This study evaluated the effects of dietary genistein supplementation on laying performance, eggshell quality, antioxidant capacity, and ovarian steroidogenesis in 66-week-old Hy-Line Brown laying hens. A total of 384 hens were randomly allocated to four treatments: a basal diet (control) or diets supplemented with 80, 120, or 400 mg/kg genistein, with 6 replicates of 16 birds each. Genistein supplementation at all levels significantly increased laying rate and reduced feed conversion ratio and broken egg rate (P < 0.05). Regarding egg quality, 80 and 120 mg/kg genistein decreased egg shape index, while all treatments increased shell ratio, and 80 mg/kg enhanced blunt-end shell thickness (P < 0.05). Plasma superoxide dismutase (SOD) activity was elevated by 80 and 400 mg/kg genistein (P < 0.05). In the liver, all genistein treatments increased SOD, glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC), and reduced malondialdehyde (MDA) levels (P < 0.05). In the ovary, 80 mg/kg increased GSH-Px activity, while 80 and 400 mg/kg enhanced catalase (CAT) activity (P < 0.05). Moreover, 80 and 120 mg/kg genistein increased plasma progesterone (P4) concentrations (P < 0.05). Expression of steroidogenic genes was also upregulated, with increased mRNA levels of steroidogenic acute regulatory protein (StAR), cytochrome P450 side-chain cleavage enzyme (CYP11A1), and 3β-hydroxysteroid dehydrogenase (3β-HSD). Corresponding increases in protein abundance were observed for StAR, CYP11A1, and 3β-HSD at specific supplementation levels (P < 0.05). In conclusion, dietary genistein improved laying performance and selected eggshell quality traits, enhanced antioxidant capacity, and was associated with increased plasma progesterone concentrations and altered expression of ovarian steroidogenesis-related factors in late-laying hens.

IntroductionThe intestinal dysfunction plays an important role in the decreased growth performance of broiler chickens under high stocking density. Gut microbiota plays an important role in maintaining intestinal health. However, the modulation pathway of gut microbiota by regulating the intestinal barrier and histomorphology remains unknown.MethodsOne hundred and forty-four male Arbor Acres broilers (22-d-old) with similar weight were randomly assigned to two treatments: a high (HSD, 20 broilers/m2) or low stocking density treatment (LSD, 14 broilers/m2), with six replicates per treatment. The experimental period was 20 days, from 22 to 42 days of age.ResultsThe final body weight at 42 days of age was lower in the HSD group (P = 0.0013) and average daily feed intake (P = 0.016) and weight gain of broilers from 22 to 42 days decreased (P = 0.012). In the HSD group on day 42, villus height and the ratio of villus height to the crypt depth in the ileum decreased (P < 0.05); mRNA expression of tight junction proteins, occludin (P < 0.01) and ZO1 (P < 0.05), were downregulated; whereas IL-6, TNFα, and NFκB p65 (P < 0.05) and IL-1β (P < 0.01) were upregulated. The HSD treatment increased the relative abundance of Lactobacillus (P = 0.045) and decreased that of Alistipes (P = 0.031). Cecal concentrations of acetic (P < 0.05) and butyric acids (P < 0.05) decreased. Gut metabolites co-metabolized by the host and gut microbiota were altered in the HSD group, with decreases in glycerophospholipid and tryptophan metabolites negatively correlated with Lactobacillus (P < 0.05). The metabolite content of conjugated bile acids decreased and free bile acids increased (P < 0.05) with HSD. Bile salt hydrolase (BSH) was increased in the intestine of HSD-treated broilers (P < 0.01). The total cholic acid content of the HSD group was lower in the jejunum and ileum (P < 0.05) but higher in the cecum than in the LSD group (P < 0.01).ConclusionHSD caused dysbiosis of the intestinal microbiota such as increased Lactobacillus, along with enhanced BSH activity and excessive unabsorbed free bile acids. This resulted in ileal epithelial cells damage, inflammation, decreased growth performance of broilers under high stocking densities.

