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PubMed2001

In situ studies on the structure of copper oxide/zinc oxide catalysts.

Cu/ZnO supported on alumina is a well-known catalyst for steam reforming of methanol. In this work it is attempted to assess the influence of elemental composition on the resulting active copper phase. XAFS measurements of calcined precursors were carried out at the Cu K edge and the Zn K edge. Corresponding RDF show that both copper oxide and zinc oxide exhibit considerable deviations from a linear dependence of their structure on the composition coinciding with changes in phase composition of hydroxycarbonate precursor. From time-resolved in situ experiments at the Cu K edge the degree of reduction can be monitored using a combination of factor analysis (PCA) and least-squares XANES fitting with suitable reference spectra (e.g. Cu metal, Cu2O, and CuO). It is shown that Cu2O forms prior to Cu. The extent of reduction to Cu exhibited a typical nucleation growth behavior with an enhanced reaction rate for more diluted samples. Adding oxygen to the feed gas leads to the formation of mixed Cu2+ and Cu+ phases accompanied by a complete loss of activity in methanol steam reforming. After switching back to steam reforming conditions the activity is regained.

Journal Article↗
PubMed2005

Effect of flame cleaning of ceramic surface on the bond strength of composite to ceramic.

This study tested the hypothesis that flame cleaning of ceramic surface would increase the bond strength of composite to ceramic than pressure-vaporized steam cleaning. Eris and IPS-Empress ceramic blocks were fabricated, polished (control), airborne-particle abraded with 50-microm alumina particle (A), etched with 5% hydrofluoric acid gel for 2 min (E), or treated with a combination of A and E (AE). They were subjected to either steam cleaning for 20 s or flame cleaning over a gas burner for 2 s. Followed by an application of an adhesive resin, a composite was built-up. Twenty micro-tensile test specimens (approximately 0.9 x 0.9 x 16 mm) were obtained from each group and loaded to failure under tensile force using a universal testing machine at a crosshead speed of 0.5 mm min(-1). anova showed statistically significant differences in the mean bond strength by ceramic, surface roughness, and cleaning method (P < 0.0001). The groupings of the mean bond strength were as follows: flame-cleaned > steam-cleaned; IPS-Empress > Eris; and AE > E > A for IPS-Empress and AE > E approximately A for Eris (Duncan's multiple analysis; alpha = 0.05). This in vitro study suggests that mechanical bond of composite to ceramic can be improved with flame cleaning of ceramic surface.

Aluminum Silicates↗
PubMed2007

Sterilization method of platelet storage containers affects in vitro parameters.

BACKGROUND AND AIM: Four butyryl trihexyl phthalate plasticized polyvinyl chloride (BTHC-PVC) containers were compared for storage of leukoreduced platelet concentrates (LR-PC): three ethylene oxide (EtO) sterilized (Gambro, Haemonetics, Fresenius), and one steam-sterilized (Fresenius). METHODS: LR-PCs were made from 5 buffy coats and 300 ml Composol additive solution, and leukoreduced by filtration. Four LR-PCs were pooled and subsequently divided over the 4 BTHC-PVC bags to prevent donor-dependent differences, and sampled for in vitro analysis on day 1, 2, 5, 7 and 9. RESULTS: The pH values on day 9 were (mean +/- SD, n = 10): 7.12 +/- 0.03 (Gambro), 7.12 +/- 0.04 (Haemonetics), and 7.07 +/- 0.09 (Fresenius, EtO-sterilized) (not significantly different), vs. 6.91 +/- 0.12 (Fresenius, steam-sterilized; P < 0.001 vs. all EtO-sterilized bags). LR-PCs stored in the steam-sterilized bag exhibited significantly higher glucose consumption and lactate production (P < 0.001 vs. all EtO-sterilized bags). CONCLUSION: All BTHC-PVC containers allow storage of LR-PCs for up to 9 days with good in vitro parameters. However, the method of sterilization affects the storage conditions of the LR-PCs in these bags.

Blood Platelets↗
PubMed1983

Implanted artificial heart with radioisotope power source.

