Effects of Yucca schidigera Supplementation on In Vitro Cecal Fermentation and In Vivo Nutrient Digestibility in Male and Female Lean Fattening Pigs

The effect of Yucca schidigera extract (YSE; 10.8% saponins) on in vitro caecal disappearance (IVCD) was tested by incubating pre-digested feed with 0, 150, or 300 mg YSE/kg using caecal inocula from male and female pigs (Experiment 1). The apparent total tract digestibility (ATTD) of nutrients and fermentation products were assessed in vivo in 40 crossbred finishing pigs fed with 0 or 300 mg YSE/kg for 42 days (Experiment 2). In Experiment 1, YSE did not affect IVCD or gas production, but reduced caecal ammonia-N across sexes (p < 0.05). Caecal pH decreased progressively with increasing YSE in female-derived inocula only (p = 0.015), and volatile fatty acid (VFA) were suppressed in females at the highest dose (p = 0.013), while male-derived inocula remained unaffected. Entire males exhibited higher IVCD (p < 0.001) and lower ammonia-N (p = 0.034) and VFA production (p < 0.10) than females. In Experiment 2, YSE did not influence faecal ammonia-N, or VFA profile (p > 0.10), but reduced the ATTD of crude protein (p < 0.001) and organic matter (p < 0.001) relative to the control diet. YSE selectively modulated in vitro caecal fermentation in pigs, but these effects were not confirmed in vivo.