Responses of growth performance,antioxidant function,small intestinal morphology and mRNA expression of jejunal tight junction protein to dietary iron in yellow-feathered broilers

This study aimed to investigate the dose-effect of iron on growth performance,antioxidant function.intestinal morphology,and mRNA expression of jejunal tight junction protein in 1-to21-d-old yellow-feathered broilers.A total of 7201-d-old yellow-feathered maleb roilers were allocated to 9 treatments with 8 replicate cages of 10 birds per cage.The dietary treatments were consisted of a basal diet(contained 79.6 mg Fe kg^(-1))supplemented with 0,20,40,60,80,160,320,640,and 1,280 mg Fe kg^(-1)in the form of FeSO_(4)·7H_(2)O.Compared with the birds in the control group,birds supplemented with 20mg Fe kg^(-1)had higher average daily gain(ADG)(P<0.0001).Adding 640 and 1,280 mg Fe kg^(-1)significantly decreased ADG(P<0.0001)and average daily feed intake(ADFI)(P<0.0001)compared with supplementation of 20mg Fe kg^(-1).Malondialdehyde(MDA)concentration in plasma and duodenum increased linearly(P<0.0001),but MDA concentration in liver and jejunum increased linearly(P<0.05)or quadratically(P<0.05)with increased dietary Fe concentration.The villus height(VH)in duodenum and jejunum,and the ratio of villus height to crypt depth(V/C)in duodenum decreased linearly(P?0.05)as dietary Feincreased.As dietary Fe increased,the jejunal relative mRNA abundance of claudin-1 decreased linearly(P=0.001),but the jejunal relative mRNA abundance of zona occludens-1(ZO-1)and occludin decreased linearly(P?0.05)or quadratically(P?0.05).Compared with the supplementation of 20 mg Fe kg^(-1),the supplementation of640 mg Fe kg^(-1)or higher increased(P?0.05)MDA concentrations in plasma,duodenum,and jejunum,decreased VH in the duodenum and jejunum,and the addition of 1,280 mg Fe kg^(-1)reduced(P?0.05)the jejunal tight junction protein(claudin-1,ZO-1,occludin)mRNA abundance.In summary,640 mg of supplemental Fe kg^(-1)or greater was associated with decreased growth performance,increased oxidative stress,disrupted intestinal morphology,and reduced mRNA expression of jejunal tight junction protein.

Correlation between Intestinal Health and Coccidiosis Prevalence in Broilers during Different Seasons of the Year in Brazil from 2012 to 2018

Coccidiosis is a disease caused by intracellular protozoan parasites, specifically belonging to the genus Eimeria. These parasites target the gastrointestinal tract in different types of hosts, causing sores in the intestinal lining. The presence of these lesions reduces the animal’s ability to digest and absorb nutrients, significantly impacting their overall performance. The current study aimed to explore the potential correlation between seasonal variations and the incidence of Eimeria spp-induced lesions in broiler chickens’ gastrointestinal tracts in Brazil from 2012 to 2018. A total of 8,607 broiler chickens, aged 14 to 42 days, were sampled from 103 poultry integrated companies in Brazil to conduct intestinal health examinations. The sampling process involved selecting 3 to 6 chickens from each poultry house for examination. The assessment included various abnormalities such as shedding of intestinal cells and excessive fluid and mucus presence, thickening and tension of the intestines, food movement, roughened mucosal surface resembling a Turkish towel in the small intestine, tissue death, duodenal inflammation, intestinal inflammation, gizzard erosion, presence of worms and bedding material, and ingestion of mealworms. During the seasons, winter exhibited the highest average occurrence of Eimeria maxima microorganisms at 52.83%, with E. acervulina following closely at 26.42% in second place. In spring, E. maxima had an occurrence of 11.31%, while in fall, E. tenella had the lowest occurrence at 6.74%. When analyzing the seasonal occurrence of Eimeria, it was observed that E. maxima micro was more common during winter compared to summer (P = 0.0491). However, no discernible variation was observed in the occurrence of the remaining species across different seasons. Research findings suggest that subclinical coccidiosis is most prevalent during the winter season in Brazil. Likewise, clinical disease caused by E. acervulina is also prevalent during this time. In contrast, E. maxima is more likely to cause clinical disease in the spring, whereas E. tenella is more commonly associated with clinical disease in the fall. Lesions induced by Eimeria spp. are associated with factors influencing the overall health of broiler intestines. These findings allow for the utilization of seasonal metrics in disease management, thereby reducing economic losses associated with the condition.

