Improving influenza and pneumococcal vaccination uptake among incident peritoneal dialysis patients: a quality improvement initiative

INTRODUCTION

Influenza and pneumococcal vaccination rates among peritoneal dialysis (PD) patients remain suboptimal, despite availability of vaccinations and health recommendations.

AIM

The primary aim was to improve influenza and pneumococcal vaccination rates among incident PD patients at our center to 80%. A secondary aim was to develop a sustainable workflow for vaccination in PD patients.

DESIGN

A quality improvement (QI) initiative to increase vaccination rate among incident PD patients was conducted in a tertiary care hospital in Singapore from Jul 2017 to Dec 2018. Key drivers and barriers to success were identified through root cause analysis. Change ideas focusing on improving opportunities, access and enhancement of reminder systems were implemented using Plan-Do-Study-Act methodology. Vaccination rates were monitored at 3-month intervals.

RESULTS

Total of 249 patients were eligible for vaccination. The baseline vaccination rate for influenza, pneumococcal conjugate vaccine (PCV13) and pneumococcal polysaccharide vaccine (PPSV23) were 63%, 54% and 14%, respectively. Root-cause analyses revealed several practice-related barriers, including lack of physician recommendation, time constraints and ineffective reminder systems. Multifaceted interventions, such as the provision of vaccination at non-traditional clinical settings, physician audit and feedback, utilisation of reminder tools, successfully increased influenza, PCV13 and PPSV23 vaccination rates to 86%, 85% and 63%, respectively.

CONCLUSION

A robust influenza and pneumococcal vaccination program implemented using a standardized QI methodology and multidisciplinary approach is effective in improving and sustaining influenza and pneumococcal vaccination uptake among PD patients.

Understanding the dynamics of COVID-19; implications for therapeutic intervention, vaccine development and movement control

The COVID-19 disease is caused by the SARS-CoV-2 virus, which is highly infective within the human population. The virus is widely disseminated to almost every continent with over twenty-seven million infections and over ninety-thousand reported deaths attributed to COVID-19 disease. SARS-CoV-2 is a single stranded RNA virus, comprising three main viral proteins; membrane, spike and envelope. The clinical features of COVID-19 disease can be classified according to different degrees of severity, with some patients progressing to acute respiratory distress syndrome, which can be fatal. In addition, many infections are asymptomatic or only cause mild symptoms. As there is no specific treatment for COVID-19 there is considerable endeavour to raise a vaccine against SARS-CoV-2, in addition to engineering neutralizing antibody interventions. In the absence of an effective vaccine, movement controls of varying stringencies have been imposed. Whilst enforced lockdown measures have been effective, they may be less effective against the current strain of SARS-CoV-2, the G614 clade. Conversely, other mutations of the virus, such as the Δ382 variant could reduce the clinical relevance of infection. The front runners in the race to develop an effective vaccine focus on the SARS-Co-V-2 Spike protein. However, vaccines that produce a T-cell response to a wider range of SARS-Co-V-2 viral proteins, may be more effective. Population based studies that determine the level of innate immunity to SARS-CoV-2, from prior exposure to the virus or to other coronaviruses, will have important implications for government imposed movement control and the strategic delivery of vaccination programmes.

Sensitivity of in vitro digestible energy determined with computer-controlled simulated digestion system and its accuracy to predict dietary metabolizable energy for roosters

Two experiments were conducted to validate the sensitivity and accuracy of in vitro digestible energy (IVDE) determined with a computer-controlled simulated digestion system (CCSDS) to predict metabolizable energy (ME) of diets for roosters. In experiment 1, soybean hulls were added to a basal diet (calibration diet 1) at 2.06, 4.12, 6.17, 8.23, 10.28, 12.32, or 14.37% of the diets (calibration diets 2–8) to produce an interval of approximately 80 kcal ME/kg. The sensitivity was measured by comparing the determined and actual IVDE of the diets. With these data, a linear model was developed to predict ME from IVDE. In experiment 2, validation diets were identical except they were composed of different cereal ingredients. For each diet, the correlations and ratios between IVDE and ME were analyzed to test the sensitivity of IVDE to predict ME across different ingredients. In experiment 1, a slope of 0.9899 was calculated in a linear regression of determined IVDE on actual IVDE (R² = 0.9998; P < 0.01). The ratio of determined IVDE to actual IVDE was 0.9878. The ratio of IVDE to apparent metabolizable energy (AME) and to nitrogen-corrected AME (AMEn) was 1.03 and 1.05, respectively. The linear models to predict ME from IVDE were AME = 0.8449 × IVDE + 451 (R² = 0.9812, residual standard deviation [RSD] = 28 kcal/kg; P < 0.01) and AMEn = 0.8357 × IVDE + 436 (R² = 0.9821, RSD = 27 kcal/kg; P < 0.01). In experiment 2, a significant simple correlation was observed between the IVDE and AME or AMEn of validation diets (r > 0.97; P < 0.01). The ratio of IVDE to AME and to AMEn was 1.04 and 1.05, respectively. Predicted and determined AME or AMEn of 8 validation diets differed by less than 100 kcal/kg. The regression of determined AME or AMEn against predicted AME or AMEn (R² ≥ 0.9466; P < 0.01) resulted in an overlapped line where Y = X. These results suggest the IVDE determined with CCSDS is highly sensitive and can be used to accurately predict the ME of diets for roosters across a wide range of cereal grains.

