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.

Preference for flavored wheat straw by lambs conditioned with intraruminal administrations of sodium propionate

We hypothesized that volatile fatty acids are feedback signals that condition food preferences in ruminants, and we tested two predictions based on this hypothesis: 1) low doses of propionate condition preferences for low-quality foods (Exp. 1 and 2) preferences are not caused by osmotic load (Exp. 2). In Exp. 1, lambs were offered chopped wheat straw flavored with either oregano or onion on odd days, whereas on even days flavors were switched and lambs received capsules containing sodium propionate. During four 8-d conditioning periods, the amounts of propionate delivered ranged from .7 to 1.4% of the daily DE intake (Period 1) or were fixed at .7% (Period 2) and 1% of the daily DE intake (Periods 3 and 4). After each 8-d conditioning period, lambs were offered oregano- and onion-flavored straw. Conditioning was then suspended and lambs were offered onion- and oregano-flavored straw at weekly intervals for 1 mo (extinction). Lambs preferred the flavor paired with propionate during conditioning (P < .001) and extinction (P < .07). During Exp. 2, a different group of lambs was conditioned as in Exp. 1, but sodium chloride was delivered at osmotic loads equivalent to those when propionate supplied .7% and 1% of the daily DE intake. Lambs strongly avoided the flavor paired with sodium chloride (P < .001). Thus, lambs acquired preferences for straw conditioned with doses of propionate typically considered ineffective in the regulation of food intake, and osmolalities generated by propionate did not cause, but probably attenuated, food preferences.

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.

Supplemental cracked corn or wheat bran for steers grazing endophyte-free fescue pasture: effects on live weight gain, nutrient quality, forage intake, particulate and fluid kinetics, ruminal fermentation, and digestion

Two experiments were conducted with beef steers (Exp. 1, average BW of 580 kg; Exp. 2, average BW of 247 kg) to evaluate the use of no supplements (CON) or daily supplementation with (OM basis) .34% of BW of cracked corn (CORN), .34% of BW of wheat bran (WBBW), or .48% of BW of wheat bran (WBISO; calculated to be isocaloric to CORN) on digestive responses (Exp. 1) and live weight gain (Exp. 2). In Exp. 1, type of supplement did not affect (P > .10) the dietary fiber or N constituents, but in vitro OM disappearance of the forage differed (P < .10) with supplementation and type of supplement fed. Supplemented steers consumed less (P < .05) forage and total OM. Particulate passage, fluid passage, and ruminal pH were not affected (P > .10) by supplementation. Ruminal NH3 N concentration showed (P < .05) a treatment x sampling time interaction and, in general, WBBW and WBISO steers had greater ruminal NH3 N than CORN and CON steers. Total VFA concentrations and molar proportions of propionate were lower (P < .10) in CON steers than in supplemented steers; no differences were noted (P > .10) among supplemented steers. Molar proportions of acetate were lower (P = .01) in supplemented steers than in CON steers and were greater (P = .03) in WBBW steers than in WBISO steers. Butyrate molar proportions were lower (P < .05) in CON steers than in supplemented steers and differed (P < .10) with type and quantity of supplement supplied. In situ forage NDF disappearance at 6, 9, and 24 h after feeding and rate of disappearance were greater (P < .05) in CON steers than in supplemented steers. In Exp. 2, CON steers weighed less (P = .01) than supplemented steers, CORN steers weighed more (P = .08) than wheat bran-supplemented steers, and WBISO steers weighed more (P = .02) than WBBW steers; ADG for 90 d followed a similar response. Results suggest that supplementation of wheat bran rather than corn did not seem to stop the reduction in forage intake or OM digestion associated with corn supplementation.

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.

