Guanidinoacetic acid ameliorates hepatic steatosis and inflammation and promotes white adipose tissue browning in middle-aged mice with high-fat-diet-induced obesity.

Guanidinoacetic acid (GAA) is a naturally occurring amino acid derivative that plays a critical role in energy metabolism. In recent years, a growing body of evidence has emerged supporting the importance of GAA in metabolic dysfunction. Hence, we aimed to investigate the effects of GAA on hepatic and adipose tissue metabolism, as well as systemic inflammatory responses in obese middle-aged mice models and attempted to explore the underlying mechanism. We found that dietary supplementation of GAA inhibited inguinal white adipose tissue (iWAT) hypertrophy in high-fat diet (HFD)-fed mice. In addition, GAA supplementation observably decreased the levels of some systemic inflammatory factors, including IL-4, TNF-α, IL-1ß, and IL-6. Intriguingly, GAA supplementation ameliorated hepatic steatosis and lipid deposition in HFD-fed mice, which was revealed by decreased levels of TG, TC, LDL-C, PPARγ, SREBP-1c, FASN, ACC, FABP1, and APOB and increased levels of HDL-C in the liver. Moreover, GAA supplementation increased the expression of browning markers and mitochondrial-related genes in the iWAT. Further investigation showed that dietary GAA promoted the browning of the iWAT via activating the AMPK/Sirt1 signaling pathway and might be associated with futile creatine cycling in obese mice. These results indicate that GAA has the potential to be used as an effective ingredient in dietary interventions and thus may play an important role in ameliorating and preventing HFD-induced obesity and related metabolic diseases.

Vitamin a potentiates sheep myoblasts myogenic differentiation through BHLHE40-modulated ID3 expression.

BACKGROUND: Vitamin A and retinoic acid (RA, a metabolite of vitamin A), are inextricably involved to the development of skeletal muscle in animals. However, the mechanisms regulating skeletal muscle development by vitamin A remain poorly reported. The current study designed to investigate the underlying mechanism of vitamin A affecting myogenic differentiation of lamb myoblasts through transcriptome sequencing (RNA-Seq) and gene function validation experiments. It provides a theoretical basis for elucidating the regulation of vitamin A on skeletal muscle development as well as for improving the economic benefits of the mutton sheep industry. RESULTS: Newborn lambs were injected with 7,500 IU vitamin A, and longissimus dorsi (LD) muscle tissue was surgically sampled for RNA-Seq analysis and primary myoblasts isolation at 3 weeks of age. The results showed that a total of 14 down-regulated and 3 up-regulated genes, were identified between control and vitamin A groups. Among them, BHLHE40 expression was upregulated in vitamin A group lambs. Furthermore, BHLHE40 expression is significantly increased after initiation of differentiation in myoblasts, and RA addition during differentiation greatly promoted BHLHE40 mRNA expression. In vitro, RA inhibited myoblasts proliferation and promoted myoblasts myogenic differentiation through BHLHE40. Moreover, BHLHE40 was proved to inhibit the expression of the DNA binding inhibitor 3 (ID3), and meanwhile, ID3 could effectively promote myoblasts proliferation and inhibit myoblasts myogenic differentiation. CONCLUSIONS: Taken together, our results suggested that vitamin A inhibited myoblasts proliferation and promoted myoblasts myogenic differentiation by inhibiting ID3 expression through BHLHE40.

First Report of Brown Rot Caused by Monilia yunnanensis on Sweet Cherry in China.

Chinese cherry industry has developed rapidly over the past few years, with the planting acreage continuously expanding, from Shandong province to Liaoning, Shaanxi, Hebei, Sichuan etc. Monilia spp. are the most important causal agents of brown rot of cherry, to date, M. fructicola, M. mumecola, and M. fructigena were reported to cause brown rot of cherry in China (Chen et al. 2013; Yin et al. 2014; Liu et al. 2012). In May 2023, fruit of sweet cherry cultivar 'Hongdeng' (Prunus avium L.) with symptoms resembling brown rot were collected from Tongchuan City, Shaanxi Province. Conidia on diseased tissues were spread on a water agar (WA, 1.5% agar and distilled water) medium and isolated with a glass needle under a professional single spore separation microscope (Wuhan Heipu Science and Technology Ltd., Wuhan, China). If no conidia were present, fruit pieces (5 × 5 mm) at the intersection of healthy and diseased tissues were surface sterilized with a sodium hypochlorite solution (1%) for 30 s and washed three times in sterilized water, followed by 75% ethanol for 30 s, then washed three times in sterilized water. After the tissue pieces were dried, they were placed on potato dextrose agar (PDA; 200 g of potato, 20 g of dextrose, and agar at 20 g/L) and incubated at 22 °C for about twenty days to produce spores and then single spore isolation was carried out. Thirty single-spore isolates were obtained and all were morphologically similar. The isolates produced white-gray colonies with even margins and concentric rings of sporogenous mycelium after 3 days incubation, and abundant black-colored stromata on the PDA medium after 15 days of incubation at 22°C. Conidia were one-celled, hyaline, ellipsoid to lemon shape (14.12 × 10.37 µm), with 1-2 germs which is similar to M. yunnanensis on peach. The genomic DNA of the isolates was extracted as described previously (Chi et al. 2009). The pathogen identity was confirmed by multiplex PCR which resulted in a 237bp amplicon, which is diagnostic of M. yunnanensis (Hu et al. 2011). Further sequencing of the internal transcribed spacer (ITS) region 1 and 2 and 5.8S gene (accession number: OR192774) indicated 100% identity with that of M. yunnanensis isolates (accession numbers: MW355895, ON024742). The average daily growth of mycelium on PDA at 22°C was 11.44 mm. Koch's postulates were fulfilled by inoculating 20 mature sweet cherry fruits of cv. 'Van' with mycelial plugs in a drilled hole. After 3 days of incubation at 22℃ in an airtight plastic tray with wet paper, the inoculated fruit developed typical brown rot symptoms. The developing spores on inoculated fruit were confirmed to be M. yunnanensis based on ITS sequence. All control fruit inoculated with a PDA plug remained healthy. M. yunnanensis was first reported as the causal agent of brown rot of peach in China (Hu et al. 2011). Later studies demonstrated that it is also pathogen on other fruits, e.g. hawthorn (Zhao et al. 2013), plum (Yin et al. 2015), apricot (Yin et al. 2017), apple, and pear in China (Zhu et al. 2016). To our knowledge, this is the first report of cherry brown fruit rot caused by M. yunnanensis, indicating the high risk of this species to cherry production, and effective strategies must be taken to prevent the possible control failure in practice.

