[Application of bridging study design in preventive vaccine clinical trials].

Bridging study in vaccine clinical trials means a series of small-scale additional tests on the basis that the original safety and effectiveness of a vaccine have been confirmed in clinical trials, to prove that the characteristics of safety, immunogenicity and effectiveness of a vaccine are similar or consistent after component, population and immunization procedure change to other types which can extrapolate data from existing clinical trials. Compared with traditional vaccine clinical trials, bridging trials can promote the approval of vaccines to the market, accelerate the expansion of vaccine application, and promote the use of vaccines across regions and populations. In recent years, the application of bridge study design in vaccine clinical research has become more and more common. In order to better guide and promote the application of bridging trial design in the field of vaccine clinical research, we reviewed the design characteristics and application examples of bridging study design in vaccine clinical trials, and systematically elaborated the design ideas, key points and statistical evaluation methods of bridging study.

[Analytical value of histological research and application of RNAscope technology in liver diseases].

RNAscope is a new generation of in situ hybridization technology and with the advantage of new probe design, it is now being gradually applied to a wide range of research fields, and its research scope is constantly expanding. Our country has large number of liver disease patients, so there is a great demand for histological testing and research evaluation based upon biological information. This technology has unique specificity and sensitivity in situ level, which makes up for the technical defects of immunohistochemistry and traditional in situ hybridization. Realizing the multiplicity and monomolecular level detection, the qualitative and quantitative analysis of nucleic acid level can be carried out in many aspects of the field of liver disease, and the visual evaluation can be achieved by combining it with tissue in situ to highlight the value of "gold standard". This article summarizes the recent year's application of RNAscope technology carried out in liver histology field.

Effects of fermented cottonseed meal inclusions on growth performance, serum biochemical parameters and hepatic lipid metabolism of geese during 28-70 d of age.

The aim of this study was to investigate the effects of solid-state fermented cottonseed meal (FCSM) inclusion levels on the growth performance, serum biochemical parameters and hepatic lipid metabolism in geese from 28 to 70 d of age. A total of 288 twenty-eight-d-old male geese were randomly divided into 4 treatments with FCSM levels of 0, 5, 15 and 25% including 0, 22.74, 67.33, 111.27 mg FG/kg diet, respectively. Each treatment contained 6 replicates and 12 birds per replicate. Treatments of FCSM inclusions from 0 to 25% had no effect on growth rate and feed intake in geese during d 28 to 70. The F/G ratio was increased (P < 0.05) in geese fed the diet with 25% FCSM compared with birds fed the diet with 0% FCSM. Treatment with 25% FCSM levels had no effect on the contents of TC, TG, HDL-C, LDL-C, but increased (P < 0.05) AST and ALT activities in serum of geese at d 70. Treatment with 25% FCSM increased the contents of FG, HDL-C, TC, C18:2n6, C20:4n6 and PUFA and decreased (P < 0.05) the contents of NEFA, SFA, MUFA in liver compared with treatment of 0% FCSM inclusion. Additionally, treatment with 25% FCSM decreased (P < 0.05) the PPARα, AMPK, and LXR mRNA expression related to lipid deposition, and increased (P < 0.05) PPARγ and ACC mRNA expression related to lipolysis in liver compared with birds fed the diet with 0% FCSM. Overall, treatment with 0 to 15% FCSM (<=67.33 mg FG/kg diet) had no adverse effects on the growth performance and lipid metabolism of geese. However, treatment fed 25% FCSM (111.27 mg FG/kg diet) decreased feed efficiency and promoted hepatic lipid deposition associated with the alteration of related gene expression in geese at 28 to 70 d of age.

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.

Research Note: Developmental changes of glucose metabolism are associated with insulin signaling in goose embryo.

