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PubMed1979

Cadmium concentration and distribution in corn (Zea mays L.) grown on a calcareous soil for three years after three annual sludge applications.

The disposal of digested sewage sludge on crop-producing land appeals to municipalities as an option but may pose a hazard to human and animal health if the plant material contains elevated levels of some heavy metals. This paper reports the levels of cadmium in corn grain and stover for six years -- three years with sludge applied annually and for three years after sludge applications were terminated. The cadmium concentration in corn grain from the sixth year was similar to values found in corn grown on non-sludged plots. In corn stover from treated plots the cadmium concentration was greater than from untreated plots. Our study indicated that phytotoxic levels of cadmium did not exist even though elevated levels occurred in the corn stover.

Cadmium↗
PubMed2001

Genetically modified feeds in animal nutrition. 1st communication: Bacillus thuringiensis (Bt) corn in poultry, pig and ruminant nutrition.

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.

Animal Feed↗
PubMed1994

Voluntary intake and digestibility by mature beef cattle and Holstein steer calves consuming alfalfa or orchardgrass hay supplemented with soybean oil and(or) corn.

Effects and interactions of corn and soybean oil supplementation and forage source on feed intake and digestibility by mature and growing cattle were determined. Eight mature beef cattle (571 +/- 17 kg initial body weight) were used in two simultaneous 4 x 4 Latin squares. Cattle in each square consumed long-stemmed alfalfa (AL; 16% crude protein, 54% neutral detergent fibre and 6.1% acid detergent lignin) or orchardgrass (OR; 11% crude protein, 71% neutral detergent fibre and 9.4% acid detergent lignin) hay ad libitum for 15 d followed by 6 d of restricted consumption (85% of ad libitum). Supplement treatments were Control, ground corn (C; 0.5% body weight), soybean oil (O; 0.125% body weight), or C + O. Total ad libitum dry matter (DM) intake was greater for AL than for OR (P < 0.05) and with than without C (P < 0.05), and a corn x soybean oil interaction occurred (P = 0.07; 11.8, 14.0, 13.6, 14.2, 8.4, 10.7, 9.3 and 10.3 kg/d); total tract neutral detergent fibre (NDF) digestibility was 66.0, 67.7, 65.8, 68.8, 52.5, 50.6, 55.1 and 59.4% for AL, AL - C, AL - O, AL - C + O, OR, OR - C, OR - O, and OR - C + O, respectively (SE 2.46). Eight Holstein steer calves (83 +/- 5 and 131 +/- 11 kg initial and final body weight, respectively) were subjected to the same dietary treatments, except for higher levels of C (1.0% body weight) and O (0.25% body weight) and periods with 21 d of ad libitum forage intake. Total DM intake was greater (P = 0.06) for AL than for OR, increased (P < 0.05) by C, and decreased (P < 0.05) by O (3.92, 4.17, 3.51, 4.00, 2.53, 2.90, 2.09 and 2.51 kg/d), and total tract NDF digestibility was affected by forage source (P < 0.05) and a corn x soybean oil interaction (P = 0.08; 58.8, 56.9, 60.1, 56.0, 41.9, 44.5, 45.8 and 40.1% for AL, AL - C, AL - O, AL - C + O, OR, OR - C, OR - O and OR - C + O, respectively). In conclusion, effects of supplementation with corn and (or) soybean oil on feed intake and digestibility were similar for AL and OR, which differed in voluntary intake and digestibility, and animal characteristics such as stage of maturity may have influenced effects of soybean oil on feed intake.

Aging↗
PubMed1998

[The effect of size reduction of corn silage on feed intake, milk production and milk composition of cows].

In three experiments (E1, E2, E3) maize silage of different physical structure and of different stage of maturity at harvest were fed to 24 (E1), 36 (E2) or 28 (E3) dairy cows. The cows were fed individually over an experimental period of five or six weeks. The maize silages had a mean DM content of 28% (E1), 32% (E2) or 36% (E3). At the stage of harvest, the stovers and the cobs had a mean DM content of < 22% (E1, E2) or 27% (E3), 40% (E1), 46% (E2) or 57% (E3), respectively. The maize was harvested with a chopping length of 4 and 8 mm (E1, E3) and of 6 and 8 mm (E2), without corn cracking (E1) or with and without corn cracking (E2, E3). The daily feed ration consisted of ad libitum offered maize silage, 1.7 kg DM hay, soya bean meal (E2, E3) and concentrate. The different chopping length of 4 mm, 6 mm or 8 mm had no effect on the maize silage intake in E1 and E2. In E3 the daily maize silage intake increased by about 1.2 kg DM per cow at a chopping length of 4 mm in comparison to 8 mm, whereas only the treatment with the combination of 4 mm chopping length and corn cracking showed a significant increase in DMI. The corn cracking improved the milk yield significantly (E2) or in a tendency (E3) at 2.0 kg (E2) or at 1.6 kg (E2), while the variation of chopping length had no effect on milk yield. The different physical structure did not influence the milk fat content with mean values of 4.65% (E1), 4.15% (E2) and 4.10% (E3), respectively. The milk protein content decreased in E2 feeding maize silage with a chopping length of 8 mm and corn cracking; but in E1 and E3 no effect was seen on protein content with mean values of 3.66% (E1) or 3.51% (E2).

