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1.
Approximately 12% of a herd of 68 crossbred cows aborted third-trimester fetuses after consuming moldy peanuts for 4 days. Further investigation revealed that less than 20% of the herd had access to this supplemental feed. Results of serum biochemical analysis indicated liver damage in the affected cows. All of these cows died within 8 days of aborting. The peanuts contained 77 micrograms aflatoxin B1/g, as determined by liquid chromatography. Tissues were submitted from 1 cow, and liver contained 5 ng aflatoxin B1/g. Results of other laboratory tests were negative for common toxins and abortifacients.  相似文献   

2.
Effects of aflatoxin on bovine rumen motility were determined by radiotelemetric techniques. Aflatoxin altered amplitude and/or frequency of rumen contractions in steers given dosages of 0.2, 0.4, 0.6, or 0.8 mg of aflatoxin/kg of body weight. Effects of aflatoxin on rumen motility were dose dependent. An increase in elimination time of aflatoxin from rumen contents was observed in steers given the aflatoxin dosages of 0.4 to 0.8 mg/kg. The increase in elimination time of this toxin facilitates diagnostic capabilities for detecting bovine aflatoxicosis by obtaining rumen contents for analysis for aflatoxin. Aflatoxin M1 was detected in rumen contents from steers at 2 hours after aflatoxin was administered. Thus, intraruminal metabolism of aflatoxin B1 to M1 may occur.  相似文献   

3.
Two of 3 groups of Holstein-Friesian steers (groups II and III; n = 5 each) were fed a ration containing corn naturally contaminated with 800 ng of aflatoxin/g. The other group of steers (group I; n = 5) was fed a ration containing noncontaminated corn. The respective rations were fed for 17.5 weeks, except the ration given to group III; the latter's first diet (contaminated with aflatoxin) was changed to a noncontaminated diet after 15 weeks, continuing for the remaining 2.5 weeks. All steers were killed and tissues and fluids were obtained for aflatoxin analysis. Although aflatoxin B1 and M1 could be detected in blood and urine at several sampling times during the experimental period in groups II and III steers (given the diets containing aflatoxin), there appeared to be no effects on body weight gains and immune phenomena, such as lymphoblastogenesis and antibody production, but there was a waning of the delayed cutaneous hypersensitivity in steers given aflatoxin-contaminated diets. In group III animals (diet was changed to noncontaminated ration at 15 weeks), aflatoxin B1 and M1 disappeared from urine before they were slaughtered. All tissues and fluids, except the rumen contents from these group III steers, were void of detectable aflatoxins B1 and M1 at necropsy. The concentrations of aflatoxin B1 in the rumen content of the latter steers were low. All tissues collected at necropsy from the group II steers fed the aflatoxin diet throughout the 17.5 weeks had detectable aflatoxins B1 or M1 present.  相似文献   

4.
Concentrations of chloramphenicol (C M) were determined, by microbiological assay, in the milk and blood serum of 17 culled dairy cows after intramammary infusion of an approved parenteral CM product (Gloveticol) and in the milk of 16 lactating cows after treatment with two approved CM products for intramammary infusion, at dosages ranging from 1 to 30 g/cow. C M was quickly absorbed from the udder into the blood circulation; the doses of 12.5 and 25 g/cow were almost completely absorbed within 20 hours. Absorption half-life (t1/2ab) from fully functioning quarters was 57+/-18 minutes, and the t1/2ab from partially functioning quarters was 125+/-37 minutes. Mean peak serum C M concentrations were 6.1, 16.2, and 37.4 microg/ml after the cows had been infused with 5, 12.5, and 25 g, respectively. These values were considerably higher than the corresponding peak serum C M concentrations reported following intramuscular injection of equivalent doses of the drug. C M residues were not detectible microbiologically in milk from treated quarters 20 hours after treatment with 5 g or 6.25 g, and 36 hours after treatment with 15 g. Drug concentrations in the milk from the non-treated quarters were approximately 70 per cent of the corresponding serum drug levels. Serum CM concentrations of potential therapeutic value in the treatment of gram-negative bacterial infections, i.e. > 5 microg/ml, were maintained for 8 hours after cows had been infused with 12.5 g, and for 12 hours after infusion with 25 g. The implications of the improved systemic availability of C M infused by the intramammary route over the intramuscular route are discussed in terms of potential therapeutic efficacy, local irritation, and duration of drug residues.  相似文献   

