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1.
A metabolism experiment was conducted with 13 gilts over four periods to investigate the effects of age or weight of pigs, level of inclusion and methods of estimation of apparent digestible (DE) and metabolizable (ME) energy and nutrient digestibility of full-fat palm kernels (FFPK), recombined palm kernel oil and meal (OPKM) and palm kernel oil (PKO). Each palm kernel product was evaluated at levels equivalent to added oil of 40, 80 and 120 g kg−1 in a basal diet. Extracted palm kernel meal (PKM) was also evaluated in the basal diet at the same level as in OPKM. Thus, 13 treatments arranged in four blocks (time periods) constituted the experimental data analysed using a randomised complete block design. Digestible energy and ME contents and apparent digestibility of nitrogen (ADN), dry matter (ADD) and oil (AOD - employing two oil analytical methods) of palm kernel products were estimated by single level assay and by regression with the latter yielding DE values of 40.2, 19.5, 22.1 and 13.1 MJ/kg DM for PKO, FFPK, OPKM and PKM, respectively. The corresponding values for AOD were 1.08, 0.93, 1.03 and 0.88. While the level of inclusion and pig weight (over the range 40–76 kg) did not significantly affect dietary energy and nutrient digestibility of palm kernel products, the form of oil inclusion had considerable effect with OPKM being better utilized than FFPK. Digestibility of oil in the palm kernel products measured by the ether extract (EE) method was, in general, significantly higher than that estimated by the acid ether extract (AEE) procedure. The results suggest the necessity for digestibility coefficients of oils and fats in oil bearing ingredients to be re-evaluated in the light of the currently applied analytical method as figures obtained using the traditional ether extract method may not be applicable to the true nutritional value of feed ingredients and consequently may lead to imprecise diet formulation.  相似文献   

2.
真菌对黄曲霉毒素B_1污染的防治研究   总被引:1,自引:0,他引:1  
黄曲霉毒素是由黄曲霉、寄生曲霉等曲霉属菌株所分泌的毒性次级代谢产物,其中,尤以黄曲霉毒素B1(Aflatoxin B1,AFB1)的毒性、致突变性、致癌性最强,而且其在农作物的栽培、收获、贮藏和加工过程中污染严重,受到全世界的广泛关注。因此,为保证食品的安全性,各国研究人员一直都在寻求安全、高效、经济、环保的方法来控制食品和饲料中AFB1的污染。近年来真菌在AFB1的生物防治方面已取得很大进展,并有部分菌株已应用于生产中。本研究就真菌对AFB1的防治机制及其前景展望进行综述。  相似文献   

3.
Palm kernel press cake (PKC) is a residue of palm oil extraction, which was found to contain 48.5% of total carbohydrates of which 35.2% was mannan. The present study examines enzymatic hydrolysis of polysaccharides from the cell-wall material present in PKC to obtain monosaccharides that can be substrate in various fermentation processes such as ethanol production. The requirements for pretreatment were investigated and it was found that mannan in PKC was readily hydrolysed without any pretreatment. Several enzyme preparations were tested and Mannaway 25L was found as the best for releasing mannose, and Gammanase 1.0L worked well in degrading cellulose and mannose. Binary mixtures of enzymes were tested to increase the conversion, and 1:1 mixture of Mannaway 25L and Gammanase 1.0L showed good synergistic effect releasing 30% more mannose than the sum obtained using these enzymes individually. Using an enzyme loading of 2.3 mg protein/g PKC resulted in 63% of mannan in PKC being hydrolysed to mannose in 24 h, and in 96 h a total of 365 g mannose and glucose could be produced per kg PKC. Finally, PKC was hydrolysed and fermented using Saccharomyces cerevisiae with an ethanol yield of 125 g/kg PKC.  相似文献   

4.
Ngo TA  Kim J  Kim SS 《Bioresource technology》2011,102(5):4273-4276
In this study, fast pyrolysis of palm kernel cake (PKC) was carried out in a closed-tubular reactor over a temperature range of 550 to 750 °C with various retention times. The pyrolyzing gas products mainly included CO, CO2, and light hydrocarbons; it is noted that no hydrogen was detected in the product. In order to investigate the reaction pathway, the kinetic lump model of Liden was applied to verify and calculate all rate constants. The results obtained at different temperatures indicated that the rate constant increased with pyrolysis temperature. Furthermore, the experimental results were in good agreement with the proposed mechanism.  相似文献   

