The effect of selenium deficiency in goats on lymphocyte production of leukocyte migration inhibitory factor

The effect of dietary selenium on caprine leukocyte migration inhibitory factor (LMIF) production was examined $\text{in vitro}$ using lymphocytes from goats fed a diet deficient in selenium. Selenium deficiency was determined by decreased plasma glutathione peroxidase (GSH-Px). The ability of peripheral blood lymphocytes to produce LMIF induced by concanavalin A (Con A) was significantly (P < 0.05) inhibited when cells from selenium-deficient and selenium-adequate goats were compared. In contrast, no significant (P > 0.05) differences were found between lymphocytes from selenium-deficient and selenium-adequate goats for Interleukin-2 (IL-2) production and blastogenesis induced by Con A. These data suggest that selenium deficiency may selectively impair LMIF production and hence the ability of lymphocytes to modulate neutrophil migration.     

Effect of Rhodococcus equi on equine polymorphonuclear leukocyte function

A procedure was developed for isolating large numbers of purified polymorphonuclear leukocytes (PMNs) from the peripheral blood of horses. Equine PMN function was evaluated by three procedures: 1) Staphylococcus aureus ingestion, 2) nitroblue tetrazolium reduction, and 3) iodination. Four preparations of R. equi were added to polymorphonuclear leukocytes (PMNs) in each test system. Live bacteria, heat-killed bacteria, the washed pellet from heat-killed bacteria, and the supernatant fluid from heat-killed bacteria were evaluated for effects on equine PMN function. None of the R. equi preparations had an effect on S. aureus ingestion by equine PMNs. Nitroblue tetrazolium reduction by PMNs, a measure of oxidative metabolism, was suppressed by pellet and supernatant fractions. Values for the iodination reaction were depressed by all R. equi preparations, indicating decreased activity of the myeloperoxidase-H2O2-halide system of the PMN. Further evaluation of the supernatant from heat-killed R. equi showed that it retained its inhibitory effect on iodination following autoclaving and/or passage through a 10,000 MW filter. R. equi fractions did not alter the enzymatic conversion of 125I to a protein-bound form in a PMN-free assay developed to evaluate this reaction. The presence of a surface component capable of inhibiting bactericidal mechanisms of the PMN may play an important role in intracellular survival of R. equi.     

硒、维生素B_2对蛋鸡产蛋性能及鸡蛋中硒、维生素B_2含量的影响

选择健康350日龄海蓝灰商品蛋鸡96只,采用2×3因子随机设计进行试验,随机分为6个处理,每个处理组4个重复,每个重复4只鸡,分别在饲粮中添加10.8、14.4mg/kg的维生素B2(80%)和0.2、0.4、0.6mg/kg的硒,观察维生素B2和硒对蛋鸡产蛋率、蛋重、鸡蛋中维生素B2和硒含量的影响。结果表明:①日粮中添加不同水平硒、维生素B2复合,对蛋鸡产蛋性能影响差异不显著(P0.05);②在日粮中添加高浓度维生素B2,鸡蛋中维生素B2含量逐渐增加,差异显著(P0.05),对鸡蛋中维生素B2含量变化,硒和维生素B2之间没有协同作用;③随日粮中硒添加量的增加,硒在鸡蛋中沉积显著增加,在18d左右达到高峰,添加0.4、0.6mg/kg硒组比0.2mg/kg组分别提高了73.3%和97.8%。     

Effect of antimicrobial agents and corticosteroids on bovine polymorphonuclear leukocyte chemotaxis

The effect of certain antimicrobial agents and corticosteroids on bovine polymorphonuclear leukocyte chemotaxis was investigated. Peripheral blood was fractioned by density-gradient centrifugation, using Ficoll-Hypaque. The chemotactic assay was performed in modified Boyden chambers, using Micropore filters, and the chemotactic response was measured by the leading-front technique. Tetracyclines, streptomycin, and penicillin had no effect on chemotaxis at concentrations normally achieved in blood during systemic treatment. However, higher concentrations that were achievable with local therapy, such as intramammary injection or topical application, inhibited the chemotactic response. This inhibition was eliminated by serum. Dexamethasone stimulated polymorphonuclear leukocyte chemotaxis with the effect being manifested after the cells were incubated with the drug for 3 hours. Hydrocortisone caused slight inhibition of chemotaxis, whereas prednisone and prednisolone had no effect.     

