Biomedical subjects

G C Fahey

Publications and source records attributed to G C Fahey.

At least 127 records · Page 7Linked to original sources

PubMed1987

Effects of heat and alcohol treatments of soybean meal on nitrogen utilization by sheep.

Soybean meal (SBM) was treated with aqueous solutions of ethanol or propanol at room temperature or at 80 C to study treatment effects on SBM-N solubility and utilization by sheep. Soybean meal was soaked in an excess of 70% (v/v) ethanol at 80 C (ET-80), 70% ethanol at 23 C (ET-23) or 70% propanol at 80 C (PR-80). Nontreated SBM and nontreated SBM heated at 80 C without alcohol treatment (NT-80) served as controls. Nitrogen solubility in McDougall's buffer was lowest (P less than .05) for PR-80 and ET-80 (2.2 and 4.7% of total N, respectively), intermediate (P less than .05) for ET-23 (9.0%), greater (P less than .05) for nontreated SBM (36.2%) and highest for NT-80 (40.2%). In an situ study using three ruminally cannulated cows and two bags per treatment per animal per removal time, more (P less than .05) N remained in in situ bags after 3, 6, 9 and 12 h incubation for ET-23, ET-80 and PR-80 than for nontreated SBM and NT-80. A lamb metabolism trial, using 15 lambs in each of two periods, compared nontreated SBM, ET-23, ET-80, PR-80 and urea as N supplements. Nitrogen retention was higher (P less than .02) for lambs fed SBM treatments compared with urea. When the same N supplements were fed to wethers in a 5 X 5 Latin square experiment and duodenal N flow was measured, non-ammonia non-bacterial N flow was higher (P less than .07) for wethers fed SBM treatments than for wethers fed urea.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Propanol↗

PubMed1987

Evaluation of corn fiber, cottonseed hulls, oat hulls and soybean hulls as roughage sources for ruminants.

An in situ trial (randomized complete block design) using cows, and a site and extent of digestion trial (Latin square design) using sheep were conducted to study the potential of corn fiber (CF), cottonseed hulls (CSH), oat hulls (OH) and soybean hulls (SH) as roughage sources for ruminants. Two feedlot trials with steers and one with lambs (completely randomized design with factorial arrangements of treatments) were conducted to study the potential of CF and SH as energy supplements relative to corn. In situ rate of ruminal dry matter (DM) disappearance (3 to 36 h) and extent of DM disappearance (36 h) indicated that CF and SH were more fermentable in the rumen compared with OH or CSH, with SH being the most fermentable. Total tract digestibilities of DM, organic matter (OM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were above 70% for sheep fed CF and SH diets, and were 50% or less for sheep fed OH and CSH diets. A ranking of by-products in terms of nutritive value followed the trend: CF greater than SH greater than OH greater than CSH. Lamb feedlot trial data showed that CF was of similar nutritive value to corn and of higher nutritive value than SH at the 50% level of supplementation. Corn-fed lambs responded better than CF- or SH-fed lambs at the 70% level of supplementation. Data from steer feedlot trials showed that CF was of similar quality to corn and of higher quality than SH. Dramatic differences exist in by-product feed utilization by ruminants. All by-products tested appeared to have some usefulness as dietary components.

Animal Feed↗

PubMed1987

Effects of dietary energy level and supplemental protein source on performance of growing steers and nutrient digestibility and nitrogen balance in lambs.

Four experiments were conducted to evaluate three crude protein (CP) sources (urea, U; soybean meal, SBM; corn gluten meal, CGM) in diets based on corn silage (high energy) or grass hay (low energy). In Exp. 1 and 2, growing steers were fed all combinations of energy and protein source at 10.5 or 12% CP. Steers fed high energy diets or 12% CP had improved (P less than .05) daily gains and feed:gain over 84 d. Protein source had no effect (P greater than .05) on performance except that steers fed U consumed more (P less than .05) feed than those fed CGM. Steers were fed experimental diets to a common weight and switched to an 85% concentrate diet for finishing. During finishing, steers fed low energy diets in the growing period consumed more (P less than .05) feed and had increased (P less than .05) feed:gain compared with those fed high energy diets. Growing lambs were fed the same diets as steers. At 10.5% CP, lambs fed high energy diets had higher (P less than .05) digestibilities of dry matter (DM), organic matter (OM), nitrogen (N) and fiber components, and retained more (P less than .05) N. For lambs on 12% CP, high energy diets had higher (P less than .05) DM and OM digestibilities and lower (P less than .05) N digestibilities. At 12% CP, energy level had no effect (P greater than .05) on N retained. Protein source had no effect (P greater than .05) on N retention. There appeared to be no advantage in supplementing with ruminally undegradable proteins, i.e. CGM, in these experiments.

