The association between per-/polyfluoroalkyl substances in serum and thyroid function parameters: A cross-sectional study on teenagers living near a Chinese fluorochemical industrial plant

Thyroid hormones (THs) play an important role in a wide range of crucial biological functions related to growth and development, and thyroid antibodies (TAs) can influence the biosynthesis of THs. Epidemiological studies have indicated that per- and polyfluoroalkyl substances (PFAS) could induce thyroid disruption, but studies on teenagers living in areas with high PFAS exposure are limited. This cross-sectional study focused on 836 teenagers (11- 15 years) living near a Chinese fluorochemical industrial plant. Decreased levels of free thyroxine (FT4, ﹤9.6 pmol/L, abnormal rate = 19.0 %) and elevated levels of free triiodothyronine (FT3, ﹥6.15 pmol/L, abnormal rate = 29.8 %) were observed. Correlations of serum PFAS concentrations and TAs/THs were analyzed. Increased PFOA was identified as a risk factor of decreased FT4 by using unadjusted (OR: 11.346; 95 % CI: 6.029, 21.352, p < 0.001) and adjusted (OR: 12.566; 95 % CI: 6.549, 24.115, p < 0.001) logistic regression models. In addition, significantly negative correlations were found between log10 transformed PFOA and FT4 levels using linear (unadjusted: β = -1.543, 95 % CI: -1.937, -1.148, p < 0.001; adjusted: β = -1.534, 95 % CI: -1.930, -1.137, p < 0.001) and BKMR models. For abnormal FT3, a significantly positive association between PFHxS and FT3 levels was observed in a regression model (unadjusted: β = -0.903, 95 % CI: -1.212, -0.595, p < 0.001; adjusted: β = -0.894, 95 % CI: -1.204, -0.583, p < 0.001), and PFHxS was identified as a risk factor (unadjusted: OR: 4.387; 95 % CI: 2.619, 7.346, p < 0.001; adjusted: OR: 4.527; 95 % CI: 2.665, 7.688, p < 0.001). Sensitivity analyses confirmed the robustness of the above results. This study reported the elevated PFAS exposure and thyroid function of teenagers living near a fluorochemical industrial plant from China.

[Association between sedentary behavior and force expiratory volume in 1 second reduction in middle-aged and elderly adults in communities]

Objective: To analyze the relationship between sedentary behavior and the force expiratory volume in 1 second (FEV₁) reduction in middle-aged and elderly people in communities. Methods: The participants aged ≥40 years were randomly selected from a natural population cohort in Songjiang District, Shanghai, for pulmonary function tests and survey by using international physical activity questionnaire, a generalized additive model was used to analyze the association between sedentary behavior and FEV₁ reduction in the study population and different sex-age subgroups. Results: A total of 3 121 study subjects aged ≥40 years were included. The prevalence of FEV₁ reduction was 14.8%, which was higher in men than in women. There were 24.8% participants were completely sedentary. The prevalence of FEV₁ reduction in women aged <60 years in complete sedentary group was 2.04 (95%CI: 1.11-3.72) times higher than that in non-complete sedentary group. In men aged <60 years, the prevalence of FEV₁ reduction increased with daily sedentary time (OR=1.16, 95%CI: 1.04-1.29), and the prevalence of FEV₁ reduction was also higher in those with sedentary time >5 hours/day than those with sedentary time ≤5 hours/day (OR=3.02, 95%CI: 1.28-7.16). The sensitivity analysis also found such associations. Conclusions: FEV₁ reduction rate in age group <60 years was associated with sedentary behavior. Complete sedentary behavior or absence of moderate to vigorous physical activity played important roles in FEV₁ reduction in women, while men were more likely to be affected by increased sedentary time, which had no association with physical activity. Reducing sedentary time to avoid complete sedentary behavior, along with increased physical activity, should be encouraged in middle-aged and elderly adults in communities to improve their pulmonary function.

[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.

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 cecum 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 acetic acid, propionic acid, and butyric acid in the cecum (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.

[Disease burden of chronic obstructive pulmonary diseases in China from 1990 to 2019]

Objective: To examine the trend of the burden on chronic obstructive pulmonary diseases (COPD) and epidemiologic transition on related risk factors among the Chinese population from 1990 to 2019. Methods: Based on the data from the Global Burden of Disease 2019 Study, we used the indicator numbers such as disability-adjusted life year (DALY), years of life lost (YLD), years lived with disability (YLL), and prevalence rate to describe the changes of COPD burden stratified by different sex and age groups from 1990 to 2019. We applied population attribution faction (PAF) to analyze the burden attributed to risk factors and epidemiological transition. Results: In 2019, the age-standard rate for DALY, YLD, and YLL and prevalence rate for COPD were 1 102.77/100 000 population,862.37/100 000 population, 240.40/100 000 population, and 2 404.41/100 000. Both age-standardized DALY and YLL rates for COPD in males were higher than in females, except for the YLD rate in females. COPD's top five risk factors were particulate matter pollution, smoking, occupational particulate matter, gases, and fumes, low temperature, and secondhand smoke. Smoking surpassed environmental particulate pollution in 1994 and became the first factor causing the disease burden of COPD. Since then, the order of risk factors has not changed. The PAF of environmental particulate pollutants increased by 1.78% annually, from 15.22% in 1990 to 25.37%, and the PAF of household air pollution from solid fuels decreased by 5.59% annually, from 40.30% in 1990 to 7.59%. Conclusions: From 1990 to 2019, the per person health loss caused by COPD in China showed an overall downward trend. The PAF of relevant risk factors has also changed, the importance of environmental factors is relatively declined, and the status of smoking and other related risk behaviors has become increasingly prominent. The prevention and control of COPD can focus on screening high-risk groups (≥40 years old, smoking, heavy air pollution, having occupational exposure), smoking cessation, and environmental treatment.