This study aimed to investigate whether the developmental changes in glucose metabolism were associated with insulin signaling in the middle and later stages of goose embryos. Serum and liver were sampled on embryonic day 19, 22, 25, 28, and day of hatchment, with 30 eggs at each sampling time point, and 6 replicates of 5 embryos. The embryonic growth traits, serum glucose, hormone levels, and the hepatic mRNA expressions of target genes related to glucose metabolism and insulin signaling were measured at each time point. Relative body weight, relative liver weight, and relative body length decreased linearly and quadratically from embryonic day 19 to day of hatchment, while relative yolk weight decreased linearly from embryonic day 19 to day of hatchment. Serum glucose, insulin, and free triiodothyronine levels increased linearly with increasing incubation time, while no differences were observed in serum glucagon and free thyroxine levels. The hepatic mRNA expression related to glucose catabolism (hexokinase, phosphofructokinase, and pyruvate kinase) and insulin signaling (insulin receptor, insulin receptor substrate protein, Src homology collagen protein, extracellular signal-regulated kinase, and ribosomal protein S6 kinase, 70 ku) increased quadratically from embryonic day 19 to day of hatchment. The expression of citrate synthase and isocitrate dehydrogenase mRNA decreased linearly and quadratically respectively from embryonic day 19 to day of hatchment. Serum glucose levels were positively related to serum insulin (r = 1.00) and free triiodothyronine (r = 0.90) levels, as well as the hepatic mRNA expression of insulin receptor (r = 1.00), insulin receptor substrate protein (r = 0.64), extracellular signal-regulated kinase (r = 0.81), and ribosomal protein S6 kinase, 70 ku (r = 0.81) related to insulin signaling. In conclusion, glucose catabolism was enhanced and had positive correlations with the insulin signaling in the middle and later stages of geese embryogenesis.

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.

Change of zinc mobilization and gene expression of key zinc transport proteins between the yolk sac membrane and liver of duck embryonic developing.

Zinc (Zn) deposition in egg yolk is essential for the rapid growth and complete development of the avian embryo. Thus, it is crucial to obtain maximal Zn mobilization at an appropriate time during development in favor of the survival of avian embryos. The aim of this study was to study the developmental change of Zn mobilization and gene expression related to key Zn transport proteins between the yolk sac membrane and embryonic liver from the incubation d 17 (E17) to d 32 (E32) during duck embryonic developing. The weights of duck embryo, embryo without yolk sac, and embryonic liver increased as well as the yolk sac weight decreased linearly (P < 0.0001) when incubation day increased. The Zn concentration in the yolk sac did not change from E17 to E29 and only declined significantly from E29 to E32 of duck embryos, while hepatic Zn level decreased linearly as with the increased incubation time (P < 0.01). When the incubation day increased, the decreased Zn amount in the yolk sac and the increased Zn amount in the embryonic liver were observed (P < 0.0001). The calculated transfer-out rate of Zn in the yolk sac and transfer-in rate of Zn in livers were both increased from E23-26 to E29-32 (P < 0.01). Among E17, E23 and E29, the solute carrier family 39 member (ZIP) of ZIP10, ZIP13, and ZIP14 genes mRNA expressions were increased in yolk sac membrane but were decreased in the embryonic liver, while metallothionein 1 mRNA expression was increased both in the yolk sac membrane and liver (P < 0.05). In conclusion, yolk sac membrane and embryonic liver tissues displayed the similar developmental patterns of Zn mobilization and metallothionein 1 mRNA expression from E17 to E32 during duck embryonic developing. The appropriate time of the maximal rate of Zn mobilization were observed between E29 and E32 of duck embryo, associated with the significant changes of gene expression related to some key Zn transport proteins on E29 in yolk sac membrane and liver tissues.

Research Note: The comparative study of energy utilization in feedstuffs for Muscovy ducks between in vivo and in vitro.

