Zinc glycine chelate ameliorates DSS-induced intestinal barrier dysfunction via attenuating TLR4/NF-κB pathway in meat ducks.

BACKGROUND: Zinc glycine chelate (Zn-Gly) has anti-inflammation and growth-promoting properties; however, the mechanism of Zn-Gly contribution to gut barrier function in Cherry Valley ducks during intestinal inflammation is unknown. Three-hundred 1-day-old ducks were divided into 5 groups (6 replicates and 10 ducks per replicate) in a completely randomized design: the control and dextran sulfate sodium (DSS) groups were fed a corn-soybean meal basal diet, and experimental groups received supplements of 70, 120 or 170 mg/kg Zn in form of Zn-Gly. The DSS and treatment groups were given 2 mL of 0.45 g/mL DSS daily during d 15-21, and the control group received normal saline. The experiment lasted 21 d. RESULTS: Compared with DSS group, 70, 120 and 170 mg/kg Zn significantly increased body weight (BW), villus height and the ratio of villus to crypt, and significantly decreased the crypt depth of jejunum at 21 d. The number of goblet cells in jejunal villi in the Zn-Gly group was significantly increased by periodic acid-Schiff staining. Compared with control, the content of intestinal permeability marker D-lactic acid (D-LA) and fluxes of fluorescein isothiocyanate (FITC-D) in plasma of DSS group significantly increased, and 170 mg/kg Zn supplementation significantly decreased the D-LA content and FITC-D fluxes. Compared with control, contents of plasma, jejunum endotoxin and jejunum pro-inflammatory factors IL-1ß, IL-6 and TNF-α were significantly increased in DSS group, and were significantly decreased by 170 mg/kg Zn supplementation. Dietary Zn significantly increased the contents of anti-inflammatory factors IL-10, IL-22 and sIgA and IgG in jejunum. Real-time PCR and Western blot results showed that 170 mg/kg Zn supplementation significantly increased mRNA expression levels of CLDN-1 and expression of OCLN protein in jejunum, and decreased gene and protein expression of CLDN-2 compared with DSS group. The 120 mg/kg Zn significantly promoted the expressions of IL-22 and IgA. Dietary Zn-Gly supplementation significantly decreased pro-inflammatory genes IL-8 and TNF-α expression levels and TNF-α protein expression in jejunum. Additionally, Zn significantly reduced the gene and protein expression of TLR4, MYD88 and NF-κB p65. CONCLUSIONS: Zn-Gly improved duck BW and alleviated intestinal injury by regulating intestinal morphology, barrier function and gut inflammation-related signal pathways TLR4/MYD88/NF-κB p65.

Effects of different dietary vitamin D combinations during the grower phase and the feed restriction phase on growth performance and sternal morphology, mineralization, and related genes expression of bone metabolism in Pekin ducks.

Our study aimed to investigate the effects of different dietary vitamin D (VD) combinations during the grower (1-32 d of age) and feed restriction (33-52 d of age) phases on growth performance. We also evaluated sternal morphology, mineralization, and related genes expression of bone metabolism as well as absorption of calcium and phosphorous in duodenal mucosa and kidney in Pekin ducks. During the grower phase, we used 2 VD regimes (Group A: 3,160 IU/kg VD3; Group B: 400 IU/kg VD3 + 69 µg/kg 25-OH-D3). Each dietary treatment had 50 replicate pens of 10 ducks per pen. During the feed restriction phase, 30 replicate pens selected from Group A and Group B, repetitively, were redivided into 5 different dietary VD regimes to form a 2 × 5 experimental design. Each group consisted of 6 replicates, each with 10 ducks. During the feed restriction phase, we evaluated 5 different dietary VD combinations were as follows: T1: 2,000 IU/kg VD3 ; T2: 5,000 IU/kg VD3; T3: 3,620 IU/kg VD3 + 34.5 µg/kg 25-OH-D3; T4: 2,240 IU/kg VD3 + 69 µg/kg 25-OH-D3; T5: 1,800 IU/kg VD3 + 80 µg/kg 25-OH-D3). Results showed that Group B combinations with T5 had a better growth performance and breast meat deposition (P < 0.1). Regardless of 5 dietary VD regimes during the feed restriction phase, Group B significantly increased (P < 0.05) 52 d sternal depth and tended to increase (P < 0.1) 52 d sternal defatted weight, ash content, and phosphate (P) content of ducks. A significant interactive effect (P < 0.05) was observed on the mRNA abundance of DMP1 and Sost1 as well as RANKL/OPG in sternum and of VDR in duodenal mucosa of ducks at 52 d of age between dietary VD combinations during 2 phases. These results indicated that dietary VD regimes during the grower phase could affect the effectiveness of dietary VD regimes during the feed restriction phases; Dietary VD combinations of both phases could affect the genes expression of bone formation and the absorption as well as reabsorption of calcium and phosphorus in duodenum and kidney.

The effect of epigallocatechin gallate on laying performance, egg quality, immune status, antioxidant capacity, and hepatic metabolome of laying ducks reared in high temperature condition.

