Cross-cultural translation into Chinese and psychometric evaluation of a screening tool for nocturia: the Targeting the individual's Aetiology of Nocturia to Guide Outcomes (TANGO) questionnaire.

INTRODUCTION: We conducted translation and psychometric validation of a self-administered, 22-item dichotomous response-based questionnaire to identify nocturia aetiologies and co-morbidities in adult patients. METHODS: The Targeting the individual's Aetiology of Nocturia to Guide Outcomes (TANGO) questionnaire was forward- and backward-translated, then finalised using a standardised methodology. The resulting version, a Chinese version of the TANGO [TANGO (CV)], was evaluated for internal consistency, test-retest reliability, content validity, convergent validity, criterion validity, and discriminant validity via responses from 65 participants (46 men and 19 women; mean age, 67 years, range, 50-88), in comparison with other validated questionnaires and a 4-day bladder/sleep diary. RESULTS: Only 0.4% of responses were missing; 3% of participants required assistance with comprehension. The Kuder-Richardson Formula 20 (KR-20) coefficient for the whole tool was 0.711. Kappa values for individual domains and the whole tool varied from 0.871 to 0.866, indicating satisfactory test-retest reliability. There was strong agreement between the sum of positive responses to each domain and the whole tool (intra-class correlation coefficient=0.878-1.000). Modest correlations (ρ=0.4-0.6) were detected between the tool and bladder/sleep diary-based parameters for convergent validity. Criterion validity was confirmed for each domain and the whole tool [ρ=0.287-0.687]. In receiver operating characteristic analysis, the tool could distinguish patients (≥2 nocturia episodes/night) from controls (≤1 nocturia episode/night) [Youden's J statistic=0.453, area under the curve=0.818, 95% confidence interval (CI)=0.683-0.953] and patients with significant nocturia distress from patients with mild nocturia distress (Youden's J statistic=0.398, area under the curve=0.729, 95% CI=0.581-0.878). CONCLUSION: The TANGO (CV) was formally crossculturally adapted and translated. Its psychometric properties (except sensitivity to change) were validated.

Effects of coated sodium butyrate on growth performance, intestinal morphology, and caecal short-chain fatty acids of growing Pekin ducks.

1. A dose‒response experiment with six supplemental levels of coated sodium butyrate (CSB) (0, 250, 500, 750, 1,000, and 1,250 mg/kg) was conducted to investigate its effects on growth performance, intestinal morphology, and caecal short-chain fatty acids of growing Pekin ducks aged 14 to 35 d. A total of 288 male 14-d-old Pekin ducks were randomly allocated to six dietary treatments. Each treatment had eight replicate pens of six ducks per pen.2. The daily weight gain, daily feed intake, and feed/gain of ducks from 14 to 35 d of age were not influenced by increasing CSB levels. The relative weight and length of the duodenum, jejunum, and caecum increased linearly or quadratically as supplemental CSB increased (P < 0.05).3. For the ileum and caecum, the villus height and height/crypt depth increased linearly or quadratically, and the villus crypt depth decreased linearly as the supplemental CSB increased (P < 0.05). As supplemental CSB increased, the goblet cell numbers of the ileum increased and decreased and changed quadratically (P < 0.05), but caecal goblet cell number increased quadratically (P < 0.05). Increasing the CSB level linearly or quadratically elevated the concentrations of propionic acid and butyric acid in the caecum (P < 0.05).4. It was concluded that CSB can be used as a safe and effective feed additive to promote the intestinal integrity of growing ducks by improving intestinal morphology and increasing the concentration of caecal short-chain fatty acids.

[Reliability and validity of the Chinese version of adverse childhood experiences international questionnaire in parents of preschool children].