[Association of BMI with acute exacerbation in mild to moderate chronic obstructive pulmonary disease patients in community: a prospective study]

Objective: BMI may play a protective role in reducing the mortality rate of patients with chronic obstructive pulmonary disease (COPD), but its effect on acute exacerbation of COPD remain unclear. Methods: Subjects were selected from the COPD patients registration system established in 2014 in Pudong new district, Shanghai. COPD patients from 8 communities were selected by cluster sampling and follow up was conducted prospectively for 18 months. Basic information and BMI were obtained from baseline survey, and acute exacerbations were collected during follow-up. The association between BMI and risk of acute exacerbation was evaluated by using multiple negative binomial regression. Results: Among 328 community COPD patients, 295 who completed the follow up were included in the analysis, in whom 96.3% (284/295) were mild COPD patients. During the follow-up, 11.1% (33/295) of the patients reported acute exacerbation. The results of multiple negative binomial regression suggested that, the risk for acute exacerbation decreased with the increase of BMI (IRR=0.85, 95%CI:0.73-0.98), overweight patients with BMI ≥25.0 kg/m² (IRR=0.36, 95%CI:0.13-0.91) or moderate BMI (T₂ vs. T₁, IRR=0.31, 95%CI:0.11-0.77) had lower risk for acute exacerbation compared with the patients with normal or low BMI. BMI had a linear correlation with the risk of acute exacerbation. Conclusion: The risk for acute exacerbation in patients with mild or moderate COPD in communities decreased with the increase of BMI, and being overweight might be a protective factor for the acute exacerbation of COPD.

Serum concentrations of per-/polyfluoroalkyl substances and its association with renal function parameters among teenagers near a Chinese fluorochemical industrial plant: A cross-sectional study

Currently, studies on the association between per-/polyfluoroalkyl substances (PFAS) concentrations and the renal function of residents, especially teenagers, living near fluorochemical industrial plants, are relatively rare, and not all these studies suggested associations. In this cross-sectional study, 775 local teenagers (11-15 years old) were included, and serum concentrations of 18 PFAS were measured. Perfluorooctanoic acid (PFOA) was found to be the dominant PFAS with a concentration of 22.3-3310 ng/mL (mean = 191 ng/mL), accounting for 71.5-99.1% of ΣPFAS. Statistical analyses demonstrated that internal exposure of perfluoroalkyl carboxylic acids (PFCA, C8-C10) was related to the plant. In addition, the prevalence rate of chronic kidney disease (CKD) (35.0%) in the participants was relatively high. A significantly positive association was observed between the increase in PFOA concentration and increasing risk of CKD (OR = 1.741; 95% CI: 1.004, 3.088; p = 0.048) by adjusting for gender, age, body mass index (BMI), and household income. Similar positive correlation was also observed in PFHpA with CKD (OR = 1.628, 95% CI: 1.031, 2.572; p = 0.037). However, no significant correlation was observed for concentrations of other PFAS and CKD (p > 0.05). Furthermore, linear regression analyses demonstrated that none of the PFAS concentrations were significantly correlated with estimated glomerular filtration rate (eGFR) or urine albumin/urine creatinine ratio (ACR) (p > 0.05). However, a significantly negative correlation was observed between PFOA concentration and abnormal ACR (β = -0.141, 95% CI: -0.283, 0.001; p = 0.048) after stratifying by CKD. Sensitivity analyses further confirmed these results. This cross-sectional study is the first, to our knowledge, to investigate the association between PFAS concentrations and renal function in teenagers living near a Chinese industrial plant. Further prospective and metabonomic studies are needed to interpret the results and clarify the biological mechanisms underlying this association.

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.

Concentration, spatial distribution, and health risk assessment of PFASs in serum of teenagers, tap water and soil near a Chinese fluorochemical industrial plant

Discharges released from fluorochemical industrial plants lead to severe contamination of the environment with per- and polyfluoroalkyl substances (PFASs), which may pose risks to human health. In this study, 187 serum samples from teenagers (age = 14 years), 22 tap water samples and 40 soil samples were collected in areas within 0-11 km of a fluorochemical industrial plant in Huantai County, Shandong Province, and concentrations of 18 PFASs were quantified by UPLC-MS/MS. Perfluorooctanoic acid (PFOA) was found to be predominant, concentrations of which ranged from 40.4 to 845 ng/mL in serum, from 2.88 to 19.3 ng/L in tap water, from 4.40 to 189 ng/g in soil, and accounting for 84.1-98.6%, 15.9-79.8%, and 73.8-96.7% of the total PFASs, respectively. Statistical analysis demonstrated that concentrations of perfluorinated carboxylic acids (PFCAs) in soil (C5-C9) and serum (C8-C10) were associated with the industrial plant. And PFOA concentrations in tap water were not relevant to the industrial plant, which were comparable with the non-contaminated area and lower than the threshold value recommended by U.S. EPA (70 ng/mL), indicating that the contribution to the high concentration of serum PFOA of local teenagers by drinking water was limited. Moreover, PFCAs in soil only made a limited contribution to the serum PFCAs of local residents by direct inhalation and dermal exposure, but the potential health risk by the soil via food chain should be paid attention to. Furthermore, health risk assessment demonstrated that high concentrations of PFOA in serum could pose potential health risk to local teenagers. Therefore, effective measures should be taken to attenuate the health risks caused by the industrial plant to local residents, and further epidemiological studies should be carried out in the future.

[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.

The feasibility of enzyme hydrolysate gross energy for formulating duck feeds

Two experiments were designed to investigate the feasibility of enzyme hydrolysate gross energy (EHGE) for formulating duck feeds. In experiment 1, six mixed diets and 6 experimental diets (compound feeds) with 20% CP were formulated, and their EHGE, AME, and TME were determined so as to analyze the correlation between EHGE and AME, TME. In experiment 2, six experimental diets with different EHGE levels were further arranged to determine the EHGE requirement for Pekin ducks from hatch to 21 D of age. A total of 384 freshly hatched ducklings was randomly divided into 6 experimental treatments, each treatment containing 8 replicates with 8 ducks per replicate. The results showed that there were a linear correlation between EHGE and AME (r = 0.998, P < 0.01), TME (r = 0.997, P < 0.01) for 6 mixed diets, and the regression models were AME = 0.996 × EHGE−1.062 (R² = 0.996, P < 0.01), TME = 0.997 × EHGE+0.304 (R² = 0.995, P < 0.01). For the 6 experimental diets, EHGE was also positively correlated with AME (r = 0.983, P < 0.01), TME (r = 0.984, P < 0.01), and the regression models were AME = 1.2054 × EHGE−3.180 (R² = 0.967, P < 0.01), TME = 1.2054 × EHGE−1.783 (R² = 0.967, P < 0.01). According to the broken-line model and optimal BW, the EHGE requirement for ducks from hatch to 21 D of age was 2,937 kcal/kg (calculated value), 3,182 kcal/kg (determined value). In conclusion, EHGE could be used to predict the AME and TME values for mixed diets and compound feeds based on established regression models, and the simulated digestion method in vitro has the potential for effective energy evaluation and formulation for duck feeds.

