Identification of porcine fast/slow myogenic exosomes and their regulatory effects on lipid accumulation in intramuscular adipocytes

Background Pork quality is affected by the type of muscle fibers, which is closely related to meat color, tenderness and juiciness. Exosomes are tiny vesicles with a diameter of approximately 30–150 nm that are secreted by cells and taken up by recipient cells to mediate communication. Exosome-mediated muscle-fat tissue crosstalk is a newly discovered mechanism that may have an important effect on intramuscular fat deposition and with that on meat quality. Various of adipose tissue-derived exosomes have been discovered and identified, but the identification and function of muscle exosomes, especially porcine fast/slow myotube exosomes, remain unclear. Here, we first isolated and identified exosomes secreted from porcine extensor digitorum longus(EDL) and soleus(SOL), which represent fast and slow muscle, respectively, and further explored their effects on lipid accumulation in longissimus dorsi adipocytes.Results Porcine SOL-derived exosomes(SOL-EXO) and EDL-derived exosomes(EDL-EXO) were first identified and their average particle sizes were approximately 84 nm with double-membrane disc-shapes as observed via transmission electron microscopy and scanning electron microscopy. Moreover, the intramuscular fat content of the SOL was greater than that of the EDL at 180 days of age, because SOL intramuscular adipocytes had a stronger lipid-accumulating capacity than those of the EDL. Raman spectral analysis revealed that SOL-EXO protein content was much greater than that of EDL-EXO. Proteomic sequencing identified 72 proteins that were significantly differentially expressed between SOL-EXO and EDL-EXO, 31 of which were downregulated and 41 of which were upregulated in SOL-EXO.Conclusions Our findings suggest that muscle-fat tissue interactions occur partly via SOL-EXO promoting adipogenic activity of intramuscular adipocytes.

Soil properties and not plant factors affect both abundant and rare microbial taxa after thinning in a mixed stand of Cunninghamia lanceolata and Sassafras tzumu

Thinning is an effective management step for sustainable forest development,yet less attention is paid to the restoration of soil microbiota after thinning.In this study,both abundant and rare soil microbial communities(i.e.,bacterial,fungal),were evaluated under various thinning treatments in a mixed stand of Cunninghamia lanceolata and Sassafras tzumu using Mi Seq sequencing.Thinning did not significantly change either abundant or rare bacterial and fungal community composition,but affected their alpha diversity.The Shannon–Wiener indexes of rare fungal taxa under medium thinning were significantly lower than in the light thinning(P<0.05 level).Xanthobacteraceae dominated the abundant bacterial taxa,and Saitozyma and Mortierlla the abundant fungal taxa.The most common rare bacterial taxa varied;there was no prevalent rare fungal taxa under different thinnings.In addition,soil available nitrogen,total phosphorus,and p H had significant effects on rare bacterial taxa.Nutrients,especially available phosphorus,but not nitrogen,affected abundant and rare soil fungi.The results indicate that soil properties rather than plant factors affect abundant and rare microbial communities in soils of mixed stands.Thinning,through mediating soil properties,influences both abundant and rare bacterial and fungal communities in the mixed C.lanceolata and S.tzumu stand.

Dietary bile acid supplementation in weaned piglets with intrauterine growth retardation improves colonic microbiota,metabolic activity,and epithelial function

Background Intrauterine growth retardation(IUGR)is one of the major constraints in animal production.Our previ-ous study showed that piglets with IUGR are associated with abnormal bile acid(BA)metabolism.This study explored whether dietary BA supplementation could improve growth performance and colonic development,function,micro-biota,and metabolites in the normal birth weight(NBW)and IUGR piglets.A total of 48 weaned piglets(24 IUGR and 24 NBW)were allocated to four groups(12 piglets per group):(i)NBW group,(ii)NBW+BA group,(iii)IUGR group,and(iv)IUGR+BA group.Samples were collected after 28 days of feeding.Results The results showed that dietary BA supplementation increased the length and weight of the colon and colon weight to body weight ratio,while decreased the plasma diamine oxidase(DAO)concentration in the NBW pig-lets(P<0.05).Dietary BA supplementation to IUGR piglets decreased(P<0.05)the plasma concentrations of D-lactate and endotoxin and colonic DAO and endotoxin,suggesting a beneficial effect on epithelial integrity.Moreover,dietary BA supplementation to NBW and IUGR piglets increased Firmicutes abundance and decreased Bacteroidetes abundance(P<0.05),whereas Lactobacillus was the dominant genus in the colon.Metabolome analysis revealed 65 and 51 differential metabolites in the colon of piglets fed a diet with/without BA,respectively,which was associated with the colonic function of IUGR piglets.Furthermore,dietary BA supplementation to IUGR piglets upregulated the expressions of CAT,GPX,SOD,Nrf1,IL-2,and IFN-γin colonic mucosa(P<0.05).Conclusions Collectively,dietary BA supplementation could improve the colonic function of IUGR piglets,which was associated with increasing proportions of potentially beneficial bacteria and metabolites.Furthermore,BA shows a promising application prospect in improving the intestinal ecosystem and health of animals.

