Overexpression of PtVDL1 in Phaeodactylum tricornutum Increases Fucoxanthin Content under Red Light

Phaeodactylum tricornutum is a model diatom with significant biotechnological applications, including enhancing biomass, biofuel, and carotenoid production. Specifically, owing to the capacity of this organism to serve as a valuable source of essential raw materials for pharmaceuticals and nutraceuticals, ongoing research is actively focused on enhancing its productivity. One of the genes involved in various stages of fucoxanthin (Fx) biosynthesis, violaxanthin de-epoxidase like 1 (VDL1), has recently been identified. To validate the intracellular function of this gene and boost Fx production through overexpression, we established and examined three transgenic P. tricornutum lines characterized by elevated P. tricortunum VDL1 ( PtVDL1) expression and evaluate their cell growth and Fx productivity. These transgenic lines exhibited substantially increased PtVDL1 mRNA and protein levels compared to the wild type (WT). Notably, the enzyme substrate violaxanthin was entirely depleted and could not be detected in the transformants, whereas it remained at constant levels in the WT. Interestingly, under standard white light conditions, Fx productivity in the transformants remained unchanged; however, but after 48 h of exposure to red light, it increased by up to 15%. These results indicate that PtVDL1-overexpressing P. tricornutum has industrial potential, particularly for enhancing Fx production under red light conditions.

Improved Measurements of Muonic Helium Ground-State Hyperfine Structure at a Near-Zero Magnetic Field

Muonic helium atom hyperfine structure (HFS) measurements are a sensitive tool to test the three-body atomic system and bound-state quantum electrodynamics theory, and determine fundamental constants of the negative muon magnetic moment and mass. The world's most intense pulsed negative muon beam at the Muon Science Facility of the Japan Proton Accelerator Research Complex allows improvement of previous measurements and testing further CPT invariance by comparing the magnetic moments and masses of positive and negative muons (second-generation leptons). We report new ground-state HFS measurements of muonic helium-4 atoms at a near-zero magnetic field, performed for the first time using a small admixture of CH_{4} as an electron donor to form neutral muonic helium atoms efficiently. Our analysis gives Δν=4464.980(20)  MHz (4.5 ppm), which is more precise than both previous measurements at weak and high fields. The muonium ground-state HFS was also measured under the same conditions to investigate the isotopic effect on the frequency shift due to the gas density dependence in He with CH_{4} admixture and compared with previous studies. Muonium and muonic helium can be regarded as light and heavy hydrogen isotopes with an isotopic mass ratio of 36. No isotopic effect was observed within the current experimental precision.

FRET-based hACE2 receptor mimic peptide conjugated nanoprobe for simple detection of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has led to a pandemic of acute respiratory disease, namely coronavirus disease (COVID-19). This disease threatens human health and public safety. Early diagnosis, isolation, and prevention are important to suppress the outbreak of COVID 19 given the lack of specific antiviral drugs to treat this disease and the emergence of various variants of the virus that cause breakthrough infections even after vaccine administration. Simple and prompt testing is paramount to preventing further spread of the virus. However, current testing methods, namely RT-PCR, is time-consuming. Binding of the SARS-CoV-2 spike (S) glycoprotein to human angiotensin-converting enzyme 2 (hACE2) receptor plays a pivotal role in host cell entry. In the present study, we developed a hACE2 mimic peptide beacon (COVID19-PEB) for simple detection of SARS-CoV-2 using a fluorescence resonance energy transfer system. COVID19-PEB exhibits minimal fluorescence in its ''closed'' hairpin structure; however, in the presence of SARS-CoV-2, the specific recognition of the S protein receptor-binding domain by COVID19-PEB causes the beacon to assume an ''open'' structure that emits strong fluorescence. COVID19-PEB can detect SARS-CoV-2 within 3 h or even 50 min and exhibits strong fluorescence even at low viral concentrations, with a detection limit of 4 × 10³ plaque-forming unit/test. Furthermore, in SARS-CoV-2-infected patient samples confirmed using polymerase chain reaction, COVID19-PEB accurately detected the virus. COVID19-PEB could be developed as a rapid and accurate diagnostic tool for COVID-19.