An atomic artificial heart for orthotopic implantation was developed with the following characteristics: volume, 1.2 L; weight, 1.5 kg; radioisotope power, 45 W; operating life, up to 5 years; hemodynamics, similar to natural hemodynamics. The artificial heart includes a thermal drive with systems for regulating power, feeding steam into the cylinders, return of the condensate to the steam generator, and delivery of power to the ventricles and heat container. The artificial heart is placed in an artificial pericardium partially filled with physiologic solution. It uses a steam engine with two operating cylinders that separately drive the left and right ventricles. There is no electronic control system in the proposed design. The operation of the heat engine is controlled, with preservation of autoregulation by the vascular system of the body. The separate drives for the ventricles is of primary importance as it provides for operation of the artificial heart through control of cardiac activity by venous return. Experimental testing on a hydromechanical bench demonstrated effective autoregulation.

Electric Power Supplies↗
PubMed1967

Energy needs versus environmental pollution: a reconciliation?

In this article I have presented, for discussion, a proposed system for energy generation by which the principal sources of environmental pollution by power plants could be eliminated. For stationary power plants the concept appears feasible technically and, according to my " horseback estimates," perhaps economically as well, depending upon the economic value of the by-products of sulfur, CO(2), water, and possibly nitrogen, and upon the price we are willing to pay for a clean environment .Thus, a more thorough engineering and economic analysis to explore these and other factors in greater depth seems warranted. In the case of turbine-driven vehicles, the technical and economic feasibility of widespread distribution and handling of the fuel constitutes a serious question, but one which deserves equally serious consideration before the possibility is discounted. The reports of the cited study panels notwithstanding, the technology required for the proposed system exists today, with one exception. This exception (which is not essential for trial of the system but will be required for its complete fruition) is the development of a nuclear reactor for the prime purpose of delivering process heat for the steam reforming of natural gas and, ultimately, for gas production from coal in a continuous process, such as those discussed by Pieroni et al. (16). Today's intermittent processes of coking and gas production are both archaic and themselves large sources of atmospheric pollution, and a development program aimed at advancing the technology of the coal industry in this regard would seem long overdue. The report of the PSAC Environmental Pollution Panel recommended "demonstration of the feasibility and economy of new developments for abating or controlling pollution through their use at Federal installations" and suggested the coalburning TVA power plants as a likely place for such demonstration. This suggestion is doubly appropriate since the TVA is in a region of subnormal " atmospheric ventilation" (8). By design these plants are adjacent to the AEC's Oak Ridge National Laboratory, and such a location would seem ideal for an experiment on the wedding of nuclear and fossil sources of energy. In comments on a preliminary draft of this article, proponents of "conventional " nuclear power pointed out that such power is hard to beat on the basis of cost, and that dissipation of heat to the air by way of cooling towers can also be accomplished in conventional plants (17). These observations are individually correct but not compatible: the low power costs cited are for very large plants [of the order of 1000 mega-watts lectrical) and larger], and the costs of cooling towers and associated equipment needed to dissipate such large amounts of heat [of the order of 2000 megawatts (thermal)] to air from a closed cycle would offset the power cost advantage of the large plant. In regard to the proposed use of nuclear process heat, Weinberg (20) has expressed doubt that much advantage can be derived from this approach because the temperatures involved are too high for low-cost reactors, and heat transfer from surfaces could involve materials problems. In the case of gas production, this is indeed an anticipated problem-not a technologically insuperable one, but a problem of reducing the cost of the materials required (16). Indeed, Weinberg himself has mentioned this possible use of nuclear heat in a recent publication discussing the steam reforming of coal to liquid fuel(21). Also, an improved process for synthesizing methane from lignitec has recently been reported (22). Since the earlier studies date back a decade, a new look at the problems and costs involved relative to the benefits to be derived (not the least of which could be new vigor for the coal industry) would seem to be in order. In the case of steam reforming of natural gas, the temperature level (about 1500 degrees F) is such that the technology is available today, and a process-heat-reactor design study could be initiated without awaiting further developments.

Air Pollution↗
PubMed1990

Production of the antibiotic phenazine-1-carboxylic Acid by fluorescent pseudomonas species in the rhizosphere of wheat.

Pseudomonas fluorescens 2-79 and P. aureofaciens 30-84 produce the antibiotic phenazine-1-carboxylic acid and suppress take-all, an important root disease of wheat caused by Gaeumannomyces graminis var. tritici. To determine whether the antibiotic is produced in situ, wheat seeds were treated with strain 2-79 or 30-84 or with phenazine-nonproducing mutants or were left untreated and then were sown in natural or steamed soil in the field or growth chamber. The antibiotic was isolated only from roots of wheat colonized by strain 2-79 or 30-84 in both growth chamber and field studies. No antibiotic was recovered from the roots of seedlings grown from seeds treated with phenazine-nonproducing mutants or left untreated. In natural soils, comparable amounts of antibiotic (27 to 43 ng/g of root with adhering soil) were recovered from roots colonized by strain 2-79 whether or not the pathogen was present. Roots of plants grown in steamed soil yielded larger bacterial populations and more antibiotic than roots from natural soils. In steamed and natural soils, roots from which the antibiotic was recovered had significantly less disease than roots with no antibiotic, indicating that suppression of take-all is related directly to the presence of the antibiotic in the rhizosphere.

