Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “DIGESTION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,801 records · Page 100Linked to original sources

Effects of forage particle size and grain fermentability in midlactation cows. I. Milk production and diet digestibility.

Our study investigated the effects of, and interactions between, level of dietary ruminally fermentable carbohydrate (RFC) and forage particle size on milk production, nutrient digestibility, and microbial protein yield for dairy cows fed one level of dietary NDF. Eight cows (61 days in milk) were assigned to four treatments in a double 4 x 4 Latin square. Treatments were arranged in a 2 x 2 factorial design; finely chopped alfalfa silage (FS) and coarse alfalfa silage (CS) were combined with concentrates based on either dry cracked shelled corn (DC; low RFC) or ground high-moisture corn (HMC; high RFC). Diets were fed ad libitum as a total mixed rations with a concentrate to forage ratio of 61:39. Diets based on DC had a predicted NEL content of 1.73 Mcallkg dry matter (DM), while HMC diets contained 1.80 Mcal/kg DM. Diets averaged 18.7% CP, 24.0% NDF, 18.3% ADF, and 27.4% starch on a DM basis. Mean particle size of the four diets was 6.3, 2.8, 6.0, and 3.0 mm for DCCS, DCFS, HMCCS, and HMCFS, respectively. Increasing level of RFC decreased dry matter intake (DMI) from 25.0 to 23.8 kg/ d and organic matter intake from 22.3 to 21.1 kg/d, but intake was not affected by particle size. Milk production averaged 44.0 and 26.8 kg/d solids corrected milk (SCM) and was not affected by diet, but increasing level of RFC tended to increase milk yield. Efficiency of milk production, expressed as SCM/DMI, increased from 1.06 to 1.14 when level of RFC was increased. Milk composition or yield of milk components was not affected by diet, and averaged 3.53% fat, 3.11% protein, 1.55 kg/d fat, and 1.36 kg/d protein. Total tract digestibility of DM and OM increased from 71.4 to 73.0% and 72.4 to 76.1% for DM and OM, respectively, when level of RFC was increased. Total tract digestibility of fiber was unaffected by diet, but total tract starch digestibility increased from 93.1 to 97.4% when HMC replaced DC. Total urinary excretion of the purine derivatives uric acid and allantoin increased from 415 to 472 mmol/d when level of RFC was increased, and calculated microbial N supply increased from 315 to 365 g/d. When expressed as per kilogram of digestible OMI, increasing level of RFC tended to increase microbial N supply (20.4 vs. 22.2 g/kg). Cow productivity was not affected by forage particle size and ruminally fermentable carbohydrates in this study.

Allantoin↗

Effects of corn silage hybrid and dietary concentration of forage NDF on digestibility and performance by dairy cows.

Eight intact multiparous cows and four ruminally and duodenally cannulated primiparous cows were fed four diets in a replicated 4 x 4 Latin square design: 1) 17% forage neutral detergent fiber (NDF) with brown midrib corn silage (BMRCS), 2) 21% forage NDF with BMRCS, 3) 17% forage NDF with conventional corn silage (CCS), and 4) 21% forage NDF with CCS. Diets contained 17.4% crude protein and 38.5% NDF. Each period consisted of 4 wk for intact cows and 2 wk for cannulated cows. For intact cows, DM intake was higher for BMRCS than CCS, and milk urea N was higher for 21 than 17% forage NDF. Milk protein yield tended to be higher and milk urea N lower for cows fed BMRCS than those fed CCS. Milk yield and milk protein percentage were similar among treatments. For the cannulated cows, ruminal mat consistency was similar among treatments. Based on a 72 h in situ incubation, BMRCS was lower in indigestible NDF than CCS. The BMRCS resulted in a higher proportion of ruminal propionate than CCS. Cows fed 21% forage NDF had a higher proportion of acetate and a lower proportion of propionate than cows fed 17% forage NDF. The total tract digestibility of nutrients and efficiency of bacterial N synthesis were similar among treatments, except that BMRCS resulted in lower intestinal fatty acid digestibility than CCS, and 17% forage NDF tended to result in higher total tract fatty acid digestibility than 21% forage NDF. Ruminal NDF digestibility was similar among dietary treatments. The increased milk production observed from feeding BMRCS in some studies may be explained by higher DM intake rather than increased total tract digestibility of the diets.

Animals↗

Digestible energy values of diets with different fat supplements when fed to lactating dairy cows.