5.
In this paper a survey is described for determination of contamination level of fumonisins (B1, B2, B3) in Indonesian cornbased feed and food samples. The survey was conducted from February to May 2001. Foodstuffs, which are consumed directly such as snacks and other products, were investigated for fumonisin contamination. Of 105 food and feed samples purchased from local retail stores and local poultry shops around Yogyakarta, Java, Indonesia were analyzed using ELISA. Results indicate that 74.3% of samples analyzed were contaminated in a large range of 10.0 – 3307 μg/kg, and the concentration of fumonisins depends on the type of samples. Detection limit of the method used was 9 μg/kg.From eight food samples of maize flour, and corn-based beverages and cereals, none was contaminated (below detection limit). For food samples of industrial products (19 samples), 13 were contaminated in the range of 22.8 – 105 μg/kg and 19 of 20 samples from home made products were contaminated between 12.9 – 234 μg/kg. The food samples contaminated in highest level occurred in corn. Of ten samples, 6 were contaminated from 68.0 – 2471 μg/kg. For feed samples, 17 corn samples were evaluated. Of those samples, 16 contained in a large range of 17.6 – 3306 μg/kg.  相似文献   

6.
A study has been carried out in Argentina on samples of corn genotypes from a breeding station as well as in commercially available corn meal. All samples were analyzed for fungal infection and aflatoxin B1.Mycological analysis of corn genotypes showed the presence of three principal genera of filamentous fungi Fusarium (100%), Penicillium (67%) and Aspergillus (60%). In the genus Fusarium three species were identified, F. moniliforme (42%), F. nygamai (56%) andF. proliferatum (1.8%). Eight species ofPenicillium were identified, the predominant species isolated were P. minioluteum, P. funiculosum and P. variabile. In the genus ranked third in isolation frequency, two species were identified, A. flavus and A. parasiticus, the percentage of infection was 78% and 21%, respectively. Only one corn genotype was contaminated with aflatoxin B1 at a level of 5 ppb. The cornmeal samples showed great differences in fungal contamination, the values ranging from 1 × 101 to 7 × 105 cfu g–1. Fusarium (68%), Aspergillus (35%) and Penicillium (21%) were the most frequent genera isolated. Among the genus, Aspergillus, A. parasiticus (38%) was the most frequent species isolated. All the samples of corn meal were negative to aflatoxin B1. These results indicate a low degree of human exposure to aflatoxins in Argentina through the ingestion of maize or corn meal.This revised version was published online in October 2005 with corrections to the Cover Date.  相似文献   

7.
Aspergillus niger ATCC 6275 possesses the highest carboxymethyl-cellulase, xylanase and -glucosidase activities under liquid and solid cultivations compared withMyceliophthora thermophila IFO 31843 and an isolate, F11. Palm cake proved to be a better substrate for enzyme production and saccharification than palm fibre. Saccharification of these two substrates, using crude enzyme solutions from three fungi and commercial enzymes, was investigated.  相似文献   

8.
Aflatoxins (AFs) are potent sources of health risks to both humans and animals. Among them, AFB1 is the most hazardously toxic and the most frequent in various food commodities, including pistachio nuts. In this survey, the effect of the storage period on AFB1 accumulation on pistachio nuts was investigated. A total of 49 samples collected during the crop year of 2005 from the most cultivated pistachio cultivars in Tunisia were rapidly screened by enzyme-linked immunosorbent assay (ELISA) combined with an immunoaffinity step. The obtained results showed that the contamination of pistachio nuts has occurred clearly after two years of storage for all the tested cultivars except the case of Mateur variety and Thyna ecotypes. In this study, the cultivar Mateur was found to be the most susceptible cultivar to contamination by AFB1. After 4 years of storage, the average contamination levels in nut samples ranged from 2.7 ± 0.3 to 12.7 ± 2.2 μg/kg for AFB1, according to the cultivar. These levels exceeded the maximum permitted limit of 2 μg/kg set by the European Commission in nuts.  相似文献   