Effects of dietary concentrate level on nutrient absorption, liver metabolism, and urea kinetics of beef steers fed isonitrogenous and isoenergetic diets

Six multicatheterized beef steers (421 +/- 21 kg BW) were used to predict the effect of dietary concentrate level on blood flow and net flux of urea and other metabolites across splanchnic tissues. Diets ranged from 0% (switchgrass hay) to 90% concentrate (10% switchgrass hay, 89% cracked corn, 1% urea). Daily DMI varied from 8.01 to 5.34 kg/d. Nitrogen intake (99 g/d) and calculated ME intake (16.8 Mcal/d) were equal among diets. As dietary concentrate increased from 0 to 90%, liver blood flow decreased from 850 to 795 L/h, portal-drained visceral (PDV) blood flow decreased from 750 to 620 L/h, and mesenteric-drained visceral (MDV) blood flow decreased from 270 to 250 L/h. Liver release of urea N was 94 mmol/h when dietary concentrate was less than 20%, then increased to 146 mmol/h at 55% concentrate. Urinary excretion of urea N was 13 mmol/h or less when dietary concentrate was 20% or less, increased to 53 mmol/h at 55% concentrate, then continued to increase to 76 mmol/h at 90% concentrate. Transfer of urea N to PDV ranged from 71 to 91 mmol/h and transfer to MDV ranged from 0 to 10 mmol/h among diets. As dietary concentrate increased from 27 to 63%, VFA release by PDV decreased, net MDV and splanchnic release of glucose increased, and splanchnic tissues switched from net uptake to net release of L-lactate. Net PDV release or liver removal of ammonia or alpha-amino N and net liver release of glucose were not affected. We conclude that the liver responded to changes in the percentage of dietary concentrate by altering urea production and by altering the role of lactate in intermediary metabolism.

Spent cellulose casings as potential feed ingredients for ruminants

Cellulose casings are used to contain and form meat and poultry emulsions during the smoking and cooking process. Casings then are stripped from the cooked product and traditionally disposed of in landfills. Because of the bulk of the spent cellulose casings (SCC), rapid composting technology may be used to reduce bulkiness. The following SCC were evaluated in vitro and in vivo: fibrous ground (FG), fibrous composted (FC), NOJAX ground (NG), and NOJAX composted (NC). In vitro digestibility was determined by incubating SCC with mixed ruminal bacteria for 0, 6, 12, 24, 36, 48, and 72 h. In vivo data were collected using four ruminally cannulated Holstein steers in a 4 x 4 Latin square design. Diets consisted of a 50:50 ratio of alfalfa hay-wheat middlings with 5% cornsteep liquor. Diets contained no SCC (CON) or 25% (DM basis) of the FC, FG, or NC SCC substrate. Casings were high in structural carbohydrate and salt content but low in CP, ether extract, and lignin concentrations. In vitro OM digestibility at 24 h was highest (P < .05) for FC and lowest (P < .05) for NG; FG and NC were intermediate. Composting tended to reduce fiber content and increase digestion. In vivo intakes and digestibilities were not adversely affected by inclusion of SCC in the diet. Thus, SCC have the ability to partially replace more traditional forages, such as alfalfa hay and wheat middlings, in high-fiber diets for growing beef cattle. Limitations in the use of SCC as a partial replacement of traditional feedstuffs will likely be because of high salt concentrations in the casings resulting from product brine chilling.

Crystalline lysine and threonine supplementation of soft red winter wheat or triticale, low-protein diets for growing-finishing swine

Five trials, with five treatments each, involving a total of 240 pigs were conducted to evaluate the effectiveness of supplementation of soft red winter wheat- or triticale-based diets with crystalline lysine and threonine for growing and finishing pigs (25 to 110 kg). Within each trial, wheat- or triticale-based diets were supplemented with soybean meal to meet the requirement of the first- (lysine) or third- (isoleucine/methionine + cystine) limiting amino acid. Diets formulated to the third-limiting amino acid also were supplemented with feed grade L-lysine. HCl and L-threonine to meet the requirements of the first- and second-limiting amino acids. A cornsoybean meal diet was included in each trial as a positive control treatment resulting in the five dietary treatments. Three different crop years of soft red winter wheat and triticale were utilized. Three of the trials, conducted in successive years with each using a different crop year of grain, were done at Marianna, and the other two, conducted in successive years using yr 1 and 2 crops, respectively, were done at Gainesville. In all trials, growing diets (.82% lysine) were fed from 29 (Marianna) or 25 kg (Gainesville) to 55 kg average BW and finishing diets (.64% lysine) to 110 or 100 kg. Over the three crop years, the wheat and triticale averaged 11.3 and 11.0% crude protein, .36 and .38% lysine, and .36 and .37% threonine, respectively. Overall, at either location, growth rate and carcass lean content were not affected by grain source (P > .10). At Marianna, gain:feed was 2 to 3% lower for pigs fed the triticale diets than for pigs fed wheat (P = .15) or corn (P < .10); gain:feed was not affected by grain source at Gainesville (P > .10). At both locations, substantial replacement of soybean meal protein with crystalline lysine and threonine did not affect pig growth or carcass lean content (P > .10), even when the diet contained very little or no soybean meal as occurred for finishing pigs (55 to 110 kg) fed diets containing triticale.

