Context: Yucca schidigera extract, rich in saponins and bioactive compounds, gained attention as a phytogenic feed additive for its antimicrobial, antioxidant, and welfare-enhancing effects. Its supplementation has also been linked to lower gas emissions, improved gut health, and potential benefits for meat quality. However, its impact on nitrogen metabolism, carcase traits, and possible sex-specific responses in pigs, especially lean genetic types derived from Pietrain, remains underexplored. Aims: This study evaluated the effects of diet supplementation with Yucca schidigera extract on performances, welfare, carcase and meat quality in lean finishing pigs slaughtered at 115 kg average body weight, considering potential sex-related differences. Methods: Forty Pietrain crossbred lean pigs were used in a 42-day trial. Animals were homogeneously divided by sex into two experimental groups receiving either a commercial basal diet as control or the same diet supplemented with 300 mg/kg of yucca extract (two pigs per pen, five replicates per diet and sex). The variables measured were growth and feed performance, blood protein and catabolite profiles, behavioural patterns and carcase and meat quality. Key results: Yucca supplementation had no significant effect on growth performance or nitrogen mass balance, although females tended to grow more slowly than males. Serum urea levels remained stable in the yucca-supplemented group, while they increased in the control group. Females showed higher albumin, creatinine and cupric reducing antioxidant capacity levels than males. Behavioural patterns were not influenced by diet or sex. Carcase and meat quality were unaffected by yucca extract, although males produced brighter meat with lower protein content. Conclusions: Dietary supplementation with Yucca schidigera extract during the fattening phase did not compromise performance, animal welfare or meat quality. However, sex differences in blood protein catabolite profiles and meat quality were evident, possibly reflecting variations in protein metabolism and muscle development. Implications: Yucca schidigera extract at 300 mg/kg can be safely included in pig diets with no negative effects on growth, behaviour, nitrogen balance, or carcase and meat quality in lean finishing pigs, independent from sex. Also, variations in the blood protein composition across entire males and females suggest hormonal differences to be evaluated in further studies.

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.

Young dairy ruminants often have limited rumen fermentative capacity, which can impair adaptation to solid diet during weaning. This study evaluated the effects of ruminant colostrum supplementation to enhance in vitro rumen fermentation at weaning. A batch culture system using rumen inoculum from artificially reared lambs was incubated with ovine, bovine, or reconstituted bovine colostrum at 4 and 20 mL/L. Sequential colostrum fractionation was used to identify the main functional components. Whole colostrum supplementation at high doses reduced ruminal pH (p < 0.001) and increased gas production (+18%), ammonia-N (+41%) and butyrate proportion (+10%) across colostrum sources, indicating enhanced microbial fermentation. Responses were dose-dependent and consistent across colostrum sources. Lipid removal had minimal effects, whereas depletion of high-molecular-weight molecules, mostly IgG, markedly reduced gas production and protein degradation. Removal of medium-size proteins such as lactoferrin produced minor changes. Residual activity in low-molecular-weight fractions was retained likely associated with the presence of fermentable substrates and bioactive compounds. These findings indicate that colostrum may exhibit both nutritional and modulatory effects on in vitro rumen fermentation, with IgG identified as a key component. These findings support the preservation of IgG in colostrum-derived products to enhance rumen fermentation, although further in vivo validation is required to evaluate the effects in weaned ruminants.