Synergistic impact of pre-diabetes and immunosuppressants on the risk of diabetes mellitus during treatment of glomerulonephritis and renal vasculitis

Background

Glomerulonephritis is often treated with kidney-saving, but potentially diabetogenic immunosup­pressants such as glucocorticosteroids and calcineurin inhibitors. Unfortunately, there are little data on dysglycemia before and after diagnosis and during treatment of glomerulonephritis. We aimed to evaluate the occurrence and risk factors for pre-diabetes and incident diabetes among non-diabetic patients with glomerular disease with or without treatment with immunosuppressants.

Methods

A single-center, retrospective cohort study was performed on 229 non-diabetic immunosuppressant-naïve adults diagnosed with glomerulonephritis and renal vasculitis. Patients with known diabetes and prior immunosuppressant treatment were excluded. Outcomes of new-onset pre-diabetes and new-onset diabetes were defined according to American Diabetic Association criteria.

Results

Pre-diabetes was present pre-biopsy in 74 of the 229 patients (32.3%). During the median follow-up of 34.0 (23.3-47.5) months, 29 patients (12.7%) developed new-onset diabetes and 58 (25.3%) had new-onset pre-diabetes. Immunosuppressive therapy in patients with pre-existing pre-diabetes was associated with increased odds of new-onset diabetes compared to those without either risk factor (26.0% versus 5.0%; odds ratio, 6.67; 95% confidence interval [CI], 1.41 to 31.64), P = 0.02).

Conclusion

New-onset diabetes after immunosuppressant treatment occurred in one-quarter of patients with glomerulonephritis and pre-existing pre-diabetes. Physicians should screen for pre-diabetes when planning treatment with immunosuppressants, as its presence significantly increases the risk of diabetes mellitus.

P0449SERUM PROPROTEIN CONVERTASE SUBTILISIN/KEXIN TYPE 9 (PCSK9) IN NON-DIABETIC ASIANS WITH NEPHROTIC SYNDROME

Background and Aims

Nephrotic syndrome is associated with hypercholesterolemia, while its treatment, often involving high-dose glucocorticosteroids, may cause hyperglycemia. Proprotein convertase subtilisin /kexin type 9 (PCSK9) regulates plasma cholesterol and is associated with post-transplant diabetes. Although a potential therapeutic target in nephrotic syndrome, the relationships between PCSK9 and lipid parameters are not well established. We aimed to characterize serum PCSK9 and metabolic parameters among individuals with nephrotic syndrome.

Method

Single-center prospective cohort study of non-diabetic adults newly-diagnosed with nephrotic syndrome and subsequently treated with immunosuppressant. Fasting serum PCSK9 was measured using ELISA at diagnosis. Clinical history, blood pressure, body mass index (BMI), waist-to-hip ratio (WHR) and biochemistry (fasting glucose and lipid, HbA1c and fasting serum PCSK9) were obtained at diagnosis and at 3 months during immunosuppression therapy. Spearman’s correlation was used to evaluate for associations between PCSK9 and glycemic and lipid parameters.