Epigallocatechin gallate (EGCG) is a main component in green tea extract, which possesses multiple bioactivities. The present research studied the effects of EGCG on the laying performance, egg quality, immune status, antioxidant capacity, and hepatic metabolome of Linwu laying ducks reared under high temperature. A total of 180 42-w-old healthy Linwu laying ducks were allocated into control or EGCG-treated groups. Each treatment had 6 replicates with 15 ducks in each replicate. Diets for the two groups were basal diets supplemented with 0 or 300 mg/kg EGCG, respectively. All ducks were raised in the high temperature condition (35 ± 2 °C for 6 h from 10:00 to 16:00, and 28 ± 2 °C for the other 18 h from 16:00 to 10:00 the next day) for 21 days. Results showed that EGCG increased the egg production rate (p = 0.014) and enhanced the immunocompetence by improving serum levels of immunoglobulin A (p = 0.008) and immunoglobulin G (p = 0.006). EGCG also fortified the antioxidant capacity by activating superoxide dismutase (p = 0.012), catalase (p = 0.009), and glutathione peroxidase (p = 0.021), and increasing the level of heat-shock protein 70 (p = 0.003) in laying ducks' liver. At the same time, hepatic metabolomics result suggested that EGCG increased the concentration of several key metabolites, such as spermidine (p = 0.031), tetramethylenediamine (p = 0.009), hyoscyamine (p = 0.026), ß-nicotinamide adenine dinucleotide phosphate (p = 0.038), and pantothenic acid (p = 0.010), which were involved in the metabolic pathways of glutathione metabolism, arginine and proline metabolism, ß-alanine metabolism, and tropane, piperidine, and pyridine alkaloid biosynthesis. In conclusion, 300 mg/kg dietary EGCG showed protection effects on the laying ducks reared in high temperature by improving the immune and antioxidant capacities, which contributed to the increase of laying performance of ducks. The potential mechanism could be that EGCG modulate the synthesis of key metabolites and associated metabolic pathways.

Effect of Bacillus toyonensis BCT-7112T supplementation on growth performance, intestinal morphology, immune-related gene expression, and gut microbiome in Barbary ducks.

This study aimed to investigate the effect of Bacillus toyonensis BCT-7112T supplementation on growth performance, intestinal morphology, immune-related gene expression, and the cecal microbiota of meat ducks. A total of 150 one-day-old male Barbary ducks were divided into 3 groups with 5 replicates (n = 10 ducks per replicate) by completely randomized design and offered diets supplemented with the commercial product Toyocerin (containing 1 × 109B. toyonensis BCT-7112T viable spores/g product) at the levels of 0, 500, or 1,000 mg/kg (0, 500, or 1,000 ppm), respectively, for 8 wk. The results showed that although ducks in the 500 ppm B. toyonensis BCT-7112T group displayed numerically better values (e.g., weight gain and feed conversion ratio) than those in the control group, the growth performance of ducks fed diets supplemented with B. toyonensis BCT-7112T did not differ significantly from that of the control group (P > 0.05). There were no significant differences in the intestinal mucosal morphology of ducks across the experimental groups (P > 0.05). However, ducks in the 500 ppm B. toyonensis BCT-7112T group showed a trend of greater values, for example, villus height per crypt depth of duodenum (P = 0.16) and ileum (P = 0.12) compared with those in the control group. The relative expression of immune-related genes, for example, interferon (IFN) and interleukin-6 (IL-6) in the meat duck spleen was significantly lower in both B. toyonensis BCT-7112T groups at 14 d and 35 d than in the control group (P < 0.05). Beta diversity analysis of the cecal microbiota of ducks in either the 500 ppm or the 1,000 ppm B. toyonensis BCT-7112T group showed to have higher diversity than that in the control group, where at the phylum level, Bacteroidetes was the most abundant, followed by Firmicutes, and at the genus level, Bacteroides, Fusobacterium, and Ruminococcaceae were the top 3 most abundant genera. In conclusion, our study demonstrates that 500 ppm supplementation with B. toyonensis BCT-7112T in duck diets can reduce proinflammatory cytokine gene expression, improve immunological function, and increase the variety of microbial communities in the ceca of meat-type ducks.

Organic zinc glycine chelate is better than inorganic zinc in improving growth performance of cherry valley ducks by regulating intestinal morphology, barrier function, and the gut microbiome.