OBJECTIVE: To test the reliability and validity of the Chinese version of adverse childhood experiences international questionnaire (ACE-IQ) in Chinese parents of preschool children. METHODS: The parents of preschool children in 6 kindergartens in Tongzhou District of Beijing were selected by stratified random cluster sampling, and the Chinese version of ACE-IQ after translation and adaptation was used for survey online. The collected data were randomly divided into two parts. One part of the data (n=602) was used for exploratory factor analysis (EFA), to screen items and evaluate structural validity, and then form the final Chinese version of ACE-IQ. The other part of the data (n=700) was used for confirmatory factor analysis (CFA), criterion validity analysis and reliability analysis. At the same time, experts investigation method was used to evaluate the content validity of the final Chinese version of ACE-IQ. RESULTS: After deleting four items of collective violence, the Chinese version of ACE-IQ with twenty-five items indicated good structural, criterion and content validity. Analysis results showed that the Chinese version of ACE-IQ presented a seven-factor model dimension, namely emotional neglect, physical neglect, family dysfunction, family violence, emotional and physical abuse, sexual abuse and violence outside the home, and the total score of the binary version of ACE-IQ Chinese version was positively correlated with the total score of childhood trauma questionaire-28 item short form (CTQ-SF, r=0.354, P < 0.001) and the center for epidemiological studies depression scale (CES-D, r=0.313, P < 0.001) respectively. Results from five experts showed that the item-level content validity index (I-CVI) of 25 items was between 0.80 and 1.00, and the average of all I-CVIs on the scale (S-CVI/Ave) of the scale was 0.984. At the same time, the internal consistency (Cronbach's α coefficient) of the whole scale was 0.818, and the split-half reliability (Spearman-Brown coefficient) was 0.621, which demonstrated good reliability. CONCLUSION: This study has formed a Chinese version of ACE-IQ with 25 items and 7 dimensions, which has good reliability and validity among the parents of preschool children in China. It can be used as an evaluation instrument for measuring the minimum threshold of the adverse childhood experiences in the parents of preschool children in the cultural background of China.

Separating and trapping of chiral nanoparticles with dielectric photonic crystal slabs.

Chiral separation is a crucial step in many chemical synthesis processes, particularly for pharmaceuticals. Here we present a novel method for the realization of both separating and trapping of enantiomers using the dielectric photonic crystal (PhC) slabs, which possess quasi-fourfold degenerate Bloch modes (overlapping double degenerate transverse-electric-like and transverse-magnetic-like modes). Based on the designed structure, a large gradient of optical chirality appears near the PhC slab, leading to the extreme enhancement of chiral optical forces about 3 orders of magnitude larger than those obtained with circularly polarized lights. In this case, our method provides a reference for realizing all-optical enantiopure syntheses.

Attitudes, acceptance, and registration in relation to organ donation in Hong Kong: a cross-sectional study.

INTRODUCTION: The objective of this study was to investigate the discrepancy between individuals with positive attitudes towards organ donation and the actual number of registered organ donors in Hong Kong, and to investigate the best modalities for promoting more organ donor registrations. METHODS: This cross-sectional telephone survey was conducted in Hong Kong. Telephone numbers were selected randomly. Upon successful contact with a household, the eligible household member who had the most recent birthday was selected to participate in the telephone interview. RESULTS: A total of 1000 Hong Kong Chinese residents were interviewed successfully. The response rate was 53.8%. The majority of the respondents were female (68.3%) and were aged 51 to 60 years (24%) or ≥61 years (43.6%). Among the respondents, 31.3% were willing to donate their organs after death; 43.3% were indecisive, and 25.4% refused. Among those who were willing to donate organs after death, only 34.2% had registered with the Centralised Organ Donation Register (CODR). Among those who were willing to donate organs after death but had not yet registered on CODR, 52.2% said they were not determined enough to take action, 47.8% said they were too busy, 37.8% said they were too lazy, and 20.4% said they were always forgetful about registering. In all, 32.8% of the interviewees were not aware of the ways to register as a prospective organ donor. Among non-messenger social media platforms, Facebook, YouTube, and Instagram were the most commonly used. Most participants believed that Facebook and YouTube were effective for engaging audiences. CONCLUSIONS: More effort should be made to facilitate organ donor registration in face-to-face settings via promotional booths and in online settings via appropriate social media platforms.

[Research progress of ferroptosis-related mechanism and diseases].

Ferroptosis is a new programmed cell death characterized by iron dependent and intracellular oxidative accumulation. Current studies have confirmed that ferroptosis is involved in the occurrence and development of neurotoxicity injury, tumors, cardiovascular diseases and other diseases. This paper reviews the mechanisms of ferroptosis and its role in related diseases based on recent studies.

Survey on prevalence of lower urinary tract symptoms in an Asian population.