Results

Among 15 adults with nephrotic syndrome, the majority was female (60%) and Chinese (80%). Median age was 40 (IQR 26, 51) years. The most frequent diagnoses were minimal change disease or focal segmental nephrosclerosis (n=7) and lupus nephritis (n=5); the minority had IgA nephropathy, membranous nephropathy or vasculitis. At diagnosis, median eGFR was 97.9 (59.5, 120.9) ml/min/1.73 m2, UPCR 7.6 (6.1, 10.4) g/g, LDL-cholesterol 4.6 (3.1, 6.7) mmol/L and fasting serum PCSK9 317.6 (276.8, 470.1) ng/ml. PCSK9 correlated positively with hypertriglyceridemia (r=0.55, p=0.03) at baseline.

Most patients (n=14, 93%) were treated with prednisolone (monotherapy or in combination with other immunosuppressant) and 1 received tacrolimus monotherapy. At 3 months, the majority (n= 11, 73%) had achieved clinical remission.

Fasting serum PCSK9 was higher at 3 months [median 430.6 (283.1, 496.0) ng/ml] compared to baseline, although the difference was not statistically significant. At 3 months, PCSK9 correlated positively with age (r=0.58, p=0.03), LDL-cholesterol (r=0.90, p=0.04) and change in BMI (r=0.72, p=0.01).

Conclusion

PCSK9 is associated with metabolic parameters at diagnosis and during the treatment course in patients with nephrotic syndrome treated with immunosuppressant.

P0474UTILITY OF NATIVE KIDNEY BIOPSY IN OLDER ADULTS: SAFETY AND DIAGNOSES

Background and Aims

Population aging is an increasing phenomenon worldwide and consequently more are developing kidney diseases which may necessitate diagnostic kidney biopsy. However, older patients may be at increased risk for complications such as bleeding. We aimed to examine the utility and safety of native kidney biopsies among our older adults.

Method

This was a single-centre retrospective study of older adults (≥60 years) who had native kidney biopsies at the Singapore General Hospital between June 2011 and March 2015. Demographic data, co-morbid illnesses, clinical presentation at kidney biopsy, as well as laboratory results before and after kidney biopsy, were retrieved from electronic medical records. Patient outcomes were recorded until their last visit or death before 30th March 2017. End stage renal disease (ESRD) was defined as estimated glomerular filtration rate (eGFR) &lt;15 ml/min/1.73 m2 or need for renal replacement therapy persisting &gt;3 months. All post biopsy bleeding events were documented, with major bleeding defined as the need for transfusion and/or intervention; or if bleeding was either a direct or contributory cause of death.

Results

Older adults accounted for 153 of 545 (28.1%) native renal biopsies performed. The indications for biopsy in older adults included microscopic hematuria with proteinuria (51.0%), nephrotic syndrome (32.0%) and isolated proteinuria (17.0%). One hundred and ten patients (71.9%) had eGFR &lt;60ml/min/1.72m2 at biopsy and a significantly higher proportion of older patients (85.5% vs 62.4%, p&lt;0.001) had eGFR &lt;30ml/min/1.72m2. Compared to the younger individuals &lt;60 years old, older patients were more likely to be hypertensive (86.3% vs 58.4%, p&lt;0.001) and diabetic (49.0% vs 28.1%, p&lt;0.001).

Post biopsy, major bleeding was more frequent among older adults compared with younger adults (13.3% vs 5.7% respectively; p=0.04), although overall bleeding episodes between older and younger adults were not significantly different (15.9% vs 22.9% respectively; p=0.18).

Among older adults, minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS) was the most frequent diagnosis (23.5%), followed by membranous nephropathy (20.9%) and IgA nephropathy (9.8%), whereas MCD/FSGS (26.5%), lupus nephritis (24.5%) and IgA nephropathy (19.6%) were the top three diagnoses amongst younger adults. Co-existing glomerulonephritis (GN) with diabetic nephropathy and isolated diabetic nephropathy were seen in 12 (7.8%) and 20 (13.1%) elderly patients respectively. The majority (124 patients, 81.0%) of biopsies in older adults had histological diagnoses of glomerulonephritis that were potentially amendable to treatment although only 90 (58.8%) patients subsequently received immunosuppressants.

Among older adults with biopsy-proven glomerulonephritis, median follow up was similar between those treated and not treated with immunosuppressants (30.4 [27.3, 53.7] months versus 38.8 [30.7, 51.9] months, p=0.12). Among older adults with GN, ESRD was less frequent among those treated with immunosuppressants, compared to those who did not receive immunosuppressants, although the difference did not reach statistical significance (10.3% versus 18.9%, p=0.24). However, the combined endpoint of ESRD or mortality were similar (24.1% vs 21.6%, p=0.76).

