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PubMed1998

Influence of tempering on the feeding value of rolled corn in finishing diets for feedlot cattle.

Crossbred yearling steers (n = 125; 372 kg) were used in a 109-d finishing trial. Steers were fed an 88% concentrate diet containing 65% corn (DM basis) as 1) dry rolled corn (DRC); 2) tempered rolled corn (TRC), 43 mg surfactant (SarTemp)/kg corn; 3) TRC, 172 mg surfactant/kg corn; 4) TRC, 430 mg surfactant/kg corn; and 5) steam-flaked corn (SFC). Corn moisture was greater (3.5%, P < .01) for TRC than for DRC but less (10%, P < .05) than for SFC. Starch enzymatic reactivity was less for TRC than for either DRC (18%, P < .05) or SFC (42%, P < .01). Tempering increased the integrity of rolled corn and reduced the amount of particles less than 2 mm in diameter by 54% (P < .01). Steam flaking corn increased (P < .01) proportion (78%) of the grain having a particle size distribution of greater than 8 mm, as compared with TRC (25%) and DRC (3%). Compared with DRC, tempering enhanced (P < .10) ADG (9%), feed efficiency (5%), and dietary NE (3%). Daily weight gain was similar (P > .10) for TRC and SFC. Feed efficiency (P < .10) and dietary NE (P < .01) were greater (6%) for SFC than for TRC. There were no differences (P > .10) between DRC and TRC in ruminal and total tract digestion of OM, N, and starch, and in ruminal microbial efficiency. Ruminal digestion of OM decreased (linear effect, P < .05) and ruminal microbial efficiency increased (linear effect, P < .05) with increasing surfactant concentration. Ruminal digestion of OM and starch, and flow of nonammonia N to the small intestine were greater (31, 56, and 14%, respectively, P < .01) for SFC than for TRC. Postruminal and total tract digestion of OM, N, and starch, and dietary DE were greater (P < .01) for SFC than for TRC. We concluded that tempering corn will enhance animal performance. Increasing the concentration of surfactant used in tempering may enhance ruminal microbial efficiency and lean tissue growth.

Adipose Tissue↗
PubMed2000

Phosphorus bioavailability and digestibility of normal and genetically modified low-phytate corn for pigs.

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.

Animal Feed↗
PubMed2002

Effect of corn processing on degradable intake protein requirement of finishing cattle.

Three finishing trials were conducted to determine effect of corn processing on degradable intake protein requirement (DIP) of feedlot cattle. In Trial 1, 252 steers were fed 90% concentrate, high-moisture corn-based diets that contained 0, 0.4, 0.8, or 1.2% urea (DM basis) to provide dietary DIP values of 7.0, 8.2, 9.3, and 10.5% of DM, respectively. Nonlinear analysis predicted maximal feed efficiency at 10.2% dietary DIP (95% confidence interval was 9.9 to 13.3%). In Trial 2, 264 steers were fed 90% concentrate, steam-flaked corn-based diets that contained 0, 0.4, 0.8, 1.2, 1.6, or 2.0% urea (DM basis) to provide dietary DIP values of 4.7, 5.8, 7.0, 8.2, 9.3, and 10.5% of DM, respectively. Nonlinear analysis predicted maximal feed efficiency at 7.1% dietary DIP (95% confidence interval was 7.0 to 7.2%). In Trial 3, 90 individually-fed steers were fed 90% concentrate, dry-rolled, high-moisture, or steam-flaked corn-based diets. Urea was factored across diets at 0, 0.5, 1.0, or 2.0% of DM to provide dietary DIP values of 4.8. 6.3, 7.8, 9.2, and 10.7% for dry-rolled, 6.7,8.1,9.6, 11.1, and 12.5% for high-moisture, and 4.7, 6.1, 7.6, 9.0, and 10.5% for steam-flaked corn-based diets, respectively. For the dry-rolled corn-based diet, nonlinear analysis could not predict a requirement because feed efficiency was not improved beyond the first increment of dietary DIP, suggesting that the DIP requirement was met at 6.3% of DM. For the high-moisture corn-based diet, nonlinear analysis predicted maximal feed efficiency at 10.0% dietary DIP (95% confidence interval was 9.2 to 11.3%). For the steam-flaked corn based diet, nonlinear analysis predicted maximal feed efficiency at 9.5% dietary DIP (95% confidence interval was 9.2 to 9.5%). Our estimate of the DIP requirement for dry-rolled corn-based diets (6.3%) agrees well with past research and predicted values. Our estimate of the DIP requirement for high-moisture corn-based diets (10.1%) was very consistent between trials and higher than predicted. Our estimates of the DIP requirement for steam-flaked corn-based diets varied from 7.1 to 9.5%, with an average of 8.3% of dietary DM.

