Tryptophan (Trp) supplementation has been shown to improve growth performance and enhance intestinal integrity in piglets. However, the effects of dietary Trp supplementation on the intestinal barrier function in piglets exposed to oxidative stress remain unknown. This study was conducted to evaluate whether dietary Trp supplementation can attenuate intestinal injury, oxidative stress, and mitochondrial dysfunction of piglets caused by diquat injection. Thirty-two piglets at 25 days of age were randomly allocated to four groups: (1) the non-challenged control; (2) diquat-challenged control; (3) 0.15% Trp-supplemented diet + diquat; (4) 0.30% Trp supplemented diet + diquat. On day seven, the piglets were injected intraperitoneally with sterilized saline or diquat (10 mg/kg body weight). The experiment lasted 21 days. Dietary supplementation with 0.15% Trp improved growth performance of diquat-challenged piglets from day 7 to 21. Diquat induced an increased intestinal permeability, impaired antioxidant capacity, and mitochondrial dysfunction. Although dietary supplementation with 0.15% Trp ameliorated these negative effects induced by diquat challenge that showed decreasing permeability of 4 kDa fluorescein isothiocyanate dextran, increasing antioxidant indexes, and enhancing mitochondrial biogenesis. Results indicated that dietary supplementation with 0.15% Trp enhanced intestinal integrity, restored the redox status, and improved the mitochondrial function of piglets challenged with diquat.

The objective of this experiment was to determine the effects of fiber level from alfalfa meal and collection period on intestinal nutrient and energy flow, and hindgut fermentation in growing pigs. Twenty-four pigs (initial BW = 21.4 ± 1.5 kg) were prepared by T-cannula insertion into the distal ileum and allotted to 4 treatments. The pigs were provided a corn-soybean meal control diet or a diet in which corn and soybean meal were partly replaced by 5%, 10%, or 20% alfalfa meal to give the graded levels of dietary fiber during two 10-d collection periods. The BW of pigs at the start of periods 1 and 2 were 32.2 ± 2.4 and 37.7 ± 4.2 kg, respectively. The final BW at the end of period 2 was 46.8 ± 4.0 kg. The apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients and energy were measured. The VFA concentration was also determined in the ileal and fecal samples. Nutrient digestibility was not affected by inclusion of 5% alfalfa meal in the diet. The AID, ATTD, and hindgut fermentation of DM, carbohydrates (CHO), and GE decreased (linear, P < 0.05) as the level of alfalfa meal in the diet increased. The intestinal flow of DM, CHO, ADF, and GE increased (linear, P < 0.05) by increasing the level of dietary alfalfa. The pH in ileal digesta and concentration of acetate, propionate, and total VFA in the feces increased (linear, P < 0.01) as the level of alfalfa meal in the diet increased. From experiment period 1 to 2, ATTD and hindgut fermentation of CHO decreased (P < 0.01), whereas concentrations of propionate, valerate, and total VFA in ileal samples increased (P < 0.05). A multiple linear regression analysis, taking into account both soluble dietary fiber and insoluble dietary fiber intake, explained the variation (P < 0.01) in total tract flow of NDF (93%), ADF (84%), GE (73%), DM (71%), and CHO (62%). In conclusion, the diet containing 5% of alfalfa meal did not affect nutrient and energy digestion. Intestinal flow of CHO decreased during the 10-d collection period. The VFA concentration increased with fiber level and 10-d exposure to the experimental diets. Soluble and insoluble fibers from alfalfa meal have differential roles in nutrient digestion, which may help explain the variation observed in the intestinal flow of nutrients.

Bioaerosols from swine confinement buildings (SCBs) pose a challenge to public health, and microorganisms within the SCBs bioaerosols originate from swine feces, of which the microbial composition is associated with the production phase. The present study adopted the whole metagenome shotgun sequencing approach, to assess the effects of the production phase on the composition and functional potential of microbial populations in SCBs bioaerosols. Most annotated proteins were assigned into domain bacteria, within which the predominant phylum was Firmicutes. The taxonomical profiles of bioaerosols from different types of piggeries showed that buildings housing weaning piglets (WP) exhibited higher abundances of Bacteroidetes and Proteobacteria than buildings housing finishing pigs (FP), gestating sows (GS), farrowing sows (FS), and breeding boars (BB). Regarding the functional potential, the WP bioaerosol had more genes involved in the protein turnover and fewer genes involved in the carbohydrate metabolism than bioaerosols from other types of SCBs. Furthermore, production phase influenced the antibiotic resistance genes (ARGs) profile of the SCBs bioaerosols. Bioaerosol microbiome of BB, shared a high similarity with GS, and WP bioaerosol microbiome was more similar to FP than other types of SCBs. Our study suggests that the production phase plays a key role in the SCBs bioaerosol microbiome.

