Evaluation of a mathematical model of rumen digestion and an in vitro simulation of rumen proteolysis to estimate the rumen-undegraded nitrogen content of feedstuffs

1. Twelve grain mixtures, one lucerne (Medicago sativa) hay and one maize silage which had been used in mixed diets for which dietary nitrogen undegraded in the rumen (UDN) had been estimated with duodenally-cannulated cows, were studied. Total N in the feeds was fractionated into pool A (N soluble in borate–phosphate buffer), pool B (total N–(pool A + pool C)) and pool C (acid-detergent-insoluble N or residual N after 24 h incubation in protease solution).2. N solubilization in protease solution containing 6·6 units/ml (substrate-saturating enzyme concentration) indicated the presence of subfractions in pool B, with different rates of solubilization. Such subfractions were not detectable from in situ, Dacron bag, estimates of N solubilization.3. UDN was estimated using a dynamic mathematical model and rate-constants obtained from N solubilization in protease solution or in situ.For three grain mixtures tested using the protease technique the model predicted UDN values of 7, 10 and 12% compared with values of 47, 66 and 59% estimated in vivo. The full range of experimental feeds was tested using the in situtechnique and UDN values predicted by the model were used to derive UDN values for twelve mixed diets. The latter values were significantly but not closely correlated with those determined in vivo (r2 0·41, P < 0·05).4. An attempt was made to simulate rumen proteolysis in vitro by choosing a protease enzyme concentration (0·066 units/ml) providing a proteolytic activity similar to that of whole rumen fluid. The experimental samples of feed were subjected to simulated rumen proteolysis for 18 or 48 h to resemble the mean retention times in the rumen for grain mixtures and roughages respectively. The residual N at the end of incubation was considered as an estimate of UDN. The UDN values estimated from simulated rumen proteolysis and those determined in vivo for twelve mixed diets were in close agreement (r2 0·61, P < 0·01).5. Simulated rumen proteolysis can serve as a simple, rapid and sensitive method to estimate UDN in a variety of feedstuffs.

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In vitro estimation of rumen fermentable organic matter using rumen fluid and a cell free preparation of rumen fluid

Netherlands Journal of Agricultural Science ◽

10.18174/njas.v42i4.593 ◽

1994 ◽

Vol 42 (4) ◽

pp. 343-356 ◽

Cited By ~ 3

Author(s):

J.W. Cone ◽

A.H. Van Gelder ◽

E.T. Veerman ◽

A.M. Van Vuuren

Keyword(s):

Organic Matter ◽

Rumen Fluid ◽

Good Prediction ◽

Feed Composition ◽

In Vitro Methods ◽

In Situ Method ◽

A Cell

The amount of microbial protein leaving the rumen is considered as a function of the amount of rumen-fermentable organic matter (FOM) in the rumen. FOM can be calculated using tables, or estimated by in situ incubation, but both methods have some drawbacks. In vitro methods were therefore developed to estimate FOM, using fresh rumen fluid or a cell-free preparation of rumen fluid. Results were compared with the in situ method and a method using chemical feed composition. The in vitro methods gave a good prediction of the in situ estimation of FOM for the majority of feeds. For some feeds rich in starch or fat, the correlation was poor. Because no in vivo data of FOM were available, it could not be determined whether the in vitro or in situ methods gave false results. However, arguments suggest that the in situ method is not suitable for some feeds.

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Nutritional assessment of waste of cassava starch extraction dried in cattle feed

Semina Ciências Agrárias ◽

10.5433/1679-0359.2016v37n4supl1p2653 ◽

2016 ◽

Vol 37 (4Supl1) ◽

pp. 2653

Author(s):

Tatiane Fernandes ◽

Maximiliane Alavarse Zambom ◽

Deise Dalazen Castagnara ◽

Rodrigo Cezar dos Reis Tinini ◽

Eduardo Augusto da Cruz ◽

...