Animal Feed↗
PubMed2005

Differential responses to dietary cobalt in finishing steers fed corn-versus barley-based diets.

An experiment was conducted to determine the effects of dietary Co concentration on performance, carcass traits, and plasma, liver, and ruminal metabolites of steers fed corn- or barley-based diets. Sixty steers, initially averaging 316 kg, were stratified by BW and assigned randomly to treatments in a 2 x 3 factorial arrangement, with factors being a corn- or barley-based diet and supplemental Co added at 0, 0.05, or 0.15 mg/kg of DM. Control corn-and barley-based diets analyzed 0.04 and 0.02 mg of Co/kg of DM, respectively. Steers were fed individually using electronic Ca-lan gate feeders. Cobalt supplementation increased (P < 0.05) DMI and ADG over the total study. From d 85 to finish, Co supplementation increased (P < 0.05) ADG by steers fed corn- but not barley-based diets. The G:F was increased (P < 0.05) by Co supplementation during the first 84 d but not over the entire finishing period. Average daily gain and G:F were greater (P < 0.05) for corn- vs. barley-fed steers. Supplemental Co increased vitamin B12 in plasma and liver (P < 0.05), and plasma vitamin B12 was greater (P < 0.05) in steers fed corn-vs. barley-based diets. Cobalt supplementation increased (P < 0.05) ruminal fluid vitamin B12 on d 84 in steers fed corn- but not barley-based diets. Folate was greater in plasma (P < 0.01) and liver (P < 0.05) of steers fed Co-supplemented diets. Increasing supplemental Co from 0.05 to 0.15 mg of Co/kg of DM increased (P < 0.05) liver folate in steers fed barley- but not corn-based diets. Supplemental Co decreased (P < 0.01) plasma methylmalonic acid concentration in steers. Increasing supplemental Co from 0.05 to 0.15 mg/kg of DM decreased plasma and ruminal succinate concentrations, and steers fed barley-based diets had greater (P < 0.05) plasma and ruminal succinate relative to those fed corn-based diets. Addition of supplemental Co to the basal diets increased (P < 0.01) plasma glucose concentrations of steers, and steers fed corn-based diets had greater plasma glucose than those fed barley-based diets. Steers supplemented with Co had greater ruminal propionate (P < 0.01) and lesser (P < 0.05) ruminal acetate and butyrate proportions than controls. Supplemental Co increased dressing percent (P < 0.10) and HCW (P < 0.01) at slaughter. These results indicate that feeding steers corn- or barley-based diets deficient in Co adversely affects performance and vitamin B12 status.

Animal Feed↗
PubMed2005

Effects of pasteurization of potato slurry by-product fed in corn-or barley-based beef finishing diets.