Computational and Histological Analyses for Investigating Mechanical Interaction of Thermally Drawn Fiber Implants with Brain Tissue

The development of a compliant neural probe is necessary to achieve chronic implantation with minimal signal loss. Although fiber-based neural probes fabricated by the thermal drawing process have been proposed as a solution, their long-term effect on the brain has not been thoroughly investigated. Here, we examined the mechanical interaction of thermally drawn fiber implants with neural tissue through computational and histological analyses. Specifically, finite element analysis and immunohistochemistry were conducted to evaluate the biocompatibility of various fiber implants made with different base materials (steel, silica, polycarbonate, and hydrogel). Moreover, the effects of the coefficient of friction and geometric factors including aspect ratio and the shape of the cross-section on the strain were investigated with the finite element model. As a result, we observed that the fiber implants fabricated with extremely softer material such as hydrogel exhibited significantly lower strain distribution and elicited a reduced immune response. In addition, the implants with higher coefficient of friction (COF) and/or circular cross-sections showed a lower strain distribution and smaller critical volume. This work suggests the materials and design factors that need to be carefully considered to develop future fiber-based neural probes to minimize mechanical invasiveness.

Pre-Transplant Marital Status and Hematopoietic Cell Transplantation Outcomes

Background

Evidence about the impact of marital status before hematopoietic cell transplantation (hct) on outcomes after hct is conflicting.

Methods

We identified patients 40 years of age and older within the Center for International Blood and Marrow Transplant Research registry who underwent hct between January 2008 and December 2015. Marital status before hct was declared as one of: married or living with a partner, single (never married), separated or divorced, and widowed. We performed a multivariable analysis to determine the association of marital status with outcomes after hct.

Results

We identified 10,226 allogeneic and 5714 autologous hct cases with, respectively, a median follow-up of 37 months (range: 1-102 months) and 40 months (range: 1-106 months). No association between marital status and overall survival was observed in either the allogeneic (p = 0.58) or autologous (p = 0.17) setting. However, marital status was associated with grades 2-4 acute graft-versus-host disease (gvhd), p < 0.001, and chronic gvhd, p = 0.04. The risk of grades 2-4 acute gvhd was increased in separated compared with married patients [hazard ratio (hr): 1.13; 95% confidence interval (ci): 1.03 to 1.24], and single patients had a reduced risk of grades 2-4 acute gvhd (hr: 0.87; 95% ci: 0.77 to 0.98). The risk of chronic gvhd was lower in widowed compared with married patients (hr: 0.82; 95% ci: 0.67 to 0.99).

Conclusions

Overall survival after hct is not influenced by marital status, but associations were evident between marital status and grades 2-4 acute and chronic gvhd. To better appreciate the effects of marital status and social support, future research should consider using validated scales to measure social support and patient and caregiver reports of caregiver commitment, and to assess health-related quality of life together with health care utilization.

Enhanced pyruvate metabolism in plastids by overexpression of putative plastidial pyruvate transporter in Phaeodactylum tricornutum

BACKGROUND

The development of microalgal strains for enhanced biomass and biofuel production has received increased attention. Moreover, strain development via metabolic engineering for commercial production is being considered as the most efficient strategy. Pyruvate is an essential metabolite in the cells and plays an essential role in amino acid biosynthesis and de novo fatty acid biosynthesis in plastids. Although pyruvate can be a valuable target for metabolic engineering, its transporters have rarely been studied in microalgae. In this study, we aimed to identify the plastidial pyruvate transporter of Phaeodactylum tricornutum and utilize it for strain development.

RESULTS

We identified putative pyruvate transporter localized in the plastid membrane of Phaeodactylum tricornutum. Transformants overexpressing the pyruvate transporter were generated to increase the influx of pyruvate into plastids. Overexpression of a plastidial pyruvate transporter in P. tricornutum resulted in enhanced biomass (13.6% to 21.9%), lipid contents (11% to 30%), and growth (3.3% to 8.0%) compared to those of wild type during one-stage cultivation.

CONCLUSION

To regulate the pyruvate influx and its metabolism in plastids, we generated transformants overexpressing the putative plastidial pyruvate transporter in P. tricornutum. They showed that its overexpression for compartmentalizing pyruvate in plastids could be an attractive strategy for the effective production of biomass and lipids with better growth, via enhanced pyruvate metabolism in plastids.

