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PubMed1977

Improved procedure for quantitative determination of aflatoxins in corn and wet milled corn products.

Aflatoxins are extracted from the sample by high-speed blending with aqueous acetone, purified with ammonium sulfate, and partitioned into benzene. The benzene extract is purified on a silica gel-alumina column by washing with benzene-acetic acid and ether-hexane, and eluted with methylene chloride-acetone. The eluate is evaporated, redissolved in benzene-acetonitrile, and spotted on a thin layer chromatographic plate for resolution and quantitative determination against standards.

Aflatoxins↗

PubMed1994

NTP Comparative Toxicology Studies of Corn Oil, Safflower Oil, and Tricaprylin (CAS Nos. 8001-30-7, 8001-23-8, and 538-23-8) in Male F344/N Rats as Vehicles for Gavage.

The types and levels of fats in the diet are known to affect the incidence of certain neoplasms in humans and rodents. In long-term toxicity and carcinogenicity studies in rodents, the level of dietary fat is altered by using oil as a vehicle to administer unpalatable or volatile chemicals. Control male rats receiving a corn oil vehicle have a higher incidence of pancreatic proliferative lesions and a lower incidence of mononuclear cell leukemia than untreated control males. Therefore, the National Toxicology Program (NTP) designed studies to evaluate the role of several oils in altering cancer rates in male rats. The NTP study reported here was part of a larger program that included cooperative agreements with Dartmouth Medical School, Northwestern Medical School, and the University of Missouri. The program was designed to study the mechanisms by which corn oil induces pancreatic cancer. To evaluate corn oil as well as two other gavage vehicles for potential toxicity, corn oil, safflower oil, and tricaprylin were administered by gavage to male F344/N rats for 2 years. The rats that received corn oil were also made available to the university investigators for study of the corn oil-induced pancreatic lesions. Each vehicle was administered by gavage at volumes of 2.5, 5, or 10 mL/kg body weight once daily for 5 days per week. In the corn oil study, a control of 10 mL saline/kg was also included. To evaluate the potential role of corn oil in promoting a pancreatic proliferative effect, 500 mg dichloromethane/kg body weight was administered in 2.5, 5, or 10 mL corn oil/kg body weight for 2 years to male F344/N rats. Dichloromethane was chosen because the chemical appeared to cause pancreatic proliferative lesions when administered by gavage in a corn oil vehicle but not when the exposure was by inhalation. In each of these studies, the term "dose" refers to the volume of gavage vehicle administered. 2-YEAR STUDIES OF CORN OIL, SAFFLOWER OIL, AND TRICAPRYLIN: Survival and Body Weights: Two-year survival was increased in male rats receiving corn oil (untreated control, 26/50; saline control, 32/50; 2.5 mL/kg, 33/50; 5 mL/kg, 38/50; 10 mL/kg, 40/50) primarily due to a dose-related decreased incidence of mononuclear cell leukemia. The mean body weights of all dosed groups were at least 5% higher than those of the untreated and saline controls by week 48, but the mean body weights of groups receiving 2.5 or 5 mL corn oil/kg decreased during the final weeks of the study (after week 89) and were similar to those of the controls at the end of the study. Two-year survival was slightly increased in male rats receiving safflower oil relative to that of the controls (untreated control, 30/50; 2.5 mL/kg, 33/50; 5 mL/kg, 40/50; 10 mL/kg, 36/50). The mean body weight of male rats receiving 10 mL safflower oil/kg was at least 5% greater than that of the controls after week 45 and was 16% greater by the end of the study. Two-year survival of high-dose tricaprylin males was lower than that of the controls (untreated control, 31/50; 2.5 mL/kg, 30/50; 5 mL/kg, 31/50; 10 mL/kg, 23/53) due to moribund kills and deaths that appeared to be related to toxicity. The mean body weight of the high-dose group was lower than that of the controls throughout the study, although the difference was less than 5% after week 61. Pathology Findings: In the corn oil study, there were significant dose-related increased incidences of pancreatic exocrine hyperplasia and adenoma (hyperplasia: 8/50, 28/47, 28/50, 35/50; adenoma: 1/50, 8/47, 10/50, 23/50; carcinoma: 0/50, 0/47, 1/50, 0/50 in the untreated control, 2.5, 5, and 10 mL/kg groups, respectively). The incidence and severity of nephropathy decreased with dose (incidence [mean severity grade]: 47/50 [2.1], 43/48 [1.8], 45/50 [1.4], 40/49 [1.2]). The incidences of pheochromocytomas (benign, malignant, or complex) of the adrenal medulla were also decreased in dosed rats (23/49, 21/50, 5/50, 9/50). The incidence of mononuclear cell leukemia was significantly decreased in rats dosed with corn oil (27/50, 16/50, 11h corn oil (27/50, 16/50, 11/50, 7/50). In rats receiving safflower oil, the incidences of pancreatic exocrine hyperplasia and adenoma increased significantly with dose (hyperplasia: 8/50, 14/50, 29/49, 