Modifying broiler diets with phytase and vitamin D metabolite (25-OH D(3)): impact on phosphorus in litter, amended soils, and runoff

Effects of phytase and 25-hydroxyvitamin D3 supplementation on growth performance and bone development in weaned piglets in Ca- and P-deficient dietary

BACKGROUND

The beneficial function of phytase and 25-hydroxyvitamin D3 (HyD) on the feed utilization rate has been widely investigated. However, studies concerning its influence on weaned piglets largely lag behind. The aim of this study was to investigate the effects of phytase and HyD supplementation on the growth performance and bone development in weaned piglets under dietary Ca and P deficiency.

RESULTS

The results showed that dietary Ca and P deficiency decreased (P < 0.05) the content of serum P in 6-10 kg piglets, as well as reducing (P < 0.05) the contents of serum Ca and P, average daily gain (ADG), bone mineral density (BMD), breaking force (BF), bone ash and femur Ca in 10-20 kg piglets. Compared with the control group, the feed-to-gain ratio (F/G) of 6-10 kg piglets in the Phy group was decreased (P < 0.05), whereas the ADG, blood Ca and P, BMD, BF, bone ash, P apparent digestibility, Ca and P retention rate of 10-20 kg piglets were increased (P < 0.05). The contents of serum osteocalcin and HyD in 6-10 kg piglets and ADG were higher than in the control group (P < 0.05), as well as the contents of serum Ca and HyD in 10-20 kg piglets in the HyD treatment group. Supplementation with both Phy and HyD decreased the F/D (P < 0.05) and increased the contents of serum Ca, P and HyD in 6-10 kg piglets as well as enhancing the ADG, BMD, BF, bone ash, femur Ca and P, serum Ca and P, HyD, and the apparent digestibility and retention of Ca and P (P < 0.05) in 10-20 kg piglets. Supplementation with Phy and HyD in Ca- and P-deficient dietary decreased bone resorption, and improved tight arrangement of collagen fibers and oblique fibers in weaned piglets.

CONCLUSION

These data indicated that supplementation with both 1500 U kg^-1 Phy and 50 μg kg^-1 HyD could enhance dietary Ca and P utilization and promote bone development in low Ca and P dietary, and supplementation with both Phy and HyD had a significant synergy effect compared to single supplement. © 2021 Society of Chemical Industry.

Assessing changes in the composition of broiler litters from commercial poultry units in Northern Ireland following the adoption of phytase in diets

Microbial phytases increase the bioavailability of phytate P in poultry diets, and a survey was undertaken to determine if their use had lowered the P composition of broiler litter in Northern Ireland compared with standard values of litter composition listed in the current United Kingdom fertilizer recommendations. Litter samples were collected from a total of 20 units across Northern Ireland in 2010 and analyzed for DM, N, phosphate (P2O5), potash (K2O), magnesium oxide (MgO), water-soluble P (WSP), ammonium N (NH4N), and uric acid N. Dry matter of litter was positively correlated (P < 0.001) with N (r(2) = 0.65), P2O5 (r(2) = 0.63), K2O (r(2) = 0.56), and MgO (r(2) = 0.58). Negative correlations were observed between litter DM and WSP (r(2) = 0.45, P < 0.001) and NH4N (r(2) = 0.22, P = 0.038) contents. A standardized litter composition with a 60% DM gave a phosphate content of 13.7 kg/t that was 45% lower than the fertilizer book value (RB209), but there were only slight differences (<3%) between book values and DM standardized values for N and potash contents. Uric acid and NH4 contents were similar to published values. Mean N:P ratio (by weight) of litter increased from 3.7 in 2004 to 5.0 in 2010, lowering the risk of oversupply of P if land applications are targeted to meet N supply. Using the standard RB209 values to plan land applications of broiler litter to meet crop P demands risks undersupplying P, and there is a need for the regulatory values to be modified in light of the changing composition of broiler litter.