Exogenous β-mannanase supplementation improved immunological and metabolic responses in lactating dairy cows

Exogenous enzymes have been used to improve nutrient utilization in several species of livestock, particularly swine and poultry. In addition, improved immunological and metabolic traits have been reported in nonruminants. The objective of this study was to determine the effects of β-mannanase supplementation on milk yield and composition, and immunological and metabolic responses in lactating Holstein dairy cows. Two weeks after calving, 20 Holstein cows (10 multiparous and 10 primiparous) were blocked by parity and assigned to 1 of 2 diets for 182 d. All cows were housed in the same environment and fed the same basal diet. The basal diet of the treatment group was supplemented with β-mannanase (CTCBio Inc., Seoul, South Korea) at 0.1% of concentrate dry matter. No differences were detected between the control and enzyme supplement groups in milk yield parameters or milk composition. Supplementation of β-mannanase enzyme reduced blood haptoglobin levels in supplemented multiparous cows compared with controls. Furthermore, nonesterified fatty acid concentration levels tended to be lower in cows fed β-mannanase, regardless of parity. Neither immunoglobulin G nor milk somatic cell count was affected by β-mannanase supplementation, regardless of parity. The number of insemination services tended to be lower in cows fed diets supplemented with β-mannanase. Results from this study suggest that supplementation of β-mannanase exogenous enzyme could help to reduce instances of systemic inflammation and decrease fat mobilization in lactating Holstein cows. Multiparous cows are considered susceptible to acute infections and inflammation; thus, the enzyme had a greater effect in multiparous cows.

New precise measurements of muonium hyperfine structure at J-PARC MUSE

High precision measurements of the ground state hyperfine structure (HFS) of muonium is a stringent tool for testing bound-state quantum electrodynamics (QED) theory, determining fundamental constants of the muon magnetic moment and mass, and searches for new physics. Muonium is the most suitable system to test QED because both theoretical and experimental values can be precisely determined. Previous measurements were performed decades ago at LAMPF with uncertainties mostly dominated by statistical errors. At the J-PARC Muon Science Facility (MUSE), the MuSEUM collaboration is planning complementary measurements of muonium HFS both at zero and high magnetic field. The new high-intensity muon beam that will soon be available at H-Line will provide an opportunity to improve the precision of these measurements by one order of magnitude. An overview of the different aspects of these new muonium HFS measurements, the current status of the preparation for high-field measurements, and the latest results at zero field are presented.

Usefulness of TSH receptor antibodies as biomarkers for Graves' ophthalmopathy: a systematic review

PURPOSE

Over the past several decades, many papers have been published about the usefulness of thyrotropin receptor antibodies (TRAbs) as biomarkers of Graves' ophthalmopathy (GO). However, results have been inconsistent. The purpose of this analysis is to determine a possible cause of these discrepancies and to examine the usefulness of TRAbs as biomarkers for GO, especially 'thyrotropin-binding inhibiting immunoglobulin (TBII)' and 'thyroid-stimulating antibody (TSAb)'.

METHOD

26 articles discussing the association between TRAbs and GO were selected which were then divided into three groups based on the study method and whether or not the patients had been treated for hyperthyroidism. From the results of the papers reviewed, a provisional conclusion was made and a theoretical model on the TBII-TSAb coordinate plane was developed to confirm that conclusion.

RESULTS

TSAb is reported to be significantly or strongly associated with GO in the studies of pre- and post-treated patients for hyperthyroidism. TBII is positively correlated, negatively correlated or uncorrelated with GO in studies of pre-treated patients. However, it is generally agreed upon that TBII and GO are closely correlated in studies of post-treated patients.

CONCLUSION

We conclude that the level of TBII may not be a reliable indicator of the current state of GO in pre-treated patients. Whereas, in post-treated patients, due to changes in the correlation between TBII and TSAb due to the effect of hyperthyroidism treatment, the level of TBII can be a more reliable indicator of GO. Furthermore, the current level of TBII is closely associated with the onset and severity of GO in the future and it can be a valid predictor of GO. However, the TSAb level appears to be more reliable.

Effectiveness of a multidisciplinary patient care bundle for reducing surgical-site infections

BACKGROUND

Surgical-site infection (SSI) is associated with significant healthcare costs. To reduce the high rate of SSI among patients undergoing colorectal surgery at a cancer centre, a comprehensive care bundle was implemented and its efficacy tested.