A total collection digestion trial using high producing lactating cows (average milk yield = 40.7 kg/d) was conducted to measure the effect of different fat supplements on dietary digestible energy (DE) concentrations and to calculate the DE value of the supplements. A diet with no supplemental fat, 2 diets with 1.75 or 3.5% (dry basis) Ca salts of palm fatty acids (Ca-PFA), and 2 diets with 1.6 or 3.2% hydrogenated triacylglycerides from palm oil (HPO) were fed in a 5 x 5 Latin square experiment with 28-d periods. Concentrations of supplemental long-chain fatty acids in the diets were 1.7 and 3.4% for the 2 supplementation rates. Dry matter intake was reduced when cows were fed the high concentration of Ca-PFA, but cows fed Ca-PFA produced more milk than cows fed the control diet or diets with HPO. The type or amount of fat supplementation did not affect measures of rumen fermentation or in situ fiber digestibility. Digestibility of energy, dry matter, and organic matter were higher for diets with Ca-PFA than for diets with HPO, mainly because of increased fatty acid digestibility. The dietary concentration of DE was similar between the control diet and diets with HPO (2.97 Mcal/kg), but it increased as the concentration of Ca-PFA increased (3.04 and 3.16 Mcal/kg for low and high supplementation rates). The calculated DE concentrations of the supplements averaged 7.3 and 3.1 Mcal/kg for Ca-PFA and HPO. The 2001 National Research Council dairy model accurately estimated DE concentrations in all diets (<1% difference).

Animal Nutritional Physiological Phenomena↗

Effects of monensin on ruminal forage degradability and total tract diet digestibility in lactating dairy cows during grain-induced subacute ruminal acidosis.

The effects of monensin premix supplementation on ruminal pH characteristics and forage degradability, and total tract diet digestibility during grain-induced subacute ruminal acidosis (SARA) in lactating dairy cows receiving a total mixed ration were investigated. Six multiparous, rumen-fistulated Holstein cows were used in a 2-treatment, 2-period (5 wk per period) crossover design. During wk 5 (d 29 to 35) of each period, SARA was induced using a grain challenge model, and ruminal pH was measured continuously using indwelling pH probes. Ruminal degradation of corn silage and alfalfa haylage was determined using the in situ (nylon bag) technique, and total tract diet digestibility was determined by total fecal collection during wk 5. Monensin supplementation did not affect dry matter intake, milk yield, and composition, and ruminal pH characteristics under these experimentally induced SARA conditions. Rates of ruminal forage fiber degradability were similar between control and monensin-treated cows; however, monensin supplementation increased total tract fiber digestion. This study indicates that monensin altered total tract nutrient digestion by increasing fiber digestion at postruminal sites.

Acidosis↗

A comparison of processed conventional corn silage to unprocessed and processed brown midrib corn silage on intake, digestion, and milk production by dairy cows.

We studied the effects of mechanical processing and type of hybrid on the nutritive value of corn silage for lactating cows. Treatments were brown midrib (BMR) corn silage that was unprocessed (U-BMR), BMR corn silage that was processed (P-BMR), and a conventional corn silage that was processed (P-7511). All silages were harvested at a theoretical chop length of 19 mm. The chemical compositions of the silages were similar among treatments except that BMR silages were lower in lignin and higher in protein than P-7511. Brown midrib silages had greater 30-h in situ and in vitro NDF digestion than did P-7511, and processing had no effect on 30-h in situ and in vitro fiber digestion, but it increased in situ starch digestion after 3 and 12 h of incubation. Both processed silages had a smaller proportion of particles >1.91 cm and fewer whole corn kernels compared with unprocessed silage. Lactating cows were fed a total mixed ration (TMR) consisting of 42% of each silage type, 40% concentrate, 10% alfalfa silage, and 8% alfalfa hay (DM basis). Cows fed TMR containing P-BMR ate more DM and produced more milk than cows fed P-7511. At feeding, the TMR containing U-BMR had a larger proportion of particles >1.91 cm when compared with the TMR of cows fed processed silages, and after 24 h the difference was even greater, indicating that cows fed unprocessed corn silage sorted more. Cows fed TMR with P-7511 and P-BMR had greater total tract digestibility of organic matter, crude protein, and starch compared with cows fed U-BMR. In vivo digestibility of neutral detergent fiber was greatest for cows fed P-BMR when compared with the other treatments.

Animals↗

Effects of addition of essential oils and monensin premix on digestion, ruminal fermentation, milk production, and milk composition in dairy cows.

