RATE OF PROTEIN DEGRADATION AND NUTRIENT DIGESTION OF VARIOUS NITROGEN SOURCES IN CONTINUOUS CULTURE OF RUMEN CONTENTS

1987 ◽  
Vol 67 (3) ◽  
pp. 745-756 ◽  
Author(s):  
J. E. GARRETT ◽  
R. D. GOODRICH ◽  
M. D. STERN ◽  
J. C. MEISKE

A dual flow continuous culture fermentor system was used to estimate ruminal rate of protein degradation and influence of supplemental nitrogen (N) source on digestion of total dietary crude protein (CP), dry matter (DM) and organic matter (OM). Four experimental diets contained predominantly corn and were isocaloric (14.7 M J DE kg−1) and isonitrogenous (12% CP on a DM basis) with urea, soybean meal (SBM), linseed meal (LSM) or corn gluten meal (CGM) as sole supplemental N sources. Fermentor flow rates were adjusted daily to attain liquid and solid dilution rates of 10 and 5% h−1, respectively. Total dietary N digestibility was greater (P < 0.05) in fermentors receiving urea than in those receiving CGM, while fermentors receiving SBM or LSM were intermediate (72.9, 54.9, 64.0 and 63.2%, respectively). Bacterial CP flow was higher (P < 0.05) from fermentors receiving urea or SBM than from those receiving CGM, with fermentors receiving LSM intermediate (1.31, 1.29, 1.02 and 1.14 g d−1, respectively). True OM digestibility was greater (P < 0.05) for diets supplemented with urea or LSM than for those supplemented with CGM (65.1, 60.4 and 51.2%, respectively). The rate of protein degradation was greater (P < 0.05) for LSM-CP than CGM-CP with SBM-CP intermediate (15.73, 6.88 and 10.13% h−1, respectively). Calculated bypass of potentially digestible protein for SBM-CP, LSM-CP and CGM-CP was 15.9, 10.9 and 29.1%, respectively. Total amino acid flow (g d−1) was higher (P < 0.05) for fermentors receiving SBM than for those receiving LSM. Total bacterial amino acid flow (g d−1) was higher (P < 0.05) for fermentors receiving SBM than for fermentors receiving CGM. Differences among diets for dietary amino acid flow (g d−1) were not significant. Key words: Ruminal protein degradation, soybean meal, linseed meal, corn gluten meal, continuous culture system

1997 ◽  
Vol 77 (2) ◽  
pp. 241-251 ◽  
Author(s):  
P. H. Robinson

Four multiparous Holstein dairy cows in mid-lactation were utilized in a 4 × 4 Latin square design experiment to measure the response in intestinal amino acid profiles to progressive substitution of blood meal for corn gluten meal as the protein supplement. In addition, the influence of these protein sources on rumen fermentation and digestion as well as forestomach bacterial growth and escape were compared with a diet supplemented with soybean meal, a rapidly rumen-degraded protein source. Cows were offered a mixed silage ration of alfalfa silage (79.8% of DM) and corn silage (20.2% of DM) twice daily. Cows were also offered mixed concentrate at 123% (DM:DM) of the mixed silage ration in six equal meals per day to provide soybean meal, corn gluten meal, blood meal or a combination of the latter two sources as the primary supplemental protein source. Rumen soluble non-ammonia N concentrations were higher in cows fed soybean meal and declined linearly as blood meal substituted for corn gluten meal in the concentrate. Forestomach disappearance of N tended (P = 0.09) to be higher for the cows fed soybean meal vs. all other diets, and tended (P = 0.09) to be higher with the combined corn gluten meal and blood meal diet vs. the diets containing either alone. The latter is consistent with higher forestomach digestion of DM and OM in cows fed the combined diet. Rumen pool sizes of most DM components were lower when cows were fed soybean meal and, with the exception of N pools, increased linearly as blood meal substituted for corn gluten meal. Duodenal flow of amino acid protein was lower when cows were fed soybean meal, due mainly to reduced bacterial flow, and was lowest for the combined diet within the corn gluten meal and blood meal diets. The amino acid profile of duodenal protein differed for 12 of 17 amino acids examined when cows were fed the soybean meal diet vs. the other diets, and 12 of 17 amino acids either increased or decreased linearly as blood meal substituted for corn gluten meal. Data reported here and by previous researchers suggest an associative effect of addition of corn gluten meal and blood meal to the diet which increased rumen degradation of dietary protein. These data also show that manipulating the dietary source of supplemental protein can influence the amino acid profile of duodenally delivered amino acid protein as well as indicate that the rate of rumen degradation of individual amino acids differs among protein sources. In this study, methionine, cystine and histidine appeared to be more rapidly degraded in corn gluten meal than in blood meal, whereas glutamic acid, proline, isoleucine, threonine and lysine were more rapidly degraded in blood meal. Key words: Dairy cow, rumen bacteria, amino acid


