Effects of rearing system and antibiotic treatment on immune function,gut microbiota and metabolites of broiler chickens

Background:In China,cage systems with a high space utilization have gradually replaced ground litter systems,but the disease incidence of chickens in cages is higher.Broilers in the ground litter pens may be stimulated by more environmental microbes during the growth process and show strong immune function and status,but knowledge of which microbes and their metabolites play an immunomodulatory role is still limited.This study aimed to explore the differences and correlations in the immune function,gut microbiota and metabolites and the importance of gut microbiota of broilers raised in cages and ground litter pens.Methods:The experiment involved a 2×2 factorial arrangement,with rearing systems(cages or ground litter pens)and antibiotic treatment(with or without broad-spectrum antibiotics in drinking water)as factors.Results:The results showed that,compared with the cage group,the ground litter broilers had stronger nonspecific immune function(Macrophages%and NO in blood),humoral immune function(IgG in blood,LPS stimulation index in ileum)and cellular immune function(T%,Tc%,ConA stimulation index and cytokines in blood).Antibiotic(ABX)treat-ment significantly reduced nonspecific immune function(Macrophages%and NO in blood,iNOS and Mucin2 mRNA expression in ileum),humoral immune function(IgG in blood and sIgA in ileum)and cellular immune function(T%and cytokines in blood,Th and Tc ratio,TLRs and cytokines mRNA expression in ileum).Furthermore,the ground litter broil-ers had higherαdiversity of microbiota in ileum.The relative abundance of Staphylococcus,Jeotgalicoccus,Jeotgalibaca and Pediococcus in the ileum of ground litter broilers were higher.ABX treatment significantly reduced theαdiversity of ileal microbiota,with less Chloroplast and Mitochondria.In addition,the levels of acetic acid,isobutyric acid,kynurenic acid and allolithocholic acid in the ileum of ground litter broilers were higher.Spearman correlation analysis showed that Jeotgalibaca,Pediococcus,acetic acid,kynurenic acid and allolithocholic acid were related to the immune function.Conclusions:There were more potential pathogens,litter breeding bacteria,short-chain fatty acids,kynurenine,allolithocholic acid and tryptophan metabolites in the ileum of broilers in ground litter pens,which may be the reason for its stronger immune function and status.

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.

Poultry fat decreased fatty acid transporter protein mRNA expression and affected fatty acid composition in chickens

Background： A study was undertaken to examine the effects of poultry fat （PF） compared with those of soybean oil （SBO） on intestinal development, fatty acid transporter protein （FATP） mRNA expression, and fatty acid composition in broiler chickens. A total of 144 day-old male commercial broilers were randomly allocated to 2 treatment groups （6 replicates of 12 chicks for each treatment） and fed isocaloric diets containing 3.0% PF or 2.7% SBO at 0 to 3 wk and 3.8% PF or 3.5% SBO at 4 to 6 wk, respectively. Results： PF had no influence on intestinal morphology, weight, or DNA, RNA, or protein concentrations at 2, 4, and 6 wk of age. However, compared with SBO, PF significantly decreased FATP mRNA abundance at 4 wk （P= 0.009） and 6 wk of age （P〈 0.001）; decreased liver fatty acid-binding protein （L-FABP） mRNA abundance at 6 wk of age （P = 0.039）; and decreased C18：2 （P = 0.015）, C18：3 （P 〈 0.001）, C20：2 （P = 0.018）, ∑-polyunsaturated fatty acids （∑-PUFA） （P= 0.020）, and the proportion of PUFA （P 〈 0.001） in the intestinal mucosa and decreased C18：2 （P = 0.010）, C 18：3 （P 〈 0.001 ）, C20：2 （P 〈 0.001 ）, Z-P U FA （P = 0.005）, and the proportion of P U FA （P 〈 0.001 ） in breast muscle at 6 wk of age.