The differences of pork quality characteristics among different pig breeds mainly came from the differences in myofiber type compositions. Growing evidence indicated the key role of miRNAs in myofiber specification. In the present study, we found that miR-152 is more abundant in the slow-twitch myofiber-enriched muscles. However, its role in myofiber type transformation and myogenesis is largely unknown. Overexpression of miR-152 in porcine myotubes promoted the formation of slow-twitch myofibers and myogenesis. While, inhibition of miR-152 expression showed the opposite effect to miR-152 mimics transfection. The luciferase reporter analysis confirmed that miR-152 straightly targets the 3′-untranslated region (3’-UTR) of uncoupling protein 3 (UCP3) to cause its post-transcriptional inhibition in the protein level. The knockdown of UCP3 by siRNA showed the similar effect of miR-152 on myofiber type transition. Furthermore, the rescue experiment in the porcine myotube transfected with miR-152 mimics or/and UCP3 overexpression plasmid with or without the 3’UTR revealed that UCP3 mediates the action of miR-152 in slow-twitch myofiber formation. Taken together, our findings proposed a novel molecular mechanism through which miR-152 epigenetically regulates meat quality via promoting slow-twitch myofiber formation and skeletal myogenesis.

Two experiments were conducted to determine the effects of viscosity and fermentability of purified nonstarch polysaccharides (NSP) on intestinal nutrient and energy flow and hindgut fermentation in growing pigs. In Exp. 1, 15 ileal-cannulated pigs (50.5 ± 2.9 kg BW) were allotted to 5 diets in a 2-period incompletely randomized design. Pigs were provided a cornstarch N-free diet (CST) or a diet containing 5% inulin (INU), carboxymethylcellulose sodium (CMC), microcrystalline cellulose (MCC), or Solka-Floc (SFC). Apparent ileal digestibility (AID) of DM, ash, and GE were greater (P < 0.05) in the MCC and SFC diets than in the INU and CMC diets. Apparent total tract digestibility (ATTD) of DM, carbohydrates (CHO), and GE and the DE content in the CST and INU diets were greater (P < 0.01) than in the CMC, MCC, and SFC diets. Hindgut disappearance of DM, CHO, and GE in the INU diet was greater (P < 0.05) than in the other N-free diets. The ileal endogenous flow of His, Ile, Leu, Met, Thr, Val, and all dispensable AA in the CMC diet was greater (P < 0.05) than in the other diets. In Exp. 2, 6 ileal-cannulated pigs were allotted to 3 diets containing either a corn–soybean meal control diet or the control diet with 5% INU or CMC in a replicated 3 × 3 Latin square design. Standardized ileal digestibility (SID) of Ala, Arg, Asp, Cys, Gly, His, Ile, Leu, Lys, Phe, Ser, Thr, and Val were greater (P < 0.05) in the CMC diet than in the control and INU diets. Incorporation of 5% INU or CMC in the control diet reduced (P < 0.01) the AID of arabinoxylan and insoluble and total NSP. The ATTD of NSP and cellulose and the hindgut disappearance of NSP, β-glucan, and cellulose in the CMC diet were less (P < 0.01) than in the control and INU diets. Inclusion of 5% INU in the diet increased (P < 0.01) hindgut fermentation of insoluble and total NSP compared with the control and CMC diets. In conclusion, depending on the viscosity and fermentability of the NSP, different sources will have different effects on nutrient digestibility and hindgut fermentation. Addition of 5% INU to a corn–soybean meal diet reduced digestibility of the NSP component in the ileum and increased hindgut fermentation of total NSP. In contrast, the inclusion of CMC increased the AID and SID of the diet and reduced total tract digestion and hindgut fermentation of NSP component. Carboxymethylcellulose sodium is not recommended as a source of synthetic fiber in a N-free diet to determine the SID of AA of diets.