Effect of electron-beam irradiation on the safety and quality of Fusarium-infected malting barley

Utilization of Fusarium-infected barley for malting may lead to mycotoxin production during malting and decreased malt quality. Electron-beam irradiation may prevent safety and quality defects and allow use of otherwise good quality barley. We evaluated electron-beam irradiation for preventing Fusarium growth and mycotoxin production while maintaining barley-malt quality characteristics. Four barley lots with varying deoxynivalenol (DON) concentrations were irradiated at 0, 2, 4, 6, 8, and 10 kGy. Treated barley was malted in a pilot-scale malting unit. Barley and malt were analyzed for Fusarium infection (FI), germinative energy (GE), aerobic plate counts (APC), mold and yeast counts (MYC), and DON. Malt quality parameters included malt extract, soluble protein, wort color, wort viscosity, free amino nitrogen, alpha-amylase, and diastatic power. FI, APC, and MYC decreased in barley with an increase in dosage. The APC and MYC for malts from barley exposed to 8-10 kGy were slightly higher than in other malted samples indicating that irradiation-resistant microflora could flourish during malting. Barley GE significantly decreased (3-15%) at 8-10 kGy. Although irradiation had no effect on DON in raw barley, DON decreased significantly (60-100%) in finished malts prepared from treated barley (6-10 kGy). Malt quality parameters were slightly affected by electron-beam radiation. The results suggest 6-8 kGy may be effective for reducing FI in barley and DON in malt with minimal effects on malt quality.

Evaluation of gaseous ozone and hydrogen peroxide treatments for reducing Fusarium survival in malting barley

The use of Fusarium-infected barley for malting can lead to mycotoxin production and decreased malt quality. Methods for treatment of Fusarium-infected barley might prevent these safety and quality defects and allow use of otherwise good-quality barley. Gaseous ozone and hydrogen peroxide (HP) were evaluated for effectiveness in reducing Fusarium survival while maintaining germinative energy (GE) in barley. Gaseous ozone treatments (GOT) included concentrations of 11 and 26 mg/g for 0, 15, 30, and 60 min. HP treatments included 0, 5, 10, and 15% concentrations with exposure times of 0, 5, 10, 15, 20, and 30 min. For GOT, in naturally Fusarium-infected barley, a statistically significant (P < 0.05) decrease (24 to 36%) of Fusarium survival occurred within 15 min of exposure at either concentration. GE was significantly (P < 0.05) affected by 30 min at both concentrations in naturally Fusarium-infected barley, but not in sound barley. GOT did not cause any significant (P > 0.05) effect on GE in sound barley at either concentration over the full 30-min exposure time. For HP, Fusarium survival was significantly decreased (50 to 98%) within 5 min of exposure. With the exception of two treatments (10 and 15% HP agitated for 20 min), GE was not statistically significantly different from the control in naturally Fusarium-infected barley. In sound barley, HP had no significant (P > 0.05) effect on GE. The results suggest that GOT and HP might have potential for treatment of Fusarium-infected malting barley.

Evaluation of hot water and electron beam irradiation for reducing Fusarium infection in malting barley

The use of Fusarium-infected barley for malting may lead to mycotoxin production and decreased product quality. Physical methods for the treatment of Fusarium-infected barley may prevent these safety and quality defects and allow the use of otherwise good quality barley. Hot water and electron beam irradiation were evaluated for their effectiveness in reducing Fusarium infection while maintaining germinative energy in barley samples. Hot-water treatments involved temperatures of 45, 50. 55, and 60 degrees C and treatment times of 0, 1, 5, 10, and 15 min. Electron beam irradiation involved doses ranging from 0 to 11.4 kGy. Treatment with water at 45 degrees C for 15 min resulted in a reduction in Fusarium infection from 32 to 1% after 15 min, with only a very slight reduction in germination. Treatment with water at 50 degrees C for 1 min resulted in a reduction in Fusarium infection from 32 to 2%, and no effect on germination was observed for up to 5 min of treatment. At higher water temperatures. Fusarium infection was essentially eliminated, but germination was also severely reduced. Electron beam irradiation of Fusarium-infected barley reduced Fusarium infection at doses of >4 kGy, and a slight increase in germination for dry samples was observed with doses of 6 to 8 kGy. Doses of >10 kGy significantly decreased germination. Physical methods may have potential for the treatment of Fusarium-infected malting barley.

Effects of preservation method and beta-glucanase supplementation on ileal amino acid digestibility and feeding value of barley for poultry

1. Effects of preservation method (drying or air-tight storage of whole grain and ensiling of rolled high-moisture grain) and beta-glucanase supplementation (Econase) on apparent ileal amino acid digestibilities and metabolisable energy content of barley were evaluated with Ross broiler chickens. In addition, the effect of barley preservation method was assessed using Leghorn cockerels. 2. Birds were given either a semi-purified soyabean meal basal diet or a mixture of the basal diet and barley (50:50 on dry matter basis). Apparent ileal digestibilities (AID) of nutrients were assessed using the slaughter technique. AID of nutrients and nutrient digestibility measured using excreta (AED) were determined using chromium mordanted straw as an indigestible marker. 3. In broilers, AID of amino acids, dry matter and organic matter were lower for dried than air-tight stored barley, particularly for diets based on ensiled barley. In cockerels, barley preservation method had no effect on amino acid AID. The AED of nutrients and nitrogen corrected apparent metabolisable energy content (AMEn) was highest for ensiled barley across both experiments. 4. beta-glucanase supplementation increased nutrient digestibility, phosphorus retention and AMEn content of air-tight stored and dried barley diets in particular but had only negligible effects on ensiled barley. Beta-glucanase improved the AID of amino acids in dried barley but not in air-tight stored or ensiled barley. 5. Amino acid digestibilities were lower in broilers than cockerels and the effect of barley preservation on feeding value of barley was different for broilers and cockerels.

The effects of amount of whole barley, barley bulk density, and form of roughage on feedlot lamb performance, carcass characteristics, and digesta kinetics

