Resistance of rumen bacteria murein to bovine gastric lysozyme

Effects of Dietary Supplementation of Essential Oils, Lysozyme, and Vitamins' Blend on Layer Hen Performance, Viral Vaccinal Response, and Egg Quality Characteristics

Maintaining respiratory tract health is crucial for layers, impacting gut health, laying performance, and egg quality. Viral diseases and standard vaccinations can compromise tracheal epithelium function, leading to oxidative stress. This study assessed the impact of a blend of feed additives, predominantly lysozyme (L), essential oils (EO), and vitamins (VIT) (referred to as L + EO + VIT), on young layers during an oral vaccination schedule. The supplementation significantly enhanced antibody titers for Newcastle Disease Virus (NDV) and Infectious Bronchitis Virus (IBV) after vaccination, trachea functionality and intestinal health in the jejunum, increased egg production, and exhibited a trend toward higher egg weight. Although feed intake showed no significant difference, egg quality remained consistent across experimental groups. Moreover, L + EO + VIT supplementation elevated total phenolic content in eggs, improving oxidative stability in both fresh and stored eggs, particularly under iron-induced oxidation. Notably, it substantially reduced yolk lipid peroxidation and albumen protein carbonyls. In conclusion, water supplementation with L + EO + VIT may enhance humoral immune response to IBV and NDV, positively impacting hen productivity. These findings indicate improved tracheal function and enhanced oxidative stability, emphasizing the potential of this blend in promoting overall health and performance in layers.

Protective effect of additional cathelicidin antimicrobial peptide PR-39 on prosthetic-joint infections

BACKGROUND

Prosthetic-joint infection (PJI) is one of the severest complications after arthroplasty. However, antibiotics are not effective in the bacteria in biofilm outside the prosthetic-joint. Antimicrobial peptides have an efficient antimicrobial activity in staphylococcus aureus compared with conventional antibiotics.

METHODS

Bone marrow stem cells (BMSCs) were isolated, cultured and transfected with cathelicidins antimicrobial peptides proline-arginine-rich 39 amino acid peptide (PR-39) lentivirus. The expression of PR-39 gene in BMSCs was detected by RT-PCR, and the antibacterial activity of PR-39 was measured by agar diffusion method. The transfection efficiency was detected by fluorescence microscopy. The infection model of artificial knee joint in rabbits were established. Kirschner wire was used as the knee joint implant to implant the distal femur through the femoral intercondylar fossa of rabbits. 24 rabbits were randomly divided into 2 groups for the above operations: group A was inoculated 0.5 mL into the joint cavity immediately after the incision was sutured 1 × 10⁷ Staphylococcus aureus of colony forming unit (CFU), group B was inoculated with Staphylococcus aureus and PR-39. After operation, the wound conditions and histological changes were observed by X-ray and optical microscope respectively, CRP and erythrocyte sedimentation rate were measured by test assay.

RESULTS

The transfection efficiency of lentivirus vectortransfected BMSCs was 74.09%. The supernatant of lentivirus vector had obvious inhibitory effect on Staphylococcus aureus, and the antibacterial rate was 98.43%. 100% infection observed in group A while few infection observed in group B; serum CRP and ESR at a high level in group A while decreased in group B after operation. There were no significant difference in CRP and ESR between the pLV/PR-39 group and pLV/EGFP group at day 1 and 3 respectively after surgery. However, CRP and ESR in the pLV/PR-39 groupwere significantly lower than the pLV/EGFP group at day 7 and 14 respectively after operation.

CONCLUSIONS

Rabbits planted BMSCs expressing PR-39 were significantly increased resistance to Staphylococcus aureus in PJI than control group thus showing great potential for preventing implant-associated infection. It will provide a potential new therapeutic agent for implant-associated infection.

Cultivation and sequencing of rumen microbiome members from the Hungate1000 Collection

Rumen microbiome biology gets a boost with the release of 410 high-quality reference genomes from the Hungate1000 project.

Productivity of ruminant livestock depends on the rumen microbiota, which ferment indigestible plant polysaccharides into nutrients used for growth. Understanding the functions carried out by the rumen microbiota is important for reducing greenhouse gas production by ruminants and for developing biofuels from lignocellulose. We present 410 cultured bacteria and archaea, together with their reference genomes, representing every cultivated rumen-associated archaeal and bacterial family. We evaluate polysaccharide degradation, short-chain fatty acid production and methanogenesis pathways, and assign specific taxa to functions. A total of 336 organisms were present in available rumen metagenomic data sets, and 134 were present in human gut microbiome data sets. Comparison with the human microbiome revealed rumen-specific enrichment for genes encoding de novo synthesis of vitamin B₁₂, ongoing evolution by gene loss and potential vertical inheritance of the rumen microbiome based on underrepresentation of markers of environmental stress. We estimate that our Hungate genome resource represents ∼75% of the genus-level bacterial and archaeal taxa present in the rumen.