INTRODUCTION: Lower urinary tract symptoms (LUTS) have a strong effect on socio-economic and individual quality of life. The aim of the present study was to investigate the prevalence of LUTS in an Asian population. METHODS: A telephone survey of individuals aged ≥40 years and of Chinese ethnicity was conducted. The survey included basic demographics, medical and health history, drinking habits, International Prostate Symptom Score, overactive bladder symptom score, Patient Health Questionnaire (PHQ-9) score, and Short Form (SF)-12v2 score. RESULTS: From March to May 2017, 18 881 calls were made, of which 1543 fulfilled the inclusion criteria. In the end, 1000 successful respondents were recruited (302 men and 698 women). Age-adjusted prevalence of overactive bladder syndrome was 15.1%. The older the respondent, the more prevalent the storage symptoms and voiding symptoms (storage symptoms: r=0.434, P<0.001; voiding symptom: r=0.190, P<0.001). Presence of hypertension and diabetes were found to be significantly and positively correlated with storage and voiding symptoms. Storage and voiding symptoms were found to affect PHQ-9 scores (storage symptoms: r=0.257, P<0.001; voiding symptoms: r=0.275, P<0.001) and SF-12v2 scores (storage symptoms: r=0.467, P<0.001; voiding symptoms: r=0.335; P<0.001). Nocturia was the most prominent symptom among patients who sought medical help for their LUTS. CONCLUSIONS: Lower urinary tract symptoms are common in Asian populations. Both storage and voiding symptoms have a negative impact on mental health and general well-being of individuals.

Effects of ambient temperature on growth performance and carcass traits of male growing White Pekin ducks.

1. An experiment was conducted to investigate the effects of ambient temperature on growth performance and carcass traits in male growing Pekin ducks from 14 to 42 d of age in order to establish their optimal temperature requirements. 2. A total of 216 14 d old male White Pekin ducks were allocated randomly to six environmentally controlled chambers with ambient temperature set at 20°C, 22°C, 24°C, 26°C, 28°C, and 30°C from 14 to 42 d of age, respectively. 3. As ambient temperature increased from 20°C to 30°C, the body weight and weight gain decreased linearly or quadratically (P < 0.05) and was accompanied by linearly decreasing feed intake (P < 0.05). According to broken-line regression, the upper critical level of ambient temperature during the growing period for body weight, weight gain, and feed conversion ratio were 27.4°C, 27.4°C, and 26.0°C, respectively. 4. The weight of breast meat, leg meat, and abdominal fat decreased linearly or quadratically as ambient temperature increased and declined to a minimum when the temperature increased to 30°C (P < 0.05). The percentage of breast meat and abdominal fat showed a linear or quadratic decreasing response to increasing temperature, but leg meat percentage increased as temperature increased and reached maximum at 30°C (P < 0.05). According to broken-line regression, the upper critical ambient temperatures during the growing period for breast meat weight and percentage were 25.5°C and 25.6°C, respectively. 5. It was concluded that both growth performance and breast meat of growing ducks were sensitive to increasing ambient temperature and this should be kept below the upper critical temperature during the growing period in order to optimise growth performance and carcass traits at market age.

Threonine supplementation reduces dietary protein and improves lipid metabolism in Pekin ducks.

1. This study was conducted to investigate the efficiency of threonine (Thr) supplementation on reducing dietary crude protein (CP) content and the effects of Thr on lipid metabolism in Pekin ducks. The effects of dietary CP concentration (160, 190 and 220 g/kg) and Thr supplemental concentration (0, 0.7, 1.4, 2.1 and 2.8 g/kg) on growth performance, carcass, liver lipid and plasma profiles were determined in Pekin ducks from 1-21 d of age. 2. A total of 720-d-old male Pekin ducks were randomly allotted to 1 of 15 dietary treatments with 6 replicate cages of 8 birds per cage for each treatment according to average body weight. 3. Dietary Thr supplementation improved growth performance and breast muscle percentage at all CP diets, and ducks fed Thr-supplemented diets had higher plasma concentrations of some plasma amino acids. Thr supplementation reduced the concentrations of total lipid, triglyceride, cholesterol in liver, and plasma low density lipoprotein cholesterin concentration at 160 and 190 g/kg CP, whereas it increased triglyceride concentration at 160 g/kg CP. 4. Thr requirements based on quadratic broken-line model estimation were 6.6 and 7.0 g/kg for optimal average daily gain (ADG), and 6.7 and 7.3 g/kg for breast muscle percentage of Pekin ducks from 1-21 d of age at 190 and 220 g/kg CP, respectively. The dietary Thr requirements and estimated ADG (55.18 vs. 55.86 g/d/bird) and breast muscle percentage (2.79% vs. 2.75%) of Pekin ducks did not differ between 190 and 220 g/kg CP according to the t-test results. 5. Dietary CP level could be reduced to 190 g/kg in Pekin ducks from 1-21 d of age with Thr supplementation to balance dietary amino acids, and Thr supplementation prevented excess liver lipid deposition in this instance.

