日粮锌、硒水平对肉鸡肠道IgA+浆细胞分布的影响

为了探讨微量元素锌和硒互作对肉鸡肠道黏膜屏障结构的影响，将24只1日龄AA肉鸡随机分3组，分别饲喂添加有高锌高硒（锌1000mg／kg、硒5mg／kg）、低锌低硒（锌34mg／kg、硒0．08mg／kg）或常锌常硒（锌50mg／kg、硒0．15mg／kg）的日粮45d后，用免疫组化方法检测肠道内IgA^＋浆细胞及阳性反应物的数量及分布变化。结果表明；IgA^＋浆细胞及阳性物质散在分布于小肠绒毛顶端，固有层、肠腺周围以及盲肠黏膜固有层和盲肠扁桃体的淋巴小结周围。在常锌常硒组，IgA^＋浆细胞的数量及IgA阳性反应物比较多，而低锌低硒组和高锌高硒组的IgA^＋浆细胞数量及IgA阳性反应物数量减少（P〈0．01），尤其高锌高硒组减少更为明显。结论：低硒低锌或高硒高锌可抑制肉鸡肠道IgA形成，影响肠黏膜的免疫功能。日粮中按50mg／kg锌、0．15mg／kg硒的比例添加，对于维持正常肠道黏膜免疫功能是合适的。     

日粮锌 硒水平对肉鸡小肠黏膜结构的影响

为了探讨微量元素锌和硒互作对肉鸡小肠黏膜结构的影响，将24只1日龄AA肉鸡随机分为3组，分别饲喂添加有高锌高硒(锌1000mg／kg，硒5mg／kg)、低锌低硒(锌34mg／kg，硒0．08mg／kg)和常锌常硒(锌50mg／kg，硒0．15mg／kg)的日粮45d后，观察小肠黏膜的形态结构变化。结果表明，高锌高硒或低锌低硒组肉鸡的小肠黏膜结构有明显的损伤，表现为黏膜厚度和绒毛高度下降，绒毛高度／腺窝深度的比值减少，肠黏膜上皮细胞萎缩。尤其是高锌高硒对空肠的损伤最为严重。而常锌常硒组肉鸡小肠黏膜的形态结构正常。研究结果表明，日粮中按锌50mg／kg和硒0．15mg／kg的比例添加，对于维持小肠黏膜的正常形态结构是合适的；过高或过低的锌和硒对小肠黏膜有毒性作用，且高锌和高硒可相互促进其毒性作用。     

日粮锌硒水平对肉鸡成活率和生产性能的影响

为了研究不同水平的锌、硒对肉鸡成活率和生产性能的影响,试验选择1日龄商品代AA肉仔鸡450羽(公母各半),随机分成9组,分别为1组(低锌低硒)、2组(常锌低硒)、3组(高锌低硒)、4组(低锌常硒)、5组(常锌常硒)、6组(高锌常硒)、7组(低锌高硒)、8组(常锌高硒)和9组(高锌高硒),每组设5个重复,每个重复10羽,试验期6周,测定肉鸡的成活率及增重、料肉比等指标。结果表明:在肉鸡日粮中添加锌50 mg/kg、硒0.15 mg/kg的5组肉鸡的末重、增重、料肉比等生产性能最佳,可提高肉鸡体重,降低料肉比和养鸡成本,增加经济效益,具有加强肉鸡抗病力,增强机体免疫力,降低发病率和死亡率,提高成活率的功效。     

硒锌互作对肉鸡肝脏抗氧化酶活性的影响

选用 2 88只 1日龄健康 AA肉鸡为动物模型 ,随机分成 9组 ,每组 32只 ,动态研究了日粮中不同剂量硒锌互作对肝脏主要抗氧化酶 (CAT、SOD、GSH- Px)活性和脂质过氧化终末代谢产物丙二醛含量的影响 ,探讨了日粮中不同硒锌配比对肝脏抗氧化功能及肝脏功能的影响。饲料中硒、锌各设 3个水平 ,分别为硒 0 .0 8、0 .15、5 m g/ kg和锌 34、5 0、10 0 0 mg/ kg。试验结果表明 ,饲料中低硒 (0 .0 8mg/ kg)、低锌 (34 mg/ kg)、高锌 (10 0 0 m g/ kg)或高硒 (5 mg/ kg) ,尤其是低硒低锌和高硒高锌 ,均可引起肉鸡肝脏 CAT、SOD、GSH- Px3种酶活性下降 ;饲料中加入常硒 (0 .15 mg/ kg)和常锌 (5 0 mg/ kg) ,是肉鸡肝脏抗氧化酶活性维持正常水平的最佳剂量。     