Hypoxia-mediated programmed cell death is involved in the formation of wooden breast in broilers

Background Wooden breast(WB)myopathy is a common myopathy found in commercial broiler chickens worldwide.Histological examination has revealed that WB myopathy is accompanied by damage to the pectoralis major(PM)muscle.However,the underlying mechanisms responsible for the formation of WB in broilers have not been fully elucidated.This study aimed to investigate the potential role of hypoxia-mediated programmed cell death(PCD)in the formation of WB myopathy.Results Histological examination and biochemical analysis were performed on the PM muscle of the control(CON)and WB groups.A significantly increased thickness of the breast muscle in the top,middle,and bottom portions(P<0.01)was found along with pathological structure damage of myofibers in the WB group.The number of capillaries per fiber in PM muscle,and the levels of p O_(2) and s O_(2) in the blood,were significantly decreased(P<0.01),while the levels of p CO_(2) and TCO_(2) in the blood were significantly increased(P<0.05),suggesting hypoxic conditions in the PM muscle of the WB group.We further evaluated the PCD-related pathways including autophagy,apoptosis,and necroptosis to understand the consequence response to enhanced hypoxic conditions in the PM muscle of birds with WB.The ratio of LC3 II to LC3 I,and the autophagy-related factors HIF-1α,BNIP3,Beclin1,AMPKα,and ULK1 at the m RNA and protein levels,were all significantly upregulated(P<0.05),showing that autophagy occurred in the PM muscle of the WB group.The apoptotic index,as well as the expressions of Bax,Cytc,caspase 9,and caspase 3,were significantly increased(P<0.05),whereas Bcl-2 was significantly decreased(P<0.05)in the WB-affected PM muscle,indicating the occurrence of apoptosis mediated by the mitochondrial pathway.Additionally,the expressions of necroptosis-related factors RIP1,RIP3,and MLKL,as well as NF-κB and the pro-inflammatory cytokines TNF-α,IL-1β,and IL-6,were all significantly enhanced(P<0.05)in the WB-affected PM muscle.Conclusions The WB myopathy reduces blood supply and induces hypoxia in the PM muscle,which is closely related to the occurrence of PCD including apoptosis,autophagy,and necroptosis within myofibers,and finally leads to abnormal muscle damage and the development of WB in broilers.

Effects of methionine supplementation in a reduced protein diet on growth performance, oxidative status, intestinal health, oocyst shedding, and methionine and folate metabolism in broilers under Eimeria challenge

Background This study investigated effects of different methionine(Met)supplementation levels in a reduced protein diet on growth performance,intestinal health,and different physiological parameters in broilers under Eimeria challenge.A total of 600 fourteen-day-old Cobb500 male broilers were challenged with E.maxima,E.tenella,and E.acervulina,and randomly allocated in a 2×5 factorial arrangement.Birds received normal protein diets(20%crude protein,NCP)or reduced protein diets(17%crude protein,LCP),containing 2.8,4.4,6.0,7.6,and 9.2 g/kg of Met.Results On 6 and 9 days post inoculation(DPI),increasing Met level linearly improved the growth performance(P<0.05).Total oocyst shedding linearly increased as Met level increased(P<0.05).Duodenal villus height(VH):crypt depth(CD)in the LCP groups were higher on 6 DPI(P<0.01)while lower on 9 DPI(P<0.05)compared to the NCP groups.Jejunal CD and duodenal VH:CD changed quadratically as Met level increased(P<0.05).On 6 DPI,liver glutathione(GSH)and glutathione disulfide(GSSG)linearly increased as Met level increased(P<0.05).On 9 DPI,GSSG quadratically increased,whereas GSH:GSSG quadratically decreased as Met levels increased(P<0.05).The expression of amino acid transporters linearly decreased as Met level increased(P<0.05).The expression of zonula occludens 2 and claudin-1 linearly increased on 6 DPI whereas decreased on 9 DPI as Met level increased(P<0.05).The expressions of cytokines were lower in the LCP groups than the NCP groups(P<0.05).Interaction effects were found for the expression of IL-10 and TNFαon 6 DPI(P<0.05),where it only changed quadratically in the NCP group as Met level increased.The expression of Met and folate metabolism genes were lower in the LCP groups than the NCP groups on 9 DPI(P<0.05).The expression of these genes linearly or quadratically decreased as Met level increased(P<0.05).Conclusion These results revealed the regulatory roles of Met in different physiological parameters including oxidative status,intestinal health,and nutrient metabolism in birds fed reduced protein diet and challenged with Eimeria.

Dietary manganese supplementation inhibits abdominal fat deposition possibly by regulating gene expression and enzyme activity involved in lipid metabolism in the abdominal fat of broilers