30/50; adenoma: 1/50, 7/50,15/49, 28/50; carcinoma: 0/50, 0/50, 0/49, 1/50 in the untreated control, 2.5, 5, and 10 mL/kg groups, respectively). There was a decrease in the severity, but not in the incidence, of nephropathy, a common lesion in aging F344/N rats (incidence [mean severity grade]: 49/50 [2.0], 50/50 [1.8], 47/50 [1.1], 49/49 [1.1]). There were decreased incidences of mononuclear cell leukemia (33/50, 19/50, 18/50, 7/51). In the tricaprylin study, there were significant dose-related increased incidences of pancreatic exocrine hyperplasia and adenoma (hyperplasia: 8/49, 9/49, 18/49, 28/50; adenoma: 2/49, 6/49,13/49,18/50 in the untreated control, 2.5, 5, and 10 mL/kg groups, respectively). The incidence of proliferative lesions of the forestomach increased significantly with dose (basal cell hyperplasia: 4/50, 7/50, 12/49, 21/52; squamous cell papilloma: 0/50, 0/50, 3/50, 10/53). The incidence of nephropathy was significantly decreased in high-dose rats, and the severity of nephropathy decreased with dose (incidence [mean severity grade]: 46/50 [2.0], 42/50 [1.5], 45/50 [1.7], 27/49 [0.9]). In high-dose rats, the incidence of mononuclear cell leukemia was decreased (23/50, 28/50, 22/50, 9/53). 2-YEAR STUDY OF DICHLOROMETHANE IN CORN OIL: Survival and Body Weights: Two-year survival increased slightly with dose in the three groups receiving 500 mg dichloromethane/kg in 2.5, 5, or 10 mL corn oil/kg (23/50, 28/50, 31/50) due to a dose-related decrease in the incidence of mononuclear cell leukemia. The rats receiving 500 mg dichloromethane/kg without corn oil were sacrificed within the first 3 weeks of the study due to the severe toxicity of dichloromethane. The final mean body weight of the high-dose rats was greater than the final mean body weights of groups receiving dichloromethane in 2.5 or 5 mL corn oil/kg. Pathology Findings: There was a dose-related increase in the incidence of pancreatic proliferative exocrine lesions in rats receiving dichloromethane in 2.5, 5, and 10 mL corn oil/kg (hyperplasia: 28/50, 38/50, 44/50; adenoma: 9/50,19/50, 41/50; carcinoma: 0/50,1/50, 3/50). The incidences of pancreatic exocrine hyperplasia and adenoma in rats receiving dichloromethane in 5 or 10 mL, but not 2.5 mL, corn oil were increased compared to the incidences in rats receiving comparable volumes of corn oil alone (hyperplasia: 2.5 mL, 28/47; 5 mL, 28/50;10 mL, 35/50; adenoma: 8/47,10/50, 23/50; carcinoma: 0/47,1/50, 0/50). There were significantly increased incidences of pituitary gland pars distalis adenoma in rats receiving dichloromethane in corn oil (20/50, 18/49, 16/49) when compared to those in rats receiving comparable volumes of corn oil alone (10/50, 6/49, 7/50). The incidence of mammary gland adenoma and fibroadenoma (combined) was significantly increased in rats receiving dichloromethane in 10 mL corn oil/kg (7/50) when compared to rats receiving dichloromethane in 2.5 mL corn oil/kg (1/50), but was not significantly increased when compared to the group receiving 10 mL of corn oil alone (3/50). The incidences of mammary gland adenoma and fibroadenoma (combined) were 7/50 for the untreated safflower oil controls and 6/50 for the untreated tricaprylin controls. The incidence of mononuclear cell leukemia decreased in the group receiving dichloromethane in 10 mL corn oil/kg (13/50,14/50, 5/50). GENETIC TOXICOLOGY: Neither safflower oil nor corn oil was mutagenic in Salmonella typhimurium strains TA97, TA98, TA100, or TA1535, with or without S9. Tricaprylin, in contrast, was mutagenic in strain TA1535 with, but not without, S9. Tricaprylin did not induce mutations in strains TA97, TA98, or TA100, with or without S9. SUMMARY: These studies were designed to evaluate the effects of various concentrations of an oil very high in polyunsaturated fat (safflower oil), an oil containing high levels of polyunsaturated and monounsaturated fats (corn oil), and an oil containing saturated medium-chain fatty acids (tricaprylin) on the incidence and pattern of neoplasms in the F344/N rat. In addition, safflower oil and tricaprylin were evaluated as replacements for the corn oil vehicle. These studies demonstrate that safflower oil and tricaprylin do not offer significant advantages over corn oil as a gavage vehicle in long-term rodent studies. Corn oil, safflower oil, and tricaprylin each caused hyperplasia and adenoma of the exocrine pancreas, decreased incidences of mononuclear cell leukemia, and reduced incidences or severity of nephropathy in male F344/N rats. There was an increased incidence of squamous cell papillomas of the forestomach in F344/N rats receiving 10 mL tricaprylin/kg. Further, the use of corn oil as a gavage vehicle may have a confounding effect on the interpretation of chemical-induced proliferative lesions of the exocrine pancreas and mononuclear cell leukemia in male F344/N rats. Synonyms: Corn Oil - Maize oil, Maydol Tricaprylin - Trioctanoin; 1,2,3-trioctanoyl glycerol; Glycerol trioctanoate

Journal Article↗

PubMed2005

Effect of cattle age, forage level, and corn processing on diet digestibility and feedlot performance.