The liver of hens bears a very heavy workload in handling lipogenesis as well as carbohydrate, protein, and other nutrient metabolism to maintain a high laying rate. D-glucuronolactone (DGL) is a naturally occurring chemical metabolite produced from glucose and exhibits a hepatoprotective effect as a food ingredient. This study aimed to evaluate the effect of DGL on production performance, egg quality, and liver health in laying hens during their peak period. Four hundred and eighty Hy-Line brown hens (aged 42 weeks), with comparable high-laying performance, were randomly assigned to four groups, with each group consisting of eight replicates. The control group was fed a basal diet, while the treatment groups were supplemented with DGL at 70, 140, and 280 mg/kg in the basal diet, respectively. The results indicated that DGL supplementation significantly increases the laying rate and egg mass of hens (p < 0.05). The brown color of the eggshell was significantly deepened by DGL administration (p < 0.05). Additionally, DGL supplementation significantly decreased the serum levels of aspartate aminotransferase and γ-glutamyl transpeptidase (p < 0.05). The liver index, liver fat, and triglyceride levels in the liver had also significantly decreased (p < 0.05). Liver histopathological results showed that the control group exhibited yellow coloration with large gaps and numerous vacuolar cells, while DGL supplementation improved the compactness of liver parenchyma. Antioxidant activity was enhanced, showing a significant increase in the activity of total antioxidant capacity and catalase in the liver (p < 0.05). The inflammatory response was alleviated, with a significant decrease in expressions of interleukin-β, tumor necrosis factor-α, interferon-α, interleukin-6, and interleukin-8 genes in the liver (p < 0.05). Moreover, DGL supplementation significantly reduced cell apoptosis-related genes, including factor-related apoptosis, Caspase 7, and BCL2 associated X protein in the liver (p < 0.05). Overall, these findings indicate that dietary DGL enhanced the laying performance of hens by maintaining liver health, with the best results achieved at a dose of 280 mg/kg in this trial.

本试验旨在研究蛋氨酸锌对肉鸡生长性能、抗氧化能力和免疫功能的影响.选取体重相近的1日龄爱拔益加(AA)雄性肉鸡336只,随机分4个组,每组7个重复,每个重复12只鸡.各组蛋氨酸锌添加水平分别为0(对照组)、20(T20组)、40(T40组)和80 mg/kg(T80组).试验期共42 d,分为1～21日龄和22～42日龄2个阶段.结果表明:1)与对照组相比,T40和T80组肉鸡21日龄体重显著升高(P＜0.05),T4 0和T80组肉鸡1～21日龄平均日增重显著升高(P＜0.05),T20、T40和T80组肉鸡1～21日龄料重比显著降低(P＜0.05).饲粮蛋氨酸锌添加水平为51 mg/kg时,肉鸡1～21日龄料重比最低.2)各组之间肉鸡21和42日龄血清超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性及丙二醛(MDA)含量无显著差异(P＞0.05).3)各组之间肉鸡21和42日龄免疫器官指数无显著差异(P＞0.05).与对照组相比,T20、T40和T80组肉鸡21日龄血清白细胞介素-6含量显著降低(P＜0.05),T40和T80组肉鸡42日龄血清白细胞介素-6含量显著降低(P＜0.05).综上所述,饲粮中添加蛋氨酸锌可提高肉鸡生长性能和免疫功能.在本试验条件下,以料重比为评定指标,饲粮蛋氨酸锌的适宜添加水平为51 mg/kg.