Excessive abdominal fat deposition seriously restricts the production efficiency of broilers.Several studies found that dietary supplemental manganese(Mn)could effectively reduce the abdominal fat deposition of broilers,but the underlying mechanisms remain unclear.The present study aimed to investigate the effect of dietary supplementation with the inorganic or organic Mn on abdominal fat deposition,and enzyme activity and gene expression involved in lipid metabolism in the abdominal fat of male or female broilers.A total of 4201-d-old AA broilers(half males and half females)were randomly allotted by body weight and gender to 1 of 6 treatments with 10 replicates cages of 7 chicks per cage in a completely randomized design involving a 3(dietary Mn addition)×2(gender)factorial arrangement.Male or female broilers were fed with the Mn-unsupplemented basal diets containing 17.52 mg Mn kg^(-1)(d 1-21)and 15.62 mg Mn kg^(-1)(d 22-42)by analysis or the basal diets supplemented with 110 mg Mn kg^(-1)(d 1-21)and 80 mg Mn kg^(-1)(d 22-42)as either the Mn sulfate or the Mn proteinate with moderate chelation strength(Mn-Prot M)for 42 d.The results showed that the interaction between dietary Mn addition and gender had no impact(P>0.05)on any of the measured parameters;abdominal fat percentage of broilers was decreased(P<0.003)by Mn addition;Mn addition increased(P<0.004)adipose triglyceride lipase(ATGL)activity,while Mn-Prot M decreased(P<0.002)the fatty acid synthase(FAS)activity in the abdominal fat of broilers compared to the control;Mn addition decreased(P<0.009)diacylglycerol acyltransferase 2(DGAT2)mRNA expression level and peroxisome proliferator-activated receptor γ(PPARγ)mRNA and protein expression levels,but up-regulated(P<0.05)the ATGL mRNA and protein expression levels in the abdominal fat of broilers.It was concluded that dietary supplementation with Mn inhibited the abdominal fat deposition of broilers possibly via decreasing the expression of PPARγand DGAT2 as well as increasing the expression and activity of ATGL in the abdominal fat of broilers,and Mn-Prot M was more effective in inhibiting the FAS acitivity.

Transcriptomic and epigenomic landscapes of muscle growth during the postnatal period of broilers

Background Broilers stand out as one of the fastest-growing livestock globally,making a substantial contribution to animal meat production.However,the molecular and epigenetic mechanisms underlying the rapid growth and development of broiler chickens are still unclear.This study aims to explore muscle development patterns and regulatory networks during the postnatal rapid growth phase of fast-growing broilers.We measured the growth performance of Cornish(CC)and White Plymouth Rock(RR)over a 42-d period.Pectoral muscle samples from both CC and RR were randomly collected at day 21 after hatching(D21)and D42 for RNA-seq and ATAC-seq library construction.Results The consistent increase in body weight and pectoral muscle weight across both breeds was observed as they matured,with CC outpacing RR in terms of weight at each stage of development.Differential expression analysis identified 398 and 1,129 genes in the two dimensions of breeds and ages,respectively.A total of 75,149 ATAC-seq peaks were annotated in promoter,exon,intron and intergenic regions,with a higher number of peaks in the promoter and intronic regions.The age-biased genes and breed-biased genes of RNA-seq were combined with the ATAC-seq data for subsequent analysis.The results spotlighted the upregulation of ACTC1 and FDPS at D21,which were primarily associated with muscle structure development by gene cluster enrichment.Additionally,a noteworthy upregulation of MUSTN1,FOS and TGFB3 was spotted in broiler chickens at D42,which were involved in cell differentiation and muscle regeneration after injury,suggesting a regulatory role of muscle growth and repair.Conclusions This work provided a regulatory network of postnatal broiler chickens and revealed ACTC1 and MUSTN1 as the key responsible for muscle development and regeneration.Our findings highlight that rapid growth in broiler chickens triggers ongoing muscle damage and subsequent regeneration.These findings provide a foundation for future research to investigate the functional aspects of muscle development.

Gut microbiota intervention attenuates thermogenesis in broilers exposed to high temperature through modulation of the hypothalamic 5‑HT pathway

Background Broilers have a robust metabolism and high body temperature,which make them less tolerant to hightemperature(HT)environments and more susceptible to challenges from elevated temperatures.Gut microbes,functioning as symbionts within the host,possess the capacity to significantly regulate the physiological functions and environmental adaptability of the host.This study aims to investigate the effects of gut microbial intervention on the body temperature and thermogenesis of broilers at different ambient temperatures,as well as the underlying mechanism involving the"gut-brain"axis.Methods Broilers were subjected to gut microbiota interference with or without antibiotics(control or ABX)starting at 1 day of age.At 21 day of age,they were divided into 4 groups and exposed to different environments for 7 d:The control and ABX groups at room temperature(RT,24±1℃,60%relative humidity(RH),24 h/d)and the control-HT and ABX-HT groups at high temperature(HT,32±1℃,60%RH,24 h/d).Results The results demonstrated that the antibiotic-induced gut microbiota intervention increased body weight and improved feed conversion in broiler chickens(P<0.05).Under HT conditions,the microbiota intervention reduced the rectal temperature of broiler chickens(P<0.05),inhibited the expression of avUCP and thermogenesisrelated genes in breast muscle and liver(P<0.05),and thus decreased thermogenesis capacity.Furthermore,the gut microbiota intervention blunted the hypothalamic‒pituitary‒adrenal axis and hypothalamic–pituitary–thyroid axis activation induced by HT conditions.By analyzing the cecal microbiota composition of control and ABX chickens maintained under HT conditions,we found that Alistipes was enriched in control chickens.In contrast,antibioticinduced gut microbiota intervention resulted in a decrease in the relative abundance of Alistipes(P<0.05).Moreover,this difference was accompanied by increased hypothalamic 5-hydroxytryptamine(5-HT)content and TPH2 expression(P<0.05).Conclusions These findings underscore the critical role of the gut microbiota in regulating broiler thermogenesis via the gut-brain axis and suggest that the hypothalamic 5-HT pathway may be a potential mechanism by which the gut microbiota affects thermoregulation in broilers.