Research Note: Effects of riboflavin on reproductive performance and antioxidant status of duck breeders

An experiment was conducted to investigate the effects of dietary riboflavin levels on reproductive performance, riboflavin status, and antioxidant status of laying duck breeders, to estimate the requirement of this vitamin for duck breeders. Different levels crystalline riboflavin (0, 2.5, 5, 10, and 15 mg/kg) were supplemented to a corn-soybean-corn gluten meal basal diet to produce 5 dietary treatments with different analyzed total riboflavin levels (1.48, 3.20, 6.30, 11.71, and 16.83 mg/kg). A total of 80 White Pekin duck breeders aged 40 wk were allotted to 5 dietary treatments of 16 birds each (8 replicates per treatment and 2 breeders per replicate), and all birds were raised individually for 9 wk. At the end of the experiment, reproductive performance, tissue riboflavin concentrations, and antioxidant status of White Pekin duck breeders were measured. The results showed that body weight, egg weight, egg production, and egg fertility were not affected by dietary riboflavin levels. However, among all of the laying duck breeders, the birds fed the basal diet without riboflavin supplementation had the lowest egg hatchability, plasma riboflavin, egg yolk riboflavin, and egg albumen riboflavin (P < 0.001). In addition, the duck breeders fed the basal diet without riboflavin supplementation showed the lowest antioxidant capacity indicated by greatest plasma malondialdehyde (MDA) content and lowest reduced glutathione content, total superoxide dismutase (T-SOD) activities, and total antioxidant capacity in both plasma (P < 0.001) and egg yolk (P < 0.001). These results revealed that dietary riboflavin supplementation improved the reproductive performance and antioxidant status of the duck breeders. According to the broken-line model, the riboflavin requirements (based on dietary total riboflavin) of laying duck breeders in terms of the egg hatchability, plasma riboflavin, egg yolk riboflavin, egg albumen riboflavin, plasma T-SOD activity, and plasma MDA content were 3.19, 7.42, 3.88, 7.44, 6.45, and 8.84 mg/kg, respectively.

Effects of dietary energy and methionine on growth performance and carcass traits of growing Pekin ducks from 15 to 42 days of age

A 2 × 5 factorial experiment, using 2 dietary metabolizable energy (ME) levels (10.82, 12.95 MJ/kg) and 5 supplemental methionine (Met) levels (0, 0.075, 0.15, 0.225, and 0.30%), was conducted to investigate the effects of dietary energy and Met levels on growth performance and carcass traits of Pekin ducks from 15 to 42 D of age. A total of 300 15-day-old male Pekin ducks were randomly allocated to 10 groups with 6 replicates in each group and 5 ducks per replicate. The results showed that ducks those fed the basal diets without Met supplementation had poor growth performance. The ADG was increased (P < 0.001), and the ADFI and feed conversion ratio (FCR) decreased (P < 0.001) when Met were supplemented in diets. The ADFI and FCR were decreased (P < 0.001), while ADG was not affected (P > 0.05) when dietary ME level increased from 10.82 to 12.95 MJ/kg. Dietary Met supplementation increased the yields of eviscerated carcass (P = 0.007) and breast meat (P < 0.001), and decreased abdominal fat (P < 0.001), but increasing dietary energy level resulted in an adverse effect on carcass traits. We observed an interaction effect on FCR between dietary energy and supplemental Met level (P = 0.033). According to the broken-line models, Met requirements of growing Pekin ducks for optimal FCR at 10.82 and 12.95 MJ/kg of ME were 0.406 and 0.502% when expressed as percentage of diet, or 0.376 and 0.388 when expressed as g/MJ ME of diet, respectively. According to the t-test, Met requirements were different (P < 0.05) when expressed as percentage of diet, but had no difference (P > 0.05) when expressed as g/MJ ME of diet in both dietary ME levels. It indicated that Met requirement was affected by dietary ME level, but the Met/ME ratio was relatively constant in diet of Pekin ducks from 15 to 42 D of age.

Effects of post-hatch brooding temperature on performance of starter and growing Pekin ducks

An experiment was conducted to investigate the effects of post-hatch brooding temperature on the growth performance of starter Pekin ducks from hatch to 14 D of age and the subsequent growth performance and carcass trait of growing ducks from 15 to 42 D of age. A total of 360 one-day-old male White Pekin ducks were allocated randomly to 6 environment-controlled chambers with ambient temperature set at 26, 28, 30, 32, 34, and 36°C from hatch to 7 D of age, respectively, and then decreased gradually to 26°C at 14 D of age. At 14 D of age, all ducks from all chambers were transferred to a duck barn with ambient temperature maintaining from 26 to 22°C and these birds continued to be raised from 14 to 42 D of age. At 14 D of age, body weight, weight gain, and feed intake decreased linearly or quadratically as initial brooding temperature increased (P < 0.05) and these performance traits were reduced when initial brooding temperature increased to 36°C (P < 0.05). There was no difference in growth performance between ducks fed at brooding temperature regimen starting at 26, 28, 30, and 32°C (P > 0.05). According to broken-line regression, the upper critical temperatures of the initial brooding temperature during the starter period for body weight, weight gain, and feed intake were 31.3, 31.3, and 31.1°C, respectively. On the other hand, the growing ducks brooded initially at 26 or 36°C had lower body weight, weight gain, and feed intake as compared to other birds brooded starting from 28 to 34°C (P < 0.05), but the initial brooding temperature had no effects on carcass traits (P > 0.05). It was concluded that the upper critical temperature of the initial brooding temperature for starter Pekin ducks was 31.3°C and too low initial brooding temperature could lead to growth depression during the subsequent growing period.

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.

Effects of vitamin A on growth performance and tissue retinol of starter White Pekin ducks

A dose-response experiment with 8 supplemental vitamin A levels (0, 500, 1,000, 1,500, 2,500, 3,500, 7,000, and 14,000 IU/kg) were conducted to examine the effects of vitamin A on growth performance and tissue retinol of starter White Pekin ducks. A total of 512 one-day-old male Pekin ducks were randomly divided into 8 treatments and each treatment contained 8 replicate pens of 8 ducks. All these ducks were reared in raised wire-floor pens from hatch to 21 D of age. At 21 D of age, growth performance and retinol concentration in plasma and liver were measured. Among all ducks, the birds fed basal diet with no supplemental vitamin A had the lowest weight gain, feed intake, and plasma and liver retinol (P < 0.05). As supplemental vitamin A increased, weight gain and feed intake increased quadratically (P < 0.05) and plasma and liver retinol increased linearly or quadratically (P < 0.05). The weight gain and plasma retinol showed broken-line response to increasing supplemental vitamin A (P < 0.05). According to broken-line regression, the minimum supplemental vitamin A requirements for weight gain and plasma retinol were 2606 and 4371 IU/kg, respectively. It was concluded that vitamin A deficiency could lead to a reduction in growth performance and tissue retinol retention and plasma or liver retinol was available biomarker to assess duck vitamin A status.