A simple model for predicting the response of chicks to dietary enzyme supplementation

Two experiments with Leghorn chicks and data from five publications were analyzed to determine whether a simple general equation could be used to predict the relationship between the amount of a crude enzyme added to a diet and chick performance. The maximum improvements in weight gain and feed: gain ratio in Leghorn chicks fed rye diets containing different concentrations of enzymes were as high as 61 and 42%, respectively. Regression analyses demonstrated that there was usually a high linear correlation (r2 > 0.9, P < 0.05) between the concentration of the enzyme when transformed into its logarithmic value and weight gain or the feed:gain ratio. The general prediction equation was Y = A + B(logX), where Y is the performance value (i.e., weight gain, grams), A is the intercept (y-axis), B is the slope of the line (change in performance per units of enzyme in the diet), and X is the amount of enzyme in the diet. The slope of the line provides an index of the overall efficacy of the enzyme treatment. The log-linear model shows that for every ninefold increase in amount of enzyme in the diet (i.e., when the amount was increased to 10 times the starting amount), there was only a doubling of improvement in chick performance. High correlations (r2 values) were also obtained when data from the literature were analyzed. The equation was applicable to different classes and ages of poultry fed diets containing rye, wheat, barley, and lupins. These studies demonstrate that there is a linear relationship between the amount of enzyme added to the diet, when expressed as a logarithmic value, and the corresponding performance of chickens.

Wheat bran abolishes the inverse relationship between calcium load size and absorption fraction in women

Fractional calcium absorption from varying intakes of calcium carbonate co-ingested with wheat bran, as well as alone, was measured in a randomized crossover study in healthy adult women. The calcium carbonate was intrinsically labeled with 45Ca. Absorption from the carbonate, ingested without bran, showed the expected inverse relationship to the logarithm of ingested load size (slope = -0.1199; not substantially different from the value previously reported for milk). At 0.5 mmol calcium load, fractional absorption averaged 0.769 +/- 0.134, whereas at 12.5 mmol load it averaged 0.378 +/- 0.069. In contrast, fractional absorption from calcium carbonate co-ingested with 40 g of a cereal product containing 16 g wheat bran, across a calcium load range from 0.5 to 15.5 mmol, was essentially constant (mean for all loads: 0.230 +/- 0.069). Thus, the calcium-binding capacity of the bran cereal altered the usual inverse relationship between calcium load and fractional absorption. In vitro calcium binding to the bran cereal was linear over a wide range of calcium levels. This suggests that binding of calcium to one or more components of the bran cereal is sufficient to explain the reduced absorption demonstrated in vivo.

Effect of sesame seed proteins supplementation on the nutritional, physical, chemical and sensory properties of wheat flour bread

Sesame products (sesame meal, roasted and autoclaved sesame meal, sesame protein isolate and concentrate) were added to Red wheat flour to produce blends at protein levels of 14, 16, 18 and 20 percent. Dough properties were studied using a Brabender Farinograph. Loaves were prepared from the various blends using the straight dough procedure and then evaluated for volume, crust and crumb colour, crumb texture, flavour and overall quality. The water absorption, development time and dough weakening were increased (p < 0.05) as the protein level increased in all blends; however, dough stability decreased. Sesame products could be added to wheat flour up to 18 percent protein level (sesame protein isolate) and up to 16 percent protein level (other sesame products) without any observed detrimental effect on bread sensory properties. No significant differences (p > 0.05) were recorded in loaf volume between control and breads containing sesame protein isolate (up to 18 percent protein level) and either autoclaved sesame meal or sesame protein concentrate (up to 14 percent protein level). Addition of sesame products increased the content not only of protein but also minerals and total essential amino acids, especially lysine. The addition also improved in-vitro protein digestibility.