Bovine leukocyte adhesion deficiency: in vitro assessment of neutrophil function and leukocyte integrin expression.

Bovine leukocyte adhesion deficiency (BLAD) was identified in a two-month-old Holstein heifer calf using DNA-polymerase chain reaction analysis of the affected calf and other clinical parameters. Neutrophil integrin expression (CD18, CD11a, CD11c), aggregation, and transendothelial migration were studied in vitro. Neutrophils were isolated from the affected calf and from normal, healthy, age-matched control Holstein calves. Neutrophils isolated from the affected BLAD calf had decreased expression of leukocyte integrins on their cell surface, decreased ability to aggregate in response to chemotactic stimuli, and decreased ability to migrate across bovine endothelial cell monolayers in vitro. Transendothelial migration of neutrophils from normal calves was reduced to levels comparable to the BLAD neutrophils by treatment with an anti-CD18 monoclonal antibody (MAb 60.3). Peripheral-blood lymphocytes from the BLAD calf also expressed negligible levels of leukocyte integrins, similar to their neutrophil counterparts. Our experimental findings in vitro correlate well with the clinical observations of decreased leukocyte trafficking and diminished host defense in leukocyte adhesion-deficient animals. The syndrome of BLAD may be a suitable model for one of the human leukocyte adhesion deficiency disorders.     

硒、维生素B_2复合对不同日龄蛋鸡产蛋性能及鸡蛋中硒、维生素B_2含量影响

试验在饲料中复合添加硒、维生素B2,以144、470、640日龄的产蛋鸡为试验动物,研究日粮中添加14.4 mg/kgVB2(80%)、0.4 mg/kg的亚硒酸钠对不同日龄蛋鸡的产蛋性能及鸡蛋中硒、维生素B2含量的影响。试验选取144、470、640三种日龄的海蓝灰蛋鸡各32只,设对照组、试验组两个处理;每个处理各4个重复,每个重复4只鸡。试验结果表明:①各日龄的蛋鸡试验组与对照组相比在各种生产性能,蛋重、产蛋率、日采食量等有增加趋势,但差异不显著(P>0.05);②同一日龄的蛋鸡试验组鸡蛋中硒、维生素B2含量高于对照组鸡蛋中硒、维生素B2含量,差异显著(P<0.05);③日粮中复合添加硒、维生素B2对不同日龄的蛋鸡鸡蛋中硒、维生素B2增加量无显著性差异,未见规律性变化。     

Assessment of leukotriene B4 production in leukocytes from horses with recurrent airway obstruction

OBJECTIVE: To determine the ex vivo leukotriene (LT) biosynthesis in peripheral blood neutrophils (PBNs) and inflammatory cells in bronchoalveolar lavage fluid (BALF) obtained from horses affected with recurrent airway obstruction (RAO). ANIMALS: 6 RAO-affected and 6 control horses. PROCEDURES: Before and 6, 24, and 48 hours after stabling, disease severity was determined subjectively by clinical and mucus scores and measurement of the maximal change in pleural pressure (deltaPpl(max)); PBNs were isolated and BALF samples were examined cytologically. The PBN and BALF cells were activated with a calcium ionophore in the presence of arachidonic acid, and production of LTC4 and LTB4 was measured per 10(6) cells. RESULTS: Clinical and mucus scores and deltaPpl(max) increased during stabling in RAO-affected horses, but not in control horses. In neutrophils and BALF cells from both groups, production of LTB4 exceeded that of LTC4. At all times, LTB4 production by PBNs was less in RAO-affected horses than it was in control horses. Before stabling, LTB4 production by cells in BALF was low in RAO-affected horses, but increased considerably after 6 hours of stabling. This increase coincided with the migration of neutrophils into the airways. In control horses, production of LTB4 did not change during stabling. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested increased production of LTB4 in airways of RAO-affected horses, compared with control horses, that may contribute to the infiltration of neutrophils into the lungs and the sustained inflammation associated with RAO.     