Relationship between estrogen receptor 1 gene polymorphisms and postmenopausal osteoporosis of the spine in Chinese women.

The purpose of this study was to evaluate single nucleotide polymorphism (SNP) variants of the estrogen receptor 1 gene (ESR1) at rs2234693 and rs9340799, as well as to investigate the relationship between ESR gene polymorphisms and postmenopausal osteoporosis (OP) of the spine in Chinese women. We recruited 198 postmenopausal women with OP and 276 healthy women between May 2012 and September 2015 in Zhongshan Hospital. Dual energy x-ray absorptiometry was used to measure the bone mineral density (BMD) of the lumbar vertebrae in all subjects. In addition, PCR-restriction fragment length polymorphism based analysis was conducted to identify the genotypes of ESR1. The distribution of ESR1 in the osteoporosis group and the control group was determined; the relationship between ESR polymorphisms and BMD was analyzed. The distributions of BMD were: TT < TC < CC, GG < AG < AA. The TT, TTGG, and TCGG genotypes were found to be lower as compared to the other genotypes. Stratified analysis suggested that the TT genotype and the combined genotypes TTGG and TCGG were significantly higher in the OP group as compared to the control group (P < 0.01). Therefore, ESR1 polymorphisms at rs2234693 and rs9340799 may be associated with OP, and could be used as markers to screen those with high risks to postmenopausal OP in Chinese women.

Effects of full-fat rice bran inclusion in diets on growth performance and meat quality of Sichuan goose.

This trial was conducted to study the effect of full-fat rice bran inclusion in diets on growth performance, carcass and meat quality and fatty acid composition in Sichuan goose. A total of 204 Sichuan white male geese (28-d-old, 984 ± 15 g) were used in the 42-d assay. Full-fat rice bran inclusion in diets was 0%, 6%, 12% and 18%, respectively. On d 70, two geese from each pen were randomly selected and killed for measuring the carcass and meat quality and the meat fatty acid composition. The results showed that full-fat rice bran inclusion had no effect on average daily gain during 28-56 d, but rice bran inclusion at 18% increased average daily gain during 57-70 d. In addition, the full-fat rice bran supplementation decreased the subcutaneous fat yield, and the inclusion of full-fat rice bran in amounts of 12% and 18% decreased the half-eviscerated carcass yield, eviscerated carcass yield and crude fat content in goose meat. Moreover, full-fat rice bran supplementation had no effect on the content of total saturated fatty acid (SFA), but decreased the content of total monounsaturated fatty acid (MUFA). The inclusion of full-fat rice bran in amounts of 12-18% increased the content of total polyunsaturated fatty acid (PUFA) and total n-6 in goose meat and in the amount of 18% increased n-3 fatty acids content in goose meat. The results indicated that the rice bran inclusion had a positive effect in geese by stimulating growth performance and improving meat quality and fatty acid composition of goose meat.

Effects of Dietary Methionine Levels on Choline Requirements of Starter White Pekin Ducks.

