豆粕中转基因成分检测技术研究

针对豆粕中核酸含量低且被严重破坏,DNA难以提出的问题对CTAB法进行优化,有效地从豆粕中提取到可以用于扩增反应的DNA。同时定性检测出外源调控序列CaMV35S启动子和NOS终止子及目的基因Cp4-EPSPS序列,成功建立了豆粕中转基因成分的检测方法。     

聚丙烯酰胺凝胶电泳在转基因大豆检测中的应用

利用PCR技术，对转基因大豆中CaMV35S启动子、NOS终止子、CP4-EPSPS和大豆凝集素基因进行了定性检测，并且以大豆凝集素基因为内置标准检测了CaMV35S启动子。采用非变性聚丙烯酰胺凝胶电泳和琼脂糖凝胶电泳对PCR扩增产物进行分析，并对两种电泳进行了比较。聚丙烯酰胺凝胶电泳有利于提高定性PCR筛选方法的准确性。     

PCR法定性检测大豆食用油中转基因成分

针对大豆食用油中核酸含量低且被严重破坏、DNA难以提取的问题,对CTAB法进行优化,有效从食用油中提取到可用于PCR扩增反应的DNA模板。同时定性检测出大豆内源基因lectin,外源调控序列启动子CaMV35S、终止子Nos及目的基因CP4-EPSPS序列,成功建立了基于PCR技术在大豆食用油中快速检测转基因成分的方法。     

实时荧光PCR方法检测转基因豆粕的研究

以美国、阿根廷和转基因大豆标准品为材料,利用设计的特异性引物和探针,建立了实时荧光定量PCR技术检测抗草甘膦转基因豆粕的方法,成功检测出美国和阿根廷抗草甘膦转基因豆粕的内源参照基因lectin、CaMV35S/CTP of EPSPS边界序列和NOS终止子,确定了实时荧光PCR方法检测抗草甘膦转基因豆粕的灵敏度为0.1%。     

转基因水稻定性PCR检测体系的建立

采用PCR技术检测CaMV35S启动子、NOS终止子、Bt基因,判断水稻样品中是否含转基因成分,建立了稳定快速的转基因水稻定性PCR检测体系.PCR检测的灵敏度达到0.1%,稳定性良好.结果表明:PCR技术检测外源基因是灵敏和准确的,可以广泛地应用到转基因作物及其加工产品的转基因成分检测中.此外,进一步讨论了转基因成分检测中存在的问题、转基因产品标识的必要性和目前转基因检测技术在检测中的问题.     

抗草甘膦转基因大豆加工品的PCR检测研究

以进口抗草甘膦转基因豆粕、豆粉和中国脱脂大豆为材料,利用设计的特殊引物,建立了PCR技术定性检测抗草甘膦转基因大豆加工品的方法,成功检测出进口抗草甘膦转基因豆粕和豆粉的内源参照基因Lectin、CaMV35S/CTP of EPSPS边界序列和NOS终止子,国产脱脂大豆仅检出内源参照基因Lectin,确定了此PCR技术检测抗草甘膦转基因大豆的灵敏度为0.1%,稳定性良好.     

应用依赖解旋酶DNA扩增技术检测转基因大豆

目的：基于依赖解旋酶DNA恒温扩增（helicase-dependent isothermal DNA amplification,HDA）技术,建立快速检测转基因大豆的方法。方法：采用以CaMV35S、NOS、CP4-EPSPS 3 种外源基因和内源基因Lectin（大豆凝集素基因）为目的片段设计4 对特异引物,建立反应体系,通过HDA方法对内源基因和3 种外源基因的检测特异性和灵敏度进行实验,并对结果进行同源性分析。结果：建立了转基因大豆HDA检测法,检测特异性良好,3 种外源基因的检出限为0.2%。结论：转基因大豆的HDA检测方法具有普通聚合酶链式反应的特异、灵敏等特点,并且对仪器要求更低,极适合基层实验室使用,具有广阔的应用前景。     

应用多重PCR技术快速筛查食品中的转基因成分

以转基因植物中常见的3种筛选调控元件、2种标记基因和1种目的基因为检测靶标,建立了能在一次PCR扩增中同时检测6种转基因成分的多重PCR检测方法。结果表明,当多重PCR体系中Ca MV35S启动子、Fa MV35S启动子、NOS终止子、bar基因、NPTII基因、CP4-EPSPS基因的检测引物浓度分别为0.2、0.2、0.3、0.3、0.2、0.2μmol/L,退火温度为60℃时扩增效果最佳,利用优化后的六重PCR方法可从转基因玉米、大豆、棉花、油菜等各类样品中精准检测出相应的转基因成分,方法的检测灵敏度可达到0.1%。该方法为食品中常见转基因成分的筛查提供了一种高效的手段,在转基因产品的检测工作中具有较高的应用价值。     