Pasteurization of vegetable by-products such as potato slurry (PS) before feeding may be necessary to prevent the spread of pathogens and beef carcass blemishes. We hypothesized that pasteurization would increase ruminal fermentability of PS starch. Four ruminally cannulated crossbred beef steers (initial BW = 432) were used in a 4 x 4 Latin square experiment with a 2 x 2 factorial arrangement of treatments to examine the main effects and interactions of pasteurization (54.4 degrees C for 2 h) of PS and grain type (GT; dry-rolled corn and barley) on ruminal and total tract digestion of beef finishing diets. Diets contained 7% alfalfa hay and 14% PS (DM basis) and were fed ad libitum three times daily. Corn-based diets had 71.7% corn, whereas barley-based diets had 60% barley and 11.7% corn. Pasteurization resulted in greater (P = 0.004) soluble, rapidly degradable starch (34.3 vs. 26.7% for pasteurized and nonpasteurized PS, respectively). Ruminal fluid pH was more acidic (P < 0.07) for corn-based diets than for barley-based diets (P = 0.07) at 0200 and 2100 (sample time x GT; P < 0.05). Ruminal fluid pH was more acidic (P = 0.06) at 1400 for corn-based diets containing pasteurized PS compared with other dietary treatments (sample time x pasteurization x GT; P = 0.04). Minimum and maximum ruminal pH were greater (P < 0.10) for barley-based diets than for corn-based diets. Ruminal fluid pH was < 6.0 for a greater (P = 0.04) proportion of the day for corn-based compared with barley-based diets. In vitro incubation measurements revealed that pasteurization of PS resulted in lower (P = 0.06) ruminal fluid ammonia N concentration. Ruminal fluid ammonia N concentration was lower (P = 0.11) for barley-based diets than for corn-based diets. Steers fed barley-based diets had greater (P = 0.02) DMI and lesser (P < 0.05) total tract digestibility of DM and ADF compared with steers fed corn diets. Pasteurization increased (P = 0.10) total tract starch digestibility. Results indicate pasteurization increased rapidly degradable starch, ruminal starch fermentability, and total tract starch digestibility of PS. Grain type interacted with pasteurization such that feeding corn-based diets containing pasteurized PS resulted in periodic reductions in ruminal pH. Feeding management may be more critical when feeding pasteurized PS in beef finishing diets.

Animal Feed↗
PubMed2000

Interactions between forage and wet corn gluten feed as sources of fiber in diets for lactating dairy cows.

Twelve early lactation Holstein cows (4 fistulated) were used in replicated 4x4 Latin squares with 4-wk periods to determine the effective neutral detergent fiber (NDF) content of wet corn gluten feed and to measure the effect of forage particle size on ruminal mat consistency and passage rate of wet corn gluten feed. Diets were 1) 23.3% NDF (17.4 percentage units of NDF from alfalfa silage), 2) diet 1 plus 11.1 additional percentage units of NDF from alfalfa silage, 3) diet 1 plus 10.7 percentage units of NDF from wet corn gluten feed, and 4) 8.6 percentage units of NDF from alfalfa silage plus 8.9 percentage units of NDF from coarsely chopped alfalfa hay and 10.7 percentage units of NDF from wet corn gluten feed. The calculated effective NDF factor for wet corn gluten feed, using change in milk fat concentration per unit change in NDF, was 0.74 compared with an assumed 1.0 for alfalfa silage. Rumination activity was measured to calculate a physically effective NDF factor for wet corn gluten feed, which was only 0.11 compared with 1.0 for alfalfa silage. Physically effective NDF also was determined for wet corn gluten feed by wet sieving; 22% of the particles were retained on the 3.35-mm screen or greater. Ruminal mat consistency increased and passage rate of wet corn gluten feed decreased with added hay. The inclusion of chopped alfalfa hay to a diet containing wet corn gluten feed increased ruminal mat consistency, rumination activity, and slowed passage rate, resulting in greater ruminal digestion of NDF from wet corn gluten feed. Depending on the response variable, the effectiveness of NDF from wet corn gluten feed varied from 0.11 to 0.74.

Animal Feed↗
PubMed2000

Effect of coarse or fine grinding on utilization of dry or ensiled corn by lactating dairy cows.

This study evaluated the effect of coarse or fine grinding of three forms of corn on the performance of lactating cows. Six diets, fed as total mixed rations, were identical except for the corn portion of the diet. Corn treatments were dry shelled corn, high moisture ensiled ear corn, and high moisture ensiled shelled corn, either coarsely or finely ground. The experimental design was a 6 x 6 Latin square with 36 cows. Eighteen cows were assigned to the six different treatments and were fed once daily. Within this group of 18 cows, six had a ruminal cannula and were used to evaluate nutrient digestibilities and ruminal fermentation. The remaining 18 cows, six of which were ruminally cannulated, were similarly assigned, except they were fed twice daily. In the group fed once daily, milk production and composition were not affected by treatment. Starch digestibility was greater with the high moisture and with the finely ground corn treatments. In addition, the high moisture ensiled corn treatments had reduced ruminal ammonia concentrations. In the group that was fed twice daily, milk production and protein yield were greatest for the finely ground high moisture ensiled shelled corn treatment. Starch utilization was improved by fine grinding. Lower ruminal ammonia concentrations were obtained with the high moisture ensiled corn treatments, and there was a tendency for reduced ammonia concentration with fine grinding. Results indicate that high moisture ensiled corn as well as fine grinding improved nitrogen and starch utilization.