Dual functions of eicosapentaenoic acid-rich microalgae: enrichment of yolk with n-3 polyunsaturated fatty acids and partial replacement for soybean meal in diet of laying hens

Microalgae (Nannochloropsis sp., NS), with high contents of eicosapentaenoic acid (EPA) and crude protein, may be one of the important n-3 polyunsaturated fatty acid (PUFA) sources and potential protein feed ingredient. The purposes of this study were to enrich yolk with n-3 PUFA by dietary EPA-rich NS supplementation and to evaluate whether it is feasible to partly substitute for soybean meal in laying hens diet. A total of 360 37-wk-old healthy Lohmann Brown laying hens, with similar laying rate and body weight, were randomly allotted to 5 groups (6 replicates, 12 birds/replicate) and fed 5 experimental diets (0, 1, 2, 4, and 8% NS) for 4 wk. The hen performance and egg quality (except yolk color) were not affected (P > 0.05) by the NS supplemental diets. Yolk color score was increased as NS supplementation in diets (P < 0.001), and peaked on about the seventh day in all NS supplemental groups. The concentration of total n-3 PUFA was increased (P < 0.001), while total n-6 PUFA and n-6/n-3 ratio were decreased (P < 0.001) in yolk with increasing NS levels in diets. The 8% NS group had highest docosahexaenoic acid (DHA) and total n-3 PUFA levels, reaching 111.6 mg DHA and 148.6 mg total n-3 PUFA per egg. Maximum DHA, total n-3 PUFA, very long-chain (LC-) n-3 PUFA, and LC-PUFA levels were all observed at day 13 of NS supplementation. In conclusion, dietary NS supplementation enriched yolk with n-3 PUFA (especially DHA) and enhanced yolk color score without adverse effects on performance and egg quality, and indicated the practical feasibility of partial replacement for soybean meal in laying hens diet.

Interactions of dietary protein and threonine on growth performance in Pekin ducklings from 1 to 14 days of age

The present study was conducted to investigate the effects of dietary crude protein (CP) on threonine requirements by determining the interactions of dietary CP levels (16.0, 17.5, 19.0, 20.5, and 22.0%) and supplemental threonine levels (0, 0.07, 0.14, 0.21, and 0.28%) on growth performance of Pekin ducks from 1 to 14 days of age. A total of 1,200 one-day-old male Pekin ducks was randomly allotted to 1 of 25 dietary treatments with 6 replicate pens of 8 birds per pen for each treatment. The results showed that dietary CP and threonine levels affected the average daily feed intake (ADFI, P < 0.0001), average daily gain (ADG, P < 0.0001), ratio of feed/gain (F/G, P < 0.0001) of Pekin ducks, and had an interactions on the ADFI, ADG, F/G (P < 0.0001). The ADG was increased linearly (P < 0.002) and then reached a plateau as the dietary threonine increased at all CP diets. According to the estimation of broken-line models, the dietary threonine requirements at 16.0, 17.5, 19.0, 20.5, and 22.0% CP diets for optimal ADG of ducks were 0.56, 0.61, 0.60, 0.63, and 0.67% when expressed as percentage of diet, or 44.22, 47.65, 47.50, 48.30, and 50.39% when expressed as percentage of dietary lysine, or 3.45, 3.44, 3.12, 3.27, and 2.98% when expressed as percentage of dietary CP, respectively. Threonine requirements of Pekin ducks from 1 to 14 days of age were affected by dietary CP levels according to the Student t test results, but had no difference among the moderate CP level diets (17.5, 19, and 20.5%) when expressed as a percentage of diet or dietary lysine. It was concluded that dietary CP levels affected the threonine requirements of Pekin ducks from 1 to 14 days of age, but threonine requirements were constant within the limiting CP level range (17.5 to 20.5%) with a good balance of dietary amino acid, and were approximately 0.60 to 0.63% of diet or 47.5 to 48.3% of dietary lysine.

Effects of low-protein diets on growth performance and carcass yield of growing White Pekin ducks

A dose-response experiment with 6 analyzed dietary crude protein (CP) levels (13.54, 14.37, 14.71, 16.04, 16.61, and 17.22%) was conducted to investigate the effects of low-protein diets on growth performance and carcass yield of growing White Pekin ducks from 14 to 35 d of age. All diets were formulated to contain a similar dietary energy level and the standardized ileal digestible amino acid profile including lysine, methionine, threonine, tryptophan, arginine, isoleucine, valine, and glycine. A total of 288 14-day-old male White Pekin ducks were divided into 6 experimental treatments and each treatment contained 8 replicate pens of 6 birds. Ducks were raised in wire-floor pens from 14 to 35 d of age. At 35 d of age, the weight gain, feed intake, feed/gain, and the yield of carcass, breast meat, leg meat, and abdominal fat of ducks from each pen were measured. As dietary CP decreased from 17.22 to 13.54%, weight gain and feed intake were not affected (P > 0.05) but feed/gain increased when dietary CP decreased to 13.54% (P < 0.05). On the other hand, the yield of carcass, leg meat, and breast meat was not influenced by reducing dietary CP (P > 0.05) but the abdominal fat increased when dietary CP was 13.54% (P < 0.05). Based on broken-line regression, the 14.81 and 14.94% were the minimum dietary CP to keep the feed/gain and abdominal fat similar to the ducks fed with 17.22% CP diets, respectively. In summary, with crystalline amino acid supplementation based on a similar standardized ileal digestible amino acid profile, it was possible to formulate the low-protein diets containing about 15% CP for Pekin ducks without adverse effects on their growth performance and carcass yield.

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.

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.

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.

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 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.

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.

