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There is an increased interest among poultry nutritionists to increase the linoleic acid (LA) content of the egg, which possesses many benefits for human health. This fatty acid must be provided by the diet as the bird’s body cannot synthesise it. The present study evaluated the influence of different levels of dietary LA on the productive performance, egg quality and yolk lipid profile of Longyan laying ducks. In total, 900 Longyan female laying ducks aged 24 weeks were assigned to six dietary treatments, each containing 6 replicates of 25 ducks. The six dietary treatments contained six incremental levels of LA (analysed content: 0.36, 0.66, 0.80, 1.07, 1.28, and 1.45%) and the experimental diets were offered for the following 20 weeks. The results showed that different supplemental levels of dietary LA had no effects on egg production traits, concentrations of plasma cholesterol and triglycerides, or low or high-density lipoprotein cholesterol (p > .05). There was a linear increase in yolk colour (p

This study evaluated the effects of barley inclusion and glucanase supplementation on the productive performance and digestive function in laying ducks. The experiment used a randomized design with a 5 × 2 factorial arrangement of 5 graded levels of barley (0%, 15%, 30%, 45% and 60%) with or without 1.5 g/kg β-1,3-1,4-glucanase (15,000 U/kg). During the experimental period of 120 d, the weight and total number of eggs within each pen were recorded daily, and egg quality was determined every 4 wk. At the end of the experiment, 3 randomly selected ducks within each replicate were sacrificed, then duodenal digesta and jejunal mucosa was collected. Dietary inclusion of barley had no effects on egg production, daily egg mass or FCR, but supplementation with glucanase improved egg production and FCR (P

The increased consumption of protein derived from poultry demands greater poultry production, but increased poultry production (meat and eggs) is dependent on the fertility of the parent flocks. Clearly, the fertility of poultry flocks is associated with the fertility of both males and females, but the low numbers of males used for natural or artificial insemination mean that their role is more important. Thus, enhancing the semen volume, sperm concentration, viability, forward motility, and polyunsaturated fatty acids in sperm, as well as protecting against oxidative damage, could help to optimize the sperm membrane functionality, mitochondrial activity, and sperm-egg penetration, and thus fertility. Therefore, this review summarizes the nutritional factors that could improve the fertility of poultry males as well as their associated mechanisms to allow poultry producers to overcome low-fertility problems, especially in aging poultry males, thereby obtaining beneficial impacts on the poultry production industry.

The objective of this study was to investigate the effects of dietary iron (Fe) on reproductive performance of Chinese Yellow broiler breeder hens during the egg-laying period. A total of 480, 55-wk-old hens were balanced for laying rate and then randomly allotted into 5 groups, each with 6 replicates (8 cages for each replicate with 2 birds per cage). The trial was for 10 wk. Birds were fed diet with 44, 58, 72, 86, or 100 mg/kg Fe contained feed. Laying performance, biochemical indices and reproductive hormones in plasma, egg quality, ovarian and oviductal variables, tibial breaking strength, and hatching performance were determined. The key performance variables hematocrit, hatchability of live embryos, and tibial breaking strength were selected for analysis by quadratic polynomial (QP) and broken-line (BL) regressions to better determine optimal dietary Fe level. Qualified egg (excluding those with double-yolk, soft-shell, cracked, very small malformed, etc.) rate tended to decrease with the lowest and highest dietary Fe levels. Hematocrit was affected (P = 0.003) by dietary Fe, along with linear (P = 0.017) and quadratic (P = 0.002) effect. There was a significant effect (P = 0.034) of dietary Fe level on tibial breaking strength of breeder hens with a quadratic (P = 0.044) effect. Breeder hens fed inadequate (44 mg/kg diet) or excess (100 mg/kg) Fe both had lower (P < 0.05) tibial breaking strength compared to that of hens fed 86 mg/kg Fe. Hatchability of live embryos was affected (P = 0.004) by diet; with both linear (P = 0.014) and quadratic (P = 0.001) effects. Maximal hatching of live embryos occurred with diets of breeder hens containing 72 mg/kg Fe. From the QP and BL models fitted to hematocrit, tibial breaking strength, and hatchability variables, the optimal dietary Fe level for Chinese Yellow broiler breeder hens in the laying period was 70–90 mg/kg. The daily Fe fed (allowance) was about 8–11 mg.

This study evaluated the changes in eggshell mechanical properties, ultrastructure, calcium metabolism-related serum indices, and gene expression in eggshell gland during eggshell formation between laying ducks in the peak (young duck) and late phase (aged duck) of production. A total of 84 healthy young (31 wk of age) and 84 healthy aged (65 wk of age) Longyan laying ducks were each divided into 6 replicates of 14 birds, and caged individually. All the ducks were fed in one house with the same corn-soybean meal-based diet for 5 wk. The eggshell mechanical properties (shell proportion, thickness, breaking strength, and fracture toughness) and chemical components (matrix proteins, calcium, phosphorus, and magnesium) decreased in aged laying ducks (P < 0.05). Shell structural indices: total thickness, effective thickness and its proportion decreased, whereas mammillary knob width and its proportion increased (P < 0.05). The regulation values of early fusion, cuffing, caps, and total score of mammillary knobs were higher in aged laying ducks relative to the young ducks (P < 0.05). During the initial, growth and terminal stages of eggshell formation, shell thickness and breaking strength (terminal), shell weight, and its proportion (terminal) decreased in aged laying ducks (P < 0.05). Ultrastructural changes during shell formation indicated that the mammillary-knob density and effective thickness decreased (P < 0.05). Decreases occurred in serum content of phosphorus (growth), and estradiol and calcium contents (terminal) (P < 0.05). Relative expression of Ca2+ transporter and HCO3− exchanger, and matrix proteins genes decreased in aged laying ducks (P < 0.05) at all stages of eggshell formation. Collectively, the decreased incidence of early fusion and caps, increased thickness and width of mammillary knobs, and decreased effective thickness are the crucial differences leading to the compromised mechanical properties of eggshell in the late laying period. A disturbed regulation of calcium metabolism and uterine expression of ion transporters, especially for HCO3− exchange of aged laying ducks likely contribute to age-induced ultrastructural deterioration of the eggshell.

