Effects of dietary supplementation of Escherichia coli 6-phytase levels on growth performance, nutrient digestibility, and blood inositol in weanling piglets.

Objective: : This study aimed to investigate the effect of different levels of phytase supplementation on growth performance parameters, nutrient digestibility, amino acid digestibility, and blood inositol concentration in weanling piglets that fed corn-soybean meal diet.

Methods: : Weanling piglets were allocated to one of the five feeding treatments: control, a corn-soybean meal diet; dietary supplementation of 500 FTU/kg phytase; dietary supplementation of 750 FTU/kg phytase; dietary supplementation of 1,000 FTU/kg phytase; dietary supplementation of 1,500 FTU/kg phytase. The experiment had two feeding phases (phase 1, d 1 to 21; phase 2, d 22 to 42) to clarify effects of dietary phytase supplementation.

Results: : The final body weight, average daily gain, and gain-to-feed ratio in the whole experimental period were increased linearly in response of elevated levels of dietary phytase supplementation (p < 0.01). There was no significant difference in average daily feed intake in the whole experimental period. In phase 1, there was a linear increase in apparent total tract digestibility of crude protein (CP), gross energy, and calcium as the level of dietary phytase supplementation increases. Phosphorus digestibility tended to be linearly increased (p = 0.056). In phase 2, linear increases were observed (p < 0.01) in calcium and phosphorus digestibility. Additionally, CP digestibility was linearly increased (p < 0.05). Dry matter digestibility showed a quadratic effect (p < 0.05). The digestibility of arginine, leucine, lysine, tryptophan, alanine, and phenylalanine and cysteine showed a linear increase (p < 0.01). There was a linear increase (p < 0.01) in blood myo-inositol levels in phase 2.

Conclusion: : Dietary phytase supplementation at levels greater than 1,000 FTU/kg significantly improved growth performance, nutrient digestibility, and blood myo-inositol concentrations in weanling pigs. However, further studies are necessary to investigate the effects of super dosing and to determine the optimal phytase dosage.