Effects of fill volume of diets on digestive tract kinetics and fattening pattern of growing Holstein-Friesian bull calves

Young Holstein-Friesian bull calves were tested in three trials for their performance and digestive tract kinetic responses to diets differing in their fill volume (FV) in the digestive tract. In Trial 1, a high ME (11.7 MJ/kg of DM) diet was compared with three medium ME (10.5 MJ/kg of DM) diets, one of high FV and two of low FV. In Trial 2, two silages (wheat and sorghum), differing in FV, were compared with or without poultry litter inclusion. All the diets in this trial had the same ME content of 10.5 MJ/kg of DM. Rate of gain, DM and ME intake, and depot fat percentage at slaughter were recorded. In Trial 3, two diets (high and low FV) and the same ME content of 10.4 MJ/kg of DM were compared in a short-term trial for digestive tract kinetics using a single dose of Cr-NDF and Co-EDTA as particulate and solute markers, respectively. Calves in Trial 1 fed medium ME and low FV diets had higher (not significant) DMI than high ME calves but similar ADG, whereas medium ME and high FV calves had the lowest DMI (P < .1) and ADG (P < .05). Low FV and medium ME calves were leaner (P < .05) at slaughter than the high ME calves and fatter (not significant) than the high FV and medium ME calves. In Trial 2, reduction of FV by silage replacement increased DMI (P < .01) and ADG (P < .05). Incorporation of poultry litter into the diets resulted in effects in the same direction (not significant). Such a reduction caused increased (P < .01 for both silage end poultry litter effects) deposition of cod fat in the carcass. Mean retention time estimations in Trial 3 indicated increased (P = .055) particle retention time in the low FV calves, compared to the high FV calves. This increase was due to a longer (P = .1) stay of particles in the lower parts of the digestive tract, and not in the rumen. Lowering the FV of medium ME diets increased DMI of calves to support ADG equal to that of a high ME diet, but with a lower fat accumulation.

Protein supplementation of ammoniated wheat straw: effect on performance and forage utilization of beef cattle

We studied the effects of supplement CP concentration on performance and forage use of cattle allowed ad libitum access to ammoniated wheat straw. During two consecutive winters, crossbred beef cows in late gestation (n = 87 in 1990-1991, n = 84 in 1991-1992) were used in a randomized complete block design with three pens per treatment. Cows were stratified by weight, body condition score (BCS), age, and breed and randomly assigned within strata to 1) control (C, no supplement), or 2 kg/d of 2) low-protein (LP) supplement (12% CP), 3) moderate-protein (MP) supplement (20.1% CP), or 4) high-protein (HP) supplement (31.7% CP) (DM basis). The feeding period was 84 d in 1990-1991 and 60 d in 1991-1992. Supplementation (C vs LP, MP, or HP) increased (P < .01) cow weight gains (32.7 vs 60.7, 62.8, and 72.4 kg, respectively) and improved (P < .01) BCS. Calf birth weights, weaning weights, and ADG were not affected by treatment (P > or = .20). Average calving date, percentage of cows cycling at the start of the breeding season and percentage pregnant after a 60-d breeding season were also similar (P > .20) among treatments. Sixteen ruminally fistulated steers (482 kg, four steers per treatment) were blocked by weight and assigned to the same four supplements in a 30-d digestion trial. Supplementation increased (P < .01) digestible DMI and forage DMI (P < or = .04) and tended (P = .09) to increase digestible NDF intake but did not alter (P > or = .15) apparent DM or NDF digestibility.(ABSTRACT TRUNCATED AT 250 WORDS)

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)

Dietary fibers differ in their effects on large bowel epithelial proliferation and fecal fermentation-dependent events in rats

The effects of different fiber types and processing on putative protective mechanisms for colorectal cancer were evaluated. Rats were fed diets of similar nutrient balance containing either no added fiber or 10% fiber from various sources. The rate of distal colonic epithelial proliferation, measured by the metaphase arrest method, was dependent on fiber type; ranking of fibers from highest to lowest yielded the following order: methylcellulose > coarse wheat bran > fine wheat bran approximately parboiled and extruded rice brans > no fiber (P = 0.012). Effect on stool output ranked identically. Ranking of effect on fecal pH, from most to least acidic was as follows: coarse wheat bran approximately the rice brans > fine wheat bran > no fiber approximately methylcellulose (P = 0.00001). Coarse wheat bran gave significantly higher fecal butyrate concentrations than did the rice brans, which in turn gave higher levels than fine wheat bran, methylcellulose and the no-fiber diet. Proximal colon epithelial proliferation was unaffected by diet although cecal short-chain fatty acid concentrations and pH were affected. Different fibers have different effects on events in the fecal environment and distal colonic epithelium. Putative protective events (increased output, low fecal pH, high butyrate, low proliferation) are not equally affected and are unlikely in themselves to allow prediction of the protective effect of a fiber.

