Interpretive Summary: A time-series effect of phytase supplementation on phosphorus utilization in growing and finishing pigs fed a low-phosphorus diet   

By: Dr. Emily Taylor

The current study's authors aimed to determine a time-series effect of phytase on phosphorus (P) utilization in growing and finishing pigs. Growth performance, apparent total tract digestibility (ATTD) of nutrients, P excretion, and plasma concentrations of minerals were evaluated during two experiments. Ninety-six growing pigs were arranged as a 3x4 factorial consisting of 3 corn-soybean meal-based diets including a P-adequate positive control (PC), a low-P negative control (NC; no inorganic P), and NC supplemented with phytase. 

Pigs fed the PC diet had higher BW, average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F) during the first experiment, with an interaction of time and diet on BW and ADG. In addition, there were linear and quadratic increases with ADFI and G:F over time, respectively. However, a quadratic increase in BW, ADG, and G:F overtime was seen during the second experiment. Similarly, experiments 1 and 2 eluded an improvement in growth performance with the addition of phytase except for ADFI in experiment 2. The addition of phytase improved the ATTD of both Ca and P during both experiments. There was an interaction between diet ad time on the total and water-soluble P (WSP), with WSP being reduced by 45%, 32%, and 35% over the growing, finishing, and entire grow-finish period. 

In conclusion, the authors agree that there are positive effects of phytase during the grow-finish stage of pigs; however, these effects will vary over time. Therefore, the authors suggest that time-sensitive applications of phytase be carried out with pigs depending on the aim of the producer or researcher.

This article is available in the Journal of Animal Science.