This review examines the challenges faced by the pig industry, with a specific focus on improving the health and growth of weaned pigs. It emphasizes the immediate necessity of investigating alternative approaches to managing pig nutrition and health due to restrictions on the use of antibiotics and the prohibition of zinc oxide in weaned pig diets. The weaning phase is identified as a critical stage in piglet development, characterized by stressors that affect their gastrointestinal health, immune responses, and overall physiology. The primary challenge during weaning arises from transitioning piglets from a digestible milk-based diet to a less digestible cereal-based feed, causing nutritional stress. This manifests as reduced feed intake, leading to gastrointestinal disturbances, intestinal inflammation, and adverse effects on intestinal structure and microbiota. To address these challenges and optimize piglet development, various nutritional strategies have been explored. Notably, glucans, particularly β-glucans from fungi, cereals, algae, and yeast, show promise in alleviating weaning-related issues. Furthermore, it is important to highlight the critical roles played by Vitamin D and selenium in piglet nutrition. These essential nutrients can be sourced naturally from enriched mushrooms that are specifically enriched with Vitamin D and selenium, providing a sustainable dietary option. In conclusion, effective nutritional strategies, including glucans, Vitamin D, selenium, and enriched mushrooms, are beneficial for addressing weaning-related challenges.

The objective of this study was to compare the molecular, physiological and microbial effects of mushroom powder (MP), vitamin D₂ enriched mushroom powder (MPD₂) and zinc oxide (ZnO) in pigs post-weaning. Pigs (four pigs/pen; 12 pens/treatment) were assigned to: (1) basal diet (control), (2) basal diet + ZnO, (3) basal diet + MP (2 g/kg feed) and (4) basal diet + MPD₂ (2 g/kg feed). Zinc oxide supplementation improved the feed intake (p < 0.001); increased the caecal abundance of Lactobacillus (p < 0.05); increased the villus height (p < 0.05) in the duodenum, jejunum and ileum; increased the expression of chemokine interleukin 8 (CXCL8; p < 0.05); and decreased the expression of pro-inflammatory cytokine gene interleukin 6 (IL6; p < 0.05), tumour necrosis factor (TNF; p < 0.05), nutrient transporters peptide transporter 1 (SLC15A1; p < 0.05) and fatty acid binding protein 2 (FABP2; (p < 0.05) in the duodenum. Whereas dietary supplementation with MPD₂ improved the gastrointestinal morphology (p < 0.05); increased the total volatile fatty acid concentrations (p < 0.05); increased the expression of anti-inflammatory cytokine gene interleukin 10 (IL10; p < 0.05) and nutrient transporters SLC15A1 (p < 0.05), FABP2 (p < 0.05) and vitamin D receptor (VDR; p < 0.05); and reduced the expression of pro-inflammatory cytokine gene IL6 (p < 0.05), it adversely affected average daily feed intake (ADFI; p < 0.001) and average daily gain (ADG; p < 0.05). Mushroom powder supplementation had a positive impact on gastrointestinal morphology (p < 0.05) and upregulated the expression of nutrient transporters SLC15A1 (p < 0.05) and FABP2 (p < 0.05) and tight junction claudin 1 (CLDN1) (p < 0.05) compared to the controls but had no effect on the expression of inflammatory markers (p > 0.05). Furthermore, MP reduced ADFI (p < 0.01); however, this did not negatively impact the ADG (p > 0.05). In conclusion, MP and MPD₂ have limited use as commercial feed additives in replacing ZnO in pig diets as feed intake was reduced post-weaning.

