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1.
An in situ technique was adopted to investigate the time-dependent ruminal degradation of chloroplast compared with recombinant DNA of Bt176 corn using conventional and quantitative PCR assays. In parallel, the Cry1Ab protein content and fragment sizes were determined by ELISA and immunoblotting techniques. Triplicate nylon bags filled with 5 g of each substrate (whole-plant isogenic, whole-plant transgenic, ensiled isogenic, and ensiled transgenic corn) were positioned within the rumen of 5 rumen-cannulated, nonlactating cows and incubated for 2, 4, 8, 16, 24, and 48 h. To investigate the DNA degradation process, PCR assays were developed to detect fragments of the endogenous highly abundant rubisco gene (173, 896, 1,197, and 1,753 bp) and of the recombinant cry1Ab gene (211, 420, 727, and 1,423 bp). Short fragments of rubisco (<431 bp) and cry1Ab DNA (211 bp) were amplifiable in whole-plant and ensiled corn samples incubated in the rumen for 48 h, whereas the traceability of larger fragments depended on previous processing of the sample (whole-plant or ensiled corn), the length of the target sequence, and concomitantly on the length of time incubated in the rumen. Quantification of rubisco and cry1Ab gene fragments applying real-time PCR assays revealed degradation to <20% of initial 0-h values within 2 h and <0.5% after 48 h of ruminal incubation. Analysis of Cry1Ab protein in whole-plant corn using the ELISA technique revealed a decrease to 28.0% of the initial value within 2 h and to 2.6% within 48 h. The concentration of Cry1Ab protein of ensiled corn was only 10% that of whole-plant corn. Ensiled corn Cry1Ab protein decreased to 10% of initial values after 48 h of ruminal incubation. Using an immunoblotting technique, the full-size Cry1Ab protein was only detectable up to 8 h; thereafter, only fragments of approximately 17 and 34 kDa size were found. In conclusion, ruminal digestion decreased the presence of functional cry1Ab gene fragments. It is unlikely that full-size, functional Cry1Ab protein will be present after 8 h of incubation in the rumen. Therefore, results based on ELISA measurements should be interpreted carefully and verified by another detection method that discriminates between the full-size and fragmented Cry1Ab protein.  相似文献   

2.
Genetically modified corn Bt11 is insect-resistant and expresses Cry1Ab toxin, an insecticidal protein, in kernels. Although Bt11 corn is considered safe based on animal performance, there are no reports available on the clinico-biochemical effects of feeding it to cattle. In this study, we evaluated the effects of feeding Bt11 to calves, using blood and ruminal clinico-biochemical parameters. Our three-month-long feeding experiment demonstrated that calves (n=6), fed with a ration containing 43.3% of Bt11 corn kernels as dry matter, did not develop any discernible clinical, hematological, biochemical, or ruminal abnormalities as compared with control calves (n=6) fed non-Bt11 corn. The results suggest that the transgenic Bt11 has no negative clinico-biochemical effects on calves.  相似文献   

3.
Maize silage is commonly used as feed for farm animals. The aim of this study was to monitor the time-dependent degradation of non-recombinant chloroplast DNA (exemplified by the rubisco gene) in comparison with the recombinant cry1Ab gene in the course of the ensiling process. In parallel, the Cry1Ab protein content and fragment sizes were determined. Fragments of the rubisco (173, 896, 1197, 1753 and 2521 bp) and of the cry1Ab gene (211, 420, 727 and 1,423 bp) were selected to investigate the DNA degradation process. The detection of the Cry1Ab protein was performed using an enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Rubisco gene fragments of 173 bp were still detectable after 61 days, while fragments of 1,197 and 2,521 bp were detectable up to 30 days and on the first day only respectively. Polymerase chain reaction (PCR) analyses revealed that fragments of the cry1Ab gene with sizes of 211 and 420 bp were detectable up to 61 days, fragments with sizes of 727 and 1,423 bp, 30 and 6 days respectively. The ELISA showed a decrease of the Cry1Ab protein in maize silage during the ensiling process. No marked degradation was observed during the first 43 h. Thereafter, a sharp decrease was measured. After 61 days, 23.6 +/- 0.9% of the initial Cry1Ab protein was still detectable. Immunoblotting confirmed the results of the ELISA showing a positive signal of approximately 60 kDa size for 8 days of ensiling; no further immunoactive fragments were detectable by immunoblotting. In conclusion, the ensiling process markedly decreases the presence of long functional cry1Ab gene fragments and full size Cry1Ab protein.  相似文献   