As a foodborne pathogen of global importance, Salmonella enterica serovar Enteritidis (S. Enteritidis) is a threat to public health that is mainly spread by poultry products. Intestinal Enterobacteriaceae can inhibit the colonization of S. Enteritidis and are regarded as a potential antibiotic substitute. We investigated, in chicks, the anti-S. Enteritidis effects of Escherichia coli (E. coli) Nissle 1917, the most well-known probiotic member of Enterobacteriaceae. Eighty 1-d-old healthy female AA broilers were randomly divided into 4 groups, with 20 in each group, namely the negative control (group P), the E. coli Nissle 1917-treated group (group N), the S. Enteritidis-infected group (group S) and the E. coli Nissle 1917-treated and S. Enteritidis-infected group (group NS). From d 5 to 7, chicks in groups N and NS were orally gavaged once a day with E. coli Nissle 1917 and in groups P and S were administered the same volume of sterile PBS. At d 8, the chicks in groups S and NS were orally gavaged with S. Enteritidis and in groups P and N were administered the same volume of sterile PBS. Sampling was conducted 24 h after challenge. Results showed that gavage of E. coli Nissle 1917 reduced the spleen index, Salmonella loads, and inflammation (P < 0.05). It improved intestinal morphology and intestinal barrier function (P < 0.05). S. Enteritidis infection significantly reduced mRNA expression of angiotensin-converting enzyme 2 (ACE2) and solute carrier family 6-member 19 (SLC6A19) in the cecum and the content of Gly, Ser, Gln, and Trp in the serum (P < 0.05). Pretreatment with E. coli Nissle 1917 yielded mRNA expression of ACE2 and SLC6A19 in the cecum and levels of Gly, Ser, Gln, and Trp in the serum similar to that of uninfected chicks (P < 0.05). Additionally, E. coli Nissle 1917 altered cecum microbiota composition and enriched the abundance of E. coli, Lactobacillales, and Lachnospiraceae. These findings reveal that the probiotic E. coli Nissle 1917 reduced S. Enteritidis infection and shows enormous potential as an alternative to antibiotics.

脂肪肝是动物常见的脂类代谢性疾病,它的发生与动物肝脏脂肪代谢紊乱有着密不可分的关系,可导致蛋鸡产蛋率严重下降、奶牛酮病和母猪胎衣不下等,给养殖业造成巨大的经济损失.褪黑素可参与脂肪代谢调节,缓解脂肪代谢紊乱,其在生产实践中的应用前景越来越广阔.本文介绍了脂肪肝产生的原因及机制,综述了褪黑素参与脂类代谢的机理以及外源褪黑素改善动物脂肪肝的研究进展,为褪黑素在畜牧业中的应用提供参考.

为研究不同来源铜对肉鸡生产性能和肠道发育的影响,选用1日龄AA白羽肉鸡384只,随机分为3组,每组8个重复,每个重复16只鸡,试验周期42 d.对照组饲喂基础日粮,基础日粮中无外源铜添加,处理组在基础日粮中分别添加140 mg/kg硫酸铜和60 mg/kg碱式氯化铜(Tribasic copper chloride,TBCC),两组铜实际添加量均为35 mg/kg.结果显示:与对照组和硫酸铜组相比,TBCC组可显著降低肉鸡死亡率,提高欧洲效益指数(P＜0.05),且TBCC组肉鸡粪便中的铜含量显著低于硫酸铜组(P＜0.05);TBCC可显著升高肉鸡空肠21日龄的绒毛高度和绒隐比(P＜0.05),有升高42日龄肉鸡空肠绒隐比的趋势(P=0.058),显著升高肉鸡21日龄空肠杯状细胞数量(P＜0.05),显著升高21日龄和42日龄空肠黏膜封闭蛋白1的表达量(P＜0.05),显著降低21日龄肉鸡空肠黏膜封闭蛋白3的表达(P＜0.05),有提高42日龄肉鸡空肠黏膜密闭蛋白表达的趋势(P=0.068).结果表明:添加TBCC对肉鸡死亡率和欧洲效益指数的影响优于硫酸铜,原因可能与TBCC对肉鸡肠道黏膜形态和肠道屏障的促进作用有关.