Three experiments were conducted to determine the effects of cattle age and dietary forage level on the utilization of corn fed whole or ground to feedlot cattle. In Exp. 1, 16 steers were used to investigate the effects of cattle age and corn processing on diet digestibility. Two cattle age categories were evaluated (weanling [254 +/- 20 kg BW] and yearling [477 +/- 29 kg BW]; eight steers per group), and corn was fed either ground or whole to each cattle age category. Cattle age and corn processing did not affect (P > 0.10) diet digestibility of DM, OM, starch, CP, NDF or ADF, and no interactions (P > 0.10) between these two factors were detected. In Exp. 2, the effects of forage level and corn processing on feedlot performance and carcass characteristics were evaluated. One hundred eighty steers (310 +/- 40 kg BW) were allotted to 24 pens, and were fed one of the following diets: high-forage (18.2% corn silage) cracked corn (HFCC); high-forage shifting corn (whole corn for the first half of the trial, then cracked corn until harvest; HFSC); high-forage whole corn (HFWC); low-forage (5.2% corn silage) cracked corn (LFCC); low-forage shifting corn (LFSC); and low-forage whole corn (LFWC). For the high-forage diets, steers fed cracked corn had 7% greater DMI than those fed whole corn, whereas for the low-forage diets, grain processing did not affect DMI (interaction; P = 0.02). No interactions (P > 0.10) between forage level and corn processing were found for ADG and G:F. Total trial ADG and G:F, and percentage of carcasses grading USDA Choice, and carcass yield grade were not affected (P > 0.10) by corn processing. Cattle with fewer days on feed grew faster and more efficiently when cracked corn was fed, whereas cattle with longer days on feed had greater ADG and G:F when corn was fed whole (interaction; P < 0.10). In Exp. 3, the effects of forage level and corn processing on diet digestibility were evaluated. The high-forage cracked corn, high-forage whole corn, low-forage cracked corn, and low-forage whole corn diets used in Exp. 2 were fed to 16 steers (350 +/- 27 kg BW) in a digestion trial. No interactions (P > 0.10) between forage level and corn processing were detected for starch digestibility. Forage level and corn processing (grinding) did not affect (P > 0.10) diet DM, OM, starch, CP, and NDF digestibility. Processing corn did not provide additional benefits to feedlot cattle performance under these experimental conditions.

Age Factors↗

PubMed2002

The nutritional value of degermed, dehulled corn for pigs and its impact on the gastrointestinal tract and nutrient excretion.

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.

Animal Feed↗

PubMed2005

Comparison of yellow dent and NutriDense corn hybrids in swine diets.

Two experiments were conducted to verify the feeding value of NutriDense (ND) and Nutri-Dense Low-Phytate (NDLP) corn (Exseed Genetics LLC, BASF Plant Science, Research Triangle Park, NC) relative to that of yellow dent (YD) corn in swine diets. NutriDense corn is a high-protein, high-oil variety, and NDLP is a high-protein, high-oil, low-phytate variety. In Exp. 1, 315 nursery pigs that initially weighed 15.2 kg were used in a 21-d growth assay. Dietary treatments were arranged in a 3 x 3 factorial; main effects were corn source (YD, ND, and NDLP) and added fat (0, 3, or 6%, as-fed basis). Diets were formulated to contain 3.83 g of lysine/Mcal using calculated nutrient values. There were no corn source x fat interactions observed. Pigs fed YD, ND, and NDLP had ADG of 750, 734, and 738 g/d and G:F of 0.64, 0.66, and 0.65, respectively. No differences (P > 0.10) in ADG were observed among the three corn sources; however, pigs fed diets containing either ND or NDLP corn had decreased ADFI (P < 0.02) and improved G:F (P < 0.05) compared with pigs fed diets containing YD corn. Increasing dietary fat increased ADG (727, 746, and 748 g/d; linear, P < 0.04) and G:F (0.62, 0.66, and 0.68; linear, P < 0.01) and decreased ADFI (linear, P < 0.01). Using the NRC (1998) value for ME in YD corn, we calculated the energy value for ND and NDLP based on G:F differences compared with pigs fed YD corn. These data indicated the ME values for ND and NDLP corn are 4.5 and 2.5% greater (3,575 and 3,505 Kcal/kg), respectively, than for YD corn (3,420 Kcal/kg). In Exp. 2, 1,144 gilts (initial BW = 50.1 kg) were used in a commercial research facility to evaluate the effects of corn source (ND and YD) and added fat (0, 3, or 6%, as-fed basis) in a 2 x 3 factorial on pig performance and carcass traits. There was a corn source x fat interaction for ADFI and G:F. Increasing added fat resulted in greater changes in ADFI and G:F in pigs fed YD corn diets compared with those fed ND corn. Feeding ND corn increased ADG (main effect, P < 0.04), and greater percentages of added fat increased ADG (main effect; linear, P < 0.01). Results of Exp. 2 suggest that ND corn has 5.3% more ME than YD corn. The additional energy provided by ND corn improves G:F in both nursery and grow-finish pigs, and ND corn offers a means of formulating diets more concentrated in energy than YD corn.