We conducted two feedlot trials and one metabolism trial to evaluate the effect of barley level, barley bulk density, and physical form of roughage on lamb growth performance and digesta kinetics. Level of whole barley (50, 70, 90%) and type of roughage (chopped or pelleted alfalfa) were evaluated in Trial 1 (50 d period). Trial 2 (50 d) evaluated barley bulk density (heavy = 671 and light = 607 kg/m3), form of roughage (pelleted or chopped alfalfa), and level of barley (80 or 40%). The influence of treatments used in Trial 2 on digesta kinetics was evaluated in Trial 3. Gain:feed increased and DMI decreased (P < .10) linearly with increasing level of barley, and ADG and DMI were greater (P < . 10) for lambs fed pelleted vs chopped alfalfa in Trial 1. The 70% barley diet produced the highest yield grade and kidney-pelvic fat and the lowest leg score among barley levels (P < .10). Lambs fed pelleted alfalfa had heavier carcasses and a thicker body wall than lambs fed chopped alfalfa (P < .02). In Trial 2, DMI was less and gain:feed greater (P < .01) for lambs fed the heavy barley than for lambs fed the light barley and for the 80% barley diet compared to the 40% barley diet. Lambs fed pelleted alfalfa had greater dressing percentages than lambs fed chopped alfalfa. Backfat and body wall thickness were greater (P < .10) for lambs fed the 80% barley diet than for those fed the 40% barley diet. In Trial 3, retention time of barley was greater (P < .10) for lambs fed light rather than heavy barley, and retention time of alfalfa was greater (P < .10) for lambs fed chopped compared with pelleted alfalfa. Acetate:propionate ratio was greater (P < .10) for lambs fed light vs heavy barley and lambs fed the 40 vs 80% barley diets. Ruminal pH was lower (P = .05) and in situ barley digestion greater (P = .03) over time in lambs fed the 80% barley diet than in lambs fed the 40% barley diet. Feedlot lamb ADG was not always greatest with high levels of barley; however, gain:feed improved at the higher barley levels. The higher barley levels seemed to result in fatter lambs.

Escape protein supplementation of steers fed grass silage-based diets

Beef steers (Trials 1 and 2, 280 +/- 2 kg; Trial 3, 330 +/- 2 kg) were fed diets of 67.5% wheat (Trial 1) or oat silage (Trials 2 and 3), 20.5% barley, and 12% supplement in randomized complete block design growth trials. Dietary treatments were graded levels of supplemental escape protein (EP) from corn gluten meal (Trial 1, 0 to 213 g/d escape protein) or animal by-products (1:1:1 DM mixture of blood, feather, and meat and bone meals, 0 to 223 or 0 to 317 g/d of escape protein in Trials 2 and 3, respectively) to titrate amounts needed to maximize steer live weight gain. As supplemental EP from corn gluten meal increased, steer live weight gain increased linearly (P < .001) and feed-to-gain decreased linearly (P < .001). Supplementation with 135 g/d of corn gluten meal EP (335 g/d of corn gluten meal) increased average daily gain from .76 to .91 kg/d. As supplemental EP from animal by-products increased, steer live weight gain increased quadratically (P < .05) and feed-to-gain decreased linearly (P < .01). Supplementation with 223 or 317 g/d of animal by-product EP increased live weight gain by .27 kg/d. Supplemental escape protein was needed to increase live weight gain of steers consuming ensiled forage diets due to low EP contents of silages (7, 3, and 23% of CP in Trials 1, 2, and 3, respectively) and barley (15, 27, and 22% of CP in Trials 1, 2, and 3, respectively) and limited microbial protein synthesis.

The relationship among dietary undetermined anion, acid-base balance, and nutrient metabolism in swine

Dietary undetermined anion (dUA) reflects, in part, the net acid load contributed by the diet. Although dUA is known to influence performance and nutrient metabolism of swine, a lack of knowledge impairs its application to diet formulation. This study was undertaken to separate the effects of dUA from the individual electrolytes that constitute its calculation. Eighteen 35-kg pigs were fitted with indwelling venous catheters and fed one of three barley and soybean meal-based diets: a control diet (C), an acidogenic diet containing calcium chloride (A), or a compensated acidogenic diet containing alkaline salts of sodium and potassium, as well as calcium chloride (CA). Compared with diet C, diet A lowered (P < .05) blood pH, bicarbonate, and base excess and increased (P < .05) urinary ammonium, titratable acid (TA), and net acid excretion (NAE). Diet CA returned blood acid-base values to normal and reduced urinary ammonium, TA, and NAE relative to diet A. Total nitrogen balance was unaffected by diet. Diet CA increased (P < .05) water intake and urine output. Diet A, but not CA, increased (P < .05) serum ionized Ca and C1. Apparent Ca and S digestibility and retention were reduced by diet A, but not by CA. Sodium retention was enhanced (P < .05) by diets A and CA; potassium retention was impaired (P < .05) by CA. Dietary UA altered systemic and renal acid-base balance in pigs. Mineral, but not nitrogen, metabolism was affected by both dUA and specific ion effects.

Effect of feeding blends of Fusarium mycotoxin-contaminated grains containing deoxynivalenol and fusaric acid on growth and feed consumption of immature swine

Experiments were conducted to determine the effect of feeding diets containing combinations of the Fusarium metabolites deoxynivalenol (DON) and fusaric acid (FA) to starter swine. In all experiments, pigs of approximately 8.2 kg initial weight were fed diets containing blends of mycotoxin-contaminated corn, wheat, and barley for 21 d with growth and feed consumption determined weekly. In the first experiment, diets were determined to contain 0 microgram DON/g + 58.9 micrograms FA/g (control), 4.4 micrograms DON/g + 57.1 micrograms FA/g, 6.0 micrograms DON/g + 48.6 micrograms FA/g, and 7.5 micrograms DON/g + 57.4 micrograms FA/g. The feeding of all diets containing DON caused significant linear depressions in growth and feed intake after only 1 wk. Lower concentrations of DON and FA were fed in the second experiment with diets containing 0 microgram DON/g + 16.3 micrograms FA/g (control), .5 microgram DON/g + 14.3 micrograms FA/g, 1.1 micrograms DON/g + 14.1 micrograms FA/g, and 1.9 micrograms DON/g + 13.6 micrograms FA/g. There was a significant linear reduction in feed intake after 1 wk with increasing levels of dietary DON. Weight gains declined significantly only after 3 wk. Increasing amounts of FA combined with relatively constant amounts of DON were fed in the third experiment. By analysis, diets contained .5 micrograms DON/g + 2.9 micrograms FA/g (control), 2.2 micrograms DON/g + 12.2 micrograms FA/g, 2.5 micrograms DON/g + 15.6 micrograms FA/g, and 2.4 micrograms DON/g + 15.9 micrograms FA/g. In the 1st wk, the feeding of increasing amounts of fusaric acid combined with a relatively constant amount of DON caused a significant linear depression in weight gain. We concluded that a toxicological synergism exists between DON and FA when fed to immature swine and that FA concentrations in feeds should be determined whenever DON analysis is conducted.

Preference of sheep and goats for extracts from high-grain concentrate

Appetite stimulants were extracted and partially isolated from high-grain concentrate. The stimulants were fed daily and were palatable to sheep and goats used in the experiments. The stimulative effects were tested by comparing the intake of two types of hay: with or without the extracts. Diethylether and n-pentane extracts of the concentrate stimulated feeding in sheep (P < .01 and P < .05, respectively). However, methanol extracts had no significant stimulative effect on selective feeding in sheep. Goats also preferentially fed on hay sprayed with the diethyl ether extracts (P < .01). The diethyl ether extracts were divided into acid, neutral, and basic fractions. Sheep and goats had a marked preference for the acid fraction only (P < .01 and P < .05, respectively). These results suggest that specific chemicals to increase palatability of hay are present in high-grain concentrate and that the chemical are nonpolar, acidic substances.