本试验旨在研究不同添加方式的酸化剂对肉鸡生长性能和肠道发育的影响.选择1日龄、体重接近的健康白羽肉鸡512只,随机分为8组,每组8个重复,每个重复16只鸡.正常对照组(NC组)饲喂基础饲粮和基础饮用水,阳性对照组(PC组)饲喂基础饲粮+20 mg/kg维吉尼亚霉素和基础饮用水,饮水酸化剂组(WA组)饲喂基础饲粮和基础饮用水中添加0.1％酸化剂,饲粮酸化剂组(FA组)饲喂基础饲粮+0.2％酸化剂和基础饮用水.试验期42 d.结果表明:1)与NC组相比,WA和FA组的欧洲效益指数显著提高(P＜0.05),且与PC组无显著差异(P＞0.05).与NC组相比,FA组的死亡率显著降低(P＜0.05).2)与NC组相比,WA和FA组的21日龄十二指肠隐窝深度显著降低(P＜0.05),21和42日龄十二指肠绒隐比显著提高(P＜0.05),且与PC组无显著差异(P＞0.05).与NC组相比,FA组的42日龄空肠绒隐比显著提高(P＜0.05),21日龄回肠绒隐比显著提高(P＜0.05),且与PC组无显著差异(P＞0.05).3)与NC组相比,FA组的21日龄十二指肠和空肠杯状细胞数量显著提高(P＜0.05),42日龄空肠杯状细胞数量显著提高(P＜0.05).与NC组相比,WA和FA组的21日龄空肠封闭蛋白-2的mRNA相对表达量均显著提高(P＜0.05),FA组的21和42日龄空肠封闭蛋白-3的mRNA相对表达量显著提高(P＜0.05).由此可见,酸化剂通过饲粮添加和饮水添加对肉鸡生长性能的促进作用与抗生素相当,对肠道发育的促进作用优于抗生素;酸化剂通过饲粮添加对肉鸡生长性能和肠道发育的改善作用优于饮水添加.

The present study was conducted to evaluate the effects of lecithin on the performance, meat quality, lipid metabolism, and cecum microbiota of broilers. One hundred and ninety-two one-day-old AA broilers with similar body weights (38 ± 1.0 g) were randomly assigned to two groups with six replicates of sixteen birds each and were supplemented with 0 and 1 g/kg of lecithin for forty-two days. Performance and clinical observations were measured and recorded throughout the study. Relative organ weight, meat quality, lipid-related biochemical parameters and enzyme activities were also measured. Compared with broilers in the control group, broilers in the lecithin treatment group showed a significant increase in L* value and tenderness (p < 0.05). Meanwhile, the abdominal adipose index of broilers was markedly decreased in lecithin treatment after 42 days (p < 0.05). In the lipid metabolism, broilers in the lecithin treatment group showed a significant increase in hepatic lipase and general esterase values at 21 days compared with the control group (p < 0.05). Lower Firmicutes and higher Bacteroidetes levels in phylum levels were observed in the lecithin treatment group after 21 and 42 days. The distribution of lactobacillus, clostridia, and rikenella in genus levels were higher in the lecithin treatment group after 21 and 42 days. No statistically significant changes were observed in performance, relative organ weight, or other serum parameters (p > 0.05). These results indicate that supplementation with lecithin significantly influence the lipid metabolism in broilers at 21 and 42 days, which resulted in the positive effect on the meat color, tenderness, and abdominal adipose in broilers.

<span id="ChDivSummary" name="ChDivSummary" class="abstract-text">本试验旨在研究饲粮添加橡椀单宁对肉鸡生长性能、屠宰性能、肉品质、抗氧化功能和肠道发育的影响。选取1日龄雄性爱拔益加（AA）肉鸡288羽,随机分为4组,每组6个重复,每个重复12羽。对照组（VT-0组）饲喂基础饲粮,试验组分别在基础饲粮中添加100（VT-1组）、500（VT-2组）和1 000 mg/kg（VT-3组）橡椀单宁。试验期42 d。结果表明:1)饲粮添加橡椀单宁对肉鸡生长性能无显著影响（P&gt;0.05）。2)VT-3组肉鸡屠宰率显著高于其他各组（P&lt;0.05）,VT-1和VT-2组肉鸡爪重率显著高于VT-0组（P&lt;0.05）。3) VT-3组肉鸡胸肌系水力显著高于VT-0和VT-1组（P &lt;0.05）。4) VT-1、VT-2和VT-3组42日龄肉鸡血清过氧化氢酶（CAT）活性和总抗氧化能力（T-AOC）显著高于VT-0组（P&lt;0.05）。VT-2和VT-3组42日龄肉鸡胸肌超氧化物歧化酶（SOD）活性显著高于VT-0组（P&lt;0.05）。5)VT-1和VT-2组42日龄肉鸡空肠绒毛高度显著高于VT-0组（P&lt;0.05）。VT-1、VT-2和VT-3组42日龄肉鸡回肠绒毛高度显著高于VT-0组（P&lt;0.05）。由此可见,饲粮添加橡椀单宁能够提高42日龄肉鸡抗氧化功能,改善肉品质,提高空肠和回肠绒毛高度,且饲粮添加1 000 mg/kg橡椀单宁能提高肉鸡屠宰率。综合各项指标,推荐橡椀单宁的添加量为1 000 mg/kg。</span>