Zinc (Zn) is an essential trace element that has physiological and nutritional functions. However, excessive use of Zn can lead to waste of resources. In this study, we compared the effects of inorganic (ZnSO4) and organic Zn glycine chelate (Zn-Gly) on the growth performance, intestinal morphology, immune function, barrier integrity, and gut microbiome of Cherry Valley ducks. We randomly divided 180 one-day-old male meat ducks into three groups, each with six replicates of 10 birds: basal diet group (CON), basal diet with 70 mg Zn/kg from ZnSO4 (ZnSO4 group), and basal diet with 70 mg Zn/kg from Zn-Gly (Zn-Gly group). After 14 and 35 d of feeding, birds in the Zn groups had significantly increased body weight and average daily gain (ADG), decreased intestinal permeability indicator d-lactate, improved intestinal morphology and barrier function-related tight junction protein levels, and upregulated mucin 2 and secretory immunoglobulin A levels compared to the control (P < 0.05). Additionally, compared to the ZnSO4 group, we found that supplementation with Zn-Gly at 70 mg/kg Zn resulted in the significant increase of body weight at 35 d, 1 to 35 d ADG and average daily feed intake, villus height at 14 and 35 d, secretory immunoglobulin A and immunoglobulin G at 14 d, and mucin 2 mRNA level at 14 d (P < 0.05). Compared with the control group, dietary Zn had a significant effect on the gene expression of metallothionein at 14 and 35 d (P < 0.05). 16S rRNA sequencing showed that Zn significantly increased alpha diversity (P < 0.05), whereas no differences in beta diversity were observed among groups (P > 0.05). Dietary Zn significantly altered the cecal microbiota composition by increasing the abundances of Firmicutes, Blautia, Lactobacillus, Prevotellaceae NK3B31, and [Ruminococcus] torques group and reducing that of Bacteroides (P < 0.05). Spearman correlation analysis revealed that the changes in microbiota were highly correlated (P < 0.05) with growth performance, intestinal morphology, and immune function-related parameters. Taken together, our data show that, under the condition of adding 70 mg/kg Zn, supplementation with Zn-Gly promoted growth performance by regulating intestinal morphology, immune function, barrier integrity, and gut microbiota of Cherry Valley ducks compared with the use of ZnSO4 in feed.

Zinc (Zn) is an essential trace element that is required for physiological and nutritional functions, but excessive use of Zn can lead to environmental pollution. Few studies have directly compared the impact of different Zn sources on growth performance and intestinal barrier function in Cherry Valley ducks. This study was conducted to investigate the effects of two sources of Zn (inorganic ZnSO4 or organic Zn glycine chelate, Zn-Gly) on growth performance, intestinal morphology, barrier function, and gut microbiome of ducks. Compared to the ZnSO4 group, we found that supplementation with Zn-Gly resulted in the significant increase of body weight at 35 d, 1 to 35 d average daily gain and average daily feed intake, villus height at 14 and 35 d, secretory immunoglobulin A and immunoglobulin G at 14 d, and mucin 2 mRNA level at 14 d. At the genus level, the relative abundance of Blautia was higher in the Zn-Gly group than that in the control and ZnSO4 group. Therefore, Zn-Gly supplementation at 70 mg/kg Zn had positive effects in promoting growth performance by regulating intestinal morphology, barrier function, and gut microbiota of ducks when compared with the same dosage use of ZnSO4 in feed.

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

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

Effects of Dietary Milk Thistle (Silybum marianum) Supplementation in Ducks Fed Mycotoxin-Contaminated Diets.

The medicinal plant milk thistle (Silybum marianum) has been widely used due to its hepatoprotective properties. The main objective of our study was to investigate the health protective effects of dietary milk thistle seed (MS), oil (MO), and seed cake (MSC) in ducks fed diets naturally contaminated with deoxynivalenol (DON; 3.43-3.72 mg/kg feed) and zearalenone (ZEN; 0.46-0.50 mg/kg feed). Female White Hungarian ducks were randomly allocated to four dietary treatments consisting of the control diet (C), the control diet supplemented with 0.5% MS, 0.5% MSC, or 0.1% MO. The feeding of experimental diets did not result in mortality cases, clinical signs of mycotoxicosis, or in differences of clinical chemistry values of blood serum. The positive effect of MO on vacuolar hepatocyte degeneration exceeded that of the MSC on d14 and both MS and MSC on d42. Each treatment was equally effective in the decrease of the severity of solitary cell death and infiltration of lympho- and histiocytes in the liver on d28 as well as in the prevention of lymphocyte depletion in the spleen and bursa of Fabricius on d14. In conclusion, the applied treatments have been proven effective in the prevention of histopathological changes caused by DON and ZEN.

Feeding Laying Ducks Eucommia ulmoides oliv. Leaves Increases the n-3 Fatty Acids Content and Decreases the n-6: n-3 PUFA Ratio in Egg Yolk without Affecting Laying Performance or Egg Quality.

The objective was to determine the effects of supplementing duck diets with Eucommia ulmoides oliv. leaf powder (EUL). Laying ducks (n = 480) were randomly allocated into 4 experimental treatments and fed diets containing 0, 1, 2, or 4% EUL. Dietary inclusion of EUL had no effect (p > 0.05) on laying performance or egg quality, but linearly increased (p < 0.05) total plasma protein, globulin, and HDL-C concentrations with concurrent reductions (p < 0.05) in plasma concentrations of cholesterol and LDL-C. Eggs laid by ducks receiving EUL had yolks with linearly higher phenolic concentrations (p < 0.05) but lower cholesterol concentrations (p < 0.05). EUL supplementation in duck diets significantly reduced n-6: n-3 PUFA ratio by enriching n-3 fatty acids in yolks (p < 0.05) with no changes in n-6 PUFA (p >0.05).