Kinetics of hydration and functional specific gravity of fibrous feed by-products

Five studies were conducted to evaluate the kinetics of digestion, hydration, and functional specific gravity (FSG) of various feed by-products (FBP) in vitro. The water-holding capacity (WHC) of alfalfa and orchardgrass (1.428 and 1.005 g/g of insoluble DM [IDM], respectively) was higher (P < .05) than the WHC of FBP, which ranged from .175 for distillers grains to .481 g/g of IDM for brewers grains pellets. Rate of hydration was the highest in brewers grains pellets and beet pulp (.215 and .252 min-1, respectively), whereas the lowest hydration rates were observed in orchardgrass, corn cob pellets, and soyhulls (.055 to .066 min-1). Loss of associated gasses from feed particles fermented in vitro increased (P < .05) their FSG when the contents of incubation tubes were transferred to pycnometers, compared with that when the incubation was carried out directly in the pycnometers (1.17 vs 1.13) to determine their FSG. Gas produced during fermentation delayed the increase in the FSG of all sources of brewers grains and beet pulp, corn gluten feed, distillers grains, orchardgrass, alfalfa, and wheat middlings but not of corn cob pellets, cottonseed hulls, and soyhulls. Averaged across hours of incubation, the FSG of FBP (except beet pulp) was either higher (P < .05) or tended to be higher than that of alfalfa and orchardgrass. Particle size of FBP did not influence FSG during fermentation in vitro. The WHC and FSG of feeds may be helpful in predicting the rate of passage of feeds through the rumen.

Interaction of feed intake level on comparative ruminal and total tract digestion of dry-rolled and steam-flaked corn

Four Holstein steers (208 kg) with "T" cannulas in the rumen and proximal duodenum were used in a 4 x 4 Latin square design experiment to evaluate the interaction of feed intake level on comparative ruminal and total tract digestion of dry-rolled and steam-flaked corn. The basal diet contained (DM basis) 6% alfalfa hay, 6% sudangrass hay, 75% corn, 2% yellow grease, 5% cottonseed meal, 3% cane molasses, and 3% supplement. The corn portion of the diet was provided as either dry-rolled (density = .54 kg/L) or steam-flaked (density = .36 kg/L). Dry matter intake was restricted to allow for .64 vs 1.28 kg/d of weight gain (1.6 vs 2.4% of BW). Ruminal digestibility of OM, starch, and feed N were not affected (P > .10) by DMI. Postruminal digestion of OM and N and total tract digestibility of OM and DE decreased (P < .05) as DMI was increased. Total tract starch digestibility was not influenced (P > .10) by DMI. Steam flaking corn increased (P < .05) ruminal digestibility of OM and starch and postruminal and total tract digestibility of OM, starch, N, DE, and ME. Increasing DMI and steam flaking decreased (P < .05) ruminal pH and molar proportion of acetate. It is concluded that corn processing is the primary factor influencing site and extent of starch digestion. Decreasing DMI increases DE value of the diet; however, ME value is not affected because of increased energy loss as methane.

Effect of ruminally undegradable protein from fish meal on growth and reproduction of peripuberal Brahman bulls