A 2×5 factorial experiment, using 2 dietary methionine levels (0.28% and 0.48%) and 5 dietary choline levels (0, 394, 823, 1,239, and 1,743 mg/kg), was conducted to study the effects of dietary methionine status on choline requirements of starter white Pekin ducks from 7 to 28 days of age. Four hundred eighty 7-d-old male White Pekin ducks were randomly allotted to ten dietary treatments, each containing 6 replicate pens with 8 birds per pen. At 28 d of age, weight gain, feed intake, and feed/gain were measured and the legs of all ducks from each pen were examined for incidence of perosis. Perosis and growth depression were observed in choline-deficient ducks and supplementation of choline reduced perosis and significantly increased weight gain and feed intake regardless of dietary methionine levels (p<0.05). In addition, significant positive effects of dietary methionine supplementation on weight gain, feed intake, and feed/gain were observed at any choline level (p<0.05). Supplementation of 1,743 mg/kg choline in diets alleviated the depression of weight gain and feed intake caused by methionine deficiency at 0.28% methionine level. The interaction between choline and methionine influenced weight gain and feed intake of ducks (p<0.05). At 0.28% methionine level, 1,743 mg/kg choline group caused 4.92% and 3.23% amount of improvement in weight gain and feed intake compared with 1,239 mg/kg choline group, respectively. According to the broken-line regression, the choline requirements of starter Pekin ducks for weight gain and feed intake were 1,472 and 1,424 mg/kg at 0.28% methionine level and 946 and 907 mg/kg at 0.48% methionine level, respectively. It suggested the choline recommendations of starter Pekin ducks on a semi-purified diet were 1448 mg/kg at 0.28% methionine level and 927 mg/kg at 0.48% methionine level, respectively. Compared with the adequate methionine level, menthionine deficiency markedly increased the choline requirements of ducks.

Hepatic phosphoenolpyruvate carboxykinase expression after gastric bypass surgery in rats with type 2 diabetes mellitus.

The objective of this study was to investigate the mRNA expression of hepatic phosphoenolpyruvate carboxykinase (PEPCK) after gastric bypass surgery (GBS) in rats with type 2 diabetic mellitus (T2DM). Thirty-six male Goto-Kakizaki rats, aged 12 weeks, were randomly divided into the GBS, sham operation with diet restriction (SO), and sham operation alone (control) groups (N = 12 per group). Liver specimens from all rats were obtained during the operation and 8 weeks after operation. Blood lipid levels were measured before and 8 weeks after operation. Fasting blood glucose (FBG), food intake, and body weight were recorded at weekly time points after operation. The blood glucose area under the curve (AUC) was calculated, and insulin sensitivity indices (ISI) were assessed. The expression PEPCK mRNA and protein were measured by real-time polymerase chain reaction and western blot. Compared with those of the SO and control groups, the blood lipid levels and the FBG in the GBS group was significantly decreased (P < 0.05), as was the AUC (P < 0.05), whereas the ISI was significantly increased (P < 0.05). PEPCK mRNA and protein levels in the GBS group were lower than those in the control group, whereas those in the SO group were significantly higher than those in controls (P < 0.05). In conclusion, GBS can reduce blood glucose in T2DM rats while improving glucose tolerance and hyperglycemia, and the mechanism appears to be associated with a decrease of hepatic PEPCK mRNA and protein expression.

Characterization of MUSTN1 gene and its relationship with skeletal muscle development at postnatal stages in Pekin ducks.

Musculoskeletal embryonic nuclear protein 1 (MUSTN1) gene is involved in myogenic fusion and differentiation in rats. We previously showed the differential expression of MUSTN1 in week (W) 2 and W6 breast muscles of Pekin ducks. In this study, we further investigated its molecular characteristics and expression profiles in different tissues at W7 and in breast and leg muscles at W1, W3, W5, W7, and W9. The relationship between muscle development and muscle fiber areas was also investigated. A 358-bp cDNA sequence was obtained. The coding sequence of duck MUSTN1 cDNA encoded a 78-amino acid sequence, which showed high similarity with those of other species (96% similarity with zebra finch and 94% with chicken). In addition, a 6435-bp genomic DNA sequence of MUSTN1 was obtained. In total, 231 transcription factor-binding sites were found in the promoter region, and many of these transcription factors were involved in the regulation of muscle development. MUSTN1 expression in breast muscle increased from W1 to W5 and then decreased at W9. In leg muscle, the expression increased from W1 to W3 and then decreased. The relative growth rates of breast and leg muscle fibers reached their peaks at W3-W5 and W1-W3, respectively. Since the greatest relative growth rates appeared at the highest expression levels of the MUSTN1 gene, it was thought to play roles in duck muscle development. Our findings would be helpful in understanding the molecular characteristics and functions of the MUSTN1 gene in breast muscle development of ducks.