5.
Carbon-14-labeled aflatoxin B1 was prepared by growing Aspergillus parasiticus in medium containing sucrose-14-C as the sole carbon source. The 14-C-labeled aflatoxin B1 was extracted with chloroform and purified by thin-layer chromatography (TLC) followed by precipitation from solution and washing. The 14-C-labeled aflatoxin B1 was intravenously given to anesthetized dwarf White Leghorn or Rhode Island Red hens with cannulated ureters and bile ducts. The 14-C had a calculated plasma half-life of 1.5 minutes and rapidly appeared in the bile. The 14-C concentration in the bile reached values approximately 7 times maximum for plasma, and most could no longer be extracted with chloroform. This finding indicated that metabolites of the 14-C-labeled aflatoxin B1 had been excreted against a concentration gradient into the bile. The quantities of 14-C excreted via bile, urine, and intestinal contents remained at a fairly constant ratio of 70:15:15, respectively, over the 315-minute experimental period. Six major chloroform-soluble compounds containing 14-C were isolated. Three of these were tentatively identified as aflatoxin B1, B2, and M1. A 4th was believed to be aflatoxin B2a. None of the early chloroform-soluble metabolites were as cytotoxic as aflatoxin B1.  相似文献   

6.
奶牛饲料原料中霉菌毒素广泛存在,并严重地威胁着奶牛健康,影响着奶牛生产性能的发挥。本试验选择年龄、胎次、产奶量、泌乳天数相近的荷斯坦奶牛80头探讨日粮添加4种剂量（0g、10g、15g、20g）的霉菌毒素吸附剂对奶牛粪便中双歧杆菌数量和原料奶中黄曲霉毒素残留量的影响。与对照组（添加霉菌毒素吸附剂0g）相比,实验组奶牛粪便中双歧杆菌的外排量明显降低,但各实验组之间统计差异并不显著,仅有数值上的变化。同时,随着霉菌毒素吸附剂含量的增加,原料奶中体细胞数呈现下降的趋势。与试验前相比,原料奶中黄曲霉毒素含量显著降低（P〈0.05）,且随着添加剂量的增加其黄曲霉毒素残留量更少,但添加20g与添加15g相比并无明显变化。研究表明,随着日粮中霉菌毒素吸附剂不同量的添加,均可有效降低原料奶中黄曲霉毒素的残留量,进而提高原料奶质量。  相似文献   

7.
The two possible pathways contaminating milk and milk products with mycotoxins are either the secretory or post-secretory route. The latter is of only little importance due to cooling conditions in production and storage. A secretory contamination can only occur with such mycotoxins, which undergo no complete degradation through their passage into the milk. From the mycotoxins, present in cow's feed; virtually only aflatoxin B1 yields a milkborne metabolite, the aflatoxin M1. The carry over rate is low (2 +/- 1%), but can be enhanced by polyhalogenated biphenyls, also present in the forage. Under normal conditions, however, this enhancement will not be measurable due to low equimolar concentrations of both reactants. The aflatoxin M1 content in herd's bulk milk depends exclusively on the content of the precursor aflatoxin B1 in the ration of the cow and is with less than 10 ng/kg fairly low at present in the Federal Republic of Germany. A careful supervision of the imported feed ingredients for mixed feed, however, will ensure to keep those batches out of dairy cow feeding which exceed a certain level of aflatoxin. The legal threshold is 10 micrograms/kg, being even too high to ensure a milk containing less than 10 ng/kg under high energy feeding conditions. The discussed thresholds for aflatoxin M1 in milk are 50 and 10 ng/kg resp., the latter value is scheduled for milk used in infant nutrition. To keep this low concentration the intake of aflatoxin B1 must be less than 2 micrograms/kg of the daily ration.  相似文献   