4.
A long‐term study over 25 months was conducted to evaluate the effects of genetically modified corn on performance of lactating dairy cows. Thirty‐six dairy cows were assigned to two feeding groups and fed with diets based on whole‐crop silage, kernels and whole‐crop cobs from Bt‐corn (Bt‐MON810) or its isogenic not genetically modified counterpart (CON) as main components. The study included two consecutive lactations. There were no differences in the chemical composition and estimated net energy content of Bt‐MON810 and CON corn components and diets. CON feed samples were negative for the presence of Cry1Ab protein, while in Bt‐MON810 feed samples the Cry1Ab protein was detected. Cows fed Bt‐MON810 corn had a daily Cry1Ab protein intake of 6.0 mg in the first lactation and 6.1 mg in the second lactation of the trial. Dry matter intake (DMI) was 18.8 and 20.7 kg/cow per day in the first and the second lactation of the trial, with no treatment differences. Similarly, milk yield (23.8 and 29.0 kg/cow per day in the first and the second lactation of the trial) was not affected by dietary treatment. There were no consistent effects of feeding MON810 or its isogenic CON on milk composition or body condition. Thus, the present long‐term study demonstrated the compositional and nutritional equivalence of Bt‐MON810 and its isogenic CON.  相似文献   

5.
This study examined the influence of transgenic event CBH (StarLink™; SL)-derived hybrid corn on growth, health and physiological functions of pigs, as well as the possibility of transferring the cry9C gene or Cry9C protein to the blood, liver or muscles, in comparison with pigs fed a diet with non-transgenic (isogenic) corn (non-SL). The diet for the SL group was composed of 70% SL corn, and the diet for the non-SL group was composed of 70% non-SL corn. Forty pigs approximately 3 months in age were used in the current experiment. After the pigs were acclimatized to their environment for 7 days, they were fed piglet diets for 7 weeks, and afterwards fed growing-finishing diets until the end of the experiment. There were no significant differences in bodyweight gain, feed intake or feed conversion ratio between the pigs fed SL diet and those of non-SL diet. No abnormalities were observed in the health conditions of either the SL or the non-SL group. Moreover, no significant differences were observed between the two groups in hematological values, histopathological examination and necropsy findings. Although the serum biochemical values within each group were normal, the blood urea nitrogen values of the SL group showed a tendency to be slightly higher than those of the non-SL group. Also, the blood glucose values of the SL group were significantly lower than those of the non-SL group. However, the cause of the significant differences in the blood glucose values between the two groups is unknown. The PCR and ELISA did not detect the cry9C gene and Cry9C protein in the blood, liver or muscles of the pigs at the end of the experiment.  相似文献   

6.
Evaluation of transgenic event CBH 351 (StarLink) corn in broiler chicks   总被引：3，自引：0，他引：3  
The influence of transgenic event CBH 351 (StarLink; SL)-derived hybrid corn on the growth performance, health condition and physiological function in broiler chicks, as well as the possible transfer of the cry9C gene and Cry9C protein to blood, liver and muscle were examined in comparison with chicks fed on a diet with non-transgenic corn (SL-F). Bodyweight gain and feed conversion ratio in the chicks fed on a diet with SL were significantly greater than in chicks fed on a diet with SL-F during the starter phase (0–3 weeks of age), but this significant difference disappeared during the finisher phase (4–7 weeks of age). No abnormalities in health condition in either SL or SL-F groups were observed, and livability did not differ significantly between SL and SL-F groups. Moreover, no significant differences in serum biochemical and hematological values, histopathological observation and necropsy findings were observed between SL and SL-F groups at the end of the experiment. The cry9C gene and Cry9C protein were not detected in blood, liver and muscle of chicks at 3, 5 or 7 weeks of age. The results indicate that feeding SL does not influence growth performance, health condition or physiological function in broiler chicks, and the cry9C gene and Cry9C protein are not transferred to the blood, liver and muscles of broilers.  相似文献   