Thirty-nine Brahman bulls (301.7 +/- 4.1 d; 202.7 +/- 4.7 kg) were allotted to one of two treatments and fed soybean meal (SBM)- or fish meal (FIS)-based supplements and hay to examine the effects of source of protein on growth and reproductive development. The fish meal supplement had 72% ruminally undegradable protein (RUP) and the soybean meal supplement had 47% RUP. Bulls assigned to the FIS treatment had higher (P < .01) total weight gain (81.2 +/- 1.4 vs 71.2 +/- 2.2 kg), higher (P < .01) ADG (.97 +/- .02 vs .85 +/- .03 kg), and better (P < .05) feed:gain ratio (7.6 +/- .1 vs 8.6 +/- .1 feed/BW gain for FIS vs SBM, respectively). Age at first motile spermatozoa was not affected (P > .05) by source of protein (429.9 +/- 9.6 vs 427.2 +/- 9.5 d, for bulls receiving FIS or SBM supplements, respectively). Likewise, age at puberty (473.3 +/- 21.7 d vs 465.9 +/- 12.9 d for bulls receiving FIS and SBM supplements, respectively) was similar for both treatment groups. There were no differences between treatments in scrotal circumference at those stages. At puberty semen quality was similar for bulls receiving FIS or SBM treatments, and no differences existed in LH and testosterone concentrations between treatments. We conclude that fish meal supplement increased growth but did not alter reproductive parameters in Brahman bulls.

True digestibility of amino acids and protein in pigs with 13C as a label to determine endogenous amino acid excretion

The objective of this study was to determine whether differential labeling of 13C occurs in pigs fed diets with different 13C abundances and, if so, to use 13C as a label to determine true amino acid digestibility. Forty-eight pigs averaging 10.5 kg BW were fed dietary treatments consisting of a corn-corn gluten meal-crystalline amino acid diet (C-CGM) and a wheat-soybean meal diet (W-SBM). The 13C abundance of the amino acid fraction (AAF) of the C-CGM and W-SBM diets averaged delta 13C -14.19 and -26.36/1000, respectively. Three pigs/treatment group were killed when groups averaged 10.5 (initial), 22.9, and 46.6 kg BW, and AAF of organs were analyzed for 13C abundance. Carbon 13 in empty body AAF increased (-18.14, -13.98, and -12.66/1000) with increasing body weight in pigs fed the C-CGM diet and decreased (-18.06, -22.78, and -24.76/1000) in pigs fed the W-SBM diet. Liver, small intestine, and longissimus muscle tissues showed similar trends. Each tissue had dietary treatment effects (P < .001) and dietary treatment x weight group (P < .001) interactions. Ten pigs averaging 55.0 kg BW from each treatment group were assigned to metabolism cages and fed at 0700 and 1900. Six of these pigs from each treatment group were implanted with T-cannulas in the ileum and given a 17-d recovery period. At 1900 on d 0 of the collection phase, pigs were switched to the opposite diet that contained chromic oxide.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary level and source of neutral detergent fiber and ileal endogenous nitrogen flow in pigs

Two experiments were conducted to study the effect of dietary level and source of neutral detergent fiber (NDF) on ileal dry matter flow and on total and endogenous N flow at the terminal ileum. Twenty-two crossbred 6-wk-old castrated male pigs with an average BW of 9 kg were used. The pigs were fitted with a post-valvular T-cecal cannula and two indwelling blood catheters. During the experimental period of 10 d, the pigs were 11 wk of age with an average BW of 14 kg. They were fed 2.6 times their maintenance requirement for energy of a corn starch-based, semisynthetic diet. The diets contained 178 g of soy isolate/kg as the only source of nitrogen (N). In diets of Exp. 1, purified NDF was included at 0 and 200 g/kg of feed at the expense of glucose. The diets of Exp. 2 contained one of the three different NDF sources (purified NDF, wheat bran, or sunflower hulls) at a level of 144 g of NDF/kg of DM. The purified NDF (pNDF) was isolated from the same batch as the wheat bran (WB) used in Exp. 2. The endogenous N flow at the terminal ileum of these pigs was determined with the 15N-isotope dilution method. The inclusion of NDF in the experimental diets increased (P < .05) the daily DM flow at the terminal ileum. Dry matter flow was increased .697 g for every g/kg increase in NDF in the diet. The different sources of dietary NDF gave similar (P > .05) ileal DM flows.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of excess dietary leucine and leucine catabolites on growth and immune responses in weanling pigs