Four ruminally cannulated, lactating Holstein cows were used in a 4 x 4 Latin square design (28-d periods) with a 2 x 2 factorial arrangement of treatments to study the effects of dietary addition of essential oils (0 vs. 2 g/d; EO) and monensin (0 vs. 350 mg/d; MO) on digestion, ruminal fermentation characteristics, milk production, and milk composition. Intake of dry matter averaged 22.7 kg/d and was not significantly affected by dietary additives. Apparent digestibilities of dry matter, organic matter, neutral detergent fiber, and starch were similar among treatments. Apparent digestibility of acid detergent fiber was increased when diets were supplemented with EO (48.9 vs. 46.0%). Apparent digestibility of crude protein was higher for cows fed MO compared with those fed no MO (65.0 vs. 63.6%). Nitrogen retention was not changed by additive treatments and averaged 27.1 g/d across treatments. Ruminal pH was increased with the addition of EO (6.50 vs. 6.39). Ruminal ammonia nitrogen (NH3-N) concentration was lower with MO-supplemented diets compared with diets without MO (12.7 vs. 14.3 mg/100 mL). No effect of EO and MO was observed on total volatile fatty acid concentrations and molar proportions of individual volatile fatty acids. Protozoa counts were not affected by EO and MO addition. Production of milk and 4% fat-corrected milk was similar among treatments (33.6 and 33.4 kg/d, respectively). Milk fat content was lower for cows fed MO than for cows fed diets without MO (3.8 vs. 4.1%). The reduced milk fat concentration in cows fed MO was associated with a higher level of trans-10 18:1, a potent inhibitor of milk fat synthesis. Milk urea nitrogen concentration was increased by MO supplementation, but this effect was not apparent when MO was fed in combination with EO (interaction EO x MO). Results from this study suggest that feeding EO (2 g/d) and MO (350 mg/d) to lactating dairy cows had limited effects on digestion, ruminal fermentation characteristics, milk production, and milk composition.

Animals↗

Influence of type and amount of grain on digestibility of rations containing cottonseed hulls.

Twelve rations formulated from barley, corn, soy bean mill feed, or wheat and cottonseed hulls were fed to three sheep per ration to measure the influence of type and amount of grain on digestibility of the proximate constituents and cellulose. Each ration was fed at 2% body weight and with grain 20, 40, and 60% of dry matter. Net energy values for maintenance, gain, and milk production were calculated from the digestion coefficients. Dry matter digestibility for rations containing barley, corn, soybean mill feed, and wheat averaged over the three percents of grain were 63.1, 62.5, 60.0, and 61.5%, and 58.9, 61.6, and 64.0% for low, medium, and high grain. Digestibility of dry matter for soy bean-mill-feed rations was less than rations containing the other grains. Digestibility of crude fiber was lowest for wheat, followed by corn, barley, and soy bean mill feed in ascending order. Calculated net energy values usually increased lineraly with increasing grain for each type of grain with the exception of wheat. Wheat was least acceptable for ruminants.

Animal Feed↗

Varying protein content and nitrogen solubility for pluriparous, lactating Holstein cows: digestive performance during early lactation.

Thirty-four pluriparous Holstein cows were used to examine effects of crude protein (15.3 vs. 13.6%, dry matter basis) and nitrogen solubility (39.7 vs. 47.9%) on digestibility, energy and protein balances, and related traits during early lactation. Cows were assigned randomly at parturition to treatments in a 2 X 2 factorial arrangement; measurements were during wk 6, 10, and 14 postpartum. Diets were protein supplements (varying in protein content and nitrogen solubility), low-protein concentrate, corn silage treated with urea at ensiling, and wilted grass silage fed individually for ad libitum intake. Reducing nitrogen solubility of diet improved energy intake and productive energy factors but resulted in no significant increase of milk yield or body tissue balances, although body fat balance tended to be higher for low-solubility diets. There was no effect on overall partition of nitrogen in the body. Digestibility of carbohydrates and protein was higher for 15.3 than for 13.6% crude protein diets, resulting in higher total digestible nutrients and digestible and metabolizable energy of dry matter. Raising crude protein in the ration decreased milk yield of cows in early lactation but generally increased body tissue balances. Concentrations of rumen ammonia and blood urea nitrogen were not influenced by nitrogen solubility; increasing dietary protein increased concentrations of both, although not enough to increase consumption of free water. Best digestive efficiency was for animals fed the ration of medium crude protein and low nitrogen solubility.