Animals↗

PubMed1987

Effects of ethanol and heat treatments of soybean meal and infusion of sodium chloride into the rumen on ruminal degradation and escape of soluble and total soybean meal protein in steers.

Soybean meal (SBM) treated with 70% ethanol at 80 C (ET), nontreated SBM (NT) or a ureacasein-corn mix (UC) was fed to steers fitted with ruminal and duodenal cannulae to study ruminal N metabolism. Sodium chloride (NaCl) was ruminally infused at 0 or 500 g/d. Nitrogen supplements provided approximately 70% of total dietary N. Experimental design was a 6 X 6 Latin square with a 3 X 2 factorial arrangement of treatments. Total duodenal N flows and non-ammonia, non-bacterial-N (NANB-N) flows were higher (P less than .05) when steers were fed SBM treatments compared with UC, and higher (P less than .05) when steers were fed ET compared with NT. Percentage of SBM-N escaping ruminal degradation was greater (P less than .05) when steers were fed ET compared with NT, and greater (P less than .05) when NaCl was infused into the rumen. Duodenal flows of total, indispensible and dispensible amino acids were increased (P less than .05) when steers were fed SBM treatments compared with UC, and greater (P less than .05) when steers were fed ET compared with NT. No differences in soluble N flows at the omasum were observed due to treatment. Bacterial protein comprised the majority of the N leaving the rumen. Both ruminal NaCl infusion and ethanol and heat treatment of SBM increased ruminal SBM-N escape.

Animals↗

PubMed1987

Effects of feeding or infusing ammonium salts of volatile fatty acids on ruminal fermentation, plasma characteristics, and milk production of cows.

Eight rumen-fistulated Holstein cows, averaging 77 d postpartum, were used in a replicated 4 X 4 Latin square design with 28-d periods to investigate the effect of ammonium salts of isobutyrate, 2-methylbutyrate, isovalerate, and n-valerate on animal performance and their possible mechanism(s) and site(s) of action. Each cow was fed ad libitum a complete mixed diet of 55% corn silage and 45% concentrate on a dry basis that was supplemented with 1.8 kg of premix daily. Treatments were 1) control, 2) ammonium salts of volatile fatty acids in premix, 3) ammonium salts of volatile fatty acids ruminally infused, or 4) ammonium salts of volatile fatty acids abomasally infused. Mean ruminal fluid pH and concentrations of ammonia and volatile fatty acids for treatment comparisons were not different. Plasma concentrations of isobutyrate, 2-methylbutyrate, and valerate differed among treatments, but there was no significant effect on dry matter intake, milk production, milk composition, or efficiency of feed utilization. Apparent nutrient digestibility; disappearance of dry matter, cellulose, and nitrogen from polyester bags suspended in the rumen; and plasma concentrations of glucose, free fatty acids, and growth hormone also were not significantly affected by treatment.

Abomasum↗

PubMed1987

Effects of ethanol, heat, and lipid treatment of soybean meal on nitrogen utilization by ruminants.