Diversity and potential function of pig gut DNA viruses.

Viruses are ubiquitous in the gut of animals and play an important role in the ecology of the gut microbiome. The potential effects of these substances on the growth and development of the body are not fully known. Little is known about the effects of breeding environment on pig gut virome. Here, there are 3584 viral operational taxonomic units (vOTUs) longer than 5 kb identified by virus-enriched metagenome sequencing from 25 pig fecal samples. Only a small minority of vOTUs (11.16%) can be classified at the family level, and ∼50% of the genes could be annotated, supporting the concept of pig gut as reservoirs of substantial undescribed viral genetic diversity. The composition of pig gut virome in the six regions may be related to geography. There are only 20 viral clusters (VCs) shared among pig gut virome in six regions of Shanxi Province. These viruses rarely carry antibiotic resistance genes (ARGs). At the same time, they possess abundant auxiliary metabolic genes (AMGs) potentially involved in carbon, sulfur metabolism and cofactor biosynthesis, etc. This study has revealed the unique characteristics and potential function of pig gut DNA virome and established a foundation for the recognition of the viral roles in gut environment.

Metagenomic analysis reveals patterns and hosts of antibiotic resistance in different pig farms.

In actual production environments, antibiotic-resistant genes (ARGs) are abundant in pig manure, which can form transmission chains through animals, the environment, and humans, thereby threatening human health. Therefore, based on metagenomic analysis methods, ARGs and mobile genetic elements (MGEs) were annotated in pig manure samples from 6 pig farms in 3 regions of Shanxi Province, and the potential hosts of ARGs were analyzed. The results showed that a total of 14 ARG types were detected, including 182 ARG subtypes, among which tetracycline, phenol, aminoglycoside, and macrolide resistance genes were the main ones. ARG profiles, MGE composition, and microbial communities were significantly different in different regions as well as between different pig farms. In addition, Anaerobutyricum, Butyrivibrio, and Turicibacter were significantly associated with multiple ARGs, and bacteria such as Prevotella, Bacteroides, and the family Oscillospiraceae carried multiple ARGs, suggesting that these bacteria are potential ARG hosts in pig manure. Procrustes analysis showed that bacterial communities and MGEs were significantly correlated with ARG profiles. Variation partitioning analysis results indicated that the combined effect of MGEs and bacterial communities accounted for 64.08% of resistance variation and played an important role in ARG profiles. These findings contribute to our understanding of the dissemination and persistence of ARGs in actual production settings, and offer some guidance for the prevention and control of ARGs contamination.

Integrated Omics Analysis Reveals Alterations in the Intestinal Microbiota and Metabolites of Piglets After Starvation.

Obesity is a serious public health problem. Short-term starvation is an effective way to lose weight but can also cause harm to the body. However, a systematic assessment of the relationship between the intestinal microbiota and metabolites after complete fasting is lacking. Pigs are the best animal models for exploring the mechanisms of human nutrition digestion and absorption, metabolism, and disease treatment. In this study, 16S rRNA sequencing and liquid chromatography-mass spectrometry were used to analyze the changes in the intestinal microbiota and metabolite profiles in piglets under starvation stress. The results show that the microbial composition was changed significantly in the starvation groups compared with the control group (P < 0.05), suggesting that shifts in the microbial composition were induced by starvation stress. Furthermore, differences in the correlation of the intestinal microbiota and metabolites were observed in the different experimental groups. Starvation may disrupt the homeostasis of the intestinal microbiota and metabolite profile and affect the health of piglets. However, piglets can regulate metabolite production to compensate for the effects of short-term starvation. Our results provide a background to explore the mechanism of diet and short-term hunger for intestinal homeostasis.