Effects of rosemary extract supplementation in feed on growth performance, meat quality, serum biochemistry, antioxidant capacity, and immune function of meat ducks.

This study aimed to investigate the effects of diets supplemented with different levels of rosemary extract (RE) on the growth performance, meat quality, serum biochemistry, antioxidative capacity, and immunological capacity of Cherry Valley meat ducks. A total of 525 healthy Cherry Valley female meat ducks at 1 d of age were selected for this study. Ducks were randomly divided into 5 treatments with 7 replicates per treatment, and each replicate had 15 ducks. All replicates were randomly assigned to treatments. The study was designed as a dose response experiment. Treatment 1 (CON) was fed with the basal diet, and Treatment 2 to 5 (RE250, RE500, RE750, RE1000) were fed with the basal diet supplemented with 250, 500, 750, and 1,000 g/t RE, respectively. The whole experiment lasted 42 days with early stage (1-21 d) and late stage (22-42 d). Results showed that during 22 to 42 d, ducks that were fed over 500 g/t RE had significantly lower feed gain ratio than the ones in CON (P = 0.006). In addition, ducks in RE750 had significantly lower L* and a* in leg muscle compared with the ones in CON (P < 0.05). Besides, ducks that were fed between 250 and 750 g/t RE had significantly lower total protein level in serum compared with the ones in CON (P = 0.005). Ducks in RE250 and RE750 had significantly lower albumin, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol levels in serum compared with the ones in CON and RE1000 (P < 0.05), and significant quadratic relationships were noticed between albumin, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol and dietary RE level (P < 0.05). Moreover, ducks that were fed between 500 and 750 g/t RE had significantly higher levels of interleukin-2 in serum compared to the ones in CON and RE1000 (P = 0.003). Ducks in RE250 and RE750 had significantly higher levels of immunoglobulin G in serum compared to the ones in CON and RE1000 (P < 0.001). Ducks that were fed over 500 g/t RE had significantly higher levels of immunoglobulin A in serum compared to the ones in CON (P = 0.001). Finally, ducks that were fed between 500 and 750 g/t RE had significantly higher serum levels of glutathione peroxidase, superoxide dismutase, catalase, and total antioxidant capacity (P < 0.05) compared to the ones in CON. Ducks that were fed over 250 g/t RE had significantly lower serum level of malondialdehyde compared to the ones in CON (P = 0.020). Collectively, dietary supplementation of RE improved the growth performance and meat qualities of meat ducks during 22 to 42 d, which were possibly associated with the antioxidative and anti-inflammatory effects of RE. Based on the serum antioxidative and immunological parameters, we suggested that 500 to 750 g/t was the optimal supplementation rate for RE in diets for meat ducks aged 22 to 42 d.

Effects of dietary organic acids and probiotics on laying performance, egg quality, serum antioxidants and expressions of reproductive genes of laying ducks in the late phase of production.

Five hundred and forty Cheery Valley ducks were used to investigate the effects of dietary supplementation of acidifier and compound probiotics, individually or in combination, on production performance, egg quality, immune and oxidative status, expression of reproductive, and calcium binding related genes from 42 wk to 48 wk of age. Ducks were randomly allocated to 9 treatment groups with 6 replicates and 10 ducks per replicate for each group. A 3 × 3 factorial arrangement, with 3 dietary inclusion levels of acidifier and probiotics (0, 2, and 3 g/kg acidifier; 0, 1, and 2 g/kg probiotics) were used. The acidifier used was mainly consisted of Benzoic acid, Fumaric acid, phosphoric acid, and formic acid. The main components of the probiotics were Bacillus subtilis and Clostridium butyricum. Dietary supplementation of probiotics improved the daily feed intake, egg production rate, and body weight of ducks (P < 0.05), and diet acidifier also increased the daily feed intake compared to the control (P < 0.01). Egg quality was improved by diet inclusion of probiotics, including Haugh unit, albumen height, egg shape index (P < 0.01), and eggshell hardness (P = 0.05). A significant increase in Haught unit and yolk weight was observed in ducks fed diet added with acidifier (P < 0.05). Acidifier supplementation reduced the total antioxidant capacity (T-AOC), immunoglobulin A (IgA), and IgG content and the catalase (CAT) activity in the serum (P < 0.05), in accompanied with an increased malondialdehyde (MDA) concentration (P < 0.05). Serum total superoxide dismutase (T-SOD) activities were improved by dietary inclusion of probiotics (P < 0.05). There was an interaction effects on serum IgA and IgG contents between acidifier and probiotics (P < 0.05). Diet supplementation of probiotics improved the ovary follicle-stimulating hormone receptor (FSHR) and estrogen receptor (ER) gene expressions (P < 0.01), while dietary acidifier reduced the transcription levels of FSHR and luteinizing hormone receptor (LHR) (P < 0.01) in ovary. In the uterus of the oviduct, expressions of FSHR, and carbonic anhydrase 2 (CA2) were also increased by diet probiotics (P < 0.01), and diet acidifier reduced the gene expressions of calbindin-D28k (CaBP-D28k) and CA2 (P < 0.05). Significant interaction effects between diet acidifier and probiotics were obtained on gene expressions of FSHR, LHR, and ovalbumin (OVAL) in the ovary (P < 0.05), and LHR, CaBP-D28k, and CA2 (P < 0.05) in the uterus. It can be concluded that production performance and egg quality of laying ducks can be improved in the late phase of reproduction by dietary inclusion of probiotics, while the organic acid mixture caused a decline in serum antioxidant and immune capacity of the ducks.