This study evaluated dietary Zn supplementation on productive performance, eggshell quality and ultrastructure, and calcium metabolism during eggshell formation in laying ducks. A total of 360 Longyan laying ducks (45-wk) were randomly divided into 5 treatment groups with 6 replicates of 12 birds each and fed for 20 wk. The 6 treatments fed the basal diet supplemented with 0 (control), 20, 40, 80, or 160 mg Zn/kg (ZnSO4·H2O). Dietary supplemental level at 80 mg/kg increased egg production (4.3%) and mass (5.7%), and decreased FCR (2.9%) compared to the basal diet, and these indices increased quadratically with increasing Zn supplemental levels (P < 0.05). The shell breaking strength (15.8%) and fracture toughness (10.6%) were higher with the supplementation of Zn at 80 mg/kg than the basal diet, and increased quadratically with Zn supplementation (P < 0.05). Dietary supplementation of Zn at 80 mg/kg improved shell ultrastructure by increasing total (9.0%) and effective thickness (14.2%) and decreasing mammillary thickness (12.0%), and their responses were quadratic with increasing Zn levels (P < 0.05). The supplementation of Zn affected the calcium contents in plasma, tibias and ulna, ulna phosphorus content, and linear and quadratic effects were observed, and higher values were observed with 160 mg/kg Zn supplementation than control (P < 0.05). The supplemental Zn level at 80 mg/kg increased shell effective thickness in growth stage (P < 0.05), and shell calcium and phosphorus content in initial and growth stages (P < 0.05). Dietary Zn supplementation did not affect the gene expression of Ca2+ transporters in the eggshell gland, but affected the expression of HCO3− exchanger in initial and growth stage (P < 0.05). Overall, dietary Zn supplementation could improve productive performance and shell quality in laying ducks at late phase of production, and calcium metabolism and deposition were modulated by Zn influencing HCO3− secretion and thus affecting shell ultrastructure and quality. A supplemental level of 80 mg/kg Zn in the diet with a basal content of 34.0 mg/kg was optimal, and higher level (160 mg/kg) decreased shell calcium deposition by depressing its metabolism.

This study evaluated the effects of selenium (Se) supplementation in maternal and offspring diets on performance and antioxidant capacity of ducklings aged from 0 to 2 wk. A total of 144 female Longyan duck breeders aged 22-wk were allotted into 2 treatments and fed a control diet or a 0.16 mg Se/kg supplemented diet. At 40-wk, 120 offspring from each treatment were divided into 2 groups, with 6 replicates of 10 birds. Using a 2 × 2 factorial design, ducklings from each maternal dietary treatment were assigned to a control diet or a 0.16 mg Se/kg supplemented diet from hatch to 2-wk. Compared with Se-deficient diet, maternal diet supplemented with 0.16 mg Se/kg increased the BW of hatchlings (P < 0.01). There were interactions between maternal and progeny diet with 0.16 mg Se/kg in BW of ducklings aged 2 wk and BW gain (BWG) as ducklings from maternal Se/progeny none treatment had the lightest BW and BWG (P < 0.01). Maternal diet with 0.16 mg Se/kg decreased plasma concentration of uric acid and insulin-like growth factor 1 (P < 0.01), and progeny diet supplemented with 0.16 mg Se/kg increased the activities of glutathione peroxidase 3 (GPx3) in plasma and glutathione peroxidase 1 in erythrocyte (P < 0.01). Maternal diet with 0.16 mg Se/kg increased (P < 0.05) the hepatic activity of total superoxide dismutase (T-SOD). Progeny diet supplemented with 0.16 mg Se/kg increased (P < 0.01) hepatic activity of GPx3 and decreased (P < 0.01) the hepatic concentration of malondialdehyde. Interactions were detected between maternal and progeny diet with 0.16 mg Se/kg in hepatic activity of T-SOD and maternal and progeny diet supplemented with Se displayed the highest hepatic activity of T-SOD (P < 0.05). Overall, Se supplementation in the diet of duck breeders and offspring increased the antioxidant capacity of ducklings. Maternal Se supplementation increased the BW of hatchlings, whereas maternal and progeny dietary Se supplementation did not affect the BWG of ducklings aged from 0 to 2 wk. Se supplementation with additional 0.16 mg/kg in the diet of duck breeders and offspring displayed beneficial effects particularly on the antioxidant capacity in ducklings.