转基因玉米的七重PCR鉴定方法

以玉米内源基因IVR、外源抗除草剂基因(BAR、PAT)、抗虫基因Cry1Ab、筛选基因NPTII、CaMV35S启动子和NOS终止子为检测的目的片段,分别设计了7对引物,通过研究较佳引物终浓度配比和退火温度,建立了玉米转基因成分七重PCR检测体系。结果表明,建立的七重PCR体系用于同时检测内源基因和转基因成分是可行的,检测方法效率高、稳定性好。     

转基因玉米成分定性检测能力验证结果与分析

目的提高检测实验室对转基因玉米成分的检测能力和检测人员专业技术水平,增强实验室竞争力。方法中心实验室依据能力验证作业指导书和农业部公告的要求,参与了ACAS-PT570(2018)粮食转基因检测能力验证测试,分别对编号18-F750和18-K388样品进行PCR检测。结果 18-F750和18-K388待测样品中, CaMV35S启动子、FMV35S启动子、NOS终止子、Bt基因、CP4 EPSPS基因、bar/pat基因、59122转化体、MIR162转化体和Bt11转化体均为阳性。结论本次能力验证获得满意评价。     

Influence of rapeseed cake, linseed cake and hemp seed cake on laying performance of hens and fatty acid composition of egg yolk

In hens the effects of expeller/cakes from rapeseed, linseed, and hemp seed were investigated on feed intake, laying performance and fatty acid composition of egg yolk. A total of 216 individually caged laying hens were allocated to nine dietary treatments (5, 10, 15 % cake) and fed for six laying months. For feed intake, egg mass production and feed-to-egg mass ratio at 15 % dietary cake level a significant lower performance was shown compared with the 5 and 10 % cake level groups. Also interaction was significant for all these parameters, indicating that the cake level acted differently for the three cakes. The egg mass production was lower in the linseed cake than in the hempseed groups and the hens fed the linseed cake needed significantly more feed per kg egg mass compared with both the other cakes tested. Increasing dietary level of all oil seed cakes lowered the yolk percentage and increased the egg white percentage. Increased dietary levels of all three oil seed cakes lowered the percentages of most saturated fatty acids and also the percentages of the monounsaturated fatty acids. The linoleic acid and the linolenic acid as polyunsaturated fatty acids were heightened by increasing the cake levels from 5 to 10 and 15 % in the diet. The results allow the conclusion that compound feeds with up to 10 % of cakes does not negatively influence the laying performance of hens and provides the possibility of the enrichment of yolk fat with polyunsaturated fatty acids.     

Genetically Modified Feeds in Poultry Diet: Safety,Performance, and Product Quality

Concerns have been expressed regarding the safety of using biotechnology derived feeds in diets of livestock animals and in regard to human consumption of products from species fed transgenic crops. As a consequence, a large number of poultry nutrition studies have been conducted to evaluate the wholesomeness of transgenic crops by examining performances of animals during growth or egg laying. Studies also evaluated whether foreign DNA and proteins could be detected in meat, egg, and tissue samples from broiler chickens and laying hens fed diets containing transgenic feeds. In all studies, the conclusions were in agreement that the transgenic crops provided comparable performance, carcass and egg yields, and meat and egg composition, when compared with conventional grains. Moreover, it was demonstrated that transgenic proteins and DNA present in livestock feeds are not detectable in food products derived from these animals, using the most sensitive detection methods available, confirming that they are rapidly degraded by normal digestive processes. The lack of significant differences were a result of the similarity in nutrient composition of the genetically modified feeds and lack of differences in intake and digestibility, while there were no evidences that the differences reported for performance response variables and carcass measurements between treatment groups were attributable to the presence of the transgenic gene and protein in the biotechnology derived plants. Results demonstrated that genetically modified feeds are substantially equivalent and they result as safe as existing conventional feeds.     

The residue levels of narasin in eggs of laying hens fed with unmedicated and medicated feed

Laying hens were fed contaminated feed containing narasin 2.5 mg/kg for 21 days followed by a 7 day withdrawal period, hens in the control group were fed unmedicated feed. Eggs were collected during trial days 0, 3, 7, 14, 21 and after the withdrawal period of 7 days. The concentration of narasin in yolks and egg whites was analyzed by a liquid chromatography-mass spectrometry method. Narasin was found to accumulate in yolks, where the narasin concentration increased during the treatment. The concentration of narasin varied from 5.9 to 13.8 microg/kg (mean 10.6 microg/kg) in yolks after 21 day feeding periods. The concentrations of narasin ranged from < 0.9 to 1.4 microg/kg after the withdrawal period. Narasin residues were not found in egg whites of the laying hens fed contaminated feed nor in either yolks or egg whites of the laying hens fed unmedicated feed. The effect of cooking was also tested on the amount of narasin residues in eggs. Cooking for 10 min did not significantly influence the narasin residues in eggs. Traces of lasalocid were also found in the yolks. The traces of lasalocid are attributable to an accidental contamination of the feed during its manufacture.     