Effect of a probiotic containing lactobacilli and bifidobacteria on the metabolic processes, litter microbiocenosis, and production indicators of broiler Pekin ducklings.

Background and Aim: The use of antibiotics is prohibited in poultry feeding in many countries worldwide, which has resulted in the emergence of antibiotic-resistant bacteria. Therefore, probiotic supplements are a good alternative in these circumstances. Probiotics, including Bifidobacterium adolescentis and Lactobacillus acidophilus, can reduce the development of resistance and stimulate the growth of broiler ducklings. This study aimed to evaluate properties of the probiotic supplement containing these bacteria. Materials and Methods: We studied the response of broiler ducklings to the addition of a dietary probiotic supplement containing lactobacilli and bifidobacteria until they reached 7 weeks of age. All birds participating in the experiment received probiotic supplements on days 1-7, 15-21, 29-35. The state of the ducklings was assessed on day 21. At the age of 21 and 42 days, 4-5 ml of blood was drawn from the wing vein of 10 randomly selected birds (5 in each group). Blood samples were analyzed for total protein, concentration of glucose, hemoglobin, calcium and inorganic phosphorus, as well as the number of erythrocytes and leukocytes. Enzymatic calorimetric method, molybdate method, and haemocytometry according to Nutt method and haemoglobin cyanide method were used to analyze blood samples. Results: The live weight of the experimental ducklings increased by 5.0%, showing a positive effect of probiotic supplementation, whereas their feed consumption per kilogram of weight gain decreased. Their hemoglobin content and red blood cell count increased. Although the number of lactobacilli and bifidobacteria increased, the number of Escherichia coli cells decreased 2.15-fold (p<0.05). The addition of the probiotic supplement contributed to improving the digestibility of protein and fat by 1.6%, fiber by 3.4%, and nitrogen-free extractive substances by 4.7%. The broiler ducklings had high meat quality indicators, including dressing percentage, which increased by 5.4%, whereas the fat content decreased by 1.3%. Conclusion: The introduction of the probiotic supplement in the diet of broiler ducklings improved their growth indicators and increased the number of lactobacilli and bifidobacteria while decreasing the number of E. coli cells in the intestine. It not only improved the meat quality but also increased the profit from $0.392 per bird in the control group to $0.472 per bird in the experimental group. Therefore, this probiotic supplement is a good alternative for raising ducklings in large enterprises and farms. The study limitations may be that the results are only applicable to broiler ducklings. The use of lactobacilli may yield different results in other bird breeds or broiler ducklings in different age groups.

Effect of Dietary Zinc Methionine Supplementation on Growth Performance, Immune Function and Intestinal Health of Cherry Valley Ducks Challenged With Avian Pathogenic Escherichia coli.

This study was carried out to evaluate the effects of supplemental zinc methionine (Zn-Met) on growth performance, immune function, and intestinal health of meat ducks challenged with avian pathogenic Escherichia coli (APEC). A total of 480 1-day-old Cherry Valley male ducks were randomly assigned to 8 treatments with 10 replicates, each replicate containing 10 ducks. A 4 × 2 factor design was used with four dietary zinc levels (0, 30, 60, 120 mg Zn/kg in the form Zn-Met was added to the corn-soybean basal diet) and challenged with or without APEC at 8-days-old ducks. The trial lasted for 14 days. The results showed that a dietary Zn-Met supplementation significantly increased body weight (BW) of 14 days and BW gain, and decreased mortality during 7-14-days-old ducks (p < 0.05). Furthermore, dietary 30, 60, 120 mg/kg Zn-Met supplementation noticeably increased the thymus index at 2 days post-infection (2 DPI) and 8 DPI (p < 0.05), and 120 mg/kg Zn-Met enhanced the serum IgA at 2 DPI and IgA, IgG, IgM, C3 at 8 DPI (p < 0.05). In addition, dietary 120 mg/kg Zn-Met supplementation dramatically increased villus height and villus height/crypt depth (V/C) of jejunum at 2 DPI and 8 DPI (p < 0.05). The TNF-α and IFN-γ mRNA expression were downregulated after supplemented with 120 mg/kg Zn-Met in jejunum at 8 DPI (p < 0.05). Moreover, dietary 120 mg/kg Zn-Met supplementation stimulated ZO-3, OCLN mRNA expression at 2 DPI and ZO-2 mRNA expression in jejunum at 8 DPI (p < 0.05), and improved the MUC2 concentration in jejunum at 2 DPI and 8 DPI (p < 0.05). At the same time, the cecal Bifidobacterium and Lactobacillus counts were increased (p < 0.05), and Escherichia coli counts were decreased (p < 0.05) after supplemented with Zn-Met. In conclusion, inclusion of 120 mg/kg Zn-Met minimizes the adverse effects of APEC challenge on meat ducks by improving growth performance and enhancing immune function and intestinal health.