Effect of antibiotics and vehicles on bovine mammary polymorphonuclear leukocyte morphologic features, viability, and phagocytic activity in vitro

Effects of antibiotics and antibiotic vehicles on polymorphonuclear leukocytes (PMNL) isolated from bovine mammary glands were studied in vitro. Amikacin, dicloxacillin, erythromycin, gentamicin, lincomycin, nitrofurantoin, novobiocin-penicillin, polymyxin B, rifampin, tetracycline, or tiamulin was added to culture medium at 1 mg/ml and chloramphenicol was added at 4 mg/ml. Drug concentrations were equivalent to those detected in milk immediately after injection into the mammary gland. Vehicles included mineral oil and peanut oil, each at a dilution of 1:100 in culture medium. The PMNL morphologic features, viability, and phagocytic activity were evaluated. In comparison with the phosphate-buffered saline solution (PBSS) control, significant (P less than 0.05) alterations in normal cell morphologic features were observed in PMNL cultured with tetracycline, nitrofurantoin, erythromycin, polymyxin B, rifampin, novobiocin-penicillin, chloramphenicol, tiamulin, or peanut oil. Viabilities of PMNL cultured with chloramphenicol, novobiocin-penicillin, or tiamulin were significantly (P less than 0.05) reduced when compared with those of PBSS controls. Addition of Staphylococcus aureus to culture medium enhanced morphologic alterations and reduced viabilities of PMNL. Phagocytosis of S aureus by PMNL was significantly (P less than 0.05) depressed in medium containing novobiocin-penicillin, amikacin, rifampin, chloramphenicol, tiamulin, or peanut oil in comparison with that of PMNL incubated in PBSS.     

Lipopolysaccharide and cytokines modulate leukotriene (LT)B4 and LTC4 production by porcine endometrial endothelial cells

Uterine inflammatory response is mediated by inflammatory mediators including eicosanoids and cytokines produced by immune and endometrial cells. Interactions between lipopolysaccharide (LPS) and cytokines, and leukotrienes (LTs) in endothelium, important for the host defence during the inflammation, are unknown. We studied the effect of LPS, tumour necrosis factor (TNF)‐α, interleukin (IL)‐1β, IL‐4 and IL‐10 on 5‐lipooxygenase (5‐LO), LTA₄ hydrolase (LTAH) and LTC₄ synthase (LTCS) mRNA and protein expression, LTB₄ and LTC₄ release from porcine endometrial endothelial cells, and cell viability. For 24 hr, cells were exposed to LPS (10 or 100 ng/ml of medium) and cytokines (each 1 or 10 ng/ml). 5‐LO mRNA/protein expression augmented after incubation with larger doses of LPS, TNF‐α, IL‐4 and IL‐10 and smaller dose of IL‐1β. Larger dose of TNF‐α, smaller doses of LPS and IL‐1β and both doses of IL‐10 increased LTAH mRNA/protein expression. LTAH protein content was up‐regulated by larger dose of LPS, but it was reduced in response to both doses of IL‐4. LTCS mRNA expression was elevated by larger doses of LPS, IL‐4 and IL‐10 or both doses of TNF‐α and IL‐1β. LTCS protein level increased after treatment with both doses of IL‐1β, IL‐4 and IL‐10, smaller dose of LPS and larger dose of TNF‐α. Both doses of LPS and larger doses of TNF‐α and IL‐10 increased LTB₄ release. LPS, IL‐1β and IL‐10 at smaller doses, or TNF‐α and IL‐4 at larger doses stimulated LTC₄ release. Smaller doses of TNF‐α and IL‐1β or both doses of IL‐4 enhanced the cell viability. This work provides new insight on the participation of LPS, TNF‐α, IL‐1β, IL‐4 and IL‐10 in LTB₄ and LTC₄ production/release from porcine endometrial endothelial cells, and the effect of above factors on these cells viability. The used cellular model gives the possibility to further establish the interactions between inflammatory mediators.     

Studies on vitamin E and selenium deficiency in young pigs. III. Effect on kinetics of erythrocyte production and destruction.

