Muscle characteristics in chicks challenged with Salmonella Enteritidis and the effect of preventive application of the probiotic Enterococcus faecium

Impaired muscle stem cell function and abnormal myogenesis in acquired myopathies

Skeletal muscle possesses a high plasticity and a remarkable regenerative capacity that relies mainly on muscle stem cells (MuSCs). Molecular and cellular components of the MuSC niche, such as immune cells, play key roles to coordinate MuSC function and to orchestrate muscle regeneration. An abnormal infiltration of immune cells and/or imbalance of pro- and anti-inflammatory cytokines could lead to MuSC dysfunctions that could have long lasting effects on muscle function. Different genetic variants were shown to cause muscular dystrophies that intrinsically compromise MuSC function and/or disturb their microenvironment leading to impaired muscle regeneration that contributes to disease progression. Alternatively, many acquired myopathies caused by comorbidities (e.g., cardiopulmonary or kidney diseases), chronic inflammation/infection, or side effects of different drugs can also perturb MuSC function and their microenvironment. The goal of this review is to comprehensively summarize the current knowledge on acquired myopathies and their impact on MuSC function. We further describe potential therapeutic strategies to restore MuSC regenerative capacity.

The Changes in Microbiotic Composition of Different Intestinal Tracts and the Effects of Supplemented Lactobacillus During the Formation of Goose Fatty Liver

Intestinal bacteria play an important role in the formation of fatty liver in animals by participating in the digestion and degradation of nutrients, producing various metabolites, and altering the barrier effect of the intestine. However, changes in the gut microbiota during the formation of goose fatty liver are unclear. In this study, 80 healthy Landes geese with similar body weights at 70 days of age were randomly divided into two groups: the control group (n = 48; fed ad libitum) and the overfeeding group (n = 32; overfed). The intestinal contents were collected at 0, 12, and 24 days of overfeeding. The 16S rRNA and metagenomic sequencing analyses showed that the dominant phyla were Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria. At the genus level, Phyllobacterium, Bacteroides, Helicobacter, Lactobacillus, Enterococcus, and Romboutsia were the dominant genera in the goose intestine, and most of them were probiotics. In the control group, the relative abundance of Firmicutes in the jejunum and ileum gradually decreased with time, while that of Proteobacteria increased, whereas in the overfeeding group, the relative abundance of Firmicutes in the jejunum and ileum decreased and then increased with time, while that of Proteobacteria showed an opposite trend. In addition, supplementing Lactobacillus to the diet reduced body weight and fatty liver weight in overfed geese, but increased the weight of abdominal fat, suggesting that Lactobacillus supplementation might affect the transport of nascent fat from the liver to abdominal fat. In conclusion, the species of intestinal-dominant bacteria in the geese are relatively stable, but their relative abundance and function are affected by a number of factors. Overfeeding promotes the metabolism of nutrients in the jejunum and ileum and increases bacterial adaptability to environmental changes by enhancing their ability to process environmental and genetic information more efficiently. These findings suggest that the effect of overfeeding on the composition of intestinal microbiota may indirectly influence the formation of goose fatty liver through the gut/liver axis.

Dissemination of Quinupristin-Dalfopristin and Linezolid resistance genes among hospital environmental and healthy volunteer fecal isolates of Enterococcus faecalis and Enterococcus faecium

BACKGROUND

Streptogramins and linezolid are important in the treatment of infections caused by vancomycin-resistant enterococci.

PURPOSE

Then, we aimed to evaluate the resistance rates against these drugs and the prevalence of genes involved in hospital environmental and fecal normal-flora isolates of Enterococcus faecalis and Enterococcus faecium.

METHODS AND RESULTS

The strains were isolated from the stool samples and hospital environments by culturing on M-Enterococcus (ME) agar, and identified by phenotypic and genotypic microbiological tests. The disk agar diffusion method was used to identify the antimicrobial susceptibility pattern of the isolates. The genomic DNA extraction was done by the alkaline lysis method, and the PCR test was used to detect the resistance genes. A total of 145 enterococci isolates were taken, from which 84 (57.9%) isolates were detected as E. faecalis and 61 (42.06%) isolates were E. faecium. Moreover, 70 (83.33), 4 (4.76%), 1 (1.19%), and 40 (47.61%) isolates of E. faecalis and 20 (32.78%), 1 (1.63%), 4 (6.55%), and 26 (42.62%) E. faecium isolates were resistant against quinupristin-dalfopristin, linezolid, vancomycin, and erythromycin, respectively. Also, 112 (77.24%), 50 (34.48%), 39 (26.89%), 27 (18.62%), 19 (13.1%), 4 (2.75%), and 1 (0.68%) isolates were contained LsaA, vatD, vgbB, vatE, cfr, lsaE and optrA genes, respectively. None of the isolates carried the vgbA gene.