Conclusion

Our findings support the utility of renal biopsy for diagnosis and to guide clinical care. Older adults undergoing kidney biopsy should be counselled and monitored for bleeding complications.

The Value of Renal Biopsy in Non-Insulin-Dependent Diabetes Mellitus in Singapore over the Past Two Decades

Objective

This study on the prevalence of diabetic nephropathy (DN) and coexistence of non-diabetic renal disease (NDRD) in a cohort of 255 non-insulin-dependent diabetes mellitus (NIDDM) patients aims to determine the value of performing renal biopsies in these patients and elucidate the factors which could affect their progression to end-stage renal disease (ESRD).

Methods

Among 255 NIDDM patients, 93 had DN alone, 69 had NDRD alone, and the remaining 93 had DN plus NDRD (mixed group). The indications for renal biopsy were based on clinical suspicion of superimposed NDRD, including heavy or rapidly increasing proteinuria, renal impairment even though diabetes is of relatively short duration, rapidly declining renal function, and presence of hematuria with dysmorphic red blood cells suggesting presence of glomerulonephritis.

Results

The following were predictors of ESRD: high systolic BP at biopsy, longer duration of diabetes, heavy proteinuria, and presence of diabetic retinopathy. Comparing patients in the NDRD group with the DN group and the mixed group, the NDRD group had lower serum creatinine and higher eGFR with lower urinary proteinuria and higher serum albumin at presentation and on follow-up. Kimmelstiel-Wilson nodules were associated with a poorer prognosis leading to a higher occurrence of ESRD among patients with DN.

Conclusion

Renal biopsy is of value in indicating the prognosis of NIDDM patients with DN based on the diabetic lesions. For NIDDM patients with atypical course and suspicion of associated NDRD, a renal biopsy would enable us to diagnose the underlying NDRD and offer appropriate therapy. Most nephrologists would consider renal biopsy for an NIDDM patient based on clinical indications like atypical clinical course and suspicion of an associated NDRD, but they would not perform a routine renal biopsy like for a CKD patient, unless it is for a research indication.

[A sequential conditional mean model for assessing total effects of exposure in longitudinal data]

In prospective cohort study, multi follow up is often necessary for study subjects, and the observed values are correlated with each other, usually resulting in time-dependent confounding. In this case, the data generally do not meet the application conditions of traditional multivariate regression analysis. Sequential conditional mean model (SCMM) is a new approach that can deal with time-dependent confounding. This paper mainly summarizes the basic theory, steps and characteristics of SCMM.

[The association between the whole blood riboflavin level and the occurrence, development and prognosis of esophageal squamous cell carcinoma]

Objective: To investigate the association between the whole blood riboflavin level and the occurrence, development and prognosis of esophageal squamous cell carcinoma (ESCC) in China. Methods: From March 2014 to September 2018, ESCC patients from three hospitals (the Affiliated Hospital of Medical College of Shantou University, Shantou Central Hospital in Southern Chaoshan area and First Affiliated Hospital of Zhengzhou University in Northern Taihang Mountain) were selected as a case group; non-esophageal patients who had a physical examination were selected as a control group. The case and control group were paired by age (±5 years) and a 1:1 ration. A total of 1 528 subjects were enrolled including 764 patients in the case group and 764 patients in the control group. About 3-5 ml venous blood samples were collected, and the erythrocyte glutathione reductase activity coefficient (GRAC) was measured to assess the whole blood riboflavin level. A multivariate conditional logistic regression model was used to analyze the association between the GRAC and the risk of ESCC. The association between the GRAC and the prognosis of ESCC was analyzed by using Cox proportional risk regression model based on 288 patients with complete survival data. They were divided into two groups, the high GRAC group (GRAC≥7.87) group and the low GRAC group (GRAC<7.87) according to the strongest correlation between the total survival time, survival outcome and GRAC (GRAC=7.87). Results: Among the 1 528 patients, 958 patients were from Southern Chaoshan area, including 479 patients in the case group with an average age about (59.90±9.34) years and 479 patients in the control group with an average age about (59.55±8.77) years. Other 570 patients were from Northern Taihang Mountain area, including 285 patients in the case group with an average age (58.39±5.19) years and 285 patients in the control group with an average age about (58.74±4.57) years. The multivariate conditional logistic regression showed that the OR (95%CI) of the GRAC and the risk of ESCC was 1.009 (0.998-1.019). The Cox proportional hazard regression model analysis showed that the HR (95%CI) of the high GRAC group was 1.712 (1.034-2.824) compared with the low GRAC group in the 50-70 years group. Conclusion: The whole blood riboflavin level might not be associated with the occurrence of ESCC. The high whole blood riboflavin level would be more beneficial to the prognosis of ESCC patients aged 50-70 years.