Ruminant nitrogen utilization of soybean meal treated with 1) 70% ethanol at 23 or 78 degrees C, 2) 10% coconut oil or tallow, or 3) a combination of 70% ethanol at 78 degrees C and coconut oil or tallow was evaluated. Nitrogen solubility was lowest for soybean meal treated with ethanol at 78 degrees C, ethanol plus coconut oil and ethanol plus tallow. In situ nitrogen disappearance was lowest for soybean meal treated with ethanol at 78 degrees C, ethanol plus coconut oil, and ethanol plus tallow. Rates of nitrogen disappearance between 3 and 12 h were lowest for soybean meal treated with ethanol at 78 degrees C, ethanol plus coconut oil, and ethanol plus tallow. Nitrogen retained by lambs was greater for lambs fed soybean meal treated with ethanol at 78 degrees C than for those fed untreated soybean meal. Ruminal ammonia 4 h postfeeding was lowest for lambs fed soybean meal treated with ethanol at 78 degrees C, ethanol plus coconut oil, and coconut oil. These data indicate that the 78 degrees C ethanol treatment improved nitrogen utilization.

Animal Feed↗

PubMed1987

Effects of treating wheat straw with pH-regulated solutions of alkaline hydrogen peroxide on nutrient digestion by sheep.

An experiment using a 4 X 4 Latin square design was to determine effects of treating wheat straw with pH-regulated (pH = 11.5) solutions of hydrogen peroxide on site and extent of nutrient digestion in multiple-fistulated sheep. Regulating reaction pH at 11.5 prevented solubilization of some cell wall hemicelluloses, resulting in improved retention of DM. Diets fed to sheep contained 33 or 70% wheat straw either untreated or treated with alkaline hydrogen peroxide. Sheep fed diets of treated wheat straw digested more DM, NDF, ADF, and cellulose anterior to the duodenum and in the total tract than when fed diets of untreated wheat straw. Apparent CP digestion before the duodenum was highest when sheep were fed the treated 33% wheat straw diet and untreated 70% wheat straw diet. Treatments did not affect apparent nutrient digestibilities in the large intestine. Ruminal pH was lower when sheep were fed the alkaline hydrogen peroxide-treated or diets containing 33% wheat straw. Ruminal ammonia concentrations were highest when sheep were fed the untreated 70% wheat straw diet. Molar proportions of ruminal acetic and propionic acids were unaffected by diet. Alkaline hydrogen peroxide treatment substantially increased susceptibility of structural carbohydrates of wheat straw to microbial degradation in the gastrointestinal tract of sheep.

Animal Feed↗

PubMed1987

Ruminal nitrogen metabolism in steers as affected by feed intake and dietary urea concentration.

Four multiple-cannulated steers (340 kg) were used in a 4 X 4 Latin square design with a 2 X 2 factorial arrangement of treatments. Steers were fed a diet of 50% ground hay and 50% concentrate at two intakes (1.4 and 2.1% of BW), with urea and 15N-enriched ammonium sulfate infused continuously into the rumen at .4 or 1.2% of diet DM. Ratios of purines and diaminopimelic acid-N to N in fluid-associated and particulate-associated bacteria and in protozoa were similar among treatments but were lower for protozoa than for bacteria. Diaminopimelic acid-N:N was higher for fluid-associated vs. particulate-associated bacteria. Enrichment of 15N was similar between bacteria among treatments and was 30% lower for protozoa. Turnover rates of 15N in bacteria, NH3N, and non-NH3N pools were faster for steers infused with 1.2 than those infused with .4% urea, indicating less efficient usage of ammonia with higher urea. A method is described to estimate the proportion of duodenal nitrogen comprising bacterial and protozoal nitrogen.

Animal Feed↗

PubMed1987

Effects of feed intake and dietary urea concentration on ruminal dilution rate and efficiency of bacterial growth in steers.

Four multiple-fistulated steers (340 kg) were fed a diet containing 50% ground grass hay, 20% dry distillers grains, and 30% concentrate at two intakes (7.2 or 4.8 kg DM/d). Urea (.4 or 1.2% of the diet) was infused continuously into the steers' rumens. The experimental design was a 4 X 4 Latin square with a 2 X 2 factorial arrangement of treatments. Infusing urea at .4 or 1.2% of the diet resulted in ruminal NH3 N concentrations of 4.97 and 9.10 mg/dl, respectively. Feeding steers at high rather than low intake decreased ruminal and total tract digestibilities of organic matter, NDF, and ADF but did not increase ruminal escape of N. However, apparent N escape from the rumen calculated using purines, but not 15N, as a bacterial marker was higher when 1.2 vs. .4% urea was infused. Feeding at high rather than at low intake increased the total pool of viable bacteria per gram organic matter fermented in the rumen. Although ruminal fluid outflows and particulate dilution rates were greater when steers were fed at high than at low intakes, efficiencies of bacterial protein synthesis were unaffected by intake. The possibility of increased N recycling within the rumen with feeding at the higher intake is discussed.