Animal Feed↗

PubMed2001

Phosphorus bioavailability, growth performance, and nutrient balance in pigs fed high available phosphorus corn and phytase.

Three experiments were conducted to evaluate P bioavailability, growth performance, and nutrient balance in pigs fed high available P (HAP) corn with or without phytase. The bioavailability of P in normal and HAP corn relative to monosodiumphosphate (MSP) for pigs was assessed in Exp. 1. In a randomized complete block design, 96 pigs (average initial BW 9.75 kg) were fed eight diets for 28 d. The reference and test diets were formulated by adding P as MSP, HAP, or normal corn at 0, 0.75, or 1.5 g/kg to a corn-starch-soybean meal basal diet (2.5 g/kg P) at the expense of cornstarch. Plasma inorganic P concentration responded linearly (P < 0.05) to supplemental P intake. Estimates of P bioavailability from HAP andnormal corn when plasma P was regressed on supplemental P intake were 46 and 33%, respectively. In Exp. 2 and 3, pigs were fed corn-soybean meal-based diets containing HAP corn or normal corn and 0 or 600 units of phytase per kilogram in a 2 x 2 factorial arrangement (two corn sources and two levels of phytase). In Exp. 2, 48 crossbred pigs (barrow:gilt, 1:1) averaging 9.25 kg were used to evaluate growth performance. There were no detectable interactions between corn source and phytase for any of the performance criteria measured. Pigs receiving normal corn had the lowest (P < 0.05) BW and rate of gain. Feed efficiency was lower (P < 0.05) in pigs fed normal compared with those fed the HAP corn phytase-supplemented diet. In Exp. 3, 24 crossbred barrows averaging 14.0 kg were used to evaluate nutrient digestibility. There were no detectable interactions between corn and phytase for any of the N and Ca balance criteria. Nitrogen and Ca retention were improved in pigs receiving HAP corn with phytase (P < 0.05). Retention and digestibility of P was lowest (P < 0.01) for pigs on normal corn diet without phytase. The percentage of P digested and retained was improved and fecal P excretion lowered (P < 0.05) by feeding HAP corn. The results of this study indicate that the bioavailability and balance of P in HAP corn is superior to that of normal corn. The addition of 600 phytase units (Natuphos 600, BASF) to HAP corn-based diets further improved P digestibility and reduced P excretion in pigs.

6-Phytase↗

PubMed1998

Effects of ground, steam-flaked, and steam-rolled corn grains on performance of lactating cows.

Five types of processed corn were compared to determine the effects of processing on lactational performance and nutrient digestibilities in dairy cows. Forty lactating Holstein cows averaging 160 +/- 60 d in milk were randomly divided into five groups on the basis of pretreatment milk yields and were fed diets containing 40% corn grain for 56 d. Treatments were 1) finely ground corn, 2) coarsely ground corn, 3) steam-flaked corn at a low density, 4) steam-flaked corn at a medium density, and 5) steam-rolled corn. Cows fed the diet containing steam-flaked corn at a medium density had a higher milk yield (37.1 kg/d) than did cows fed the diets containing coarsely ground corn, steam-flaked corn at a low density, or steam-rolled corn; cows fed the diet containing finely ground corn had an intermediate milk yield (35.5 kg/d). Efficiency of feed utilization was greater, and dry matter intake was lower, for cows fed the diet containing finely ground corn than for cows fed the other diets. The fat content of milk was higher for cows fed the diets containing coarsely ground corn and steam-rolled corn than for cows fed the diet containing steam-flaked corn at a medium density. Milk protein and SNF contents and yields of protein, lactose, and SNF did not differ among diets. Apparent starch digestibilities in the total digestive tract were lower for diets containing coarsely ground corn (87.4%) and steam-rolled corn (91.3%) than for the other diets (X = 96.3%). Milk yield was highest for cows fed the diet containing steam-flaked corn with a medium density. Fine grinding resulted in the greatest efficiency of feed utilization.

Animal Feed↗

PubMed2002

IgE-mediated allergy to corn: a 50 kDa protein, belonging to the Reduced Soluble Proteins, is a major allergen.