The effect of vitamin E and/or selenium deficiency on the kinetics of erythrocyte production and destruction has been investigated in swine. The plasma iron turnover rate, 59Fe incorporation into newly formed red cells as well as the 51Cr apparent red cell half-life, were not found to be significantly affected by either vitamin E deficiency, selenium deficiency or deficiency of both, as compared to replete animals. The results of this study suggest that vitamin E is not a limiting factor for normal erythropoiesis in young growing pigs. Erythropoiesis appeared, however, to be slightly decreased in selenium deficient pigs and will need to be further investigated.     

Effect of selenium on performance, serum selenium concentration and glutathione peroxidase activity in pigs

Pigs from sows fed a diet deficient in Se and low in vitamin E were fed a Torula yeast diet supplemented with 100 IU dl-alpha-tocopheryl acetate/kg of diet. Dietary treatments were levels of supplemental Se of 0, .025, .050, .075 or .100 ppm. Some death loss occurred in pigs receiving no supplemental Se at approximately 5 wk of age. Autopsy revealed liver and heart lesions typical of vitamin E-Se deficiency. Selenium supplement had no significant effect on average daily gain, feed intake or gain to feed ratio for the 4-wk experiment. Selenium status of pigs was determined by serum Se concentration and serum glutathione peroxidase (GSH-Px) activity. Serum Se increased linearly (P less than .01) with increasing supplemental Se. Serum GSH-Px activity increased linearly (P less than .01) and quadratically (P less than .05) with increasing supplemental Se. With time, the level of serum Se and GSH-Px activity decreased in unsupplemental pigs, but increased in pigs fed diets supplemented with Se and resulted in significant interactions (P less than .01) between dietary Se level and time on experiment. The correlation between serum Se concentration and GSH-Px activity was .81 (P less than .01).     

Influence of chemotactic agents on the locomotion of equine polymorphonuclear and mononuclear leucocytes

Subpopulations of equine leucocytes, polymorphonuclear and mononuclear cells, were separated from whole blood on a discontinuous Percoll gradient and used in studies of chemokinesis and chemotaxis. Polymorphonuclear cells responded to the chemo-attractant properties of zymosan-activated plasma in Boyden chamber and agarose microdroplet assays but they responded only slightly (Boyden chamber) or not at all (agarose microdroplet) to the peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP). Equine mononuclear cell movement was increased by FMLP in both assay systems and these cells also responded to zymosan activated plasma in the Boyden chamber assay but not in the agarose microdroplet. It is concluded that factors controlling equine polymorphonuclear and mononuclear cell movements into inflammatory exudates may differ.     

Effects of ACTH administration on bovine polymorphonuclear leukocyte function and lymphocyte blastogenesis

Yearling steers were treated with ACTH to determine the effect of increased plasma cortisol concentration on bovine lymphocyte and polymorphonuclear leukocyte (PMN) function. The administration of ACTH caused a significant (P less than 0.01) increase in serum cortisol concentration and depression of lymphocyte blastogenesis in response to phytohemagglutinin and concanavalin A. The response to pokeweed mitogen was also depressed, but not significantly. Random migration by PMN was significantly enhanced by ACTH treatment, but there was no effect on ingestion of Staphylococcus aureus, nitroblue tetrazolium reduction, or antibody-dependent cell-mediated cytotoxicity by PMN. The iodination reaction, which evaluates the activity of the myeloperoxidase-hydrogen peroxide-halide antibacterial system of the PMN, was significantly impaired after ACTH treatment. These data indicate that specific parameters of lymphocyte and neutrophil function were impaired directly or indirectly by elevated in vivo concentrations of plasma cortisol.     

