Evaluation of the potential of short term intake rate (STIR) to predict effects of chop length on in vivo parameters in sheep

1999 ◽  
Vol 1999 ◽  
pp. 105-105
Author(s):  
D. Hurst ◽  
D. L. Romney ◽  
A. H. Murray
Keyword(s):  
Particle Size ◽  
Physical Structure ◽  
Gas Production ◽  
Intake Rate ◽  
Short Term ◽  
Physical Form ◽  
Feed Samples

Parameters from in vitro gas production and in situ degradability are often used to predict digestibility and intake in vivo. However, these methods use dried ground feed samples and cannot be expected to estimate the effect of changes in physical form or particle size. Previous work (Romney and Gill 1998) has indicated that short term intake rate (STIR) values showed potential to rank a variety of feeds in terms of their ad libitum dry matter intake, rate of passage and digestibility. Since STIR values are determined on feeds “as offered” it is likely they will reflect the effects of physical structure on in vivo parameters. The present work examines whether measurement of STIR values can be used to predict in vivo responses to changes in particle size distribution in chopped forages.

scholarly journals Comparison of methods used to predict the in vivo digestibility of feeds in ruminants

1999 ◽  
Vol 50 (5) ◽  
pp. 825 ◽  
Author(s):  
S. Kitessa ◽  
G. G. Irish ◽  
P. C. Flinn
Keyword(s):  
Chemical Composition ◽  
Energy Content ◽  
Starch Content ◽  
Gas Production ◽  
Near Infrared Reflectance ◽  
Laboratory Methods ◽  
Feed Samples

Digestibility is a very useful index of the energy content of ruminant feeds, but cheaper and quicker laboratory methods are required as an alternative to the ultimate measure of in vivo digestibility using animals. These methods involve either prediction of digestibility from chemical composition or in vitro and in situ simulation of the digestion process. This review presents a range of chemical and in vitro techniques for predicting digestibility, together with an assessment of their advantages and limitations, particularly the degree to which they account for the sources of variation in in vivo digestibility in ruminants. In situ digestion of feed samples in the actual rumen environment is probably the most accurate of the non in vivo procedures, but is not suitable for routine application. Thein vitro gas production technique offers no advantages in prediction of total tract digestibility, but is useful for screening cereal grains for rate of starch hydrolysis in the rumen. The preferred procedure for routine laboratory prediction of digestibility is the pepsin-cellulase technique, provided amylase is included or high temperature digestion is used for samples high in starch content. Prediction of digestibility from chemical composition is not recommended. The optical technique of near infrared reflectance spectroscopy can be calibrated against any of the methods outlined in this review, and is unsurpassed in terms of speed and repeatability. Direct NIR prediction of in vivo digestibility is also possible, but is limited by the lack of adequate numbers of feed samples with known in vivo values. Future work should be aimed at filling this gap and also improving the accuracy of laboratory methods for predicting the digestibility of low quality feeds.

Phosphofructokinase activity and acidosis during short-term tetanic contractions

1991 ◽  
Vol 69 (2) ◽  
pp. 298-304 ◽  
Author(s):  
Lawrence L. Spriet
Keyword(s):  
Glycolytic Enzyme ◽  
Test Tube ◽  
Mammalian Skeletal Muscle ◽  
Short Term ◽  
Short Supply ◽  
In Vivo Experiments ◽  
Anaerobic Energy