Journal Article↗
PubMed2000

Optimization of immunohistochemical methods using two different antigen retrieval methods on formalin-fixed paraffin-embedded tissues: experience with 63 markers.

Formalin fixation produces cross-links between the proteins and the fixative that alter the ability of some antibodies to recognize antigens. We used formalin-fixed, paraffin-embedded tissues to compare two different antigen retrieval methods for 63 antibodies used in the diagnosis of infectious and neoplastic diseases of animal species. Eighty-four percent of the antibodies needed some type of antigen retrieval for optimal results. Of those antibodies, 67.7% were monoclonal and 32.3% were polyclonal. Steam heat was the method of choice for 31 antibodies. Ten antibodies reacted only with steam heat, but 9 antibodies did not react when steam heat was used. Optimal results were obtained with enzyme digestion for 22 antibodies. Only 10 antibodies yielded optimal results without antigen retrieval; 64% of these antibodies were polyclonal. All antibodies against cytokeratins were optimally retrieved with proteinese K. Antigen retrieval appears to be necessary for the majority of antibodies when used with formalin-fixed, paraffin-embedded tissues.

Animal Diseases↗
PubMed1996

[Studies on Rehmanniae radix. III. The relation between changes of constituents and improvable effects on hemorheology with the processing of roots of Rehmannia glutinosa].

The relation between constituents and effects on hemorheology with processing of root of Rehmannia glutinosa was investigated. With the processing to dried or steamed root from crude root, the content of stachyose, which was the highest component in crude root, was decreased and the content of manninotriose was increased. Iridoid glycoside, catalpol, was gradually decreased with the processing. From these results, the content of carbohydrates and catalpol made it possible to estimate the quality of Rehmanniae Radix by processings. On the other hand, the change of pharmacological activities with the processing was investigated. The 50% ethanolic extract (BJ-ext) from steamed root of R. glutinosa increased erythrocyte deformability and erythrocyte ATP contents, inhibited polybrene-induced erythrocyte aggregation, and promoted an activity of fibrinolytic system. The extracts from crude or dried root had weak or no effect. The crude or dried root and steamed root of R. glutinosa showed the different pharmacological activities, and the quality of Rehamanniae Radix by processings may be estimated by investigation of correlation between the changes of constituents and improvable effects of hemorheology.

Adenosine Triphosphate↗
PubMed2000

Enzyme production of Trichoderma reesei Rut C-30 on various lignocellulosic substrates.

Economical production of cellulase enzyme is key for feasible bio-ethanol production from lignocellulosics using an enzyme-based process. On-site cellulase production can be more feasible with the process of separate hydrolysis and fermentation (SHF) than with simultaneous saccharification and fermentation, since the cost of enzyme is more important and a variety of substrates are available for the SHF process. Cellulase production using various biomass substrates available for SHF, including paper sludge, pretreated wood (steam exploded), and their hydrolysis residues, was investigated in shake flasks and a fermenter for their productivities and titers. Among the newspaper sludge, office paper sludge, and steam-exploded woods treated in various ways, the steam-exploded wood showed the best properties for substrate in cellulase production. The best titer of 4.29 IU/mL was obtained using exploded wood of 2% (w/v) slurry in the shake flask, and the titer with the same substrate was duplicated to about 4.30 IU/mL in a 3.7-L fermenter. Also, the yield of enzyme reached 215 IU/g of substrate or 363 IU/g of cellulose. Despite various pretreatment attempts, newspaper and office paper substrate was inferior to the exploded-wood substrate for cellulase production. However, hydrolysis residues of papers showed quite promising results. The hydrolysis residue of office paper produced 2.48 IU/mL of cellulase in 7 d. Hence, the utilization of hydrolysis residues for cellulase production will be further investigated in the future.

Biomass↗
PubMed1978

Inhibition of corrosion during autoclave sterilization of carbon steel dental instruments.

