Effects of increasing dietary zinc sulfate fed to gestating ewes: II. Milk somatic cell count, microbial populations, and fatty acid composition

Objective: The objective of the research was to evaluate the effects of increasing dietary Zn sulfate concentration for primiparous gestating ewes on subsequent milk SCC, intramammary microbial identifications, and fatty acid composition. Materials and Methods: Commercial white-face (WF; n = 27) and black-face (BF; n = 24) ewes (age ≈18 mo; BW = 87.48 ± 8.37 kg) were sorted into breed-type groups and within groups ranked by BW, and then, they were randomly divided into 3 dietary supplement treatment groups: CON (n = 13; 40 mg/kg Zn; ≈1 × NASEM recommendations), Zn500 (n = 21; 500 mg/kg Zn; ≈4 × NASEM recommendations), and Zn1000 (n = 17; 1,000 mg/kg Zn; ≈7 × NASEM recommendations). Treatments were administered in Zn-fortified pelleted alfalfa (0.45 kg/ewe per day) and fed from 87.5 ± 8.9 d of gestation until parturition. Milk traits collected at parturition (d 1 of lactation), ≈30 d of lactation, and lamb weaning (≈90 d of lactation) were assessed as repeated measures with fixed effects of treatment, breed type, and litter size. Results and Discussion: The treatment × breed type interaction affected ewe logSCC (P = 0.01), and within Zn500, BF had greater logSCC than WF ewes (5.90 ± 0.08 vs. 5.46 ± 0.08; P \u3c 0.01). However, breed types did not differ between CON and Zn1000 treatments (P ≥ 0.92). Ewe logSCC was greatest (P \u3c 0.01) at weaning (6.03 ± 0.06), intermediate at parturition (5.72 ± 0.06; d 1), and least at d 30 of lactation (5.21 ± 0.06). Intramammary infections were common in milk samples collected at parturition (77%) and weaning (47%) based on culture-based microbial identifications. The most frequently identified species included Bacillus spp. and Staphylococcus spp. Black-face ewes had greater concentrations of C16:1 (1.78 mg/100 vs. 1.39 mg/100 mg of fatty acid per 100 mg of total fatty acids), C17:1 (0.86 mg/100 vs. 0.76 mg/100 mg of fatty acid per 100 mg of total fatty acids), and C20:4 (0.28 mg/100 vs. 0.24 mg/100 mg of fatty acid per 100 mg of total fatty acids; P ≤ 0.04) than WF ewes. Implications and Applications: Including Zn in diets beyond NASEM recommendations from mid to late gestation had no effect on ewe milk SCC, microbial pathogens identified, or fatty acid composition. However, findings indicated there may be important breed differences in dietary Zn utilization and requirements affecting intramammary inflammation

Relationships among intramammary health, udder and teat characteristics, and productivity of extensively managed ewes

Mastitis is an economically important disease and its subclinical state is difficult to diagnose, which makes mitigation more challenging. The objectives of this study were to screen clinically healthy ewes in order to 1) identify cultivable microbial species in milk, 2) evaluate somatic cell count (SCC) thresholds associated with intramammary infection, and 3) estimate relationships between udder and teat morphometric traits, SCC, and ewe productivity. Milk was collected from two flocks in early (\u3c5 \u3ed) and peak (30 to 45 d) lactation to quantify SCC (n = 530) and numerate cultivable microbial species by culture-based isolation followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS; n = 243) identification. Within flock and lactation stage, 11% to 74% (mean = 36%) of samples were culture positive. More than 50 unique identifications were classified by MALDI-TOF MS analysis, and Bacillus licheniformis (18% to 27%), Micrococcus flavus (25%), Bacillus amyloliquefaciens (7% to 18%), and Staphylococcus epidermidis (26%) were among the most common within flock and across lactation stage. Optimum SCC thresholds to identify culture-positive samples ranged from 175 × 103 to 1,675 × 103 cells/mL. Ewe productivity was assessed as total 120-d adjusted litter weight (LW120) and analyzed within flock with breed, parity, year, and the linear covariate of log10 SCC (LSCC) at early or peak lactation. Although dependent on lactation stage and year, each 1-unit increase in LSCC (e.g., an increase in SCC from 100 × 103 to 1,000 × 103 cells/mL) was predicted to decrease LW120 between 9.5 and 16.1 kg when significant. Udder and teat traits included udder circumference, teat length, teat placement, and degree of separation of the udder halves. Correlations between traits were generally low to moderate within and across lactation stage and most were not consistently predictive of ewe LSCC. Overall, the frequencies of bacteria-positive milk samples indicated that subclinical mastitis (SCM) is common in these flocks and can impact ewe productivity. Therefore, future research is warranted to investigate pathways and timing of microbial invasion, genomic regions associated with susceptibility, and husbandry to mitigate the impact of SCM in extensively managed ewes

Validation of a screening method for the detection of colistin-resistant \u3ci\u3eE. coli\u3c/i\u3e containing mcr-1 in feral swine feces