Ammonia↗

Effects of sarsaponin on digestion and passage rates in cattle fed medium to low concentrate.

Four dairy cows with duodenal cannulae were fed diets consisting of sorghum silage (67% of dietary dry matter) at 85% of ad libitum intake with 0 (control diet) or 44 ppm (dry matter) sarsaponin (sarsaponin diet) in a crossover experiment. Digestion coefficients for organic matter were low but increased by addition of sarsaponin both in the rumen (43.7 versus 32.4%) and total tract (52.1 versus 48.2%). Digestibilities of starch and nitrogen in the rumen and total tract and passage rates of fluid, concentrate, and silage tended to be greater for the sarsaponin diet. Extent of ruminal digestion of organic matter was related to passage rate of concentrate (correlation .81) and fluid (correlation .75). In a second study, diets contained 50% concentrate either with or without sarsaponin added at 44 ppm. Ruminal pH for animals given sarsaponin tended to be lower 4, 8, and 12 h after feeding. In situ rate constants of dry matter disappearance tended to be greater with the control diet for corn, alfalfa, and prairie hay and lower for milo and soybean meal. Lag time of digestion tended to be longer with the sarsaponin diet for corn, milo, soybean meal, and corn gluten meal but shorter for alfalfa and prairie hay. Although sarsaponin may increase ruminal digestion of medium to low concentrate diets, in situ data indicate that effects may differ with type of feed.

Animal Feed↗

Influence of pecan shells and hulls as a roughage source on milk production, rumen fermentation, and digestion in ruminants.

In Experiment 1, 20 lambs (36 kg) were fed five diets containing 0, 5, or 10% pecan shells or hulls to evaluate digestion and nitrogen balance. Digestion was not depressed by diets containing 5% shells. Protein digestibility was not reduced and nitrogen balance was higher for lambs fed 5% hulls than for lambs in other groups. In Experiment 2, 8 Holstein cows (29.3 kg milk/d) were assigned to two diets: basal and basal with 5% shells in the grain mix. Cows fed diets containing shells produced the same amount of milk and milk fat as control cows. In Experiment 3, 12 Holstein cows (27.3 kg milk/d) were assigned to the same two diets used in Experiment 2 and a third treatment received 5% pecan hulls in the grain mix. Cows fed shells or hull diets reduced concentrate intake and milk production. In Experiment 4, 12 Hereford X Angus steers (474.5 kg) were fed diets used in Experiment 3 to examine rumen fermentation, digestion, and passage rates. Steers fed hulls had lower rumen ammonia N and higher rumen pH compared with steers fed the basal diet. Total rumen volatile fatty acid concentration was not different among treatments. Generally, rumen fluid from steers fed hulls had higher proportions of acetate and lower proportions of butyrate. Rumen fluid and particulate passage rates and digestion measurements were not affected by addition of shells or hulls.

Animal Feed↗

Chemical factors involved in ruminal fiber digestion.

In the United States, cattle are commonly fed diets containing cereal grains. The presence of starch and sugars reduces fiber digestion, which may in turn depress intake. In this paper, chemical constraints that may be responsible for the decrease in fiber digestion are explored. A major factor appears to be rumen pH. Moderate depression in pH, to approximately 6.0, results in a small decrease in fiber digestion, but numbers of fibrolytic organisms are usually not affected. Further decreases to 5.5 or 5.0 result in depressed growth rates and decreased fibrolytic microbes, and fiber digestion may be completely inhibited. Proliferation of organisms on readily fermentable carbohydrates may increase the need for total nitrogen as both ammonia and amino acids. The value of amino acids to cellulolytic organisms appears to be primarily as sources of isobutyric, isovaleric, and 2-methylbutyric acids. This reinforces the need to establish dietary requirements for nonprotein nitrogen, degradable protein, and isoacids. Other factors affecting fiber digestion, such as inhibition of cellulytic enzymes and plant concentrations of lignins and phenyl propanoids, are also discussed.

Animals↗

Rumen turnover and digestion of normal and brown midrib sorghum x sudangrass hybrid silages in dairy cattle.