The chemical characteristics of different sodium iron ethylenediaminetetraacetate sources and their relative bioavailabilities for broilers fed with a conventional corn‑soybean meal diet

Background Our previous studies demonstrated that divalent organic iron(Fe)proteinate sources with higher complexation or chelation strengths as expressed by the greater quotient of formation(Qf)values displayed higher Fe bioavailabilities for broilers.Sodium iron ethylenediaminetetraacetate(NaFeEDTA)is a trivalent organic Fe source with the strongest chelating ligand EDTA.However,the bioavailability of Fe when administered as NaFeEDTA in broilers and other agricultural animals remains untested.Herein,the chemical characteristics of 12 NaFeEDTA products were determined.Of these,one feed grade NaFeEDTA(Qf=2.07×10^(8)),one food grade NaFeEDTA(Qf=3.31×10^(8)),and one Fe proteinate with an extremely strong chelation strength(Fe-Prot ES,Qf value=8,590)were selected.Their bioavailabilities relative to Fe sulfate(FeSO_(4)·7H_(2)O)for broilers fed with a conventional corn-soybean meal diet were evaluated during d 1 to 21 by investigating the effects of the above Fe sources and added Fe levels on the growth performance,hematological indices,Fe contents,activities and gene expressions of Fe-containing enzymes in various tissues of broilers.Results NaFeEDTA sources varied greatly in their chemical characteristics.Plasma Fe concentration(PI),transferrin saturation(TS),liver Fe content,succinate dehydrogenase(SDH)activities in liver,heart,and kidney,catalase(CAT)activity in liver,and SDH mRNA expressions in liver and kidney increased linearly(P<0.05)with increasing levels of Fe supplementation.However,differences among Fe sources were detected(P<0.05)only for PI,liver Fe content,CAT activity in liver,SDH activities in heart and kidney,and SDH mRNA expressions in liver and kidney.Based on slope ratios from multiple linear regressions of the above indices on daily dietary analyzed Fe intake,the average bioavailabilities of Fe-Prot ES,feed grade NaFeEDTA,and food grade NaFeEDTA relative to the inorganic FeSO_(4)·7H_(2)O(100%)for broilers were 139%,155%,and 166%,respectively.Conclusions The bioavailabilities of organic Fe sources relative to FeSO_(4)·7H_(2)O were closely related to their Qf values,and NaFeEDTA sources with higher Qf values showed higher Fe bioavailabilities for broilers fed with a conventional corn-soybean meal diet.

Effects of Enteromorpha prolifera polysaccharides on growth performance,intestinal barrier function and cecal microbiota in yellow-feathered broilers under heat stress

Background Global warming leading to heat stress(HS)is becoming a major challenge for broiler production.This study aimed to explore the protective effects of seaweed(Enteromorpha prolifera)polysaccharides(EPS)on the intestinal barrier function,microbial ecology,and performance of broilers under HS.A total of 144 yellow-feathered broilers(male,56 days old)with 682.59±7.38 g were randomly assigned to 3 groups:1)TN(thermal neutral zone,23.6±1.8℃),2)HS(heat stress,33.2±1.5℃ for 10 h/d),and 3)HSE(HS+0.1%EPS).Each group contained 6 replicates with 8 broilers per replicate.The study was conducted for 4 weeks;feed intake and body weights were measured at the end of weeks 2 and 4.At the end of the feeding trial,small intestine samples were collected for histomorphology,antioxidant,secretory immunoglobulin A(s Ig A)content,apoptosis,gene and protein expression analysis;cecal contents were also collected for microbiota analysis based on 16S r DNA sequencing.Results Dietary EPS promoted the average daily gain(ADG)of broilers during 3–4 weeks of HS(P<0.05).At the end of HS on broilers,the activity of total superoxide dismutase(T-SOD),glutathione S-transferase(GST),and the content of s Ig A in jejunum were improved by EPS supplementation(P<0.05).Besides,dietary EPS reduced the epithelial cell apoptosis of jejunum and ileum in heat-stressed broilers(P<0.05).Addition of EPS in HS group broilers'diet upregulated the relative m RNA expression of Occludin,ZO-1,γ-GCLc and IL-10 of the jejunum(P<0.05),whereas downregulated the relative m RNA expression of NF-κB p65,TNF-αand IL-1βof the jejunum(P<0.05).Dietary EPS increased the protein expression of Occludin and ZO-1,whereas it reduced the protein expression of NF-κB p65 and MLCK(P<0.01)and tended to decrease the protein expression of TNF-α(P=0.094)in heat-stressed broilers.Furthermore,the proportions of Bacteroides and Oscillospira among the three groups were positively associated with jejunal apoptosis and pro-inflammatory cytokine expression(P<0.05)and negatively correlated with jejunal Occludin level(P<0.05).However,the proportions of Lactobacillus,Barnesiella,Subdoligranulum,Megasphaera,Collinsella,and Blautia among the three groups were positively related to ADG(P<0.05).Conclusions EPS can be used as a feed additive in yellow-feathered broilers.It effectively improves growth performance and alleviates HS-induced intestinal injury by relieving inflammatory damage and improving the tight junction proteins expression.These beneficial effects may be related to inhibiting NF-κB/MLCK signaling pathway activation and regulation of cecal microbiota.