Animals↗
PubMed2002

Compressional characteristics of native and pregelatinized forms of sorghum, plantain, and corn starches and the mechanical properties of their tablets.

A study was made of the compressional characteristics of native and pregelatinized forms of sorghum, plantain, and corn starches and the mechanical properties of their tablets. Compressional characteristics were analyzed using density measurements and the Heckel and Kawakita plots. Pregelatinized starches exhibited more densification than native starches during die filling and at low pressures. The ranking for the mean yield pressure (Py) values for the starches was plantain < corn < sorghum, with the pregelatinized starches having lower values than the native starches. The ranking for the values of another pressure term, Pk--an inverse measure of plasticity, was corn < plantain < sorghum, but with the native starches having the lower values. For the tablets, the ranking for values of tensile strength (T) was corn > plantain > sorghum, while the ranking for the brittle fracture index (BFI) was plantain > corn > sorghum. Tablets made from pregelatinized starches had lower T and BFI values than those made from native starches. The results suggest that pregelatinization of the starches facilitated faster onset of plastic deformation but reduced the amount of plastic deformation which occurred during the compression process.

Compressive Strength↗
PubMed2001

Corn starches as film formers in aqueous-based film coating.

The purpose of this study was to evaluate the film formation ability and mechanical stress-strain properties of aqueous native corn starches, using free films and film coatings applied to tablets. Free films were prepared from high-amylose corn (Hylon VII), corn and waxy corn starches, using sorbitol and glycerol as plasticizers. The tablets and pellets were film-coated using an air-suspension coater, and characterized with respect to the film coating surface topography, cross-sectional structure and thickness (SEM), and dissolution in vitro. The amylose content of the starch film formers affected both the tensile strength and the elongation. The elongations were under 5% for even the plasticized starches, and in most cases, no plasticization effect was seen by either of the plasticizers. Dissolution of native corn starch film-coated tablets (weight gain 1%) did not differ from uncoated ones. A notable delay in dissolution of the drug was found by increasing Hylon VII film coating thickness, suggesting controlled-release characteristics.

Amylose↗
PubMed1953

Nutrition of the European corn borer, Pyrausta nubilalis (HBN). III. An unidentified dietary factor required for larval growth.

1. The European corn borer larva has been shown to require a dietary source of one or more unidentified factors contained in corn leaves, grass juice concentrate, and certain other plant materials. The required factor or factors has been termed the corn leaf factor. 2. The corn leaf factor does not appear to be identical with any of the known B vitamins, or with ascorbic acid, sodium nucleate, citrovorum factor, or carnitine. 3. The corn leaf factor is heat-stable, acid-stable, water-soluble, and dialyzable.

Animals↗
PubMed2003

In-field labeling of western corn rootworm adults (Coleoptera: Chrysomelidae) with rubidium.

Field and laboratory studies were conducted in 2000 and 2001 to determine the feasibility of mass marking western corn rootworm adults, Diabrotica virgifera virgifera LeConte, with RbCl in the field. Results showed that application of rubidium (Rb) in solution to both the soil (1 g Rb/plant) and whorl (1 g Rb/plant) of corn plants was optimal for labeling western corn rootworm adults during larval development. Development of larvae on Rb-enriched corn with this technique did not significantly influence adult dry weight or survival. Rb was also highly mobile in the plant. Application of Rb to both the soil and the whorl resulted in median Rb concentrations in the roots (5,860 ppm) that were 150-fold greater than concentrations in untreated roots (38 ppm) 5 wk after treatment. Additionally, at least 90% of the beetles that emerged during the first 3 wk were labeled above the baseline Rb concentration (5 ppm dry weight) determined from untreated beetles. Because emergence was 72% complete at this time, a significant proportion of the population had been labeled. Results from laboratory experiments showed that labeled beetles remained distinguishable from unlabeled beetles for up to 4 d postemergence. The ability to efficiently label large numbers of beetles under field conditions and for a defined period with virtually no disruption of the population provides an unparalleled opportunity to conduct mark-recapture experiments for quantifying the short-range, intrafield movement of adult corn rootworms.