2011 ◽  
Vol 40 (5) ◽  
pp. 939-946 ◽  
Author(s):  
Felipe Barbosa Ribeiro ◽  
Eduardo Arruda Teixeira Lanna ◽  
Marcos Antonio Delmondes Bomfim ◽  
Juarez Lopes Donzele ◽  
Moisés Quadros ◽  
...  

It was determined in this work the coefficients of apparent and true digestibility of protein and amino acids of five feeds (corn, wheat bran, soybean meal, corn gluten meal, fish meal) in Nile tilapia. It was used 252 reverted Thai strain Nile tilapia (Oreochromis niloticus) in growth phase, with weight of 310 ± 9.68 g, distributed in experimental randomized blocks design, with five treatments, six replicates per treatment and seven fish per experimental unit. Each experimental diet contained a single source of protein, composed by the studied ingredients. An additional group of fish was fed protein-free diet for quantification of the endogenous fraction and determination of true digestibility coefficients. Digestibility was estimated by the indirect method by using chromium oxide at the concentration of 0.50% of the diet as a marker, performing fecal collection at every four hour interval by using decantation technique. Coefficients of apparent digestibility of the protein and amino acids are: corn, 83.57 and 82.45%; wheat bran 82.87 and 81.47%; soybean meal 91.12 and 89.41%; corn gluten meal 90.07 and 87.78%; fish meal 83.53 and 81.65% respectively. Coefficients of true digestibility of protein and the mean of the amino acids are: corn, 90.02 and 89.60%; wheat bran 89.62 and 89.14%; soybean meal 93.58 and 91.88%; corn gluten meal 92.50 and 90.34%; fish meal 86.01 and 84.27%, respectively.


2008 ◽  
Vol 26 (No. 1) ◽  
pp. 38-47 ◽  
Author(s):  
Ma Ying ◽  
Lin Li ◽  
Sun Da-Wen

A method to obtain an oligopeptide with high Fischer ratio is described. Corn gluten meal (CGM) was hydrolysed with Alcalase 2.4L using a two-step hydrolysis. In the first-step hydrolysis, the enzyme reaction conditions for hydrolysing CGM were optimised by using the orthogonal experimental design, while pH = 8.0, temperature = 55°C, enzyme to substrate ratio (3:97, w/w), and the substrate concentration = 5% were identified as the optimum conditions, under which up to 11.62% degree of hydrolysis (DH) could be obtained. The hydrolysate was then fractionated by ultrafiltration using a membrane with the molecular cutoff of over 10 kD at 20 kPa. For the second-step hydrolysis, the filtrate was adjusted to pH 6.0, then papain was added at 50°C and the mixture was maintained for 3 hours. The hydrolysate was obtained after inactivating papain and centrifuging. Then the salt (mainly NaCl) in the hydrolysate was removed with an ion exchange resin at the speed of 8 times bed volume per hour, and aromatic amino acids were removed through absorption by active carbon. By using Sephadex G-25 gel filtration chromatography, a peptide mixture with low molecular weights between 1000 and 1300 was obtained. Finally, tests on amino acid composition and free amino acid concentration of oligopeptide solution showed that the oligopeptide had a high Fischer ratio of 34.71 and the yield of 11.59%.


1983 ◽  
Vol 56 (1) ◽  
pp. 194-205 ◽  
Author(s):  
M. D. Stern ◽  
L. M. Rode ◽  
R. W. Prange ◽  
R. H. Stauffacher ◽  
L. D. Satter

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