欧亚鲈幼鱼饲料中维生素C适宜含量的研究

选用初始体质量为(7.46±0.29)g的欧亚鲈幼鱼为试验对象,投喂6种不同水平的维生素C(0、50、100、200、400和800 mg/kg)的试验饲料,饲养8周,探讨欧亚鲈幼鱼饲料维生素C的适宜含量。结果表明,饲料中维生素C添加量从0.0升高到100 mg/kg时,鱼体增重率呈上升趋势,添加量为100 mg/kg显著高于对照组(P<0.05),但添加量继续增大,对鱼体增重率无显著变化(P>0.05);经折线模型分析表明,欧亚鲈鱼种达到最大生长时,饲料中的维生素C的最低添加量为93.58 mg/kg。欧亚鲈肝脏中维生素C含量随着饲料中维生素C(0～200 mg/kg)的增加而显著升高(P<0.05),但添加量继续升高,则肝脏中维生素C达到饱和状态,经折线分析表明,肝脏中维生素C达到饱和时,饲料中的维生素C的最低添加量为149.27 mg/kg。急性胁迫前,各组血糖之间无显著差异(P>0.05),急性胁迫后,血糖升高峰值最低和恢复最快的是饲料中维生素C为400～800 mg/kg。在本试验条件下,欧亚鲈幼鱼达到最大生长、肝脏维生素C饱和及抗拥挤胁迫的维生素C适宜添加量分别为93.58、149.27 mg/kg和400 mg/kg。     

Alterations on vitamin C synthesis and transportation and egg deposition induced by dietary vitamin C supplementation in Hy-Line Brown layer model

In ovo feeding of vitamin C (VC) has positive effects on the growth performance, immune and antioxidant function in poultry, which indicates that increasing VC content in eggs may be of benefit. This study was to investigate the effects of dietary VC supplementation on VC synthesis and transportation and egg deposition. In Exp. 1, in order to select a suitable animal model, VC content was detected in different eggs from different layer species. Vitamin C content was lower in ISA Brown breeder eggs and Hy-Line Brown layer eggs (P < 0.05) then in Arbor Acres breeder eggs. In Exp. 2, a total of 24 Hy-Line Brown layers (42-week-old) were randomly divided into 3 treatments with 8 replicates and fed a basal diet with VC at 0, 200 and 400 mg/kg. Sodium-dependent VC transporter 1 and 2 (SVCT1 and SVCT2) expressions were higher in ileum than in duodenum and jejunum (P < 0.05). SVCT1 expression was higher but SVCT2 expression was lower in the magnum than in the ovary (P < 0.05). L-Gulonolactone oxidase (GLO) and SVCT1 expressions were higher but SVCT2 was lower in the kidney than in the liver (P < 0.05). Dietary VC supplementation at 400 mg/kg increased SVCT1 expression in duodenum, ovary and magnum, but decreased GLO and SVCT1 expression in liver (P < 0.05). Dietary VC supplementation at 200 and 400 mg/kg increased SVCT2 expression in duodenum, but decreased GLO and SVCT1 expression in kidney and SVCT2 expression in liver (P < 0.05). Dietary VC supplementation promoted VC absorption in duodenum and jejunum, but reduced endogenous VC synthesis in liver and kidney. Although dietary VC supplementation enhanced VC transportation in ovary and magnum, it did not increase VC deposition in produced eggs.     

Vitamin C supplementation has no effect on American bullfrog's immune response

American bullfrog (Lithobates catesbeianus) is the only species raised in Brazilian commercial frog farms, and the intensive culture of these animals has gained great popularity in Brazil over the past several years. Stress is one of the major obstacles in frog culture. To minimise this problem, the aim of the present study was to investigate the role of added vitamin C in the diet of American bullfrogs as an antistress factor through the assessment of plasma corticosterone, leucocyte levels and macrophage activation in animals raised in confinement. The experimental design was entirely randomised, with six treatments (supplementation of 0, 250, 500, 750, 1000 and 2000 mg of vitamin C/kg of feed) and four replications. The plasma corticosterone level, leucocyte level and macrophage activation were evaluated. It was concluded that vitamin C had no influence on the evaluated parameters due to the possible adaptation of the animals to life in captivity (domestication). The results of this research indicate that farmers should not increase the levels of vitamin C in commercial feeds because this would only enhance production costs.     