Animals↗
PubMed2005

Node-injury scale to evaluate root injury by corn rootworms (Coleoptera: Chrysomelidae).

Corn rootworm larval feeding on corn roots can significantly reduce grain yield by interfering with photosynthetic rates, limiting the uptake of water and nutrients, and by increasing the plant's susceptibility to lodging. Of the techniques developed to measure the efficacy of corn rootworm larval control tactics, root damage ratings have generally been adopted as the standard because sampling roots is relatively efficient. Historically, the primary scales used for scoring root injury from corn rootworm larval feeding have been the 1-6 and 1-9 scales. A critical deficiency of those scales, however, is that each increase in a root-rating score does not reflect a linear increase in the actual amount of injury to the root system. This results in injury scores that are expressed qualitatively. We developed the node-injury scale to more accurately quantify corn rootworm larval injury based on the proportion of nodal roots that contain feeding injury. With the node-injury scale, the relationship between the numerical scale and the amount of root injury is linear and intuitive. In this article, we describe the node-injury scale, discuss sampling issues to consider when using the scale, and suggest the minimum node-injury score that causes economic damage under varying degrees of environmental stress.

Agriculture↗
PubMed1978

Effects of an essential fatty acid deficiency, pair-feeding and level of dietary corn oil on the hypothalamic-pituitary-gonadal axis and other physiological parameters in the male chicken.

Two studies were conducted to observe the effects of an essential fatty acid (EFA) deficiency, added dietary corn oil and pair-feeding on growth, reproduction and other physiological parameters in the mature cockerel. A purified, linoleic acid (LA)-deficient diet (0.01% LA), or additions of 5% (3.01% LA) or 15% (9.04% LA) corn oil, were fed ad libitum from hatching through 24 weeks of age. Reductions in growth, feed consumption, and comb, and testes size, incomplete spermatogenesis, increased tissue eicosatrienoic acid (20: 3 omega 9) and changes in weights of selected internal organs were observed in deficient cockerels. Total pituitary gonadotropic activity was measured by two bioassay procedures and blood luteinizing hormone was measured by radioimmunoassay. By maturity both of these parameters were significantly reduced in deficient chickens. When these chickens were fed diets with 5% or 15% corn oil under pair-feeding or ad libitum conditions from 20 to 24 weeks, the reduced growth, comb and testes size and gonadotropin metabolism appeared to be caused by depressions in appetite and energy intake rather than EFA per se. The degenerate testicular histology of the 20-week old deficient cockerels, while responding fully to the ad libitum intake of the diets containing corn oil, showed only partial rehabilitation of spermatogenesis when diets with either 5% or 15% corn oil were pair-fed. In general, increasing the level of dietary fat from 5% to 15% did not cause many physiological changes.

Animals↗
PubMed1988

Immature corn as a source of niacin for rats.

The variability in the concentration and biological availability of niacin in corn was investigated. Plots of both sweet and field corn were harvested at different stages. In rat growth assays for available niacin, grains harvested at the immature, "milky" stage and then dried gave values of 88 and 74 micrograms/g, respectively. These values were in contrast to the low growth assay values of 18 and 16 micrograms/g for grain harvested at maturity, and even higher than the value of approximately 56 micrograms/g obtained for each immature corn in both the Association of Official Analytical Chemists procedure of chemical analysis and a standard microbiological procedure. However, when the milky grains were precooked at neutral pH, the values from these procedures were higher and agreed with the biological assay results. It is suggested that, during the initial alkaline digestion used for these two procedures, a proportion of the niacin in NAD, the major form of niacin in milky corn, degrades. However, when the materials are first cooked at neutral pH, nicotinamide is released without loss, and the pyridine ring is then stable. The traditional American Indian practice of roasting and drying "green corn" apparently provided a valuable source of niacin.

Animals↗
PubMed1993

Starch bioavailability in arepas made from ordinary or high amylose corn: concentration and gastrointestinal fate of resistant starch in rats.