Anaerobic energy production is essential for the production of muscular tension when the demand for energy is greater than can be provided aerobically and when oxygen is in short supply. The largest source of anaerobic energy is from the glycolytic pathway. With sustained tetanic contractions, muscle glycolytic activity is high and hydrogen ions (H+) accumulate while tension production decreases. The increasing [H+] and decreasing tension led to the suggestion that H+ inhibits the activity of the regulatory glycolytic enzyme phosphofructokinase (PFK). Early in vitro work confirmed the H+ sensitivity of PFK in the test tube, indicating that little PFK activity should persist at a pH of 6.9–7.0. However, in situ and in vivo experiments suggested that significant PFK activity was maintained during intense contractions when muscle pH decreased to 6.4–6.6. There are several concerns associated with the application of in vitro findings to in vivo exercise situations: (i) there is little in vitro work in mammalian skeletal muscle with substrate and modulator concentrations representative of exercise, (ii) most in vitro analyses of PFK activity are performed following the dilution of the enzyme in mediums with low protein concentration, and (iii) do the modulators identified in vitro exist in high enough in vivo concentrations at rest and during exercise to contribute to the regulation of PFK? More recent in vitro and in situ PFK experiments have overcome some of these concerns. They confirm that during intense, short-term tetanic contractions, PFK activity is well matched to the ATP demand despite decreases in pH to ~6.4–6.5. A combination of decreased inhibitor (ATP) and increased substrate (fructose 6-phosphate) contents coupled with increases in the contents of several positive modulators may be responsible for the maintained PFK activity. This combination reduces the pH-dependent ATP inhibition of PFK and extends the physiological pH range of the enzyme to the range normally measured during this type of muscular activity.Key words: glycolysis, phosphofructokinase, anaerobic metabolism, acidosis.

Prediction of Digestibility and Intake of Sheep Fed Leguminosae or GRAMINAE Hays: Comparison Between the in Vitro Digestibility, Kinetics of Gas Production or Dry Matter Degradation

1994 ◽  
Vol 1994 ◽  
pp. 103-103
Author(s):  
M.T. Dentinho ◽  
K. Khazaal ◽  
J.M. Ribeiro ◽  
E.R. Ørskov
Keyword(s):  
Dry Matter ◽  
Lolium Multiflorum ◽  
Daily Intake ◽  
Gas Production ◽  
Italian Ryegrass ◽  
In Vitro Digestibility ◽  
Kinetics Of

By using separated values of kinetics of in situ dry matter (DM) degradation or in vitro gas production (Menke and Steingass, 1988) of leguminosae hays, Khazaal et al, (1993) reported high correlation with intake (r= 0.88; r= 0.79) and in vivo DM digestibility (DMD) (r= 0.94; r= 0.88). The aim of the present study was to extend the range of samples used and compare the ability of the 2 stages in vitro digestibility (Tilley and Terry, 1963), the in situ DM degradation or the gas production techniques to predict daily intake (g DM/ kgW0.75) and in vivo DM digestibility (DMD) of 19 leguminous and graminaceous hays fed to sheep.Three harvesting stages (early bloom EB, mid bloom MB or in seed IS) made from lucerne (Medicago sativa), sweet clover (Melilotus segetalis), Persian clover (Trifolium resupinatum), Rye (Secale cereale), Triticale (Triticale hexaploid), oat (Avena stativa) and a pre-bloom (PB) Italian ryegrass (Lolium multiflorum ). Each hay was fed ad libitum to 4 Merino male sheep and their intake and in vivo DMD recorded. Gas production (ml/ 200 mg DM) or in situ DM degradation (g/ 100 g DM) were determined as described by Khazaal et al, (1993) after 6, 12, 24, 48, 72 or 96 h incubation. Measured gas production or DM degradation values were fitted to the equation p=a+b(l-e-ct)(McDonald, 1981) where p is gas production or DM degradation at time t and a, b and c are constants. For nylon bag the washing loss (soluble fraction) was defined as A, the insoluble but fermentable matter was defined as B=(a+b)-A, and c is the rate of fermentation or degradation (Ørskov and Ryle, 1990).

Palatability,in situandin vitronutritive value of dried sainfoin (Onobrychis viciifolia)

2010 ◽  
Vol 148 (6) ◽  
pp. 723-733 ◽  
Author(s):  
H. KHALILVANDI-BEHROOZYAR ◽  
M. DEHGHAN-BANADAKY ◽  
K. REZAYAZDI
Keyword(s):  
Organic Matter ◽  
Dry Matter ◽  
Nutritive Value ◽  
Nutrient Content ◽  
Gas Production ◽  
Metabolizable Energy ◽  
Acid Detergent Fibre