7.
During the last few years, animal nutrition has been confronted with genetically modified organisms (GMO), and their significance will increase in the future. The study presents investigations on the substantial equivalence of the transgenic Bt (Bacillus thuringiensis) corn and the corresponding nontransgenic hybrid Cesar and parameters of nutrition physiology such as digestibility and energy content for poultry, pigs and ruminants. The results of the analysed corn samples as well as of the silage samples illustrated substantial equivalence in all investigated ingredients, such as crude nutrients, amino acids, fatty acids, minerals and non-starch polysaccharides. The results of the experiments using poultry, pigs, wethers and fattening bulls were not influenced by the genetic modification of corn. The determined values for the digestibilities and the energy contents for poultry, pigs and wethers were not affected by the used corn variety. Neither the examined parameters of the fattening experiments with bulls nor the slaughter results showed any significant differences between the bulls fed on silages made from the nontransgenic or transgenic corn.  相似文献   

8.
Three experiments were conducted to evaluate the impact of the Bacillus thuringiensis (Bt)-11 transformation event in two parental corn hybrids differing in date of maturity on beef and dairy cattle performance. Sixteen lactating Holstein dairy cows in replicated 4 x 4 Latin squares were assigned to four diets in a 2 x 2 factorial arrangement: Bt vs non-Bt trait and early- vs late-maturing corn hybrids. The diets contained 40% of the test corn silage plus 28% corn grain from the same corn hybrid (DM basis). There was no effect of the Bt trait on efficiency of milk production, ruminal pH, acetate:propionate ratio, or in situ digestion kinetics of NDF. The early-maturing corn hybrids resulted in greater total VFA concentrations in the rumen and efficiency of 4% fat-corrected milk production than the later-maturing hybrids (P < 0.05). Sixty-seven steer calves were used in a 70-d corn residue grazing trial for the late-maturing corn hybrids only. Daily BW gain of steers was similar for those grazing Bt and non-Bt corn residues, and the steers exhibited no grazing preference between Bt and non-Bt corn residue. One hundred twenty-eight steer calves were assigned to four silage-based growing diets in a 2 x 2 factorial arrangement: Bt vs non-Bt trait and early- vs late-maturing corn hybrids. The diets contained 90% corn silage and 10% supplement (DM basis). The DMI was higher for steers fed Bt compared with non-Bt hybrids (P < 0.02). An interaction (P < 0.03) was observed for feed efficiency between hybrid genotype and incorporation of the Bt trait. Feed efficiency was greater (P < 0.05) for steers fed the later-maturing non-Bt hybrid compared with the later-maturing Bt hybrid; however, feed efficiency was similar between steers fed early-maturing Bt and non-Bt corn silages. Steers fed the early-maturing hybrid gained 11% faster and were 7% more efficient compared with those fed the late-maturing hybrid. These latter results agree with the dairy experiment in which the early-maturing hybrid resulted in 5% greater efficiency of milk production than the later-maturing corn hybrid. In all experiments, incorporation of the Bt trait into corn had no consistent effect on cattle performance. In addition, background genetics of the corn hybrids appeared to have a more consistent impact on performance than did presence of the Bt trait.  相似文献   

9.
The influence of transgenic event CBH 351 (Starlink)-derived hybrid corn (SL) on the health condition, physiological function and lactational performance of dairy cows as well as the transfer of the cry9C gene and Cry9C protein present in SL to milk, blood, liver and muscles was examined, and compared with a diet containing non-transgenic (isogenic) control corn (non-SL). After adapting to a diet containing non-SL for 2 weeks, four Holstein cows were assigned to each of the non-SL and SL groups and were fed diets containing non-SL or SL, respectively, for 5 weeks. There were no significant influences on the physiological condition, milk yield or serum biochemical and hematological values after feeding with SL. There was also no influence on pH value, cell density of protozoa, or volatile fatty acid concentration and composition of rumen fluids. In addition, no significant differences were observed on histopathological examination of the major organs and tissues between the SL and non-SL groups. Moreover, the cry9C gene and Cry9C protein were not detected by the polymerase chain reaction method and ELISA in the milk, blood, liver and muscles of the cows at the end of the experiment.  相似文献   

10.
The Cry proteins produced by Bacillus thuringiensis are considered to be highly specific insecticidal proteins. Judged to be safe for humans and farm animals due to their insect-oriented selective toxicity, the proteins have been utilized as a biological pesticide and introduced into genetically modified plants. However, some critical fundamental characters of the Cry proteins remain unclear, and the direct effects of activated Cry proteins on mammalian cells have not yet been fully confirmed. Therefore, in this study we employed primary cultured bovine hapatocytes as a model system to determine if Cry1Ab, a Cry protein, affects mammalian cells. There were no significant changes in the secretion of albumin or the morphology of the Cry1Ab-treated cells. The LDH release showed a tendency to increase after the administration of Cry1Ab, but not significantly. Taking these results on bovine hepatocytes into consideration, Cry1Ab has little acute toxicity on mammalian cells.  相似文献   