肠粘膜免疫与元素硒关系的研究

实验选用24只1日龄健康xx鸡为动物模型,随机分成3组,每组8只,分别饲喂添加含有不同剂量的硒日粮45天后,观察日粮中不同硒水平互作下鸡肠黏膜结构及黏膜免疫相关细胞的形态、结构、数量和分布的变化,并探讨日粮中不同硒对鸡肠道消化吸收和免疫屏障功能的影响。本实验采用硒的3水平试验设计,各实验组日粮中硒含量分别0.08 mg/kg、0.15 mg/kg、5mg/kg。实验表明:饲料中加入常硒(0.15mg/kg)是维护正常的鸡肠道消化吸收和屏障功能的最佳剂量,而饲料中硒缺乏或过高时,对鸡肠道消化吸收和屏障功能有不同程度的损伤作用,低硒和高硒可加强其毒害作用,使肠道消化吸收和黏膜屏障功能的损伤加重。     

牦牛大肠组织结构及黏膜免疫相关细胞的分布

为了揭示成年牦牛大肠结构和黏膜免疫相关细胞的分布规律,本研究采用光镜及透射电镜等技术,对牦牛盲肠、结肠和直肠组织结构及黏膜免疫相关细胞的分布与数量变化进行研究。结果显示,牦牛大肠壁由黏膜层、黏膜下层、肌层和浆膜构成。大肠黏膜上皮为单层柱状细胞及散在的杯状细胞,在直肠黏膜上皮中则有大量杯状细胞,黏膜上皮纹状缘不明显。固有层内含有大量肠腺和孤立淋巴小结,尤其在盲肠、结肠固有层孤立淋巴小结丰富,且生发中心明显,淋巴小结常伸入黏膜下层。大肠黏膜层平均厚度为(864.18±88.46)μm,其中结肠最厚,盲肠最薄,结肠与盲肠之间差异显著(P<0.01)。肌层分内环与外纵2层,结肠与直肠肌层发达,盲肠肌层最薄,盲肠肌层内环肌形成特殊的肌小结。上皮内淋巴细胞较多,以结肠最丰富,盲肠与结肠差异不明显,从结肠到直肠逐渐减少。盲肠有丰富的浆细胞,从盲肠、结肠至直肠依次减小。肥大细胞在结肠和盲肠均较多,在直肠则显著减少。超微结构显示,大肠黏膜上皮细胞之间有连接复合体,细胞游离面有许多排列整齐的微绒毛。上皮内淋巴细胞胞质少,胞核较大。肥大细胞胞质内有大小不等的高电子密度圆形颗粒聚集。研究表明,牦牛大肠组织结构和其他反刍动物基本相似,但肠壁肌层厚,盲肠有特殊的肌小结,盲肠和结肠黏膜层分布着丰富的孤立淋巴小结和黏膜免疫相关细胞。     

氯化镍对雏鸡盲肠扁桃体影响

本研究采用显微组织学、超微组织学以及末端脱氧核苷酸转移酶介导的dUTP缺口末端标记测定法(TUNEL)等方法,研究了日粮中高水平氯化镍(NiCl_2)对雏鸡盲肠扁桃体的影响。结果表明,NiCl_2处理组与对照组相比,盲肠扁桃体发育受到明显抑制;淋巴滤泡内弥漫排列的淋巴细胞明显减少。超微结构和TUNEL检测发现,900 mg/kg处理组盲肠扁桃体凋亡细胞增多,淋巴细胞线粒体肿胀或空泡化,同时也观察到淋巴细胞核膜扩张。结果表明,日粮中NiCl_2水平超过300 mg/kg时,可抑制盲肠扁桃体的生长,引起组织结构和细胞器的损伤,提示过量NiCl_2可使盲肠扁桃体正常发育和功能受损,从而导致雏鸡消化系统黏膜免疫功能降低。     