[This corrects the article DOI: 10.1098/rsos.191561.].

Autophagy is an important component of the innate immune system in mammals. Low levels of basic autophagy are sustained in normal cells, to help with the clearance of aging organelles and misfolded proteins, thus maintaining their structural and functional stability. However, when cells are faced with challenges, such as starvation or pathogenic infection, their level of autophagy increases significantly. Salmonella is a facultative intracellular pathogen, which imposes an economic burden on the poultry farming industry and human public health. Previous studies have shown that Salmonella can induce the autophagy of cells following invasion, which to a certain extent helps to protect the cells from bacterial colonization. This review summarizes the latest research in the field of Salmonella-induced autophagy, including: i) the autophagy induction and escape mechanisms employed by Salmonella during the infection of host cells; ii) the effect of autophagy on intracellular Salmonella; iii) the important autophagy adaptors that recognize intracellular Salmonella in host cells; and iv) the effect of autophagy-modulating drugs on Salmonella infection.

Magnetic Fe3O4 nanoparticles (Fe3O4-NPs) have been widely investigated for their biomedical applications. The main purpose of this study was to evaluate the cytotoxic effects of different sizes of Fe3O4-NPs in chicken macrophage cells (HD11). Experimental groups based on three sizes of Fe3O4-NPs (60, 120 and 250 nm) were created, and the Fe3O4-NPs were added to the cells at different doses according to the experimental group. The cell activity, oxidative index (malondialdehyde (MDA), superoxide dismutase (SOD) and reactive oxygen species (ROS)), apoptosis and pro-inflammatory cytokine secretion level were detected to analyse the cytotoxic effects of Fe3O4-NPs of different sizes in HD11 cells. The results revealed that the cell viability of the 60 nm Fe3O4-NPs group was lower than those of the 120 and 250 nm groups when the same concentration of Fe3O4-NPs was added. No significant difference in MDA was observed among the three Fe3O4-NP groups. The SOD level and ROS production of the 60 nm group were significantly greater than those of the 120 and 250 nm groups. Furthermore, the highest levels of apoptosis and pro-inflammatory cytokine secretion were caused by the 60 nm Fe3O4-NPs. In conclusion, the smaller Fe3O4-NPs produced stronger cytotoxicity in chicken macrophage cells, and the cytotoxic effects may be related to the oxidative stress and apoptosis induced by increased ROS production as well as the increased expression of pro-inflammatory cytokines.

