A Preliminary Evaluation on Poly(3-Hydroxypropionic Acid) as a Novel Feed Additive on Growth Performance, Nutrient Digestibility, Selected Culturable Fecal Bacterial Counts, and In Vitro Fecal Fermentation in Growing Pigs.

Poly(3-hydroxypropionate) (P3HP) is a biodegradable member of the polyhydroxyalkanoate family that can be degraded into 3-hydroxypropionic acid, a three-carbon organic acid with potential biological activity. Although P3HP has attracted considerable interest for its microbial production and industrial applications, its potential as a feed ingredient in monogastric animals remains largely unexplored. Therefore, we aim to assess the effects of dietary P3HP supplementation on growth performance, nutrient digestibility, fecal N retention and apparent N absorption, selected culturable fecal bacterial counts, and in vitro fecal fermentation in growing pigs. A total of 100 [Duroc × (Landrace × Yorkshire) pigs; initial body weight 25.03 ± 1.70 kg] were assigned to four dietary treatments containing 0, 0.1, 0.2, and 0.3% P3HP for 6 weeks. At the end of the experimental period, dietary P3HP supplementation did not significantly (p > 0.05) affect final body weight, average daily gain, dry matter digestibility, nitrogen digestibility, apparent nitrogen absorption variables, or in vitro fecal fermentation in growing pigs but exhibited linear or quadratic trends (p < 0.1), with the most favorable numerical responses observed at the 0.2% inclusion level. In summary, although dietary P3HP supplementation did not significantly affect the principal measured outcomes, the favorable trends observed support further investigation of its potential as a novel feed additive for growing pigs.