Our study was aimed to investigate the effects of dietary metabolizable energy (ME) and crude protein (CP) levels on the digestive physiology in the jejunal fluid of Muscovy ducks to provide digestive parameters for in vitro digestion. There were 6 ME levels (11.0, 11.5, 12.0, 12.5, 13.0, and 13.5 MJ/kg; Exp. 1) and six CP levels (140, 155, 170, 185, 200, and 215 g/kg; Exp. 2) and each treatment included 6 replicates with 3 ducks each replicate. In Exp. 3, the comparison of energy utilization was investigated between in vivo and in vitro using the digestion parameters obtained from Exp. 1 and 2. As dietary ME was increased, the chymotrypsin activity was increased linearly (P < 0.05), and the concentrations of Ca2+, K+, and Mg2+ were increased quadratically (P < 0.05) in the jejunal fluid. As dietary CP was increased, amylase activity was increased linearly (P < 0.05), whereas trypsin and chymotrypsin activities and Ca2+ concentration were increased quadratically (P < 0.05). The pH values were decreased quadratically with the increased dietary ME or CP levels (P < 0.05). The optimal digestion parameters for energy feedstuffs with 307.26 U/mL amylase, 54.68 U/mL trypsin, 24.90 U/mL chymotrypsin, 104.39 mmol/L Na+, 51.25 mmol/L Cl-, and pH 7.79; for protein feedstuffs with 381.88 U/mL amylase, 72.84 U/mL trypsin, 11.98 U/mL chymotrypsin, 93.53 mmol/L Na+, 46.25 mmol/L Cl-, and pH 7.80, respectively. Using the optimal digestion parameters for in vitro digestion, energy utilization in vitro reflected the degree of the apparent energy utilization of corn, sorghum, and barley as well as true energy utilization of soybean meal, rapeseed meal, and cottonseed meal in vivo and the variation of digestion was lower in vitro than in vivo.

Population pharmacokinetics of ustekinumab in patients with active psoriatic arthritis.

PURPOSE: To characterize the population pharmacokinetics of subcutaneous ustekinumab, a human IgG1Kappa; monoclonal antibody against interleukin-12/23p40, using data from a randomized, double-blind, placebo-controlled Phase II study in patients with active psoriatic arthritis (PsA). METHODS: A total of 786 quantifiable serum ustekinumab concentrations from 130 patients were analyzed using a nonlinear mixed-effects modeling approach. A 1-compartment model with first-order absorption and elimination was selected as the structural model. RESULTS: The population typical mean (percent relative standard error (%RSE)) values for apparent clearance (CL/F), apparent volume of distribution (V/F), and absorption rate constant (ka) obtained from the final covariate model were 0.465 l × day-1 (5.1%), 14.3 l (4.4%), and 0.427 day-1 (3.9%), respectively. The between-subject variability in CL/F, V/F, and ka were 53.9%, 42.3%, and 82.4%, respectively. Patient body weight and antibody-to-ustekinumab status were significant covariates affecting the CL/F and/or V/F of ustekinumab. None of the other factors evaluated, such as age, sex, race, baseline disease characteristics, concomitant methotrexate or nonsteroidal anti-inflammatory drugs, and past use of immunosuppressives, biologics, systemic corticosteroids, or disease-modifying antirheumatic drugs, were found to have significant effects on the pharmacokinetics of ustekinumab. CONCLUSION: The pharmacokinetics of ustekinumab in patients with PsA are comparable to those in patients with moderate-to-severe plaque psoriasis which was previously investigated.

Mineral requirements in ducks: an update.

Mineral nutrition plays a critical role in growth and bone mineralization in meat ducks as well as reproductive performance in duck layers and duck breeders. In addition to improving production performance parameters, minerals are also essential to support several enzymatic systems to enhancing antioxidant ability and immune function. This review explores the biological function and metabolism of minerals in the body, as well as mineral feeding strategy of various species of ducks. Topics range from mineral requirement to the physiological role of macroelements such as calcium and phosphorus and microelements such as zinc and selenium, etc. As with the improvement of genetic evolution and upgrade of rearing system in duck production, mineral requirements and electrolyte balance are urgent to be re-evaluated using sensitive biomarkers for the modern duck breed characterized by the rapid growth rate and inadequate bone development and mineralization. For duck breeders, mineral nutrition is not only required for maximal egg production performance but also for maintaining normal embryonic development and offspring's performance. Therefore, the proper amounts of bioavailable minerals need to be supplemented to maintain the mineral nutritional state of duck species during all phases of life. In addition, more positive effects of high doses microelements supplementations have been revealed for modern meat ducks subjected to various stresses in commercial production. The nutritional factors of mineral sources, supplemental enzymes, and antinutritional factors from unconventional ingredients should be emphasized to improve the effectiveness of mineral nutrition in duck feed formulation. Organic mineral sources and phytase enzymes have been adopted to reduce the antagonistic action between mineral and antinutritional factors. Therefore, special and accurate database of mineral requirements should be established for special genotypes of ducks under different rearing conditions, including rearing factors, environmental stresses and diets supplemented with organic sources, phytase and VD3.