Effects of vitamin C supplementation on growth performance and antioxidant status of layer ducklings

The study was conducted to evaluate the effects of increasing dietary vitamin C supplements on growth performance, antioxidant status and humoral immunity of layer ducklings. The results showed that the body weight and daily body weight gain of ducklings increased (p < 0.05) with increasing dietary vitamin C supplementations and reached a maximum at 400 mg vitamin C/kg feed. The dietary vitamin C supplementations reduced the malondialdehyde concentration (p < 0.05) and increased the activities of superoxide dismutase and glutathione peroxidase (p < 0.05) in serum and liver of ducklings at day 5 and 28. Additionally, feeding 400 mg/kg or 800 mg vitamin C/kg feed increased IgM and IgA concentrations in sera (p < 0.05) and serum IgG concentrations increased (p < 0.05) following supplementation in concentrations of 150-800 mg vitamin C/kg feed. In conclusion, the results suggested that dietary vitamin C supplements of 400 mg/kg feed provide optimal effects on growth performance, antioxidant status and parameters of humoral immunity.     

Effects of dietary vitamin E and fat supplementation in growing-finishing swine fed to a heavy slaughter weight of 150 kg: II. Tissue fatty acid profile,vitamin E concentrations,and antioxidant capacity of plasma and tissue

The study aimed to assess the effects of vitamin E (VE) supplementation and fat source on fatty acid (FA) composition, VE concentrations, and antioxidant capacity in plasma and tissues of pigs fed to a heavy slaughter weight (150 kg). A total of 64 pigs (32 barrows, 32 gilts; 28.41 ± 0.83 kg) were blocked by sex and weight, and randomly assigned to one of eight dietary treatments (n = 8 per treatment) in a 4 × 2 factorial arrangement. Fat sources included corn starch (CS), 5% tallow (TW), 5% distiller’s corn oil (DCO), and 5% coconut oil (CN); VE supplementation levels were 11 and 200 ppm. Five-phase diets were formulated to meet requirement estimates of NRC (2012) and fed to pigs for each period of 25 kg from 25 to 150 kg. Increasing VE supplementation level increased C16:1 (P < 0.05) content but decreased C20:0 (P < 0.05) content in backfat and belly fat, while in liver, it increased C17:0 (P < 0.05) but decreased C18:0 (P < 0.05). Compared to the pigs fed the CS diet, the pigs fed the CN diet had greater (P < 0.05) content of total saturated FA, the pigs fed the DCO diet had greater (P < 0.05) content of total polyunsaturated FA content and iodine value, and the pigs fed the TW diet had greater (P < 0.05) content of total monounsaturated FA in backfat, belly fat, and liver. Plasma VE concentrations increased linearly (P < 0.05) with increasing length of feeding but faster (P < 0.05) in the pigs fed the CN and TW diets compared with the CS and DCO diets within the 200 ppm VE level; the pigs fed the DCO diet had the highest plasma VE concentrations (P < 0.05) from Phase 2 to Phase 5 within the 11 ppm VE level. The VE concentrations in liver and loin muscle (P < 0.05) increased with increasing dietary VE level from 11 to 200 ppm, but it was not affected by dietary fat source. There was no effect of VE supplementation and fat source on antioxidant capacity in plasma and liver except that pigs fed the DCO diet had greater liver SOD activity (P < 0.05) than the pigs fed the CN diet. In conclusion, dietary VE supplementation did not affect FA profile in backfat, belly fat, and liver consistently, while dietary FA composition with different fat sources affected much of the FA profile in backfat, belly fat, and liver. The higher level of VE supplementation increased liver and muscle VE concentrations and dietary fat sources affected plasma VE concentrations differently (P < 0.05), wherein the TW and CN diets increased the VE absorption greater than the DCO diet.     