Ammonia↗
PubMed2001

Maximal replacement of forage and concentrate with a new wet corn milling product for lactating dairy cows.

Three experiments were conducted to determine the maximal amount of concentrate and forage that could be replaced with a new wet corn milling product. The corn milling product contained 23.1% crude protein, 9.9% ruminally undegradable protein, 13.7% acid detergent fiber, 40.3% neutral detergent fiber, and 2.6% ether extract (% of dry matter; DM). In experiment 1, 16 Holstein cows were assigned to one of four diets in a replicated 4 x 4 Latin square design with 28-d periods. The four diets contained 54.3% forage (alfalfa:corn silages, 1:1 DM basis) with the wet corn milling product replacing 0, 50, 75, or 100% of the concentrate portion (corn and soybean meal) of the diet (DM basis). The diets containing wet corn milling product resulted in 7.8% lower DM intake, equivalent milk production (28.5 kg/d), and 13.6% greater efficiency of 4% fat-corrected milk (FCM) production than the control diet. There was no effect of diet on ruminal pH. In experiment 2, 16 Holstein cows were assigned to one of four diets in a replicated 4 x 4 Latin square design with 28-d periods. The 100% concentrate replacement diet from experiment 1 was used as control diet. For the test diets, forage was replaced with 15, 30, or 45% of the corn milling product (DM basis). Efficiency of FCM production (1.16) was not affected by diet. Rumination time was reduced for the 30 and 45% forage replacement diets, but ruminal pH was unaffected. In experiment 3, 30 Holstein cows were assigned at parturition to either a control diet (no corn milling product) or a diet containing 40% corn milling feed in place of both forage and concentrate (optimal levels from experiments 1 and 2) for 9 wk. The diet containing corn milling feed resulted in 21% greater efficiency of FCM production than the control diet. These results indicate that a new feed product based on wet corn milling ingredients has the potential to effectively replace all of the concentrate and up to 45% of the forage in the diet for lactating dairy cows.

Animal Feed↗
PubMed2003

Effects of tallow in diets based on corn silage or alfalfa silage on digestion and nutrient use by lactating dairy cows.

Six multiparous Holstein cows (average 31 days in milk; 36.3 kg/d of milk) fitted with ruminal cannulas were used in a 6 x 6 Latin square with 21-d periods to investigate the effects of diets that varied in forage source and amount of supplemental tallow. Isonitrogenous diets in a 2 x 3 factorial arrangement were based on either high corn silage (40:10 corn silage to alfalfa silage, % of dry matter) or high alfalfa silage (10:40 corn silage to alfalfa silage, % of dry matter) and contained 0, 2, or 4% tallow. Intakes of dry matter and total fatty acids were lower when cows were fed the high corn silage diet. Tallow supplementation linearly decreased dry matter intake. Milk yield was unaffected by diet; yields of milk fat and 3.5% fat-corrected milk were higher for the high alfalfa silage diet but were unaffected by tallow. Milk fat percentage was higher for the high alfalfa silage and tended to decrease when tallow was added to the high corn silage diet. Contents of trans-C18:1 isomers in milk fat were increased by high corn silage and tallow, and tended to be increased more when tallow was fed in the high corn silage diet. Ruminal pH and acetate:propionate were lower when high corn silage was fed. Ruminal acetate:propionate decreased linearly as tallow increased; the molar proportion of acetate was decreased more when tallow was added to the high corn silage diet. Ruminal liquid dilution rates were higher for the alfalfa silage diet; ruminal volume and solid passage rates were similar among diets. Total tract apparent digestibilities of dry matter, organic matter, crude protein, starch, energy, and total fatty acids were unaffected by diet. Digestibilities of neutral detergent fiber, acid detergent fiber, hemicellulose, and cellulose were lower when high corn silage was fed. The high alfalfa silage diet increased intakes of metabolizable energy and N, and increased milk energy and productive N. Tallow decreased the amount of N absorbed but had few other effects on utilization of energy or N. Tallow linearly increased concentrations of nonesterified fatty acids and cholesterol in plasma; cholesterol was increased by high alfalfa silage. Overall, forage source had more pronounced effects on production and metabolism than did tallow supplementation. Few interactions between forage source and tallow supplementation were detected except that ruminal fermentation and milk fat content were affected more negatively when tallow was fed in the high corn silage diet.