Factors affecting phosphorus and calcium digestibility in diets for growing-finishing pigs

In two experiments, we investigated various factors that affect the estimation of the apparent total tract digestibility (ATTD) of DM, Ca, and total P in diets for growing-finishing pigs. In Exp. 1, the effects of age, housing, and calculation method (indicator [Cr2O3] vs 10-d total collection) were determined. Eighteen barrows and gilts (40 to 95 kg BW) were housed in six pens, and ATTD was estimated using the indicator method. Twelve barrows were housed in metabolic crates, and ATTD was estimated using both calculation methods. Dietary treatments were 1) a tapioca-soybean-barley-based diet, 2) Diet 1 supplemented with 400 FTU microbial phytase/kg of diet, and 3) a corn-soybean meal-based diet: In Exp. 2, six barrows (95 to 120 kg BW) were fed a phytase-deficient diet to investigate the effects of coprophagy (40 g fresh feces/kg of diet) and movement. Pigs were fed at 2.8 times maintenance requirement (418 kJ ME/BW.75); water supply was 2.5 L/kg of feed. The ATTD increased as BW increased. Phytase enhanced total P ATTD by an average of 18.1 percentage units. The ATTD of DM was higher and the ATTD of Ca and total P (P < .001) were lower in pigs housed in pens than in pigs housed in metabolic crates. Fecal consumption and movement led to numerical increases in Ca (P = .217) and total P (P = .103) ATTD. Estimates of Ca and total P ATTD using pigs in metabolic crates are lower than estimates in practice.

Effect of forage:concentrate ratio on digestion and reproduction in primiparous beef heifers

We evaluated the effects of high- (HF) and moderate- (MF) forage diets on digestive and reproductive characteristics in beef heifers. Thirty primiparous beef heifers were allotted by weight and backfat thickness to receive either 80:20 (HF) or 50: 50 (MF) forage:concentrate ratio diets from parturition to at least 90 d postpartum. Alfalfa hay and wheat straw were the forage sources and barley was the concentrate source. Equal daily amounts of ME were provided to all heifers by restricting intake of the MF diet. Digestibility of DM was greater (P < .001) for MF compared with HF diets, whereas NDF digestibility was not different. Dry matter and NDF digested daily was lower (P < .001) for MF than for HF diets. Ruminal fluid pH was lower (P < .05) for MF diets; however, the acetate:propionate ratio was not different. Serum insulin concentrations were greater for MF diets for all hours (P < .001) and weeks (P < .05) of sampling. Changes in weight, backfat thickness, and body condition score at 90 d postpartum were not different between treatments. Calf gain to 30 d, however, was greater (P < .10) for the MF than for the HF treatment (25.5 vs 20.7 kg). Maximum size of the ovulatory follicle was greater (P < .10) for cows receiving the HF diet than for cows receiving the MF diet. However, other aspects of ovarian follicular growth and wave dynamics and the intervals from parturition to first and second ovulation, first estrus, first service, and conception were not different between treatments. Shifts in energy supply from forage to concentrate had minimal effect on digestion and reproduction in first-calf beef heifers in this study.

Energy evaluation of eight barley cultivars for poultry: effect of dietary enzyme addition

Three experiments were conducted to study eight barley cultivars and the effect of enzyme addition on their energy value for poultry. In Experiment 1, the AMEn of a reference barley (Beka cultivar) was calculated by increasing barley concentrations (30, 40, 50, and 60%) that replaced a high protein basal diet. In Experiment 2, eight barley cultivars (four spring and four winter cultivars) replaced the reference barley in the diet with 50% barley inclusion. Two of the winter cultivars were two-rowed and two were six-rowed cultivars. A commercial enzyme was added to these diets to study the effect of enzyme addition. Diets were consumed ad libitum by 27 and 145 21-d-old Arbor Acres broiler chicks, in Experiments 1 and 2, respectively. In Experiment 3, 66 adult roosters were used to determine the TMEn of the eight cultivars used in Experiment 2. Dietary AMEn decreased linearly (P < 0.05) with increasing barley (Beka cultivar) inclusion. Beka barley AMEn was calculated by extrapolation of the linear regression equation be equal to 2,980 kcal/kg DM. Barley energy value was influenced by cultivar (P < 0.001); the spring cultivars showed greater energy value than the winter cultivars (2,963 vs 2,852 kcal AMEn/kg DM; 3,192 vs 2,929 kcal TMEn/kg DM). Two-rowed cultivars showed higher TMEn than six-rowed winter cultivars, although no differences were found for AMEn. The correlation between AMEn and TMEn values of barley was relatively low (r = 0.69); therefore, barley TMEn cannot be extrapolated to AMEn for young chicks. Enzyme addition produced an average increase of 220 kcal/kg DM in barley AMEn (P < 0.001); there was a significant (P < 0.10) interaction between barley cultivar and enzyme supplementation. The increment of barley AMEn caused by enzyme addition was partly explained (47%) by an increase in barley viscosity. This relationship implies that enzyme supplementation significantly improves the feeding value of high as compared to low viscosity barley samples, which involved a decrease in AMEn variation among cultivars for enzyme-supplemented barley. No relationship was found between AMEn of unsupplemented barley cultivars and their chemical composition. Instead, a relationship was detected for enzyme-supplemented barley; therefore two equations were proposed for predicting the AMEn of enzyme-supplemented barley to be used directly in diet formulation.

Influence of flake density on the comparative feeding value of a barley-corn blend for feedlot cattle

Ninety-six medium-frame crossbred steers (209 kg) were used in an 86-d feeding trial. Dietary treatments consisted of a 92% concentrate diet containing 76.15% (DM basis) grain as 1) steam-flaked barley (SFB), flake density (FD) = .26 kg/L; 2) blend of 2/3 barley and 1/3 corn steam-flaked (SFBLEND), FD = .36 kg/L; 3) SFBLEND, FD = .31 kg/L; 4) SFBLEND, FD = .26 kg/L. There were no treatment effects (P > .10) on growth performance of feedlot steers or NE value of the diet. Weight gain averaged 1.46 kg/d. Feed efficiency was in close agreement (101%) with expected values based on observed DMI and tabular dietary NE values. Treatment effects on characteristics of ruminal and total tract digestion were evaluated using four Holstein steers (280 kg) with cannulas in the rumen and proximal duodenum in a 4 x 4 Latin square design. Ruminal digestibility of OM (P < .01), starch (P < .01), and feed N (P < .10) increased, and ruminal N efficiency (duodenal nonammonia N/N intake, P < .01) decreased (linear component) with decreasing FD. Net microbial N flow to the small intestine was greater (P < .05) for SFB than for the SFBLEND. Total tract digestion of OM (P < .01), starch (P < .05), and DE (P < .05) was greater for the SFBLEND than for SFB. There were no treatment effects (P < .10) on postruminal and total tract digestibility of N. We conclude that blending barley and corn before flaking will have very little impact on the feeding value of the grains compared with flaking the grains separately.