Eight growing Holstein heifers and four ruminally cannulated adult Holstein steers fed ad libitum were used in 4 X 4 Latin square designs. Diets included two sorghum X sudangrass varieties, Redlan X Greenleaf and Redlan X Piper, and their corresponding brown midrib mutants. Acid detergent fiber and acid detergent lignin concentrations tended to be lower for brown midrib mutants than for normal genotypes of the same variety. Digestion kinetics for in situ studies showed no difference in rate constants between normal and brown midrib sorghums, but extent of digestion at 72 h was significantly higher for brown midrib mutants than for normal genotypes, suggesting that lignin has no effect on digestion rate but does result in a decreased extent of digestion. In growing dairy heifers, brown midrib sorghum X sudangrass had higher digestibilities for organic matter, neutral detergent fiber, acid detergent fiber, cellulose, and hemicellulose fractions than did the normal genotype for Redlan X Greenleaf.

Animal Feed↗

In vivo digestibility of corn and sunflower intercropped as a silage crop.

Six nonlactating Holstein cows in a 3 x 3 Latin square total collection digestion trial were used to evaluate three low DM (less than 26%) silage types: 1) corn; 2) corn and sunflower intercropped and 3) sunflower. Feeding periods consisted of a 7-d adjustment followed by a 5-d collection period. Dry matter intake was similar for the three treatments; 12.5, 12.1, and 12.0 kg, respectively. Percent apparent digestibilities for DM, NDF, and N for corn and corn-sunflower were similar and greater than for sunflower: DM (69.6, 68.2, 57.4); NDF (68.1, 61.5, 51.6); and N (66.3, 66.5, 63.6). No differences were observed for digestibilities of ADF, hemicellulose, starch, or for N retention. Percent ether extract digestibility was greatest for corn-sunflower and sunflower silage when compared with digestibility of corn silage (82.5, 77.9, vs. 66.3). Major changes in rumen fermentation patterns were not observed as evidenced by rumen molar proportions of propionate, isobutyrate, isovalerate, valerate, or acetate to propionate ratios. No difference was observed for rumen NH3 N (2.7, 3.2, 4.1 mg/dl, respectively). Corn and sunflower intercropped silage had intermediate concentrations of fat, fiber, and protein when compared with those of corn or sunflower silages.

Animal Feed↗

Recovery of fecal chromium used as a digestibility marker in cattle.

Chromium content of fecal samples that were mixed with Cr-mordanted rumen contents at 5 or 10 g/200 g feces in Experiment 1 and at 5 or 10 g/300 and 200 g feces in Experiment 2 was determined by atomic absorption spectroscopy. Recovery of Cr was estimated after digesting fecal samples, which were frozen fresh and later thawed or dried in either a forced draft oven at 60 degrees C or in a microwave oven in Experiment 1. Experiment 2 evaluated the efficacy of each of three methods of digestion in recovery of Cr from fecal samples. Recoveries of Cr from feces were calculated relative to the Cr content of the Cr-mordanted rumen contents, which were determined by atomic absorption spectroscopy of samples digested with concentrated nitric acid in the presence or absence of the wetting agent Tween 80. Recovery of Cr from fecal samples frozen fresh and later thawed was greater than that from either forced draft oven or from microwave oven-dried samples, especially when the concentrated nitric acid digestion was used. Neither the double ashing procedure nor the digestion with the weaker nitric acid did not improve Cr recoveries from the samples.

Animals↗

Duodenal rapeseed oil infusion in early and midlactation cows. 1. Intestinal apparent digestibility of fatty acids and lipids.

Rapeseed oil was infused continuously into the duodenum of lactating dairy cows. Five separate trials were conducted with differences in amount of oil infused (1.0 to 1.5 kg/d), in lactation stage (early to late), and in basal diet (corn or grass silages). The effects of lecithin addition (9 g/d) also were studied. Oil infusion did not affect the apparent digestibility of defatted organic matter. Fatty acid, ether extract, and total lipid digestibilities in control cows were 62 to 82%, 72 to 76%, and 59 to 73%, respectively. Intestinal apparent digestibilities of oil fatty acid and ether extract fractions were estimated to be 63 to 74% and 67 to 81%, respectively. Intestinal apparent digestibility of oil total lipids was only 20 to 57% due to a significant increase in nonfatty acid lipid excretion (160 to 750 g/d above control cows), which sharply decreased the energy value of the infused oil. Lecithin did not modify apparent digestibility in oil-infused cows.

Animals↗

Effect of canola fat on ruminal and total tract digestion, plasma hormones, and metabolites in lactating dairy cows.