METHODS

A pragmatic study involving three phases (baseline, implementation and sustainability) was conducted on patients treated consecutively between 2013 and 2016. The intervention included 13 components related to: bowel preparation; oral and intravenous antibiotic selection and administration; skin preparation, disinfection and hygiene; maintenance of normothermia during surgery; and use of clean instruments for closure. SSI risk was evaluated by means of a preoperative calculator, and effectiveness was assessed using interrupted time-series regression.

RESULTS

In a population with a mean BMI of 30 kg/m² , diabetes mellitus in 17·5 per cent, and smoking history in 49·3 per cent, SSI rates declined from 11·0 to 4·1 per cent following implementation of the intervention bundle (P = 0·001). The greatest reductions in SSI rates occurred in patients at intermediate or high risk of SSI: from 10·3 to 4·7 per cent (P = 0·006) and from 19 to 2 per cent (P < 0·001) respectively. Wound care modifications were very different in the implementation phase (43·2 versus 24·9 per cent baseline), including use of an overlying surface vacuum dressing (17·2 from 1·4 per cent baseline) or leaving wounds partially open (13·2 from 6·7 per cent baseline). As a result, the biggest difference was in wound-related rather than organ-space SSI. The median length of hospital stay decreased from 7 (i.q.r. 5-10) to 6 (5-9) days (P = 0·002). The greatest reduction in hospital stay was seen in patients at high risk of SSI: from 8 to 6 days (P < 0·001). SSI rates remained low (4·5 per cent) in the sustainability phase.

CONCLUSION

Meaningful reductions in SSI can be achieved by implementing a multidisciplinary care bundle at a hospital-wide level.

Abstract PD2-07: Real-time navigation for sentinel lymph node biopsy in breast cancer patients using projection mapping with indocyanine green fluorescence

Background)

Sentinel lymph node (SLN) biopsy using indocyanine green fluorescence (fICG) method showed equal or better identification rate compared with blue dye or radioisotope (RI) method. In the fICG method, lymphatic vessels which drain into the SLNs can be seen through skin or subcutaneous tissue using near infrared camera (Photodynamic Eye®: PDE), and we can easily find the SLNs. However, whenever we observe the fluorescence images, we have to hold the PDE, turn off the operating light, and look at a monitor because fluorescence images cannot be seen directly. Medical imaging projection system (MIPS) is a new device which detects fluorescent emission from the organ and projects their images on the location of the fluorescence emission (Panasonic Connected Solutions Company, Japan). Projected images can be adjusted following the body movement or deformation of the organ. Therefore, MIPS could provide an option for real-time navigation for the SLN biopsy. The aim of this study was to evaluate the clinical utility of the MIPS.

Patients and methods)

Patients with clinically node-negative primary breast cancer underwent the fICG SLN biopsy using MIPS. Primary endpoint was identification rate of the fICG method using MIPS. At first, the study was conducted as an interventional study because the MIPS was the unapproved medical device. After approval of the MIPS, this study was conducted as an observational study. The study protocol was approved by the institutional review board at Kyoto University Hospital. All patients provided informed consent to participate in this study.

Results)

Between March 2016 and May 2017, 39 patients (40 procedures) underwent the fICG method SLN biopsy using MIPS. The median age was 55 years (range 32–74 years), and the median body mass index was 20.4 kg/m2 (range 17.7–27.7 kg/m2). About half had tumor stage T1 (58%) and 8 (20.0%) had DCIS. 8 procedures (20%) were performed after preoperative systemic therapy (PST). As MIPS itself can illuminate the operating field, SLN biopsy using MIPS was successfully performed without operating light in all procedures. At least one SLN was detected using MIPS for all procedures and the identification rate was 100% (95% CI: 91–100%). Median number of SLNs detected by MIPS was 3 (range 1–9) for all procedures, and 3 (range 2–8) for procedures after PST. Two pathologically positive SLNs and one SLN which included isolated tumor cells were detected by MIPS. In 25 procedures, RI was also used. 62 of 97 SLNs detected by MIPS (64%) were also detected by RI. However, no SLNs were detected only by RI.

Conclusions)

Although we still may not be able to avoid RI method because 25/40 (62.5%) procedures required the combined use of RI method, the fICG methods SLN biopsy using MIPS, which showed comparable identification rate of SLN with the conventional methods, could be useful tool with a view of allowing us to perform a real-time navigation surgery.

Acknowledgements)

This study was supported by Acceleration Transformative research for Medical innovation, Japan Agency for Medical Research and Development (AMED).