The purpose of the present investigation was to study the importance of the amylose/amylopectin ratio for the content and gastrointestinal fate of resistant starch in a realistic composite starchy food. Corn-based breads (arepas) from dent corn (25% amylose) and from high amylose corn (70% amylose) were used as test products. Resistant starch concentration was evaluated in vitro and in vivo using rats treated with an antibiotic drug (Nebacitin) to suppress hindgut fermentation. Experiments in rats with intact hindgut microflora allowed determination of resistant starch fermentability. The small intestinal digestibility of starch in dent corn arepas was close to 96% (total starch basis), whereas the starch in high amylose arepas was poorly digested (approximately 68%, total starch basis), as calculated from the fecal recovery of resistant starch in Nebacitin-treated animals. The main resistant starch fraction required solubilization in alkali to render it available to the analytical amylases (nonhydrated fraction). The total amount of resistant starch as well as the nonhydrated starch fraction delivered to the hindgut could be accurately predicted from analysis of starch remnants in an enzymatic gravimetric dietary fiber residue. Resistant starch present in dent corn arepas was fermented approximately 63%, whereas the fermentability of resistant starch from the high amylose product was remarkably low (< 11%).

Amylopectin↗
PubMed2000

Nutritional evaluation of low phytate and high protein corns.

Three chick experiments and two cecectomized rooster experiments were conducted to determine P bioavailability and amino acid (AA) digestibility in two low phytate corns (LP), a high protein corn (HP), and a corn containing both low phytate and high protein content (HP/LP) compared with conventional corn (CONV). From 8 to 20 or 21 d of age, 1-wk-old New Hampshire x Columbian chicks were fed a cornstarch-dextrose-soybean meal (SBM) basal diet containing 0.10% available P or the basal diet supplemented with two concentrations of P (0.05 or 0.06% and 0.10 or 0.12%) from KH2PO4 or two concentrations of the corns (20 or 21% and 40 or 42%). Bioavailability of P based on tibia bone ash was much higher for LP than for CONV; values ranged from 21 to 40% for CONV and from 59 to 95% for LP. Digestibility of AA in cecectomized roosters indicated no significant differences (P > 0.05) between CONV and HP in the first rooster experiment. Digestibilities of eight AA, including lysine, methionine, and arginine, in LP and HP/LP were higher (P < 0.05) than those in CONV in the second rooster experiment. The results of this study indicated that the P in LP was two to three times more bioavailable than the P in CONV and that the digestibilities of AA in HP/LP were equal to or higher than those in CONV.

Amino Acids↗
PubMed2002

Effects of age on development of digestive organs and performance of chicks fed a corn-soybean meal versus a crystalline amino acid diet.

Changes in growth performance and physical and morphological development of the digestive organs were examined in chicks fed a crystalline amino acid (AA) diet compared to chicks fed a corn-soybean meal (SBM) diet. Six pens of eight New Hampshire x Columbian male chicks were assigned to one of three dietary regimens: (1) corn-SBM diet from 0 to 21 d of age; (2) cornstarch-crystalline AA diet from 0 to 21 d of age; and (3) corn-SBM diet from 0 to 7 d of age followed by the crystalline AA diet from 8 to 21 d of age. Weight gain was significantly reduced by feeding a crystalline AA diet from 0 to 21 or 8 to 21 d of age. Feeding a crystalline AA diet for the first 7 d of age depressed absolute weight of the small intestine, pancreas, liver, gizzard, and proven-triculus, and continual feeding through 21 d of age further depressed growth of these organs compared with birds fed a corn-SBM diet for 21 d. When expressing organ weight on a relative basis (g/100 g of BW), reductions were observed at 7 d of age due to feeding a crystalline AA diet but not at 21 d of age. Feeding a crystalline AA diet for the first 7 or 21 d of age depressed intestinal villi height and crypt depth. However, chicks fed the crystalline AA diet only from 8 to 21 d of age had further depressed villi height and crypt depth but greater villi width compared with chicks fed the crystalline AA or corn-SBM diet continually from 0 to 21 d of age. These results indicate that the reduced growth of chicks fed a crystalline AA diet is due in part to slower growth and development of the gastrointestinal tract.

Aging↗
PubMed1993

Purification and Characterization of Porin from Corn (Zea mays L.) Mitochondria.