Animal Nutritional Physiological Phenomena↗
PubMed1991

Feed intake and digestion by Holstein steers fed warm or cool season grass hays with corn, dried molasses, or wheat middlings.

This study determined the effects of adding a small amount of dried molasses to supplemental corn and of supplementing with corn, wheat middlings, or corn-wheat middlings mixture on intake and digestion by Holstein steers fed warn or cool season grass hays. Eight steers (175 kg BW), in two simultaneous Latin squares, were fed, once daily, bermuda-grass (72% NDF) or ryegrass-wheat (58% NDF) hay ad libitum, alone or with approximately .05% BW of dried molasses (with 31% roughage), 5% BW of ground corn, or both. Adding dried molasses to corn decreased feed intake but did not affect digestible OM intake. Total tract digestion of fiber from bermudagrass tended to be enhanced by adding dried molasses to corn. Eight steers (193 kg BW) were used in an experiment with the same design in which similar forages were fed alone or with corn (.5% BW), wheat middlings (.63% BW), or .25% BW of corn plus .31% BW of middlings. Feed intake for both grasses was similar among supplements. Wheat middlings depressed total tract fiber digestion more than corn with both forages. Supplementation with corn depressed fiber digestion slightly more with ryegrass-wheat than with bermudagrass, but wheat middlings had a slightly greater depressing effect on fiber digestion with bermudagrass. Associative effects of mixing corn and wheat middlings in OM digestion and digestible OM intake were negative for bermudagrass and positive for ryegrass-wheat. Interaction among characteristics of basal forage and concentrate modulated feed intake and digestion by ruminants.

Animal Feed↗
PubMed1994

Electrophoretic analysis of ruminal degradability of corn proteins.

Albumin, globulin, and prolamin fractions were extracted from corn meal in water, .5 M NaCl, and 50% (vol/vol) 1-propanol and examined by SDS-PAGE and densitometric scanning to investigate fractional degradation rates of corn proteins. Several protein fractions were identified for globulins, zein prolamins, and glutelins. Ruminal degradability of individual subfractions was evaluated by suspension of corn and corn gluten meal samples in the rumen of lactating dairy cows from 0 to 72 h. Electrophoretic and densitometric analysis of protein residues revealed that the prolamin fraction zein for corn and corn gluten meal was more resistant to ruminal degradation than albumins, globulins, and glutelins. Relative rates of degradation of zein and the fraction containing albumins, globulins, and glutelins were .060, .026, and .018, .015/h for corn and corn gluten meal, respectively. Total degradabilities of corn and corn gluten meal, measured by summation of degradability of subfractional components, were 52.2 and 18.6%. Quantitative measurement of ruminally degradable subfractions and estimation of their degradation rates by electrophoretic and densitometric scanning are useful in understanding ruminal degradability of corn proteins.

Albumins↗
PubMed1997

Yield response of dairy cows fed different proportions of alfalfa silage and corn silage.

Forty-five multiparous and 29 primiparous cows were used in a complete lactation study to determine milk yield and the potential for improving N utilization by cows fed diets containing different proportions of alfalfa and corn silages. Cows were fed diets with a 50:50 forage to grain ratio. The forage portion of the diet was either all alfalfa silage, two-thirds alfalfa silage and one-third corn silage, or one-third alfalfa silage and two-thirds corn silage (dry matter basis). Treatment diets were fed to 6 ruminally cannulated cows to study dietary effects on ruminal fermentation. Diets were fed as a total mixed ration. Dry matter intake as a percentage of body weight was higher for cows fed the diet containing one-third corn silage. Mean 3.5% fat-corrected milk yield from wk 1 to 36 of lactation was 31.0, 32.9, and 31.8 kg/d for cows fed the alfalfa, one-third corn silage, and two-thirds corn silage treatment diets, respectively. For 305 d of lactation, milk yield for multiparous cows was 9593, 10,170, and 10,024 kg and for primiparous cows was 8124, 8412, and 8168 kg for cows consuming the alfalfa, one-third corn silage, and two-thirds corn silage treatment diets, respectively. Diets containing two-thirds corn silage decreased milk fat content of multiparous cows during early lactation. Ruminal NH3 concentration was lower and N excretion in the environment was reduced by 6 to 15% with the diets containing corn silage. Results suggested that corn silage should constitute one-third to two-thirds of dietary forage dry matter when fed with alfalfa silage to derive maximal benefit.