The effects of canola fat on digestion and metabolism were investigated by incorporating 0, 4.5, 9, 13.2, or 17.4% Jet-Sploded canola seed into a diet containing a 60:40 (DM) concentrate:forage ratio. The diets contained 16.5% CP, 30% alfalfa silage, and 10% whole-crop oat silage on a DM basis and were fed for ad libitum consumption as TMR to 10 ruminally cannulated Holstein cows in early lactation. Jet-Sploded canola seed supplementation did not change ruminal pH or NH3 N concentrations, but VFA concentrations declined with increasing level of inclusion. Apparent digestibilities of DM, OM, CP, NDF, and ADF were unaffected by level of inclusion of Jet-Sploded canola seed, but ether extract digestibility declined linearly, which resulted in similar ether extract absorption across the three diets supplemented with canola fat. Based on in sacco data, the percentages of ruminal digestion of OM and CP declined with increasing inclusion of Jet-Sploded canola seed. Plasma glucose and FFA concentrations tended to respond in a quadratic fashion, plasma insulin concentration declined linearly, and plasma glucagon and somatotropin concentrations were unaffected by dietary treatment. The results indicate that a positive productive response may be expected from dietary inclusion of about 5% Jet-Sploded canola seed, but the benefits of increased energy density associated with higher inclusion levels may be offset by reduced availability of energy in the rumen and decreased fat digestibility postruminally. The substantial effects of time postfeeding on ruminal fermentation and on concentrations of plasma hormone and metabolites in animals fed TMR demonstrate that infrequent sampling can result in misleading results and, thus, invalid interpretation of the influence of dietary fat on these parameters.

Ammonia↗

Development of buffer systems for pH control and evaluation of pH effects on fiber digestion in vitro.

An in vitro buffering system capable of pH control between pH 5.8 and 6.8 was developed to examine the effect of media pH on disappearance of NDF at various times of fermentation and to assess initially the effect of media pH on kinetics of NDF digestion. The pH conditions selected for evaluation of these buffer systems were 5.8, 6.2, and 6.8. Use of McIlvaine's solution with sodium bicarbonate was not successful because of rapid drifting of pH downward during fermentation. To evaluate the effectiveness of citric or phosphoric acids as components of phosphate-bicarbonate buffer systems, alfalfa silage and a mixture of alfalfa silage and corn grain (1:1 mixture, dry basis) were fermented for 0, 12, 24, 48, and 72 h. The pH of each flask was measured at 0, 4, 12, 24, 48, and 72 h postinoculation, and pH was readjusted with bicarbonate solution when necessary. Drifting of media pH downward was more noticeable when phosphoric acid was used to adjust the buffer pH than with citric acid. Citric acid had no adverse effects on NDF digestion compared with phosphoric acid when used to adjust a phosphate-bicarbonate buffer system. Alfalfa hay, bromegrass hay, and corn silage were incubated for 0, 12, 24, 48, 72, or 96 h at pH 5.8 or 6.8 using the phosphate-bicarbonate buffer system adjusted with citric acid. Estimation of kinetics of NDF digestion indicated that a decrease in media pH from 6.8 to 5.8 resulted in a marked reduction in NDF digestion; the largest apparent difference was extended digestion lag time.

Animal Feed↗

Effects of raw pea flour on nutrient digestibility and immune responses in the preruminant calf.

Two milk substitute diets for which the protein was provided either exclusively by skim milk powder (control) or partially (34%) by dehulled raw pea flour were given for 2 and 4 wk, respectively, to five preruminant calves, each fitted with a reentrant ileocecal cannula. Ileal apparent digestibility was lower with the pea diet during wk 1 than with the control diet. Four of the cannulated calves exhibited significant intolerance to the pea diet, resulting in lower digestibility during wk 4. In contrast, fecal digestibility of the pea diet, measured in four additional calves without reentrant cannulas, did not significantly decrease between wk 1 and 4. The AA composition of ileal digesta from the first group of calves did not vary greatly, suggesting that the differences observed in their apparent digestibility of proteins were due mainly to changes in the loss of endogenous proteins. However, pea legumin survived digestion in the small intestine in amounts generally equivalent to 1 to 3% of intake. Most of that undigested fraction was smaller than the native legumin: 40 to 200 kDa instead of 360 kDa. Also, a 45-kDa fragment was detected in the urine. Increased intestinal permeability could have favored the development of the high systemic anti-pea antibody titers that were observed in all of the calves.

Amino Acids↗

Refine your search to explore more results.