Effects of direct-fed microbial supplement on ruminal and plasma metabolome of early-lactation dairy cows: Untargeted metabolomics approach

We examined the effects of 2 multispecies direct-fed microbial (DFM) supplements on ruminal and plasma metabolome of early-lactation dairy cows using a high-coverage untargeted metabolomics approach. A total of 45 multiparous Holstein cows (41 ± 7 DIM) were enrolled for the 14-d pre-experimental and 91-d experimental period and were a subset from a lactation performance study, which used 114 cows. Cows were blocked using pre-experimental energy-corrected milk yield and randomly assigned within each block to 1 of 3 treatments: (1) corn silage-based diet with no DFM supplement (control; CON), (2) basal diet top-dressed with a mixture of Lactobacillus animalis and Propionibacterium freudenreichii at 3 × 109 cfu/d (PRO-A), or (3) basal diet top-dressed with a mixture of L. animalis, P. freudenreichii, Bacillus subtilis, and Bacillus licheniformis at 11.8 × 109 cfu/d (PRO-B). The basal diet was fed ad libitum daily as a TMR at 0600 and 1200 h for a duration of 91 d. Rumen fluid and blood samples were taken on d -3, 28, 49, 70, and 91 and immediately stored at -80°C. Before analysis, ruminal and plasma samples from d 28, 49, 70, and 91 were composited. An in-depth, untargeted metabolome profile of the composite rumen and plasma samples and the d -3 samples was developed by using a chemical isotope labeling/liquid chromatography-mass spectrometry (LC-MS)-based technique. Differentially abundant metabolites (taking into account fold change [FC] values and false discovery rates [FDR]) were identified with a volcano plot. In the rumen, compared with the CON diet, supplemental PRO-A increased (FC ≥1.2; FDR ≤0.05) the relative concentrations of 9 metabolites, including 2-hydroxy-2,4-pentadienoic acid, glutaric acid, quinolinic acid, and shikimic acid, and PRO-B increased relative concentrations of 16 metabolites, including 2-hydroxy-2,4-pentadienoic acid, glutaric acid, 16-hydroxypalmitic acid, and 2 propionate precursors (succinic and methylsuccinic acids). Relative to PRO-A, supplemental PRO-B increased (FC ≥1.2; FDR ≤0.05) relative rumen concentrations of 3 metabolites, 16-hydroxypalmitic acid, indole-3-carboxylic acid, and 5-aminopentanoic acid, but reduced relative rumen concentrations of 13 metabolites, including carnitine, threonic acid, and shikimic acid. Compared with the CON diet, relative concentrations of 13 plasma metabolites, including myxochelin A and glyceraldehyde, were increased (FC ≥1.2; FDR ≤0.05) by PRO-A supplementation, whereas those of 9 plasma metabolites, including 4-(2-aminophenyl)-2,4-dioxobutanoic acid, N-acetylornithine, and S-norlaudanosolin, were reduced (FC ≤0.83; FDR ≤0.05). Supplemental PRO-B increased (FC ≥1.2; FDR ≤0.05) relative concentrations of 9 plasma metabolites, including trans-o-hydroxybenzylidenepyruvic acid and 3-methylsalicylaldehyde, and reduced relative concentrations of 4 plasma metabolites, including β-ethynylserine and kynurenine. Pathway analysis of the differentially abundant metabolites in both rumen and plasma revealed that these metabolites are involved in AA and fatty acid metabolism and have antimicrobial and immune-stimulating properties. The results of this study demonstrated that dietary supplementation with either PRO-A or PRO-B altered the plasma and ruminal metabolome. Notably, ruminal and plasma metabolites involved in the metabolism of AA and fatty acids and those with immunomodulatory properties were altered by either or both of the 2 microbial additives.