Developmental characteristics of pectoralis muscle in Pekin duck embryos

To confirm the entire developmental process and transition point of embryonic Pekin duck pectoral muscle, and to investigate the association between pectoral muscle development and their regulating genes, anatomical and morphological analyses of embryonic Pekin duck skeletal muscles were performed, and the expression patterns of its regulating genes were investigated. The anatomical analysis revealed that body weight increased with age, while increases in pectoral muscle weight nearly ceased after the embryo was 20 days of hatching (E20). The developmental morphological characteristics of Pekin duck pectoral muscle at the embryonic stage showed that E20 was the transition point (from proliferation to fusion) of Pekin duck pectoral muscle. The expression patterns of MRF4, MyoG, and MSTN indicated that E19 or E20 was the fastest point of pectoral muscle development and the crucial transition for Pekin duck pectoral muscle development during the embryonic stage. Together, these findings imply that E20 is the crucial transition point (from proliferation to fusion) of Pekin duck pectoral muscle and that there is no muscle fiber hypertrophy after E20. Results of this study provide further understanding of the developmental process and transition point of Pekin duck pectoral muscle during the embryo stage.

Effects of biotin on growth performance and foot pad dermatitis of starter White Pekin ducklings

1. An experiment with 9 dietary supplemental biotin concentrations (0, 0.03, 0.06, 0.09, 0.12, 0.15, 0.18, 0.21, 1.5 mg biotin/kg) was conducted to study the effects of supplementary dietary biotin on growth performance and foot pad dermatitis (FPD) of White Pekin ducklings from hatch to 21 d of age. 2. One-d-old male Pekin ducklings (n=576) were randomly divided into 9 dietary treatments, each containing 8 replicate pens with 8 birds per pen. Final weight, feed intake and body weight gain increased with increasing dietary biotin levels from hatch to 21 d of age. No differences were observed in feed conversion ratio. 3. The supplemental biotin requirement of ducklings for optimal body weight gain was estimated to be 0.180 mg/kg. 4. At 28 d of age, dehydration, cracks, bleeding and scab, and ulceration were observed in biotin-deficient ducks. The external scores for FPD decreased from 17.50 to 1.00 with increasing dietary biotin. It was concluded that supplemental dietary biotin should not be less than 0.21 mg/kg to minimise the incidence of FPD.

Molecular cloning of the perilipin gene and its association with carcass and fat traits in Chinese ducks

The perilipin (PLIN) gene is a candidate gene of carcass and fat traits in ducks. In order to study the molecular character of the PLIN gene and its function in different breeds of Chinese ducks, samples were obtained from the Chinese Academy of Agricultural Sciences Research Center for Birds, including 95 Peking ducks of the Z2 series, 91 Peking ducks of the Z4 series, 82 hybrid systems (Z2 x Z4), and 93 Cherry Valley ducks. We used RT-PCR and 3'-RACE to clone the duck PLIN gene, detect SNPs and analyze their associations with carcass and fat traits. A 2212-bp sequence was cloned with the complete coding region and a 3'-untranslated region. We found a nucleotide mutation (C → T) in exon 2 of the PLIN gene. There were no significant correlations between the 3 genotypes (CC, CT, TT) in breast muscle weight (BMW), leg muscle weight (LMW), subcutaneous fat weight (SFW), and intramuscular fat (IMF) in the Cherry Valley duck. The CC and CT genotypes had significant differences in carcass weight (CW), carcass net weight (CNW), and percentage of abdominal fat weight (AFW); there were significant differences in AFW and percentage of SFW. In Z4, there were no significant correlations between the 3 genotypes (TT, CC, and CT) in CW, BMW, LMW, SFW, AFW, the percentage of SFW and AFW, and IMF. CNW was significantly different between TT, CC, and CT genotypes. In Z2 x Z4, there were no significant correlations between the 3 genotypes in CW, BMW, LMW, SFW, AFW, the percentage of SFW and AFW, and IMF, while the CC and CT genotypes had significant differences in CNW. In Z2, there were no significant differences between the 3 genotypes in all traits. We deduced that the PLIN gene is a potential major gene. It is linked to a major gene affecting meat quality traits. This SNP has potential as a molecular marker for marker-assisted selection.

Riboflavin requirements of white Pekin ducks from hatch to 21 d of age

1. A 2 × 8 factorial experiment containing different sexes (female and male) and 8 dietary riboflavin concentrations (1.2, 3.2, 5.2, 7.2, 9.2, 11.2, 13.2 and 15.2 mg/kg) was conducted to evaluate the riboflavin requirements of male and female White Pekin ducks from hatch to 21 d of age. 2. A total of 640 1-d-old Pekin ducks including 320 male and 320 female birds were randomly distributed into 80 wire-floor pens of 8 birds, sexed separately and with each treatment group containing 5 replicate pens. The birds were raised from hatch to 21 d of age. At 21 d of age, the weight gain, feed intake, feed conversion ratio and plasma and liver riboflavin were measured. 3. Growth depression, high mortality and low plasma and liver riboflavin were observed in riboflavin-deficient ducks, and these ill effects could be reduced by increasing dietary riboflavin concentrations. Weight gain, feed intake and riboflavin concentration in plasma and liver increased as dietary riboflavin increased. 4. According to broken-line regression analysis, the riboflavin requirements of modern breed of White Pekin ducks from hatch to 21 d of age for weight gain, feed conversion ratio, plasma riboflavin and liver riboflavin were 3.31, 5.20, 3.85 and 3.91 mg/kg for male and 3.27, 3.33, 3.84 and 3.28 mg/kg for female, respectively. Compared with female birds, more riboflavin was needed by male ducks, which may be because of significantly greater weight gain and liver riboflavin content of male ducks.

Characterization of myostatin gene (MSTN) of Pekin duck and the association of its polymorphism with breast muscle traits

Myostatin, encoded by the MSTN gene, is a negative regulator of muscle growth, and its expression level in muscle tissue is closely correlated with muscle growth and satellite cell proliferation. To identify the characteristics of the Pekin duck MSTN gene and the relationship between its polymorphism and breast muscle traits in Pekin duck, cDNA cloning and analysis and the expression pattern in breast muscle development and polymorphism were performed using molecular cloning, quantitative real-time reverse-transcription polymerase chain reaction, and molecular marker technology. The results showed that a 1320-bp sequence, including a 93-bp 5'-UTR, 1128-bp CDS, and 99- bp 3'-UTR, was obtained, and two alternative splicing isoforms were detected. The alternative splicing isoforms encoded 375- and 251-amino acid residues. The amino acid sequence of Pekin duck MSTN was similar to other vertebrates and exhibited the highest similarity to chicken. The expression pattern of MSTN in breast muscle tissue showed a tendency to increase, except for a slight decrease at 6 weeks. Three single nucleotide polymorphisms were found in the Pekin duck MSTN gene by cDNA sequencing from different individuals. The T129C had significant association with breast muscle thickness, and the T952C had significant association with the fossilia ossis mastodi length. This study reveals the molecular characteristics of the Pekin duck MSTN gene and the relationship of its polymorphism with breast muscle traits in Pekin duck. Therefore, it can provide some useful basic understanding of MSTN functions.

