scholarly journals Estimation of Relationship Between In Situ and In Vitro Rumen Protein Degradability of Extruded Full Fat Soybean

Author(s):  
Arzu Erol Tunç ◽  
Yusuf Cufadar ◽  
Sema Yaman

The objectives of this study were to estimate the protein degradability of extruded full fat soybean (ESB) by in situ (nylon bag) and in vitro enzymatic method and to develop an equation in order predict in situ degradability from in vitro values. In the study enzymatic technique; hydrolysis after 1 h (INV1) and after 24 h (INV24) by a purified protease extracted from Streptomyces griseus in a borate-phosphate buffer at pH 8 was used as in vitro method. Relationship between in situ effective protein degradability (INSE) and in vitro degradability after 1 and 24 hours incubations (INV1 and INV24) were determined. In situ protein degradability was measured at 0, 2, 4, 8, 16, 24, and 48 and at 72 h incubations in the rumen of 3 Holstein cows. In the study INSE, INV1 and INV24 were determined as 58.05, 20.24 and 41.46% respectively. Despite there were differences between in situ and in vitro protein degradability values, correlation coefficients between in situ and in vitro protein degradability of ESB were high and regression equations for estimation of in situ from in vitro were found significant. As conclusion in vitro enzymatic protein degradability (INV1 and INV24) can be used for estimation of in situ effective protein degradability of extruded full fat soybean.

1997 ◽  
Vol 45 (2) ◽  
pp. 291-306 ◽  
Author(s):  
J.L. De Boever ◽  
B.G. Cottyn ◽  
J.M. Vanacker ◽  
C.V. Boucque

The percentage of feed protein escaping rumen degradation was measured by the in situ method (%EPsitu) for 29 compound feeds, untreated and formaldehyde-treated soyabean meal and 12 forages: 3 grass silages, 2 maize silages, fresh grass, grass hay, fodder beets, fresh potatoes, ensiled beet pulp, chopped ear-maize silage and brewers' grains. Loss of particles through bag pores was determined by the difference between the washable fraction (W) and the fraction soluble in borate-phosphate buffer at pH 6.7 (S). W - S was most pronounced for compound feeds (on average 14.4 percentage units), for brewers' grains and maize silages. A correction of %EPsitu, assuming that W - S degrades like the potentially degradable fraction, was not appropriate. Solubility in borate-phosphate buffer after 1 h, enzymic degradability by protease from Streptomyces griseus or ficin after 1, 6 and 24 h and near infrared reflectance spectroscopy (NIRS) (for compound feeds alone) were examined as a routine method to predict %EPsitu. With the buffer and S. griseus the effect of pH (6.7 vs. 8.0) and at pH 8.0 the effect of amount of substrate (500-mg sample vs. 20 mg N) were tested. With ficin, 500-mg samples were incubated at pH 6.7. Predictions were better when compound feeds and forages were considered separately. However, the best in vitro method was different for the 2 feed categories, being solubility in buffer for the compound feeds and enzymic degradation of a constant amount of protein with S. griseus at pH 8.0 for forages. NIRS showed potential to predict %EPsitu of compound feeds, but needs more reference samples. The Dutch feed tables appeared more accurate than the best in vitro method for compound feeds, but was too inaccurate for some forages like fodder beets, maize silage and ear-maize silage.


2005 ◽  
Vol 56 (8) ◽  
pp. 797 ◽  
Author(s):  
M. Aslam Mirza ◽  
E. L. Miller

Various feed proteins were incubated independently with bacterial protease from Streptomyces griseus (SGP), papain (Corica papaya), and ficin (Ficus glabrata) in a simple laboratory assay to predict ruminal protein degradability. The estimates obtained from in vitro assays were compared with those obtained from an in situ analysis using synthetic fibre bags. The rate and extent of degradation in vitro using proteases from non-rumen sources differed among substrates used. A high correlation coefficient (r2 = 0.99) was observed between N-degradability from the in vitro method using SGP and in situ estimates when soybean meal was the substrate. Soybean meal nitrogen (N) was almost completely hydrolysed (0.99) in vitro. The correlation coefficients were low and variable with assays using other enzymes. The correlation coefficient was also high (r2 = 0.77–0.84) with in vitro methods using either SGP, papain, or ficin when incubated with fish meal. The N disappearance from barley in vitro was slow to moderate. The ‘b’ estimate of barley obtained with the in vitro assay was significantly (P < 0.01) lower than that observed in situ. Slower proteolysis observed in barley may possibly be linked to poor accessibility of structural proteins rather than the degradability of N per se. None of the enzymes could rank barley in the same order as the in situ method.