SUMMARYThe current study was conducted to determine chemical composition, nutrient content and availability, metabolizable energy (ME) content and nutritive value of sainfoin hay for ruminants. Three ruminally cannulated Holstein cows were used forin situandin vivoexperiments, to determine rumen degradability and digestibility of sainfoin hay. Apparent total tract digestibility of nutrients was determined with feeding of sainfoin hay as the sole diet to achieve 10% more than maintenance energy requirements. Six Zandi ewes were used in the palatability experiment. Means for dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and condensed tannins (CTs) of sainfoin hay were: 940·4 g/kg and 93·43, 12·13, 47·87, 43·33 and 2·13 g/kg DM, respectively.In situeffective degradability of CP and DM were 0·38 and 0·54 g/g with a ruminal outflow rate of 0·05/h, respectively. OM apparent digestibility was in the range of 0·592–0·689, respectively, for Tilley & Terry and total faecal collection assays. ME content of sainfoin hay, according to different methods (gas production,in vitroandin vivodetermined digestible organic matter in dry matter (DOMD)) was in the range 6·87–10·11 MJ/kg DM. Metabolizable protein (MP) content was 483·4 g/kg CP. Sainfoin was more palatable than alfalfa for sheep. It was concluded that sainfoin has a potential use in ruminant rations, especially if environmental conditions are not suitable for alfalfa production.

A comparison between in vitro digestibility, in situ degradability and a gas production technique for predicting the in vivo digestibility of whole-crop wheat

1998 ◽  
Vol 22 ◽  
pp. 33-35
Author(s):  
A. T. Adesogan ◽  
E. Owen ◽  
D. I. Givens
Keyword(s):  
Nutritive Value ◽  
Gas Production ◽  
In Vitro Digestibility ◽  
Production Technique ◽  
Grass Silage ◽  
Laboratory Techniques

Several published reports on the nutritive value of whole-crop wheat (WCW) have been based on estimations from laboratory techniques, some of which were developed for grass silage. However, there is little information on the accuracy of such estimations. Therefore the aim of this study was to evaluate the suitability of predicting the in vivo digestibility of WCW from various less animal-dependent techniques.

Carboxyfluorescein (CFSE) Labelling of Hepatocytes for Short-Term Localization following Intraportal Transplantation

1994 ◽  
Vol 3 (5) ◽  
pp. 397-408 ◽  
Author(s):  
Hikaru Fujioka ◽  
Peter J. Hunt ◽  
Jacek Rozga ◽  
Guo-Du Wu ◽  
Donald V. Cramer ◽  
...  
Keyword(s):  
Fluorescence Microscopy ◽  
Isolated Hepatocytes ◽  
Facs Analysis ◽  
Short Term ◽  
Tissue Sections ◽  
Donor Cells ◽  
Portal Vein Infusion

Renewed interest in the transplantation of isolated hepatocytes into the liver as a potential therapy for liver disease has stimulated the development of methods for the identification of donor cells within the recipient organ. We describe a method for cellular tagging and in vivo identification of intraportally transplanted hepatocytes using an intracellular fluorescent dye, 5(6)-carboxyfluorescein diacetate, succinimidyl-ester (CFSE). Rat and porcine hepatocytes were isolated and labelled with CFSE. The optimal conditions for labelling consisted of a buffered saline suspension of hepatocytes (5 × 106 cells/mL) in 20.0 μM CFSE incubated for 15 min at 37°C. In vitro, labelled hepatocytes were cultured either on fibronectin-coated chamber slides or in culture flasks. Cultures were evaluated in situ by fluorescence photomicrography or by fluorescence-activated cell sorting (FACS) after cell detachment. Cell viability was assessed serially and cultured, labelled hepatocytes retained the dye for up to 3 wk (last day of study). CFSE did not effect hepatocyte viability and there was no evidence of intercellular diffusion of the dye. In vivo, syngeneic Lewis rats underwent selective portal vein infusion of freshly isolated, labelled hepatocytes (2.0 × 107 cells/2.0 mL saline/animal) into the posterior liver lobes. All recipients were sacrificed 48 h and 96 h later and their livers examined. Transplanted hepatocytes were identified by fluorescence microscopy in tissue sections and by FACS following collagenase digestion of the liver tissue. CFSE persisted in a population of viable, engrafted hepatocytes. FACS analysis demonstrated that 9 ± 3% of the hepatocytes in the posterior liver lobes were labelled 48 and 96 h after transplantation. At 96 h following transplantation, multiple engrafted hepatocytes could be observed by fluorescence microscopy around the central veins. CFSE labelling allows for both in vitro identification and in vivo localization of donor hepatocytes. Furthermore, it appears to be more stable and specific for labelling hepatocytes than other tested dyes (especially DiI).