[Application of parametric g-formula in causal analysis]

At present, traditional methods on statistics have limitations in controlling time- varying confounding. This paper introduces an analysis method, parametric g-formula, which would adjust time-varying confounding, and also exemplifies the steps of its implementation for purpose to provide a new reference for researchers to deal with long-term observational data.

[A new mediation analysis method for multiple mediators]

Mediation analysis is mainly used to explore the causal mechanism between independent variable X and dependent variable Y. It determines whether mediator M plays a role and evaluate the role's degree in the causal path by decomposing the causal path between the independent variable X and the dependent variable Y. However, the classical mediation analysis is generally used for single mediator. This paper introduces a new mediation analysis method for multiple mediators.

Infections in hospitalized lupus nephritis patients: characteristics, risk factors, and outcomes

Background There are limited studies documenting infection epidemiology in lupus nephritis (LN) patients. We aimed to study infection incidences and risk characteristics and ascertain possible predictors of infective outcomes in a multiethnic Asian population. Methods This retrospective study from 2006 to 2012 included newly diagnosed LN patients. We collected admissions, immunosuppression, and infection data until end-stage renal failure, death, last follow-up, or the year 2015. The infection incidence rates were evaluated and a generalized linear latent and mixed models (GLLAMM) analysis was carried out to evaluate potential predictors of infection. Results Our cohort of 101 patients consisted of mainly Chinese (75.2%), females (78.2%), and a median age of 38 years (IQR 26-49). The median time of follow-up was 72.8 months (IQR 49.5-94.0). Six out of 14 patient deaths were infection related. Seventy-eight out of 200 admissions, with a total of 102 episodes of infection, occurred in 46 patients. The incidence of infection rates leading to admissions was 10.3 per 100 person-years and the incidence of infection episodes rates was 17.6 per 100 person-years. Cytomegalovirus (CMV) was the most common organism identified. Univariate GLLAMM analysis showed Malay compared to Chinese ethnicity (HR 2.833 (95% CI 1.088-7.373)), use of oral cyclophosphamide (HR 6.618 (95% CI 1.015-43.154)) and rituximab (HR 3.967 (95% CI 1.157-13.603)) as predictors of infection-related admissions. Malay ethnicity and rituximab remained significant in the multivariate GLLAMM analysis. Conclusions Our study highlights substantial infection incidences in patients with LN and its contribution to deaths.

[Research of prevalence of schistosomiasis in Hunan province, 1984-2015]

Objective: To analyze the prevalence of schistosomiasis in Hunan province, and provide scientific evidence for the control and elimination of schistosomiasis. Methods: The changes of infection rates of Schistosoma (S.) japonicum among residents and cattle in Hunan from 1984 to 2015 were analyzed by using dynamic trend diagram; and the time regression model was used to fit the infection rates of S. japonicum, and predict the recent infection rate. Results: The overall infection rates of S. japonicum in Hunan from 1984 to 2015 showed downward trend (95.29% in residents and 95.16% in cattle). By using the linear regression model, the actual values of infection rates in residents and cattle were all in the 95% confidence intervals of the value predicted; and the prediction showed that the infection rates in the residents and cattle would continue to decrease from 2016 to 2020. Conclusion: The prevalence of schistosomiasis was in decline in Hunan. The regression model has a good effect in the short-term prediction of schistosomiasis prevalence.

[Influence of social support and coping style on chronic post-traumatic stress disorder after floods]

OBJECTIVE

To explore the long-term prognosis and influence of social support and coping style of patients with post-traumatic stress disorder (PTSD) after suffering from floods.

METHODS

Patients suffered PTSD due to Dongting lake flood in 1998 were selected through cluster random sampling. PTSD scale civilian version (PCL-C) was used to examine and diagnose the participants in this study. PTSD was then evaluated by the social support rating scale (SSRS) and the simple coping style questionnaire (SCSQ).