Ammonia↗
PubMed1999

Invited review: summary of steam-flaking corn or sorghum grain for lactating dairy cows.

Nineteen lactation trials (43 grain processing comparisons) are summarized, in addition to digestibility and postabsorptive metabolism studies. The net energy for lactation (NEL) of steam-flaked corn or sorghum grain is about 20% greater than the NEL for dry-rolled corn or sorghum. Based on lactational performance, steam-flaked sorghum grain is of equal value to steam-flaked corn, and steam-flaked corn is superior to steam-rolled corn. Steam-flaking of corn or sorghum compared to steam-rolling of corn or dry-rolling of corn or sorghum consistently improves milk production and milk protein yield. This result is because of a much greater proportion of dietary starch fermented in the rumen, enhanced digestibility of the smaller fraction of dietary starch reaching the small intestine, and increased total starch digestion. Steam-flaking increases cycling of urea to the gut, microbial protein flow to the small intestine, and estimated mammary uptake of amino acids. Steam-rolling compared to dry-rolling of barley or wheat did not alter total starch digestibilities in two trials, one with each grain source. Lactation studies with these processing comparisons have not been reported. Most cited studies have been with total mixed rations (TMR) and alfalfa hay as the principal forage. Additional studies are needed with lactating cows fed steam-flaked corn or sorghum in TMR containing alfalfa or corn silage. Optimal flake density of steam-processed corn or sorghum grain appears to be about 360 g/L (approximately 28 lb/bu).

Animal Nutritional Physiological Phenomena↗
PubMed1981

A comparison of the true and apparent metabolizable energy measures using corn and soybean meal samples.

This study was designed to compare the results of the true metabolizable energy (TME) and the conventional apparent metabolizable energy (AME) assays in detecting differences in the metabolizable energy content of different samples of corn and soybean meal. The samples assayed were three pairs of high and low protein soybean meals (SBM) and six corn samples of varying bushel weight. Also included in the study were two additional corn samples of a single variety of which one was a normal crop (corn ND) and the other (corn D) was obtained from plants earlier afflicted with "eye spot' fungal disease (Kabatiella zeae) so that the grain kernels did not fully mature. A somewhat larger difference was apparent in the metabolizable energy content of two of the three pairs of the high and low protein SBM using the AME assay as compared to using TME as a measure. Because of insufficient material the AME of two of the six corns that differed most in bushel weight could not be determined. The TME values for the six corns were very similar and so were the AME values for the four samples with sufficient assay material. In the case of the two corns of the same variety, corn ND showed an appreciably higher AME than corn D while the TMEs of these two samples were essentially the same. The multiplication factors for converting N-corrected AME to TME were greater for the low protein, high fiber SMB than for the high protein, low fiber samples, while the factors for corn samples were substantially smaller than those for either the high or low protein SBM. These results indicate that there may be no consistent relationship between AME and TME, although theoretically there should be a consistent relationship between these two energy measures regardless of the feedstuff assayed.

Animal Feed↗
PubMedDate not supplied

Determination of Cry9C protein in corn-based foods by enzyme-linked immunosorbent assay: interlaboratory study.