9.
Thermal stability of aflatoxin B1 and ochratoxin A   总被引:1,自引:0,他引:1  
Within this research project, the LCI (Lebensmittelchemisches Institut des Bundesverbandes der Deutschen Süßwarenindustrie e. V.) conducted systematic studies to determine the thermal stability of the mycotoxins ochratoxin A (OTA) and aflatoxin B1, as the available literature provides contradictory data. Firstly, the said mycotoxins in pure form were subjected to thermal treament. Secondly, tests were conducted to determine the influence of certain matrix substances, including carbohydrates and proteins, on the thermal decomposition behaviour of the mycotoxins. As a result it can be said that OTA seems to be stable up to 180 °C; however aflatoxin B1 was almost completely degraded at heating temperatures of 160 °C and above. In several model assays it could further be shown that the degradation of mycotoxins is improved by the existence of certain matrix compounds.  相似文献   

10.
The forty-two days long experiment was conducted on a total of 1000 Arbor Acres broilers, divided into two groups. Both groups of broilers were fed with a commercial feed mixture which consisted of standard feedstuffs and contained enough nutrients regarding the requirements. During the first three weeks of the trial, corn naturally contaminated with AFB1 0.0445 ppm per kg dry matter was used in the amount of 20% in the experimental group, while AFB1 free corn was given to birds in the control group. After the period of toxin administration until the end of the trial, broilers from both groups were normally fed another 5 weeks with uncontaminated feed. In the first phase of the trial, broilers in the control groups had an average daily gain (ADG) of 31 g, average daily feed intake (ADFI) of 45 g and a feed: gain ratio (FCR) of 1.42. In the same time, experimental broilers achieved an ADG of 25 g, ADFI of 35 g and a FCR of 1.39. During the whole period of the trial, control and experimental broilers achieved 49.12 g, 95.24 g and 1.94 and 39.71 g, 86.90 g and 2.19, respectively.  相似文献   

11.
In order to select bacterial strains effectively secreting mannanase activity for the production of prebiotic mannooligosaccharides, a two-step screening procedure was performed. Enriched cultures from isolation medium containing copra meal were primary screened on an isolation agar medium containing 1% locust bean gum (LBG), which resulted in 48 mannanase-producing bacterial isolates with significant clearing zones on the mannan-containing agar. However, only nine isolates showed appreciable mannanase activities against copra meal in their culture supernatants (0.054–0.185 U/mg of protein) as determined in a standard assay based on the detection of reducing sugars released from this substrate. The isolates CW2-3 and ST1-1 displayed the highest activity against LBG and copra meal, respectively. Copra mannan hydrolysates that were obtained by using crude mannanase from these nine isolates were further used for a secondary screening towards a growth-enhancing activity on Lactobacillus reuteri and inhibitory activity against Escherichia coli as well as Salmonella Enteritidis, resulting in 0.09–2.15 log CFU/ml enhancing activity and low inhibitory activity of 0.46–1.78 log CFU/ml as well as 0.37–1.72 log CFU/ml, respectively. The hydrolysate of CW2-3 mannanase showed the highest enhancing activity of 2.15 log CFU/ml while isolate ST1-1 was most effective with respect to growth inhibition against E. coli E010 and S. Enteritidis S003 with 0.76 and 1.61 log CFU/ml, respectively. Based on morphological, physical, biochemical and genetics properties, isolates CW2-3 and ST1-1 were identified as Klebsiella oxytoca and Acinetobacter sp., respectively. Crude mannanase activity from these two strains was characterized preliminarily. The pH optima of mannanase activity from Klebsiella oxytoca CW2-3 and Acinetobacter sp. ST1-1 were 7 and 6, respectively. The enzymes were stable at 4°C over a pH range of 3–6 and 3–10, respectively.  相似文献   

