In 2 broiler trials, the effects of chestnut tannins on performance and meat quality (trial 1), and digestion (trial 2) were evaluated. In both trials, Ross 308 broilers received one of 2 basal diets: one basal diet contained corn and soy as main feed ingredients, while the challenge basal diet contained wheat, palm oil, and rapeseed meal. The composition of the basal diets was chosen to assess the interaction between chestnut tannins and diet composition. To both basal diets, chestnut tannins were added at 3 doses: 0 mg/kg (T−), 500 mg/kg (T+), or 2,000 mg/kg (T++), resulting in a total of 6 treatments. In trial 1, both basal diets containing 2,000 mg/kg chestnut tannins lowered broiler performance in grower and finisher phases. A tannin dose of 500 mg/kg had no effect on performance in either basal diet. Corn-based diets resulted in lower meat pH compared to wheat diets. Further, addition of chestnut tannins resulted in increased meat pH, and caused proportionally a lower meat drip loss and shear force for both basal diets. During the digestibility study (trial 2), blood was also collected. None of the treatments affected digestibility or blood parameters (glucose, non-esterified fatty acids, and triacylglycerols). Malondialdehyde (MDA) was measured in plasma to assess antioxidative properties of chestnut tannins. In wheat diets, chestnut tannins significantly lowered plasma MDA demonstrating its antioxidative nature. Regarding gut health, crypt depth decreased proportionally with the dosage of chestnut tannins in both basal diets with significantly shallower crypts for the wheat diets compared to the corn diets. Relative intestinal growth was stimulated in the wheat diets proportionally to the tannin dose based on the larger relative gut length. In conclusion, chestnut tannins did not influence digestive metabolism, yet they lowered performance at higher doses regardless of feed ingredients used in the diet. Tannins positively affected meat quality and when added to wheat diets, intestinal growth was stimulated and the antioxidative status of the broilers improved.

The present study evaluated gluco-conjugation as a measure to delay thymol absorption and enhance its antimicrobial activity in the gut of weaned piglets. The three dietary treatments consisted of a basal diet without additives (T_CON), supplemented with thymol at 3.7 mmol/kg dry matter (T_THY), or with an equimolar amount of thymol α-D-glucopyranoside (T_TαG). Each dietary treatment was replicated in 6 pens with 2 piglets per pen (n = 12 for analytical parameters) and was supplemented for 14 days. The total (free plus gluco-conjugated) thymol concentrations in the stomach contents were 14% lower in T_TαG as compared to T_THY piglets. Neither of the additives could be detected further down the gut. E.coli counts in the proximal small intestine were significantly lower in T_THY than in T_TαG pigs (3.35 vs. 4.29 log₁₀ CFU/g); however, other bacterial counts and their metabolites were unaffected by treatment. A metagenomic bacterial analysis revealed a great relative abundance of Lactobacillus spp. in the distal small intestine (range 88.4–99.9%), irrespective of treatment. The intestinal barrier function was improved by T_THY, but not T_TαG, compared to T_CON. In conclusion, gluco-conjugation did not result in higher thymol concentrations in the gut, but conversely, it seemed to diminish the biological effects of thymol in vivo.

Farmers face difficulties in redeeming their investment in larger litter sizes since this comes with larger litter heterogenicity, lower litter resilience and risk of higher mortality. Dietary oligosaccharides, given to the sow, proved beneficial for the offspring’s performance. However, giving oligosaccharides to the suckling piglet is poorly explored. Therefore, this field trial studied the effect of dietary short-chain fructo-oligosaccharides (scFOS; 1g/day; drenched) supplementation to low (LBW, lower quartile), normal (NBW, two intermediate quartiles) and high (HBW, upper quartile) birth weight piglets from birth until 7 or 21 days of age. Performance parameters, gut microbiome and short-chain fatty acids profile of feces and digesta were assessed at birth (d 0), d 7, weaning (d 21.5) and 2 weeks post-weaning (d 36.5). Additional parameters reflecting gut health (intestinal integrity and morphology, mucosal immune system) were analysed at d 36.5. Most parameters changed with age or differed with the piglet’s birth weight. Drenching with scFOS increased body weight by 1 kg in NBW suckling piglets and reduced the post-weaning mortality rate by a 100%. No clear difference in the IgG level, the microbiota composition and fermentative activity between the treatment groups was observed. Additionnally, intestinal integrity, determined by measuring intestinal permeability and regenerative capacity, was similar between the treatment groups. Also, intestinal architecture (villus lenght, crypt depth) was not affected by scFOS supplementation. The density of intra-epithelial lymphocytes and the expression profiles (real-time qPCR) for immune system-related genes (IL-10, IL-1ß, IL-6, TNFα and IFNγ) were used to assess mucosal immunity. Only IFNγ expression, was upregulated in piglets that received scFOS for 7 days. The improved body weight and the reduced post-weaning mortality seen in piglets supplemented with scFOS support the view that scFOS positively impact piglet’s health and resilience. However, the modes of action for these effects are not yet fully elucidated and its potential to improve other performance parameters needs further investigation.

Quercetin has been shown to alleviate mucosal damage and modulate the glutathione (GSH) redox system in the colon of rodents. In the current study, we assessed whether quercetin was able to mitigate small intestinal dysfunction in weaned pigs. Here, 224 weaned piglets were fed a diet containing quercetin at either 0, 100, 300, or 900 mg/kg diet until d14 post-weaning, followed by a common basal diet until d42. Eight animals per treatment were sampled at d5 and d14 post-weaning. In these animals, the small intestinal histomorphology, barrier function, and protein abundance of occludin, caspase-3, and proliferating cell nuclear antigen were assessed. None of these parameters were affected, and neither did quercetin improve performance up to d42 post-weaning. The GSH redox system was evaluated in blood, small intestinal mucosa, and liver. Quercetin did not affect the glutathione peroxidase, glutathione reductase, and glutamate–cysteine ligase activity in these tissues. In contrast, the hepatic glutathione transferase (GST) activity was significantly increased by quercetin supplementation at d5 post-weaning of 100, 300, and 900 mg/kg. Importantly, d5 was characterized by a more oxidized GSH redox status. To conclude, dietary quercetin had little effect on the small intestine, but did upregulate hepatic GST in the occurrence of redox disturbance.

The monoterpene thymol has been proposed as a valuable alternative to in-feed antibiotics in animal production. However, the effectiveness of the antimicrobial is comprised by its fast absorption in the upper gastrointestinal tract. In this work, two glucoconjugates, thymol α-d-glucopyranoside (TαG) and thymol β-d-glucopyranoside (TβG), were compared with free thymol for their potential to deliver higher concentrations of the active compound to the distal small intestine of supplemented piglets. Additionally, an analytical method was developed and validated for the simultaneous quantification of thymol and its glucoconjugates in different matrices. In stomach contents of pigs fed with 3333 μmol kg^–1 thymol, TαG, or TβG, total thymol concentrations amounted to 3048, 2357, and 1820 μmol kg^–1 dry matter, respectively. In glucoconjugate-fed pigs, over 30% of this concentration was present in the unconjugated form, suggesting partial hydrolysis in the stomach. No quantifiable levels of thymol or glucoconjugates were detected in the small intestine or cecum for any treatment, indicating that conjugation with one glucose unit did not sufficiently protect thymol from early absorption.