仔猪氧化应激及硒的抗氧化效应与机制

氧化应激（Oxidative Stress）是机体应答内外环境，通过氧化还原反应对机体进行多层次应激性调节和信号转导，同时造成氧化损伤的重要生命过程。在正常生理条件下，机体的调节机制会使体内处于相对自稳态，此时尽管也有自由基的产生，但会受到抗氧化体系的淬灭，从而维持在正常生理范围内。当动物遭受应激刺激或患病时，机体代谢出现异常而骤然产生大量自由基，     

硒的抗氧化功能及在动物生产中的应用

本文对硒的理化性质、生物活性及其抗氧化功能的机理进行综述,并探讨了不同硒源对动物抗氧化机能的影响及在生产上的应用。     

Effect of different selenium sources on production performance and biochemical parameters of broilers

Selenium (Se) is an essential trace element for animal and human. Supplementation of Se usually in livestock diet has been proved as effective element. This study was conducted to investigate the effect of different sources of selenium on growth performance, slaughter performance, immune trait, oxidation resistance, meat quality and selenium content in tissue of broilers to comprehensively evaluate the effect of selenium. A total of 324 1‐day‐old AA broilers were selected and randomly allocated to three treatments of six replicates with 18 broilers each. The trial period was 42 days and was divided into two periods. Our results showed that effect of different sources of selenium on growth performance, slaughter performance, the immune status, drip loss and flesh had not significant difference (p > 0.05); while the activities of serum glutathione peroxidase (GSH‐Px), total superoxide dismutase (T‐SOD), the abilities to inhibit hydroxyl radical (OH˙) and total antioxidant capacity (T‐AOC) were significantly higher in selenium yeast than sodium selenite groups, and the contents of MDA of selenium yeast groups were significantly lower than that of sodium selenite. This study demonstrated that the different sources of selenium had no obvious effect on production performance of broilers, but significantly influenced the broiler oxidation resistance.     

Effects of dietary supplementation of Chinese medicinal herbs on polymorphonuclear neutrophil immune activity and small intestinal morphology in weanling pigs

The purpose of this study was to evaluate the effects of dietary Chinese medicinal herbs (CMH) supplementation composed of Panax ginseng, Dioscoreaceae opposite, Atractylodes macrocephala, Glycyrrhiza uralensis, Ziziphus jujube and Platycodon grandiflorum, on the performance, intestinal tract morphology and immune activity in weanling pigs. Two hundred and forty weaned pigs were assigned randomly to four dietary groups including the negative control (basal diet), 0.1% CMH, 0.3% CMH and 0.114% antibiotic (Chlortetracycline calcium Complex, Sulfathiazole and Procaine Penicillin G) supplementation groups for a 28-day feeding trial. Results indicated that both CMH supplementation groups had a better gain and feed/gain than control group (CT) during the first 2 weeks of the experimental period. The 0.3% CMH had a significant decrease in the diarrhoea score in first 10 days of experimental period when compared with other groups. The CMH supplementation groups had a higher villous height, increased lactobacilli counts in digesta of ileum and decreased coliform counts in colon compared with CT. The immune activities of polymorphonuclear leucocytes (PMNs), including the respiratory burst and Salmonella-killing ability, were significantly enhanced in CMH supplementation groups at day 7 of experiment period. The CMH and antibiotic supplementations increased the nutrient digestibility such as dietary dry matter, crude protein and gross energy in weanling pigs. In conclusion, the dietary CMH supplementation improved intestinal morphology and immune activities of PMNs, thus giving rise to nutrient digestibility and reduce diarrhoea frequency in weanling pigs.     

Effect of intramammary infusion of rbGM-CSF on SCC and expression of polymorphonuclear neutrophil adhesion molecules in subclinical mastitis cows

The effect of rbGM-CSF intramammary infusion on the subclinical mastitis was evaluated by the somatic cell count (SCC) and expression of adhesion molecules (CD62L and CD11b) on the surface of neutrophils (PMN) in blood and milk. Fifteen cows diagnosed to have subclinical mastitis were used in this study. Seven cows showed a decrease in the SCC (decreased group), whereas 8 cows showed an increase in the SCC (increased group) 7 days after infusion of rbGM-CSF compared to pre infusion level. The percentage of CD62+ cells tended to be lower and CD11b+cells tended to be higher at 6 h on blood PMN in the decreased group of cows. Increased group of cows showed opposite tendencies. The mean fluorescent intensity of these adhesion molecules expressed on PMN in blood and milk was similar in both groups. These results suggested some association between expression of adhesion molecules and changes in SCC by rbGM-CSF. Responsiveness of PMN adhesion molecules to rbGM-CSF might determine the changes in SCC of the subclinical mastitic cows after infusion of rbGM-CSF.