12.
J J Pestka  P K Gaur    F S Chu 《Applied microbiology》1980,40(6):1027-1031
A specific microtest plate enzyme immunoassay has been developed for the rapid quantitation of aflatoxin B1 at levels as low as 25 pg per assay. Multiple-site injection of rabbits with an aflatoxin B1 carboxymethyloxime-bovine serum albumin conjugate was used for the production of hyperimmune sera. Dilutions of the purified antibody were air dried onto microplates previously treated with bovine serum albumin and glutaraldehyde and then incubated with an aflatoxin B1 carboxymethyloxime-horseradish peroxidase conjugate. The amount of enzyme bound to antibody was determined by monitoring the change in absorbance at 414 nm after the addition of a substrate solution consisting of hydrogen peroxide and 2,2'-azino-di-3-ethyl-benzthiazoline-6-sulfonate. Antibody titers determined in this manner closely correlated with those determined by radioimmunoassay. Competition assays as performed by incubation of different aflatoxin analogs with the peroxidase conjugate showed that aflatoxins B1 and B2 and aflatoxicol caused the most inhibition of conjugate binding to antibody. Aflatoxins G1 and G2 inhibited the conjugate binding to a lesser degree, whereas aflatoxins M1 and B2a had no effect of the assay.  相似文献   

13.
Certain carcinogens have an effect on the activity of pancreatic deoxyribonuclease I (DNAase I, EC 3.1.4.5). The effect of two potent mycocarcinogens, viz. aflatoxin B1 and sterigmatocystin, as well as the weak carcinogen, aflatoxin B2, on the activity of two nuclear DNAases (DNAases I and II) from rat liver was therefore investigated.  相似文献   

14.
Typically, chemopreventive agents involve either induction of phase II detoxifying enzymes and/or inhibition of cytochrome P450 enzymes (CYPs) that are required for the activation of procarcinogens. In this study, we investigated the protective effects of phloretin against aflatoxin B1 (AFB1) activation to the ultimate carcinogenic intermediate, AFB(1)-8, 9-epoxide (AFBO), and its subsequent detoxification. Phloretin markedly inhibited formation of the epoxide with human liver microsomes in a dose-dependent manner. Phloretin also inhibited the activities of nifedipine oxidation and ethoxyresorufin O-deethylase (EROD) in human liver microsomes. These data show that phloretin strongly inhibits CYP1A2 and CYP3A4 activities, which are involved in the activation of AFB1. Phloretin increased glutathione S-transferase (GST) activity of alpha mouse liver 12 (AML 12) cells in a dose-dependent manner. GST activity toward AFBO in cell lysates treated with 20 μM phloretin was 23-fold that of untreated control cell lysates. The expression of GSTA3, GSTA4, GSTM1, GSTP1 and GSTT1 was induced by phloretin in a dose-dependent manner in AML 12 cells. GSTP1, GSTM1, and GSTT1 were able to significantly increase the conjugation of AFBO with glutathione. Concurrently, induction of the GST isozyme genes was partially associated with the Nrf2/ARE pathway. Taken together, the results demonstrate that phloretin has a strong chemopreventive effect against AFB1 through its inhibitory effect on CYP1A2, CYP3A4, and its inductive effect on GST activity.  相似文献   

15.
An extensive survey of filamentous fungi isolated from wheat grown and consumed in Lebanon and their capacity to produce aflatoxin B1 (AFB1) and ochratoxin A (OTA) was conducted to assess fungi potential for producing these toxins in wheat. From the 468 samples of wheat kernel, collected at preharvest stage from different locations during 2008 and 2009 cultivation seasons, 3,260 fungi strains were isolated with 49.4% belonging to Penicillium spp. and 31.2% belonging to Aspergillus spp. Penicillium spp. was detected on wheat samples with a high amount of P. verrucosum (37.0%). Among the different Aspergillus spp. isolated, A. niger aggregate was predominant and constituted 37.3%. whereas the isolation rate of A. flavus and A. ochraceus was 32.2 and 25.6%, respectively. The ability to produce OTA and AFB1 by isolates belonging to Aspergillus spp. and Penicillium spp. was analyzed by high performance liquid chromatography with fluorescence detector (HPLC-FLD). It was found that 57.0% of Penicillium spp. and 80% of A. ochraceus isolates tested produced OTA, respectively, at maximum concentrations of 53 and 65 μg/g CYA. As for the aflatoxinogenic ability, 45.3% of A. flavus produced AFB1, with maximum concentration of 40 μg/g CYA. A total of 156 wheat samples were analyzed for the levels of OTA and AFB1 by HPLC-FLD. The results showed that 23.7% were contaminated with OTA, at a concentration higher than 3 μg/kg and 35.2% of these samples were contaminated with AFB1 at concentration higher than 2 μg/kg. The risks originating from toxin levels in wheat produced in Lebanon should be monitored to prevent their harmful effects on public health.  相似文献   