Rumen degradability of Mongolian pastures: a comparison of in situ and in vitro gas production techniques

1996 ◽  
Vol 1996 ◽  
pp. 227-227 ◽  
Author(s):  
A.H. Murray ◽  
D. Daalkhaijav ◽  
C.D. Wood
Keyword(s):  
Gas Production ◽  
Forest Steppe ◽  
High Mountain ◽  
In Vitro Gas Production ◽  
Production Techniques ◽  
Native Pastures ◽  
The Relationship

In Mongolia animal performance is very much dependent on the quality and quantity of natural grassland available, since certain pastoral animals may obtain as much as 98% of their annual intake from pasture. There have been few studies to date on either in vivo or in vitro degradation of native Mongolian pastures. This paper seeks to investigate the degradation characteristics of native pastures from 2 regions in Mongolia, high mountain and forest steppe. It also investigates the relationship between the in vitro gas production technique and the in sacco technique.

Relationship between in vivo, in situ and in vitro techniques for evaluation of tropical forages in Brazil

2002 ◽  
Vol 2002 ◽  
pp. 141-141
Author(s):  
Ives C.S. Bueno ◽  
Sergio L.S. Cabral Filho ◽  
Liliana L. Oetting ◽  
Mariana C. Machado ◽  
Sarita P. Gobbo ◽  
...  
Keyword(s):  
Low Cost ◽  
Gas Production ◽  
Ease Of Use ◽  
In Vitro Techniques ◽  
Evaluation Systems ◽  
Similar Information ◽  
Tropical Forages

In vivo experiments are the preferred method for ruminant feed evaluation, but they are very expensive, laborious and time-consuming. In situ and in vitro techniques are commonly used as a routine all over the world as a predictor of in vivo results. In situ assays have been the basis of many feed evaluation systems due to its ease of use and low cost. In vitro techniques, such as gas production, give an opportunity to get similar information plus a better description of fermentative kinetics. The aim of this work was to compare data obtained from in vivo, in vitro and in situ assays for the evaluation of three tropical forages used in ruminant nutrition in Brazil.

Relationship between in vitro gas production and in situ degradability for forage components

1998 ◽  
Vol 22 ◽  
pp. 244-246
Author(s):  
T. Ichinohe ◽  
W. J. Shand ◽  
D. J. Kyle ◽  
X. B. Chen ◽  
E. R. Ørskov
Keyword(s):  
Production Rate ◽  
Nutritive Value ◽  
Kinetic Studies ◽  
Gas Production ◽  
Soluble Carbohydrates ◽  
In Vitro Gas Production ◽  
The Relationship

Recently in vitro and in situ techniques have been used for assessing forage nutritive value for ruminants instead of laborious in vivo trials. Although, Blummel and Ørskov (1993) have shown that an in vitro gas production technique gives reliable estimates of forage nutritive value, whether the estimates could be correlated with in situ degradation are not well established. There is little known about the differences in degradation characteristics of neutral-detergent fibre (NDF) and cellular contents (CC: soluble carbohydrates, lipids and crude protein) in the rumen, and also about the relationships between component degradation rate in the rumen and gas production rate for different forages. This is because most in situ kinetic studies have followed the disappearance of insoluble cell wall constituents and comparative studies of in vitro and in situ estimates was not performed sufficiently.The objective of this experiment was to investigate the relationship between in situ degradation of forage components and in vitro gas production rate for the three forages.

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