BACKGROUND: Although corn is often cited as an allergenic food, very few studies have been devoted to the identification of corn allergens and corn allergy has been rarely confirmed by double-blind, placebo-controlled food challenge (DBPCFC). Recently, Pastorello et al. (1) identified some salt-soluble IgE-binding proteins of corn flour as potential allergens. One of these, corresponding to corn Lipid Transfer Protein (LTP), appeared to be the major one. The aim of this study was to verify the clinical significance of the skin prick test (SPT) and CAP-FEIA CAP-System IgE fluozoenzyme immunosorbent assay (Pharmacia Diagnostic, Uppsala, Sweden) positivities to corn and to identify the presence of IgE-binding proteins in the corn flour salt-insoluble protein fractions (comprising up to 96% of the total protein) using sera of patients with DBPCFC-documented food allergy to corn. In addition the effect of cooking and proteolytic digestion on the corn allergens was investigated. METHODS: Sixteen subjects with SPT and CAP-FEIA positivities to corn flour were examined. Only six of them complained of suffering from urticaria and/or other symptoms after ingestion of corn-based foods. The patients were food challenged with cooked corn flour (polenta). IgE-binding proteins were detected by immunoblotting. The digestibility of the IgE-binding proteins was examined during a pepsin attack followed by a pancreatin digestion performed on a cooked corn flour sample. RESULTS: Oral challenge was positive only for six patients with symptoms after ingestion of corn. A 50 kDa protein, belonging to the corn Reduced Soluble Protein (RSP) fraction was recognized by the serum IgE of all the DBPCFC-positive subjects and resulted to be resistant to both heating and peptic/pancreatic digestion. SPT with the purified RSP fraction gave positive results for all of the DBPCFC-positive patients examined. CONCLUSIONS: SPT and CAP-FEIA positivities to corn flour had no clinical significance for most of the patients and food allergy to corn has to be proved by DBPCFC. A salt-unextractable protein of 50 kDa, belonging to the RSP fraction, represents a potential allergen in food hypersensitivity to corn because of its stability to cooking and digestion.

Allergens↗

PubMed2003

High available phosphorus corn and phytase in layer diets.

High available phosphorus corn (HAP) developed using the low phytic acid 1-1 (lpal-1) allele of the corn LPA1 gene containing 0.27% P, with 0.17% nonphytate P (NPP), was compared to near isogenic normal corn (LPA1), which contained 0.23% P and 0.05% NPP. Five levels of NPP from either HAPC or normal corn (0.40, 0.35, 0.30, 0.25 and 0.20% + 300 phytase units (FTU)/kg microbial phytase) were combined in a 2 x 5 factorial experiment for a total of 10 dietary treatments. Each dietary treatment was fed to eight replicate cages with five Hy-Line W-36 hens per replicate cage from 20 to 40 wk of age. Feed consumption and egg production were not significantly affected by dietary NPP level or corn type. Feed conversion ratio (g feed:g egg mass) was improved at the 0.35% NPP level (1.856) compared to the other levels of NPP--0.40, 0.30, 0.25, and 0.20% + phytase having feed conversion ratios of 1.872, 1.905, 1.930, and 1.898, respectively. Egg weight and egg mass decreased significantly as dietary NPP decreased; diets with 0.20% NPP plus phytase had equal egg mass to the 0.35 and 0.40% NPP diets. A significant corn type x NPP interaction effect was observed for egg weight, such that within the HAP corn diets, egg weight decreased more markedly at the 0.25% NPP levels compared to the normal corn 0.25% NPP diets. Specific gravity was not affected by dietary treatment, but percent dry shell was improved at the lower AP levels and with phytase treatment. Dietary NPP level and corn type had no significant effect on bone ash. Excreta levels of total phosphorus decreased significantly as dietary NPP decreased and were lower in the HAP corn excreta compared to normal corn excreta. Total P, Ca, Zn, Cu, and Mn retention were significantly affected by NPP level and corn type. HAP corn reduced Ca, Zn, Cu, and Mn retention compared to normal corn; this negative effect was alleviated by phytase supplementation to HAP corn diets. HAP corn allowed less dicalcium phosphate supplementation in layer diets compared to normal corn while supporting equal egg production. Phytase supplementation of low NPP diets had no significant positive effects on egg production parameters in either corn type diets.

6-Phytase↗

PubMed1987

Nutritive value of high oil corn for poultry.

Several experiments were conducted to evaluate the nutritional value of high oil corn for poultry relative to that of conventional (CONV) corn. The variety of high oil corn (HO1) evaluated in most trials contained 6.0% oil and 9.6% protein on a 10% moisture basis. The protein quality of HO1 and CONV corn was assessed with female crossbred chicks fed corn as the sole source of dietary protein. There was no difference in either protein efficiency ratio or in net protein ratio between the two types of corn. True metabolizable energy (TME) and nitrogen-corrected TME (TMEn) values of HO1 corn were determined using adult roosters. The TME and TMEn values of HO1 corn were approximately 4.5% higher than those of CONV corn. Two experiments were conducted to evaluate the use of high oil corn varieties, containing from 6 to 13% oil, in practical diets of commercial broiler chicks from 8 to 22 days posthatching. Weight gain, gain-to-feed ratio, and skin and plasma pigmentation were improved in chicks fed 24% protein diets containing high oil corns compared with those fed the same diet containing CONV corn; magnitude of response was highly correlated to oil content of the corn. The relative value of HO1 corn in practical laying hen diets was examined in a 15-wk experiment. Hens fed a 17% protein diet containing HO1 corn from 23 to 38 weeks of age had a better feed-to-egg ratio than those fed the same diet containing CONV corn when the corn sources were substituted on an isonitrogenous basis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1999

Effect of wheat and corn variety on fiber digestion in beef steers fed high-grain diets.