Transcriptome analysis reveals steroid hormones biosynthesis pathway involved in abdominal fat deposition in broilers

Excessive abdominal fat deposition reduces the feed efficiency and increase the cost of production in broilers.Therefore,it is an important task for poultry breeders to breed broilers with low abdominal fat.Abdominal fat deposition is a highly complex biological process,and its molecular basis remains elusive.In this study,we performed transcriptome analysis to compare gene expression profiles at different stages of abdominal fat deposition to identify the key genes and pathways involved in abdominal fat accumulation.We found that abdominal fat weight(AFW)increased gradually from day 35(D35)to 91(D91),and then decreased at day 119(D119).Accordingly,after detecting differentially expressed genes(DEGs)by comparing gene expression profiles at D35 vs.D63 and D35 vs.D91,and identifying gene modules associated with fat deposition by weighted gene co-expression network analysis(WGCNA),we performed intersection analysis of the detected DEGs and WGCNA gene modules and identified 394 and 435 intersecting genes,respectively.The results of the Gene Ontology(GO)functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analyses showed that the steroid hormone biosynthesis and insulin signaling pathways were co-enriched in all intersecting genes,steroid hormones have been shown that regulated insulin signaling pathway,indicating the importance of the steroid hormone biosynthesis pathway in the development of broiler abdominal fat.We then identified 6 hub genes(ACTB,SOX9,RHOBTB2,PDLIM3,NEDD9,and DOCK4)related to abdominal fat deposition.Further analysis also revealed that there were direct interactions between 6 hub genes.SOX9 has been shown to bind to proteins required for steroid hormone receptor binding,and RHOBTB2 indirectly regulates the steroid hormones biosynthesis through cyclin factor,and ultimately affect fat deposition.Our results suggest that the genes RHOBTB2 and SOX9 play an important role in fat deposition in broilers,by regulating steroid hormone synthesis.These findings provide new targets and directions for further studies on the mechanisms of fat deposition in chicken.

Effects of Fresh Cupressus sempervirens Leaves Infusion on Growth Performance, Intestinal Microbiota and Haemato-Biochemical Parameters in Broilers

The accumulation of growth-promoting antibiotic residues in animal products and the resistance developed by bacteria in poultry farms has led to a search for natural compounds derived from plants. This study was designed to promote the production performance of broiler chickens using fresh Cupressus sempervirens leaves infusion. Fresh Cupressus sempervirens leaves were harvested, washed, chopped and ground to a paste using a blender and fermented for three days in a closed container at a rate of 500 g/L of water. The solution obtained was filtered and added at the rate of 2, 4, 6, 8 and 10 ml/L of drinking water. The chickens fed on the graded level of the solution were compared to a control ration without an additive and positive control group supplemented with 1 g antibiotic/kg feed. At the finisher phase and throughout the study period, water intake increased significantly (P < 0.05) with increasing levels of infusion. Feed intake decreased significantly (P < 0.05) with 2 and 4 ml of infusion/L drinking water. Live weight and weight gain were significantly (P < 0.05) higher with 6 ml/L, while feed conversion significantly (P < 0.05) decreased with the same treatment compared with the control treatment without additives (T0). Carcass characteristics were not significantly (P > 0.05) affected by the inclusion of Cupressus sempervirens infusion. Haematological parameters significantly (P < 0.05) increase independently of the rate of incorporation of the infusion into the drinking water, with the exception of RBCs, MCHT and PCT. Serum content in total protein, globulins, LDL cholesterol and triglycerides were significantly (P < 0.05) high with 8 and 10 ml Cupressus sempervirens infusion/litre drinking water as compared to all other treatments. AST, ALT, urea, creatine, albumin, total cholesterol and HDL-cholesterol were not significantly affected. The lactic acid bacteria load increased significantly (P E. coli and salmonella counts decreased significantly (P < 0.05) with infusion compared to the control without additive. In conclusion, 6 ml of Cupressus sempervirens infusion can be used as an alternative to antibiotic feed additives to promote growth performance in broilers.

