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It has been proven that the use of phytase in the diets of pigs improves growth performance, nutrient utilization, and bone mineralization of pigs at different physiological stages while reducing the amount of phosphorus (P) lost into the environment. The aim of this study was to investigate a time-series effect of phytase supplementation on P utilization in growing and finishing pigs fed a low-P diet. Two trials were carried out where 96 growing pigs were allocated to 3 diets with 8 replicate pens (4 pigs/pen). Diets were composed of 3 corn–soybean meal-based diets including a P-adequate positive control, a low-P negative control, and negative control supplemented with phytase at 1,000 FYT/kg. Growth performance, apparent total tract digestibility of nutrients, excretion, and plasma concentrations of minerals were evaluated. The sampling time points were days 7, 14, 21, and 28 in trial 1, and days 14, 26, 42, and 55 in trial 2.
In trial 1, pigs fed the positive control had higher body weight, average daily gain, average daily feed intake, and gain-to-feed ratio when compared with pigs fed the negative control. There was an interaction between time and diet on the body weight and average daily gain of pigs while a linear and quadratic increase was observed with the average daily feed intake and gain-to-feed ratio, respectively, over time. Phytase supplementation improved all growth performance responses. Pigs fed the positive control had greater apparent total tract digestibility of P and Ca than pigs fed the negative control. There was no interaction effect on the apparent total tract digestibility of nutrients. Phytase addition improved the apparent total tract digestibility of P and Ca over pigs fed the negative control. There was an interaction between diet and time on the total and water-soluble P excreted. There was a quadratic decrease in plasma concentration of Ca in pigs over time. In trial 2, there was a quadratic increase in body weight, average daily gain, and gain-to-feed ratio of pigs over time. Similarly, the inclusion of phytase improved all growth performance parameters except average daily feed intake. A linear increase in the apparent total tract digestibility of dry matter, P, and Ca occurred over time. Phytase inclusion improved the apparent total tract digestibility of P and Ca. Plasma concentrations of P were improved by phytase addition. Phytase supplementation of the negative control reduced water-soluble P excretion by 45%, 32%, and 35% over the growing, finishing, and entire grow-finish period, respectively.
In conclusion, phytase improves the utilization of P in growing and finishing pigs; however, the magnitude of the effect on responses may vary over time.
Babatunde OO, Adeola O. A time-series effect of phytase supplementation on phosphorus utilization in growing and finishing pigs fed a low-phosphorus diet. Journal of Animal Science. 2022; 100(1): skab350. https://doi.org/10.1093%2Fjas%2Fskab350