The challenges and importance of structural variation detection in livestock

Recent studies in humans and other model organisms have demonstrated that structural variants (SVs) comprise a substantial proportion of variation among individuals of each species. Many of these variants have been linked to debilitating diseases in humans, thereby cementing the importance of refining methods for their detection. Despite progress in the field, reliable detection of SVs still remains a problem even for human subjects. Many of the underlying problems that make SVs difficult to detect in humans are amplified in livestock species, whose lower quality genome assemblies and incomplete gene annotation can often give rise to false positive SV discoveries. Regardless of the challenges, SV detection is just as important for livestock researchers as it is for human researchers, given that several productive traits and diseases have been linked to copy number variations (CNVs) in cattle, sheep, and pig. Already, there is evidence that many beneficial SVs have been artificially selected in livestock such as a duplication of the agouti signaling protein gene that causes white coat color in sheep. In this review, we will list current SV and CNV discoveries in livestock and discuss the problems that hinder routine discovery and tracking of these polymorphisms. We will also discuss the impacts of selective breeding on CNV and SV frequencies and mention how SV genotyping could be used in the future to improve genetic selection.

Changes in milk protein composition during acute involution at different phases of tammar wallaby (Macropus eugenii) lactation

This study exploited the unusual lactation cycle of the tammar wallaby (Macropus eugenii) to characterise milk composition during acute involution, a time when the mammary gland is subjected to increased risk of infection. In early-lactation, tammar milk contains elevated levels of complex oligosaccharides and low protein and lipid content. Later in lactation, protein and lipid concentrations increase significantly, whereas carbohydrate content is reduced dramatically and changes to monosaccharides. Following initiation of involution at early-lactation, the carbohydrate concentration greatly decreased, while lipid and protein concentrations were elevated, suggesting that complex oligosaccharides are the major osmole in milk at this time. In contrast, involution at late lactation, when carbohydrate concentration was very low, led to an increase in the lipid concentration, but the concentration of protein was not significantly altered. This indicates that protein synthesis during acute involution at late lactation in the tammar may be down-regulated much more rapidly than during early-lactation. Analysis of milk at day 3 after the onset of involution at early-lactation identified a number of potential antimicrobials secreted at high concentrations, including lysozyme, dermcidin, polymeric immunoglobulin receptor and fragments of beta-lactoglobulin. These proteins may protect the mammary gland by minimising the risk of potential infection during involution.

Digestive function of lysozyme in synanthropic acaridid mites enables utilization of bacteria as a food source

The activity of lysozyme, the enzyme that hydrolyzes peptidoglycan in G(+) bacterial cell walls, was detected in whole mite extracts (WME) and in spent growth medium extracts (SGME) of 14 species of synanthropic mites (Acari: Acaridida). The adaptation of lysozyme for digestive activity and bacteriophagy was based on: (i) high lysozyme activity in SGME, and (ii) the correlation of maximum lysozyme activity at acidic pH values, corresponding to pH in the ventriculus and caeca. We show that the digestion of fluorescein-labeled Micrococcus lysodeikticus cells began in ventriculus and continued during the passage of a food bolus through the gut. The fluorescein was absorbed by midgut cells and penetrated to parenchymal tissues. Eight species showed a higher rate of population growth on a M. lysodeikticus diet than on a control diet. The lysozyme activity in SGME was positively correlated to the standardized rate (r (s)) of population growth, although no correlation was found between r (s) and lysozyme activity in WME. The lysozyme activity in WME was negatively correlated to that in SGME. The highest activity of digestive lysozyme was found in Lepidoglyphus destructor, Chortoglyphus arcuatus and Dermatophagoides farinae. All of these findings indicate that lysozyme in acaridid mites possesses both defensive and digestive functions. The enzymatic properties of mite lysozyme are similar to those of the lysozymes present in the ruminant stomach and in the insect midgut.

Stomach lysozymes of the three-toed sloth (Bradypus variegatus), an arboreal folivore from the Neotropics

Lysozymes are antimicrobial defences that act as digestive enzymes when expressed in the stomach of herbivores with pre-gastric fermentation. We studied this enzyme in the complex stomach of the three-toed sloth (Bradypus variegatus), a folivore with pre-gastric fermentation. Lysozymes were identified by SDS-PAGE and immunoblotting in all portions: diverticulum, pouch, glandular and muscular prepyloric area with 14.3 kDa of molecular mass. Purified lysozymes from all areas but the diverticulum were characterized by MALDI-TOF, optimal pH, optimal ionic strength, and specific activity. The differences observed suggested at least three isoforms. The optimal pHs were similar to the pH of the stomach portion where the enzymes were isolated. The lysozyme from the pouch (fermentation chamber) exhibited higher specific activity and concentration than the others. The specific activity of the enzyme from the acid muscular prepyloric portion was comparable to that reported in the cow abomasums; however, its concentration was lower than that observed in cow. This distinctive pattern of secretion/specific activity and overall low concentration suggests different roles for the lysozymes in this herbivore compared to Artiodactyla. We postulate that sloth stomach lysozymes may still be antimicrobial defences by protecting the microbial flora of the fermentation chamber against foreign bacteria.