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Simple Summary: Recent studies have shown a correlation between piglet diarrhea and the gut microbiota. However, the precise mechanism by which intestinal microorganisms and their metabolites influence diarrhea in weaned piglets remains unclear. This study explored differences in the gut microbiota and associated metabolites between healthy and diarrheic-weaned piglets using macrogenomic and metabolomic analyses. We identified microorganisms that differed markedly between the two groups. We noticed that the number and abundance of Bacteroidaceae bacterium were strongly negatively correlated with diarrhea in weaned piglets, whereas Caudoviricetes exhibited a strong positive correlation. Our screening for markedly different metabolites such as carnosine, pantothenic acid, pyridoxal, methylimidazoleacetic acid, indole-3-acetaldehyde and 5-hydroxyindoleacetic acid, along with the identification of metabolite-related metabolic pathways like tryptophan and vitamin B6 metabolism, identified important pathways associated with gut microbiota dysbiosis caused by post-weaning diarrhea in piglets. Conjoint analysis revealed that a substantial increase in the number and abundance of Caudoviricetes, coupled with a decrease in the number and abundance of Bacteroidaceae bacterium could potentially serve as microbial markers of post-weaning diarrhea. Recent studies have shown a correlation between piglet diarrhea and the gut microbiota. However, the precise mechanism by which intestinal microorganisms and their metabolites influence diarrhea in weaned piglets remains unclear. This study explored differences in the gut microbiota and associated metabolites between healthy and diarrheic-weaned piglets using macrogenomic and metabolomic analyses. The histomorphological results showed that diarrheic piglets had shorter jejunal and ileal villi, some of which were shed, compared to healthy piglets. Substantial differences in gut microbial diversity and metabolites were also observed, with Bacteroidaceae bacterium and Caudoviricetes being the main differential organisms that were strongly correlated with host status. Microbial functions, mainly the metabolism of carbohydrates, glycans, lipids, and amino acids, as well as related enzyme activities, were substantially different. The major differential metabolites were carnosine, pantothenic acid (vitamin B5), pyridoxal, methylimidazoleacetic acid, indole-3-acetaldehyde, and 5-hydroxyindoleacetic acid. These metabolites were enriched in beta-alanine, histidine, tryptophan, and vitamin B6 metabolism, and in the pantothenate and CoA biosynthesis pathways. Combined macrogenomic and metabolomic analyses revealed that carnosine, vitamin B5, and pyridoxal were negatively correlated with Caudoviricetes; methylimidazoleacetic acid, indole-3-acetaldehyde, and 5-hydroxyindoleacetic acid were positively correlated with Caudoviricetes. Whereas carnosine and vitamin B5 were positively correlated with Bacteroidaceae bacterium, 5-hydroxyindoleacetic acid was negatively correlated. The decreased abundance of Bacteroidaceae bacterium and the increased abundance of Caudoviricetes and related metabolites likely contribute to post-weaning diarrhea in piglets. Therefore, the abundance of Bacteroidaceae bacterium and Caudoviricetes can likely serve as potential markers for identifying and preventing diarrhea in post-weaning piglets. [ABSTRACT FROM AUTHOR]

Chinese indigenous pig and Western commercial pig breeds show different patterns of lipid metabolism, fat deposition, and fatty acid composition; for these reasons, they have become vitally important models of energy metabolism and obesity in humans. To compare the mechanisms underlying lipid metabolism between Yorkshire pigs (lean type) and Anqing six-end-white pigs (obese type), the liver transcriptomes of six castrated boars with a body weight of approximately 100 kg (three Yorkshire and three Anqing) were analyzed by RNA-seq. The total number of reads produced for each liver sample ranged from 47.05 to 62.6 million. Among 362 differentially expressed genes, 142 were up-regulated and 220 were down-regulated in Anqing six-end-white pigs. Based on these data, 79 GO terms were significantly enriched. The top 10 (the 10 with lowest corrected P-value) significantly enriched GO terms were identified, including lipid metabolic process and carboxylic acid metabolic process. Pathway analysis revealed three significantly enriched KEGG pathways including PPAR signaling pathway, steroid hormone biosynthesis, and retinol metabolism. Based on protein-protein interaction networks, multiple genes responsible for lipid metabolism were identified, such as PCK1, PPARA, and CYP7A1, and these were considered promising candidate genes that could affect porcine liver lipid metabolism and fat deposition. Our results provide abundant transcriptomic information that will be useful for animal breeding and biomedical research. Key words: pig, liver, transcriptome sequencing, lipid metabolism. Resume : Les races indigenes chinoises et commerciales occidentales presentent des differences dans le metabolisme des lipides, les depots adipeux et la composition en acides gras; pour ces raisons, ils sont devenus des modeles pour l'etude du metabolisme energetique et l'obesite chez les humains. Pour comparer les mecanismes expliquant les differences metaboliques entre les porcs Yorkshire (maigre) et Anqing six-end-white (obese), les transcriptomes hepatiques de six verrats castres dont la masse corporelle etait d'environ 100 kg (trois Yorkshire et trois Anqing) ont ete analyses par une approche RNA-seq. Le nombre total de sequences produites pour chaque echantillon hepatique variait entre 47,05 et 62,6 millions. Parmi 362 genes exprimes differemment, 142 et 220 etaient respectivement exprimes plus ou moins fortement chez les porcs Anqing six-end-white. Sur la base de ces donnees, il a ete observe que 79 termes GO etaient enrichis. Les premiers 10 termes enrichis (ceux avec la valeur P corrigee la plus faible) ont ete identifies et incluaient le metabolisme lipidique et le metabolisme de l'acide carboxylique. Une analyse des sentiers a revele un enrichissement significatif de trois sentiers KEGG dont la signalisation PPAR, la synthese des hormones steroidiennes et le metabolisme du retinol. Sur la base des reseaux d'interactions proteine-proteine, plusieurs genes impliques dans le metabolisme des lipides ont ete identifies tels que PCK1, PPARA et CYP7A1; ceux-ci sont consideres comme etant des genes candidats prometteurs pouvant affecter le metabolisme lipidique chez le foie et les depots adipeux chez le porc. Ces resultats fournissent une riche information transcriptomique qui sera utile en amelioration genetique et en recherche biomedicale. [Traduit par la Redaction] Mots-cles : porc, foie, sequencage du transcriptome, metabolisme des lipides., Introduction Obesity is an epidemic disease and correlates with cardiovascular diseases, which increase overall mortality and has become a major threat to the quality of life for humans (Abarca-Gomez et [...]