In vitro techniques to replace in vivo methods for estimating amino acid supply

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.

1998 ◽  
Vol 22 ◽  
pp. 306-308
Author(s):  
M. D. Carro ◽  
E. L. Miller

The estimation of rumen microbial protein synthesis is one of the main points in the nitrogen (N)-rationing systems for ruminants, as microbial protein provides proportionately 0.4 to 0.9 of amino acids entering the small intestine in ruminants receiving conventional diets (Russell et al., 1992). Methods of estimating microbial protein synthesis rely on marker techniques in which a particular microbial constituent is related to the microbial N content. Marker : N values have generally been established in mixed bacteria isolated from the liquid fraction of rumen digesta and it has been assumed that the same relationship holds in the total population leaving the rumen (Merry and McAllan, 1983). However, several studies have demonstrated differences in composition between solid-associated (SAB) and fluid-associated bacteria in vivo (Legay-Carmier and Bauchart, 1989) and in vitro (Molina Alcaide et al, 1996), as well in marker : N values (Pérez et al., 1996). This problem could be more pronounced in the in vitro semi-continuous culture system RUSITEC, in which there are three well defined components (a free liquid phase, a liquid phase associated with the solid phase and a solid phase), each one having associated microbial populations.The objective of this experiment was to investigate the effect of using different bacterial isolates (BI) on the estimation of microbial production of four different diets in RUSITEC (Czerkawski and Breckenridge, 1977), using (15NH4)2 SO4 as microbial marker, and to assess what effects any differences would have on the comparison of microbial protein synthesis between diets.This study was conducted in conjunction with an in vitro experiment described by Carro and Miller (1997). Two 14-day incubation trials were carried out with the rumen simulation technique RUSITEC (Czerkawski and Breckenridge, 1977). The general incubation procedure was the one described by Czerkawski and Breckenridge (1977) and more details about the procedures of this experiment are given elsewhere (Carro and Miller, 1997).


1999 ◽  
Vol 133 (3) ◽  
pp. 335-340 ◽  
Author(s):  
M. BLÜMMEL ◽  
R. MGOMEZULU ◽  
X. B. CHEN ◽  
H. P. S. MAKKAR ◽  
K. BECKER ◽  
...  

The relationship between variations in in vitro microbial biomass production and microbial protein supply to the host animal was examined in 13 Malawian goats fed on stover leaves from two varieties of maize at Bunda College, Malawi, in 1995. The in vitro parameters were analysed based on the concept of the partitioning factor (PF) which is obtained by the combination of gas volume measurements with determinations of the amount of substrate truly degraded. The PF reflects substrate-dependent variation in the in vitro partitioning of degraded substrate between short chain fatty acids (SCFA), gases and microbial biomass. The in vivo microbial protein synthesis was estimated by the urinary excretion of the purine derivatives (PD) allantoin, uric acid and xanthine + hypoxanthine. For the two types of stover leaves examined, the higher microbial efficiency of one variety in vitro was reflected by different PD excretions on practically identical digestible dry matter intakes in vivo. It is concluded that substrate-dependent variations in microbial efficiencies as detected by the PF are also evident and relevant for in vivo microbial protein synthesis.


1998 ◽  
Vol 22 ◽  
pp. 262-263
Author(s):  
S. Fakhri ◽  
A. R. Moss ◽  
D. I. Givens ◽  
E. Owen

The in situ and in vitro techniques have been adopted to estimate the degradability of organic matter (OM) in the rumen on the basis that this provides an estimate of ATP for microbial protein synthesis. However this assumption may be incorrect since ATP production requires the fermentation of degraded carbohydrate and Beever (1993) has shown that some degraded hexose can be used synthetically without ATP production. In addition, degraded OM from protein is likely to produce less ATP than the same amount of degraded carbohydrate. The gas production (GP) technique measures end products of fermentation and may be a better guide to ATP production. On the assumption that the in situ and in vitro techniques provide satisfactory estimation of OM degradability, the work discussed here used the GP technique to estimate the effective unfermentable OM fraction of the degraded OM (EUFDOM) for a range of concentrate foods.