Comparisons were made of several dip-applied corrosion inhibitors for protection of carbon steel dental instruments during autoclaving. Although none were totally effective, several provided significant corrosion inhibition. Sodium nitrite and one proprietary inhibitor were about equally effective and notably superior to the other inhibitors investigated. Because sodium nitrite is a food preservative that is relatively harmless when ingested in small quantities, whereas commercial inhibitors are of proprietary composition and unspecified toxicity, we prefer to use sodium nitrite for corrosion inhibition during autoclaving. Sodium nitritie is readily available from chemical suppliers and is generally much less expensive than most commercial inhibitors. Although the autoclave used in this investigation is typical of many used in clinical situations, minor variations in design, steam impurities, and other unknown factors might effect the results. Further research is needed to determine the corrosive effects of impurities in the steam supply, residual detergents, method of postautoclave drying, steam supply deoxygenation, pH, and possibly the use of oxygen scavengers within the autoclave.

Alloys↗
PubMed2002

Chemical stimuli from corn plants affect host selection and oviposition behavior of Sesamia nonagrioides (Lepidoptera: Noctuidae).

The role of chemical stimuli in host selection and oviposition of Sesamia nonagrioides (Lef) was studied in the laboratory using eight corn hybrids. Female oviposition preference was evaluated on plants of the eight hybrids, their extracts in pentane and methanol, and volatiles collected by steam distillation in ether. Results from two-choice bioassays indicate various degrees of female preference to the hybrids. Four hybrids received more eggs than control plants, whereas the remainder received fewer eggs. Relatively similar results were obtained when filter paper sticks baited with pentane and steam distillation extracts were evaluated. Methanol extracts from all eight hybrids received fewer eggs than the methanol controls. Results showed that pentane and steam distillation extracts contain chemicals that elicit female oviposition response, while methanol extracts may contain chemicals that deter or repel females to oviposition.

Animals↗
PubMed1982

Effects of sterilization on periodontal instruments.

The sharpness of surgical instruments is of particular importance to the periodontist. In order to study the effects of sterilization on the cutting edges of periodontal curets and scalers, new sharpened instruments were sterilized 10 cycles with saturated steam, formalin-alcohol vapor or dry heat. The instruments were evaluated before and after sterilization with a scanning electron microscope. No visual damage to the cutting edges of stainless steel instruments was evident after sterilization by saturated steam at 250 degrees F, formalin-alcohol vapor at 270 degrees F or dry heat up to 340 degrees F. Carbon steel instruments were not damaged by formalin-alcohol vapor at 270 degrees F or dry heat up to 340 degrees F. Saturated steam caused oxidation and dulling of carbon steel instruments.

Carbon↗
PubMed2005

Determination of Cu, Pb, Fe, and Zn in plant component polymers of a hyperaccumulating plant.

Phytoremediation is an innovative technology that utilizes the natural properties of plants to remediate hazardous waste sites. For more cost-effective phytoremediation, it is important to utilize a hyperaccumulating plant after phytoremediation, i.e. the recovery of valuable metals and the production of useful materials. In this work, the determination of metals in plant component polymers in a fern, Athyrium yokoscense, as a hyper-accumulating plant was established using steam explosion, Wayman's extraction method, and ICP emission spectrometry. After A. yokoscense plants were treated by steam explosion, the steam-exploded A. yokoscense were separated into four plant component polymers, ie. water-soluble material fraction, holocellulose fraction, methanol-soluble lignin fraction, and residual lignin fraction. The concentrations of Cu, Pb, Fe, and Zn in these plant component polymers and the dry weights of plant component polymers were measured. These analytical process determining metals in the plants will contribute to not only the evaluation and the efforts of phytoremediation using a hyperaccumulating plant, but also to the development of more effective phytoremediation.

Biopolymers↗
PubMed2006

Maximising biogas in anaerobic digestion by using engine waste heat for thermal hydrolysis pre-treatment of sludge.