Effects of direct-fed microbial supplementation on performance and immune parameters of lactating dairy cows

We evaluated the effects of supplementing bacterial direct-fed microbial (DFM) on performance, apparent total-tract digestibility, rumen fermentation, and immune parameters of lactating dairy cows. One hundred fourteen multiparous Holstein cows (41 ± 7 DIM) were used in a randomized complete block design with an experiment comprising 14 d of a covariate (pre-experimental sample and data collection) and 91 d of an experimental period. Cows were blocked based on energy-corrected milk (ECM) yield during the covariate period and the following treatments were randomly assigned within each block: (1) control (CON), corn silage-based total mixed ration without DFM; (2) PRO-A, basal diet top-dressed with a mixture of Lactobacillus animalis and Propionibacterium freudenreichii at 3 × 109 cfu/d; and 3) PRO-B, basal diet top-dressed with a mixture of L. animalis, P. freudenreichii, Bacillus subtilis, and Bacillus licheniformis at 11.8 × 109 cfu/d. Milk yield, dry matter intake (DMI), and body weight were measured daily, while milk samples for component analysis were taken on 2 consecutive days of each week of data collection. Feces, urine, rumen, and blood samples were taken during the covariate period, wk 4, 7, 10, and 13 for estimation of digestibility, N-partitioning, rumen fermentation, plasma nutrient status and immune parameters. Treatments had no effect on DMI and milk yield. Fat-corrected milk (3.5% FCM) and milk fat yield were improved with PRO-B, while milk fat percent and feed efficiency (ECM/DMI) tended to increase with PRO-B compared with PRO-A and CON. Crude fat digestibility was greater with PRO-B compared with CON. Feeding CON and PRO-A resulted in higher total volatile fatty acid concentration relative to PRO-B. Percentage of neutrophils tended to be reduced with PRO-A compared with CON and PRO-B. The mean fluorescence intensity (MFI) of anti-CD44 antibody on granulocytes tended to be higher in PRO-B compared with CON. The MFI of anti-CD62L antibody on CD8+ T cells was lower in PRO-A than PRO-B, with PRO-A also showing a tendency to be lower than CON. This study indicates the potential of DFM to improve fat digestibility with consequential improvement in fat corrected milk yield, feed efficiency and milk fat yield by lactating dairy cows. The study findings also indicate that dietary supplementation with DFM may augment immune parameters or activation of immune cells, including granulocytes and T cells; however, the overall effects on immune parameters are inconclusive.

Pandemic Influenza A (H1N1): knowledge among senior health workers at a secondary health care institution in Southwest, Nigeria

OBJECTIVE

This study was conducted to assess the level of knowledge of influenza A (H1N1) infection among health care workers in a secondary health care facility in Osogbo, Southwest Nigeria.

METHODS

A structured questionnaire assessing participants'knowledge of swine influenza viruses, mode of transmission, clinical criteria, primary prevention, indications for emergency care, care of affected persons and ongoing pandemic of Influenza A H1N1 was hand-delivered to all senior health care workers working in the hospital.

RESULTS

The mean age of the respondents was 40.4±9.6 years. The majority (59.3%) were females. Television (73.6%) radio (61.5%), newspapers (44%), other health workers (31.9%), and internet (15.4%) were the main sources of information about influenza A H1N1. Nearly all (92.3%) felt that their source of information about the disease was inadequate. About half (51.6%) knew the virus can be transmitted from one person to another. Majority identified correctly the symptoms of infected victims such as fever (83.5%), and runny nose (79.1%). Most (87.9%) identified hand washing with soap and water as a mode of preventing transmission. Most (83.5%) felt an infected person should be isolated while very few knew oseltamivir (13.2%) and zanamivir (17.6%) are drugs to treat. Multivariate linear regression analysis identified, male sex (p=0.029), internet as a source of information (p=0.029) and knowledge of prevention of H1N1 (p= 0.005) as factors that were significantly associated with a high knowledge score on the current pandemic.

CONCLUSION

There is a need to provide comprehensive information to health workers on the current pandemic.