Curcumin alleviated lipopolysaccharide-induced lung injury via regulating the Nrf2-ARE and NF-κB signaling pathways in ducks.

BACKGROUND: Under the intensive modern poultry farming system, the lung of duck is one of the main target organs for various bacterial and viral infections. Curcumin is a kind of natural polyphenol compound for which various beneficial biological functions exist, including being an anti-inflammatory, antioxidant, and antiviral. The aim of this work was to investigate the mechanism of curcumin-alleviated lipopolysaccharide (LPS)-induced lung damage by the nuclear erythroid 2-related factor 2 (Nrf2)-antioxidant reaction element (ARE) and nuclear factor kappa B (NF-κB) signaling pathway in ducks. RESULTS: In total, 450 one-day-old male specific pathogen-free ducks were randomly assigned into three dietary treatments: CON, basal diet; LPS, basal diet + LPS treatment; LPS + CUR, basal diet + LPS + 500 mg kg-1 of curcumin. At the end of the experiment (21 days), ducks in LPS treatment were challenged with 5 mg LPS per kilogram of body weight and the other two treatments were injected with the same dose of phosphate-buffered saline solution. The results showed that LPS caused acute inflammation, oxidation stress, and lung injury. Dietary addition of curcumin significantly relieved the oxidation stress and inflammation parameters. Moreover, the results showed that remission may be through the signaling pathways of both Nrf2-ARE and NF-κB. CONCLUSION: In conclusion, dietary supplementation of 500 mg kg-1 of curcumin exhibited a lung-protective effect in ducks. This experiment broadens the mode of metabolism actions of curcumin in the target organs and provides an insight for the application of curcumin in waterfowl feed. © 2022 Society of Chemical Industry.

Dietary Resistant Starch From Potato Regulates Bone Mass by Modulating Gut Microbiota and Concomitant Short-Chain Fatty Acids Production in Meat Ducks.

Gut microbiota interfered with using prebiotics may improve bone mass and alleviate the onset of bone problems. This study aimed to investigate the beneficial effect of resistant starch from raw potato starch (RPS) on bone health in meat ducks. Response to the dietary graded level of RPS supplementation, both tibia strength and ash were taken out linear and quadratic increase and positively correlated with increased propionate and butyrate levels in cecal content. Moreover, further outcomes of gut microbiota and micro-CT analysis showed the beneficial effect of RPS on bone mass might be associated with higher Firmicutes proportion and the production of short-chain fatty acids (SCFAs) in the cecum. Consistent with improving bone mass, SCFAs promoted phosphorus absorption, decreased the digestive tract pH, and enhanced intestinal integrity, which decreased the expression of pro-inflammatory genes in both gut and bone marrow, and consequently depressed osteoclastic bone resorption mediated by inflammatory cytokines. These findings highlight the importance of the "gut-bone" axis and provide new insight into the effect of prebiotics on bone health.

Dietary Supplementation With Didancao (Elephantopus scaber L.) Improves Meat Quality and Intestinal Development in Jiaji Ducks.

Didancao (Elephantopus scaber L.) has been used as a traditional herbal medicine and has exhibited a beneficial role in animal health. This study aimed to investigate the effects of dietary supplementation with E. scaber on growth performance, meat quality, intestinal morphology, and microbiota composition in ducks. A total of 480 Jiaji ducks (42 days old, male:female ratio = 1:1) were randomly assigned to one of four treatments. There were six replicates per treatment, with 20 ducks per replicate. The ducks in the control group (Con) were fed a basal diet; the three experimental groups were fed a basal diet supplementation with 30 (T1), 80 (T2), and 130 mg/kg (T3) of E. scaber. After a 48-day period of supplementation, growth performance, meat quality, intestinal morphology, and microbiota composition were evaluated. The results showed that no differences were observed in the final body weight, average daily feed intake, and average daily gain among the four groups. Compared with that in the Con group, the feed conversion in the T1 and T2 groups was increased significantly; the T2 group was shown to decrease the concentration of alanine aminotransferase in serum; the T3 group was lower than the Con group in the concentration of aspartate aminotransferase and was higher than the Con group in the concentration of high-density lipoprotein-cholesterol. The highest concentration of creatinine was observed in the T1 group. The T2 group was higher than the Con group in the contents of Phe, Ala, Gly, Glu, Arg, Lys, Tyr, Leu, Ser, Thr, Asp, and total amino acids in the breast muscle. Moreover, the T2 group was higher than the Con group in the contents of meat C18:2n-6 and polyunsaturated fatty acid. The concentration of inosinic acid in the T1, T2, and T3 groups was significantly higher than that in the Con group. However, the Con group was higher than the T2 or T3 group in the Zn content. The T2 group was lower than the Con group in the jejunal crypt depth. The T3 group was higher than the Con group in the ileal villus height and the ratio of villus height to crypt depth. In addition, the T3 group had a trend to significantly increase the abundance of Fusobacteria. Compared with the Con group, the T1 and T2 groups displayed a higher abundance of Subdoligranulum. Collectively, dietary supplementation with 80 mg/kg of E. scaber improves meat quality and intestinal development in ducks.