Protective effect of curcumin on ochratoxin A-induced liver oxidative injury in duck is mediated by modulating lipid metabolism and the intestinal microbiota.

Curcumin has antioxidant functions, regulates the intestinal microbial composition, and alleviates mycotoxin toxicity. The present study aimed to explore whether curcumin could alleviate ochratoxin A (OTA)-induced liver injury via the intestinal microbiota. A total of 720 mixed-sex 1-day-old White Pekin ducklings were randomly assigned into 4 groups: CON (control group, without OTA), OTA (fed a diet with 2 mg/kg OTA), CUR (ducks fed a diet with 400 mg/kg curcumin), and OTA + CUR (2 mg/kg OTA plus 400 mg/kg curcumin). Each treatment consisted of 6 replicates and 30 ducklings per replicate. Treatment lasted for 21 D. Results were analyzed by a two-tailed Student t test between 2 groups. Our results demonstrated that OTA treatment had the highest serum low-density lipoprotein (LDL) level among 4 groups. Compared with OTA group, OTA + CUR decreased serum LDL level (P < 0.05). OTA decreased liver catalase (CAT) activity in ducks (P < 0.05), while addition of curcumin in OTA group increased liver CAT activity (P < 0.05). 16S ribosomal RNA sequencing suggested that curcumin increased the richness indices (ACE index) and diversity indices (Simpson index) compared with OTA group (P < 0.05) and recovered the OTA-induced alterations in composition of the intestinal microbiota. Curcumin supplementation relieved the decreased abundance of butyric acid producing bacteria, including blautia, butyricicoccus, and butyricimonas, induced by OTA (P < 0.05). OTA also significantly influenced the metabolism of the intestinal microbiota, such as tryptophan metabolism and glyceropholipid metabolism. Curcumin could alleviate the upregulation of oxidative stress pathways induced by OTA. OTA treatment also increased SREBP-1c expression (P < 0.05). The curcumin group had the lowest expression of FAS and PPARG mRNA (P < 0.05) and the highest expression of NRF2 and HMOX1 mRNA. These results indicated that curcumin could alleviate OTA-induced oxidative injury and lipid metabolism disruption by modulating the cecum microbiota.

Effects of sources and levels of liquor distiller's grains with solubles on the growth performance, carcass characteristics, and serum parameters of Cherry Valley ducks.