高锌日粮对断奶仔猪肠道黏膜免疫及黏膜上皮形态的影响

本试验旨在研究长期饲喂不同锌源的高锌日粮对断奶应激仔猪肠道黏膜免疫及黏膜上皮形态的影响。选用临床检查健康的(26±2)日龄"杜×长×大"三元杂交断奶仔猪60头,按体质量和性别随机分成3组,每组20头,分别饲喂基础日粮、基础日粮+3 000 mg.kg-1氧化锌和基础日粮+500 mg.kg-1蛋氨酸锌。试验期70 d。于试验结束时,每组选取5头仔猪放血致死,分别取十二指肠近端、空肠近端1/4处、空肠远端1/4处和回肠中段,用于测定肠黏膜绒毛高度、绒毛宽度、隐窝深度,小肠上皮间淋巴细胞、杯状细胞数量,粘液层厚度及肠道粘液中IgA的含量。结果显示,在断奶后0～42 d,添加高锌日粮组仔猪的体重和日增重显著或极显著高于对照组仔猪(P0.05或P0.01),而在断奶后42～70 d,对照组仔猪日增重显著高于添加高锌日粮组仔猪(P0.05);两高锌组仔猪小肠黏膜结构有明显的损伤,表现为绒毛高度下降,隐窝变深,肠黏膜上皮细胞萎缩,肠道粘液层厚度变薄;上皮间淋巴细胞数、杯状细胞数和肠道黏液中IgA水平都显著或极显著低于对照组(P0.05或P0.01)。高锌日粮长期暴露引起断奶仔猪锌中毒,改变了肠道黏膜上皮结构的完整性,并降低了仔猪生长性能及肠道黏膜免疫功能。     

山羊咽扁桃体和咽鼓管扁桃体的组织结构观察

选取健康10月龄奶山羊10头,断头宰杀后取咽扁桃体和咽鼓管扁桃体,应用组织学光镜和电镜制片技术研究咽扁桃体和咽鼓管扁桃体的显微和亚显微组织结构.结果表明:山羊咽扁桃体和咽鼓管扁桃体的黏膜上皮主要由2～3层多边形上皮细胞组成,部分区域只有单层扁平细胞,相邻上皮细胞间空隙很大,上皮细胞表面有丰富的微绒毛.上皮细胞之间和黏膜上皮下方固有层内有大量淋巴细胞浸润.扁桃体的实质部分由数个次级淋巴小结和弥散淋巴组织构成,弥散淋巴组织中有大量分布的淋巴管和毛细血管后微静脉.此外,在紧贴黏膜上皮细胞下方的固有层和淋巴滤泡中可观察到少量的树突状细胞.结果提示山羊的咽扁桃体和咽鼓管扁桃体可作为鼻腔免疫的主要诱导位点和效应部位.     

硒和上互作用及对肉用鸡胰腺抗氧化功能的影响

选用健康1日龄AA肉鸡288只，随机分成9组，每组32只，试验观察期为60d；定期剖杀检测，动态观察试验鸡日粮中不同剂量硒与锌对胰腺组织主要抗氧化酶（SOD、GSH－Px及CAT）活性及脂质过氧化终末代谢产物丙二醛（MDA）含量的影响，并探讨了日粮中硒与锌相互作用对胰腺组织结构的影响。结果表明：日粮中低硒（0．08mg/kg)、低锌（34mg/kg)、高硒（5．00mg/kg)、高锌（1000mg/kg)均不同程度地使胰腺抗氧化酶活性下降，组织清除自由基能力减弱，MDA含量增高胰腺的组织结构受到损伤；日粮中添加硒0．15mg/kg、锌50mg/kg能协同提高胰腺SOD、GSH－Px、CAT的活性胰腺组织抗氧化功能，降低胰腺组织中MDA含量能保护胰腺正常组织结构免受过氧化损伤；胰腺MDA含量与SOD、GSH－Px及CAT活性均呈显著负相关，相关系数分别为－0．7046、－0．4200、－0．4263（P＜0．01）。结果显示，胰腺依赖于SOD．GSH－Px及CAT的协同作用以抑制脂质过氧化的进行。     