RESULTS

Among all the 120 subjects, 14(11.67%) of them were diagnosed as having PTSD. Compared with the rehabilitation group, scores on subjective support, objective support, total social support and positive coping, total of coping style from the non-rehabilitation group all appeared significant low (P<0.05). Data from the multivariate logistic regression showed that social support (OR=0.281, 95% CI: 0.117-0.678) and coping style (OR= 0.293, 95% CI: 0.128-0.672) were protective factors of the chronic PTSD after the floods while disaster experience (OR=1.626, 95%CI: 1.118-2.365) appeared as a risk factor.

CONCLUSION

Chronic PTSD developed after the floods called for attention. Better social support, positive coping style could significantly improve the long-term prognosis of patients with PTSD after the floods.

Effect of skeletal muscle fibers on porcine meat quality at different stages of growth

In this study, we examined changes in meat quality and content of muscle types during porcine growth. The influence of the longissimus dorsi muscle fiber composition on meat quality and the correlation between 2 fiber-typing methods (histochemistry and real-time quantitative polymerase chain reaction) were examined. Type IIx and type IIb fibers accounted for most of the total number of fibers; the proportion of these fibers increased during porcine growth (75.42, 80.09, and 79.88%, respectively, at 3 different stages of growth). There was a strong positive correlation between the 2 fiber-typing methods; the correlation coefficients of type I, IIa, and IIx+IIb fiber contents were 0.65, 0.88, and 0.92, respectively. The a* value of meat color was significantly lower at 98 days and negatively correlated with white fiber content (r = -0.69, P < 0.01). Water-holding capacity decreased during porcine growth. The drip loss parameter was positively correlated with type IIx+IIb fiber content (r = 0.55, P < 0.05). Decreased pH was strongly positively correlated with type IIx+IIb fiber content (r = 0.61, P < 0.01) and negatively correlated with type IIa fiber content (r = -0.44, P < 0.05). Therefore, we found that the composition of muscle fibers influenced the establishment of meat quality and its alteration during the early postmortem period.

Developing a computer-controlled simulated digestion system to predict the concentration of metabolizable energy of feedstuffs for rooster

Four experiments were conducted to evaluate the effectiveness of a computer-controlled simulated digestion system (CCSDS) for predicting apparent metabolizable energy (AME) and true metabolizable energy (TME) using in vitro digestible energy (IVDE) content of feeds for roosters. In Exp. 1, the repeatability of the IVDE assay was tested in corn, wheat, rapeseed meal, and cottonseed meal with 3 assays of each sample and each with 5 replicates of the same sample. In Exp. 2, the additivity of IVDE concentration in corn, soybean meal, and cottonseed meal was tested by comparing determined IVDE values of the complete diet with values predicted from measurements on individual ingredients. In Exp. 3, linear models to predict AME and TME based on IVDE were developed with 16 calibration samples. In Exp. 4, the accuracy of prediction models was tested by the differences between predicted and determined values for AME or TME of 6 ingredients and 4 diets. In Exp. 1, the mean CV of IVDE was 0.88% (range = 0.20 to 2.14%) for corn, wheat, rapeseed meal, and cottonseed meal. No difference in IVDE was observed between 3 assays of an ingredient, indicating that the IVDE assay is repeatable under these conditions. In Exp. 2, minimal differences (<21 kcal/kg) were observed between determined and calculated IVDE of 3 complete diets formulated with corn, soybean meal, and cottonseed meal, demonstrating that the IVDE values are additive in a complete diet. In Exp. 3, linear relationships between AME and IVDE and between TME and IVDE were observed in 16 calibration samples: AME = 1.062 × IVDE - 530 (R(2) = 0.97, residual standard deviation [RSD] = 146 kcal/kg, P < 0.001) and TME = 1.050 × IVDE - 16 (R(2) = 0.97, RSD = 148 kcal/kg, P < 0.001). Differences of less than 100 kcal/kg were observed between determined and predicted values in 10 and 9 of the 16 calibration samples for AME and TME, respectively. In Exp. 4, differences of less than 100 kcal/kg between determined and predicted values were observed in 3 and 4 of the 6 ingredient samples for AME and TME, respectively, and all 4 diets showed the differences of less than 25 kcal/kg between determined and predicted AME or TME. Our results indicate that the CCSDS is repeatable and additive. This system accurately predicted AME or TME on 17 of the 26 samples and may be a promising method to predict the energetic values of feed for poultry.