L-Ascorbic acid (vitamin C) supplementation to optimize health and reproduction in cattle

Cattle can synthesize L-ascorbic acid (or Vitamin C) from either D-glucose or D-galactose through glucuronic acid pathway in the liver. L-Ascorbic acid present in cattle diet is almost totally destroyed by rumen microorganisms making them essentially dependent on its endogenous synthesis, which is assumed sufficient to meet the physiological requirement. Therefore, the role of vitamin C in cattle health and disease has remained widely overlooked. However, there is mounting evidence that the level of L-ascorbic acid in blood and other tissues decreases in association with stress and disease, and Vitamin C supplementation revealed favorable response as evident from early recovery. The present review is an attempt to summarize the existing literature pertaining to the physiological role of L-ascorbic acid and the scope of its supplementation in the prevention and treatment of diseases in cattle. It should be realized that the aqueous solution of vitamin C is highly acidic and subcutaneous or intramuscular administration may cause tissue irritation and inflammation, whereas the sodium ascorbate solution is less acidic and might be used for intramuscular administration.     

锌和维生素C对热应激条件下肉鸡生长性能和免疫反应的影响

文章旨在研究日粮单独或联合使用锌和维生素C对高温条件下肉鸡生长性能和免疫反应的影响。试验选择320只1d肉仔鸡,根据体重随机分为4组,每组4个重复,每个重复20只鸡。对照组饲喂基础日粮(锌含量为40mg/kg),处理1组在基础日粮中添加60mg/kg锌,处理2组在基础日粮中添加200mg维生素C,处理3组在基础日粮中添加60mg/kg锌+300mg/kg维生素C,试验共开展35d。在试验第21~35天对鸡只进行热应激诱导,即25℃12h,25~34℃3h,34℃6h,34~25℃3h。结果显示:处理组较对照组均显著提高了肉鸡的采食量、体增重(P<0.05),显著降低了料比(P<0.05)。日粮同时添加锌和维生素C组肉鸡采食量和体增重最高(P<0.05)。与对照组相比,日粮添加60mg/kg锌、200mg/kg维生素C或锌和维生素C联合使用的肉鸡脾脏、胸腺和法氏囊重量显著提高(P<0.05)。60mg/kg锌+200mg/kg维生素C和200mg/kg维生素C组较对照组显著提高了新城疫、传染性法氏囊炎和传染性支气管炎的抗体滴度(P<0.05)。与对照组相比,60mg/kg锌+200mg/kg维生素C、200mg/kg维生素C组和60mg/kg锌组显著提高了血液白细胞总数、淋巴细胞和单核细胞占比(P<0.05)。结论:在本试验条件下,日粮单独或联合添加锌和维生素C均可显著改善热应激条件下肉鸡的生长性能和免疫状态。     

维生素C、E及其交互作用对肉仔鸡生长性能及鸡肉品质的影响

本试验旨在研究维生素C、E(VC、VE)及其交互作用对肉仔鸡生长及其鸡肉品质的影响。试验采用4×4完全随机试验设计将800只1日龄健康的艾维茵肉仔鸡随机分成16个处理,每个处理5个重复,每个重复10只。其中,VE设4个添加水平,分别为50、100、200、400 mg/kg日粮,VC的添加水平为50、100、200、400 mg/kg日粮。结果表明:在生长前期(0～21 d),日粮VE、VC的添加量对肉仔鸡日增重均无显著影响(P>0.05),VE、VC的互作效应在生长前期对肉仔鸡日增重和料重比的影响均不显著(P>0.05),前期VE(200 mg/kg)×VC(50 mg/kg)组料重比最低;在生长后期(4～6周龄),日粮VE、VC的添加量对肉仔鸡日增重、料重比的影响均显著(P<0.05),VE、VC的互作效应对肉仔鸡生长后期日增重和料重比的影响均显著(P<0.05);不同的VE、VC处理组之间pH 45 min、pH 12h、pH 24 h值、肉色、肌间脂肪、最大剪切力的差异均不显著(P>0.05),且VE、VC之间无显著的互作效应(P>0.05);不同维生素E组之间的滴水损失率差异极显著(P<0.01),...     