8.
Three studies were conducted to determine the potential of experimental feed additives (EFAs), clays or non‐digestible yeast oligosaccharides, to reduce milk aflatoxin (AFM1) concentrations in lactating Holstein cows consuming aflatoxin‐contaminated diets. All studies included a pre‐treatment period and a 2‐week experimental period in a randomized block design. During the pre‐treatment period, cows received a total mixed ration (TMR) with no aflatoxin contamination. During both experimental weeks, all cows were fed a TMR containing aflatoxin‐contaminated corn. During experimental week 1, cows received no EFA’s in the TMR, but EFA’s were included in the TMR for the second experimental week. In studies 1 and 2, the experimental period consisted of 2 weeks each lasting 7 days with 12 cows per treatment. Aflatoxin M1 concentrations were analysed by HPLC for milk samples collected on days 5–7 and days 11–14. In various experiments, treatments included control (no EFA), 100 g/cow daily of experimental Lallemand® product, 10 g/cow daily of MTB‐100®‐2004, (Alltech, Inc.), 10 g/cow daily of MTB‐100®‐2006, (Alltech, Inc.), 10 g/cow daily of experimental Alltech® product (Alltech, Inc.) and 227 g/cow daily of Astra‐Ben 20® (AB‐20®; Prince Agri Products, Inc.). In study 3, the experimental period of 2 weeks each lasting 8 days and milk samples were collected from day 4 to 8 and day 11 to 16. Milk samples from study 3 were analysed for AFM1 concentrations by ELISA. For all experiments, changes in AFM1 concentrations because of the addition of EFA’s were calculated. Four of the five EFAs tested in this study had no significant effect on AFM1 concentrations. However, the addition of AB‐20® resulted in a significant decrease in AFM1 concentrations (60.4%). In summary, the addition of AB‐20® to the diet of cattle appears to be effective for significantly reducing AFM1 concentrations in the milk of cows fed an aflatoxin‐contaminated diet.  相似文献   

9.
奶牛饲料原料中霉菌毒素广泛存在,并严重地威胁着奶牛健康,影响着奶牛生产性能的发挥。本试验选择年龄、胎次、产奶量、泌乳天数相近的荷斯坦牛80头探讨日粮添加4种剂量（0、10、15、20g）的霉菌毒素吸附剂对奶牛粪便中双歧杆菌数量和原料奶中黄曲霉毒素残留量的影响。与对照组（添加霉菌毒素吸附剂0g）相比,试验组奶牛粪便中双歧杆菌的外排量明显降低,但各实验组之间差异不显著,仅有数值上的变化。同时,随着霉菌毒素吸附剂含量的增加,原料奶中体细胞数呈现下降的趋势。与试验前相比,原料奶中黄曲霉毒素含量显著降低（P〈0.05）,且随着添加剂量的增加其黄曲霉毒素残留量更少,但添加20g与15g间无明显变化。因此,本研究表明,随着日粮中霉菌毒素吸附剂添加量的增加,可有效降低原料奶中黄曲霉毒素的残留量,进而提高原料奶质量。  相似文献   

10.
奶牛摄入含有较高黄曲霉菌及毒素的饲料,奶牛代谢功能受到损害,抑制免疫机能,使得乳房炎增加,产奶量下降及奶牛体质下降。黄曲霉毒素B1在奶牛体内转换为黄曲霉毒素M1,并分布在牛奶中,人食用含有超标黄曲霉毒素Ml的牛奶后,能使人发生肝炎、肝癌[1]。作者从事奶牛科学养殖技术服务工作,为了预防和控制奶牛场黄曲霉毒素的危害,提供有关黄曲霉素危害、预防控制措施,有一定的利用性。  相似文献   