Nutrient density and slaughter age have differential effects on carcase performance, muscle and meat quality in fast and slow growing broiler genotypes

1. A 2 × 2 factorial design was used to investigate the differences in carcase, muscle and meat characteristics between fast and slow growing genotypes fed on low nutrient (LND) or high nutrient diets (HND) at their respective slaughter ages. 2. The birds were randomly assigned to treatments with 5 replicates of 145 birds for Wens Yellow-Feathered Chicken (WYFC, 5·75 birds/m(2)) or 115 birds for White Recessive Rock Chicken (WRRC, 7·25 birds/m(2)), according to the commercial recommendations for the two breeds and were fed on HND or LND. Birds were slaughtered at 63 d and 105 d of age. 3. The results showed WRRC had higher carcase yield and meat yield than that of WYFC, lower fat content, higher moisture content and lower cooking loss. The meat from WRRC was less tender and contained lower levels of polyunsaturated fatty acids (PUFA). 4. Birds fed on HND had higher breast meat yield, myofiber area and protein content in the breast muscle and lower fat content than birds fed on LND. The thigh muscle of birds fed on HND had higher levels of PUFA. Age had a positive effect on carcase parameters, but a negative effect on pH, meat tenderness and cooking loss, and the two genotypes exhibited different responses to the influence of nutrient density and age. 5. Genotype and age had the largest effect on carcase performance and meat quality. LND benefited meat quality and WRRC had larger responses in meat yield and shear force when fed on HND.

Discrimination of real and virtual surfaces with sinusoidal and triangular gratings using the fingertip and stylus

Two-interval two-alternative forced-choice discrimination experiments were conducted separately for sinusoidal and triangular textured surface gratings from which amplitude (i.e., height) discrimination thresholds were estimated. Participants (group sizes: n = 4 to 7) explored one of these texture types either by fingertip on real gratings (Finger real), by stylus on real gratings (Stylus real), or by stylus on virtual gratings (Stylus virtual). The real gratings were fabricated from stainless steel by an electrical discharge machining process while the virtual gratings were rendered via a programmable force-feedback device. All gratings had a 2.5-mm spatial period. On each trial, participants compared test gratings with 55, 60, 65, or 70 μm amplitudes against a 50-μm reference. The results indicate that discrimination thresholds did not differ significantly between sinusoidal and triangular gratings. With sinusoidal and triangular data combined, the average (mean + standard error) for the Stylus-real threshold (2.5 ± 0.2 μm) was significantly smaller (p <; 0.01) than that for the Stylus-virtual condition (4.9 ± 0.2 μm). Differences between the Finger-real threshold (3.8 ± 0.2 μm) and those from the other two conditions were not statistically significant. Further studies are needed to better understand the differences in perceptual cues resulting from interactions with real and virtual gratings.

Effects of dietary protein source on the digestive enzyme activities and electrolyte composition in the small intestinal fluid of chickens

An experiment was conducted to investigate the effects of dietary protein source on the digestive enzymes and electrolyte composition of digesta fluid in the duodenum, jejunum, and ileum of chickens. A 2 × 3 factorial and completely randomized design that used 2 types of diets that differed only in their protein source [a corn-soybean meal-miscellaneous meal diet (CSMD) and a corn-miscellaneous meal diet (CMD)] and 3 types of cannulated roosters (duodenal, jejunal, and ileal cannulations) was adopted. The experiments included 5 replicates for each of the 6 treatments, and each replicate involved 3 cannulated chickens. The digesta samples were collected for 1 h every 4 h between 09:30 and 18:30 h on d 31, 33, and 35 of the experiment. The amylase, lipase, trypsin, and chymotrypsin activities and the electrolyte composition in the duodenal, jejunal, and ileal fluid were determined. In general, no significant differences between the 2 dietary groups were observed for the mean of duodenal, jejuna, and ileal amylase, trypsin, chymotrypsin, and lipase, respectively. However, the duodenal amylase activity was lower in the CMD group than the CSMD group (P < 0.05), which was probably related to the lower duodenal pH value that was observed in this group (P < 0.01). A higher jejunal Mg(2+) concentration was observed in chickens that were fed the CMD (P < 0.05), whereas the differences in the Na(+), K(+), Cl(-), and Ca(2+) concentrations in the small intestine were not significant between the 2 diets (P > 0.05). In conclusion, the digestive enzymes and electrolytes in the small intestinal fluid of chickens adapted to the protein source of the diet, and each segment of the small intestine displayed different modifications.