Technical-Economic Performance, Carcass and Meat Quality of COBB500 Broilers Fed Rations Incorporating Mango By-Product Feeds in Ivory Coast (West Africa)

The study evaluated the growth performance and carcass quality of COBB500 broilers fed two experimental rations incorporating feed and mango fine ED10 for a batch of 83 birds, ED20 (batch of 83 birds) in comparison with a commercial control ration CCD (84 birds). For this purpose, 250 day-old chicks of this breed were purchased in Korhogo and transported to Tengréla in Ivory Coast for rearing. The results show that substituting mango provender ans and mango seed flour for maize resulted in rations with costs per kgMS of 215.35FCFA, 2016.93FCFA and 320FCFA for the ED10, ED20 and CCD rations respectively. The production costs per kg of chicken (FCPkgLW) of the CCD ration were significantly higher than those of the ED10 and ED20 (p 0.05). ADGs were significantly different and decreasing from CCD, ED20 to ED10 (p 0.05). Average weights at 42nd day for ED20 and CCD were homogeneous (p > 0.05) and significantly higher than for ED10 (p 0.05). By day 49th the average weight of ED20 had reached and exceeded that of CCD by day 42nd. PSLW, HCW and CCW were significantly different and decreasing from CCW, ED20 to ED10 (p 0.05). Average hot (HCY) and cooled (CCY) carcass yields of ED20 and CCD rations were comparable (p > 0.05) and significantly higher than those of ED10 ration (p = 0.009) and 0.003). Average drumstick and neck weights were significantly higher and lower for CCD, ED20 and ED10 (p 0.05). For all other parts of the cut, the average weights of the CCD ration were significantly higher (p 0.05) than those of the ED20 and ED10 rations, which were homogeneous (p 0.05). The incorporation of mango provender and mango seed flour in broiler rations offers the prospect of reduced production costs, less competition between man and animals over cereals, and lean meat production that is more appreciated than that of chickens fed conventional feed. As it stands, the ED20 ration can be recommended as a growth diet for broilers. It would be necessary to determine the levels of anti-nutritional substances in mango feeds and to assess the in vivo digestibility of mango ingredients and the diets incorporating them.

Effects of the Compatibility of Chinese Medical Herbs on Health and Growth Performance of Broilers

[Objective] The aim of this study is to investigate the effects of Chinese medical herbs including astragali and taraxacum on health and growth performance of broilers.[Method] The tested Chinese medical herbs were added into the basal diet of avian broilers for measuring the variation of their health and growth performance.[Result]Compared to the control group(fed by basal diet and with antibiotics as additive),the body weight of broilers fed by compatibility A(0.8% astragali;0.4% haw;0.4% dried citrus peel;0.4% rhizoma atractylodis)and by compatibility B(1.2% taraxacum;0.8% smoked plums;0.8% amur cork-tree bark;0.4% astragali)increased by 6.12%(P<0.01)and 0.64%(P>0.05),respectively;feed intakes changed by-7.95% and 9.99%,respectively;feed conversion rates changed by-14.04% and 9.35%,respectively.The survival rate of compatibility B was similar to that of control group.[Conclusion]Compatibility of Chinese medical herbs containing astragali can improve the growth performance of avian broilers,and that containing taraxacum may to some extent result in the decrease of growth performance,but it can play the role instead of antibiotic additives.

Muscular Histological Traits and Meat Tenderness of Different Local Broilers

Objective＇ To study the muscular histological traits and their relationship with meat tenderness in local broilers and provide a theoretical basis for promoting meat quality of broiler. [Methed] The diameter and density of muscle fiber of three local varieties of chicken （Beijing Fatty broil- er, Fujian Hetian broiler and Taining Black broiler） were detected at the age of 8 weeks, 12 weeks and 16 weeks. And the differences in the diame- ter and density of muscle fiber as well as their relationship with meat tenderness were respectively analyzed with SAS software. [ Resultl Fatty broil- er had the smallest muscle fiber diameter while Hetian broiler the largest; Fatty broiler had the highest muscle fiber density while Hetian broiler the lowest Hetian broiler had the highest muscle shear force of leg muscle while Black broiler the lowest （ P 〈0.05） ; Black broiler had the highest mus- cle shear force of breast muscle while Fatty broiler the lowest （P〈0.05）. The correlation analysis showed that the shear force of breast muscle and leg muscle had significantly positive relation with fiber diameter and significantly negative relation with fiber density （ P 〈 0.05）. [ Conclusion] Muscu- lar histological traits varied in different local broilers, and the muscular shear force had significantly relation with fiber diameter and density.