Liquor distiller's grains with solubles (LDGS) is high in yield and rich in crude fiber and crude protein, which suggests that LDGS might be developed and used as unconventional feedstuff for ducks. The aim of this study was to investigate the effects of sources and levels of LDGS on growth performance, carcass characteristics, serum parameters, and intestinal morphology of Cherry Valley ducks from 15 to 42 D of age. A total of 3,300 15-day-old male ducks were randomly assigned into a 1 plus 2 × 5 factorial design including 2 different sources of LDGS (unfermented LDGS [ULDGS] and fermented LDGS [FLDGS]) at 5 levels (4, 8, 12, 16, and 20%) for 4 wk. Each treatment group included 6 pens with 50 ducks per pen. Levels of dietary LDGS and the interaction between sources and levels of LDGS had no effect on final body weight, average daily feed intake (ADFI), average daily gain, or feed-to-gain ratio (F:G) of ducks from day 15 to 42 (P > 0.05). Compared with dietary ULDGS, dietary FLDGS increased final body weight (P < 0.05) and ADFI (P < 0.05) and decreased the F:G (P = 0.03). The levels of LDGS and interaction effect between levels and sources of LDGS had no effect on carcass characteristics (P > 0.05). Regardless of the inclusion level, ducks fed with diets containing FLDGS had a higher percentage of thigh muscle (P < 0.01) than birds fed with diets containing ULDGS. Sources of dietary LDGS, levels of dietary LDGS, and their interaction had no effect on serum biochemistry parameters (P > 0.05) and intestinal morphology, including villus height, crypt depth, and villus height-to-crypt depth ratio (P > 0.05). In conclusion, the inclusion of LDGS in the diet at levels up to 20% had no negative effect on the growth performance, carcass characteristics, serum parameters, and intestinal morphology of ducks. Compared with ULDGS, FLDGS increased final body weight, ADFI, and thigh muscle yield and decreased the F:G of ducks. Therefore, LDGS, especially with fermentation, could be developed as an unconventional feedstuff resource for ducks from 15 to 42 D of age.

Dietary curcumin enhances intestinal antioxidant capacity in ducklings via altering gene expression of antioxidant and key detoxification enzymes.

The study investigated the effects of dietary curcumin supplementation on tissue distribution of curcumin and its metabolites, intestinal antioxidant capacity, and expression of detoxification-related genes in ducks. A total of 720 one-day-old male Cherry Valley Pekin ducklings (initial BW 58.6 ± 0.1 g) were randomly assigned to 4 dietary groups each with 6 replicates of 30 ducks using a single factorial arrangement design. Ducks in the control group were fed a basal diet and the remainder were fed the basal diet supplemented with 200, 400, or 800 mg/kg curcumin. The experiment lasted for 21 D. Curcumin was present at 13.12 to 16.18 mg/g in the cecal digesta, 75.50 to 575.40 µg/g in jejunal mucosa, 35.10 to 73.65 µg/g in liver, and 7.02 to 7.88 µg/mL in plasma. The jejunal and hepatic contents of curcumin increased significantly (P < 0.05) in response to supplementation with 400 and 800 mg/kg of curcumin respectively, compared with 200 mg curcumin/kg group. There was a linear (P < 0.001) effect of dietary curcumin on relative abundance of SOD1, GPX1, CAT, HO-1, and Nrf2 transcripts, and a quadratic (P < 0.001) increase in the activities of GSH-Px and T-AOC in jejunal mucosa. The expression of CYP1A4, CYP2D17 increased and CYP1B1, CYP2A6 decreased linearly (P < 0.001) with dietary curcumin concentrations. In addition, dietary curcumin increased gene expression of GST, MRP6, and ABCB1 in jejunal mucosa. In conclusion, dietary supplementation with 200 to 800 mg/kg curcumin enhanced the accumulation of curcumin and its metabolites in jejunum as well as increasing the antioxidant capacity and detoxification potential, which play major roles in the protection of duck intestines against damage.

Effects of dietary rapeseed meal inclusion levels on growth performance, organ weight, and serum biochemical parameters in Cherry Valley ducks.