There is an urgent need to evaluate and introduce alternatives for the unsustainable and traditional feed stuffs in poultry. This study evaluated the effects of graded replacement of soybean meal (SBM) by peanut meal (PNM) on egg production, egg quality, oxidative status, and yolk fatty acid profile in laying ducks. In total, 360 Longyan ducks aged 21 weeks were allocated to five treatments, each containing six replicates of 12 birds. Birds were fed the diets containing PNM replacing 0 (control), 25, 50, 75 or 100% of SBM for 16 weeks. With the increase of PNM level, egg production was improved (quadratic, P 0.05), egg weight and feed consumption were decreased, feed conversion ratio and egg mass were impaired at 100% PNM, and yolk colour was enhanced (quadratic, P 0.05). Plasma malondialdehyde concentration was increased at 100% PNM, while plasma glutathione concentration was decreased (quadratic, P 0.01) as PNM substitution increased. Total cholesterol content in yolk decreased (P 0.01) in response to increased PNM substitution. The contents of saturated fatty acids C20:0 and C22:0 in yolk increased (linear or quadratic, P 0.05) with increased PNM substitution, but the contents of saturated fatty acid C18:0, monounsaturated fatty acid C22:1, and polyunsaturated fatty acids C18:3n-3 and C22:6n-3 in yolk were decreased (linear, P 0.05) as PNM replacement increased. The contents in yolk of polyunsaturated fatty acid C18:2n-6, C20:2n-6, C20:3n-6, C20:4n-6, and total amount of polyunsaturated fatty acids increased with the highest contents obtained at 75% PNM substitution. The ratio between n-6 and n-3 increased (linear, P 0.05) as PNM substitution increased. The transcript abundance in liver of peroxisome proliferators-activated receptors γ and fatty acid synthase showed quadratic (P 0.05) responses with PNM replacement, with the highest expression of both genes being obtained with 75% substitution with PNM. Replacement of dietary SBM with 100% PNM decreased egg production and antioxidant capacity and increased the ratio of omega fatty acid in yolk between n-6 and n-3 in laying ducks. The obtained results indicate that PNM can be used to replace up to 75% of SBM in the diet of laying ducks without negative effects on the egg-laying production or egg quality. The regression model indicated that the maximal egg mass was obtained at no more than 67.6% replacement of SBM with PNM in the diet of laying ducks.

This study aimed to determine the dietary tryptophan (Trp) requirement for laying duck breeders. A total of 504 Longyan duck breeders (body weight: 1.20 ± 0.02 kg) aged 22 wk were randomly allocated to 6 treatments, each with 6 replicates of 14 ducks. During the next 16 wk, birds were fed the basal diet with total Trp contents of 1.00, 2.00, 3.00, 4.00, 5.00 and 6.00 g/kg, respectively. Dietary Trp levels increased egg production, egg mass and feed intake of duck breeders from 22 to 37 wk (P < 0.05), and there were linear and quadratic effects of Trp level (P < 0.05). The feed conversion ratio (FCR) quadratically decreased with dietary Trp levels (P < 0.05). Dietary Trp levels decreased (P < 0.05) egg albumen height and Haugh unit at wk 8 or 12, and the responses were linear and quadratic (P < 0.05). The body weight of breeders, absolute and relative weight of oviduct, number and total weight of preovulatory follicles (POF), and its proportion relative to ovarian weight were increased (P < 0.05), and the responses were linear (P < 0.01) and quadratic (P < 0.001). Ovarian weight increased quadratically (P < 0.05), and the mean weight of POF increased (P < 0.05), linearly and quadratically. The proportion of small yellow follicles relative to ovary weight decreased (P < 0.01) linearly and quadratically. At wk 16 of the trial period, the serum albumin content and alanine aminotransferase activity decreased (P < 0.05) and the creatinine content increased (P < 0.01) linearly and quadratically. The Trp requirements were estimated to be 3.14 g/kg for optimizing egg production, 2.93 g/kg for egg mass, and 2.92 g/kg for FCR. Overall, dietary Trp levels (1 to 6 g/kg) affected productive performance, egg quality, reproductive organ and ovarian follicle development, and serum biochemical indices of layer duck breeders, and a diet containing 2.9 to 3.1 g Trp per kg feed was adequate during the laying period (22 to 37 wk of age).

This study investigated whether dietary lysine (Lys) affects productive performance and expression of genes related to protein and lipid metabolism in laying duck breeders. Longyan duck breeders (n = 540, 19 wk of age) were randomly assigned to 6 groups with 6 replicates of 15 birds each. Breeders were fed diets with 6 total Lys levels (6.4, 7.2, 8.0, 8.8, 9.6, and 10.4 g/kg) for 26 wk duration. Egg production, egg weight, egg mass, feed conversion ratio, hatchability, hatchling weight, albumen weight, eggshell weight, yolk weight, and yolk proportion increased with dietary Lys levels (P0.05). Dietary Lys level had a linear (P0.05) and quadratic (P0.05) effects on maternal hepatic expression of mechanistic target of rapamycin, eukaryotic translation initiation factor 4E binding protein 1, ubiquitin conjugating enzyme E2K (UBE2K), cathepsin B (CTSB), and quadratically (P0.05) increased the concentrations of plasma Lys, leucine, threonine, and tryptophan in duck breeders. In contrast, maternal dietary Lys suppressed expression of proteasome 26S subunit, UBE2K, and CTSB in the liver of hatchlings. Moreover, relative expression of peroxisome proliferator-activated receptors alpha, carnitine palmitoyltransferase 1A, and very low density apolipoprotein-II increased linearly (P0.05) and quadratically (P0.05), and that of VLDL receptor (VLDLR) decreased quadratically (P0.05) in the liver of duck breeders with increasing dietary Lys levels; hepatic triglyceride and cholesterol contents were reduced. Maternal dietary Lys suppressed hepatic expression of VLDLR in the hatchlings. A diet containing 8.6 g Lys/kg promoted protein turnover and lipid metabolism in laying duck breeders, which positively reflected in the productivity and reproductive performance.