11.
Muscle glycogen synthesis depends on glucose availability. This study was undertaken to determine the glycemic and insulinemic response of horses to equal amounts of hydrolyzable carbohydrates (starch and sugar) in the form of one of three grain meals or intragastric administration of a glucose solution. In a randomized crossover design, seven horses were fed each of three grain meals (cracked corn, steamed oat groats, or rolled barley) or were infused intragastrically with glucose solution at 2 g of hydrolyzable carbohydrate (starch plus sugar) per kilogram of BW. The quantity of hydrolyzable carbohydrate ingested was not different among all treatments (P = 0.70). Plasma glucose concentration peaked in all four treatments by 1.5 to 2 h after feeding. Plasma glucose concentration remained higher than baseline in oat groats or barley-fed horses throughout 8 h, whereas plasma glucose returned to baseline by 5 to 6 h in corn-fed horses or after glucose administration. Meal consumption was slower in oat groats-fed horses than in corn-fed ones, which may confound the glycemic and insulinemic responses observed after grain feeding. Plasma glucose area under the curve (AUC) was 63% both in corn and oat groats and 57% in barley-fed horses compared with that of horses administered glucose (P = 0.13). Serum immunoreactive insulin concentration peaked between 2 and 3 h after feeding or glucose administration, and barley-fed horses had lower serum immunoreactive insulin concentration by 3 to 4 h than corn-fed horses or after glucose administration (P < 0.05). We conclude, in horses, ingestion of oat groats, corn, and barley result in similar plasma glucose AUC and, compared with the glycemic index of 100 as the glucose reference, corn, oat groats, and barley had a glycemic index of approximately 60.  相似文献   

12.
Two experiments involving 32 growing pigs were conducted to evaluate various concentrations of corn oil, magnesium sulfate, and oat hulls as ameliorants in a high cornstarch-low protein ulcerogenic ration. The pig were slaughtered at the end of the respective feeding periods, and stomachs were evaluated for issue lesions. During a 40-day feeding period, additions of corn oil and of MgSO4 in the rations did not seem to affect development of gastric lesions materially. After a 42-day feeding period, neither 5.0% nor 10.0% concentration of oat hulls in the ration prevented formation of ulcers. Total stomach contents, free gastric HCI, and pH of stomach contents were measured in pigs slaughtered after 3, 6, 9, and 12 hours of fasting. Gastric HCI (mEq/L) differed significantly among pigs fed various rations and increased significantly with length of fasting. The pH of stomach contents did not differ among pigs given various rations, but decreased with length of fasting. Thus, corn oil, MgSO4, or oat hulls did not seem to significantly alter the ulcerogenic character of the high cornstarch-low protein ration.  相似文献   

13.
Two studies were conducted at two locations to evaluate growth performance and carcass characteristics of growing-finishing pigs fed diets containing either YieldGard Rootworm corn (MON 863), a non-transgenic genetically similar corn (RX670), or two conventional nontransgenic corn hybrids (DK647 and RX740). A randomized complete block design with a 2 x 4 factorial arrangement of treatments (two genders and four corn hybrids) was used. Study 1 used 72 barrows and 72 gilts (progeny of Danbred sires x [Danbred x NE White line] dams grown from 22.7 to 117.0 kg BW). Pigs were housed in a modified open-front building in single-gender groups of six (six pens per dietary treatment). Study 2 used 80 barrows and 80 gilts (progeny of PIC 337 sires x C22 dams) grown from 29.5 to 114.9 kg BW. Pigs were housed in an environmentally controlled finishing building in single-gender groups of five (eight pens per dietary treatment). The test corns were included at a fixed proportion of the diet in both studies. Animals had ad libitum access to feed and water. Pigs were slaughtered at the end of the growth period using standard procedures, and carcass measurements were taken. There were no diet x gender interactions for growth performance or carcass measurements in either study. In both studies, overall ADG, ADFI, and G:F were not affected by corn hybrid. There was no effect of corn hybrid on carcass or LM quality measurements in Study 1. In Study 2, LM protein content was less (P< 0.05) for pigs fed RX740 compared with those fed either MON 863 or RX670; however, there was no effect of corn hybrid on other LM composition measures or on quality traits. In both studies, differences between barrows and gilts for growth and carcass traits were similar to previous research. These results suggest that the YieldGard Rootworm corn (MON 863) results in equivalent growth performance and carcass quality to nontransgenic corn hybrids in growing-finishing pigs.  相似文献   