Dublin's Ringsend WWTP was designed to serve a population of approximately 1.2 million p.e. with a sludge production of 37,000 dry tonnes per year after upgrading to full secondary treatment. Several technical solutions were put forward as part of a design, build, finance and operate (DBFO) competition, with the chosen solution being a proposal by Black and Veatch for a combination of sequencing batch reactor (SBR) technology and anaerobic digestion with Cambi thermal hydrolysis pre-treatment (THP). The THP plant was built by Cambi and handed over to B&V in 2002. The plant is now operated by Celtic Anglian Water. In September 2004 a test was carried out on the mass and energy balance of the plant following 2 years of operation and is detailed in this paper. The process enables digestion at very high dry solids feed and low hydraulic retention time. The plant was built with three digesters of 4250 m3 each and is fed with hydrolysed sludge at 11% DS. There are four no. 1 MW Jenbacher engines operating mainly on biogas. Each pair of engines is fitted with a waste heat boiler with a capacity of one tonne steam per hour. These boilers have sufficient capacity to provide 80% of the steam required for the THP, which in turn provides all the heat for the subsequent digestion in the form of hydrolysed feed. There are two main biogas boilers for top up steam and other uses of the biogas including thermal oxidation of concentrated odours.

Anaerobiosis↗
PubMed2000

Splanchnic nitrogen metabolism by growing beef steers fed diets containing sorghum grain flaked at different densities.

The objective of this study was to determine effects of processing method, dry-rolled (DR) vs steam-flaked (SF), and degree of processing (flake density, FD) of SF sorghum grain on splanchnic (gut and liver) N metabolism by growing steers. Diets contained 77% sorghum grain either DR or SF at densities of 437, 360, and 283 g/L (SF34, SF28, and SF22, respectively). Eight crossbred steers (340 kg initial BW), implanted with indwelling catheters into portal, hepatic, and mesenteric veins and the mesenteric artery, were used in a randomized complete block design. Blood flows and net output or uptake of ammonia N, urea N (UN), and alpha-amino N (AAN) were measured across portal-drained viscera, hepatic, and splanchnic tissues. Plasma arterial, portal, and hepatic concentrations of individual amino acids were also measured. Decreasing FD linearly increased (P = .04) net absorption of AAN (51, 73, and 78 g/d for SF34, SF28, and SF22, respectively) and transfer (cycling) of blood UN to the gut (49, 48 and 64 g/d; P = .02). Net UN cycling averaged 38% of N intake across all diets. Hepatic uptake of AAN or UN synthesis, and splanchnic output of AAN and UN, were not altered by FD. Lowering FD linearly increased (P < or = .02) portal-arterial concentration differences for blood AAN and UN and plasma arterial concentrations for alanine. Steers fed SF compared to DR tended to have greater (P = .11) blood UN cycling (percentage of hepatic synthesis; 64 vs 50%) and decreased (P = .03) net splanchnic UN output (30 vs 50 g/d), but other net fluxes of N were not altered across splanchnic tissues. Steam-flaking compared to dry-rolling tended to decrease (P = .12) portal, but not hepatic, blood flow and increased (P < .01) hepatic-arterial concentration differences for blood UN. Except for a decrease (P = .01) in hepatic-arterial concentration differences of glutamine, plasma amino acid concentrations were not altered by feeding SF vs DR sorghum. Processing method (steam-flaking vs dry-rolling) or increasing the degree of processing (by decreasing FD) of SF sorghum grain resulted in greater transfer of blood UN to the gut. Reducing FD also linearly increased the absorption of AAN by growing steers, which explains (in part) published responses of superior performance by steers fed SF grains.

Animals↗
PubMed2001

Effects of grain sorghum planting density and processing method on nutrient digestibility and retention by ruminants.

Grain sorghum grown in 38-cm rows (high density [HD]) or 76-cm rows (normal density [ND]) was treated as follows: steam-flaked (SF), high-moisture-harvested followed by rolling and ensiling (HM), or dry-rolled (DR). Resulting grains were evaluated using lambs in two 5 x 5 Latin square digestion trials. Treatment diets contained either SF-HD, SF-ND, HM-HD, HM-ND, or DR-ND grain sorghum in two trials; a 90 or a 60% concentrate diet was fed in each trial. High-density planting increased (P < 0.10) the apparent absorption of P relative to ND planting for both 60 and 90% concentrate diets. Steam flaking decreased (P < 0.10) the apparent absorption of P in the 90% concentrate diet and decreased (P < 0.10) the apparent absorption of N in both the 90 and 60% concentrate diets. Despite differences in N digestibility, steam flaking and HM ensiling resulted in similar (P > 0.10) N retention as a percentage of N intake in both trials. However, changes in the distribution of N between feces and urine among processing methods could affect N content of manure and alter nutrient management strategies. These results indicate that both planting density and grain processing can alter the apparent absorption of grain sorghum P by ruminants. Furthermore, it seems that grain processing can alter the route of N excretion in ruminants without changing total N retention.