Six Salers steers, fitted with ruminal and duodenal cannulas, were used in a double 3x3 Latin square design to assess the depressive effect of the nature of wheat, flint corn, and dent corn on fiber digestion in animals fed high-concentrate diets, and to determine the mechanisms involved in these negative digestive effects. Diets were balanced to be equal in starch content (47.7+/-2.3%). The three cereals were characterized by ruminal starch digestibilities of 86.6, 60.8, and 34.8% for the wheat, dent corn, and flint corn, respectively. Ruminal digestion of NDF was lower with wheat- than with corn-based diets (49.4 vs. 55.2%; P<.001), and with dent corn than with flint corn (53 vs. 57.3%; P<.01). Degradability of hay in nylon bags was not affected by the grain source in the diet (P>.1). The mean retention time of forage particles in the rumen was similar between wheat and corn diets (P>.1), but it was lower for steers fed dent corn than for those fed flint corn (P<.05). Most fibrolytic activities of the solid-associated microorganisms were lower (P<.05) in animals fed wheat than in those fed corn. Differences in fibrolytic activities of the solid-associated microorganisms between the two corn genotypes were not statistically significant (P>.1), but activities of all fibrolytic enzymes were lower (P<.05) with the dent than with the flint corn diet. Protozoal number in ruminal fluid was lower in animals receiving wheat than in those fed corn (177 vs. 789x10(3)/mL; P<.001) and was related to the high ruminal acidity (P<.01) of the wheat diet. Large modifications in the rumen microbial ecosystem between the two corn genotypes were not visible in protozoal numbers or pH. Total-tract digestion of NDF was the same for wheat and for corn diets, averaging 55% for the three diets. A postruminal compensation of NDF digestion (14% of the total tract NDF digestion) seemed to occur with the wheat diet. The lack of any postruminal NDF digestion (0%) with the two corn diets may suggest negative digestive interactions in the hindgut similar to those in the rumen.

Animal Feed↗

PubMed1987

Energy value of corn wet milling by-product feeds for finishing ruminants.

Five trials were conducted to evaluate the energy value of corn wet milling by-products in finishing diets. In trials 1 (45 finishing lambs, 34 kg) and 2 (70 digestion wethers, 32 kg), Rambouillet X Suffolk lambs fed corn gained faster (P less than .10), more efficiently (P less than .10) and had higher (P less than .01) digestibilities of neutral and acid detergent fiber (NDF, ADF) and starch than lambs fed dry corn gluten feed (DCGF). Lambs fed wet corn gluten feed (WCGF) consumed less feed (trial 1, P less than .05; trial 2, P less than .01), were more efficient (P less than .01) NDF and ADF digestibilities than lambs fed DCGF. Starch, NDF and ADF digestion were higher (P less than .01) for lambs fed WCGF vs wet corn bran (WCB). Lambs fed WCGF gained faster (P less than .10) and consumed more (trial 1, P = .12; trial 2, P less than .10) feed than lambs fed WCB. Dried corn bran increased (trial 1, P less than .05; trial 2, P less than .01) intake and increased (P less than .01) dry matter digestion (DMD) compared with WCB. In trial 3, rates of in vitro dry matter and NDF disappearance were similar among by-product feeds. In trial 4 (50 individually fed Shorthorn-Hereford-Angus steers, 316 kg), steers fed WCGF tended to consume more (P = .14) feed than steers fed DCGF. Corn gluten feed (CGF) replacing 0 to 46% corn decreased gain (linear, P less than .05) and DMD (linear, P less than .10), while starch digestion was highest for 23% CGF (quadratic, P less than .01). A level X CGF type interaction (P = .15) occurred for efficiency due to the lower gain of steers fed 46% DCGF. The efficiency of CGF utilization was 97% that of corn when WCGF replaced 23 or 46% corn or DCGF replaced 23% corn. Dry CGF replacing 46% corn had 87% the value of corn. In trial 5 (186 Hereford-Angus cattle, 310 kg), DCGF replacing 25 and 50% corn had 97 to 100% the efficiency of corn, while intake and gain were not affected. Dry CGF replacing 25 and 50% corn silage increased (linear, P less than .05) intake 11.3% and gain 13.8%. In ruminants, CGF is highly digestible and feed efficiency is similar to corn when WCGF is fed up to 50% of the grain component or when DCGF is fed up to 25% of the grain component.