Influence of level of concentrate allocation and fermentability of forage fiber on chewing behavior and production of dairy cows

Nine midlactation dairy cows were offered one of three mixed silage rations with neutral detergent fiber (NDF) that was similar in concentration but different in fermentability. Differences in fermentability were achieved by substituting a high quality alfalfa silage for a low quality alfalfa silage and substituting a combination of ryegrass and timothy silages for a barley silage. In addition, concentrate was allocated at 0.30, 0.82, or 1.37 kg of dry matter/kg of dry matter intake (DMI) from the mixed silage ration. As expected, the NDF content of the mixed silage ration did not differ, although fermentability of NDF increased numerically as forage quality increased. Intake of NDF increased linearly, and DMI tended to increase linearly, as fiber fermentability of the mixed silage ration increased. In addition, cows produced more milk, milk fat, and milk protein and generated more total and milk energy. The calculated concentration of net energy for lactation of the total diet also increased. Results support the concept that NDF quality influences and can be used to predict voluntary feed intake, at least in relatively high producing dairy cows. The DMI increased, and intake of NDF and crude protein declined, as the allocation of concentrate increased. In addition, as concentrate allocation increased, cows spent less time eating and ruminating and more time resting and produced more milk, milk protein, and milk lactose. Cows also generated more total energy and milk energy, although, despite a sharp decrease in the forage proportion of the diet, the calculated energy density of the diet did not differ among concentrate levels. The lack of significant interactions between concentrate level and fiber fermentability for any parameter measured supports the contention that high quality forage is critical to a successful dairy ration, regardless of the proportion of forage in the diet.

The effect of grain source and grain processing on performance of feedlot cattle: a review

Effects of grain species and grain processing method on DMI, rate and efficiency of gain, and feeding value for cattle fed high concentrate diets were appraised by statistically compiling results from 605 comparisons from feeding trials published in North American journals and experiment station bulletins since 1974. Metabolizable energy (ME) values for each grain and processing method were calculated by quadratic procedures from DMI and animal performance. Averaged across processing methods, ME values for corn, milo, and wheat grain (3.40, 3.22, and 3.46 Mcal/kg DM) fell within 9% of ME estimates from NRC (1996) for beef cattle. In contrast, ME values for barley and oats grain (3.55 and 3.46 Mcal/kg DM) were 24% and 17% greater than NRC (1996) estimates. Compared with the dry rolled forms, high moisture corn and milo resulted in lower ADG and DMI. Compared with dry rolling, either steam rolling or flaking of corn, milo, and wheat decreased DMI without decreasing ADG and improved feed efficiency by 10, 15, and 10%, respectively. Compared with dry rolled grain, steam flaking increased (P < .05) body weight-adjusted ME of corn and milo grain by 15 and 21%, respectively; body weight-adjusted ME for whole corn was 9% greater (P < .05) than for rolled corn grain. Steam flaking was surprisingly effective (13%) at increasing (P < .05) the body weight-adjusted ME of wheat, but steam flaking failed to increase the ME of barley and oats. Higher moisture content of high-moisture corn decreased dry matter intake without depressing ADG and improved efficiency and increased ME of the grain. Compared with steam flakes of moderate thinness, processing milo or barley to a very thin flake tended to reduce ADG and failed to improve feed efficiency. The ideal roughage source and roughage moisture content for maximum ME and ADG varied with grain processing method. Feeding corn silage rather than alfalfa and wet rather than dry roughage depressed (P < .01) ADG of cattle and reduced (P < .01) body weight-adjusted ME of cattle fed high-moisture corn grain but tended to increase both with steam-flaked corn or wheat.

Influence of energy supplementation on grazing ruminants: requirements and responses

Energy requirements of grazing livestock seem to be poorly defined. Requirements generated from measurements in pen-fed animals present both theoretical and practical concerns when they are applied to grazing situations. In mature ruminants a majority of energy used for maintenance seems to be consumed by visceral tissues. Moreover, factors that affect visceral energy use are poorly understood. Energy supplementation to meet requirements and production demands is often practiced during periods of summer dormancy and in winter months. Source of supplemental energy varies widely and includes grains, readily digestible fiber sources, and high-quality forages. Intake and digestibility can be reduced or unaffected by energy supplementation. In some cases, lower levels of energy supplementation have been shown to increase utilization of grazed forage. Reductions in ruminal pH, often cited as the major cause of reduced fiber digestion, may not always explain reductions in intake and digestibility associated with energy supplementation. Livestock production is usually either enhanced or unaffected by energy supplementation. Additional research regarding energy requirements of grazing ruminants, visceral energy use, and mechanisms associated with reductions in intake and digestibility of grazed forage resulting from energy supplementation is warranted.

Source and amount of carbohydrate affect postprandial glucose and insulin in normal subjects

To determine if source and amount of carbohydrate affected postprandial glucose and insulin responses, seven nondiabetic subjects consumed 0, 25, 50, 75 or 100 g carbohydrate (total carbohydrate minus total dietary fiber) portions of barley, spaghetti, bread or potato. By ANOVA, both source and amount of carbohydrate had significant effects on incremental response areas for capillary glucose (P = 0.001), plasma glucose (P = 0.01) and plasma insulin (P = 0.03), but there was no source x amount interaction. By regression analysis, source of carbohydrate explained a similar amount of the variability of glucose and insulin responses, 46-64%, as the amount of carbohydrate, 47-57%. Together, carbohydrate source and amount accounted for 85-94% of the variability of mean glucose and insulin responses. We conclude that, for individual foods with different glycemic indices, both source and amount of carbohydrate influence the postprandial glucose and insulin responses of nondiabetic subjects.

The incidence of swine dysentery in pigs can be reduced by feeding diets that limit the amount of fermentable substrate entering the large intestine

Two experiments were conducted to test the hypothesis that feeding diets which limit the amount of fermentable substrate entering the large intestine would protect pigs against experimental infection with Serpulina hyodysenteriae, the causative agent of swine dysentery. Experiment 1 examined the effect of grain processing (hammer milling vs. steam flaking) and grain type (barley, groats, corn, sorghum and wheat) on indices of fermentation in the large intestine and the incidence of swine dysentery. Experiment 2 examined the role of five diets, steam-flaked corn, steam-flaked sorghum, hammer-milled wheat, extruded wheat and cooked white rice, on these same measures. All diets contained an animal protein supplement and no antibiotics. Pigs fed diets based on steam-flaked corn and steam-flaked sorghum had a lower incidence of disease (11-33%) than pigs fed diets based on other grains (75-100%). Pigs fed the diet based on cooked white rice were fully protected against swine dysentery. Both the soluble non-starch polysaccharide (NSP) concentration and the total NSP concentration of the diets explained a significant proportion of the variation in swine dysentery (R2 = 0.56, P = 0.016, and R2 = 0.71, P = 0.002, respectively), such that pigs eating diets containing <1.0 g/100 g soluble NSP showed reduced disease. However, pigs fed corn, sorghum and steam-flaked sorghum (Experiment 2), which contained only 0.4-0.5 g/100 g soluble NSP, still had a high incidence of disease (>50%). This was attributable to a higher level of resistant starch present in these grains. These data provide evidence that the expression of swine dysentery is associated with an increased concentration of fermentable substrate entering the large intestine.