CONCLUSIONS

High-level streptogramin resistance rate and high prevalence of resistance genes in enterococci isolated from the stool of healthy persons and the hospital environment indicates the importance of possible transmission of resistance genes from these isolates to clinical ones.

Influence of Lacto-Immuno-Vital on growth performance and gene expression of IgA, MUC-2, and growth factor IGF-2 in the jejunum of broiler chickens

The effects of Lacto-Immuno-Vital synbiotic preparation on gene expression of IgA, MUC-2, and growth factor IGF-2 in the jejunum and on BW gain in broiler chickens were studied. A flock of 64,400 1-day-old Hybrid ROSS 308 chickens was inducted in the 42-day experiment. The chickens were divided into 2 equally size groups in separate halls. The chickens in the experimental (E) group received 500 g of Lacto-Immuno-Vital in 1,000 L of drinking water. The preparation was administered daily from the first day (day 1) to day 7 of the experiment. From day 7 to day 22, it was given in pulsed manner (every third day) at a dose of 300 g in 1,000 L of drinking water. The broiler chickens in the E group gained more weight (P < 0.001) compared with control from day 10 to day 42. Death of animals during feeding period was 1,078 chickens in the E group compared with 1,115 dead chickens in the control group. Feed conversion ratio was 1.61 kg of supplemented diet/kg of BW in the E group compare with 1.67 kg of nonsupplemented diet/kg of BW in control. The relative expression of IgA gene in the jejunum was upregulated on day 22 in the E group compared with control (P < 0.05), whereas relative expression of MUC-2 gene was upregulated in the E group compared with control on day 8 and day 22 (P < 0.05; P < 0.001). Similarly, relative expression of IGF-2 gene was upregulated in the E group compared with control on both samplings (P < 0.01). The composition of Lacto-Immuno-Vital synbiotic preparation showed beneficial effects on growth performance, feed conversion ratio, morbidity, mortality, and selected parameters of mucosal immunity in the chicken jejunum.

Effects of Oral Glutamine Supplementation on Early Postnatal Muscle Morphology in Low and Normal Birth Weight Piglets

Adapted nutrition can improve the growth of low birth weight (LBW) piglets. Since maternal milk is thought to provide insufficient glutamine (Gln) for LBW piglets, the current study investigated the influence of Gln supplementation during the early suckling period on development and lipid deposition in skeletal muscle. The weight differences between LBW and normal birth weight (NBW) littermates persisted from birth to slaughter (p < 0.001). However, intramuscular Gln and Ala concentrations were altered in piglets according to the supplementation (p < 0.01). There were larger muscle fibers (p = 0.048) in Gln-supplemented piglets. Capillarization or nuclei number per muscle fiber was not influenced by birth weight (BiW) or Gln supplementation. Abundance of myosin heavy chain (MYH) isoforms was slightly altered by Gln supplementation. LBW piglets had more lipid droplets than NBW piglets at day 5 of life in both muscles (p < 0.01). The differences decreased with age. Adipocyte development increased with age, but was not influenced by BiW or supplementation. The results indicate that BiW differences were accompanied by differences in lipid deposition and muscle fiber structure, suggesting a delayed development in LBW piglets. Supplementation with Gln may support piglets to overcome those disadvantages.

Consequences of Maternal Essential Fatty Acid and Conjugated Linoleic Acid Supplementation on the Development of Calf Muscle and Adipose Tissue

Common silage and concentrate-based diets in dairy and beef production may deliver insufficient amounts of essential fatty acids (EFA), thereby also reducing conjugated linoleic acids (CLA) in body tissues and milk. An impaired maternal EFA and CLA supply can have an important impact on calf postnatal development. The current study investigates how maternal supplementation with EFA and CLA affects muscle and adipose tissue development in neonatal calves. Holstein cows (n = 40) were abomasaly supplemented with coconut oil (control), CLA or EFA, or both combined during the transition period. Calves were fed their dam's colostrum until slaughter at day 5 of life. Fatty acid composition and tissue morphology were analyzed. In muscle and adipose tissues, EFA, CLA, and metabolites were elevated, indicating the effective transfer of maternally-supplemented FA to the offspring. Muscle fiber types, fiber nuclei, myosin heavy chain isoform distribution, capillarization, and fat cell size of intramuscular and other adipose tissues did not differ among groups. The results confirm that maternal nutrition during the transition period can alter the FA composition of the calf tissues. This could influence the offspring's development and health in the long-term, even though only minor effects were observed in the neonatal calves' tissue morphology.