Agriculture↗
PubMed2006

Impact of corn vitreousness and processing on site and extent of digestion by feedlot cattle.

Eight cannulated Holstein steers (average BW: 251 kg) were used in 2 simultaneous 4 x 4 Latin squares in a split-plot arrangement to test the effects of processing method [dry-rolled (DR) vs. steam-flaked (SF); main plot] and vitreousness (V, %; subplot) of yellow dent corn (V55, V61, V63, and V65) on site of digestion of diets containing 73.2% corn grain. No vitreousness x processing method interactions were detected for ruminal digestion, but ruminal starch digestion was 14.4% lower (P < 0.01) for DR than for SF corn. Interactions were detected between vitreousness and processing method for postruminal (P < 0.10) and total tract digestion (P < 0.05). With DR, vitreousness tended to decrease (linear effect, P < 0.10) postruminal OM and starch digestion. With SF, vitreousness did not affect (P > or = 0.15) postruminal digestion of OM and starch. Postruminal N digestion tended to decrease (linear effect, P = 0.12) as vitreousness increased. Postruminal digestion was greater for SF than for DR corn OM (25.7%, P < 0.05), starch (94.3%, P < 0.10), and N (10.7%, P < 0.01). Steam flaking increased total tract digestion of OM (11%, P < 0.05), starch (16%, P < 0.01), and N (8.4%, P < 0.05) but decreased total tract ADF digestion (26.7%, P < 0.01). With DR, total tract starch digestion was lower for V65 (cubic effect, P < 0.10) than for the other hybrids. With SF, total tract starch digestion was not affected (P > or = 0.15) by vitreousness. Fecal starch and total tract starch digestion were inversely related (starch digestion, % = 101 - 0.65 x fecal starch, %; r2 = 0.94, P < 0.01). Ruminal pH was greater for steers fed DR than for steers fed SF corn (6.03 vs. 5.62, P < 0.05). Steam flaking decreased (P < 0.01) the ruminal molar proportion of acetate (24%), acetate:propionate molar ratio (55%), estimated methane production (37.5%), and butyrate (11.3%, P < 0.05). There was a vitreousness x processing interaction (P < 0.01) for acetate:propionate. For DR, acetate:propionate tended to increase (linear effect; P < 0.10) with increasing vitreousness. With SF, acetate:propionate was greater (cubic effect, P < 0.01) for V65. Starch from more vitreous corn grain was less digested when corn grain was DR, but this adverse effect of vitreousness on digestion was negated when the corn grain was SF. Of the 19% advantage in energetic efficiency associated with flaked over rolled corn grain, about 3/4 can be attributed to increased OM digestibility, with the remaining 1/4 ascribed to reduced methane loss.

Animal Feed↗
PubMed1986

Grain processing effects on starch utilization by ruminants.

Starch utilization may be markedly enhanced by proper grain processing; however, extent of improvement is primarily dependent upon the ruminant species, grain source and method of processing. Grain processing has less impact on starch digestion by sheep than cattle. The magnitude of improvement is inverse to the starch digestion values for nonprocessed (or minimally processed) grains. Utilization of sorghum grain starch is improved most by extensive processing, and then corn, with little improvement in barley starch digestion. Studies comparing processing effects on barley or wheat starch utilization by cattle were not found. Steam-flaking consistently improves digestibility of starch by cattle fed corn- or sorghum grain-based diets over whole, ground or dry-rolled processes. Other extensive processing methods appear to enhance starch digestibility of corn and sorghum grain to a similar extent as steam-flaking, but comparative data are too limited to quantitate adequately effects of these methods. This improvement in starch utilization appears to be the primary reason for enhanced feed conversion of cattle fed diets high in these processed grains. The major site of cereal grain starch digestion is usually the rumen. Processing increases microbial degradation of starch in the rumen and decreases amounts of starch digested post-ruminally. Rates of in vitro amylolytic attack of starch in cereal grains by both ruminal microbial and pancreatic enzyme sources are improved by processing methods employing proper combinations of moisture, heat and pressure. In vitro and in situ studies suggest that much of the increase in ruminal starch fermentation with steam-flaking is due to changes in starch granular structure, which produces additive effects beyond those of decreasing particle size. Thus, efficiency of ruminal starch fermentation by cattle appears to be improved by proper processing of corn and sorghum grain. Processing and grain source studies both suggest that maximal total tract starch digestibility is positively related to the extent of digestion in the rumen.

Animal Feed↗