14.
Three experiments were designed to assess the feeding value and potential environmental benefits of feeding degermed, dehulled corn, a low fiber by-product originating from the corn dry milling process, to pigs. Twelve 27-kg (SE = 0.8) barrows were used in Exp. 1 to measure the apparent fecal digestibility of DM, GE and N of degermed, dehulled corn compared with corn grain. Two diets were formulated to contain either 96.4% of degermed, dehulled corn or corn grain plus supplemental vitamins and minerals. Digestibilities of DM, GE, and N were greater in degermed, dehulled corn (96.2, 96.0, and 93.6%, respectively) compared with corn grain (89.0, 89.0, and 78.4%, respectively) (P < 0.01). Overall, a 67 and 29% reduction in DM and N excretion, respectively, was observed. In Exp. 2, eight 70-kg (SE =1.8) barrows were surgically fitted with ileal cannulae and fed the same diets as in Exp. 1, to measure the ileal digestibility of nutrients in degermed, dehulled corn. Ileal digestibility of DM, energy, and N was 13, 15, and 7% greater in degermed, dehulled corn (P < 0.05). Apparent ileal digestibility coefficients of leucine, methionine, and phenylalanine were greater in degermed, dehulled corn compared with corn grain (P < 0.05) while a trend for a lower tryptophan digestibility in degermed, dehulled corn was observed (P = 0.067). In Experiment 3, 96 nursery pigs with an initial average BW of 8.8 kg (SE = 0.08), fed a starter diet formulated with degermed, dehulled corn or corn grain as the major grain source, were used in a 28-d growth performance study. At the end of the study, 24 pigs (1 pig per pen) were sacrificed and gastrointestinal tract measurements were taken. Daily growth rates of pigs were the same between diets (0.64 kg/d). A trend for reduced feed intake (P = 0.073) in pigs fed degermed, dehulled corn led to a 4% improvement in gain to feed (P < 0.05). Feeding degermed, dehulled corn had no effect on gut fill, gastrointestinal tract weight, or liver weight (P > 0.05). Ileal villus lengths and crypt depths were not affected by feeding degermed, dehulled corn although ileal villus widths were greater in pigs fed corn grain. Results from these trials suggest that corn processed to remove poorly digestible fiber fractions provides more digestible nutrients than corn grain. As a result, degermed, dehulled corn reduces fecal and N excretion, thus providing a means to reduce nutrient excretion.  相似文献   

15.
A genetically modified corn hybrid homozygous for the lpa1 allele, containing low phytate (LP), and its nearly isogenic equivalent hybrid (normal) were compared in two experiments with growing-finishing swine. In Exp. 1, 210 barrows (27 kg) were allotted to one of six dietary treatments with two corn hybrids (LP and normal) and three P feeding regimens. There were five replicate pens (seven pigs/pen) per treatment. Treatments consisted of diets that were supplemented with P throughout the growing-finishing period (.2% P and .15% supplemental P during growing and finishing phases, respectively) or only during the growing phase (.2% supplemental P) or that were not supplemented with P throughout the growing-finishing period. Performance at the end of the growing phase was based on a 2 x 2 factorial arrangement of treatments with two corn hybrids and two levels of added P (0 and .2%). This resulted in 10 replicates for the treatments supplemented with .2% P. The finishing phase (73 to 112 kg) was a 2 x 3 factorial arrangement of treatments with the two types of corn and three regimens of added P during the finishing period. Breaking load (BL) and ash of the fourth metacarpal were evaluated from one pig/pen at the end of the growing phase and from all pigs after slaughter. Pigs fed the LP corn diet without added P had greater body weight gain, feed efficiency, BL, and ash content of the fourth metacarpal than pigs fed the normal corn diet without added P. Performance was similar between pigs fed the LP diet without added P and pigs fed LP and normal corn with added P. In Exp. 2, 1,092 gilts (34 kg body weight) were allotted by weight in a commercial facility to one of three treatments: 1) normal corn/soybean meal diet containing .29% and .22% available P during the growing and finishing phases, respectively; 2) LP corn/soybean meal diet with the same available P level as Treatment 1; and 3) same as Treatment 2 for 8 wk, then no inorganic P supplementation during the finishing phase. All pigs were slaughtered at approximately 122 kg. There were no significant differences in growing-finishing performance or BL among treatments. However, pigs fed diets containing LP corn possessed carcasses with less backfat and a higher percentage of lean (P < .01). These results confirm that the P in LP corn is available to the pig and suggest that pigs fed diets containing this genetically modified corn will have more desirable carcasses.  相似文献   