The effect of vitamin C supplementation on plasma concentration and urinary excretion of vitamin C in cattle

We investigated the plasma concentration and urinary excretion of vitamin C in cows supplemented with vitamin C. Five cows (mean BW = 597 kg) were allocated to a 5 x 5 Latin square design and supplemented with a vitamin C preparation coated with hydrogenated soybean oil at 0, 10, 20, 40, or 60 mg of vitamin C per kg of BW per day for 9 d. Plasma and urine samples were collected for measuring vitamin C concentration. Urinary excretion of vitamin C was expressed as the ratio of vitamin C to creatinine. Plasma vitamin C concentration and urinary vitamin C excretion increased quadratically as dietary vitamin C increased (P < 0.001); that is, the lowest dose affected neither plasma vitamin C concentration nor urinary vitamin C excretion but the plasma vitamin C concentration and urinary vitamin C excretion increased (P < 0.05) with increasing supplementation of vitamin C at greater doses. This suggests that plasma vitamin C concentration affects urinary excretion of vitamin C in cattle and that plasma vitamin C concentration exceeded the renal threshold for vitamin C in the cows receiving vitamin C at 20 mg/kg of BW per day. Furthermore, increased urinary excretion of vitamin C appears to limit plasma vitamin C concentration in response to vitamin C intake. The daily excretion of vitamin C was estimated by the reported value of daily creatinine excretion, indicating that the daily amount of vitamin C excreted into urine was more than half of supplied vitamin C. Therefore, a large part of supplied vitamin C probably escapes ruminal degradation and is absorbed but excreted into urine.     

Intravenous vitamin K1 normalises prothrombin time in 1 hour in dogs with anticoagulant rodenticide toxicosis

Four dogs with anticoagulant rodenticide toxicosis were treated with intravenous vitamin K₁ in lieu of plasma transfusion due to client cost constraints. Two dogs experienced a suspected anaphylactoid reaction, necessitating cessation of the treatment in one dog. Prothrombin time was rechecked 1 h after treatment in the remaining three dogs and all results were within the normal reference range. All four dogs were discharged from hospital within 48 h of presentation. Intravenous vitamin K₁ rapidly reverses the coagulopathic state in dogs with anticoagulant rodenticide toxicosis. It is a viable alternative therapy to plasma transfusion if circumstances preclude its use; however, patients must be monitored for anaphylactoid reactions.     

The effect of injectable vitamin C and road transit duration on inflammation,muscle fatigue,and performance in pre-conditioned beef steer calves