1989 ◽  
Vol 38 (4) ◽  
pp. 269-283 ◽  
Author(s):  
P. Susmel ◽  
B. Stefanon ◽  
C. R. Mills ◽  
M. Colitti

1999 ◽  
Vol 1999 ◽  
pp. 156-156
Author(s):  
G. Gizzi ◽  
E.R. Deaville ◽  
D.I. Givens

The assessment of protein degradability in the rumen is a complex process. The infinite combination of interaction between the rumen microbial population and the nature of the protein fed to the animal makes the estimation of ruminal protein degradability very arduous. At present the in situ technique is the most popular means of predicting ruminal nitrogen (N) degradation. However this procedure is slow, expensive and relies on the use of numerous surgically prepared animals. A number of studies (Assoumani et al., 1992; Aufrère and Cartailler, 1988) have shown that the use of in vitro methods using proteases can predict with reasonable accuracy the extent of protein degradation. The objective of this experiment was to examine the possibility of replacing the in situ technique with an in vitro procedure based on the use of the ficin protease to predict the extent of N degradation.


1999 ◽  
Vol 77 (10) ◽  
pp. 2817 ◽  
Author(s):  
P Iwanchysko ◽  
J J McKinnon ◽  
A F Mustafa ◽  
D A Christensen ◽  
D McCartney

2000 ◽  
Vol 2000 ◽  
pp. 56-56
Author(s):  
J.W. Cone ◽  
A.H. van Gelder ◽  
A.A. Kamman ◽  
V.A. Hindle

The amount of rumen escape protein is commonly determined with the nylon bag technique. However, there is also an in vitro technique described using a protease of Streptomyces griseus (Aufrère et al., 1991; Cone et al., 1996), allowing systematical analysis of protein quality in a large number of samples. The aim of this study was to identify the influences of growing conditions on content of rumen escape protein in grass and grass silage and to investigate the relationships between rumen escape protein determined in vitro and in situ and chemical composition.


1997 ◽  
Vol 77 (3) ◽  
pp. 431-440 ◽  
Author(s):  
Y. Wang ◽  
T. A. McAllister ◽  
D. R. Zobell ◽  
M. D. Pickard ◽  
L. M. Rode ◽  
...  

The effect of micronization of full-fat canola seed on dry matter disappearance (DMD) and total nitrogen disappearance (TND) in the rumen and intestine were investigated. Full-fat canola seed was left untreated (C) or micronized for 1.5 min (M), and left whole (CW, MW) or ground to pass through a 1.25-mm sieve (CG, MG). In vitro gas production from CW and MW were determined at 0, 1, 2, 3, 8, 12, 20, 24, 32, 48, 52, 68 and 72 h. For subsequent studies, CW was hand-cracked (CH) for comparison against MW. In situ DMD and TND from CH, MW, CG and MG were determined after 0, 2, 4, 8, 16, 24, 48 and 96 h of ruminal incubation. The mobile nylon bag technique was used to estimate intestinal digestion (DM and N disappearance) of samples incubated in the rumen for 16 h and in acid-pepsin for 1 h. Scanning electron microscopy revealed the pattern and extent of seed coat rupture from hand-cracking and from micronization to be similar, but micronization-mediated changes to the internal structures were evident in ground samples. Micronization increased (P < 0.05) in vitro gas production from whole canola seed (CW vs. MW), but relative to CH, DMD and TND from MW were lower (P < 0.001) in situ and in the whole digestive tract (P < 0.001). Estimated intestinal DMD and TND did not differ (P > 0.05) between CH and MW. Ruminal DMD and TND from ground seed were reduced (P < 0.05) by micronization (CG vs. MG) in the rumen, but intestinal DMD and TND were increased (P < 0.05 and P < 0.01, respectively), thus in the whole digestive tract, these values did not differ (P > 0.05) between treatments. Micronization reduced potential ruminal protein degradability (P < 0.05) and effective ruminal protein degradability (P < 0.01) of full-fat canola, and in combination with grinding, increased the proportion of protein digestion in the intestine. Key words: Micronization, full-fat canola seed, digestibility, rumen, dairy cow, in situ


1998 ◽  
Vol 22 ◽  
pp. 131-144 ◽  
Author(s):  
T. Hvelplund ◽  
M. R. Weisbjerg

Abstract Expressing the protein value of a food involves measurements of several of its characteristics. Many in vivo studies have shown, that the protein degradability in the rumen varies substantially both between and within foods and therefore estimation of protein degradability in the rumen is an important task in protein evaluation. The most common method used has been the in situ (in sacco, nylon bag) method but many in vitro methods have been introduced and are based on use of either buffer solubility, chemical methods, rumen fluid or enzymes. None of these in vitro methods has proven to be of general use. In further development of in vitro methods as well as the in situ method a major problem is lack of a set of samples with a ‘true’ in vivo degradability which can be used for calibration of alternative methods. Microbial protein synthesis in the rumen has to be related to food characteristics which can be analysed easily. In vitro methods which can predict organic matter digestibility in foods are available and can be used to predict microbial protein synthesis in the rumen. Intestinal digestibility of undegraded dietary protein varies substantially both between and within foods and easy methods to estimate intestinal digestibility are therefore essential. The mobile bag method is easy to use and seems to give reliable results on most foods but requires access to duodenal cannulated animals which prevents this method from being routine. Alternative in vitro methods have been developed but further research is required for validation of these methods on a wide range of foods before they can be accepted for general use.


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