A method was developed and validated for the detection of colistin-resistant Escherichia coli containing mcr-1 in the feces of feral swine. Following optimization of an enrichment method using EC broth supplemented with colistin (1 μg/mL) and vancomycin (8 μg/mL), aliquots derived from 100 feral swine fecal samples were spiked with of one of five different mcr-1 positive E. coli strains (between 100 and 104 CFU/g), for a total of 1110 samples tested. Enrichments were then screened using a simple boil-prep and a previously developed real-time PCR assay for mcr-1 detection. The sensitivity of the method was determined in swine feces, with mcr-1 E. coli inocula of 0.1–9.99 CFU/g (n=340), 10–49.99 CFU/g (n=170), 50–99 CFU/g (n=255), 100–149 CFU/g (n=60), and 200–2200 CFU/g (n=175), which were detected with 32%, 72%, 88%, 95%, and 98% accuracy, respectively. Uninoculated controls (n = 100) were negative for mcr-1 following enrichment

Detection of Viruses from Bioaerosols Using Anion Exchange Resin

This protocol demonstrates a customized bioaerosol sampling method for viruses. In this system, anion exchange resin is coupled with liquid impingement-based air sampling devices for efficacious concentration of negatively-charged viruses from bioaerosols. Thus, the resin serves as an additional concentration step in the bioaerosol sampling workflow. Nucleic acid extraction of the viral particles is then performed directly from the anion exchange resin, with the resulting sample suitable for molecular analyses. Further, this protocol describes a custom-built bioaerosol chamber capable of generating virus-laden bioaerosols under a variety of environmental conditions and allowing for continuous monitoring of environmental variables such as temperature, humidity, wind speed, and aerosol mass concentration. The main advantage of using this protocol is increased sensitivity of viral detection, as assessed via direct comparison to an unmodified conventional liquid impinger. Other advantages include the potential to concentrate diverse negatively-charged viruses, the low cost of anion exchange resin (~$0.14 per sample), and ease of use. Disadvantages include the inability of this protocol to assess infectivity of resin-adsorbed viral particles, and potentially the need for the optimization of the liquid sampling buffer used within the impinger

Practicing Imperfect Forgiveness

Forgiveness is typically regarded as a good thing - even a virtue - but acts of forgiveness can vary widely in value, depending on their context and motivation. Faced with this variation, philosophers have tended to reinforce everyday concepts of forgiveness with strict sets of conditions, creating ideals or paradigms of forgiveness. These are meant to distinguish good or praiseworthy instances of forgiveness from problematic instances and, in particular, to protect the self-respect of would-be forgivers. But paradigmatic forgiveness is problematic for a number of reasons, including its inattention to forgiveness as a gendered trait. We can account for the values and the risks associated with forgiving far better if we treat it as a moral practice and not an ideal

A candidate ion-retaining state in the inward-facing conformation of sodium/galactose symporter: Clues from atomistic simulations

The recent Vibrio parahaemolyticus sodium/galactose (vSGLT) symporter crystal structure captures the protein in an inward-facing substrate-bound conformation, with the sodium ion placed, by structural alignment, in a site equivalent to the Na2 site of the leucine transporter (LeuT). A recent study, based on molecular dynamics simulations, showed that the sodium ion spontaneously leaves its initial position diffusing outside vSGLT, toward the intracellular space. This suggested that the crystal structure corresponds to an ion-releasing state of the transporter. Here, using metadynamics, we identified a more stable Na+ binding site corresponding to a putative ion-retaining state of the transporter. In addition, our simulations, consistently with mutagenesis studies, highlight the importance of D189 that, without being one of the NA(+)-coordinating residues, regulates its binding/release

Evaluation of fluorescence in situ hybridisation (FISH) for the detection of fungi directly from blood cultures and cerebrospinal fluid from patients with suspected invasive mycoses

The aim of this study was to evaluate the diagnostic performance of in-house FISH (fluorescence in situ hybridisation) procedures for the direct identification of invasive fungal infections in blood cultures and cerebrospinal fluid (CSF) samples and to compare these FISH results with those obtained using traditional microbiological techniques and PCR targeting of the ITS1 region of the rRNA gene. In total, 112 CSF samples and 30 positive blood cultures were investigated by microscopic examination, culture, PCR-RFLP and FISH. The sensitivity of FISH for fungal infections in CSF proved to be slightly better than that of conventional microscopy (India ink) under the experimental conditions, detecting 48 (instead of 46) infections in 112 samples. The discriminatory powers of traditional microbiology, PCR-RFLP and FISH for fungal bloodstream infections were equivalent, with the detection of 14 fungal infections in 30 samples. However, the mean times to diagnosis after the detection of microbial growth by automated blood culture systems were 5 hours, 20 hours and 6 days for FISH, PCR-RFLP and traditional microbiology, respectively. The results demonstrate that FISH is a valuable tool for the identification of invasive mycoses that can be implemented in the diagnostic routine of hospital laboratories. © 2015 Da Silva et al