16.
We conducted two studies to determine the bioavailability and apparent digestibility of P in a low-phytate corn hybrid (.28% total P, .10% phytate P) genetically modified to be homozygous for the 1pa1-1 allele and a nearly isogenic corn hybrid (normal) (.25% total P, .20% phytate P). Additionally, we conducted an in vitro assay involving a peptic and pancreatin digestion to estimate P availability. The first study used 50 individually penned pigs (initial body weight 9 kg) and 10 treatments in a randomized complete block design. A cornstarch-soybean meal basal diet (.6% Ca, .2% P) was used. Treatments consisted of the basal diet and the basal diet plus .05, .10, or .15% P from monosodium phosphate (MSP), low-phytate corn, or normal corn. After a 35-d feeding period, pigs were killed to collect the fourth metacarpal for measurements of ash and breaking load. Breaking load was regressed on added P intake, and the bioavailability of P was determined by the slope ratio method. The bioavailabilities of P (relative to MSP) for low-phytate and normal corn were 62 and 9%, respectively. These were similar to the determined in vitro values of 57 and 11% for low-phytate and normal corn, respectively. In the second study, 20 pigs (initial BW 20 kg) were used in a randomized complete block design with a 2 x 2 factorial arrangement of treatments. Two corn lines (low-phytate and normal) and two levels of supplemental P (0 and .2%) from dicalcium phosphate were used. Diets with no added P were formulated to contain .9% lysine, .6% Ca, and .34% P. Apparent nutrient digestibilities were calculated from total collection of urine and feces for 5 d. There were no differences among treatments for energy and nitrogen digestibility. Pigs fed low-phytate corn with no added P had increased digestibility and retention of P and reduced total P excretion (P < .05). We conclude that low-phytate corn contains at least five times as much available P as normal corn. The use oflow-phytate corn greatly reduced the amount of P excreted by the pig and increased the N:P ratio in the manure.  相似文献   

17.
Two studies were conducted at two locations to evaluate growth performance and carcass characteristics of growing-finishing pigs fed diets containing either glyphosate-tolerant Roundup Ready (event nk603) corn, a nontransgenic genetically similar control corn (RX670), or two conventional sources of nontransgenic corn (RX740 and DK647). A randomized complete block design (three and four blocks in Studies 1 and 2, respectively) with a 2 x 4 factorial arrangement of treatments (two genders and four corn lines) was used. Study 1 used 72 barrows and 72 gilts (housed in single-gender groups of six; six pens per dietary treatment) with initial and final BW of approximately 22 and 116 kg, respectively. Study 2 used 80 barrows and 80 gilts (housed in single-gender groups of five; eight pens per dietary treatment) with initial and final BW of approximately 30 and 120 kg, respectively. Pigs were housed in a modified open-front building in Study 1 and in an environmentally controlled finishing building in Study 2. The test corns were included at a fixed proportion of the diet in both studies. Animals had ad libitum access to feed and water. Pigs were slaughtered using standard procedures and carcass measurements were taken. In Study 1, overall ADG, ADFI (as-fed basis), and gain:feed (G:F) were not affected (P > 0.05) by corn line. In Study 2, there was no effect of corn line on overall ADFI (as-fed basis) or G:F ratio. In addition, overall ADG of barrows fed the four corn lines did not differ (P > 0.05); however, overall ADG of gilts fed corn DK647 was greater (P < 0.05) than that of pigs fed the other corn lines. There was no effect (P > 0.05) of corn line on carcass yield or fatness measurements in either study. Differences between barrows and gilts for growth and carcass traits were generally similar for both studies and in line with previous research. Overall, these results indicate that Roundup Ready corn (nk603) gives equivalent animal performance to conventional corn for growing pigs.  相似文献   