安宁地区住院患儿呼吸道病原体七联检阳性检测结果分析

目的分析安宁地区住院患儿呼吸道感染病毒病原体阳性检测结果。方法选择2019年9月至2022年2月安宁地区住院患儿1766例为研究对象,根据年龄分为<6月龄组、6月龄~4岁组、4~14岁组;根据新冠疫情防控,2019年9月至2020年2月前为公众防护前,2020年2月后公众防护后;采集所有患儿鼻咽拭子标本,采用直接免疫荧光法测定甲型流感病毒抗原、乙型流感病毒抗原、呼吸道合胞病毒抗原、腺病毒抗原、副流感病毒Ⅰ型抗原、副流感病毒Ⅱ型抗原、副流感病毒Ⅲ型抗原7种呼吸道病原体,统计分析患儿呼吸道病原体检出情况。结果1766例患儿呼吸道感染病毒病原学检出阳性584例,阳性率为33.07%,呼吸道病毒病原体中检出主要以呼吸道合胞病毒(316例/17.89%)、腺病毒(90例/5.10%)、副流感病毒Ⅲ型(82例/4.64%)为主;患儿呼吸道感染病毒病原体阳性主要集中在<6月龄组、6月龄~4岁组,检出阳性率分别为111例(34.69%)、327例(34.31%),不同年龄段呼吸道感染病原体检测阳性率,差异有统计学意义(χ^(2)=8.392,P=0.031);公众防护后甲型流感病毒检出阳性率0.29%低于公众防护前5.94%,差异有统计学意义(P<0.05);公众防护前后乙型流感病毒抗原、腺病毒抗原、副流感病毒Ⅰ型、副流感病毒Ⅱ型、副流感病毒Ⅱ型检出率差异无统计学意义(P>0.05)。结论安宁地区住院患儿呼吸道感染病毒病原学检出率较高,呼吸道合胞病毒是主要病原体,公众防护后甲型流感病毒检出阳性率明显下降,故继续做好公众防护对防范甲型流感亦有重要意义。

Restricted feeding regimens improve white striping associated muscular defects in broiler chickens

The current study investigated the effects of intermittent feeding(IF)and fasting strategies at different times post–hatch on muscle growth and white striping(WS)breast development.In the first trial,32 one-day-old Abor Acre broilers were fed ad libitum(AL)for 3 d post–hatch and then randomly allotted into 4 feeding strategies including AL,1h-IF group(1 h IF,4 times feeding/d,1 h each time),1.5h-IF(1.5 h IF,4 times feeding/d,1.5 h each time),and fasting(1d acute fasting,6 d free access to feed)groups and fed for 7 d.Although angiogenic genes including VEGFA,VEGFR1,and VEGFR2,and myogenic genes including MYOG and MYOD were upregulated(P<0.05),the breast muscle satellite cell(SC)number and PAX7,MYF5 expression were decreased by the IF strategies(P<0.05).One-day fasting at 6 d of age also upregulated angiogenic genes and MYOD expression(P<0.05),downregulated MYF5 expression(P<0.05),but did not change SC number(P>0.05).In the second trial,384 one-day-old birds were fed AL for 1 wk and then randomly allotted to the above 4 feeding strategies starting at 8 d of age until 42 d of age.Similarly,IF and fasting strategies upregulated the expression of angiogenic and myogenic genes(P<0.05).Both 1h-IF and 1.5h-IF increased breast muscle SC number(P<0.05).At slaughter,breast muscle fiber diameter of 1.5h-IF was smaller but the SC number was larger than that of the birds fed AL(P<0.05).The IF and fasting strategies prevented WS development,and reduced breast WS scores and triglyceride content(P<0.05)without changing the body weight(P>0.05).Fasting and 1h-IF reduced the expression of adipogenic genes ZNF423 and PDGFRα(P<0.05).Moreover,IF and fasting strategies reduced fibrosis in breast muscle and reduced skeletal muscle-specific E3 ubiquitin ligases(TRIM63 and MAFBX)(P<0.05).Fasting significantly reduced CASPASE-3 in breast muscle(P<0.05).In conclusion,IF starting in the first week decreases SC number.Compared to AL,IF or fasting promotes muscular angiogenesis,increases SC number,prevents muscle degeneration,and prevents the development of WS without impairing the growth performance of broiler chickens.