This study evaluated the optimal concentrations of dietary ME and CP for the productivity, reproductive performance, and fat deposition in laying duck breeders aged from 29 to 45 wk. Using a 3 × 3 factorial arrangement of treatments, 648 Longyan laying duck breeders with similar BW were randomly assigned to experimental diets of 2,600 (HME = high ME), 2,500 (MME = medium ME), or 2,400 (LME = low ME) kcal of ME/kg, each containing 19% (HCP = high CP), 18% (MCP = medium CP), or 17% (LCP = low CP) CP. Each dietary treatment contained 6 replicates of 12 birds each. Compared with birds fed the LCP diet, the egg production and egg mass were higher in birds fed HCP and MCP (P < 0.01), with better feed conversion (P < 0.01). Interactions were detected between ME and CP levels in egg production, egg mass, and feed conversion ratio as the LMEMCP diet was the best (P < 0.05). The birds fed MME (P < 0.05) had the lowest abdominal fat. The percentage of healthy ducklings was affected by maternal dietary CP (P < 0.05) with the HCP being the highest. The weight of large yellow follicles/ovarian weight was higher in birds fed HCP and MCP (P < 0.05), whereas the weight of small yellow follicles/ovarian weight was higher in birds fed HCP and LCP (P < 0.05). The hepatic transcript abundances of genes for very low density apolipoprotein-II and carnitine palmitoyltransferase-1A (CPT-1A) were lowest in birds fed MCP, whereas the highest abundance of CPT-1A transcripts was found in birds fed MME. These results revealed that the diets containing ME of 12.9 kcal/g protein optimized both egg production and egg mass, while the feed conversion was optimized at 12.8 kcal ME/g protein. Using ME to CP ratio of 12.9 kcal/g protein, i.e., 2,451 kcal ME/kg at 19% CP, maximized the reproductive performance and hatchling outcome of Longyan laying duck breeders.

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 (P0.05) in response to supplementation with 400 and 800 mg/kg of curcumin respectively, compared with 200 mg curcumin/kg group. There was a linear (P0.001) effect of dietary curcumin on relative abundance of SOD1, GPX1, CAT, HO-1, and Nrf2 transcripts, and a quadratic (P0.001) increase in the activities of GSH-Px and T-AOC in jejunal mucosa. The expression of CYP1A4, CYP2D17 increased and CYP1B1, CYP2A6 decreased linearly (P0.001) 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.

This study was aimed at studying use of reduced dietary crude protein (CP) level supplemented with additional amino acids in laying ducks. A total of 720 Jingjiang ducks (50 wk) were randomly assigned to 5 treatments and fed 5 basal diets with CP levels at 17.5, 16.5, 15.5, 14.5, or 13.5%, with additional amino acids added to each diet for 12 wk. Each treatment had 6 replicates of 24 ducks each. Dietary CP levels affected (P 0.05). Ovarian weight, total and mean weight of preovulatory follicles, and total weight of small yellow follicles (SYF) were decreased by dietary CP levels (linear, P

Many studies have shown that productivity, immune system, antioxidant status, and meat and egg quality can be optimized by dietary supplementation with amino acids that are not usually added to poultry diets. Understanding the effects of these amino acids may encourage feed manufacturers and poultry producers to include them as additives. One of these amino acids is tryptophan (Trp). The importance of Trp is directly related to its role in protein anabolism and indirectly related to its metabolites such as serotonin and melatonin. Thus, Trp could affect the secretion of hormones, development of immune organs, meat and egg production, and meat and egg quality in poultry raised under controlled or stressed conditions. Therefore, this review discusses the main roles of Trp in poultry production and its mode (s) of action in order to help poultry producers decide whether they need to add Trp to poultry diets. Further areas of research are also identified to address information gaps.

Optimizing the dietary calcium (Ca) level is essential to maximize the eggshell quality, egg production and bone formation in poultry. This study aimed to establish the Ca requirements of egg-type duck breeders from 23 to 57 weeks of age on egg production, eggshell, incubation, tibial, plasma and ovary-related indices, as well as the expression of matrix protein-related genes. Totally, 450 Longyan duck breeders aged 21 weeks of age were allotted randomly into five treatments, each with six replicates of 15 individually caged birds. The data collection started from 23 weeks of age and continued over the following 35 weeks. The five groups corresponded to five dietary treatments containing either 2.8%, 3.2%, 3.6%, 4.0% or 4.4% Ca. The tested dietary Ca levels increased (linear, P