The effect of selenium and vitamin E on the lymphocytes and immunoglobulin-containing plasma cells in the lymphoid organ and mucosa-associated lymphatic tissues of broiler chickens

The present research has been designed to understand the effect of selenium and vitamin E on the lymphocyte and changes in the frequency of Ig-containing plasma cells in the lymphatic organ and ileum (representative organ for mucosa-associated lymphatic tissues) of different postnatal stages of Kasilla broiler chickens. A routine haematoxylin and eosin (H and E) stain were used to study the histology of the lymphocytic changes, and indirect immunoperoxidase staining method was performed for the study of the distributional and dynamical changes of the Ig-containing plasma cells within the lymphatic tissues and in the ileum of control broilers and in the broilers supplemented with different concentration of selenium and vitamin E in the diet. Histologically, the population of lymphocytes decreased in the lobules of the thymus, medulla of bursal follicles, splenic masses, lymphatic nodules of the cecal tonsil, and villi of the ilium in 0.1 mg and 0.5 mg selenium supplemented broilers in comparison with the control. The population of these cells was found to increase in 150 mg and 300 mg vitamin E supplemented chickens in the present study. In the spleen IgG- and the IgM-containing plasma cells were more than IgA-containing plasma cells. In contrast, in the cecal tonsil and ileum IgA-containing plasma cells were more than IgG- and IgM-containing plasma cells. The frequency of these immunopositive cells were decreased in 0.1 mg and 0.5 mg selenium supplementated chickens, and increased their frequency in the chickens supplemented with 150 mg and 300 mg vitamin E. In the spleen the frequency of IgM-containing plasma cells and both in the cecal tonsil and ileum, the IgG-containing plasma cells were more decreased by selenium supplementation which restored in their population by vitamin E supplementation.     

不同硒源及水平对肉鸡组织硒含量及抗氧化功能的影响

本文旨在研究和比较不同硒源及水平对爱拔益加(AA)肉鸡生长性能、组织硒含量和抗氧化功能的影响,并探讨在生产中应用较低水平(0.20 mg/kg)有机硒替代较高水平(0.30 mg/kg)无机硒的可行性.选用1日龄AA肉仔鸡600只,随机分为5组,分别饲喂基础饲粮(对照组)及在基础饲粮中添加0.30 mg/kg硒(以亚硒酸钠形式)(SS组)、0.20 mg/kg硒(以酵母硒形式)(SY Ⅰ组)、0.30 mg/kg硒(以酵母硒形式)(SYⅡ组)和0.30 mg/kg混合硒(亚硒酸钠和酵母硒形式硒各0.15mg/kg)(MS组)的试验饲粮,每组6个重复,每个重复20只鸡.试验期42 d.结果表明:1)SYⅡ组肉鸡前期平均日采食量显著低于对照组(P＜0.05),饲粮添加各水平有机硒均显著降低了肉鸡全期平均日采食量(P ＜0.05或P＜0.01).2)与对照组和SS组相比,添加各水平有机硒均显著提高了肉鸡胸肌中的硒含量(P＜0.01),且以SYⅡ组最高,显著高于其他各组(P＜0.01);SY Ⅰ组和SYⅡ组肉鸡血浆中的硒含量显著高于对照组(P ＜0.05或P＜0.01);添加各水平有机硒均显著提高了42 d肉鸡肝脏中的硒含量(P ＜0.05或P＜0.01).3)在试验前期(1 ～21 d),较SS组,SYⅡ组肉鸡血浆谷胱甘肽过氧化物酶(GSH-Px)和总超氧化物歧化酶(T-SOD)的活性均显著提高(P＜0.05);较对照组,SS组、SY Ⅰ组和SYⅡ组肉鸡肝脏T-SOD的活性均显著提高(P＜0.05或P＜0.01).在试验后期(22 ～42 d),较对照组,SS组、SY Ⅰ组和SYⅡ组肉鸡血浆和肝脏GSH-Px的活性均显著提高(P＜0.05或P＜0.01),各添加有机硒组肉鸡的血浆丙二醛含量均显著降低(P＜0.05或P＜0.01);与对照组相比,MS组肉鸡肝脏过氧化氢酶(P＜0.05)和GSH-Px的活性均显著提高(P＜0.01).由此可知,饲粮添加0.30 mg/kg酵母硒能够提高肉鸡组织硒沉积量,对其生长性能和抗氧化功能的改善效果最佳;饲粮添加0.20 mg/kg的酵母硒替代0.30 mg/kg亚硒酸钠,在改善肉鸡的生长性能、提高组织硒含量和抗氧化功能方面是可行的.     