The ionome and proteome landscape of aging in laying hens and relation to egg white quality

The ionome is essential for maintaining body function and health status by participating in diverse key biological processes.Nevertheless, the distribution and utilization of ionome among different organs and how aging impacts the ionome leading to a decline in egg white quality remain unknown. Thus, we used inductively coupled plasma mass spectrometry(ICP-MS) to analyze 35 elements and their isotopic contents in eight organs of laying hens at 35, 72, and 100 weeks. Moreover, the magnum proteome, amino acids in egg white, and egg white quality were analyzed in laying hens at three different ages using 4D proteomics techniques, an amino acid analyzer, and an egg quality analyzer. Across the organs, we identified varying distribution patterns among macroelements(Mg24, Ca43/44, K39, and P31), transition metals(Zn64/66, Cu63/65, Fe56/57, and Mn55), and toxic elements(Pb208, Ba137, and Sr86). We observed an organ-specific aging pattern characterized by the accumulation of toxic elements(Pb208, Ba137, and Sr86) and calcification in the small intestine. Additionally, a decrease in the utilization of essential trace elements selenium(Se78/82) and manganese(Mn55) was noted in the oviduct. By analyzing ionome in tandem with egg quality, egg white amino acids, and proteome, we unveiled that the reduction of selenium and manganese concentrations in the magnum during the aging process affected amino acid metabolism, particularly tryptophan metabolism, thereby inhibiting the amino acid synthesis in the magnum. Furthermore, it accelerated the senescence of magnum cells through necroptosis activation, leading to a decline in the albumen secretion function of the magnum and subsequently reducing egg white quality.Overall, this study provides insights into the evolution of 35 elements and their isotopes across 8 organs of laying hens with age.It also reveals the elemental composition, interactions, and utilization patterns of these organs, as well as their correlation with egg white quality. The present study highlights the significance of ionome and offers a comprehensive perspective on the selection of ionome for regulating the aging of laying hens.

Microbiome and ileum transcriptome revealed the boosting effects of selenium yeast on egg production in aged laying hens

The declines in laying performance during the late productionperiod have adverse effects on the length of theproduction cycle. Improving the nutrition of laying hens is a crucialmeasure to reverse this declination. Thisstudy investigatedthe effect of seleniumyeast (SY)on egg production, ileal gene expressionandmicrobiota, aswell as elucidating their associations in aged laying hens. A total of 375 Jinghong laying hens at 76weeks oldwere randomly assigned into 5 dietary treatments, which included a selenium-deficient basal diet based oncorn-soybean meal, and dietary supplementation of SY at 0.15, 0.30 and 0.45 mg/kg, and sodium selenite at0.45mg/kg.The results showed that SYamelioratedthe depressionin aged layingperformance inthe 0.30mg/kg group (P < 0.01). Selenium yeast significantly increased ileum selenium concentration (P < 0.05), and SYgroups had higher seleniumdeposition efficiency than the sodiumselenite group. Functional enrichment andShort Time-series Expression Miner (STEM) analysis indicated that SY activated metabolic progress (e.g.,glycerolipidmetabolism, glycerophospholipidmetabolism, andfattyacidmetabolism),immune responseandoxidative stress response. Four hub genes including thioredoxin reductase 1 (TXNRD1), dihydrolipoamidedehydrogenase (DLD), integrin linked kinase (ILK) and leucine zipper tumor suppressor 2 (LZTS2) wereinvolved in intestinal metabolismwhich was closely associated with selenium deposition/status. Moreover,the relative abundance of Veillonella, Turicibacter and Lactobacillus was significantly increased, but the relativeabundance of Stenotrophomonas was significantly decreased by SY supplementation. Multi-omics dataintegration and Canonical correspondence analysis (CCA) showed that both the ileumselenium content andthe laying rate were highly correlated with pathways and bacteria enriched in metabolism and immuneresponse. Meanwhile, the “switched on” gene prostate stem cell antigen (PSCA) had a positive relationshipwith Veillonella and a negative relationship with the opportunistic pathogens Stenotrophomonas. Overall, ourstudy offered insight for the further exploration of the role of SY on boosting egg production and balancingileum intestinal flora in aged laying hens.