Heat stress is a major environmental factor contributing to lower production of poultry. The objective of present study was to evaluate the influence of constant or intermittent high temperature on the production performance and redox status of plasma and hypothalamus in laying ducks. A total of 288 weight- and laying-matched laying ducks were randomly assigned to 1 of 4 treatments (each with 6 replicates of 12 birds): control, pair-fed, constant high temperature (24 h, 34 ± 1°C), and intermittent high temperature (10 h, 34 ± 1°C). Blood and hypothalamic tissue samples were collected on days 1, 21, and 55 to determine redox status. Average daily feed intake and egg weight was reduced (P 0.05) among the treatments during the recovery period. Lower (P < 0.05) egg mass was observed in pair-fed and intermittent high-temperature treatment during high-temperature period and in constant high temperature during the recovery period. Haugh units from high temperature-treated ducks were significantly lower than those from control or pair-fed ducks (P < 0.05) during the high-temperature period. Both models of heat exposure decreased plasma concentrations of glutathione (GSH) at day 1, and constant high temperature decreased plasma activity of GSH peroxidase (GSH-PX) at day 21 (P < 0.05). Hypothalamic expression of antioxidant genes GSH reductase (GR) and mitochondrial NADH dehydrogenase subunit (Complex Ι) were decreased by both high-temperature treatments at day 1. Hypothalamic expression of genes for pro-oxidant enzymes cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), and cytochrome P450 7A1 (CYP7A1) were decreased (P < 0.05) by both models of high temperature but transcripts of cyclooxygenase-1 (COX-1) of ducks that were pair-fed or were exposed to constant high temperature were increased at day 21. The transcripts of NADPH oxidase 1 (NOX-1) were decreased at day 1 by both high-temperature treatments (P < 0.05) but increased during the recovery period. These results indicate that, for laying ducks, intermittent high temperature caused much greater negative production performance effects than constant high temperature during high-temperature period, but laying ducks exposed to constant high temperature tend to take longer to recover their production performance. High-temperature stress, either constant or intermittent, altered hypothalamic expression of antioxidation and pro-oxidation genes.

The study investigated the effects of increasing content of corn distillers' dried grains with solubles (DDGS) in the diets of laying ducks on oxidative status, laying performance, egg quality, and egg yolk fatty acid composition. Longyan females (1080) with similar BW at 17 wk of age were randomly assigned to 6 treatment groups, each consisting of 6 replicates of 30 birds. The basal diet (I) was a typical corn-soybean ration while the experimental diets (II to VI) substituted corn DDGS for soybean meal and wheat bran and a small reduction of corn. The level of substitution in diets (II to VI) was 6%, 12%, 18%, 24% and 30%. The experiment lasted for 18 wk. Average egg weight decreased linearly as the level of corn DDGS inclusion increased (P 0.001). Haugh unit, albumen weight, and proportion declined as linear responses to corn DDGS substitution (P 0.05), but yolk color linearly increased (P 0.001); the proportions of oleic (C18:1) and total monounsaturated fatty acids in egg yolk linearly decreased with increasing corn DDGS and many of the key polyunsaturated fatty acids (PUFAs) like linoleic (C18:2n-6), arachidonic (C20:4n-6) and α-linolenic (C18:3n-3) acids linearly increased (P 0.001), but not those of eicosapentaenoic (C20:5n-3) and docoshexaenoic (C22:6n-3) acids. The PUFAs n-6/n-3 ratio linearly increased with increasing corn DDGS level (P 0.001). Increasing corn DDGS linearly increased hepatic expression of GPX1, HO-1, and Nrf2 and hepatic activity of GSH-Px and the liver content of MDA (P 0.001). There were no treatment effects on egg production, egg mass, feed conversion ratio, eggshell thickness, strength, and yolk cholesterol content (P 0.05). In conclusion, the current study indicates that the use of corn DDGS is possible as a replacement, primarily for soybean meal at levels up to 18% in the diets of laying ducks without affecting laying performance, egg quality, and antioxidant status. Increasing amounts of corn DDGS linearly increased egg yolk concentrations of key fatty acids like like C18:2n-6 and C18:3n-3 and the antioxidant enzyme activity of GSH-Px through the Nrf2 pathway to avoid oxidative stress.

This study was conducted to examine five lysine (Lys) levels (0.75, 0.80, 0.85, 0.90, and 0.95%) to estimate the optimal level of Lys for Longyan laying ducks from 22 to 38 wk of age. Nine hundred Longyan ducks aged 22 wk were assigned randomly to the 5 dietary treatments, where each treatment comprised 6 replicate pens with 30 ducks per pen. Lys had no effects on egg production, egg mass, feed conversion ratio, shape index, Haugh unit, yolk colour, yolk weight, or albumen weight, but the egg weight was improved significantly (P

The demand for duck meat, duck eggs, and associated products is increasing each year. Classic and modern selection programs have been applied to enhance the economic traits of ducks to satisfy the requirements of consumers and enhance the incomes of producers. The nutritional requirements of unselected ducks may not be adequate, however, to fulfill the potential productivity performance of modern birds, including both meat-type and egg-type ducks. In particular, an imbalanced diet is associated with low productive performance and signs of nutritional deficiency (if insufficient nutrients are supplied), as well as with high feed costs and manure problems that reflect flock health and welfare (if excessive nutrients are supplied). Thus, the main aim of this review is to summarize the results of previous studies that estimated the nutrient requirements of meat-type and egg-type ducks in order to evaluate current knowledge and to identify further issues that need to be addressed. In addition, the results obtained in previous studies are compared in order to understand how to lower commercial feed costs, fulfill the genetic potential of selected ducks, protect the environment from pollution, and satisfy the welfare and health needs of ducks.