Effect of deffrent level of ZnMet on performance and immunity of broilers

试验采用完全随机试验设计，将1日龄的罗斯308肉鸡360只分成6组，每组3个重复，每个重复20只鸡，研究蛋氨酸锌（ZnMet）对肉鸡平均日增重（ADG）、平均日采食量（ADFI）和料重比（F／G）以及免疫器官指数和ND抗体效价的影响。目粮处理组为在不添加锌的玉米-豆粕型基础饲粮基础上分别添加20、40、60、80和100mg／kg水平的蛋氨酸锌（以锌计），结果表明，饲粮中添加蛋氨酸锌能提高肉鸡的平均日增重，改善料重比和免疫功能，60～80mg／kg为适宜添加量。

Effects of Lactobacillus acidophilus on the growth performance and intestinal health of broilers challenged with Clostridium perfringens

Background: Clostridium perfringens is the main etiological agent of necrotic enteritis. Lactobacil i show beneficial effects on intestinal health in infectious disease, but the protective functions of lactobacil i in C. perfringens-infected chickens are scarcely described. This study examined the effects of Lactobacil us acidophilus(L. acidophilus) on the growth performance and intestinal health of broiler chickens chal enged with Clostridium perfringens(C. perfringens) over a 28-day period. Using a 2 × 2 factorial arrangement of treatments, a total of 308 1-day-old male Arbor Acres broiler chicks were included to investigate the effects of Lactobacil us acidophilus(L. acidophilus) on the growth performance and intestinal health of broiler chickens chal enged with Clostridium perfringens(C. perfringens) during a 28-day trial.Results: During infection(d 14–21), C. perfringens challenge decreased the average daily gain(P < 0.05), and increased feed conversion ratio and the mortality rate(P < 0.05). However, dietary supplementation with L. acidophilus increased the body weight of C. perfringens-infected broilers on d 21(P < 0.05), and tended to decrease the mortality(P = 0.061).C. perfringens challenge decreased the villus height(P < 0.05), the ratio of villus height to crypt depth(P < 0.05) and OCLN(occludin) m RNA expression(P < 0.05), and increased the pro-inflammatory cytokine expression in the spleen and jejunum, the intestinal populations of C. perfringens and Escherichia(P < 0.05), and the serum content of endotoxin(P < 0.05), regardless of L. acidophilus supplementation. In contrast, dietary L. acidophilus reducedthe intestinal lesion score of challenged broilers(P < 0.05), the m RNA expression of pro-inflammatory cytokines, ileal populations of Escherichia and serum endotoxin content(P < 0.05), but increased the intestinal Lactobacillus populations(P < 0.05),irrespective of C. perfringens challenge.Conclusion: Dietary addition of L. acidophilus could improve the intestinal health and reduce the mortality of broilers suffering from necrotic enteritis.

Effects of dietary graded levels of cinnamon essential oil and its combination with bamboo leaf flavonoid on immune function, antioxidative ability and intestinal microbiota of broilers

Cinnamon essential oil(CEO)and its combination with bamboo leaf flavonoid(BLF)have been shown to exhibit an additive antibacterial effect in vitro,but their functions in broilers were not clear.An experiment was conducted to investigate the effects of dietary graded levels of CEO and its combination with BLF on the growth performance,immune responses,antioxidative ability,and intestinal morphology and microbiota of broilers fed a corn-soybean meal basal diet.A total of 576 1-d-old Arbor Acres commercial male broilers were randomly allotted to 9 treatments with 8 replicates of 8 birds each in a completely randomized design.Birds were fed on a basal corn-soybean meal diet(control,without plant extracts and antibiotics),or the basal diet supplemented with 50 mg of aureomycin kg^-1,50,100,200,400,or 800 mg of CEO kg^-1,a combination of 100 mg of CEO and 16.7 mg of BLF kg^-1,or a combination of 200 mg of CEO kg^-1 and 33.3 mg of BLF kg^-1 for 42 d.Dietary treatment affected(P<0.05)the serum immune globulin M(IgM)contents on d 42,liver malondialdehyde(MDA)contents on d 21,duodenal crypt depth on d 42,relative abundance of Lactobacillus in the cecal contents on d 21,and relative abundances of Escherichia coli and Bifidobacterium in the cecal contents on d 42,but had no effect(P>0.16)on all other measured indices.The addition of 400 mg of CEO kg^-1 or a combination of 200 mg CEO kg^-1 and 33.3 mg BLF kg^-1 increased(P<0.02)serum IgM contents on d 42.Dietary supplementation with 100 or 200 mg CEO kg^-1,or 50 mg aureomycin kg^-1 decreased(P<0.003)liver MDA contents on d 21.In addition,the supplement of 100 mg CEO kg^-1 increased(P<0.002)the Lactobacillus relative abundance in caecum on d 21 and Bifidobacterium relative abundance in caecum on d 42,and decreased(P<0.0001)E.coli relative abundance in caecum on d 42.The results indicated that dietary supplementation with CEO,an alternative to aureomycin,improved the immune status,antioxidantative ability and cecal microbiota of broilers,and dietary supplementation with the combinations of CEO and BLF did not exhibit further effects.Dietary supplementation with 100 mg CEO kg^-1 is beneficial for broilers fed a corn-soybean meal basal diet.

