Evaluation of calcium and non-phytate phosphorus deficient diets: effects on growth performance, carcase yield, tibia characteristics and jejunum histomorphology at 42 days of age in broilers.

1. The objective of this study was to ascertain the impact of dietary calcium (Ca) and non-phytate phosphorus (nPP) levels that were progressively reduced in feed on performance, carcase, tibia traits and jejunum crypt depth and villus height in broilers.2. For the purposes of this study, 480, one-day-old chicks were randomly distributed into four treatment groups, with eight replicates per group and 15 birds per replicate. The starter period consisted of two different diets; the control diet contained 0.96% Ca and 0.48% non-phytase phosphorus (nPP) and the L-nPP diet contained 0.90% Ca and 0.45% nPP. The grower and finisher periods consisted of four different diets, namely control, L-nPP1, L-nPP2 and L-nPP3. The Ca contents of the control, L-nPP1, L-nPP2 and L-nPP3 diets during the grower period were 0.87%, 0.83%, 0.79%, 0.75% and the nPP contents were 0.44%, 0.42%, 0.40%, 0.38%, respectively. In the finisher period, the Ca contents of the control, L-nPP1, L-nPP2 and L-nPP3 diets were 0.78%, 0.71%, 0.60%, 0.50% and the nPP contents were 0.39%, 0.35%, 0.30%, 0.30%, respectively.3. Dietary treatments had no effect on body weight or body weight gain; however, a decrease was observed in the L-nPP2 and L-nPP3 diet groups compared to the control group over the 11-24 d period.4. No significant differences were observed in terms of tibial diameter, wall thickness or cross-sectional area. However, tibial ash and shear force were significantly lower in all groups with reduced Ca and nPP levels compared to the control group. The group fed the L-nPP3 diet exhibited a significantly higher crypt depth in comparison to the control and L-nPP1 groups, which was accompanied by a lower ratio of villus height to crypt depth.5. Wheat and maize-based broiler diets can be fed with 23% reduced Ca and nPP levels of recommended values without adversely affecting growth performance but may compromise skeletal health and intestinal histomorphology of broilers.