This study examined the effects of injectable vitamin C (VC) before transport and duration of transit on feedlot performance, inflammation, and muscle fatigue in cattle. One hundred thirty-two Angus-cross steers (393 ± 4 kg) were stratified by body weight (BW) to a 2 × 2 factorial of intramuscular injection (INJ; 20 mL/steer): VC (250 mg sodium ascorbate/mL) or saline (SAL) and road transit duration (DUR): 18 h (18-h; 1,770 km) or 8 h (8-h; 727 km). On day 0, steers were weighed and given INJ of VC or SAL immediately before transport. Upon return (day 1), BW and blood were collected before steers returned to pens equipped with GrowSafe bunks. Steers were weighed on days 0, 1, 7, 15, 30, 31, 54, and 55. Data were analyzed via ProcMixed of SAS (experimental unit = steer; 32 to 34 steers/treatment) with fixed effects of INJ, DUR, and the interaction. Blood was collected on days −5, 1, 2, 3, and 7 (n = 9 steers/treatment); blood parameters were analyzed as repeated measures with the repeated effect of day. Area under the curve (AUC) for plasma ferric reducing antioxidant power (FRAP) was calculated using R. Final BW was greater for 8 h compared to 18 h (P = 0.05) with no effect of INJ or interaction (P ≥ 0.51). Dry matter intake (DMI) from days 1 to 7 was greater for VC-8, intermediate for VC-18 and SAL-18, and least for SAL-8 (P = 0.02). Overall, DMI tended to be greatest for SAL-18, intermediate for VC-18 and VC-8, and least for SAL-8 (P = 0.08). Days 7 to 31 gain:feed (G:F) was greatest for VC-18 compared to other treatments (INJ × DUR, P = 0.05), and there was no effect of treatment on overall G:F (P ≥ 0. 19). There was no INJ or INJ × DAY (P ≥ 0.17) effect on serum lactate, haptoglobin, or non-esterified fatty acid. However, these blood parameters were greater on day 1 for 18 h compared to 8 h, and both treatments returned to near baseline by day 3 (DUR × DAY, P < 0.01). Plasma ascorbate concentrations on day 1 were greater for VC compared to SAL and returned to baseline by day 2 (INJ × DAY, P < 0.01). Plasma FRAP AUC from days −5 to 3 was greatest for VC-18, intermediate for VC-8 and SAL-8, and least for SAL-18 (INJ × DAY, P = 0.02). This suggests an antioxidant prior to long-haul transit positively influenced antioxidant capacity; however, VC did not improve overall post-transit performance. Although longer transit duration increased indicators of muscle fatigue and inflammation, post-transit performance was not appreciably different between transit durations.     

The effects of antibiotic,probiotic, organic acid,vitamin C,and Echinacea purpurea extract on performance,carcass characteristics,blood chemistry,microbiota, and immunity of broiler chickens

The present context investigated the comparative study on the supplementation of antibiotic, probiotic, organic acid, vitamin C, and herbal extract after vaccination into drinking water and their effects on performance, carcass quality, blood biochemical parameters, immune system, and intestinal flora in broiler chicks for 42 days. A total of 420 one-day-old male broiler chicks (Ross 308) were randomly assigned into 7 treatments with 3 replicates (pens) per treatment and 20 male chicks for each replicate (pen). The experimental treatments consisted of drinking water (control, without additive); drinking water + antibiotic sulfamet; drinking water + C-Vet-50; drinking water + antibiotic sulfamet + C-Vet-50; drinking water + probiotic Primalac; drinking water + butyric acid; and drinking water + extract of Echinacea purpurea Moench (coneflower). There were no differences observed among the treatments for feed intake, but during the whole experimental period, the highest body weight gain was found in the chicks fed with drinking water + antibiotic sulfamet + 50 cc vitamin C (P < 0.05). There were no differences (P > 0.05) observed among the treatments for feed conversion ratio (P > 0.05). Moreover, there were no differences reported among treatments for carcass characteristics at the end of the experiment. Among the treatments, drinking water + 50 cc vitamin C, and drinking water + extract of E. purpurea reduced (P < 0.05) the levels of cholesterol, triglycerides, and low-density lipoproteins. Drinking water + 50 cc vitamin C, drinking water + Primalac, and drinking water + extract of E. purpurea increased (P < 0.05) the lymphocytes count and decreased the heterophils count and heterophil:lymphocyte ratio. The highest Escherichia coli count and lowest Lactobacillus count in ileal content of the broilers were observed in the control group (P < 0.05). The additives used in this study may be incorporated in the drinking water of broiler chickens as growth promoters and for improved performance. A further, wider supplementation study is required to understand the performance, immune system, variation in the intestinal microbial counts, and any other possible alteration in the intestinal biota of the broilers.     