The performance of a commercially available enzyme-linked immunosorbent assay kit (Enviro-Logix) was assessed for the determination of Cry9C protein, which is produced by the genetically modified corn StarLink, in 8 types of corn-based foods (starch, refined oil, soft tortillas, tortilla chips, corn flakes, corn puffs, corn muffins, and corn bread) in an interlaboratory study involving 7 laboratories in the United States. The assay kit is a double antibody sandwich and is based on the specific interaction between antibody and antigen. The Cry9C protein analyte is sandwiched between 2 antibodies, one to capture the analyte and the other is conjugated to the enzyme, horseradish peroxidase. The enzyme uses tetramethylbenzidine/peroxide for color development. A strong acid stopping reagent is then used to change the color from blue to a stable yellow. The intensity of the color is proportional to the concentration of the Cry9C protein. In this study blind duplicates of control samples (blank material prepared from non- StarLink corn), spiked samples (blank material with the addition of Cry9C protein), and samples containing incurred analyte (products prepared with StarLink corn) were analyzed. Cry9C protein from 2 different sources was used to spike the food products. Cry9C protein produced and purified from a bacterial host was used to prepare spiked test samples at 2.72 and 6.8 ng/g. Cry9C protein from StarLink corn flour was used to prepare spiked samples at 1.97 ng/g. Average recoveries for samples spiked with corn flour Cry9C protein at 1.97 ng/g ranged from 73 to 122%, within-laboratory relative standard deviations (RSDr) ranged from 6 to 22%, and between-laboratories relative standard deviations (RSDR) ranged from 16 to 56%. Average recoveries for samples spiked with bacterial Cry9C protein at 2.72 and 6.8 ng/g ranged from 27 to 96% and from 32 to 113%, respectively; RSDr values ranged from 10 to 35% and from 7 to 38%, respectively; and the RSDR ranged from 28 to 84% and 15 to 75%, respectively. The incurred test samples were found to contain Cry9C protein at levels ranging from 0.8 to 3187 ng/g depending on the product, RSDr values ranged from 5 to 16% and RSDR values ranged from 11 to 71%. Results of the statistical analysis indicate that this method is applicable to the determination of Cry9C protein in the 8 types of collaboratively studied corn-based products containing Cry9C protein (from StarLink) at levels of > or =2 ng/g.

Bacillus thuringiensis Toxins↗
PubMed2002

[Effect of returning corn straw into soil on soil fertility].

Three-year field micro-plot experiment was conducted to study the effect of applying corn root stubble, corn straw, and the ordure of cattle fed with corn straw to improve soil fertility in northern Liaoning province. The results showed that chemical fertilizers could significantly increase the corn production, while organic fertilizers mainly improved the soil physical and chemical properties so as to increase soil fertility. In comparison with no fertilizer treatment, combination of chemical fertilizers and organic materials could increase soil organic matter by 3.06%-27.78%. The increments of soil organic matter by using different organic materials were in order of 100% corn straw > 50% corn straw > mixture of cattle ordure and soil > cattle ordure > 33% corn straw > corn root stubble. For maintaining and increasing soil organic matter, corn straw was better than mixture of cattle ordure and soil, and secondly better than cattle ordure if they contained the same carbon content. In addition, comparing with applying chemical fertilizers only, combination of chemical fertilizers and organic materials increased soil labile oxidization organic matter by 10.91%-20.67%, increased extractable humic acid by 1.43%-14.28%, raised slack/stable ratio of bonded humus by 0.07-0.19, and raised HA/FA ratio by 0.07-0.24. Meanwhile, this combination improved the soil nutrient status of N, P, and K, and the status of soil moisture and porosity, which demonstrated the increase of activity of soil organic matter and the improvement of soil fertility. So directly adding straw into soil without removing after harvest in autumn should be actively recommended, and the amount of corn straw added into soil should be 30 to 50 percent of the total production of corn straw.

Fertilizers↗
PubMed2003

Distribution patterns of MCA-coated granules aerially applied to corn fields of Southern Hungary between 2000 and 2002.