16.
Sterigmatocystin (STC) and aflatoxin B1 (AFB1) were analyzed in 246 corn samples, 126 soybean meal samples, and 861 formula feed samples from the Japanese market between April 2010 and March 2015. The detection rate, the highest concentration, and the mean concentration of STC were respectively 14%, 6.4 μg/kg, and 1.2 μg/kg for corn; 14%, 1.1 μg/kg, and 0.63 μg/kg for soybean meal; and 43%, 9.1 μg/kg, and 0.97 μg/kg for formula feed. The detection rate, the highest concentration, and the mean concentration of AFB1 were respectively 46%, 24 μg/kg, and 3.9 μg/kg for corn; 30%, 6.7 μg/kg, and 1.1 μg/kg for soybean meal; and 47%, 20 μg/kg, and 1.6 μg/kg for formula feed. A weak negative correlation between the STC and AFB1 concentrations was observed: there was a high concentration of AFB1 in samples that contained a lower concentration of STC and vice versa. Spearman’s rank correlation coefficient showed a weak negative correlation of ? 0.30 (p < 0.001, n = 128) for corn and ? 0.23 (p < 0.001, n = 575) for formula feed. In conclusion, no correlation was observed between the mean concentrations of STC contamination in formula feed (0.97 μg/kg) and in corn (1.2 μg/kg) and the blending rate (approximately 50%). The rate of STC contamination in the formula feed (43%) was higher than that in corn (14%). Therefore, it is likely that ingredients other than corn contribute to the contamination of formula feed with STC. In this study, regarding STC, problematic samples were not found.  相似文献   

17.
AIMS: Aflatoxin B(1) (AFB(1)) is a mycotoxin which is known to frequently contaminate poorly stored food products destined for human consumption. This study was carried out to investigate the potential activity of lactic acid fermentation in reducing AFB(1) level in fermented maize meal products. METHODS AND RESULTS: Maize meal was spiked with 60 mug g(-1) AFB(1) and fermented, with or without starter culture, for 4 days at 25 degrees C. Unbound AFB(1) in solution and the pH of the media were monitored daily. A significant decrease (P < 0.05) in the level of unbound AFB(1) was observed (75% in the fourth day). Simultaneously, a progressive decrease in the pH of the media from 6.5 to 3.1 was also observed. AFB(1) was below the detection limit in commercial fermented porridge (amahewu) samples. Cytotoxicity tests on AFB(1)-spiked fermented extracts showed that those with a starter culture were comparatively less toxic (30-36%) than those with no added starter culture (24-30%). However, this difference was not significant (P > 0.05). CONCLUSIONS: These results indicate that lactic acid fermentation can significantly reduce the concentration of AFB(1) in maize to trace levels. However, the safety of fermented products has not been well studied, as the mechanism of AFB(1) removal is not well understood. SIGNIFICANCE AND IMPACT OF THE STUDY: Natural fermentation may potentially reduce exposure to natural toxins occurring in food.  相似文献   