<span id="ChDivSummary" name="ChDivSummary" class="abstract-text">本试验旨在检测黄花蒿发酵粉对肉仔鸡生长性能的影响,并以抗球虫药物（地克株利）为对照,检测其抗鸡盲肠型柔嫩艾美耳球虫（Eimeria tenella）感染的功效。试验选取1日龄体重相近的雪山草鸡公鸡270羽,随机分为对照组和3个试验组;饲养试验时间为21 d,对照组饲喂基础饲粮,试验组分别饲喂添加0.4%、0.8%和1.2%黄花蒿发酵粉的基础饲粮,每周称取体重。在14日龄时,对照组随机分为3个亚组,即阴性对照亚组（不感染+不给药）、阳性对照亚组（感染+不给药）和抗球虫药物（地克株利）对照亚组（感染+给药）;各个试验组随机分为2个亚组,即阴性试验亚组（不感染+不给药）和阳性试验亚组（感染+不给药）,此时每亚组有2个重复,每个重复15羽鸡。在15日龄时进行攻虫,感染亚组每羽鸡口服1 mL含10⁵个/mL柔嫩艾美尔球虫卵囊的重铬酸钾水溶液。在21日龄时称取体重,计算死亡率,称取胸浅肌和腓肠肌外侧头重,进行盲肠病变评分和卵囊排出量计数。结果表明:1)黄花蒿发酵粉对鸡只7、14和21日龄的体重和体增重及21日龄的骨骼肌重均有极显著的影响（P&lt;0.01）。2)感染盲肠型球虫第7天,饲喂添加0.8%黄花蒿发酵粉的感染鸡只的体重和骨骼肌重,与阴性对照亚组的非感染鸡无显著差异（P&gt;0.05）。3)黄花蒿发酵粉可显著降低感染鸡的血便数量和盲肠病变评分（P &lt;0.05）,减少球虫卵囊排出数量;含0.8%黄花蒿发酵粉的饲粮的抗球虫指数达到139,属于低效抗球虫药物,而含0.4%和1.2%黄花蒿发酵粉的饲粮的抗球虫指数低于120,判定为无抗盲肠型球虫的效果。综上所述,饲粮中添加黄花蒿发酵粉能提高肉仔鸡的生长性能,且有剂量依赖效应;黄花蒿发酵粉可以降低盲肠型球虫感染肉仔鸡的卵囊排出量,缓解肠道黏膜损伤,含0.8%黄花蒿发酵粉的饲粮具有一定的抗球虫效果。</span>

<span id="ChDivSummary" name="ChDivSummary" class="abstract-text">本试验旨在研究枯草芽孢杆菌对肉鸡生长性能、抗氧化功能和肠道形态的影响。选取1日龄雄性爱拔益加（AA）肉鸡420只,随机分为4组,每组7个重复,每个重复15只鸡。对照组饲喂基础饲粮,枯草芽孢杆菌组在基础饲粮中添加200 g/t枯草芽孢杆菌,杆菌肽锌组在基础饲粮中添加250 g/t杆菌肽锌,枯草芽孢杆菌+杆菌肽锌组在基础饲粮中添加200 g/t枯草芽孢杆菌和250 g/t杆菌肽锌。试验期42 d。结果表明,与对照组相比,饲粮中添加枯草芽孢杆菌显著提高了22～42日龄肉鸡的平均日增重（ADG）和血清丙二醛（MDA）含量（P&lt;0.05）,显著降低了1～21日龄肉鸡的ADG、平均日采食量（ADFI）及血清超氧化物歧化酶（SOD）活性和空肠隐窝深度（P&lt;0. 05）。饲粮中添加枯草芽孢杆菌和杆菌肽锌对22～42日龄肉鸡的料重比（F/G）、1～42日龄欧洲效益指数和肝脏MDA含量有显著交互作用（P&lt;0.05）。综上所述,饲粮中添加200 g/t的枯草芽孢杆菌能提高22～42日龄肉鸡的生长性能,在一定程度上改善肉鸡空肠黏膜形态;饲粮中添加200 g/t的枯草芽孢杆菌和250 g/t的杆菌肽锌能够提高肉鸡的生长性能。</span>