This study was conducted to examine the effects of varying selenium (Se) inclusion levels, in the form of Se-enriched mushroom powder (SeMP) and selenite, on post-weaning growth performance (Period 1; day 1–21), intestinal health and antioxidant capacity (Period 2; day 21–39). Weaned pigs were blocked according to live weight, sex and litter of origin and randomly assigned to the following experimental groups: basal (basal + selenite (0.3 ppm Se)); ZnO (basal + ZnO + selenite (0.3 ppm Se)); 0.15 SeMP (basal + SeMP (0.15 ppm Se)); 0.3 SeMP (basal + SeMP (0.3 ppm Se)) and 0.6 SeMP/Sel (basal + SeMP (0.3 ppm Se) + selenite (Sel) (0.3 ppm Se)) with eight replicates/experimental group. After 21 days, the ZnO experimental group was removed from the experiment and the remaining pigs continued on their respective diet until day 39 post-weaning (Period 2). In Period 1, 0.15 SeMP supplementation reduced (p < 0.05) average daily gain (ADG), average daily feed intake (ADFI) and day 21 body weight, and increased (p < 0.05) faecal scores compared to the ZnO group. Supplementation with 0.3 SeMP and 0.6 SeMP/Sel during Period 1 resulted in similar (p > 0.05) ADG, ADFI, gain-to-feed ratio (G:F) and body weight compared to the ZnO group. However, 0.6 SeMP/Sel supplementation increased (p < 0.05) faecal scores compared to the ZnO group. In Period 2, 0.6 SeMP/Sel increased (p < 0.05) ADG, feed efficiency and day 39 body weight compared to the basal group. Supplementation with Se-enriched mushroom powder, at all inclusion levels, increased (p < 0.05) the abundance of Prevotellaceae and Prevotella, decreased (p < 0.05) the abundance of Sporobacter and increased (p < 0.05) the expression of SELENOP in the jejunum compared to the basal group. Lactobacillaceae and Lactobacillus was increased (p < 0.05) in 0.15 SeMP and 0.3 SeMP pigs compared to the basal group. Selenium deposition in muscle and liver tissue increased (p < 0.001) as a function of inclusion level while pigs supplemented with 0.3 ppm organic Se (0.3 SeMP) had an increase (p < 0.05) in total Se in the muscle compared to pigs supplemented with 0.3 ppm inorganic Se (basal). In conclusion, 0.3 SeMP supplementation led to positive effects on faecal scores and had similar pig performance compared to ZnO in Period 1, while the addition of 0.3 ppm selenite to 0.3 SeMP (0.6 SeMP/Sel) in Period 2 led to enhanced pig performance and aspects of gastrointestinal health.

A complete randomised block design experiment was conducted to examine the effects of mushroom powder (MP) and vitamin D₂‐enriched mushroom powder (MPD₂) on growth performance, faecal scores, coefficient of apparent total tract digestibility (CATTD) of nutrients and selected microflora in weaned pigs up to day 35 post‐weaning. One hundred and ninety‐two weaned pigs (7.8kg [SD 1.08kg]) were blocked according to live weight, sex and litter of origin and randomly assigned to the following: (T1) control diet; (T2) control diet +MP; (T3) control diet + MPD₂; and (T4) control diet +zinc oxide (ZnO) (n = 12 replicates/treatment). Mushroom powders were included at 2 g/kg of feed achieving a β‐glucan content of 200ppm. ZnO was included at 3100 mg/kg feed and halved to 1550 mg/kg after 21 days. Vitamin D content was enhanced in MPD₂ using synthetic UVB exposure to obtain a vitamin D₂ level of 100 µg/kg of feed. Faecal samples were collected on day 14 for microbial and nutrient digestibility analysis. There was no difference (p > 0.05) in ADG, G:F, faecal scores, microbial populations and CATTD of nutrients in pigs supplemented with MP or MPD₂ compared with the control diet. The supplementation of MP and MPD₂ caused a reduction (p < 0.05) in feed intake compared with the control and ZnO diet throughout the 35‐day experimental period. ZnO supplementation increased ADG and ADFI (p < 0.05) during the first period (D0‐21) compared with pigs offered MP and MPD₂. In conclusion, MP and MPD₂ supplementation resulted in similar ADG, G:F, faecal scores compared with the control but were not comparable to ZnO, mainly due to a reduction in feed intake.

This review examines the challenges faced by the pig industry, with a specific emphasis on improving the health and growth of weaned pigs. It emphasises the immediate necessity of investigating alternative approaches to managing pig nutrition and health due to restrictions on the use of antibiotics and the prohibition of zinc oxide in weaned pig diets. The weaning phase is identified as a critical stage in piglet development, characterized by stressors that affect their gastrointestinal health, immune responses, and overall physiology. The primary challenge during weaning arises from transitioning piglets from a digestible milk-based diet to a less digestible cereal-based feed, causing nutritional stress. This manifests as reduced feed intake, leading to gastrointestinal disturbances, intestinal inflammation, and adverse effects on intestinal structure and microbiota. To address these challenges and optimise piglet development, various nutritional strategies have been explored. Notably, glucans, particularly β-glucans from fungi, cereals, algae, and yeast, show promise in alleviating weaning-related issues. Furthermore, it's important to highlight the critical roles played by vitamin D and selenium in piglet nutrition. These essential nutrients can be sourced naturally from enriched mushrooms that are specifically enriched with vitamin D and selenium, providing a valuable dietary option. In conclusion, effective nutritional strategies, including glucans, vitamin D, selenium, and enriched mushrooms, are beneficial for addressing weaning-related challenges.