Dietary selenium increases vitamin E contents of egg yolk and chicken meat

1. The influence of different forms of dietary selenium (Se) on vitamin E (alpha-tocopherol) and Se contents of egg yolk and chicken meat was investigated. 2. Eggs were collected from laying hens subjected to 4 different dietary treatments after 24 weeks of age. Treatments compared the effects of inorganic Se supplementation (selenite) to those of organic (Se-enriched yeast, Se-enriched alga Chlorella) supplements. In a second experiment the effect of the above organic dietary Se supplementation on the alpha-tocopherol contents of meat from broiler chickens was evaluated. 3. Dietary Se supplementation increased the alpha-tocopherol content of egg yolks from 297 mg/kg dry matter in treatment without supplementation to 311 mg/kg when selenium was supplemented as selenite, and to 370-375 mg/kg when organic supplements were used. The Se and alpha-tocopherol contents of breast and thigh meat in broilers were significantly increased by organic dietary Se supplementation. 4. The inclusion of organic dietary Se sources in the diets of laying hens and broilers would enhance the nutritional value (vitamin E and Se contents) of products (eggs and meat) for human consumption.     

Effect of dietary zinc content and sources on the growth, body zinc deposition and retention, zinc excretion and immune response in chickens.

1. In areas of intensive animal production heavy metals such as zinc (Zn), which is present at high concentrations in poultry excreta in relation to plant requirements, may be at the origin of soil phytotoxicity This study was conducted in order to determine the effect of decreasing dietary Zn content on growth, plasma, tibia and whole body Zn concentrations, immune function, enzyme activity, Zn body retention and Zn concentration in excreta in broilers. 2. Two experiments were carried out using 160 and 80 1-day-old chicks. Broilers received diets with increased Zn contents of 20 to 190 mg/kg. In experiment 1, two sources of zinc methionine were compared to zinc sulphate. 3. A dietary Zn concentration of 45 mg/kg was sufficient to obtain normal broiler performance at 21 d of age. 4. Tibia and plasma Zn concentrations increased linearly with Zn dietary content and reached a plateau at 75 mg/kg, whereas the whole body Zn was saturated when the dietary Zn content was 90 mg/kg. 5. Antibody titres in response to SRBC injection and plasma alkaline phosphatase activity were not affected by dietary zinc concentration. 6. When the dietary Zn content was decreased from 190 to 65 mg/kg, body Zn retention was increased from 8% to 20% and Zn concentration in broiler manure was reduced by 75%. 7. Zn sources had no effect on the parameters measured in this study. 8. A nutritional approach, that is by lowering dietary Zn supplementation may reduce the risks of phytotoxicity in the soil resulting from excessive Zn concentration in manure.     

Effect of different sources and levels of selenium on performance,meat quality,and tissue characteristics of broilers