Citation Format: Takada M, Takeuchi M, Suzuki E, Sato F, Matsumoto Y, Torii M, Sakita-Kawaguchi N, Nakayama Y, Okuda T, Nishino H, Seo S, Hatano E, Toi M. Real-time navigation for sentinel lymph node biopsy in breast cancer patients using projection mapping with indocyanine green fluorescence [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD2-07.

Differential protein stability and clinical responses of EML4-ALK fusion variants to various ALK inhibitors in advanced ALK-rearranged non-small cell lung cancer

Background

Anaplastic lymphoma kinase (ALK) inhibition using crizotinib has become the standard of care in advanced ALK-rearranged non-small cell lung cancer (NSCLC), but the treatment outcomes and duration of response vary widely. Echinoderm microtubule-associated protein-like 4 (EML4)-ALK is the most common translocation, and the fusion variants show different sensitivity to crizotinib in vitro. However, there are only limited data on the specific EML4-ALK variants and clinical responses of patients to various ALK inhibitors.

Patients and methods

By multiplex reverse-transcriptase PCR, which detects 12 variants of known EML4-ALK rearrangements, we retrospectively determined ALK fusion variants in 54 advanced ALK rearrangement-positive NSCLCs. We subdivided the patients into two groups (variants 1/2/others and variants 3a/b) by protein stability and evaluated correlations of the variant status with clinical responses to crizotinib, alectinib, or ceritinib. Moreover, we established the EML4-ALK variant-expressing system and analyzed patterns of sensitivity of the variants to ALK inhibitors.

Results

Of the 54 tumors analyzed, EML4-ALK variants 3a/b (44.4%) was the most common type, followed by variants 1 (33.3%) and 2 (11.1%). The 2-year progression-free survival (PFS) rate was 76.0% [95% confidence interval (CI) 56.8-100] in group EML4-ALK variants 1/2/others versus 26.4% (95% CI 10.5-66.6) in group variants 3a/b (P = 0.034) among crizotinib-treated patients. Meanwhile, the 2-year PFS rate was 69.0% (95% CI 49.9-95.4) in group variants 1/2/others versus 32.7% (95% CI 15.6-68.4) in group variants 3a/b (P = 0.108) among all crizotinib-, alectinib-, and ceritinib-treated patients. Variant 3a- or 5a-harboring cells were resistant to ALK inhibitors with >10-fold higher half maximal inhibitory concentration in vitro.

Conclusion

Our findings show that group EML4-ALK variants 3a/b may be a major source of ALK inhibitor resistance in the clinic. The variant-specific genotype of the EML4-ALK fusion allows for more precise stratification of patients with advanced NSCLC.

Effects of Smartphone-based Memory Training for Older Adults with Subjective Memory Complaints

Introduction

Brain health has garnered increasing attention as a requisite condition for healthy aging. The rapid growth in mobile health and increasing smartphone ownership among older adults has paved the way for smartphones to be utilized as effective tools for improving mental fitness.

Objectives

There are few studies that have explored the efficacy of smartphone-based cognitive training. The present study examined the memory-enhancing effects of smartphone-based memory training for older adults.

Aims

We explored whether newly developed application “Smartphone-based brain Anti-aging and memory Reinforcement Training (SMART)” improved memory performance in older adults with subjective memory complaints.

Methods

A total of 53 adults (mean age: 59.3 years) were randomised into either one of two smartphone-based intervention groups (SMART vs. Fit Brains®) or a wait-list group. Participants in the intervention groups underwent 15–20 minutes of training per day, five days per week for 8 weeks. We used objective cognitive measures to evaluate changes with respect to four domains: attention, memory, working memory (WM), and executive function (inhibition, fluency, etc.). In addition, we included self-report questionnaires to assess levels of subjective memory complaints.

Results

The performance on WM test increased significantly in the SMART group (t[17] = 6.27, P < 0.0001) but not in the control groups. Self-reports of memory contentment, however, increased in the Fit Brains® group only (t[18] = 2.12, P = 0.048).