Animal Feed↗

PubMed1986

Effects of pure and auto-oxidized forms of cholesterol on plasma, liver lipids and hepatic lipogenesis in chicks.

Pure cholesterol (PC), oxidized cholesterol (OC) and cholestane-3 beta,5 alpha,6 beta-triol (CT) were fed to male Hubbard chicks for 3 weeks in a basal grain diet. Feed consumption and weight gain of chicks fed OC (1.0%) or CT (0.1%) were not significantly different from that of chicks fed PC (0.85%) or the basal diet alone. Plasma cholesterol level was significantly (P less than 0.05) higher in chicks fed PC compared to controls; however, compared to other dietary groups, differences were not significant. Measurement of hepatic lipogenesis, in vivo, from labeled substrates showed that [14C]acetate was primarily utilized for fatty acid synthesis in all dietary groups. The relative order was PC greater than PC + CT greater than OC greater than CT greater than basal. Conversely, [3H]mevalonate was preferentially used for cholesterogenesis and the relative effectiveness was basal greater than CT greater than OC greater than PC + CT greater than PC.

Animals↗

PubMed1986

Effects of purified dietary fiber sources on beta-carotene utilization by the chick.

Effects of various purified dietary fiber components on beta-carotene utilization by the chick were investigated in two experiments (expt.). Eight-day-old Columbian X New Hampshire male (expt. 1) or female (expt. 2) chicks were fed a vitamin A-deficient diet for 1 wk and then fed beta-carotene-supplemented diets containing 0% fiber, 7% arenaceous flour or 7% of a purified fiber source for 4 wk. Results of expt. 1 showed that hemicellulose, lignin and citrus pectin, but not arenaceous flour or polygalacturonic acid, depressed beta-carotene utilization by the chick, as measured by percentage of consumed beta-carotene stored in liver as vitamin A relative to the 0% fiber control. In expt. 2, effects of the methoxyl content of pectin were studied. High and medium methoxyl apple pectin, citrus pectin and polygalacturonic acid reduced storage of vitamin A in liver. Low methoxyl apple pectin had no significant effect on beta-carotene utilization. Thus, several purified forms of dietary fiber significantly reduced beta-carotene utilization by chicks when fed at the 7% supplementary level. Moreover, with pectin, there was an inverse relationship between methoxyl content of pectin and beta-carotene utilization.

Animals↗

PubMed1986

Effects of forage particle size, level of feed intake and supplemental protein degradability on microbial protein synthesis and site of nutrient digestion in steers.

A 2(3) factorial arrangement of treatments was used to study main effects and interactions between particle size of prairie hay (chopped vs ground), two levels of feed intake (60 and 90% of ad libitum) and ruminal degradability of protein sources [dry corn gluten feed (DCGF) vs dry distillers grains (DDG)] on ruminal and total tract digestion in eight ruminal- and duodenal-cannulated steers. Steers were fed every 2 h to approach steady-state feeding conditions. Steers fed ground hay diets digested higher (P less than .05) percentages of total digestible organic matter (OM) and neutral detergent fiber (NDF) in the rumen and had lower (P less than .05) nonammonia-nonbacterial N (NANBN) flows to the duodenum than did those fed chopped hay, probably because greater surface area of ground hay allowed more extensive ruminal fermentation. Protein source X intake interactions were noted for ruminal OM and NDF digestion when expressed as percentages of total digestion. At low intakes, steers fed DCGF had higher (P less than .05) percentages of total digestible OM and NDF disappearing in the rumen than did those fed DDG. Steers fed DCGF had lower total N, NANBN and total amino acid (AA) flows at the duodenum than did those fed DDG, indicating that less DCGF protein escaped ruminal degradation. Steers fed DDG had greater (P less than .05) total tract NDF digestion, suggesting that escape protein from DDG may stimulate hindgut fermentation and thereby affect site and extent of nutrient digestion. Regression analysis indicated that extent of ruminal fermentation and efficiency of microbial growth in vivo are associated with ruminal rates of passage within individual animals. When steers were fed at high-intake levels (1.6% of body weight), ruminal dilution rates were not increased (P less than .05) due to forage particle size or level of intake treatments, accounting, in part, for the lack of expected treatment differences in efficiency of bacterial growth and duodenal N flow, and for the low number of interactions between main effects.