Food preference and acceptance of novel foods by lambs depend on the composition of the basal diet

Ruminants eat a variety of foods, varying in toxins and nutrients, but no hypotheses adequately explain this behavior. We offer an explanation, one which encompasses avoidance of toxins and acquisition of nutrients. A key concept in this hypothesis is aversion, the decrease in preference for food just eaten as a result of sensory input (taste, odor, texture, i.e., a food's flavor) and postingestive effects (of toxins and nutrients on chemo-, osmo-, and mechano-receptors) unique to each food. On the basis of this hypothesis, we predicted lambs would prefer familiar and novel foods that complemented the macronutrient composition of their basal diet. To assess the validity of this prediction, we fed 10 lambs in each of three treatments different levels of ground barley (high in energy) and alfalfa (high in protein) as a basal diet. We then offered them daily a meal of three ground foods differing in proportions of barley and alfalfa (familiar foods) or wheat and rabbit pellets (novel foods). We found that lambs fed a basal diet high in energy (barley) preferred food lower in energy and higher in protein (alfalfa); those fed a diet high in alfalfa preferred food high in barley (P < .01). In addition, the higher the barley or alfalfa content of the basal diet, the greater the acceptance of novel foods high in alfalfa (i.e., rabbit pellets) or grain (i.e., wheat), respectively (P < .01). All lambs preferred foods high in wheat to rabbit pellets or alfalfa (P < 0.01), evidently because wheat is high in energy and it differs in flavor from barley, which was eaten repeatedly as part of the basal diet. On the basis of these results, we contend that lambs preferred familiar and novel foods that complemented the flavors and macro-nutrient contents of their basal diet.

Preference of sheep for foods varying in flavors and nutrients

Our objective was to better understand the importance of flavor and nutrients in food preferences of lambs. Three foods differing in flavor and nutritional quality were created by grinding and mixing grape pomace, barley, alfalfa pellets, and soybean meal in different proportions. food 1 (2.21 Mcal/kg DE, 8.1% DP), food 2 (2.42 Mcal/kg DE, 11.0% DP), and food 3 (2.68 Mcal/kg DE, 13.8% DP). Intake of each food, offered singly and together, was assessed when foods 2 and 3 were flavored with 1% onion or 1% oregano. Lambs (n = 24) preferred food 3 > 2 > 1, regardless of flavor (P < .05), and they continued to prefer food 3 > 2 > 1, even when they received the toxin LiCl after eating one of the three foods (P < .05). When offered a choice, lambs always ate substantial amounts of all three foods, even though they might have been expected to eat food 3 exclusively. We hypothesize selection of a varied diet resulted from a decrease in preference for food just eaten as a result of sensory input (taste, odor, texture, i.e., a food's flavor) and postingestive feedback (effects of nutrients and toxins on chemo-, osmo-, and mechano-receptors) unique to each food. Thus, we submit that offering different foods of similar nutritional value, offering foods of different nutritional value, and offering the same food in different flavors are all means of enhancing food preference and intake.

Barley varieties for finishing steers: I. Feedlot performance, in vivo diet digestion, and carcass characteristics

Eighty Angus x Hereford steers (average initial weight 287 kg) were used in a 168-d finishing study to evaluate the effects of barley variety on feedlot performance, diet digestion, and carcass characteristics. The four treatments compared in this completely randomized design (four pens/ treatment) were high-concentrate diets based on 1) corn, 2) Gunhilde barley (GUN), 3) Harrington barley (HAR), or 4) Medallion barley (MED). Steers consuming corn gained 10% faster (P < .01) than steers fed HAR, and HAR resulted in 8% faster (P < .01) gains than GUN or MED. Dry matter intake was greater (P < .01) for steers fed corn than for steers fed GUN, HAR, or MED, and HAR-fed steers consumed more than MED-fed steers. Efficiency (kilograms of gain/100 kg of feed) was higher (P < .05) for steers fed GUN, HAR, and MED than for corn-fed steers. Estimated NEm and NEg of barley varieties ranged from 2.32 to 2.51 Mcal of NEm/kg and 1.61 and 1.77 Mcal of NEg/kg. Carcass weight was greater (P < .01) for steers fed corn rather than HAR and greater (P < .01) for HAR-fed steers than for those fed GUN or MED. Quality grade was higher (P < .05) for HAR-fed steers than for steers fed corn, GUN, or MED. Steers fed corn had the highest (P < .01) digestible starch intake, followed by steers fed HAR, GUN, and, finally, MED, the same approximate ranking as for ADG. A diet based on Harrington barley resulted in greater DMI, ADG, and carcass quality grade compared with diets based on Gunhilde or Medallion barleys.

Barley varieties for finishing steers: II. Ruminal characteristics and rate, site, and extent of digestion

Four ruminally and abomasally cannulated steers were used to evaluate the effects of barely variety on rate, site, and extent of digestion of high-concentrate diets. The treatments compared were 1) corn, 2) Gunhilde barley (GUN), Harrington barley (HAR), and 4) Medallion barley (MED). Diets were balanced to be isocaloric and isonitrogenous. Ruminal OM digestion was greater (P = .04) in steers fed corn than in those fed GUN, HAR, and MED (61.9 vs average 53.7%). No differences (P > .10) were seen in ruminal starch digestion (average 92.8%) or in starch flow to the abomasum (average 199 g/d) between diets. Total tract digestion of starch was greater (P = .09) in steers fed barley than in those fed corn (average 98.6 vs 95.7%). Total and nonammonia N presented to the abomasum were greater (P < .05) for steers fed HAR and GUN than for those fed MED and corn. Microbial N flow was lowest (P = .01) in corn-fed steers, highest in steers fed GUN and HAR, and intermediate in steers fed MED. Microbial efficiency was 59% greater (P = .03) in steers fed barley than in steers consuming corn. Ruminal acetate: propionate was lower (P = .002) in steers fed corn and HAR than in those fed GUN and MED. Compared to GUN, HAR, and MED barleys, corn had a lower (P < .03) rate (-.11 vs average -.47) and extent (15 h; 70.3 vs average 98.1%) of in situ starch disappearance. Differences in digestive characteristics found between barley varieties may contribute to differences in animal performance.