Petals of Aztec Marigold, Tagetes erecta, as a Source of Pigment for Avian Species

SUMMARY—The deposition of the pigments of Aztec marigold petal was determined in the egg and tissue of laying hens fed 33–66 and 99 mg of the pigments per kg of low pigment diet. Thirty-three mg pigment per kg of feed produced yolk color which is considered acceptable to the consumer. With an increase in the amount of pigment in the feed, color deposition in the organs increased, but efficiency of utilization was lowered.     

Deposition and depletion of maduramicin residues in eggs after oral administration to laying hens determined by LC-MS

The coccidiostat maduramicin has been approved as a feed additive for chickens and turkeys, although it is prohibited for use in laying hens. In the present study, laying hens were divided into three groups and fed for 14 days with medicated feed containing maduramicin, at three different concentrations: 50, 100 and 500 µg kg^?1. Eggs were collected during treatment and for 26 days after the end of feeding with medicated feed. Maduramicin residues were found exclusively in egg yolk, with the highest concentration in egg yolk of 459 µg kg^?1 for the highest dose. The maximum concentration of maduramicin in whole egg was 16.6 µg kg^?1 for the group receiving feed containing the maximum permitted level of maduramicin in feed (50 µg kg^?1). The half-life of elimination of maduramicin, calculated for post-treatment days 1–10, was 6.5 days. Twelve days after drug administration, the concentration of the maduramicin in egg yolk for Group 3 (fed with 500 µg kg^?1 maduramicin) still exceeded 20 µg kg^?1, while the concentrations for Groups 1 and 2 were 1.2 and 2.7 µg kg^?1, respectively.     

Aflatoxin B1 residues in eggs of laying hens fed a diet containing different levels of the mycotoxin.

The present study was carried out to evaluate the excretion of aflatoxin B1 residues in eggs of young laying hens fed aflatoxin B1-contaminated rations for 8 weeks. To this end, 96 twenty-week-old hens were randomly distributed into four experimental groups (24 birds per group) and given rations containing either 0 (controls), 100 micrograms, 300 micrograms or 500 micrograms aflatoxin B1/kg feed. Egg aflatoxin B1 residues were determined by thin layer chromatography; two samples per treatment per week were used for analysis. Egg production and average egg weights were not affected (p < 0.05) in the groups receiving aflatoxin B1-contaminated rations. Residues of aflatoxin B1 were detected only in the eggs of hens given 500 micrograms/kg feed, at levels that ranged from 0.05 to 0.16 microgram/kg (average: 0.10 microgram/kg). The results indicate that the feed to eggs aflatoxin B1 transmission ratio was approximately 5000:1, emphasizing the importance of controlling aflatoxin levels in rations for laying hens.     

The Influence of Feeding Yellow-, Green- and Brown-Seeded Peas on Production Performance of Laying Hens

Two experiments were conducted to evaluate the feeding value of yellow-, green- and brown-seeded peas as protein and energy supplements in laying hen diets. In experiment 1, all three types of peas were included in laying hen diets at 0, 200, 400 and 600 g kg^-1 replacing wheat and soya bean meal. Layers fed diets containing peas at 200 g kg^-1 produced more (P⩽0·05) eggs, had higher (P⩽0·05) egg mass output and better (P⩽0·01) feed conversion than those fed the wheat soya bean meal control diet. With 400 g peas kg^-1 in diets, egg production, egg mass and feed conversion were similar (P⩾0·05) to the control diet. Total replacement of soya bean meal with peas (600 g peas kg^-1 in diets) reduced (P⩽0·01) egg production, egg mass and feed conversion. A progressive (P⩽0·01) improvement in yolk colour as the level of peas in the diet increased was observed. Shell quality decreased (P⩽0·05) with increasing levels of yellow or brown peas in the diets, however, it seemed not to be affected by green peas. Daily feed intake, egg weight and mortality rates were not affected by dietary treatments. The influence of feeding diets containing yellow or brown peas supplemented with varied levels of methionine on production performance of laying hens was investigated in experiment 2. The dietary treatments consisted of a 400 g kg^-1 yellow or brown pea diet supplemented with three levels of methionine to 100, 115 and 130% of the NRC requirements. Methionine supplementation to either 15 or 30% above NRC requirement for laying hens had no significant (P⩾0·05) effect on all production parameters. It can be concluded that the inclusion of yellow, green or brown peas into laying hen diets up to 400 g kg^-1 does not affect production performance. The NRC recommendation of methionine requirement for laying hens is adequate to support maximum egg production for diets containing moderate quantities of peas. © 1997 SCI.     