Animal Feed↗

PubMed2005

Proteolysis, fermentation efficiency, and in vitro ruminal digestion of peanut stover ensiled with raw or heated corn.

Peanut stover (PS) is similar to full-bloom alfalfa hay in chemical composition. The objective of this study was to assess the effect of adding raw or heated corn meal to PS at ensiling on silage N components, fermentation acids, and digestion by ruminal microorganisms. The PS was collected after harvesting of peanuts and ensiled immediately without and with addition of raw or heated corn meal (100 g/kg of fresh weight). Corn was added to PS so that the initial mixture would contain adequate dry matter (DM) (approximately 30%) and additional nonfiber carbohydrate to enhance silage fermentation. After 8 wk of silo fermentation, corn-treated silages contained less structural carbohydrates but more non-fiber carbohydrates compared with the untreated control. A shift from hemicellulose to nonfiber carbohydrate use during silage fermentation was evident by corn treatment. Additional corn at ensiling resulted in silage N with less water-soluble N, protein N, nonprotein N, nonprotein nonammonia N (peptides plus amino acids), and ammonia N. Based on changes in soluble nonprotein N before and after ensiling, the amount of proteolysis was approximately 66% for control silage and was nearly 40% lower in response to corn treatment. Adding corn increased silage lactic acid, but both acetic and propionic acids decreased. These changes were reflected in the lower pH and higher fermentation efficiency with corn-treated silages. More DM was digested and greater amounts of volatile fatty acids, except for branched-chain acids, were produced in vitro by ruminal microorganisms with corn-treated silages. In addition, incubations with silage treated with heated corn contained higher concentrations of acetic and propionic acids compared with raw corn. In vitro ammonia accumulation per unit of DM digested was lower for corn treatments than the control, and for heated corn vs. raw corn-treated silage. These results indicate that supplementation of either raw or heated corn on PS at ensiling could minimize proteolysis and improve fermentation efficiency. Advantages from using heated vs. raw corn could extend beyond silage fermentation and include rumen microbial fermentation.

Acetic Acid↗

PubMed1987

Characterization of in situ dry matter and nitrogen digestion of various corn grain forms.

Corn was harvested and stored as either dried shelled, dried ear, high moisture shelled, or high moisture ear. Shelled corns were rolled and ear corns were ground through a forage harvester. High moisture corns were stored in sealed drums. Each corn type was subjected to in situ ruminal digestion with incubation times through 100 h for both original forms and ground at 5 mm. Dry matter, N, and nonprotein DM digestion rates were determined. Unground dried shelled corn possessed the fastest and high moisture ear corn the slowest rate of DM digestion; however, extent of digestion was greatest for high moisture corns within 16 h of ruminal exposure. Grinding increased the rate of shelled corn digestion. Nitrogen digestion rate was fastest for high moisture ear corn and slowest for dried shelled corn. Grinding increased the rate of nitrogen digestion for all corn forms except high moisture shelled corn. Generally, correction for bacterial nitrogen contamination resulted in increased rate of nitrogen digestion. Dried shelled corn possessed the fastest rate of nonprotein DM digestion. Ratio of nitrogen to nonprotein DM rates ranged from .56 to 1.24 for dried shelled corn and high moisture ear corn, respectively. Grinding narrowed this range. Digestion rates of corn forms may not necessarily reflect initial (1 to 16 h) extent of ruminal nutrient availability.

Animal Feed↗

PubMed2003

Apparent ileal digestibility of amino acids and the digestible and metabolizable energy content of high-oil corn varieties and its effects on growth performance of pigs.

Two experiments were conducted to compare the nutritional value of normal and high-oil corn for pigs. The normal corn and the two varieties (high-oil corns A and B) of high-oil corn contained 4.41, 7.35 and 8.86% ether extract, on DM basis, respectively. In experiment 1, six non-littermate crossbred barrows (37.8 +/- 1.3 kg BW) were fitted with ileal T-cannulas and used in a double replicated Latin Square digestion trial. Three diets were formulated containing 96.6% of one of the three varieties of corn as the only protein source. Chromic oxide (0.4%) was added as a digestibility marker. Additional vitamins and minerals were added to meet requirements. The digestible energy concentrations for normal corn and high-oil corn A and B were 16.53, 16.99 and 17.07 MJ/kg while the metabolizable energy values were 15.82, 16.32 and 16.36 MJ/kg, on DM basis, respectively. The ileal amino acid digestibility of high-oil corn was generally higher than that of normal corn with significant differences being observed for the essential amino acids isoleucine and phenylalanine. In experiment 2, 96 pigs (8.01 +/- 0.14 kg BW) were used to evaluate four diets in a 2 x 2 factorial design conducted over a 35-day period. Corn variety (high-oil vs. normal corn) and nutrient density (high content of protein and ME vs. low content of protein and ME) were set as the two main effects. During the first 14 days, pigs fed high-oil corn diets consumed more feed and tended to get higher daily gain than pigs fed normal corn. Over the entire 35-day experiment, increasing dietary nutrient density increased daily gain and tended to increase feed conversion, while variety of corn had no significant effects on performance. Overall, the present results indicate that the energy concentration and ileal amino acid digestibility of high-oil corn varieties were equal or superior to those in normal corn and therefore they should be able to be effectively utilized in diets fed to swine.