Comparative feeding value of hulless vs covered barley for feedlot cattle

One hundred twenty medium-frame crossbred steers (364 kg) were used in a 106-d feedlot trial to compare the feeding value of Condor, a hulless barley (HB), with Leduc, a conventional covered barley (CB). Dietary treatments consisted of a finishing diet containing 77% grain (DM basis) as 1) steam-flaked corn (SFC); 2) dry-rolled HB (DRB-H); 3) steam-flaked HB (SFB-H); 4) dry-rolled CB (DRB-C); and 5) steam-flaked CB (SFB-C). Feed intake was lower (8.6%, P < .01) for HB than for CB. Diet NE was greater for HB than for CB (P < .01) and for SFB than for DRB (P < .01). Incidence of liver abscess was greater for DRB than for SFB (239%, P < .05) and for HB than for CB (167%, P < .10). Diet NE were greater (P < .10) for SFC than for barley treatments. Treatment effects on characteristics of digestion were evaluated using five Holstein steers (202 kg) with cannulas in the rumen and proximal duodenum. There were barley variety x grain processing interactions on ruminal digestion of OM (P < .10), ADF (P < .05), and starch (P < .05). Ruminal OM digestion increased (9.0%) with steam flaking HB and decreased slightly (1.9%) with steam flaking CB. Ruminal digestion of starch was enhanced more dramatically (21.5 vs 8.4%, respectively) with steam flaking HB than with CB. Steam flaking decreased ruminal ADF digestion of HB only slightly (6.2%), whereas with CB the decrease was more dramatic (54.3%). Ruminal degradable N was greater (P < .10) for CB than for HB and for DRB than for SFB (19.8%, P < .05). Estimates of ruminal degradable N in DRB-H, SFB-H, DRB-C, and SFB-C were 69.7, 53.9, 78.5, and 65.0%, respectively. Postruminal digestion of OM (P < .01), starch (P < .05), and N (P < .10) were greater for HB than for CB. Steam flaking barley increased (P < .01) postruminal N digestibility. Total tract digestibility of OM (P < .01), ADF (P < .05), starch (P < .01), and energy (P < .01) were greater for HB than for CB. Digestibility of ADF in barley hulls was only 6.4%. Steam flaking increased (P < .01) total tract digestibility of starch. Ruminal digestibility of OM and feed N was lower (P < .01) for SFC than for barley diets. Ruminal pH was lower (P < .10) for HB than for CB and for SFB than for DRB (P < .01). Ruminal propionate was higher (24.1%, P < .01), and methane was lower (17.9%, P < .01) for HB than for CB.

The effects of physical form of feed, carbohydrate source, and inclusion of sodium bicarbonate on the diet selections of sheep

We proposed an hypothesis that ruminants attempt to select a diet that promotes high levels of feed intake by maintaining optimal ruminal conditions. Three tests of the hypothesis considered whether the diet selection of sheep given either a choice of two high energy density (ED) feeds or a choice between a high and a low ED feed is affected by 1) sodium bicarbonate inclusion (NaHCO3; 1, 2, and 4% [wt/wt]) in the high [ED] feed); 2) dietary carbohydrate source (barley-based, B and sugar beet/ barley, S) of the high ED feed; or 3) physical form (alfalfa: pelleted, ALFP and long chop, ALFL) of the low ED feed. To conduct these, 42 lambs were used in seven 6 x 6 Latin squares, which were either foods ALFL and ALFP offered alone and paired with feed B or S and their NaHCO3 derivatives as a choice, or foods B and S offered alone and paired with their NaHCO3 derivatives as a choice. Each Latin square period lasted for 3 wk. For the choices between a NaHCO3-supplemented high ED feed and either a high or a low ED one, the inclusion of NaHCO3 increased feed intake. Its level of inclusion had a marked effect on the proportion of unsupplemented high ED feed selected (P < .05) but not on the proportion of low ED feed (alfalfa) selected. More alfalfa was selected when the high ED feed was based on barley (B) rather than sugar beet/barley (S) (P < .05). The physical form of the alfalfa affected diet selection because its selection was greater (P < .001) when ALFP (pelleted) was offered in the feed choice rather than ALFL (long-chop). The significant effects of NaHCO3 level, dietary carbohydrate, and physical form on the diet selection and feed intake of the sheep are consistent with the proposed experimental hypothesis.

The influence of dietary salt level on water consumption, farrowing, and reproductive performance of lactating sows

During two consecutive lactations using a switch-back design, 16 sows received a corn, cassava, barley, and soybean meal diet supplemented with either 8.5 or 1 g/kg of NaCl (.4% Na or .1% Na, respectively). The average daily water consumption during the 4-wk lactation period was greater (P < .01) for the sows fed the high-salt diet than for those fed the low-salt diet (13.9 vs 12.4 L, respectively). Urine production accounted for 27% of the water intake during lactation. This resulted in a difference during the entire lactation period of 42.2 L in water consumption (P = .07) and 11.4 L in urine production (P = .07). The Na and Cl concentrations of the urine for sows fed the high-salt diet were higher than for sows fed the low-salt diet (P < .05), but the K, Mg, P, and Ca concentrations were not influenced. The milk composition, measured at d 1, 13, and 27 of lactation, was relatively independent of the dietary salt level, except for the Cl concentration at d 1 after farrowing, which was higher (P < .05) for sows fed the high-salt diet. The moisture and ash content of the milk increased with the length of the lactation, irrespective of the diet. The increased ash content on d 13 and 27 of lactation was accounted for by the increased concentrations of P and Ca. There was no effect of dietary salt level on weight change of the sow or on the growth performance of the pigs. The interval from weaning to estrus (n = 13, t = 2.48, P = .029) was shorter for sows fed the high-salt diet than for sows fed the low-salt diet (6.2 +/- 1.0 and 12.6 +/- 3.1 d, respectively). More sows were unsuccessfully mated after receiving the low-salt diet during lactation. These results indicate that a low-salt diet for lactating sows results in lower water consumption, lower urine production, and lower Na and Cl concentrations in the urine. Milk composition, weight change of the sow, and growth performance of the pigs were not altered, but reproductive failures afterward may point to a salt deficiency during lactation.

Influence of sampling time and diet on amino acid composition of protozoal and bacterial fractions from bovine ruminal contents

Four ruminally cannulated cows were used to compare amino acid (AA) composition of protozoal and bacterial fractions as affected by sampling time and diet. Cows were given once a day restricted feed (80% of ad libitum intake) of 7 kg DM with two successive diets. Diet HB was 65% Cocksfoot hay and 35% pelleted ground barley, and Diet H was 100% Cocksfoot hay. Samples of whole ruminal contents were taken 2, 5, 8, 11, and 23 h after feeding for Diet HB and 2 h after feeding for Diet H to isolate the liquid-associated protozoa and bacteria (LAP, LAB) and particle-associated bacteria (PAB). At each sampling time, the AA compositions of the different microbial populations were determined. The AA profiles of the LAP were different from those of the bacteria for 13 AA out of 17 studied. Differences between AA compositions of LAB and PAB were also observed for 10 AA out of 17 studied. Irrespective of the microbial population, AA composition did not vary with sampling time after feeding diet HB (P > .05; except for arginine, glutamate, and glycine). The AA contents of none of the three microbial populations were affected (P > .05) by the diet except for leucine and glutamate (P < .01). The differences in AA profiles between LAP and bacteria and between LAB and PAB confirm the importance of the representativeness of the microbial reference sample for correctly estimating microbial AA flow into the small intestine.