The aim of this study was to investigate the effects of the inclusion levels of different types of rapeseed meal (RSM) on performance, organ weight, and serum biochemical parameters in Cherry Valley ducks in the starter period and grower-finisher period. In Exp. 1, a total of 750 seven-day-old male ducklings were divided into 5 dietary treatments with 6 replicate pens of 25 birds per pen. The starter diets with the inclusion of 0, 5, 10, 15, or 20% of double-low RSM contained 0, 1.37, 2.15, 3.46, or 5.31 µmol glucosinolates (GLS)/g in the finished feed (from day 7 to 21). In Exp. 2, a total of 900 fifteen-day-old male ducklings were divided into 6 dietary treatments with 6 replicate pens of 25 birds per pen. The grower-finisher diets with the inclusion of 0, 5, 10, 15, 20, or 25% of Indian RSM contained 0, 7.67, 15.34, 24.66, 31.21, or 38.44 µmol GLS/g in the finished feed (from day 15 to 42). For ducklings in the starter period (Exp. 1), body weight gain and feed intake decreased linearly as the dietary double-low RSM inclusion level increased at day 7 to 14, while growth rate was not influenced by dietary double-low RSM inclusion levels at day 15 to 21 and day 7 to 21. For ducks in the grower-finisher period (Exp. 2), growth performance decreased linearly as the dietary RSM inclusion level increased from 5 to 20%. In addition, dietary RSM inclusion levels induced liver enlargement in ducklings at day 21 (5 to 20% double-low RSM with 1.37 to 5.31 µmol/g GLS) and thyroid enlargement accompanied by increased serum AST and ALP activities in ducks at day 42 (5 to 15% Indian RSM with 7.67 to 23.66 µmol/g GLS). Therefore, our results indicated that the upper limit of using RSM sources in feed formulation should consider the anti-nutritional factor of GLS content at different stages of duck growth.

Fermentation of flaxseed cake increases its nutritional value and utilization in ducklings.

Flaxseed cake (FSC) is a potential alternative feed source in poultry. However, cyanogenetic glycosides limit its widespread use in feed. In this study, we optimized the parameters of fermentation by Aspergillus niger and Candida utilis and compared the growth performance, serum lipid parameters, and organ indexes of Cherry Valley duckling feed with unfermented FSC (UFSC) or fermented FSC (FFSC). A total of 420 one-day-old male Cherry Valley ducklings were randomly assigned into a 1 plus 2 × 3 factorial design including 2 different FSC resources (UFSC and FFSC) at 3 levels (50, 100, or 150 g/kg) for 3 wk. Each treatment group included 6 pens with 10 ducklings per pen. The hydrocyanic acid (HCN) level was reduced under the following conditions: 1:0.8 FSC:water (w:v), inoculum ratio of 1 mL:1 mL, 30°C, and 60 h. FFSC had higher crude protein (CP) and calcium (Ca) levels and lower HCN levels compared with UFSC (P < 0.05). There was no interactive effect between FSC sources and levels on growth performance. Final body weight (FBW), average daily feed intake (ADFI), and average daily gain (ADG) in UFSC groups and ADFI in FFSC groups decreased linearly with increasing FSC levels (P < 0.01). There were no differences in FBW, ADG, or feed:gain ratio (F/G) among FFSC groups, and all 7 FSC groups had no differences in the F/G ratio (P > 0.05). Dietary FSC supplementation decreased triglyceride (TG) (P < 0.01), total cholesterol (TC) (P < 0.01), high-density lipoprotein (HDL) (P = 0.01), and low-density lipoprotein (LDL) (P < 0.01). No interactive effect between FSC levels and sources was observed for serum TG, TC, HDL, or LDL. Ducklings fed FFSC had lower TG (P < 0.01), TC (P = 0.05), and LDL (P < 0.01) levels compared with ducklings fed UFSC. The 150 g/kg FFSC group had the lowest TG, TC, HDL, and LDL levels among all 7 groups. Flaxseed cake supplementation decreased the relative weight of the left breast, but FFSC increased the relative weight of the gizzard compared with UFSC. In conclusion, fermentation could increase the nutritional value and usage of FSC in ducklings.

High calcium to phosphorus ratio impairs growth and bone mineralization in Pekin ducklings.