Chronotropic effect of propofol or alfaxalone following fentanyl administration in healthy dogs

ObjectiveTo compare the effect of alfaxalone and propofol on heart rate (HR) and blood pressure (BP) after fentanyl administration in healthy dogs.Study designProspective, randomised clinical study.AnimalsFifty healthy client owned dogs (ASA I/II) requiring general anaesthesia for elective magnetic resonance imaging for neurological conditions.MethodsAll dogs received fentanyl 7 μg kg⁻¹ IV and were allocated randomly to receive either alfaxalone (n = 25) or propofol (n = 25) to effect until endotracheal (ET) intubation was possible. Heart rate and oscillometric BP were measured before fentanyl (baseline), after fentanyl (Time F) and after ET intubation (Time GA). Post-induction apnoea were recorded. Data were analysed using Fisher’s exact test, Mann Whitney U test and one-way anova for repeated measures as appropriate; p value <0.05 was considered significant.ResultsDogs receiving propofol showed a greater decrease in HR (-14 beat minute⁻¹, range -47 to 10) compared to alfaxalone (1 beat minute⁻¹, range -33 to 26) (p = 0.0116). Blood pressure decreased over the three time periods with no difference between groups. Incidence of post-induction apnoea was not different between groups.ConclusionFollowing fentanyl administration, anaesthetic induction with propofol resulted in a greater negative chronotropic effect while alfaxalone preserved or increased HR.Clinical relevanceFollowing fentanyl administration, HR decreases more frequently when propofol rather than alfaxalone is used as induction agent. However, given the high individual variability and the small change in predicted HR (-7.7 beats per minute after propofol), the clinical impact arising from choosing propofol or alfaxalone is likely to be small in healthy animals. Further studies in dogs with myocardial disease and altered haemodynamics are warranted.     

Determination of plasma vitamin C concentration in fattening cattle

Plasma vitamin C (ascorbic acid + dehydroascorbic acid) concentration is a good index of the nutritional status of vitamin C. However, the methodologies for storage and analyses have not been investigated in bovine plasma. The validity of an analytical method for bovine plasma using high performance liquid chromatography (HPLC) with a spectrophotometric detector was examined. Exogenous dehydroascorbic acid was almost completely converted to ascorbic acid during the preparation for analysis with a reducing reagent, dithioerythritol. The analytical recoveries of ascorbic acid were high. Ascorbic acid was not detected after treatment with ascorbic acid oxidase. Thus, the specificity of this method is considered to be high. Although vitamin C was stable in plasma treated by dithioerythritol at ?20°C for 6 days, vitamin C in untreated plasma significantly decreased during 3‐day storage at ?20°C. These results indicate that the HPLC method is suitable for the determination of plasma vitamin C in cattle and that the storage conditions are important for determination of plasma vitamin C. Plasma vitamin C concentration ranged between 1.49 mg/L and 3.33 mg/L in fattening cattle. This result suggests that fattening cattle show large individual variation in plasma vitamin C concentration.     

The effect of ketamine on the MACBAR of sevoflurane in dogs

ObjectiveTo determine the effect of intravenous ketamine on the minimum alveolar concentration of sevoflurane needed to block autonomic response (MAC_BAR) to a noxious stimulus in dogs.Study designRandomized, crossover, prospective design.AnimalsEight, healthy, adult male, mixed-breed dogs, weighing 11.2–16.1 kg.MethodsDogs were anesthetized with sevoflurane on two occasions, 1 week apart, and baseline MAC_BAR (B-MAC_BAR) was determined on each occasion. MAC_BAR was defined as the mean of the end-tidal sevoflurane concentrations that prevented and allowed an increase (≥15%) in heart rate or invasive mean arterial pressure in response to a noxious electrical stimulus (50 V, 50 Hz, 10 ms). Dogs then randomly received either a low-dose (LDS) or high-dose series (HDS) of ketamine, and treatment MAC_BAR (T-MAC_BAR) was determined. The LDS had an initial loading dose (LD) of 0.5 mg kg^?1 and constant rate infusion (CRI) at 6.25 μg kg^?1 minute^?1, followed, after T-MAC_BAR determination, by a second LD (1 mg kg^?1) and CRI (12.5 μg kg^?1 minute^?1). The HDS had an initial LD (2 mg kg^?1) and CRI (25 μg kg^?1 minute^?1) followed by a second LD (3 mg kg^?1) and CRI (50 μg kg^?1 minute^?1). Data were analyzed with a mixed-model anova and are presented as LSM ± SEM.ResultsThe B-MAC_BAR was not significantly different between treatments. Ketamine at 12.5, 25, and 50 μg kg^?1 minute^?1 decreased sevoflurane MAC_BAR, and the maximal decrease (22%) occurred at 12.5 μg kg^?1 minute^?1. The percentage change in MAC_BAR was not correlated with either the log plasma ketamine or norketamine concentration.Conclusions and clinical relevanceKetamine at clinically relevant doses of 12.5, 25, and 50 μg kg^?1 minute^?1 decreased sevoflurane MAC_BAR, although the reduction was neither dose-dependent nor linear.     