2011 ◽  
Vol 11 (2) ◽  
pp. 29-34 ◽  
Author(s):  
Novita Hindratiningrum ◽  
Muhamad Bata ◽  
Setya Agus Santosa

Products of rumen fermentation and protein microbial of dairy cattle feed with rice bran ammonization and some feedstuffs as an energy sourcesABSTRACT. This study aims to examine the energy sources of feed ingredients that can increase the production of Volatile Fatty Acids (VFA), N-NH3, microbial protein synthesis, total gas production and metabolic energy. The material used is as a source of rumen fluid inoculum from Frisian Holstein cows (FH) females, amoniasi rice straw, salt, mineral mix brand "Ultra Minerals' production Eka Farma Semarang, onggok wet and dry, corn, and rice bran. Observed variable is the concentration of (VFA), N-NH3, rumen microbial protein synthesis, and total gas production. Based on the analysis of diversity seen any significant effect (P0.05) on total VFA concentration, N-NH3 and total gas but had no effect (P0.05) on microbial protein synthesis. Conclusion of research is the provision of energy sources with rice bran treatment, onggok wet and dry corn flour can be used as fermentable carbohydrates on feed hay amoniasi in vitro.


1979 ◽  
Vol 49 (1) ◽  
pp. 163-168 ◽  
Author(s):  
J. E. Williams ◽  
G. A. McLaren ◽  
T. R. Smith ◽  
G. C. Fahey

1987 ◽  
Vol 252 (5) ◽  
pp. H906-H915 ◽  
Author(s):  
T. E. Gayeski ◽  
R. J. Connett ◽  
C. R. Honig

Probability distributions of myoglobin (Mb) saturation and intracellular PO2 were determined with subcellular spatial resolution in dog gracilis muscles during steady-state twitch contraction at 5-100% of maximal rate of O2 consumption (VO2). Calculations (Clark, A., and P. A.A. Clark. Biophys. J. 48: 931-938, 1985) and measurements (Gayeski, T. E. J., and C. R. Honig. Adv. Exp. Med. Biol. 200: 487-494, 1986) indicate that the PO2 in equilibrium with Mb is virtually identical to the PO2 at cytochrome aa3. Median intracellular PO2 and PO2 in the lower tails of probability distributions were poorly correlated with VO2. The variability of cell PO2 was greatly diminished when median PO2 was less than the PO2 for half saturation of MB, since Mb acts as a PO2 buffer. The lower tails of PO2 distributions contained almost no anoxic loci even when median PO2 was less than 1 Torr. VO2 was well correlated with the concentration ratio of phosphocreatine to free creatine (PCr/Crf) over a wide range of PO2. PO2 greater than or equal to 0.5 Torr supported maximal VO2 and energy demand. We conclude that 1) the mechanism of action of cytochrome aa3 is the same in red muscle in vivo as in mitochondria in vitro, and 2) an upper bound on the apparent Michaelis constant for maximal VO2 of red muscle is approximately 0.06 Torr.


Pastura ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 47
Author(s):  
Afduha Nurus Syamsi ◽  
Fransisca Maria Suhartati ◽  
Wardhana Suryapratama

An experiment was aimed to assess the use of the legume leaf as a source of protein feedstuff and levels of synchronization protein-energy (SPE) index in the diet of cattles on ammonia (N-NH3) and microbial protein synthesis (MPS). In vitro techniques was done. The research was used a completely randomized design (CRD), with factorially pattern (2x3), the first factor was the two species of legume (Sesbania leaves and Leucaena leaves) and the second factor was the three level of the SPE index (0.4, 0.5, and 0.6), there were 6 treatment combinations and each was 4 replicates. The results showed that no interaction between legume with SPE index, but each factor was significantly effect (P<0.05) on N-NH3 of rumen fluid and MPS. The research concluded that Leucaena leaf is a legume that is better than Sesbania leaf in terms of their ability toincrease MPS. SPE index is the best in producing MPS at level 0.6. Key words: Legume, synchronization of protein and energy index, ammonia, microbial protein synthesis


Sign in / Sign up

Export Citation Format

Share Document