Animal Feed↗

PubMed1986

Effects of dietary alfalfa-orchardgrass hay and lasalocid on sow reproductive performance.

Forty-eight second, third and fourth parity crossbred sows were randomly allotted to four dietary treatments: corn:alfalfa-orchardgrass hay (46%; CH); CH plus lasalocid (CHL); corn-soybean meal (CS) or CS plus lasalocid (CSL). Sows were fed these diets through two successive gestations with dietary treatment initiated at 35 d post-coitum and continued until parturition. To equalize daily metabolizable energy intake (6.6 Mcal/sow), 2.64 kg of CH and CHL diets and 1.86 kg of CS and CSL diets were fed. Lasalocid intake was 130 mg X sow-1 X d-1. Sows were weighed and backfat measurements were taken at 35 and 109 d of gestation. Sows also were weighed 14 d postpartum. A 14% crude protein corn-soybean meal diet was fed ad libitum to all sows during lactation and feed intake was recorded. Colostrum samples were obtained within 4 h of farrowing. All live piglets were weighed at birth and 14 d of age. There were no significant differences among dietary treatments in number of live piglets born, piglet birth weight, piglet weight at 14 d of age or sow rebreeding efficiency. Sows fed CHL and CSL diets had more (P less than .12) live piglets at 14 d postpartum and lower (P less than .03) total fat in colostrum than did CH- and CS-fed sows. Alfalfa-orchardgrass hay feeding resulted in less (P less than .04) backfat deposition during gestation, more (P less than .04) weight loss from 109 d postcoitum to 14 d postpartum and increased (P less than .002) feed consumption during lactation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1986

Effects of alkaline hydrogen peroxide treatment of wheat straw on site and extent of digestion in sheep.

Two experiments (4 X 4 Latin squares) were conducted, using four multiple-cannulated wethers (mean body weight, 65 kg), to determine effects of treating wheat straw (WS) with alkaline solutions (pH 11.5) of hydrogen peroxide (AHP; .26 g hydrogen peroxide/g WS) on site and extent of nutrient digestion in sheep. Diets contained either 33 to 37% (low WS) or 70 to 72% (high WS) AHP-treated (T) or non-treated (C) WS. Treatment of WS with AHP resulted in increased acid detergent fiber and cellulose concentrations and decreased acid detergent lignin (ADL) concentrations compared with non-treated WS. In Exp. 1, intakes were held constant at approximately 1,044 g dry matter (DM)/d. When fed AHP-treated WS diets, wethers digested more (P less than .05) DM, neutral detergent fiber (NDF) and cellulose in the stomach (54.8, 47.4, 51.6 and 20.0%; 65.6, 68.8, 51.5 and 37.2%; 66.6, 74.2, 45.2 and 40.7% of intake, respectively, for low WS-T, high WS-T, low WS-C and high WS-C diets) and in the total tract (83.0, 74.8, 68.4 and 50.0%; 81.8, 81.0, 53.9 and 42.1%; 85.2, 86.9, 50.2 and 47.6%, respectively, for the low WS-T, high WS-T, low WS-C and high WS-C diets), and had lower (P less than .05) ruminal pH than when fed the non-treated WS diets. In Exp. 2, the same wethers were fed diets similar to those fed in Exp. 1, but at ad libitum intake. Wethers consumed less (P less than .05) feed when fed the high WS-C diet than when fed the other three diets (2,234, 2,526, 2,271 and 1,297 g/d for the low WS-T, high WS-T, low WS-C and high WS-C diets, respectively). Digestibilities of DM, NDF and cellulose were higher (P less than .05) when sheep were fed the treated WS diets than when fed the non-treated WS diets (82.7, 70.7, 68.4 and 58.0%; 78.6, 72.9, 49.4 and 51.6%; 78.0, 84.0, 53.8 and 37.5%, respectively, for the low WS-T, high WS-T, low WS-C and high WS-C diets). Fluid and particulate dilution rates in the rumen were higher (P less than .08) when wethers consumed AHP-treated WS diets compared with non-treated WS diets (8.21, 8.56, 6.96 and 6.81%/h; 6.06, 6.73, 4.05 and 3.15%/h, respectively, for the low WS-T, high WS-T, low WS-C and high WS-C diets). The AHP treatment was successful in overcoming the major barriers to microbial degradation of WS in the gastrointestinal tract of wethers.