[Model of regularity of ammonia transformation along marine biological aerated filter]

This study investigates the biological aerated filter (BAF) of a marine recirculating aquaculture system, which is important to remove harmful ammonia and organics. A model, characterizing the ammonia transformation along the BAF, was established on the basis of the principle of adsorption and the first order reaction bio-film. Experiments were performed and verified the effectiveness of the proposed model. The target BAF was packed with bamboo ring for 70 cm high. Study under the conditions [pH 7.1-7.6, DO 5-7 mg x L(-1), gas water ratio about 20 : 1, organic load about 4 g x (m3 x h)(-1)] shows that ammonia is removed significantly under the 10 cm height of medium, while less ammonia is removed between 10-70 cm. Experimental results confirm that the model predicts the ammonia concentration along the BAF accurately with a low influent ammonia concentration, but the predicted value is slightly lower than the true value with a high influent ammonia concentration. Study on ammonia concentration along the BAF reveals that the effluent ammonia concentration increases along with either the increment of the influent ammonia concentration or the reduction of the hydraulic retention time.

Fabrication and characterization of bioactive composite coatings on Mg-Zn-Ca alloy by MAO/sol-gel

High corrosion rate and accumulation of hydrogen gas upon degradation impede magnesium alloys' clinical application as implants. In this work, micro-arc oxidation (MAO) was used to fabricate a porous coating on magnesium alloys as an intermediate layer to enhance the bonding strength of propolis layer. Then the composite coatings were fabricated using sol-gel method by dipping sample into the solution containing propolis and polylactic acid at 40 °C. The corrosion resistance of the samples was determined based on potentiodynamic polarization experiments and immersion tests. Biocompatibility was designed by observing the attachment and growth of wharton's jelly-derived mesenchymal stem cells (WJCs) on substrates with MAO coating and substrates with composite coatings. The results showed that, compared with that of Mg-Zn-Ca alloy, the corrosion current density of the samples with composite coatings decreased from 5.37 × 10⁻⁵ to 1.10 × 10⁻⁶ A/cm² and the corrosion potential increased by 240 mV. Composite coatings exhibit homogeneous corrosion behavior and can promote WJCs cell adhesion and proliferation. In the meantime, pH value was relatively stable during the immersion tests, which may be significant for cellular survival. In conclusion, our results indicate that composite coatings on Mg-Zn-Ca alloy fabricated by MAO/sol-gel method provide a new type bioactive material.

Molecular analysis of the coat protein gene of peanut stripe virus from China

Peanut stripe virus (PStV) is one of the most common viruses infecting peanut that causes great economic losses every year. The 3ʹ-terminal 1082 bp of 74 PStV isolates collected from 12 districts of Shandong province, China were sequenced. Their coat protein (CP) genes were 864 bp in length and shared identities of 98.0%~100% and 98.3% ~100% at nt and aa levels. The identities between the CP genes of these isolates and other 36 isolates from the GenBank were 93.5%~100% and 92.0%~100% at nt and aa levels, respectively. PStV isolates can be clustered into two phylogenetic groups. The isolates from United States, mainland China, and Indonesia formed group I and those from Viet Nam, Thailand, and Taiwan formed group II. The PStV isolates in group I can be further classified to two subgroups. The gene flow of PStV populations within a country was frequent, but that between countries was infrequent.

Molecular variability of five Cucumber mosaic virus isolates from China

Cucumber mosaic virus (CMV) isolates are currently divided into two main groups, I and II according to their genomic sequences. The group I is further divided into two subgroups IA and IB. We performed a phylogenetic analysis of the genome regions containing 1a, 2a, 2b, coat protein (CP), and movement protein (MP) genes of 5 CMV isolates from China and other 28 CMV isolates available in the GenBank. The results indicated that CMV isolates could be genetically divided into three groups I, II, and III according to the genes encoding MP, CP, 1a, and 2a proteins and to the 2 groups according to the gene 2b. Group I could be further divided into two subgroups (IA and IB) according to the genes encoding CP, MP, 2a, and 2b proteins and to the three subgroups (IA, IB, and IC) according to the gene encoding 1a protein. Four of 5 examined Chinese CMV isolates belonged to the subgroup IB, while the remaining isolate was a natural inter-subgroup reassortant. We found that the 2b gene of CMV was under positive selection, while the other genes were under negative selection. No evidence of the selection associated with a host adaptation or geographic distribution was found.

Predicting metabolizable energy of normal corn from its chemical composition in adult Pekin ducks

Two experiments were conducted to establish an ME content prediction model for normal corn for ducks based on the grain's chemical composition. In Experiment 1, observed linear relationships between the determined ME content of 30 corn calibration samples and proximate nutrients, acid detergent fiber (ADF), and neutral detergent fiber (NDF) were used to develop an ME prediction model. In Experiment 2, 6 samples of corn selected at random from the primary corn-growing regions of China were used for testing the accuracy of ME prediction models. The results indicated that the AME, AME(n), TME, and TME(n) were negatively correlated with crude fiber (r = -0.905), ADF (r = -0.915), and NDF (r = -0.95) contents, and moderately correlated with gross energy (GE; r = -0.55) content in corn calibration samples. In contrast, no significant correlations were found for CP, ether extract, and ash contents. According to the stepwise regression analysis, both NDF and GE were found to be useful for the ME prediction models. Because the maximum absolute difference between the in vivo ME determinations and the predicted ME values was 61 kcal/kg, it was concluded that, for White Pekin ducks, the latter could be used to predict the ME content of corn with acceptable accuracy.