Conclusions

Use of an 8-week smartphone-based memory training program may improve working memory function in older adults. However, objective improvement in performance does not necessarily lead to decreased subjective memory complaints.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Label-free cell-substrate adhesion imaging on plasmonic nanocup arrays

Cell adhesion is a crucial biological and biomedical parameter defining cell differentiation, cell migration, cell survival, and state of disease. Because of its importance in cellular function, several tools have been developed in order to monitor cell adhesion in response to various biochemical and mechanical cues. However, there remains a need to monitor cell adhesion and cell-substrate separation with a method that allows real-time measurements on accessible equipment. In this article, we present a method to monitor cell-substrate separation at the single cell level using a plasmonic extraordinary optical transmission substrate, which has a high sensitivity to refractive index changes at the metal-dielectric interface. We show how refractive index changes can be detected using intensity peaks in color channel histograms from RGB images taken of the device surface with a brightfield microscope. This allows mapping of the nonuniform refractive index pattern of a single cell cultured on the plasmonic substrate and therefore high-throughput detection of cell-substrate adhesion with observations in real time.

GvHD after umbilical cord blood transplantation for acute leukemia: an analysis of risk factors and effect on outcomes

Using the Center for International Blood and Marrow Transplant Research (CIBMTR) registry, we analyzed 1,404 UCBT patients [single (< 18 years) = 810, double (≥ 18 years) = 594] with acute leukemia to define the incidence of acute and chronic graft-vs.-host disease (GVHD), analyze clinical risk factors and investigate outcomes. After single UCBT, 100-day incidence of grades II–IV aGVHD was 39% (95% CI, 36–43%), grades III–IV aGVHD was 18% (95% CI, 15–20%), and 1-year cGVHD was 27% (95% CI, 24–30%). After double UCBT, 100-day incidence of grades II–IV aGVHD was 45% (95% CI, 41%–49%), grades III–IV aGVHD was 22% (95% CI, 19–26%), and 1-year cGVHD was 26% (95% CI, 22–29%). For single UCBT, multivariate analysis showed that absence of anti-thymocyte globulin (ATG) was associated with aGVHD, whereas prior aGVHD was associated with cGVHD. For double UCBT, absence of ATG and myeloablative conditioning were associated with aGVHD, while prior aGVHD predicted for cGVHD. Grades III–IV aGVHD led to worse survival whereas cGVHD had no significant effect on disease-free or overall survival. GVHD is prevalent after UCBT with severe aGVHD leading to higher mortality. Future research in UCBT should prioritize prevention of GVHD.

Exogenous β-mannanase improves feed conversion efficiency and reduces somatic cell count in dairy cattle

Exogenous fibrolytic enzymes have been shown to be a promising way to improve feed conversion efficiency (FCE). β-Mannanase is an important enzyme digesting the polysaccharide β-mannan in hemicellulose. Supplementation of diets with β-mannanase to improve FCE has been more extensively studied in nonruminants than in ruminants. The objective of this study was to investigate the effects of β-mannanase supplementation on nutrient digestibility, FCE, and nitrogen utilization in lactating Holstein dairy cows. Twelve post-peak-lactation multiparous Holstein cows producing 45.5±6.6kg/d of milk at 116±19.0d in milk were randomly allotted to 1 of 3 treatments in a 3×3 Latin square design with 3 periods of 18d (15d for adaptation plus 3d for sample collection). All cows were fed the same basal diet and the 3 treatments differed only by the β-mannanase dose: 0% dry matter (DM; control), 0.1% of DM (low supplement, LS), and 0.2% of DM (high supplement, HS) supplemented to the basal diet. Supplementation of β-mannanase enzyme at the LS dose reduced dry matter intake (DMI) but did not affect milk yield or milk composition. Cows receiving LS produced 90g more milk per kg of DMI compared with control cows. Somatic cell count (SCC) in milk was lower for cows fed the LS diet compared with cows fed control diets. Cows fed LS diet had lower DM, organic matter and crude protein digestibility compared with cows fed control diets. Starch, neutral detergent fiber, and acid detergent fiber digestibility were not affected by LS. Milk yield, DMI, SCC, and nutrient digestibility did not change for HS. Despite the reduced crude protein digestibility, reduced N intake led to similar fecal N excretions in LS cows and control cows (234 vs. 235g/cow per day). Urinary N excretions remained similar between enzyme-fed and control cows (~190g/cow per day), although the percentage of N intake partitioned to urinary N tended to be greater in LS than in control cows (31 vs. 27%). Cows fed LS significantly improved the percentage of apparently absorbed N partitioned to milk protein N (42 vs. 38%). When supplemented at 0.1% of dietary DM, β-mannanase can improve FCE and lower the SCC of dairy cows without affecting milk yield, milk composition, or total manure N excretions of dairy cows.