The study investigated whether dietary methionine (Met) affects egg weight and antioxidant status through regulating gene expression of ovalbumin (OVAL), nuclear factor erythroid 2 like 2 (Nrf2) and haem oxygenase 1 (HO-1) in laying duck breeders. Longyan duck breeders (n540, 19 weeks) were randomly assigned to six treatments with six replicates of fifteen birds each. Breeders were fed diets with six Met levels (2·00, 2·75, 3·50, 4·25, 5·00 and 5·75 g/kg) for 24 weeks. The egg weight (g), egg mass (g/d), feed conversion ratio, hatchability, 1-d duckling weight, albumen weight, albumen proportion andOVALmRNA level improved with dietary Met levels, whereas yolk proportion decreased (PPPPPPGPX1),HO-1andNrf2, and quadratically (PGPX1,HO-1andNrf2, increased contents of GPX and T-AOC and reduced carbonylated protein in the brains of hatchlings. Overall, dietary Met concentration affected egg weight and albumen weight in laying duck breeders, which was partly due to gene expression ofOVALin oviduct magnum. A diet containing 4·0 g Met/kg would achieve optimal hepaticGPX1andNrf2expression, maximise the activity of GPX and minimise lipid peroxidation.

The aim of this study was to evaluate the effect of zinc supplementation on productive performance and antioxidant status in laying ducks. Five-hundred-four laying ducks were divided into 7 treatments, each containing 6 replicates of 12 ducks. The ducks were caged individually and fed a corn-soybean meal and wheat bran basal diet (37 mg Zn/kg) or the basal diet supplemented with 15, 30, 45, 60, 75, or 90 mg Zn/kg (as zinc sulfate). During the early laying period of 10 d (daily egg production80%), egg production, daily egg mass, and FCR increased quadratically with increasing dietary Zn levels (P 0.05). The highest egg production and daily egg weight were obtained when 30 or 45 mg Zn/kg diet was supplemented, with lowest FCR. Similarly, the highest egg production and daily egg mass were observed in the group supplemented with 30 or 45 mg Zn/kg during the peak laying period of the subsequent 120 d (daily egg production80%). Average egg weight and feed intake did not differ among the groups of graded Zn supplementation.The egg quality was not affected by dietary Zn, including the egg shape index, Haugh unit, yolk color score, egg composition, and shell thickness. The activities of plasma activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX) increased in a quadratic manner (P 0.001) with increasing supplemental Zn. Plasma concentration of Zn increased quadratically (P 0.05) as dietary Zn increased. The hepatic activity of Cu/Zn-SOD and GSH-PX increased quadratically (P 0.05) with increasing dietary Zn. Plasma Zn concentrations were positively correlated with activities of T-SOD (P 0.05), and positively with plasma Cu. Plasma concentration of reduced glutathione was correlated with plasma Cu. In conclusion, supplementation of Zn at 30 or 45 mg/kg to a corn-wheat bran and soybean basal diet may improve the productive performance and enhance the antioxidant capacity.

This study evaluated the optimal concentrations of dietary Se for the productive and reproductive performance, tibial quality, and antioxidant status in duck breeders aged 23 to 49 wk. In total, 432 Longyan duck breeders aged 22 wk were allotted randomly to 6 treatments, each with 6 replicates of 12 individually caged birds. The experiment lasted for 27 wk, and birds were fed corn-soybean meal-based diets containing 0.11, 0.19, 0.27, 0.35, 0.43, or 0.51 mg Se/kg, respectively. The tested dietary Se levels did not affect egg production and tibial quality of duck breeders. The Se contents of the shell, yolk or albumin, whole egg, and the fertility of set eggs increased in a linear and quadratic manner (P 0.19 mg Se/kg diet enhanced the antioxidant capacity in breeders and their offspring. The regression model indicated that dietary Se levels 0.19, 0.27, 0.28, 0.24, and 0.30 mg/kg are optimal levels to obtain maximum Se deposition efficiency in eggs, egg fertility, Gpx1 activity in erythrocytes and liver in duck breeders, and plasma activity of Gpx3 in newly hatched ducklings, respectively.

The presence of aflatoxin B1 (AFB1) in poultry diets decreases the hatchability, hatchling weight, growth rate, meat and egg production, meat and egg quality, vaccination efficiency, as well as impairing the feed conversion ratio and increasing the susceptibility of birds to disease and mortality. AFB1 is transferred from poultry feed to eggs, meat, and other edible parts, representing a threat to the health of consumers because AFB1 is carcinogenic and implicated in human liver cancer. This review considers how AFB1 produced by Aspergillus flavus and Aspergillus parasiticus strains can affect the immune system, antioxidant defense system, digestive system, and reproductive system in poultry, as well as its effects on productivity and reproductive performance. Nutritional factors can offset the effects of AFB1 in poultry and, thus, it is necessary to identify and select suitable additives to address the problems caused by AFB1 in poultry.

This study aimed to establish the arginine requirements of Longyan ducks from 17 to 31 wk of age based on egg production, egg quality, plasma, and ovarian indices, as well as the expression of vitellogenesis-related genes. In total, 660 Longyan ducks with similar body weight at 15 wk of age were assigned randomly to 5 treatments, each with 6 replicates of 22 birds, and fed a corn-corn gluten meal basal diet (0.66% arginine) supplemented with either 0, 0.20%, 0.40%, 0.60%, or 0.80% arginine. Dietary arginine did not affect egg production by laying ducks, but it increased (linear, P < 0.01) the egg weight at 22 to 31 and 17 to 31 wk of age. Dietary arginine increased the yolk color score (linearly, P < 0.05) and the yolk percentage (quadratic, P < 0.05), where the maximum values were obtained with 1.26% arginine. Dietary arginine affected the total shell percentage and shell thickness, with the highest values using 1.46% arginine (P < 0.01). The weight and number of small yellow follicles (SYFs) increased (quadratic, P < 0.05) with the dietary arginine level and there was a quadratic response (P < 0.05) in terms of the SYFs weight/ovarian weight; the highest values were obtained in ducks fed 1.26% arginine. The plasma arginine concentration exhibited a quadratic (P < 0.05) response to dietary arginine. The plasma progesterone concentration decreased (linear, P < 0.05) as dietary arginine increased. The mRNA abundance of the very low density lipoprotein receptor-b increased in the second large yellow follicle membranes (quadratic, P < 0.05) with the dietary arginine level, where the highest value occurred with 1.26% arginine. According to the regression model, the dietary arginine requirements for Longyan laying ducks aged 17 to 31 wk are 1.06%, 1.13%, 1.22%, and 1.11% to obtain the maximum yolk percentage, SYFs number, SYFs weight, and SYFs weight/ovarian weight, respectively.