Influence of Trichoderma viride enzyme complex on nutrient utilization and performance of laying hens in diets with and without antibiotic supplementation

The experiment was designed to test possible interactions of an enzyme complex (product from Trichoderma viride) and a feed antibiotic (flavophospholipol) in a barley diet on metabolism variables and egg production performance of Warren Brown laying hens. The basal diet contained 40% winter barley (French cultivar "Express", six row). The four treatments were as follows: O, control (without supplement); E, enzyme complex, 600 ppm; A, flavophospholipol, 10 ppm; EA, enzyme complex, 600 ppm and flavophospholipol, 10 ppm. The enzyme complex contained the following main activities: cellulase (10,500 U/g), endo-beta-(1:3)(1:4)-glucanase (24,000 U/g), and xylanase (32,000 U/g). The enzyme positively influenced AME content of the feed, organic matter (OM) utilization, and neutral detergent fiber (NDF) degradability (P < or = 0.01). When supplemented alone, the antibiotic had no influence on energy and nutrient utilization. No significant differences in egg production due to dietary treatments were observed. A significant enzyme by antibiotic interaction for AME (P < or = 0.01) and OM utilization (P < or = 0.001) as well as NDF degradability (P < or = 0.01) indicated a reduced enzyme effect in the diet containing antibiotic. Negative enzyme by antibiotic interaction for energy utilization in laying hens suggested that the positive response to dietary enzyme supplementation in the mature laying hen (Treatment O vs E) was to great extent mediated by the activity of intestinal microbes.

Products based on a high fiber barley genotype, but not on common barley or oats, lower postprandial glucose and insulin responses in healthy humans

Postprandial blood glucose and insulin responses to cereal products made from common barley, oats or a barley genotype containing elevated levels of beta-glucans were evaluated in nine healthy subjects. Porridges were made from commercial Swedish whole-meal barley or oat flours, and a mixed whole-meal porridge using the high fiber barley genotype and commercial Swedish common barley (50:50). Also studied were two types of flour-based bread products composed of high fiber barley and common barley in ratios of 50:50 or 80:20, respectively. The common oat and barley porridges produced postprandial glucose and insulin responses similar to the white wheat bread reference, suggesting that the naturally occurring dietary fiber in these whole-meal flours has no impact on the glucose tolerance. In contrast, all high fiber barley products induced significantly lower responses than did the reference product, with the glycemic and insulin indices ranging from 57 to 72 or 42 to 72%, respectively. It is concluded that "lente" products of high sensory quality can be prepared from a barley genotype with an elevated content of soluble dietary fiber. The glycemic index of these products compares favorably with that of products made from common cereals, suggesting their use as a potential component of diets for patients with diabetes and hyperlipidemia, and for individuals predisposed to metabolic disease.

Effects of barley variety and processing methods on feedlot steer performance and carcass characteristics

An experiment was conducted to evaluate ammoniation and temper processing of two barley varieties of diverse types on feedlot cattle performance and diet digestibility. Steptoe (feed variety) and Klages (malting variety) barleys were processed as dry-rolled (DR); tempered and rolled (TR); tempered, ammoniated, and rolled (AR); and tempered, ammoniated, and fed whole (AW). Crossbred steers (n = 240, initial weight 266 kg) were blocked by weight and randomly assigned to one of eight treatments in a 2 x 4 factorial arrangement. Diets contained 30% barley (DM basis) for the growing phase and 85% (DM basis) for the finishing phase. Growing phase ADG and gain to feed (G/F) were less (P < .05) for AW than for DR, TR, and AR. Average daily gain was less (P < .05) for AW than for TR and AR in the finishing phase. There were no differences (P > .05) in ADG or G/F between DR, TR, and AR during growing or finishing phases. Gain to feed was greater (P < .05) for TR and AR than for AW but not for DR for the total trial. Hot carcass weight, longissimus muscle area, and kidney-pelvic-heart fat were greater (P < .05) for TR and AR than for AW. Total finishing diet ADF digestibility was greater (P < .05) for Steptoe than for Klages (40.5 vs 31.4%, respectively). The DR treatment had the lowest ADF digestibility, whereas AR had the greatest (P < .05). Results suggest that there were no differences in feedlot steer performance due to barley varieties of the same bulk density and that barley grain must be mechanically processed for optimal performance response rather than ammoniated and fed as whole grain.

Effect of barley variety and dietary barley content on digestive function in beef steers fed grass hay-based diets

Five ruminally and duodenally cannulated steers were used in a 5 x 5 Latin square design with a 2 x 2 + 1 arrangement of treatments to study the effects of barley variety and dietary barley content on digestive function in steers fed grass hay-based diets. Barley varities evaluated were Russell and Steptoe, which had bulk densities of 67.7 and 64.5 kg/hL, respectively. Supplemental treatments were as follows: corn, low Russell (Ru-lo), low Steptoe (St-lo), high Russell (Ru-hi), and high Steptoe (St-hi). Corn, Ru-lo, and St-lo were provided at 30% (DM basis) of grass hay-based diets, whereas Ru-hi and St-hi were provided at 35.5% of diet DM (equal starch content as the corn treatment). No treatment differences (P > .10) were observed for DMI, ruminal particulate passage rate, and NDF total tract digestibility. Ruminal DM and starch digestibility were greater (P < .01) for barley-containing diets than for the corn diet. Similarly, total tract DM (P < .10) and starch (P < .01) digestibility was greater for barley than for corn diets. Microbial protein and non-NH3 N flow to the small intestine were greater (P < .01) for the barley diets than for the corn diet. Starch intake (P < .01) and DM digestibility (P < .10) were greater for high- than for low-barley diets; however, differences due to barley variety were not observed (P > .10). In situ disappearance of grass hay NDF at 8 and 96 h of incubation was greater (P < .05) for barley than for corn diets. Rate of in situ disappearance of grain DM was greater (P < .01) for barley than for corn and for Russell than for Steptoe barley. Responses suggest that ruminal and total tract digestibility and protein flow to the small intestine can be increased with barley compared with corn as an energy supplement to grass hay-based diets.