The influence of different single dietary sources on moult induction in laying hens

An investigation was carried out to assess the possibility of using single dietary sources as alternatives to feed deprivation for the induction of moult in commercial laying hens. The study involved six dietary groups of 29 laying hens: unmoulted, dried tomato pomace, alfalfa meal, rice bran, cumin seed meal and feed withdrawal. The birds received the above diets during the moulting period (11 days), and body weight loss and ovary weight regression were measured. Post‐moult production parameters (number of eggs produced per hen per day, egg weight, shell weight, yolk colour and Haugh unit) were measured for 12 weeks. Results showed that all dietary sources were as effective as feed withdrawal in causing ovary weight regression in birds. Birds provided with tomato pomace or alfalfa showed lower weight losses than feed‐deprived birds at the end of the moulting period. Hens moulted by tomato pomace or alfalfa exhibited post‐moult levels of egg production over a 12 week period that were superior to those of hens moulted by feed withdrawal. Post‐moult eggs laid by hens moulted by all dietary sources were of comparable quality to eggs from feed‐deprived hens and superior to those from unmoulted hens. As fibrous feeds with low metabolisable energy and an appreciable amount of protein, dried tomato pomace and alfalfa meal may be fed to hens on an ad libitum basis for effective moult induction while reducing the stress of severe starvation and retaining comparable egg quality and production. Copyright © 2007 Society of Chemical Industry     

Value of yeast protein for poultry feeds

Evaluation of yeast as a main source of protein to replace fish meal or soybean meal in chicken feeds was reviewed in the attempt to establish another source of protein in chicken nutrition. Various substrates used for yeast growth were compiled. The chemical composition and vitamin B content of yeasts were summarized. Amino acids and nucleic acids of yeasts as well as net protein utilization, true digestibility, biological value, and protein efficiency ratio of yeasts and other protein foods were discussed to ascertain the nutritive value of yeast proteins. The results of studies conducted under practical conditions where yeasts were used to replace the extracted soybean meal and fish meal individually or together in commercial feeds were tabulated in detail in terms of growth, feed intake, feed conversion ratio, etc. It appeared that the growth of broilers fed the feeds containing yeast at a level of up to 15 to 20% was almost identical when yeast was added in place of soybean meal, but somewhat retarded when yeast was added in place of all fish meal and part of soybean meal. Poorer growth was observed with an increase in dietary yeast above this level. It was recommended to add synthetic DL‐methionine to yeast‐based rations for poultry in order to obtain good growth performance. It has been demonstrated that appetite and growth rates of broilers maintained on yeast‐containing diets properly balanced in energy, protein, calcium, and phosphorus were superior to those in which the nutrients were not carefully adjusted. The blood plasma uric acid levels of broilers were not affected by levels of up to 20% n‐paraffin yeast in the diet. Up to 20% of the diet can be composed of alkane‐grown yeasts without any deleterious effects on egg quality or reproductive performance of laying and breeding hens. Chickens fed for prolonged periods of time with hydrocarbon‐grown yeasts failed to show any changes in protein metabolism, hematologic, or morphological indices which might be associated with undesirable characteristics of poultry products.     

The effects of sources of supplemental fat on performance,egg quality,and fatty acid composition of egg yolk in laying hens

BACKGROUND: The objective of this study was to determine the effects of sources of supplemental fat on laying performance, egg quality, and fatty acid composition of egg yolk. RESULTS: Two hundreds Isa Brown layers were assigned randomly to be fed ad libitum a standard commercial layer feed (BD), basal diet plus 2% tallow (T), basal diet plus a mixture of 1% tallow and 1% flaxseed oil (MTFO), basal diet plus 2% sunflower oil (SO), or basal diet plus 2% flaxseed oil (FO), which were offered for 8 weeks. Each diet was given to five groups, each containing 10 hens. The feed efficiency and egg production were 2.78 and 53.51% for BD; 2.30 and 63.47% for T; 2.45 and 60.14% for MTFO; 2.29 and 64.30% for SO, and 2.62 and 61.18% for FO groups, respectively. Dietary fat supplementation affected the laying performance but had no significant effects on egg quality parameters. The fatty acid composition of egg yolk lipids were significantly affected by dietary fatty acid composition. The supplemental tallow increased palmitic fatty acid. The proportions of linoleic and arachidonic fatty acids in egg yolks for layers fed the SO diet were higher than in the BD group and those on diets containing other fats. Concentrations of oleic and omega‐3 fatty acids were the highest in layers fed the FO diet during the laying period. CONCLUSION: The results indicated that dietary animal and plant fats changed the fatty acid composition of egg yolk. Copyright © 2008 Society of Chemical Industry