Choline requirements of White Pekin ducks from hatch to 21 days of age.

A dose-response experiment with 8 dietary choline levels (302, 496, 778, 990, 1,182, 1,414, 1,625, and 1,832 mg/kg) was conducted with male White Pekin ducks to estimate the choline requirement from hatch to 21 d of age. Three hundred eighty-four 1-d-old male White Pekin ducks were randomly assigned to 8 dietary treatments, each containing 6 replicate pens with 8 birds per pen. At 21 d of age, weight gain, feed intake, and feed/gain from each pen were calculated for feeding period, and 2 ducks selected randomly from each pen were euthanized and the liver was collected to determine total lipids, triglycerides, and phospholipids. In our study, perosis, poor growth, and high liver fat were all observed in choline-deficient ducks and incidence of perosis was zero when dietary choline was 1,182 mg/kg. As dietary choline increased, the weight gain and feed intake increased linearly or quadratically (P < 0.05). On the other hand, as dietary choline increased, the total lipid and triglyceride in liver decreased linearly and liver phospholipid increased linearly (P < 0.05), and the lipotropic activity of choline may be associated with increasing phospholipid at a high dietary choline level. According to broken-line regression, the choline requirements for weight gain and feed intake were 810 and 823 mg/kg, respectively, but higher requirement should be considered to prevent perosis and excess liver lipid deposition completely.

Effects of stocking density on growth performance, carcass traits, and foot pad lesions of White Pekin ducks.

Two experiments were conducted to study the effects of stocking density on growth performance, carcass yield, and foot pad lesions of White Pekin ducks from hatch to 14 d of age (experiment 1) and from 14 to 42 d of age (experiment 2), respectively. All ducks were reared in raised plastic wire-floor pens with a pen size of 30 m(2), and males and females were mixed at a ratio of 1:1 in each pen of both experiments. In experiment 1, a total of 10,200 ducks that were 1 d old were allotted to 20 pens according to the stocking densities of 13, 15, 17, 19, and 21 birds/m(2) (or 8.4, 9.7, 10.9, 11.9, and 13.0 kg of actually achieved BW/m(2)), respectively, with 4 replicates per treatment. In experiment 2, a total of 3,150 ducks that were 14 d old were allotted to 15 pens according to the stocking densities of 5, 6, 7, 8, and 9 birds/m(2) (or 17.0, 20.3, 23.6, 26.9, and 29.9 kg of actually achieved BW/m(2)), respectively, with 3 replicates per treatment. The stocking density had significant effects on final BW and weight gain of starter and growing ducks (P < 0.05), but not on feed/gain and mortality in both periods (P > 0.05). The final BW and weight gain of starter and growing ducks all decreased with increasing density (P < 0.05). Final BW and weight gain of starter ducks were reduced significantly as stocking density increased from 17 to 21 birds/m(2) (P < 0.05). In addition, final BW and weight gain of growing ducks decreased significantly when stocking density was 9 birds/m(2) (P < 0.05). On the other hand, increasing stocking density did not markedly influence the carcass, breast meat, leg meat, abdominal fat, and foot pad lesions of growing ducks (P > 0.05).

Arginine affects appetite via nitric oxide in ducks.

The objective of the study was to investigate the mechanism by which arginine regulates feed intake in Pekin ducks. In experiment 1, one hundred forty-four 1-d-old male Pekin ducks were randomly allotted to 3 dietary treatments with 6 replicate pens of 8 birds per pen. Birds in each group were fed a corn-corn gluten meal diet containing 0.65, 0.95, and 1.45% arginine. Ducks fed the diet containing 0.65% arginine had lower feed intake and plasma nitric oxide level (P < 0.05) than the other 2 groups. In experiment 2, twenty 11-d-old ducks were allotted to 1 of 2 treatments. After 2 h fasting, birds in the 2 groups were intraperitoneally administrated saline and l-NG-nitro-arginine methyl ester HCl (L-NAME) for 3 d, respectively. Feed intake (P < 0.07) and plasma nitric oxide concentration (P < 0.05) 2 h postinjection in the L-NAME administered group were lower than those of the control group. In conclusion, the study implied that arginine modifies feeding behavior possibly through controlling endogenous synthesis of nitric oxide in Pekin ducks.