Using Extract From the Stems and Leaves of Yizhi (Alpiniae oxyphyllae) as Feed Additive Increases Meat Quality and Intestinal Health in Ducks.

Yizhi (Alpiniae Oxyphyllae, A. oxyphylla) has been widely used as an important traditional Chinese medicinal herb for centuries. Existing studies have shown that A. oxyphylla has numerous benefits in human and animal health. We hypothesized that extract from the stems and leaves of A. oxyphylla (AOE) as a feed additive may have positive effects on animal health and products. Thus, this study was conducted to evaluate the effects of AOE as a feed additive on growth performance, serum biochemical parameters, intestinal morphology, microbial composition, and meat quality in Jiaji ducks. A total of 240 Jiaji ducks of 42 days old (1675.8 ± 44.2 g, male: female ratio = 1:1) were blocked based on body weight and randomly allocated into four dietary treatments with three replicates that each had 20 duck individuals. The dietary treatments included: basal diet, control group (CK); basal diet supplementation with 30 mg/kg (Y1), 80 mg/kg (Y2), and 130 mg/kg (Y3) AOE, respectively, and lasted for 49 days. The results showed that average daily feed intake from day 42 to day 60 was decreased with the increasing level of AOE (P < 0.05). Compared with the CK group, the groups with AOE supplementation decreased serum LDL-C level (P < 0.05), the addition of 30 mg/kg AOE increased total amino acids, essential amino acids, branched-chain amino acids, nonessential amino acids, and umami taste amino acids (P < 0.05), but decreased selenium and zinc concentrations in breast muscle (P < 0.05). In addition, the supplementation of 30 or 130 mg/kg AOE significantly increased jejunal villus height (P < 0.05) and tended to increase the ratio of villus height to crypt depth in the jejunum (P = 0.092) compared to the CK group. Moreover, the addition of 30 mg/kg AOE showed a higher abundance of genus unclassified Bacteroidales and genus unclassified Ruminococcaceae than the CK group (P < 0.05). Therefore, dietary supplementation with 30 mg/kg AOE increased meat nutrition profile and flavor through promoting amino acid contents in breast muscle, as well as maintained intestine integrity and modulated the microbial composition. In conclusion, AOE as an antibiotic alternative displayed potential in maintaining intestinal health and improving meat quality.

Effects of Selenium-Enriched Yeast on Performance, Egg Quality, Antioxidant Balance, and Egg Selenium Content in Laying Ducks.

This study investigated the effects of dietary selenium-enriched yeast (Se yeast) supplementation on the laying performance, egg quality, plasma antioxidant balance, and egg selenium (Se) content in laying Longyan ducks. A total of 480 32-week-old ducks were randomly divided into four dietary treatments, each consisting of six replicates of 20 ducks. The dietary treatments were a control basal diet and basal diets with supplementation of 0.05, 0.15, and 0.25 mg Se/kg via Se yeast. The analyzed Se contents of the four diets were 0.15, 0.21, 0.36, and 0.43 mg Se/kg, respectively. Dietary Se yeast supplementation had no apparent effects on laying performance and egg quality (p > 0.05), but it improved the antioxidant balance of ducks, as inferred by greater glutathione peroxidase and catalase activities, and decreased the malondialdehyde content in plasma of ducks (p < 0.05). It was suggested that the Se content in the basal diet containing 0.15 mg/kg of Se requirement is adequate for productive performance, but not for the antioxidant balance of laying ducks. Besides that, the Se contents in the yolk, albumen, and whole egg increased linearly as the Se supplementation levels increased. With more feeding days, the Se contents in the yolk and whole egg from non-Se-yeast-supplemented ducks increased linearly (p < 0.05), while those from Se-yeast-supplemented ducks showed a quadratic relationship (p < 0.05). In conclusion, the Se content of the basal diet at 0.15 mg/kg was adequate for laying performance and egg quality traits in laying ducks. Dietary Se yeast supplementation is beneficial to improve the antioxidant balance of laying ducks and increase the Se deposition in eggs for producing Se-enriched eggs. Based on the quadratic model or the quadratic broken-line model analyses, supplemental 0.19 mg Se/kg via Se yeast, with a total equivalent of 0.34 mg Se/kg in the diet, could provide the optimum antioxidant balance in laying ducks. Dietary supplementation of 0.25 mg Se/kg via Se yeast, with a total equivalent of 0.40 mg Se/kg in the diet, could lead to achieving the desired Se content in the whole egg.

Effects of graded levels of phytase supplementation on growth performance, serum biochemistry, tibia mineralization, and nutrient utilization in Pekin ducks.

