The bone abnormalities pose great concern in heavy, rapidly growing broilers, resulting in significant economic loss, and health issues in birds. To address these problems and prevent unnecessary mineral excretion into environment, it is crucial to optimise the inclusion level of dietary calcium in broiler’s diet. The calcium utilisation by the bird is also affected by its source, particle size, bioavailability etc. Hence this study aimed to study the effect of partially replacing conventional dietary calcium source with coated calcium on growth performance, immune response, carcass traits, blood calcium and phosphorus, and mineral retention in broilers. About 416 broilers were randomly distributed into four treatments, each with eight replicates of 13 birds and fed with iso-calcium, isocaloric, and isonitrogenous diet for 6 weeks. The T0 (control) was a basal diet while the T1, T2, and T3, were treatment diets in which conventional calcium source (limestone) was partially replaced with coated calcium by 10, 20, and 30% respectively. The growth performance, immunity, carcass traits, tibial morphometry, calcium and phosphorus content in serum, bone and excreta were studied. The birds of T3 group showed significantly higher body weight gain, feed conversion ratio, carcass yields compared to T0, T1, and T2 diet fed birds. Further the treatment groups exhibited significantly (P<0.001) higher cell-mediated and humoral immune responses and immune organ weights compared to control. The tibial bone weight, length and average diameter was highest in T3. Moreover, the T3 diet fed group also showed higher calcium and phosphorus content in serum and bone and lowest content of these minerals in the excreta compared to T2, T1 and control. Therefore, the dietary replacement of 30% conventional calcium source with coated calcium enhanced the growth performance, immunity, carcass traits and mineral retention in broilers.