Recently nanomaterials have received substantial attention in biotechnology areas for their innovative properties in physical and chemical function. One of the most arrestive properties of nanomaterials that has been reported is their bacteriostatic activity. Our previous research found that Fe3O4 magnetic nanoparticles (Fe3O4-NPs) could effectively reduce the viability of intracellular Salmonella Enteritidis in chicken cells. There is an essential need to explore whether the bacteriostatic activity of Fe3O4-NPs is available in vivo. As an extension of this research, we conducted the present study to investigate the potential effect of Fe3O4-NPs used for S. Enteritidis control in chickens and to extensively investigate the underlying mechanisms in the process. The overall study included the evaluation of pathological sections, antioxidant status, inflammation, and the autophagy status of chicken liver, including the signaling pathway involved in the process. Results indicated that Fe3O4-NPs pretreatment can effectively inhibit the invasion of S. Enteritidis in chicken liver. Fe3O4-NPs pretreatment significantly increased reactive oxygen species (ROS) generation in chickens, including antioxidant enzyme activities. S. Enteritidis infection significantly increased the protein expression of the autophagy marker LC3. Additionally, the inflammation response and pathological changes caused by S. Enteritidis infection were alleviated by Fe3O4-NPs pretreatment. Phosphorylated mTOR was significantly increased in S. Enteritidis infected chickens, but showed no difference in chickens pretreated with Fe3O4-NPs. In summary, the results demonstrated that ROS and autophagy were involved in the inhibition of S. Enteritidis in chickens by Fe3O4-NPs pretreatment. The redox balance and inflammation response appeared normal in the process, as did the expression of the PI3K/Akt/mTOR signaling pathways. Taken together, our research demonstrate that the bacteriostatic activity of Fe3O4-NPs in chickens is avaliable and safe, which can be an alternative to antibiotics for bacterial inhibition in poultry industry.

This experiment was to study the effects of newly harvested corn on growth performance, intestine development and metabolism of nutrients in broilers. A total of 380 one-day-old Arbor Acres male broilers were assigned to ageing corn group (AC group), 1/3 newly harvested corn group (1/3 NC group), 2/3 newly harvested corn group (2/3 NC group), and newly harvested corn group (NC group), which according to the proportion of newly harvested corn in the total amount of corn of basal diets. Each group included six replicates with 16 birds. Digestion and metabolism trials were conducted at 39 to 42 days of age. Results showed that feed: gain ratio (F/G) of NC group was higher than that of 1/3 NC group and 2/3 NC group at 22 to 42 and 1 to 42 days of age (p < .05). The metabolic rates of calcium and phosphorus in NC group were lower than those in AC group, 1/3 NC group and 2/3 NC group (p < .05). In NC group, the relative weight of caecum was significantly higher than that in 2/3 NC group and AC group at 21 days of age (p < .05), while the relative weight of jejunum was lower than that in 2/3 NC group and AC group at 42 days of age (p < .05). In summary, newly harvested corn can reduce the growth performance and metabolism of some nutrients in broilers. Newly harvested corn should be controlled during actual production.Highlights Newly harvested corn can reduce the growth performance in broilers. Newly harvested corn can reduce apparent metabolic rate of calcium and phosphorus in broilers. Newly harvested corn can affect the intestine development in broilers.

The effects of N-carbamylglutamate (NCG) on the growth performance, tissue development, and blood parameters of broilers are unknown. In this study, 2 linked experiments were conducted to investigate the effects of 4 graded dietary levels and 3 dietary stages of NCG in a Chinese indigenous yellow-feather broiler breed during 2 growth phases: 1 to 18 d and 19 to 36 d. The dietary levels of NCG were 0.05%, 0.10%, 0.15%, and 0.20%, and dietary stages were designed to add NCG during the starter stage or grower stage or throughout the experimental period. At the age of 18 d, graded doses of NCG from 0.05 to 0.20% in the diet produced quadratic (P < 0.05) positive responses in body weight, width of intermuscular fat cingulum, liver weight, serum blood urea nitrogen, and serum low-density lipoprotein as well as linear (P < 0.05) positive responses in albumin serum concentration. The average feed per gain and mortality were unaffected by dietary NCG levels. Among 3 dietary treatments, only NCG dietary treatments throughout the experimental period improved the body weight and daily weight gain linearly (P < 0.05). The daily weight gain under the 3 dietary treatments used indicated that the most fitting dose is 0.1% NCG among the 4 dietary levels of NCG (P < 0.05). At this dose, muscle weight increased, whereas subcutaneous adipose as well as the serum contents of uric acid, triglyceride, and albumin decreased. Considering the growth performance and tissue development under the conditions used in this study, the best-fit model for NCG requirements of Chinese yellow-feather broilers was estimated from regression analysis to be 0.09 to 0.12% dietary NCG treatments during the grower stage. The modified blood parameters indicated that NCG dietary effects on broiler growth may be accompanied by modified homeostasis of arginine metabolism, lipid deposition, protein synthesis, and immune response.