Effects of starch and gelatin encapsulated vitamin A on growth performance,immune status and antioxidant capacity in weaned piglets

To evaluate the effects of gelatin and starch encapsulated vitamin A on growth performance, immune status and antioxidant capacity in weaned piglets, a total of 96 weaned piglets (body weight = 9.11 ± 0.03 kg, 30-d-old) were randomly allotted to 3 treatments with 4 replications of 8 piglets each. The 3 treatments were control diet (basal diet without addition of vitamin A), gelatin vitamin A diet (basal diet + 13,500 IU/kg gelatin encapsulated vitamin A), and starch vitamin A diet (basal diet + 13,500 IU/kg starch encapsulated vitamin A), respectively. The results showed that piglets fed starch vitamin A diet had significantly higher final body weight and average daily gain compared to those in control and gelatin vitamin A groups (P < 0.05). Gelatin and starch vitamin A supplementation both highly increased serum retinol concentration and immunoglobulin (Ig) M level when compared with the control group (P < 0.05). Additionally, serum IgA level and glutathione peroxidase (GSH-Px) activity were significantly increased by gelatin vitamin A diet on d 21 and starch vitamin A diet on d 42, respectively (P < 0.05). These results demonstrated that dietary supplementation of vitamin A could improve immune function and antioxidant capacity in weaned piglets, and starch vitamin A is better than gelatin vitamin A, especially in promoting the growth performance of piglets.     

维生素C对蛋鸡新城疫免疫性能的影响

试验将60只体重相近的49日龄海兰褐蛋鸡随机分为A、B、C、D、E5组,每组4个重复,每个重复3只。B、C、D、E4组颈部皮下注射新城疫Ι系疫苗进行免疫,分别在B、C、D、E组日粮中添加0、200、400、800mg/kg的维生素C,分四周测血清中的HI效价及脾脏、胸腺、法氏囊等脏器指数。结果表明:添加维生素C可提高HI效价,对新城疫疫苗免疫效果有促进作用,其中400mg/kg的维生素C效果较好;C、D、E组的脾脏、胸腺、法氏囊等脏器指数均高于B组,说明添加维生素C能促进脾脏、胸腺、法氏囊等免疫器官生长发育,进而影响细胞免疫和体液免疫。     

Analysis of blood clotting with the total thrombus analysis system in healthy dogs

To date, coagulation tests are unable to reflect in vivo coagulation status in the same system, including platelet function, fibrin clot formation, and whole blood flow. The Total Thrombus Analysis System (T-TAS), which is a microfluidic assay that simulates conditions in vivo, measures whole blood flow at defined shear rates under conditions designed to assess platelet function (PL-chip) or coagulation and fibrin clot formation (AR-chip). The T-TAS records occlusion start time, occlusion time, and area under the curve. We evaluated this test in healthy control dogs. We also investigated the effect in vivo of acetylsalicylic acid (ASA), and the effect in vitro of an anticoagulation drug (dalteparin; low-molecular-weight heparin; LMWH). The CV of the AUC of both chips was good (CVs of 6.45% [PL] and 1.57% [AR]). The inhibition of platelet function by ASA was evident in the right-shift in the PL test pressure curve. The right-shift in the AR test pressure curves showed that the administration of LMWH inhibited both platelets and the coagulation cascade. The T-TAS may be useful in the evaluation of canine blood coagulation.