Intrauterine growth retardation affects liver bile acid metabolism in growing pigs:effects associated with the changes of colonic bile acid derivatives

Background:Intrauterine growth retardation(IUGR)is associated with severely impaired nutrient metabolism and intestinal development of pigs.Our previous study found that IUGR altered intestinal microbiota and metabolites in the colon.However,the consequences of IUGR on bile acid metabolism in pigs remained unclear.The present study aimed to investigate the bile acid metabolism in the liver and the profile of bile acid derivatives in the colon of grow-ing pigs with IUGR using bile acid targeted metabolomics.Furthermore,we determined correlations between colonic microbiota composition and metabolites of IUGR and normal birth weight(NBW)pigs at different growth stages that were 7,21,and 28-day-old,and the average body weight(BW)of 25,50,and 100 kg of the NBW pigs.Results:The results showed that the plasma total bile acid concentration was higher(P<0.05)at the 25 kg BW stage and tended to increase(P=0.08)at 28-day-old in IUGR pigs.The hepatic gene expressions related to bile acid synthe-sis(CYP7A1,CYP27A1,and NTCP)were up-regulated(P<0.05),and the genes related to glucose and lipid metabolism(ATGL,HSL,and PC)were down-regulated(P<0.05)at the 25 kg BW stage in IUGR pigs when compared with the NBW group.Targeted metabolomics analysis showed that 29 bile acids and related compounds were detected in the colon of pigs.The colonic concentrations of dehydrolithocholic acid and apocholic acid were increased(P<0.05),while isodeoxycholic acid and 6,7-diketolithocholic acid were decreased(P<0.05)in IUGR pigs,when compared with the NBW pigs at the 25 kg BW stage.Moreover,Spearman’s correlation analysis revealed that colonic Unclassified_[Mogi-bacteriaceae],Lachnospira,and Slackia abundances were negatively correlated(P<0.05)with dehydrolithocholic acid,as well as the Unclassified_Clostridiaceae abundance with 6,7-diketolithocholic acid at the 25 kg BW stage.Conclusions:These findings suggest that IUGR could affect bile acid and glucolipid metabolism in growing pigs,especially at the 25 kg BW stage,these effects being paralleled by a modification of bile acid derivatives concentra-tions in the colonic content.The plausible links between these modified parameters are discussed.

Anti-Inflammatory Effect of Dendrobium Huoshanense Polysaccharides on Carrageenan-Induced Air Pouch Synovitis in Mice

Objective:The purpose was to observe the anti-inflammatory effects of Dendrobium huoshanense polysaccharides(DHPs)on carrageenan-induced sterile air pouch synovitis.Materials and Methods:A total of 30 Institute of Cancer Research(ICR)mice were randomly and equally assigned to the control,carrageenan-induced air pouch synovitis model(model),and carrageenan-induced air pouch synovitis model+DHP(200 mg/kg of body weight)(model+DHP)groups.Mice in the model+DHP group were intragastrically administered 200 mg/kg BW of DHP solution daily for 10 days.Mice in the control and model groups were intragastrically administered the same amount of distilled water.Two hours after intragastric administration on day 10,1 mL of a 1%carrageenan solution in a sterile 0.9%saline solution was injected into the air pouch of mice in the model and model+DHP groups.Six hours later,the mice were sacrificed and 4 mL of ice-cold sterile 0.9%saline solution was injected into the air pouch to fully wash its inner wall.The lavage fluid was collected to observe the color and turbidity of the lavage fluid,as well as the appearance of the backside of the air pouch.The exudate volume,total number of leukocytes,protein content,levels of malondialdehyde(MDA),interleukin-1β(IL-1β),and tumor necrosis factor-alpha(TNF-α),and total superoxide dismutase(T-SOD)activity of the lavage fluid were analyzed.Results:The results showed that pretreatment with DHPs reduced the carrageenan-induced exudate volume(P<0.01),total leukocytes(P<0.05),and protein content(P<0.01)in the air pouch lavage fluid.Furthermore,mice in the model+DHP group had significantly higher(P<0.01)T-SOD activity and lower MDA content(P<0.05),IL-1β(P<0.05),and TNF-α(P<0.01)levels in the air pouch lavage fluid compared with the model group.Conclusion:It is concluded that DHPs partially alleviated carrageenan-induced sterile inflammation,and its mechanism may be related to reducing exudation and scavenging oxygen-free radicals,inhibiting lipid peroxidation,and reducing the level of the proinflammatory factors,such as IL-1βand TNF-α.