Mitochondrial porin from corn (Zea mays L. B 73) shoots was solubilized with lauryl(dimethyl)-amine oxide and purified by chromatography on a hydroxyapatite:celite column. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the purified protein had an apparent molecular mass of 35 kD. When reconstituted in planar lipid bilayer membranes the porin formed ion-permeable channels with single-channel conductance of 2.0 and 4.0 nanosiemens in 1 M KCl. At low transmembrane voltages corn porin had the properties of a general diffusion pore with an estimated effective diameter of 1.6 nm and a small selectivity for anions over cations. The primary structure of corn porin seems to be quite different from that of other mitochondrial porins, because it did not cross-react with monoclonal antibodies against human porin and with polyclonal antibodies against yeast porin. Furthermore, the peptide maps of corn and bovine heart porins were very different. A sequence of 21 amino acids obtained by Edman degradation of peptides generated by porin proteolysis with Staphylococcus aureus V8 protease did not show any significant homology with known sequences of mitochondrial porins. Results of our investigation suggest that corn porin possesses functional properties similar to those of other mitochondrial porins, despite major structural differences.

Journal Article↗
PubMed1979

In Vitro Synthesis of a Precursor to the Methionine-rich Polypeptide of the Zein Fraction of Corn.

The messenger ribonucleic acid fraction isolated from a protein bodyenriched fraction of developing corn (Zea mays L.) endosperm stimulated the incorporation of radioactive amino acids into at least five polypeptides when added to a wheat germ extract capable of protein synthesis. Of these, the two major polypeptides formed with messenger from freshly frozen corn were identified as precursors to zein A and B, the two major polypeptides of the prolamine fraction of corn meal (21,600 and 19,600 molecular weight). The identification was based on the relative incorporations of radioactive leucine, lysine, and methionine, and the susceptibility of the zein A precursor, but not the zein B precursor to cleavage with cyanogen bromide. Using extracts from stored frozen corn, a third polypeptide of 14,500 molecular weight was identified as a major in vitro product. It was preferentially labeled with methionine and slightly larger than a similar peptide in the zein fraction of corn meal. Two other polypeptides of still lower molecular weight could be detected above the background of probably incomplete polypeptides.

Journal Article↗
PubMed1981

Subcellular localization of proteases in wheat and corn mesophyll protoplasts.

Mesophyll protoplasts were isolated from the leaves of wheat and corn seedlings. After purification the protoplasts were judged to be free of contaminating proteases in the isolation enzymes based on specific activity of the proteases in comparison to leaf tissue and their response to inhibitors that "differentiated" between leaf and isolation enzyme proteases. Wheat protoplasts showed rates of photosynthesis of 95 to 100 micromoles O(2) per milligram chlorophyll per hour, while corn exhibited rates of 35 to 85 micromoles O(2) per milligram chlorophyll per hour, indicating the intactness of the chloroplasts within the protoplasts. These chloroplasts were isolated from the protoplasts using the procedure of Robinson and Walker (1979 Arch Biochem Biophys 196: 319-323). Yields of 91 and 82% intact chloroplasts were obtained from wheat and corn, respectively, based on the distribution of ribulose bisphosphate carboxylase in wheat and NADP-malate dehydrogenase in corn. Vacuoles were obtained from the protoplasts using a modification of the techniques of Wagner and Siegelman (1975 Science 190: 1298-1299) and Saunders (1979 Plant Physiol 64: 74-78). The vacuoles were at least 98% free of protoplast contamination as determined by assaying for "marker" enzymes of chloroplasts, mitochondria, and endoplasmic reticulum. Assuming one vacuole per protoplast, the vacuoles contained 4% of the soluble protein of the protoplasts in wheat and 8% in corn. All the proteolytic activity associated with the degradation of ribulose bisphosphate carboxylase in the protoplasts could be accounted for by that localized within the vacuoles. Although the isolated chloroplasts always retained about 13% of the proteolytic activity of the protoplasts, this could be accounted for by that which became associated with the chloroplasts during their isolation.

Journal Article↗
PubMed1986

Detection of Xylem Cavitation in Corn under Field Conditions.

We report the detection of cavitation events in corn (Zea mays) plants growing under field conditions in Greeley, CO. To our knowledge this study reports the first successful attempt to monitor continuously for long periods the cavitation events of a crop plant using acoustic detection techniques. Cavitation events occur in corn plants using acoustic detection techniques. Cavitation events occur in corn plants irrigated daily when the xylem pressure potentials fall below about -1.0 megapascals. In unirrigated corn we estimate that approximately half of all vessels cavitate on any one day when xylem pressure potentials fall below about -1.8 megapascals. We postulate that root pressure developed every night in irrigated and unirrigated corn is adequate to rejoin cavitated water columns.

Journal Article↗