Effect of dietary crude protein and energy on gosling growth performance and carcass trait

The study was undertaken to assess dietary CP and ME concentrations for optimum growth performance and carcass characteristics of goslings. In a 5 x 3 factorial arrangement, 360 one-day-old commercial generation Huoyan goslings were randomly assigned to experimental diets with 10.87, 11.37, 11.87, 12.37, and 12.87 MJ of ME/kg of diet; each contained 15.0, 17.5, and 20.0% CP, respectively, from 0 to 4 wk of age (WOA). Each dietary treatment was replicated 6 times. Body weight and feed consumption were measured, and carcass characteristics were evaluated at 4 WOA. The result showed that birds on a diet with 11.87, 12.37, and 12.87 MJ of ME/kg at 0 to 4 WOA exhibited greater BW gain than those on a diet with 10.87 and 11.37 MJ of ME/kg (P < 0.01), though BW gain was not different among 11.87, 12.37, and 12.87 MJ of ME/kg of diet. Mean BW gain of birds fed 17.5 and 20.0% CP diets was not different (P > 0.05), but they were higher than those on 15.0% dietary CP concentration (P < 0.001). Feed intake was not influenced by dietary ME levels (P > 0.05). Feed intake of birds fed 17.5 and 20.0% CP diets was higher than those of birds on 15.0% CP diets (P < 0.01). Feed conversion ratios of birds fed on 11.87, 12.37, and 12.87 MJ of ME/kg of diet were better than those fed on 10.87 and 11.37 MJ of ME/kg (P < 0.001). Feed conversion ratios of birds fed on 17.5 and 20.0% CP diets were better than those fed on 15.0% CP diets. Moreover, there were no significant interactions between CP and ME on growth performance. There was a direct relationship between dietary ME levels and eviscerated carcass percentage, abdominal fat percentage, and liver relative weight (P < 0.01). Breast and leg meat percentage were influenced by dietary CP concentrations significantly (P < 0.001). Thus, diets with 11.87 MJ of ME/kg and 17.5 to 20.0% CP were used more efficiently from 0 to 4 WOA by Huoyan goslings.

Effects of dietary metabolizable energy and crude protein content on the activities of digestive enzymes in jejunal fluid of Peking ducks

The response of digestive enzymes activities in the jejunal fluid of Peking ducks to dietary ME and CP content was investigated. In experiment 1, jejunal digesta from 24 cannulated male white Peking ducks of 18 wk of age were collected for 1 h out of every 4 h beginning at 0930 h on d 16, 18, and 20 of the experiment. The activities of amylase, trypsin, and chymotrypsin in jejunal fluid were determined. In experiment 2, 72 male cannulated ducks were randomly sorted into 4 groups. Four treatments consisted of combinations of 3,050 and 2,800 kcal/kg of ME, and 17.50 and 14.40% CP content were available ad libitum. Jejunal digesta samples were collected for 1 h every 4 h from 0930 to 1830 h on d 31, 33, and 35 of the experiment according to the results of experiment 1. The activities of amylase, trypsin, chymotrypsin, lipase, sucrase, and maltase in jejunal fluid were determined. In experiment 1, significant differences were found in the average activities of amylase and chymotrypsin among days. The collection time significantly affected the 3 enzyme activities, and average enzyme activities during the day were higher and more stable than during the night. In experiment 2, the effect of dietary ME content on the 6 digestive enzymes activities was not significant. But the dietary protein content significantly changed amylase, trypsin, and chymotrypsin activities.

Effect of Excess Methionine and Methionine Hydroxy Analogue on Growth Performance and Plasma Homocysteine of Growing Pekin Ducks

One experiment was conducted to study the effect of excess dl-methionine (DLM) and dl-2-hydroxy-4-methylthiobutanoic acid free acid (dl-HMB-FA) on duck growth. One-day-old male white Pekin ducklings were fed common starter diets from hatch to 21 d of age and then fed the experimental diets from 21 to 42 d of age. Three hundred twenty 21-d-old birds were allotted to 40 raised wire-floor pens with 8 birds per pen according to similar pen weight. There were 5 dietary treatments that included a methionine-adequate control diet and control diets supplemented with 2 levels of dry DLM (1 or 2%) or 2 equimolar levels of liquid dl-HMB-FA (1.13 or 2.26%). Each dietary treatment was replicated 8 times. At 42 d of age, weight gain, feed intake, and gain/feed were measured and plasma was collected to analyze homocysteine. Compared with ducks fed control diets, excess DLM or dl-HMB-FA supplementation reduced weight gain and feed intake of birds significantly. However, on the equimolar basis, at 1 or 2% supplemental methionine activity, dl-HMB-FA was less growth-depressing than DLM. According to the growth response to excess methionine, the tolerable upper limit of dietary methionine for growing ducks may be less than 1.38% when the methionine level of the control diet (0.38%) was considered. On the other hand, plasma homocysteine was elevated markedly when 2% DLM or 2.26% dl-HMB-FA was added to control diets, but plasma homocysteine of ducks fed 2.26% dl-HMB-FA supplemented diets was lower significantly than birds fed equimolar DLM-supplemented diets, which indicated the toxicity of excess methionine sources and less toxicity of dl-HMB-FA relative to DLM.

Methionine Requirements of Male White Peking Ducks from Twenty-One to Forty-Nine Days of Age

A dose-response experiment with 6 dietary methionine levels (0.20, 0.275, 0.35, 0.425, 0.50, and 0.575%) was conducted with male White Peking ducklings to estimate the methionine requirement of growing ducks from 21 to 49 d of age. One-day-old male White Peking ducklings were fed common starter diets from hatching to 21 d of age and then fed the experimental diets from 21 to 49 d of age. Three hundred thirty-six 21-d-old birds were allotted to 24 pens with 14 birds per pen according to similar pen weight. There were 6 dietary treatments, each containing 4 replicate pens. At 49 d of age, weight gain, feed intake, and feed/gain of ducks from each pen were measured, and 2 ducks selected randomly from each pen were slaughtered to evaluate the yields of abdominal fat, breast meat (including pectoralis major and pectoralis minor), and leg meat (including thigh and drum stick). Significant effects of dietary methionine on weight gain, breast meat, and abdominal fat were observed. Both weight gain and breast meat yield showed significant quadratic response to increasing dietary methionine, and abdominal fat decreased linearly (P < 0.05). According to the quadratic model, the optimal methionine requirement of male White Peking ducks from 21 to 49 d of age for maximum weight gain and breast meat yield were 0.377 and 0.379%, respectively.

Interrelationship Between Methionine and Cystine of Early Peking Ducklings

A 4 x 5 factorial experiment containing 4 cystine levels (0.325, 0.406, 0.487, or 0.568%) and 5 methionine levels (0.285, 0.385, 0.485, 0.585, or 0.685%) was conducted to evaluate the interrelationship between methionine and cystine in corn-peanut meal diet for Peking ducklings from hatch to 21 d of age. Eight hundred 1-d-old male white Peking ducklings were assigned to 20 experimental treatments. All treatments were replicated 4 times using 10 ducklings per pen. As dietary methionine level increased, weight gain and feed intake increased and then decreased; the quadratic response of weight gain was significant (P < 0.05). The methionine requirement for maximum efficiency of feed utilization (0.585%) was higher than for maximum weight gain (0.485%). According to the quadratic model, the optimal methionine requirement of Peking ducklings from hatch to 21 d of age was 0.481% (95% of the level at maximum response). The plasma uric acid concentration was very low (P < 0.05) when dietary methionine was 0.485%. When dietary methionine was excessive (0.685%), the plasma homocysteine concentration increased (P < 0.05). On the other hand, the cystine requirement of ducklings from hatch to 21 d of age was not more than 0.325%. A high level of cystine (0.568%) depressed weight gain and feed intake (P < 0.05), but cystine supplementation in the diets lowered the plasma homocysteine concentration (P < 0.05). There were no significant interactions between methionine and cystine on growth performance, plasma uric acid, and plasma homocysteine.