Two experiments with weanling pigs were conducted to study the effects on growth and immune responses of excess dietary L-leucine (LEU) and dietary supplementation with the LEU catabolites, alpha-ketoisocaproic acid (KIC) and beta-hydroxymethyl butyrate (HMB). In Exp. 1, 80 pigs were randomly allocated according to initial BW and ancestry to five replications of four dietary treatments (four pigs/pen). The control diet contained wheat, oat groats, menhaden fish meal, and dried whey and provided 1.12% LEU. Treatment diets were the control plus 1.12% LEU, 1.12% KIC, or .4% HMB. The experiment lasted 6 wk. In Exp. 2, 36 pigs were randomly allocated to nine replications of four dietary treatments in a 2 x 2 factorial arrangement. Treatments consisted of two concentrations of dietary LEU and a daily i.m. injection of dexamethasone (DEX) or saline. Pigs were fed a control corn-soybean meal and dried whey diet (1.56% LEU) or the control diet plus 1.56% of crystalline LEU. Pigs were individually penned and the experiment lasted 4 wk. Growth performance, plasma free amino acids, plasma urea nitrogen, and humoral and cellular immune responses were measured. Results indicated that LEU concentrations in practical diets and supplementation with KIC and HMB (Exp. 1) did not detrimentally affect growth and immune response. The high LEU concentration and DEX injection used in Exp. 2, however, were detrimental to both growth and immune response.

Influence of high-starch vs high-fiber energy supplements on performance of stocker cattle grazing wheat pasture and subsequent feedlot performance

A 3-yr study was conducted to determine effects of high-starch (HS) or high-fiber (HF) energy supplements on performance of fall-weaned steer calves (n = 192, Exp. 1 and 2; n = 84, Exp. 3) grazing winter wheat pasture (Triticum aestivum variety 2157) and subsequent feedlot performance. The steers received 1) no supplement (CL) other than free-choice access to a commercial mineral mixture or 2) were hand-fed 6 d/wk either a corn-based HS supplement, or 3) a soybean hull/wheat middling-based HF supplement. In Exp. 1 (1989-1990), a fourth treatment provided ad libitum access to the HF supplement (SFHF). Supplements contained 88 mg of monensin/kg and the combination of ionophore, minerals and salt (8%) was used to limit intake of the SFHF supplement. Target level of daily consumption of all supplements was .75% of mean BW. Stocking density was increased by 33% (i.e., from 1.24 to 1.65 steers/ha) in Exp. 1 and 3, and by 22 to 44% in Exp. 2 when supplements were fed. Subsequent to grazing wheat pasture in Exp. 2 and 3, feedlot performance and carcass quality (Exp. 2 only) of the cattle were measured. Over the 3-yr period (pooled analysis), mean daily supplement consumption was .65% BW. Daily gains were increased (P < .001) .15 kg by supplementation and were .92, 1.06, and 1.08 kg for CL, HS, and HF, respectively. Daily gains were not influenced (P > .45) by type of energy supplement. Mean supplement conversions (kilograms asfed.kilogram of increased gain-1.hectare-1) were 5.4 for HS and 5.0 for HF and did not differ (P > .95). Subsequent feedlot daily gain was decreased .09 kg (P < .05) by supplementation in Exp. 2 but not in Exp. 3 (P > .80). This supplementation program for growing cattle on wheat pasture allowed stocking density to be increased by approximately one-third and increased daily gains by .15 kg.

Acceptability of wheat-sorghum composite flour products: an assessment

The acceptability of sorghum as human food has been a problem in Tanzania even in regions showing promising potential for its production and utilization. Reasons given for low acceptability of sorghum products as human foods include unpleasant colour, aroma, mouthfeel, taste, unpleasant aftertaste and stomachfeel. An acceptability test of selected sorghum products was, therefore, conducted in the Department of Food Science and Technology, Sokoine University of Agriculture, Morogoro, Tanzania. The objective of the test was to determine consumers' preference for the following wheat-sorghum composite flour products: bread and buns or 'maandazi'. The products were prepared using sorghum flour composited with wheat flour in the following proportions: 100% brown sorghum flour (standard products); and 80:20%; 60:40%; 40:60% and 20:80% for wheat/sorghum (white and brown) composite flours. Results indicated that in the case of composite flour bread, preference for the product improved as the amount of sorghum flour decreased. In the case of buns or 'maandazi' the 100% sorghum flour products of both white and brown were equally preferred. Buns prepared from 100% sorghum flour of white and brown varieties showed promising potential in the improvement of the acceptability of sorghum products. Taking advantage of such products, especially in villages, could enhance sorghum utilization in rural communities.