The current research was to study the efficacy of L-methionine in comparison to DL-methionine in Cherry Valley ducks. A total of 1080 1-d-old Cherry Valley male ducks were allotted to nine groups with six replicate pens of 20 birds each according to a completely randomized design. Ducks were reared in coops (or on floor). The trials last 35 days and divided to two phases (0–14 d and 15–35 d). During the starter phase, ducks were fed a basal diet (Met, 0.30%) or supplemented with DL-Met or L-Met at 0.05%, 0.10%, 0.15%, or 0.2% of feed. During the growth phase, ducks were fed a basal diet (Met, 0.24%) or supplemented with DL-Met or L-Met at 0.04%, 0.08%, 0.12%, or 0.16% of feed. The results showed that dietary DL-Met or L-Met supplementation affected the growth performance of ducks in starter and whole phases(P < 0.05), both linearly and quadratically increased the body weight of ducks at 14 and 35 d of age, the average daily gain (ADG) of the starter and whole period, the feed intake and feed ratio during the starter phase (L < 0.05; Q < 0.05). No significant difference of carcass quality of ducks was found among groups, except the L-Met supplementation linearly and quadratically increased the leg ratio of eviscerated ducks (L < 0.001; Q < 0.001). Dietary DL-Met or L-Met supplementation linearly and quadratically increased the score of back feather of ducks at 35 d of age (L < 0.05;Q < 0.05). Besides, compared with DL-Met, the efficacy of L-Met was 110.8% (ADG in starter phase, R2=0.79) and 127.8% (feed ratio in starter phase, R2=0.79). Overall, dietary L-Met supplementation can affect the growth performance of ducks, especially at the starter phase, and the efficacy in ADG and feed ratio were 110.8% and 127.8% respectively.

To establish the dietary Ca requirements for laying ducks during their peak laying period, 5 Ca levels (2.8, 3.2, 3.6, 4.0, and 4.4%) were used, and laying performance, eggshell quality, serum variables, and bone quality were examined. A total of 1,620 Longyan shelducks with similar BW at 20 wk of age were fed for 13 wk in 5 treatment groups, each with 4 replicates of 81 birds. Dietary Ca increased egg production and egg mass (linear, P

Structure and design were proposed for a kind of novel multifunctional M × N microring array side-coupled Mach-Zehnder interferometer (MZI) electrooptic switch/ filter. The device can be operated as a notch or bandpass filter by applying voltages on the under-reference MZI arm, and it can also serve as an optical switch by applying voltage on microrings. The dependence relations of the device's performances on RSA size (M and N) are thoroughly analyzed and concluded. As a switch, for making driving voltages under both operation states below 5 V, N and M should be within the range of 2-8. For the seven switches (M = 1, 8 ≥ N ≥ 2), their insertion losses are within 0.85-0.35 dB at bar state and within 0.14-1.70 dB at cross state; the crosstalk are within -20.79- -31.11 dB at bar state and within -13.86--20.36 dB at cross state; and their 3-dB electrical bandwidths are 18.5-30.5 GHz, whereas their 3-dB optical bandwidths for ports 1 and 2 are 18.1-40.0 GHz and 19.0-55.0 GHz, respectively. In addition, the needed energy per bit under 10-GHz switching operations is within 0.092-0.697 pJ. Therefore, the proposed multifunctional device shows potential applications, including filtering, routing, and switching, in optical networks-on-chip.

The objective of this study is to build energy models for predicting nitrogen-corrected apparent metabolizable energy (AMEn) requirements of different categories of Chinese Yellow broiler breeder hens during egg-laying period. Data for modelling were generated from published research papers, unpublished results from our research group and some production data supplied by compaines. There are dozens of breeds of Chinese Yellow broiler breeders in China, therefore, hens were alloted into 3 categories: heavy, medium and light body weight (BW, kg). We reffered to published articles to determine coefficients of AMEn requirement for maintenance (AMEnm) and gain (AMEng) respectively. The moldels of AMEn for egg production (AMEnp) were built and then daily intake of AMEn (AMEni, kcal/d/hen) models acquired according to factorial approach that AMEni = AMEnm + AMEng +AMEnp. Heavy BW: AMEni = 101 × BW0.75 + 5.33 × average daily gain (ADG, g) + 2.55 × egg mass (EM, g/d/hen) (P < 0.001; R(2) = 0.711); medium BW: AMEni = 101 × BW(0.75) + 5.33 × ADG + 2.94 × EM (P < 0.01; R(2) = 0.586) and light BW: AMEnp = 126 × BW(0.75) + 5.33 × ADG + 1.88 × EM (P < 0.001; R(2) = 0.605). The AMEn requirments (kcal/kg diet) for each category of hens were determined with 2678, 2628 and 2583 kcal/kg for heavy, medium and light BW respectively, which are the mean values of dietary AMEn from many published articles divided into 3 categories accordingly. The AMEni requirements acquired from the models were 348, 303 and 210 kcal/d/hen for heavy, medium and light BW respectively. These models were evaluated by simulation of experiments reported in the literature, and comparison of simulated to measured requirements, which showed that models provided good adjustments. Performance trials will be conducted to further evaluate these models.