18.
以产志贺毒素样大肠杆菌（SLTEC）F18ab血清型标准菌株107/86基因组DNA为模板,利用PCR技术成功扩增出编码F18ab完整菌毛操纵子fed基因,克隆入表达载体pBR322,经限制性内切酶酶切分析,DNA琼脂糖电泳鉴定并结合序列测定分析,构建和筛选出含fed完整基因正确插入的pBR322-fed重组质粒,将上述重组质粒转化至不含任何菌毛结构的大肠杆菌SE5000,该表达重组菌能分别与兔抗F18ab亚单位蛋白FedF高免血清、鼠抗F18ab菌毛a单因子单克隆抗体、兔抗F18ab菌毛高免血清和抗F18ab菌毛IgG抗体产生明显的凝集反应。用热抽提法分别抽提和纯化SLTEC F18ab标准株107/86和重组菌SE5000（pBR322-fed）体外表达的F18ab菌毛,纯化菌毛经SDS-PAGE电泳和考马斯亮蓝染色获单一相对分子质量约为15 000蛋白条带。Western-blotting结果表明：兔抗F18ab菌毛高免血清能特异性识别SLTEC F18ab标准株107/86和重组菌SE5000（pBR322-fed）所提纯的单一主要结构蛋白。用重组菌SE5000（pBR322-fed）进行易感仔猪小肠上皮细胞体外黏附试验和黏附抑制试验,结果表明：重组菌SE5000（pBR322-fed）和SLTEC F18ab标准株107/86一样具有较强的黏附易感仔猪小肠上皮细胞的能力,而兔抗F18ab菌毛高免血清能有效地抑制上述重组菌SE5000（pBR322-fed）和SLTEC F18ab标准株107/86对易感仔猪小肠上皮细胞的黏附结合。  相似文献   

19.
Growth traits with starter and grower pigs and a digestion trial were conducted to compare the nutritional value of Quality Protein Maize (QPM), food corn and conventional feed corn. The QPM, food and feed corn contained .45, .31 and .29% lysine, respectively. The growth trials evaluated a QPM-soybean meal diet formulated on a lysine basis (.96% in starter and .7% in grower diets) and four diets arranged in a 2 (food corn vs feed corn) X 2 (low vs high soybean meal) factorial. Soybean meal was either added in the same amount as in the QPM diet or was added to provide the lysine content of the QPM diet. Performance was similar for pigs fed food corn and feed corn in both trials. The QPM diets resulted in greater performance than food and feed corn diets containing the same level of soybean meal supplementation; starter pigs were more (P less than .10) efficient and grower pigs had a higher (P less than .01) rate and efficiency of gain. However, performance of pigs fed the QPM diets was not equal to that of pigs fed isolysinic food and feed corn diets; growth rate was lower (P less than .05) in starter pigs and gain:feed was lower (P less than .05) in grower pigs. Diets in the digestion trial consisted of the corns plus 3.25% casein. Energy digestibility was similar for all diets. Ileal N and amino acid digestibilities were highest for QPM, intermediate for food corn and lowest for feed corn. In most instances, these differences were significant (P less than .05). Apparent biological value was highest (P less than .05) for QPM. These trials indicate that food corn and feed corn have similar nutritional value, and that starter and grower pigs can benefit from the higher protein quality of QPM.  相似文献   

20.
为了探求乙型脑炎病毒(Japanese encephalitis virus,JEV)基因组cDNA克隆在宿主菌中不稳定遗传的影响因子,本研究以猪源JEV HEN0701株基因组片段1~2913 bp为研究对象,分析基因组原核启动子和相关毒力基因在不稳定遗传中的作用。在5’端,分析片段中潜在的原核启动子序列,通过PCR扩增得到不同长度的cDNA片段;在3’端,通过内切酶酶切截断基因组prM蛋白或E蛋白编码区,获得3’末端不同的cDNA片段。将各片段克隆入pCR-BluntII-TOPO载体,转化大肠杆菌,于37℃条件下培养。结果显示,片段73~2913 bp、97~2913 bp、355~2913 bp及1~933 bp、1~1275 bp能够在转化菌中稳定遗传;含有其他片段39~2913 bp、54~2913 bp及1~1800 bp、1~1971 bp的重组细菌不能在37℃条件下生长;片段1~1600 bp虽然能够在转化菌中传代,但是出现不规律突变。以上结果表明:软件所预测各原核启动子片段中,基因组73~118 bp区域与cDNA克隆稳定性有关,且上游的54 bp至73 bp的序列对该区域启动子存在影响;在JEV基因组1275 bp至1600 bp之间可能存在毒性蛋白编码序列。  相似文献   

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