The objective of this study was to evaluate the effects of dietary levels of inorganic and organic selenium (Se) on performance, meat physicochemical characteristics, and Se deposition in the tissues of broilers chickens. A total of 2,880 one-day-old broilers (Cobb 500 strain) were divided into 96 experimental pens of 30 birds each. The 12 experimental treatments were arranged in a factorial design of 4 × 3 [selenium levels of 0.15, 0.30, 0.45, and 0.60 ppm, and organic (selenium yeast, SY) or inorganic (sodium selenite, SS) sources of selenium and their association (SY + SS)], with 8 replicates in a completely randomized design. No differences (P > 0.05) among Se levels or sources were detected with regard to any performance parameters. The average values of ADFI, ADG, and FCR were 106 g/bird per day, 63 g/bird per day, and 1.684 kg/kg, respectively. No differences (P > 0.05) were found between treatments regarding pH (5.79) and shear force (30.08 kgf). Those birds receiving 0.15 ppm of Se showed a significantly higher (21.92%) cooking loss of breast meat (P < 0.05). The organic form of Se decreased cooking loss, and the smallest loss was found when the diet was supplemented with 0.60 ppm of Se (15.87%). Deposition of Se in the liver increased from 0.97 (0.15 ppm of Se) to 2.43 mg/kg (0.60 ppm of Se) when using SY. The concentration of Se in the breast meat increased linearly from 0.23 to 1.42 mg/kg with increasing dietary levels of SY. Therefore, dietary supplementation with 0.15 ppm of Se, independent of source, can maintain normal bird performance. The SY was more efficient in depositing Se to the liver and breast muscle than the SS.     

Responses of broilers to dietary zinc concentrations and sources in relation to environmental implications

1. Since high concentrations of zinc are associated with reduced crop yields, environmental concerns are emerging regarding zinc accumulation in areas where poultry production is prevalent. This study investigates growth performance and zinc utilisation during the life cycle of broilers when diets were supplemented with various concentrations of zinc from two different sources. 2. A total of 740 Cobb 500 1-d-old male broiler chicks was randomly distributed into 88 battery cages. Excreta were collected over a 48-h period on d 10, 17, 24, 31, 38, and 45 to measure zinc excretion on a dry matter basis. 3. During the 45-d experimental period, broilers were given a maize-soybean meal basal diet (30 mg/kg zinc) supplemented with 0, 20, 40, and 80 mg/kg of zinc from zinc sulphate, Availa Zn amino acid complex, or an equal combination of zinc sulphate and Availa Zn amino acid complex. 4. Progressive additions of zinc to the basal diet significantly increased body weight gain of broilers, but did not affect feed conversion or mortality. Optimum body weight gain was achieved at 80 mg/kg supplemental zinc, which exceeds the NRC recommendations of 40 mg/kg. 5. During each excreta collection period, increased supplemental zinc concentrations significantly increased zinc excretion. However, the zinc source did not influence zinc utilisation. 6. As compared with zinc sulphate supplementation, the cumulative zinc excretion data indicate that adding zinc to the basal diet in the form of Availa Zn amino acid complex decreased zinc excretion.     

烟酰胺与丁酸钠对高密度笼养肉鸡肝脏和肠道氧化应激与炎症反应的影响

为探究烟酰胺和丁酸钠对高密度笼养肉鸡抗氧化和缓解炎症的作用效果,试验采用342只26日龄AA+雄性肉鸡,随机分为5组,每组6个重复。对照组为正常密度组(12.9只/m²)和高密度组(17.1只/m²),试验组为高密度分别饲喂烟酰胺组(50 mg/kg)、丁酸钠(500 mg/kg)、复合添加组(50 mg/kg烟酰胺+500 mg/kg丁酸钠),饲养至46日龄,测定生产性能、血清抗氧化指标、肝脏抗氧化基因mRNA表达和盲肠炎性因子mRNA表达。结果表明:高饲养密度较正常密度组显著降低了肉鸡采食量和体增重,烟酰胺组和复合添加组可缓解高饲养密度造成的生产性能下降的趋势;与正常密度组相比,高密度组显著上调了肝脏中血红素加氧酶(HO-1)、核因子E2相关因子2(Nrf2)、盲肠扁桃体白介素6(IL6)、白介素10(IL10)mRNA的表达;与高密度组相比,复合添加烟酰胺和丁酸钠显著上调了肝脏谷胱甘肽过氧化物酶(GSH-Px)、HO-1、肿瘤坏死因子α(TNF-α)和Nrf2的mRNA表达量,显著下调盲肠扁桃体IL6、IL10基因mRNA的表达量。综上可知,在高密度笼养条件下,家禽饲粮中复合添加烟酰胺和丁酸钠可以提高肉鸡的生产性能,缓解高密度氧化应激导致的肉鸡炎症基因表达,Keap1-Nrf2-ARE信号通路可能参与了烟酰胺和丁酸钠对肉鸡抗氧化能力的调控。     