A total of 1,200 LinNan Chinese color-feathered chicks were used to study the effects of methionine source [DL-2-hydroxy-4-methylthio-butanoic acid (HMTBa) or DL-methionine (DLM)] and dietary crude protein (CP) level on growth performance, carcass traits, and whole-body nitrogen and fat retention. The trial was designed as a 2x2 factorial arrangement, including two CP levels (adequate and low) and two methionine sources (HMTBa and DL-methionine). Diets were formulated for three phases, starter (0-21 d), grower (21-42 d), and finisher (42-63 d). Chicks fed HMTBa had higher daily gain and improved feed efficiency than DLM during the grower phase (p 0.05). Chicks fed low-CP diets grew slower, used feed less efficiently during the grower, finisher phase and overall. On d 42, regardless of dietary CP levels, birds fed HMTBa had higher carcass weights, breast and thigh weights than DLM-fed birds (p

The study was designed to evaluate the effects of different dietary levels of rice bran (RB) in laying duck diets on performance, egg quality, oxidation status, egg yolk fatty acid composition, and hepatic expression of fatty acid metabolism-related genes. Longyan females (1080) with similar BW at 19 wk of age were randomly assigned to 6 dietary treatments, each consisting of 6 replicates of 30 birds. The basal diet (I) was a typical corn-soybean ration while the experimental diets (II to VI) substituted RB for corn and wheat bran and a small reduction of soybean meal. The level of substitution in diets (II to VI) was 6%, 12%, 18%, 24%, and 30%, respectively. The experiment lasted for 12 wks. Average egg weight and daily egg mass decreased linearly as the level of RB inclusion increased (P0.001) and feed conversion ratio linearly increased (P0.001). The proportions of C14:0 and C18:0 and total saturated fatty acids (SFA) in egg yolk linearly decreased with increasing RB, and many of the key polyunsaturated fatty acids (PUFA), like C18:2 n-6 and C18:3 n-3, linearly increased (P0.001), but not those of C20:5 n-3 and C22:6 n-3. There were linear decreases (P0.001) in hepatic abundance of FAS and SREBP1 transcripts, with a substantial reduction to about 30% those of ducks fed the control diet; there were no treatment effects on productive performance, eggshell thickness, strength, Haugh unit, antioxidation status, and egg yolk cholesterol or triglyceride content (P0.05). In conclusion, the current study suggests that ducks from 19 to 31 wk could be fed diets with up to about 18% RB without effect on the number of eggs produced, egg quality, and oxidative status. Increasing amounts of RB linearly increased egg yolk concentrations of key fatty acids like C18:2 n-6 and C18:3 n-3 and decreased the hepatic abundance of FAS and SREBP-1 transcripts.

Birdsfoot trefoil (Lotus corniculatus) increases milk yield of dairy cows. An indoor feeding experiment using Friesian dairy cows in mid lactation was conducted to determine what proportions of the milk yield and composition changes were due to the condensed tannins (CT) in Lotus, and what proportions were due to factors associated with legumes (higher herbage intake and forage quality). Cows were fed either perennial ryegrass or Lotus, and were also drenched with either polyethylene glycol (PEG) to block the action of CT, or water. Milk yields (kg/cow/d) were higher on Lotus (21.24) than on Lotus+PEG (18.61), ryegrass (15.53) or ryegrass+PEG (15.49) indicating that CT contributed to 46% of the increased milk yield that resulted from feeding Lotus rather than ryegrass. CT had no effect on intake, but contributed to increased milk protein concentration, increased efficiency and decreased milk fat concentration.

Device architecture and design scheme of an N × N scalable electrooptic (EO) routing switch array (RSA) are proposed using electric-field-induced EO polymeric microrings. The basic 2 × 2 /cross/bar EO switching element is optimized under 1550-nm wavelength, and the ring radius is only 13.76 μm with -4 dB/cm bending loss. The basic element reveals a free spectral range (FSR) of 17 nm, a switching voltage of 5 V, and response times of 70/140 ps, and the crosstalk under cross and bar states are about -28.8 and -39.9 dB, respectively. Using 2 × 2 switching elements, 4 × 4, 8 × 8, 16 × 16, and 32 × 32 RSAs are presented, under all routing paths, their maximum insertion losses are 2.57, 5.19, 5.99 and 7.59 dB, respectively, and their maximum crosstalk are - 28.7, -28.7, - 26.27 and -25.07 dB, respectively. Universal structure, routing scheme, electrical/optical responses, and dynamic power consumption (PC) of N × N RSA are then demonstrated, and dependence relations between routing performances and the RSA size N are achieved through data fitting. Comparisons with other reported passive/active routers/switches confirm that, due to superiority on fewer rings, picosecond faster response speed, zero static PC, and lower insertion loss and crosstalk, this polymer-based routing scheme can be a good candidate in on-chip optical systems.