11.
The aflatoxin B1 degrading abilities of two different ruminants were compared in this study. One set of experiments evaluated the aflatoxin B1 degradation ability of different rumen fluid donors (steers vs. goats) as well as the rumen fluid filtration method (cheese cloth filtered vs. 0.45 µm Millipore) in a 2 × 2 factorial arrangement. Additional studies examined aflatoxin B1 degradation by collecting rumen fluid at different times (0, 3, 6, 9 and 12 h) after feeding. Cannulated Holstein steers (740 ± 10 kg bw) and Korean native goats (26 ± 3 kg bw) were fed a 60% timothy and 40% commercial diet with free access to water. Rumen fluid from Korean native goats demonstrated higher (p < 0.01) aflatoxin B1 degradability than Holstein steers. However, filtration method had no significant influence on degradability. In addition, aflatoxin degradation did not depend upon rumen fluid collection time after feeding, as no significant differences were observed. Finally, a comparison of two types of diet high in roughage found aflatoxin degradability in goats was higher with timothy hay opposed to rice straw, although individual variation existed. Thus, our findings showed the aflatoxin degradability is comparatively higher in goats compared to steers.  相似文献   

12.
This research compared the toxic effects of aflatoxin B1 and monocrotaline, the active principle of Crotalaria spectabilis, and the additive effect between aflatoxin B1 and monocrotaline in turkey poults. It was of interest whether selenium fed at dosage levels of 0.1, 5, or 10 micrograms/g of feed would protect against the toxic effect of aflatoxin and/or monocrotaline, and whether the toxicants would result in detectable residues in poult tissues. A total of 180 healthy 1-day-old male turkey poults was assigned at random to 12 treatment groups (15 birds/group). Body and liver weight losses, and low serum concentrations in total protein (TP), albumin (A), alpha-globulin (alpha G), and beta-globulin (beta G), as well as high values in gamma-globulin (gamma G), were produced in the groups fed crotalaria. Pathologic changes were induced by monocrotaline with no protection afforded by the added selenium. Low values in TP, A, alpha G, and beta G and in body and liver weights were observed in groups given the combination of aflatoxin plus crotalaria. Gross lesions were associated with an additive toxic effect and a lack of protective effect of selenium against this combination. However, higher values in TP, A, alpha G, and beta G, and liver weights in groups fed aflatoxin B1 plus selenium indicated that selenium had a protective effect against aflatoxin toxicity. Residues of aflatoxin B1 and aflatoxin M1 were found in the kidneys of poults fed aflatoxin B1; also, dehydroretronecine (the metabolite of monocrotaline) was detected in livers of poults fed Crotalaria spectabilis seeds.  相似文献   

13.
黄曲霉毒素(AFs)是存在于食物或饲料中真菌的有毒代谢物,天然产生的AFs主要有AFB1、AFB2、AFG1和AFG2,而AFM1则是AFB1经动物体内转化而来,具有致癌性,可通过牛奶排出,引起牛奶的安全问题。本文综述了牛奶中AFM1的来源与转化,主要国家和组织对奶中AFM1的限量,奶中AFM1的检测方法和控制途径。  相似文献   