Influence of energy or protein supplementation during midpregnancy on forage intake of ewes grazing Montana winter range

A 2-yr winter experiment was conducted to determine the influence of either energy or protein supplementation during midpregnancy on fecal output (FO), forage intake, blood metabolite profiles, and BW changes of ewes grazing winter range. Thirty-two Targhee ewes were selected for uniformity in age and BW and assigned randomly to one of four dietary treatments 1) no supplement (NONE); 2) 150 g of barley supplement (BAR); 3) 75 of feather g meal, blood supplement (FM/BM); and 4) 75 g of FM, BM, urea supplement (FM/BU/U). Two 5-d experimental periods were conducted during each winter (January and February). Forage FO (P = 0.9), total FO (P = 0.7), and subsequent forage intake (P < .01) were higher during Yr 1 than during Yr 2. Supplement type did not affect forage DMI when expressed either as grams/day (P = .57) or as a percentage of BW (P = .52). Body weight changes and body condition scores were not affected (P > .10) by year but were affected (P < .01) by treatment; unsupplemented ewes lost more (P < .01) BW and body condition than supplemented ewes. Serum urea N (SUN) concentrations were affected (P < .03) by a year x treatment interaction. Unsupplemented, FM/ BM, and FM/BM/U ewes had higher (P < .10) SUN concentrations during Yr 1 than during Yr 2, averaging 9.8 ml/dL and 7.5 mg/dL, respectively. Barley-supplemented ewes had similar (P > .10) SUN concentrations both years, averaging 7.4 mg/dL. Alternate-day supplementation during midpregnancy with energy of protein had no effect on forage DMI of ewes grazing winter range.

Growth, viscosity and beta-glucanase activity of intestinal fluid in broiler chickens fed on barley-based diets with or without exogenous beta-glucanase

1. Three groups of birds were fed for up to 35 days on diets containing 500 g barley (cv. Condor)/kg diet, with or without exogenous beta-glucanase, either a commercial preparation or a recombinant endoglucanase. 2. Birds which received diets containing the exogenous enzymes grew faster for the first 3 weeks but after that there was no apparent difference in rate of growth. 3. beta-Glucanase activities in the crop and small intestine of birds given exogenous enzymes were generally higher than those of birds given only the basal diet. 4. Viscosity of intestinal fluid in birds given only the basal diet decreased with age but there was no corresponding increase in beta-glucanase activity. This discounts bacterial beta-glucanase as a contributory factor in the adaptation to beta-glucanase apparent in older birds.

Sourdough fermentation or addition of organic acids or corresponding salts to bread improves nutritional properties of starch in healthy humans

Postprandial blood glucose and insulin responses to barley bread containing organic acids or corresponding salts were evaluated in healthy human subjects. The satiety score and the rate and extent of in vitro starch digestion were also studied. Lactic acid was generated by use of a homofermentative starter culture or added to the dough. In addition, products were baked with Ca-lactate, or with Na-propionate at two different concentrations. Consumption of the product baked with a high concentration of Na-propionate significantly lowered the postprandial blood glucose and insulin responses, and significantly prolonged the duration of satiety compared with all other breads. When subjects consumed the breads baked with sourdough, lactic acid and Na-propionate, their glucose and insulin responses were reduced compared with the wholemeal bread alone. The rate of in vitro amylolysis was reduced only by ingestion of the breads containing lactic acid, suggesting that the beneficial impact of Na-propionate on metabolic responses and satiety was related to effects other than a reduced rate of starch hydrolysis. All bread products had a similar concentration of in vitro resistant starch of 1.3-2.1 g/100 g (starch basis). It is concluded that sourdough baking and other fermentation processes may improve the nutritional features of starch. The results also demonstrate that certain salts of organic acids may have metabolic effects.

Different strains of Saccharomyces cerevisiae differ in their effects on ruminal bacterial numbers in vitro and in sheep

A ruminal simulation device (Rusitec) was used to compare the effects of Saccharomyces cerevisiae strains NCYC 240, NCYC 694, NCYC 1026, NCYC 1088, and Yea-Sacc (a commercial product containing S. cerevisiae) on ruminal fermentation. S. cerevisiae NCYC 240, NCYC 1088, NCYC 1026, and NCYC 694 were grown on malt extract at 30 degrees C in aerated fed-batch culture and harvested along with spent growth medium by freeze-drying. Each vessel received daily 20 g of a basal diet consisting of hay, barley, molasses, fishmeal, and a minerals/vitamins mixture at 500, 299.5, 100, 91, and 9.5 g/kg of DM, respectively. Yeast preparations (500 mg/d) were added along with the feed. S. cerevisiae NCYC 240, NCYC 1026, and Yea-Sacc stimulated total and cellulolytic bacterial numbers, whereas S. cerevisiae NCYC 694 and NCYC 1088 had no effect on the numbers of bacteria. The effects of S. cerevisiae NCYC 240, NCYC 1026, and Yea-Sacc on ruminal fermentation were further investigated in vivo using ruminally cannulated sheep fed 1.5 kg/d of the diet used in Rusitec, supplemented with 2 g/d of yeast culture. All treatments tended to stimulate total and cellulolytic bacterial numbers. However, the stimulation was only statistically significant for S. cerevisiae NCYC 1026 with total bacterial numbers and S. cerevisiae NCYC 240 with cellulolytic bacteria (P < .05). Increased bacterial numbers were associated with an increase in the rate of straw degradation in the rumen and a nonsignificant (P > .05) increase in the excretion of purine derivatives in the urine, measured as an index of microbial nitrogen leaving the rumen.(ABSTRACT TRUNCATED AT 250 WORDS)

[A preliminary study of the components causing poor utilization of barley in the young chicken]

The effect of barley on the characteristics of the intestinal contents and on the growth performance has been studied in the young chicken (5 to 27 days) by comparing 5 different varieties of barley: 2 six-rowed winter barleys (Astrix and Sympa)), 2 two-rowed winter barleys (Alpha and Sonja) and 1 two-rowed spring barley (Aramir). All the barleys were used in the ration at a rate of 50 p. 100 to constitute 5 complete, balanced diets which were similar (e.g. energetic value, amino acids) to each other and to a control diet of corn and soya. There was no relation between the characteristics (in particular, viscosity of barley soluble components) of the barleys studied in this trial and the growth performances obtained. On the other hand, the 2 barleys (Astrix and Alpha) which caused retarded growth and a significant increase in the conversion rate were the same ones modifying the viscosity of the intestinal contents. The barley intolerance of the young chicken is thus related to the presence of undigestible, viscous components which are difficult to determine by a simple water extraction of the barley.

Nutritional evaluation of wheat and barley cultivars by growth rate and body composition of larvae of Tenebrio molitor

Larvae of the yellow mealworm, Tenebrio molitor L., Gembloux strain, race F, were reared on diets of 17 cultivars of wheat and 29 cultivars of barley, prepared for determination of digestible energy with mice, for 4 weeks at 27 +/- 0.25 degrees C and 65 +/- 5% relative humidity. Values for percentage crude protein of tissues of larvae fed wheat cultivars were significantly and positively correlated with values for digestible energy as determined with mice. These values were not correlated for larvae fed barley cultivars; however, values for per cent dry matter content of larvae were significantly and positively correlated with values for digestible energy determined with mice. This apparent discrepancy is explained on the basis of the chemical constitution of barley and the availability of amino acids of barley to the larvae. Use of larvae of Tenebrio molitor to indicate the digestible energy of cereal grains is feasible, provided that the proper parameter is chosen. Nevertheless, use of this biological method seems more suitable for evaluation of protein quality and of amino acid availability than for a measure of digestible energy of feeds.