Using a computer-controlled simulated digestion system to predict the energetic value of corn for ducks.

Two experiments were conducted to develop a computer-controlled digestion system to simulate the digestion process of duck for predicting the concentration of ME and the metabolizability of gross energy (GE) in corn. In a calibration experiment, 30 corn-based calibration samples with a previously published ME concentration in 2008 were used to develop the prediction models for in vivo energetic values. The linear relationships were established between in vivo ME concentration and in vitro digestible energy (IVDE) concentration, and between in vivo metabolizability of GE (ME/GE) and in vitro digestibility of GE (IVDE/GE), respectively. In a validation experiment, 6 sources of corn with previously published ME concentration in 2008 randomly selected from the primary corn-growing regions of China were used to validate the prediction models established in the calibration experiment. The results showed that in calibration samples, the IVDE concentration was positively correlated with the AME (r = 0.9419), AMEn (r = 0.9480), TME (r = 0.9403), and TMEn concentration (r = 0.9473). Similarly, the IVDE/GE was positively correlated with the AME/GE (r = 0.95987), AMEn/GE (r = 0.9641), TME/GE (r = 0.9588), and TMEn/GE (r = 0.9637). The coefficient of determination greater than 0.88 and 0.91, and residual SD less than 45 kcal/kg of DM and 1.01% were observed in the prediction models for ME concentrations and ME/GE, respectively. Twenty-nine out of 30 calibration samples showed differences less than 100 kcal/kg of DM and 2.4% between determined and predicted values for 4 ME (AME, AMEn, TME, and TMEn) and for 4 ME/GE (AME/GE, AMEn/GE, TME/GE, and TMEn/GE), respectively. Using prediction models developed from 30 calibration samples, 6 validation samples further showed differences less than 100 kcal/kg of DM and 2% between determined and predicted values for ME and ME/GE, respectively. Therefore, the computer-controlled simulated digestion system can be used to predict the ME and ME/GE of corn for ducks with acceptable accuracy.

Threonine requirement of White Pekin ducks from hatch to 21 d of age.

1. A dose-response experiment with 5 dietary threonine concentrations (5.0, 5.8, 6.6, 7.4 and 8.2 g/kg) was conducted to estimate the threonine requirement of White Pekin ducks from hatch to 21 d of age. 2. A total of 240 one-d-old male White Pekin ducks were allotted to 5 experimental treatments and each treatment contained 6 replicate pens with 8 ducks per pen. Ducks were reared in raised wire-floor pens from hatch to 21 d of age. At 21 d of age, growth performance and intestinal morphology were determined. 3. The weight gain and feed intake of Pekin ducks increased and feed/gain of these birds decreased linearly or quadratically as dietary threonine increased from 5.0 to 8.2 g threonine/kg. Compared to ducks fed on diets containing 5.0 g threonine/kg, ducks given diets containing 7.4 g threonine/kg had higher villus height in duodenum, jejunum and ileum. 4. The threonine requirements for weight gain of White Pekin ducks from hatch to 21 d of age was estimated to be 6.72 g/kg when dietary crude protein concentration was 189.8 g/kg and threonine supply was critical for maintaining intestinal structure of these birds.

Choline requirements of male White Pekin ducks from 21 to 42 d of age.

1. A dose-response experiment with 6 dietary choline concentrations (0, 342, 779, 1285, 1662 and 1962 mg/kg) was conducted with male White Pekin ducks to estimate the choline requirement from 21 to 42 d of age. 2. Ninety 21-d-old male White Pekin ducks were allotted to 6 dietary treatments, each containing 5 replicate pens with three birds per pen. At 42 d of age, final weight, weight gain, feed intake and feed/gain were measured. Liver was collected to determine total liver lipid, triglyceride and phospholipids. 3. Significant positive effects of dietary choline on final weight, weight gain and feed intake were observed. In addition, dietary choline supplementation significantly decreased liver lipid and triglyceride content and increased liver phospholipids of Pekin ducks. 4. According to broken-line regression analysis, the choline requirements of male White Pekin ducks from 21 to 42 d of age for weight gain, feed intake and total liver lipid were 980, 950 and 1130 mg/kg. Pekin ducks needed more choline to prevent excess liver lipid deposition than to maintain growth.