14.
Intraruminal and intravenous administration of 3-methylindole (3MI; skatole) caused interstitial pulmonary edema and emphysema in cattle. In 3 adult heifers given the intraruminal dose of 0.2 g of 3 MI per kilogram of body weight, clinical signs of respiratory disease appeared between 6 and 12 hours after dosing, and death due to pulmonary edema and emphysema occurred at 33, 69, and 72 hours. The mean plasma concentration of 3MI became maximal (18.5 mug/ml) at 3 hours and then decreased to low concentrations by 48 hours. In 2 heifers given an intraruminal dose of 0.1 g of 3MI/kg, clinical signs developed, but they did not die during the 96-hour experiment. The mean plasma concentration of 3 MI became maximal (16.8 mug/ml) at 3 hours and decreased to 1.6 and 0.4 mug/ml at 12 and 36 hours, respectively. At necropsy of the heifers, the lung were large, firm, dark red, and heavier than normal. Diffuse pulmonary edema was the predominant change in cattle which died early, and interstitial emphysema was more severe at later stages of the disease. During the early stages, alveoli were overdistended, and a few more ruptured. Most alveolar spaces were filled with proteinaceous residue, but the alveolar septums were smooth and of normal thickness. At later stages, proliferation of alveolar cells was observed, and alveolar septums were thickened. In 3 cows given 0.06 g of 3MI/kg by jugular infusion, clinical signs appeared in all cows, and 1 cow died of pulmonary edema and emphysema 56 hours after the infusion was started. Severe pulmonary lesions seen in all of the cows given a 3MI infusion were similar to those in the cows given an intraruminal dose of 3MI. The mean plasma concentration of 3MI increased to 10.7 mug/ml at 9 hours after starting the infusion and decreased to 0.5 mug/ml at 18 hours. The results indicate that 3MI, a product of ruminal tryptophan fermentation, can cause pulmonary edema and interstitial emphysema in cattle and support the hypothesis that 3MI is the causative agent in tryptophan-induced pulmonary disease.  相似文献   

15.
The method used by Egmond et al. (1979) was chosen from a number of methods recommended for the determination of aflatoxins in raw materials of animal origin. This method is described in detail to facilitate its use in practice in cases of forced slaughters of animals suspected of aflatoxicosis. The sensitivity of the method for aflatoxin B1 and M1 is about 0.05 micrograms . kg-1. On the whole, 88 liver samples were examined for the presence of the aflatoxins B1 and M1. The samples had been obtained from the slaughtered pigs (52), bulls (23), cows (6), calves (5), and from deceased pigs (2). Positive findings were obtained in five of sixteen pork liver samples and in two of the tested five samples of calf liver. All of these animals were suspected of aflatoxicosis. At current slaughter, only one case of 36 examined pigs was found to be positive. Aflatoxin M1 was found more frequently than aflatoxin B1. However, the findings never exceeded the concentration of 100 ng . kg-1; this is less by 1.5 orders than the proposed tolerated concentration for adult animals (5 micrograms . kg-1).  相似文献   

16.
This study was conducted to determine the effects of oral magnesium hydroxide administration on rumen fluid in cattle. Six lactating Holstein cows (4-7 years of age) with rumen fistulas were studied. Cattle were randomly assigned to receive boluses of magnesium hydroxide (162 g) or a powdered form (450 g dissolved in 3.5 L of water) PO daily for 3 days. Analysis of rumen fluid, blood gas tensions, and pH and measurement of serum magnesium concentrations were conducted daily. The study was discontinued after 72 hours, or sooner if rumen pH exceeded 8.0. After at least 3 weeks, the study was repeated with each cow receiving the other form of magnesium hydroxide (powder or bolus). Compared with baseline rumen pH (mean +/- SD: 6.22 +/- 0.28), magnesium hydroxide boluses caused a significant increase (P < .05) in rumen pH after 48 (7.27 +/- 0.11) and 72 (8.01 +/- 0.16) hours of administration, whereas the powdered form caused a significant increase (P < .05) in rumen pH after 24 (7.54 +/- 0.19) and 48 (8.43 +/- 0.22) hours of administration. Both the powdered and bolus forms of magnesium hydroxide decreased rumen protozoal numbers and increased methylene blue reduction times compared with baseline values. There was no change in blood pH, bicarbonate, or base excess values. Serum magnesium concentrations were significantly increased (P < .05) in cows that received the magnesium hydroxide powder. The results of this study indicate that magnesium hydroxide has a potent alkalinizing effect on rumen pH and significantly decreases rumen microbial activity.  相似文献   