Effectiveness of dietary xylo-oligosaccharides for broilers fed a conventional corn-soybean meal diet

An experiment was conducted to investigate the effect of dietary supplementation of xylo-oligosaccharides（XOS） on growth performance, meat quality, immune functions, duodenal morphology and intestinal microbial populations of broilers fed a conventional corn-soybean meal basal diet. A total of 450 1-day-old commercial Arbor Acres male broiler chicks were randomly allocated by bodyweight to 1 of 5 treatments with 6 replicate cages（15 broilers per cage） for each of 5 treatments in a completely randomized design. Chicks were fed the basal corn-soybean meal diets supplemented with 0, 25, 50, 75, or 100 mg of XOS kg–1 of diet, respectively, for an experimental duration of 42 days. The results showed that supplementation of XOS affected feed conversion rate（feed/gain, F/G） during days 22–42 and 1–42（P〈0.03）, drip loss in thigh muscle（P=0.02）, and duodenal crypt depth（P=0.005） on day 42, but had no effect（P〉0.05） on all other measured indices. The chicks fed the diet supplemented with 100 mg of XOS kg–1 had the lowest（P〈0.05） F/G and drip loss in thigh muscle. The drip loss in thigh muscle decreased linearly（P=0.003） as the supplemented XOS increased. Duodenal crypt depth decreased（P〈0.05） at the supplemental level of 75 mg of XOS kg–1. The results indicate that dietary supplementations of 75 and 100 mg of XOS kg–1 are beneficial to broilers fed a conventional corn-soybean meal diet.

Effect of Methionine Deficiency on the Thymus and the Subsets and Proliferation of Peripheral Blood T-Cell,and Serum IL-2 Contents in Broilers

The purpose of this study was to investigate the effects of methionine deficiency on cellular immune function by determining morphological and ultrastructural changes of thymus, thymic cell cycle and apoptosis, peripheral blood T-cell subsets, T- cell proliferation function and the serum interleukin-2 （IL-2） contents. 120 1-d-old broilers were randomly divided into two groups （6 replicates in each group and l0 broilers in each replicate） and fed on a control diet or methionine deficient diet for 42 d. Lesions were observed in experiment. Histopathologically, lymphopenia and congestion were observed in the medulla of thymic lobule. Ultrastructurally, there were more apoptosis lymphocytes, and the mitochondria of lymphocytes were swelled in thymus of methionine deficiency. The G0/G~ phase of the cell cycle of the thymus was much higher （P〈0.01）, and the S, G2＋M phases and proliferating index （PI） were lower （P〈0.01） in methionine deficiency than in control group. And the percentage of apoptotic cells in the thymus was significantly increased in methionine deficiency （P〈0.01）. The percentage of CD4＋ and CD8~ T-cells was decreased in methionine deficiency compared with control group. Meanwhile, the proliferation function of peripheral blood T-cell was decreased in methionine deficiency. Also, the serum IL-2 contents were decreased in methionine deficiency. It was concluded that methionine deficiency could cause pathological and ultrastructural changes of thymus, reduce the T-cell population, serum IL-2 contents and the proliferation function of T- cells, and induce increased percentage of apoptotic cells. The cellular immune function was finally impaired in broilers.

Effects of dietary tryptophan and stocking density on the performance,meat quality,and metabolic status of broilers

Background： Highly automated cage-rearing systems are becoming increasingly popular in China. However, a high stocking density can cause oxidative stress and decrease broiler performance. The tryptophan （TRP） derivative 5-hydroxytryptophan （5-HT） has been shown to preserve membrane fluidity in birds suffering from oxidative stress Therefore, this experiment was conducted to determine the effects of dietan/TRP supplementation on performance, breast meat quality and oxidative stress in broilers reared in cages with a high or low stocking density. Methods： Female Arbor Acres broilers （25-d-old, n = 144） were randomly allocated to 1 of 4 treatments. The birds were fed a diet based on corn, soybean meal, cottonseed meal and corn gluten meal containing either 0.18 or 0.27% TRP and were housed with stocking densities of 11 or 15.4 birds/m2 in a 2 x 2 factorial experiment. Broiler performance was evaluated from d 25 to 42. Eight birds from each treatment were slaughtered on d 42 and plasma and breast muscle samples were collected to measure biochemical indices. Results： A higher stocking density tended to be associated with reduced weight gain （P 〈 0.10）, and significantly increased plasma glutamic-pyruvic transaminase （GPT） activity （P 〈 0.001）. Increased dietary TRP significantly reduced the activities of lactic dehydrogenase and GPT while increasing total cholesterol in the plasma （P 〈 0.01）, reducing drip loss of breast muscle （P 〈 0.10） and improving feed efficiency （P 〈 0.10）. Conclusions： An increase in dietary TRP, ].S-fold higher than the standard supplementation level, can alleviate oxidative stress as well as improve welfare and feed efficiency in broilers reared in cages with a high stocking density.