Comparison of mucosal phosphatase activity, phytate degradation, and nutrient digestibility in 3-week-old turkeys and broilers at different dietary levels of phosphorus and phytase

A comparison between 3-wk-old female turkeys (B.U.T. 6) and broilers (Ross 308) was per-formed to study the effects of species, dietary P, Ca, and phytase levels on gut mucosal phosphatase activity, myo-inositol hexakisphosphate (InsP6) degradation along the digestive tract, digestibility of P, Ca, and amino acids, and concentrations of myo-inositol in the digesta and blood. The experimental diets were corn-soybean meal-based and identical for both species. Two dietary P and Ca concentrations (CaP-: 4.1 g P/kg, 5.5 g Ca/kg and CaP+: 9.0 g P/kg, 12.0 g Ca/kg) and 2 levels of phytase supplementation (0 and 1,500 FTU/kg) were used in a 2 pound 2 factorial design and fed to the animals for 7 d in their third week of age. Each diet was ran-domly assigned to 6 broiler and 6 turkey pens, with 10 birds each. After slaughter, blood, digesta from the crop, gizzard, duodenum, lower ileum, and mucosa from the jejunum were collected. When fed CaP- without phy-tase supplementation, there were no differences between species in gut mucosal phosphatase activity, prececal InsP6 disappearance, and P and Ca digestibility, indicat-ing a similar intrinsic capacity for phytate degradation in both species. When fed CaP+ without phytase supple-mentation, turkeys showed higher prececal InsP6 disap-pearance than broilers. Phytase supplementation increased prececal InsP6 disappearance and digestibility of P and Ca in both species. However, the phytase-induced increase in prececal InsP6 disappearance was more pronounced in broilers than in turkeys, possibly due to more adequate conditions for phytase activity in the broiler crop. In broilers, phytase supplementation increased amino acid digestibility overall, whereas, in tur-keys, it increased with CaP+ and decreased with CaP-. In addition, the relationship between myo-inositol con-centration in the ileum and blood differed between spe-cies, indicating differences in myo-inositol metabolism. It was concluded that 3-week-old turkeys and broilers differ in nutrient digestibility and InsP degradation in some segments of the digestive tract but have similar endoge-nous when fed low P and Ca diets.

Automated summary

A comparison between 3-week-old female turkeys and broilers was conducted to investigate the impact of species, dietary P, Ca, and phytase levels on gut mucosal phosphatase activity, InsP6 degradation, nutrient digestibility, and myo-inositol concentrations. The results showed that both species have similar intrinsic capacity for phytate degradation when fed low P and Ca diets, but differ in InsP degradation and nutrient digestibility in certain segments of the digestive tract.