Dietary vitamin E (alpha-tocopherol acetate) and selenium supplementation from different sources: performance, ascites-related variables and antioxidant status in broilers reared at low and optimum temperatures

1. This study compared the effect of dietary supplementation with organic or inorganic selenium (Se) sources plus control amounts or large amounts of vitamin E (alpha-tocopherol acetate) in broilers raised at control (20 to 24 degrees C) or low (14.5 to 16.8 degrees C) temperatures after 2 weeks of age. 2. The following dietary treatments were used from one day old. Diet 1, the control diet, comprised a commercial diet containing 0.15 mg/kg inorganic Se and 50 mg vitamin E/kg feed. Diet 2 was the same as diet 1, supplemented with 0.15 mg/kg inorganic Se. Diet 3 was the same as diet 2 but was supplemented with 200 mg/kg vitamin E. Diet 4 was the same as diet 1, but inorganic Se was replaced with 0.30 mg/kg organic Se. Diet 5 was the same as diet 4, supplemented with 200 mg/kg vitamin E. 3. Low temperature reduced the growth rate of broilers; however, at 6 weeks, there were no differences in the body weights of birds fed on organic Se supplemented diets housed at low or control temperature. The feed conversion ratio was significantly affected by low temperature but not by diet. The heterophil/lymphocyte ratio was higher in chicks after one week in the cold, indicating mild stress. Blood triiodothyronine levels were significantly higher in birds after 1 and 4 weeks in the cold but thyroxin was not affected. 4. Organic Se supplementation increased relative lung weight at the control temperature, which might lead to greater respiratory capacity. Relative spleen weight significantly decreased in broilers fed diets supplemented with inorganic Se under cold conditions, a possible indication of chronic oxidative stress. 5. At the low temperature, supplementation with organic Se alone, or with inorganic Se and vitamin E increased glutathione peroxidase (GSHPx) activity and glutathione (GSH) concentration in the liver of broilers, which may indicate increased activity of birds' antioxidant defence against suboptimal environments.     

Nano-sized Zinc in Broiler Chickens: Effects on Growth Performance,Zinc Concentration in Organs,and Intestinal Morphology

The effects of dietary supplementation of zinc (Zn) sources and concentrations were investigated on growth performance, absorption into tissues, fecal excretion, nutrient retention, and intestinal morphology in broilers fed a corn-soybean meal basal diet. A total of 525 one-day-old chicks (Ross 308) were assigned based on body weight to seven dietary treatments. There were five replicate pens for each treatment and 15 broilers per replicate pen. The dietary treatments included a basal diet (control, without supplementing Zn), and basal diet supplemented with Zn, as inorganic zinc sulfate (ZnS; 110 mg/kg); organic Zn-methionine (ZnM; 110 mg/kg); hot-melt extruded (HME) 25 zinc sulfate (27.5 mg/kg); HME50 zinc sulfate (55 mg/kg); HME75 zinc sulfate (82.5 mg/kg); or HME100 zinc sulfate (110 mg/kg) for 35 days in two phases (d 1–21, phase I and d 22–35, phase II). Bodyweight and feed efficiency of broiler chicks fed diets supplemented with increasing dietary concentrations of HME-Zn improved linearly during the study period (P<0.05). Compared to the control treatment, the ZnS, ZnM, and HME diets increased Zn concentrations in the serum and liver. Inorganic ZnS supply resulted in the highest Zn concentration in excreta. Increasing supplemented Zn content in diets as HME linearly increased Zn concentration in the excreta, serum, liver, and tibia. Broiler chicks fed diets supplemented with increasing concentrations of HME increased villus height (VH; linear and quadratic) of the jejunum and VH of the ileum (linear). Increasing concentrations of dietary Zn supplied as HME resulted in linearly enhanced dry matter, gross energy, and nitrogen retention of broilers on day 21. These results suggest that dietary HME-Zn at a lower level (55 ppm) shows the same growth performance as common ZnSO₄ at 110 ppm.