Animal Feed↗

PubMed1986

Comparison of the effects of three methods of harvesting and storing alfalfa on nutrient digestibility by lambs and feedlot performance of steers.

Two lamb digestion and three steer growth experiments were conducted to study the feeding value of alfalfa harvested as direct-cut silage (DCS) with grain added prior to ensiling or as low-moisture silage (LMS) or hay with grain added at feeding. In all experiments, alfalfa-grain mixtures contained approximately 50% alfalfa and 50% concentrate (dry matter [DM] basis). In Exp. 1, lambs fed DCS alone consumed less DM than lambs fed LMS or hay alone or any of the alfalfa-grain mixtures. Apparent digestibilities of DM and fiber components were higher (P less than .05) for DCS than for LMS or hay. Lambs that were fed LMS digested more (P less than .05) DM and fiber components than lambs fed hay. Addition of grain resulted in increased (P less than .05) DM digestibility and decreased (P less than .05) digestibilities of neutral detergent fiber and acid detergent fiber. In Exp. 2, growing steers (271 kg) fed DCS-grain had increased (P less than .05) weight gains compared with steers fed hay-grain. Steers fed any of the alfalfa-grain mixtures gained weight more rapidly (P less than .05) than steers fed corn silage (CS)-based diets. In a third experiment, finishing steers (283 kg) fed DCS-grain, LMS-grain, hay-grain or CS-based diets performed similarly (P greater than .05), although steers fed DCS-grain had higher (P less than .05) dressing percentages and yield grades than steers that were fed the other three diets and were fatter (P less than .05) than those fed LMS-grain or CS. In Exp. 4, lambs fed DCS-grain or LMS-grain had higher (P less than .05) apparent DM and organic matter digestibilities than lambs fed CS-based diets with similar forage:grain proportions. In Exp. 5, finishing steers (326 kg) fed DCS-grain gained similarly (P greater than .05) to steers fed LMS-grain or an 85% concentrate diet based on high-moisture corn. Steers fed CS diets had lower (P less than .05) gains and increased (P less than .05) feed per gain compared with steers fed DCS-grain, LMS-grain or high-moisture corn.

Animal Feed↗

PubMed1986

Effects of feed intake and protein degradability on ruminal characteristics and site of digestion in steers.

Four multiple-fistulated Hereford steers were used in a 4 X 4 Latin square design with a 2 X 2 factorial arrangement of treatments [two intakes (9.1 and 6.1 kg dry matter/d) and two protein sources differing in ruminal degradability (dry distillers grains and dry corn gluten feed)]. Steers fed at the high intake had faster fluid dilution rates (7.63 versus 6.52%/h), higher ruminal fluid outflows (120.2 versus 91.7 L/d), lower apparent ruminal digestibilities of organic matter (41.3 versus 44.3%) and neutral detergent fiber (56.0 versus 60.2%), and lower total tract digestibilities of neutral detergent fiber (64.3 versus 68.7%) than when they were fed at the low intake. Steers fed dry corn gluten feed had higher apparent ruminal digestibilities of organic matter (45.5 versus 40.1%) and neutral detergent fiber (60.2 versus 56.0%) and lower duodenal flows of nonammonia-nonbacterial N (40.1 versus 52.2% of N intake) than when they were fed dry distillers grains. Efficiency of ruminal bacterial growth was higher when steers were fed at the high versus low intakes. Efficiency of ruminal bacterial growth and site and extent of fiber digestion, especially hemicellulose, but not ruminal escape of protein, can be readily altered by manipulation of feed intake of moderately high forage diets.