Field studies in corn (Zea mays L.) were conducted to evaluate distribution patterns of 4-methoxy-cinnamaldehyde (MCA) coated corn grits after aerial application with a Dromader fixed wing aircraft. The kairomone mimic MCA is synthetically available and a quite specific and efficient adult attractant for the invasive alien maize pest western corn rootworm (WCR) Diabrotica virgifera virgifera LeConte. Orientation disruptive properties of MCA for WCR when applied at unphysiologically high concentrations are currently under investigation. For successful implementation of the MCA disruption technique, the distribution patterns of MCA coated corn granules ('grits') in the field are important. Grits are degrained corn cobs, shredded to different sizes, coated with MCA and used as a carrier material to disseminate MCA vapors into corn fields. Granules of 10-12 mesh size were aerially applied eight times at rates ranging from 12.4 to 25.0 kg/ha. The goal is to evaluate distribution patterns of corn grits treated with MCA in three fields located at Csanadpalota, Kardoskút and Mezöhegyes in Southern Hungary between 2000 and 2002. Increasing rates reflect our attempts in finding and optimising the most even distribution of granules in the field. Field experiments were evaluated by collecting grits in 30-cm plastic saucers and by counting grits accumulated on corn plant parts. Variation in grit number per unit area and frequency of corn granule number per plant showed some transient technical application problems. Analysis of grits collected in the saucers revealed some statistical difference between the different application dates as well as differences in rates applied. Altogether grits in saucers were more evenly distributed in comparison to the grits collected on plant parts. As the corn plants age, their leaves and whorls present a smaller and smaller surface area where granules can accumulate. Altogether, however, grit distribution patterns indicate that aerial application is a viable tool for disseminating MCA in corn fields.

Acrolein↗
PubMed2000

Comparison of the effect of fish oil and corn oil on chemical-induced hepatic enzyme-altered foci in rats.

The effects of fish oil and corn oil diets on diethylnitrosamine initiation/phenobarbital promotion of hepatic enzyme-altered foci in female Sprague-Dawley rats were investigated. Groups of 12 rats were initiated with diethylnitrosamine (15 mg/kg) at 24 h of age. After weaning, they received diets containing either 13.5% fish oil plus 1. 5% corn oil or 15% corn oil for 24 weeks. Rats fed fish oil had significantly greater liver weight, relative liver weight, spleen weight, and relative spleen weight than rats fed corn oil (p < 0.05). Hepatic phospholipid fatty-acid profile was significantly affected by the type of dietary lipid. The rats fed fish oil had significantly greater hepatic phospholipid 20:5 and 22:6 than rats fed corn oil; in contrast, the rats fed corn oil had significantly greater hepatic phospholipid 18:2 and 20:4 than rats fed fish oil (p < 0.05). Rats fed fish oil had significantly lower hepatic vitamin E and PGE(2) content but significantly greater hepatic lipid peroxidation than rats fed corn oil (p < 0.05). The hepatic levels of antioxidant enzymes (GSH reductase and GST) were significantly greater in rats fed fish oil than in rats fed corn oil (p < 0.05). Except for PGST-positive foci (foci area/tissue area), all the other foci parameters (GGT-positive foci area/tissue area, GGT-positive foci no./cm(2), GGT-positive foci no./cm(3), PGST-positive foci no. /cm(2), and PGST-positive foci no./cm(3)) measured in the fish oil group were 10-30% of those in the corn oil group (p < 0.05). Analyses of Pearson correlation coefficient revealed a positive correlation between hepatic GGT- or PGST-positive foci number (no. /cm(2)) and PGE(2) content (r = 0.66, P = 0.01; r = 0.56, P = 0.02, respectively) but a negative correlation between GGT- and PGST-positive foci (no./cm(2)) and lipid peroxidation (r = -0.8, P = 0.0006; r = -0.58, P = 0.01, respectively), GSH/(GSH + GSSG) ratio (r = -0.61, P = 0.05; r = -0.4, P = 0.14, respectively), GSH reductase (r = -0.75, P = 0.002; r = -0.53, P = 0.02, respectively), and GST activities (r = -0.65, P = 0.01; r = -0.44, P = 0.07, respectively). Similar correlation between foci number (no./cm(3)) and PGE(2), lipid peroxidation, GSH/(GSH + GSSG) ratio, GSH reductase, and GST activities were obtained. The results of this study show that dietary fish oil significantly inhibited hepatic enzyme-altered foci formation compared with corn oil in rats. These results suggest that the possible mechanisms involved in this process are the stimulation of hepatic detoxification system, changes in membrane composition, inhibition of PGE(2) synthesis, the enhancement of GSH-related antioxidant capacity, and the enhancement of lipid peroxidation by fish oil.

Animals↗