Two experiments were conducted to investigate the effect of high dietary calcium (Ca) level on growth performance, Ca and phosphorus (P) metabolism, and nutrient utilization in ducklings subjected to normal and low P levels in diets. A completely randomized design was used with a factorial arrangement of 2 total dietary P levels [normal-P (0.60%) and low-P (0.45%) groups] × 4 dietary Ca levels [low-Ca (0.55%), normal-Ca (0.75%), medium-Ca (0.95%) and high-Ca (1.15%) groups)]. Compared to normal-P group, low-P group had lower (P < 0.05) final body weight (BW), average daily gain (ADG), and average daily feed intake (ADFI) and reduced (P < 0.05) serum Ca and P levels, bone Ca, P, and ash content, and bone mineral density in ducklings during the starter period. Under the low-P group, birds from high-Ca group had lower (P < 0.05) final BW, ADG, ADFI, bone ash content, bone mineral density, and the utilization of energy, Ca, and P than those from low-Ca, normal-Ca, and medium-Ca groups. Our results indicate that high-Ca diet induced greater growth suppression and bone mineralization loss in ducklings fed a low-P diet. The aggravated negative effect of high dietary Ca level with a low P level might be related to the elevated serum alkaline phosphatase activity and the reduced utilization of energy, Ca, and P.

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.

Impact of maternal heat stress in conjunction with dietary zinc supplementation on hatchability, embryonic development, and growth performance in offspring broilers.

The aim of this study was to investigate whether maternal dietary supplementations with different zinc (Zn) sources could reduce the deleterious effect of maternal heat stress on hatchability performance and progeny growth performance. A completely randomized design (n = 6) with 2 maternal environmental temperatures [normal 21 ± 1°C (NT) vs. high 32 ± 1°C (HT)] × 3 maternal dietary supplemental Zn levels [Zn-unsupplemented control diet (CON), the control diet + 110 mg of Zn/kg of diet as either inorganic ZnSO4 (iZn) or organic Zn with a moderate chelation strength (oZn)] was used. HT decreased (P < 0.05) fertility, hatchability, chick hatch weight, and embryonic survival. HT also decreased (P ≤ 0.05) progeny BW, ADG, and ADFI at one to 21, 22 to 28, and 29 to 42 d of age as well as breast muscle ratio and plasma aspartate aminotransferase and creatine kinase activities at 42 d of age. Maternal dietary Zn supplementation with either iZn or oZn increased (P < 0.004) Zn contents in yolk and liver, non-weak chick ratio, as well as progeny BW, ADFI, and survivability at one to 21 d of age. Notably, the addition of oZn increased (P < 0.05) hatchability and progeny thigh meat quality by reducing b* value. The progeny ADG at one to 21 d and 22 to 28 d of age and BW at 28 d of age from maternal NT were not affected (P > 0.46) by maternal dietary Zn supplementation, but the above 3 indices from HT-iZn (P < 0.05) and HT-oZn (P < 0.003) were higher than those from HT-CON. Our results indicate that maternal heat stress impairs hatching performance, embryonic development, and progeny growth performance, inducing metabolic changes, while supplementation of Zn in maternal diets regardless of Zn sources improved hatch chick quality and survivability of offspring and alleviated the negative effect of maternal heat stress on growth performance of offspring during the starter period. In addition, maternal dietary supplementation with the organic Zn improved hatchability and progeny meat quality.

Synthesis of "cactus" top-decorated aligned carbon nanotubes and their third-order nonlinear optical properties.

We report a new morphology of "cactus" top-decorated aligned carbon nanotubes grown by the PECVD method using pure C2H2 gas. Unlike most previous reports, no additional carrier gas is used for pretreatment. Carbon nanotubes can still grow and maintain the tubular structure underneath the "cactus" tops. It is proposed that the H atoms produced by the dissociation of C2H2 activate the catalyst nanoparticles. Scanning electron microscopy (SEM) shows that the top "cactus" morphology is composed of a large quantity of small nanosheets. Transmission electron microscopy (TEM) reveals the amorphous carbon nature of these "cactus" structures. The formation of these "cactus" structures is possibly due to covalent absorption and reconstruction of carbon atoms on the broken graphite layers of nanotubes produced by the strong ion bombardment under plasma. The third-order optical nonlinearities and nonlinear dynamics are also investigated. The third-order nonlinear susceptibility magnitude /chi(3)/ is found to be 2.2 x 10(-11) esu, and the relaxation process takes place in about 1.8 ps.