A total of 560 one-day-old Pekin ducks were randomly allocated to 7 treatments with 8 replicate cages of 10 ducks per cage. The treatments included a corn-rice bran-soybean meal-based diet with recommended nonphytate phosphorus (NPP) (0.40% for 1-14 D/0.35% for 15-35 D, positive control; PC), NPP-deficient diet (0.22% for 1-14 D/0.18% for 15-35 D, negative control; NC), and NC diets supplemented with different levels of phytase (500, 2,500, 5,000, 7,500, 10,000 FTU/kg). Compared with the PC diet, feeding the NC diet significantly decreased (P < 0.05) the bird growth performance, serum total protein, and albumin concentration as well as tibia bone mineralization and strength and increased (P < 0.05) serum calcium (Ca), urea content, and alkaline phosphatase activity throughout the experimental period. Phytase supplementation to NC diets at 5,000 to 10,000 FTU/kg restored (P < 0.05) growth performance, serum biochemical parameters, and tibia traits when compared with the levels of the PC. Moreover, the addition of phytase linearly increased (P < 0.05) dietary protein, Ca, and phosphorus (P) utilization as well as nitrogen output, and excreta iron, copper, manganese, and zinc concentration quadratically increased (P < 0.05) as well as P output. In conclusion, phytase at ≥5,000 FTU/kg was effective in ameliorating the negative effects of NC diets and reducing trace mineral supplementation in diet of Pekin ducks.

Effects of Achyranthes bidentata polysaccharides on performance, immunity, antioxidant capacity, and meat quality in Pekin ducks.

This study was conducted to evaluate the effects of Achyranthes bidentata polysaccharide (ABP) on growth performance, antioxidant capacity, immune function, relative organ weight, ileal microflora, and meat quality in Pekin ducks. A total of 1,200 female 1-day-old Pekin ducklings (51.2 ± 0.2 g) were blocked based on body weight (BW) and randomly allocated into 3 treatments with 10 replicates of 40 birds each. The experiment lasted for 6 wk, and dietary treatments included corn-soybean meal-based diet supplemented with 0, 0.02, and 0.04% ABP. The supplementation of ABP increased (P < 0.05) body weight gain (BWG) and final BW linearly during day 22 to 42 and day 1 to 42, respectively, but decreased (P < 0.05) feed-to-gain ratio (F/G) linearly during day 22 to 42 and day 1 to 42. The inclusion of ABP increased (P < 0.05) serum superoxide dismutase, glutathione peroxidase, total antioxidative capacity, catalase, complement3, complement4, immunoglobin A, immunoglobin G, interleukin-2, interferon-γ, and tumor necrosis factor-α linearly. The relative weight of breast meat was increased (P < 0.05) linearly, but the relative weight of abdominal fat was decreased (P < 0.05) linearly with the increasing dietary ABP supplementation. The supplementation of ABP increased (P < 0.05) ileal Lactobacilli counts linearly, whereas decreased (P < 0.05) Escherichia coli counts linearly. Taken together, the inclusion of ABP promoted BWG and final BW during day 22 to 42 and the entire experiment, decreased F/G during day 22 to 42 and day 1 to 42, and partially improved antioxidant activities, immunity, and gut microflora in Pekin ducks.

Effects of dietary lipid sources on growth performance and carcass traits in Pekin ducks.

This study was conducted to determine the influence of dietary lipid sources on growth performance, carcass traits and taste scores in Pekin ducks. A total of 1,500 fifteen-day-old ducks (820 ± 22 g) were blocked based on body weight (BW), and randomly allotted to 3 treatments with 10 replicates of 50 birds each (25 males and 25 females). The experiment lasted for 4 wk, and dietary treatments included 3 different lipid sources (soybean oil, duck fat, and palm oil), which were evaluated in corn-soybean meal diets (3250 kcal/kg metabolizable energy and 16.5% crude protein for grower diet and 3350 kcal/kg metabolizable energy and 15.5% crude protein for finisher diet). During days 15 to 28, feeding soybean oil and palm oil diets increased (P < 0.05) body weight gain (BWG), but decreased (P < 0.05) feed intake, feed-to-gain ratio (F/G) and caloric conversion compared with duck fat. During days 29 to 42, birds fed duck fat diet had higher BWG, but lower (P < 0.05) F/G and caloric conversion than those fed soybean oil and palm oil diets. Overall, feeding soybean oil diet increased (P < 0.05) BWG and final BW, but decreased (P < 0.05) F/G compared with palm oil. Birds fed duck fat diet had higher (P < 0.05) skin, subcutaneous fat and abdominal fat yield compared with palm oil. Left breast meat yield in soybean oil group was higher (P < 0.05) than that in duck fat and palm oil groups. Birds in soybean oil group had lower (P < 0.05) roasting loss, but higher (P < 0.05) comprehensive score compared with duck fat and palm oil. In summary, birds fed soybean oil diet had the best growth performance and taste scores for roasting, whereas the duck fat was better in abdominal fat and subcutaneous fat yield than soybean oil and palm oil in Pekin ducks from 15 to 42 d of age under the same nutritional level.