Amino Acids↗

PubMed2002

Survey for fumonisin B1 in Korean corn-based food products.

Seventy-six corn-based foods collected in Seoul, Korea, including corn flakes, corn snack, cornstarch, corn for popping, roasted corn for tea, canned sweet corn and other corn products were analysed for the occurrence of fumonisin B(1) (FB(1)) by using direct competitive enzyme-linked immunosorbent assay (dcELISA) and high-performance liquid chromatography (HPLC). The average recoveries of FB(1) from the corn flakes sample in the range 5-1000 ng g(-1) were 104% by dcELISA and 82% by HPLC. The limits of detection were approximately 5 ng g(-1) by dcELISA and 20 ng g(-1) by HPLC. The incidences and mean levels of FB were 73.3, 78.6, 50, 58.3, 17.6 and 40% and 41.8, 67.9, 114, 256, 172 and 22 ng g(-1) from corn flakes, corn snack, corn starch, corn for popping, roasted corn for tea and other corn products, respectively, by dcELISA. No FB(1) was found in canned sweet corn. The results obtained by dcELISA were correlated to those by HPLC for FB(1) (r(2) = 0.992). This is the first report on the occurrence of FB(1) in corn-based foods in Korea.

Carboxylic Acids↗

PubMed2000

Crop processing and chop length of corn silage: effects on intake, digestion, and milk production by dairy cows.

Effects of corn silage crop processing and chop length on intake, digestion, and milk production were evaluated. Corn silage treatments were harvested at one-half milkline stage of maturity (65% whole-plant moisture content) and at 0.95-cm theoretical length of cut without processing (control) or 0.95-, 1.45-, or 1.90-cm theoretical length of cut with processing at a 1-mm roll clearance. Twenty-four multiparous Holstein cows averaging 71 d in milk at trial initiation were in a replicated 4 x 4 Latin square design with 28-d periods; one square was comprised of ruminally cannulated cows for rumen measurements. Corn silage treatments were fed in total mixed rations containing 50% forage (67% corn silage and 33% alfalfa silage) and 50% corn and soybean meal based concentrate (dry matter basis). Dry matter intake (25.9 vs. 25.3 kg/d) and milk (46.0 vs. 44.8 kg/ d) and fat (1.42 vs. 1.35 kg/d) yields were higher for the processed corn silage treatments compared with the control corn silage. Within the processed corn silage treatments, there were no chop length effects on intake, milk production, or milk composition. Chewing activity was not different among the four corn silage treatments averaging 12 h/d. Total tract digestion of dietary starch was lower for control corn silage (95.1%) compared with fine, medium, and coarse processed corn silage treatments, which averaged 99.3%. Total tract digestion of dietary NDF was reduced for fine-processed corn silage compared with control corn silage and coarse-processed corn silage (28.4% vs. 33.9 and 33.7%, respectively). Processing corn silage improved dry matter intake, starch digestion, and lactation performance. Under the conditions of this study and with theoretical lengths of cut ranging from 0.95 to 1.90 cm, length of chop effects were minimal in processed corn silage.

Animals↗

PubMed1998

Determination of the mycotoxin fumonisins in gluten-free diet (corn-based commodities) in the Czech Republic.

The fumonisins, mycotoxins produced by Fusarium moniliforme, are known to occur worldwide as natural contaminants of corn. They are associated with several animal diseases and are a potential threat to human health. A total of 127 samples of corn-based foods (gluten-free diet) in the Czech Republic were analysed by Ridascreen Fumonisin Fast ELISA methods in years 1995-1996. Eighty eight % of the corn-based foods were found to be positive for fumonisins (FB1, FB2, FB3) and 12% of the examined corn-based foods laid below of a determination limit which was about 9 ng fumonisins/g corn-based foods. The highest fumonisin contamination levels were recorded in extruded corn products containing up to 1,808 micrograms/kg of fumonisins. Levels ranging from < 9 to 1,243 ng/g fumonisins were detected in polenta. Lower levels of fumonisins were found in other commodities, such as corn flour (up to 487 ng/g), corn instant porridge (up to 788 ng/g), and corn pastes (511 ng/g). Intake of fumonisins from several corn-based foods (gluten-free diet) for the population with coeliac disease was estimated. The highest estimate of exposure dose of fumonisins was determined from corn-extruded bread: 3.2 micrograms/person/day (mean of measured values). Daily intake of fumonisins from polenta is expected 2.8 micrograms/person/day (mean). The lower exposure dose of fumonisins we can expect from corn instant porridge, corn postes and other corn products--corn and amaranth biscuit, corn beverage: 0.9, 1.1 and 0.3 micrograms/person/day (mean) respectively.

Celiac Disease↗