A simple scheme for probehead background suppression in one-pulse 1H NMR

A very simple method for reducing probehead background signal in one-pulse 1H nuclear magnetic resonance (NMR) spectra is presented. Two one-pulse spectra are recorded, the first with pulse length tp1, the second with an L-times longer pulse, e.g. with L = 2. The second spectrum scaled by 1/L is subtracted from the first. Since the weak pulses experienced by spins outside the coil are in the linear regime, the background from outside the coil is effectively subtracted out. The background suppression efficiency is approximately 1.5b2, where b is the ratio of the B1 field inside the coil relative to that outside the coil. Experimentally, background suppression by at least a factor of 10 was achieved. Examples of background suppression in 1H wideline as well as 1H fast magic-angle spinning (MAS) one-pulse spectra of clay and polymer samples are shown.

High-sensitivity multinuclear NMR spectroscopy of a smectite clay and of clay-intercalated polymer

The nuclear magnetic resonance (NMR) properties of a smectite clay low in paramagnetic ions, and NMR experiments to detect organic material near the silicate surfaces with high sensitivity, have been explored by 1H, 29Si, and 13C NMR. In oven-dried hectorite clay, 1H NMR reveals a sharp signal at 0.35 ppm that narrows significantly with spinning speed. It is assigned to the "inner" OH protons of the silicate layers. In fluorohectorite, where the OH groups are replaced by fluorines, no such 1H peak is observed. The assignment is further confirmed by the efficient cross-polarization observed in two-dimensional (2D) 1H-29Si HETCOR spectra, and by 29Si-detected REDOR experiments with 1H-dephasing in the 29Si dipolar field, which yield a 1H-29Si distance of 2.9 + 0.4 A. In these 1H-29Si experiments, the sensitivity of the 29Si signal is enhanced at least fivefold by refocusing the decay resulting from the inhomogeneous broadening of the single 29Si peak, stretching the 29Si signal out over 80 ms. The small 1H linewidth of this signal at spinning frequencies exceeding 4 kHz is attributed to the large proton-proton distances in the clay. The upfield isotropic chemical shift of the OH groups is explained by their inaccessibility to hydrogen-bonding partners, as a result of their location in hexagonal "cavities" of the clay structure. The well-resolved, easily selectable OH-proton signal and the high-sensitivity 29Si detection open excellent perspectives for NMR studies of composites of clays with organic molecules. Two-dimensional 1H-29Si and 1H-1H chemical-shift correlation experiments enable efficient detection of the 1H spectrum of organic segments near the clay surface. Combined with 1H spin diffusion, the organic segments at up to several nanometers from the clay surfaces can be probed. A 2D 1H-13C correlation experiment yields the 13C spectrum of the organic species near the clay surfaces. A mobility gradient of intercalated poly(ethylene oxide), PEO, segments is proven in 1H-3Si WISE experiments with spin diffusion.

Retroperitoneoscopic nephrectomy (RN): using the gravity technique to facilitate specimen entrapment

BACKGROUND

Kidney entrapment is generally considered to be a difficult step in retroperitoneoscopic nephrectomy (RN). Normally, a large device is needed to accommodate the specimen, which may measure </=14 x 10 cm. There is just too little space to maneuver either the entrapment device or the specimen. Herein we describe a technique that can overcome this difficulty and even turn the space limitation to advantage.

METHODS

After the nephrectomy, the specimen is pushed caudally. A 15-mm Endocatch is inserted via the posterior cranial port. It is positioned strategically underneath the specimen so that when the entrapment bag is released, the specimen will have no room to move (because of the limited space) and will simply fall into the bag (because of gravity).

RESULTS

We have used this technique for our last four cases of retroperitoneoscopic nephrectomy and found that it remarkably shortened the operative time for this step.

CONCLUSION

One of the criticisms leveled against retroperitoneoscopic surgery concerns the problems posed by the space limitation. This technique turns the space limitation into an advantage and guarantees successful specimen entrapment.

[Regulation of fungal elicitors on the cell growth and biosynthesis of saponin of Panax ginseng cell suspension culture]

Adding fungal elicitors to the Panax ginseng cell suspension cultures, the biosynthesis of saponin was obviously induced, the total productivity of saponin in cultures could increase more than 30% of the control. During elicitation, the accumulation patterns of saponin in suspension cultured cells were changed, the culture time for maximum biosynthesis of saponin was shortened 2-4 days comparing with that of the control, and about 80% of biosynthetic saponin in elicited cells was secreted into medium, meanwhile the uptake for sucrose in medium of cells was enhanced, and the disturbing of pH in medium was observed, which predicated that an ion exchange occurred between elicited cells and medium.

Identification of two novel cis-elements in the promoter of the prostate-specific antigen gene that are required to enhance androgen receptor-mediated transactivation

A monomeric androgen responsive element (ARE) is not sufficient to mediate significant androgen induction of the prostate-specific antigen (PSA) gene. Co-transfection experiments using a series of 5'deletion fragments of the proximal promoter region of the PSA gene linked to bacterial chloramphenicol acetyltransferase (CAT) as a reporter have identified two motif sequences which are indispensable for androgen receptor (AR)-mediated transactivation of the PSA promoter and have been designated as motifs A and B respectively. Of note, motif B alone has very little independent enhancer activity regardless of the presence or absence of androgen, whereas multi-copies of motif A exert androgenic inducibility for a heterologous promoter independent of the presence of ARE. Nucleotide substitutions in either motif significantly decrease the androgen inducibility and the nuclear protein binding ability. Furthermore, gel band shift experiments consistently demonstrate that nuclear proteins can bind these motifs, and they are non-receptor factors. Our data indicate that these two DNA motifs are novel cis -regulatory elements and exhibit different mechanisms in cooperation with ARE for AR-mediated transactivation.