18.
Testes from nine male Malin × Santa-Ines rams with an average body weight of 43.1 ± 3.53 kg, were used to study the effects of palm kernel cake (PKC) based diet on spermatogenic cells and to assess copper (Cu) levels in liver, testis and plasma in sheep. Animals were divided into three groups and randomly assigned three dietary treatments using restricted randomization of body weight in completely randomized design. The dietary treatments were 60% palm kernel cake plus 40% oil palm frond (PKC), 60% palm kernel cake plus 40% oil palm frond supplemented with 23 mg/kg dry matter of molybdenum as ammonium molybdate [(NH4)6Mo7O24·4H2O] and 600 mg/kg dry matter of sulphate as sodium sulphate [Na2SO4] (PKC-MS) and 60% concentrate of corn-soybean mix  +  40% oil palm frond (Control), the concentrate was mixed in a ratio of 79% corn, 20% soybean meal and 1% standard mineral mix. The results obtained showed that the number of spermatogonia, spermatocytes, spermatids and Leydig cells were not significantly different among the three treatment groups. However, spermatozoa, Sertoli cells and degenerated cells showed significant changes, which, may be probably due to the Cu content in PKC. Liver and testis Cu levels in the rams under PKC diet was found to be significantly higher (P < 0.05) than rams in Control and PKC-MS diets. Plasma Cu levels showed a significant increase (P < 0.05) at the end of the experiment as compared to at the beginning of the experiment for PKC and Control. In conclusion, spermatogenesis is normal in rams fed the diet without PKC and PKC supplemented with Mo and S. However spermatogenesis was altered in the PKC based diet probably due to the toxic effects of Cu and the significant changes in organs and plasma. Thus, Mo and S play a major role in reducing the accumulation of Cu in organs.  相似文献   

19.
Aflatoxin contamination has been well known as a world-wide health-threatening problem in tropical countries including Indonesia. This research was undertaken to determine the degree of aflatoxin contamination in different Indonesian foodstuffs. A preliminary survey was carried out to evaluate the level of total aflatoxin (AfT) and aflatoxin B1 (AfB1) contamination of baby foods, peanut products, and corn products, which were purchased from traditional markets and supermarkets in Indonesia during the year 2001-2002. Eighty two peanut products, 12 baby foods products, and 11 corn products from different brands were analysed for AfT and AfB1 using the Enzyme-Linked Immunosorbent Assay (ELISA) method. The results indicate that, of the brands analysed, 35% of the peanut products were contaminated with aflatoxins at various levels (range 5 to 870 μg/kg). Peanut-chilli sauces had the highest percentage of AfT contamination 9/12 (75%), which was followed by traditional snacks 5/11 (45%), peanut butter 4/11 (40%), flour egg coated peanut 6/16 (37%), and peanut cake 3/10 (30%). Fried peanuts and roasted peanut were found to contain aflatoxin at relatively lower percentages of 9% and 8%, respectively. From the 12 analysed baby food samples, on the other hand, no sample was found to be contaminated with aflatoxins. Two of 11 samples (18%) of corn based products were contaminated with AfT, ranging between 5.8 and 12.4 μg/kg. Additionally, 30 selected samples in different concentration ranges were further analysed to verify the correlation between ELISA and HPLC techniques and results were compared.  相似文献   

20.
The effects of prolonged oral administration (21 days) of fumonisin B1 (FB1) and aflatoxin B1 (AFB1) were evaluated on male Wistar rats. The animals were housed in individual metabolic cages and submitted to the following treatments: 1-0 g AFB1 + 0 mg FB1/100g bw.; 2-72 g AFB1+ 0 mg FB1/100 g bw; 3-0 g AFB1 + 0.5 mg FB1 g bw; 4-0 g AFB1 + 1.5 mg FB1/100 g bw; 5-72 g AFB1 + 0.5 mg FB1/100g bw; 6-72 gAFB1 + 1.5 mg FB1/100g bw. On day 21, the rats were sacrificed for evaluation. The results showed that treated animals presented differences in body weight and absolute/relative weights of liver and kidney as well as altered hepatic function and cholesterol blood levels. Rats fed with the greatest doses of AFB1 and FB1 gained less weight (2.79 g/day) at the end of the experimental period; their blood concentrations of liver enzymes aspartate aminotransferase (AST) and alkaline phosphatase (AP) were above control levels (130.35 /l and 471.00 /l, respectively). Blood cholesterol increased in the groups treated with the highest dose ofFB1 or FB1 associated with AFB1. Histopathology revealed the occurrence of apoptosis in the liver of rats exposed to FB1. The association of aflatoxin B1 with fumonisin B1 at higher dose probably potentiated the effects of the higher dose of fumonisin B1acting singly.This revised version was published online in October 2005 with corrections to the Cover Date.  相似文献   

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