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-1β,IL-6 and TNF-αwere 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-αexpression levels and TNF-αprotein 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.

The Effect of Tryptophan on Serotonin-Like Neurons in Duck Cerebellum

Healthy Cherry Valley ducks were used in the present study. Different doses of tryptophan were injected intraperitoneally to them after being fasted 4 h （8：00 a.m.-12：00 a.m.）. One hour later, they were deeply anaesthetized and perfused. The cerebellum was removed to make serial paraffin longitudinal sections. The streptavidin-biotin-peroxidase complex （SABC） method was used to study the distribution of serotonin-like neurons in the cerebellum. All films were analysed by using a computer-assisted image analysis system. Serotonin-like neurons are only localized in cerebellar Purkinje cell layer. The optical density averages of serotonin-like neurons in 200 and 100 mg kg^-1 group are significantly higher than that of 0 mg kg^-1 group （P〈0.01）. These results show that serotonin-like neurons are distributed in Purkinje cell layer and that excessive tryptophan can affect the content of serotonin in cerebellum.

Effects of Calcium Lignosulfonate(CaLS)on Growth Performance,Slaughter Performance and Antioxidant Function of Meat Duck

[Objective]The paper was to study the effects of calcium lignosulfonate(CaLS)on feed processing performance,growth performance,slaughter performance and antioxidant function of cherry valley duck.[Method]A total of 48010-day-old cherry valley ducks were selected and randomly divided into four treatments,10 replicates each treatment and 12 meat ducks each replicate(half male and half female).The ducks in control group were fed with basal diet,and those in experimental groups were fed with the basal diet adding 0.2%,0.4%and 0.6%CaLS,respetively.The trial lasted 28 d.[Result](1)CaLS significantly reduced feed pulverization rate of meat duck(F<0.05),and significantly increased PDI and starch gelatinization degree(F<0.05);adding CaLS had no significant impact on the processing cost(F>0.05),but the granulation electric charge per ton feed could be reduced by 1.06 yuan.(2)CaLS had no significant effect on growth performance,slaughter performance and organ index of meat duck(Q0.05).(3)Compared with the control group,there were no significant differences in serum GSH-Px,T-SOD,T-AOC activities and MDA content of three CaLS groups(F>0.05).[Conclusion]CaLS could improve the processing quality of meat duck feed and reduce the processing cost,hut could not improve the growth performance,slaughter performance and antioxidant function of meat duck.

Dietary supplementation of ferrous glycinate improves intestinal barrier function by modulating microbiota composition in Cherry Valley ducks

Ferrous glycinate(Fe-Gly)has been increasingly used as iron fortification in the diets of weaned piglets and broilers,but the effect of Fe-Gly on intestinal barrier function in meat ducks has not been well defined.This study therefore investigated the effect of Fe-Gly on apparent nutrient utilization,hematological indices,intestinal morphological parameters,intestinal barrier function and microbial composition in meat ducks.A total of 672 one-day-old Cherry Valley ducks were randomly divided into 6treatments(8 replicates for each treatment and 14 ducks for each replicate)and fed diets with 0(control),30,60,90 and 120 mg/kg Fe-Gly or 120 mg/kg Fe SO4for 35 d.The results showed that diets supplemented with Fe-Gly significantly increased average daily gain(ADG),average daily feed intake(ADFI),hematocrit(HCT),mean cell volume(MCV),the apparent utilization of dry matter(DM)and metabolizable energy(ME),villus height(VH)and villus height-to-crypt depth ratio(V:C)(P<0.05).FeGly also significantly up-regulated barrier-related genes including zonula occludens-1(ZO-1),zonula occludens-2(ZO-2),mucin 2(MUC2)and lysozyme(LYZ)(P<0.05),and down-regulated the m RNA expression of claudin-2(CLDN2)and occludin(OCLN)in the jejunum(P<0.05).The 16S r RNA sequence analysis indicated that the diet with Fe-Gly had a higher relative abundance of Intestinimonas and Romboutsia(P<0.05),which have an ability to produce short chain fatty acids(SCFAs),especially butyric acid.It also decreased the relative abundance of pathobiont,including Megamonas,Eubacterium_coprostanoligenes_group and Plebeius(P<0.05).Additionally,diets supplemented with 120 mg/kg Fe-Gly significantly increased the apparent utilization of DM and ME(P<0.05)and decreased the relative abundance of Megamonas_unclassified and Bacteroides_unclassified compared with those fed120 mg/kg Fe SO4(P<0.05).These results revealed that diets supplemented with Fe-Gly exerted a potent beneficial effect on physical,chemical,immune and microbial barriers,thereby improving the integrity of the intestinal structure,promoting the digestion and absorption of nutrients to a certain extent,and ultimately elevating the growth performance of ducks.

Effects of aflatoxins on growth performance and skeletal muscle of Cherry Valley meat male ducks

This study aims to evaluate the effects of aflatoxins on growth performance and skeletal muscle of Cherry Valley meat male ducks as they grow and develop. One-day-old healthy meat male ducks(n = 180) were randomly divided into 2 groups; there were 6 replicates in each group and 15 ducks in each replicate. The control group was fed a basic diet, and the experimental group was fed a mold-exposed cottonseed meal diet containing aflatoxins instead of normal cottonseed meal. The experimental period was 35 days, and divided into two stages of 1 to 14 days(early stage) and 15 to 35 days(late stage). During the experimental period, live weight, breast muscle weight and thigh muscle weight of meat male ducks were measured weekly. Results showed as follows: 1) aflatoxins contained in the mold-exposed diet significantly reduced daily weight gain and feed intake, and increased feed-to-gain ratio of meat male ducks at different ages(P < 0.05); 2) the Gompertz equation(W_t = W_m exp {-exp [-B(t-t~*)]}) could successfully fit the growth curve and growth and developmental patterns of skeletal muscles of Cherry Valley meat male ducks(R^2≥0.97); 3) the relationship between chest muscle and live weight was the best described by a power regression and polynomial regression(R^2 = 0.99); the relationship between live weight and thigh muscle weight was the best described by linear regression, polynomial regression, and power regression(R^2 = 0.99); 4) aflatoxins in the mold-exposed diet significantly reduced live weight, breast muscle weight and thigh muscle weight of Cherry Valley meat male ducks at various ages; and 5) aflatoxins delayed the age at peak in growth of meat male ducks, and reduced weights at the peak for breast muscle, thigh muscle and whole body as well as the maximal daily weight gain. In summary,aflatoxins delayed growth of Cherry Valley meat male ducks and development of skeletal muscle.