Ammonia↗

PubMed1985

Plasma lipid and lipoprotein cholesterol levels in swine. Modification of protein-induced response by added cholesterol and soy fiber.

Piglets, aged 8 weeks and weighing 12-18 kg, were fed semi-purified casein or soy protein diets, with or without cholesterol and soy hull fiber, for 2 months. In addition to observing the effects of the dietary treatments on growth, the modification of the primary hypocholesterolemic action of soy protein by cholesterol and soy fiber was studied. Pigs fed the soy protein or casein diets grew normally with no difference in weight gain. Plasma triglyceride and phospholipid levels, as well as several plasma metabolic indices examined, were not significantly affected by dietary treatment. However, plasma total cholesterol was higher (but not significantly) in pigs fed casein than in those fed soy protein alone. Cholesterol feeding induced markedly significant (P less than 0.05) hypercholesterolemia with either protein source, compared to feeding the proteins without added cholesterol. Dietary soy fiber fed simultaneously with cholesterol decreased the cholesterol-induced hypercholesterolemia, but the reduction was significantly greater (P less than 0.05) with soy protein than with casein in the diet. Analyses of the lipoprotein cholesterol indicated that LDL cholesterol was much more sensitive to the changes induced by feeding cholesterol and soy fiber than either HDL or VLDL cholesterol. These findings suggest a beneficial role of dietary soy fiber in hypercholesterolemia.

Animals↗

PubMed1985

Influence of dietary alfalfa:orchardgrass hay and lasalocid on in vitro estimates of dry matter digestibility and volatile fatty acid concentrations of cecal contents and rate of digesta passage in sows.

Four mature crossbred sows were fistulated in the cecum, with two sows fed a corn-alfalfa:orchardgrass hay (46%) diet (CH) and two fed a corn-soybean meal diet (CS). Four experiments were conducted to evaluate buffers, incubation times, buffer pH and substrate and inocula sources in an in vitro, anaerobic, mixed-culture system. In vitro dry matter digestibility (IVDMD) and substrate solubility in buffer (SS) were determined. In Exp. 1, substrates were CH and CS diets with cecal inocula obtained from CH- and CS-fed sows. The bicarbonate (B) buffer resulted in lower (P less than .01) and less variable SS for all treatments. In vitro dry matter digestibility was higher (P less than .01) for the CS diet at both 24 and 48 h incubation. Use of the B buffer also resulted in higher (P less than .001) IVDMD values. In Exp. 2, substrates were either as in Exp. 1 or were freeze-dried cecal contents (CC) from CH- or CS-fed sows. In vitro dry matter digestibility of CC was lower (P less than .006) than IVDMD of diet, while IVDMD was higher (P less than .02) with cecal inocula than fecal inocula. In Exp. 3, substrate-inocula treatments were CH-CH, CH-CS, CS-CH and CS-CS. Substrate solubility was lower (P less than .05) at pH 5.8 than at pH 6.8. In vitro dry matter digestibility was higher when substrate and inocula were from the same source and at pH 5.8. In Exp. 4, CC and inocula were from sows fed CH and CS diets with or without lasalocid. In vitro dry matter digestibility was higher with CC from lasalocid-fed sows and inocula from sows fed no lasalocid. The CH diet resulted in higher acetate (Ac) and lower propionate (Pr) molar proportions than did the CS diet, while lasalocid increased molar proportion Pr and decreased molar proportion Ac in cecal contents from sows fed either diet. Corn-alfalfa:orchardgrass hay-fed sows had a faster rate of digesta passage and shorter cecal retention time than did CS-fed sows.

Animals↗