Effects and interaction of dietary calcium and nonphytate phosphorus for slow-growing yellow-feathered broilers between 56 and 84 d of age

Abstract

This experiment investigated the effect and interaction of dietary calcium ( Ca ) and nonphytate phosphorus ( NPP ) on growth performance, tibial characteristics, carcass traits, and meat quality for slow-growing yellow-feathered broilers during 56 to 84 d of age. A 3 × 3 factorial arrangement was used, and 720 56-day-old broilers were randomly divided into 9 groups and fed with diets containing different levels of Ca (0.70, 0.80, 0.90%) and NPP (0.30, 0.35, 0.40%) for 28 d. The dietary Ca level affected the ADFI of yellow-feathered broilers ( P < 0.05), and the ADFI of birds fed with 0.90% Ca was increased ( P < 0.05) compared with that of birds fed with 0.70% Ca. Birds received 0.35 or 0.40% NPP had higher final BW, ADG, and ADFI than those fed with 0.30% NPP ( P < 0.05). The tibial diameter of birds fed with 0.80% Ca was increased compared with that of other groups ( P < 0.05). The dietary NPP level did not affect tibial characteristics ( P > 0.05). The dietary Ca level did not affect carcass traits ( P > 0.05). When broilers were fed with 0.30% P, the semieviscerated percentage was increased compared with birds fed with 0.40% NPP ( P < 0.05). The dietary Ca level had significant effects on the L∗ value and shear force of the breast muscle, and the dietary NPP level affected the L∗ value and drip loss of the breast muscle ( P < 0.05). Furthermore, the effect of interaction between the level of Ca and NPP was observed on the L∗ and a∗ value ( P < 0.05). In conclusion, dietary Ca had influence on performance, tibial characteristics, and meat quality of yellow-feathered broilers, and dietary NPP affected performance, tibial characteristics, and carcass traits. Furthermore, the effect of interaction between the dietary Ca and NPP level was observed on carcass traits and meat quality. Considering all aforementioned indicators, 0.80% Ca and 0.35% NPP were recommended for slow-growing yellow-feathered broilers aged 57 to 84 d of age.

Recommended levels of calcium and non-phytate phosphorus for yellow-feathered broilers (finisher phase)

“…As the most abundant minerals in the body, provision of appropriate amounts of dietary Ca and P is critical for poultry production. In addition to their accretion in bone, they are essential for biological processes such as intracellular signaling, and muscle contractions [ 1 , 10 ]. Excessive dietary Ca and P, however, have a harmful impact on growth of broilers [ 6 , 12 , 13 ].…”

“…Also, our previous study on broilers aged 56 to 84 d also showed that dietary Ca level significantly affected shear force and dietary NPP level affected drip loss of breast muscle. The change of meat quality in the current research might be related to oxidative stress because poor meat quality of broilers is commonly seen along with oxidative damage, and NPP could reduce lipid and protein oxidation [ 10 ]. Under the present experimental conditions, for yellow-feathered broilers at finisher phase, dietary level of 0.75% Ca and 0.25% NPP achieved the best meat quality.…”

“…At the beginning (d 85) and end (d 105) of the experiment, Birds were weighed. The indicators of growth performance were measured as previously described [ 10 ].…”

“…At the end of the experiment (d 105), in each replicate, two birds (close to average final body weight [FW]) were chosen and deprived of feed overnight before slaughter. Breast muscles (the pectoralis major ) were collected, and the drip loss and shear force were determined with the method of Wang et al [ 10 ].…”

“…At the beginning (d 85) and end (d 105) of the experiment, Birds were weighed. The indicators of growth performance were measured as previously described [10]. At the end of the experiment (d 105), in each replicate, two birds (close to average final body weight [FW]) were chosen and deprived of feed overnight before slaughter.…”