17.
为了解日粮能量水平对泌乳奶牛生殖机能的影响,选取年龄、体重、胎次、泌乳量相近的健康泌乳奶牛40头,按添加过瘤胃脂肪量分为高（H,400g/d/头）、中（M,300g/d/头）、低（L,200g/d/头）和对照组（不添加过瘤胃脂肪）四组,每组10头,试验期为产后30d至70d。产后30d、45d、60d、70d以及发情时记录试验奶牛采食量、体况分,记录繁殖性能,检测奶牛血浆GLU、BUN、ALB、TP、LH、FSH、E2、P4和PG浓度,结果显示：1）试验奶牛繁殖性能高低依次为H组、M组、L组和对照组。2）血浆GLU水平H组〉M组〉L组〉对照组;BUN水平L组〉M组〉H组;ALB和TP各组间无差异。3）血浆LH、FSH、E2水平随能量摄入增加而升高。这些结果提示：高能量摄入能缓解奶牛能量负平衡,促进卵泡正常性周期活动,从而提高奶牛繁殖性能。  相似文献   

18.
In the experiment the goat was administered an amount of 450 mg aflatoxin B1. The milk taken during the experiment was lyophilized and aflatoxins B1 and M1 were isolated. After the death of the goat some tissues, blood and bile of the experimental animal were analyzed to find out the aflatoxin content.  相似文献   

19.
A method was developed for percutaneous ultrasound-guided cholecystocentesis in cattle. The procedure was performed on the right side in the 9th, 10th, or 11th intercostal space of 30 cows. Of the 30 cows, 20 were slaughtered 24 hours after cholecystocentesis and the remaining 10 cows were slaughtered after a 10-day observation period. Changes in the peritoneum and gallbladder wall, observed at slaughter, were minimal. During the 10-day observation period, general behavior, attitude, and appetite of the 10 cows were normal. A transient, slight increase in rectal temperature was observed in 6 cows at 4, 5, or 8 days after cholecystocentesis. Total and differential WBC counts and total protein and fibrinogen concentrations, determined daily, were all within normal ranges. Bile samples from 20 cows were examined microscopically and biochemically. Fasciola hepatica and Dicrocoelium dendriticum eggs were observed in bile from 7 and 12 cows, respectively. Fecal examination revealed F hepatica eggs in 4 cows; D dendriticum eggs were not identified in any of the fecal samples. In 1 cow, F hepatica eggs were observed in the feces, but not in the bile. Bile acids concentration in bile varied from 12.5 to 68.5 mmol/L (mean +/- SD, 45.3 +/- 3.05 mmol/L) and in serum from 3.8 to 281.0 mumol/L (41.6 +/- 17.24 mumol/L). Negative correlation was obtained between bile acids concentration in bile and that in serum (r = -0.60, P less than 0.01). It was concluded that percutaneous ultrasound-guided cholecystocentesis in cows is a safe procedure and that microscopic and biochemical examinations of obtained bile can be useful diagnostic aids.  相似文献   

20.
Pyrogallol (1, 2, 3-trihydroxybenzene), the decomposition product of hydrolysable tannins in oak bark, leaves and acorns, is suspected to be poisonous to animals. The aim of our investigations was to correlate clinical signs and pathological findings with pyrogallol concentrations in organs of poisoned and healthy animals. In a field study, pyrogallol concentrations were determined in liver, kidney, and rumen from seven cattle. In a herd of twelve cows, five animals suffered from hemorrhagic diarrhea, anorexia, weakness, rumen stasis, dyspnoea, and colic symptoms. Death was observed in five cows within five weeks after repeated intake of green acorns and oak leaves. Toxicological analyses of rumen content, liver, and kidney specimens of one cattle confirmed the suspicion of pyrogallol contamination. In this animal, values ranged from 6 to 13 ng pyrogallol per gram specimen. In control cattle, concentrations were clearly lower than in perished cattle. Under antioxidative work-up conditions, detection limit was 0.6 ng/g in rumen content and 1.0 ng/g in liver and kidney, respectively.  相似文献   

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