Keyword(s):

Nutrient Intake ◽

Nutritional Assessment ◽

Rumen Fluid ◽

Ammonia Concentration ◽

Cassava Starch ◽

In Vitro Digestibility ◽

Cattle Feed

This study aimed to evaluate the digestive power of waste of cassava starch extraction dried (WCSEd) and corn, in addition to determining the appropriate level of WCSEd to replace corn in the diet of cattle. Studies to evaluate the in vitro digestibility and in situ degradability were performed. The study used four cattle with rumen cannula, individually fed with diets containing increasing levels (0, 33, 66 and 100%) of WCSEd to replace corn, to evaluate the dry matter and nutrient intake and digestibility, pH and ammonia concentration of rumen fluid. The WCSEd showed differences in the in vitro digestibility of DM, OM and NDF (P < 0.05) compared to corn, but did not change the NDT and in situ degradability. As for in vivo reviews, the DM and nutrient intake was influenced by treatments in decreasing order, resulting in changes in the digestibility of DM, OM and NDT of diet, and a decreased concentration of N-NH3, but the pH was not affected. The residue from the extraction of cassava starch showed lower in vitro digestibility; however, ruminal degradability did not differ from corn. Their use in ruminant feed reduces the intake and degradation of feed, but improves the use of N-NH3 in the rumen.

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Relationship between in vitro solubility and rumen degradability of forage nitrogen

BSAP Occasional Publication ◽

10.1017/s0263967x00033073 ◽

1998 ◽

Vol 22 ◽

pp. 344-345

Author(s):

D. M. Komwihangilo ◽

E. R. Deaville ◽

D. I. Givens ◽

E. Owen

Keyword(s):

Rumen Fluid ◽

Exponential Model ◽

Internal Diameter ◽

Fresh Sample ◽

Total N ◽

Freeze Dried ◽

Outflow Rate ◽

Kjeldahl Method

It is widely accepted that robust and accurate in vitro techniques are required to predict the proportion of food nitrogen (N) degraded in the rumen. One such technique is to estimate the solubility of food N. In these experiments, relationships between solvent soluble N and in situ rumen degradability of forage N were investigated.Samples of 11 fresh grasses (FG) (mainly perennial ryegrass) and their corresponding silages (GS) were used. GS was prepared from material ensiled in laboratory scale silos for 90 days. Prior to the experiments, FG and GS samples were initially hand chopped to approximately 1 cm lengths. In the in situ study a fresh sample equivalent to 0-5 g DM was weighed into polyester bags (pore size 43 μ 200 X 90 mm internal diameter). Duplicate bags for each of FG or GS were incubated in the rumen of three wethers for 0, 3, 8, 16, 24, 45 and 72 h. The incubated residues including the 0 h samples were washed in a washing machine and freeze-dried for 48 h. Rumen degradability characteristics and effective degradability (ED, at rumen outflow rate of 0.08 per h) of N were calculated using the exponential model of Ørskov and McDonald (1979). In vitro solubility of N (S) was determined by incubating for 1 h (at room temperature) the fresh sample (0.5 g on dry matter basis) in each of the four solvents: Borate phosphate buffer (BFB), Durand's buffer (DB), clarified rumen fluid (CRF) and distilled water within a balanced three way factorial design (three operators; four solvents; 11 forages; Deaville et al., 1997). Residues from S were filtered under vacuum and the filter paper plus residue were oven dried for 18 h at 100°C. All samples and residues were analysed for total N using Kjeldahl method (Ministry of Agriculture, Fisheries and Food, 1986). Factorial analysis on the general linear model (Minitab®, 1994) was used in the analysis of variance(ANOVA) for in vitro data and regression analyses of in situ and in vitro data were performed (Minitab®, 1994). Only the regression results are reported here.

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Métodos de análise da composição química e valor nutricional de alimentos para ruminantes

Research Society and Development ◽

10.33448/rsd-v10i10.19047 ◽

2021 ◽

Vol 10 (10) ◽

pp. e523101019047

Author(s):

Chrislanne Barreira de Macêdo Carvalho ◽

Gabriel Miranda Macambira ◽

Ana Carolina Ferreira dos Santos ◽

Helia Sharlane de Holanda Oliveira ◽

Dayane Albuquerque da Silva ◽

...

Keyword(s):

Total N

A análise dos alimentos constitui um dos principais fatores observados na nutrição animal. A forma mais eficiente de identificação do teor de nutrientes dos alimentos, é através da composição química e valor nutritivo. Na quantificação analítica do valor nutritivo dos alimentos, os principais parâmetros utilizados são: matéria seca (MS), métodos de secagem em estufa, forno de micro-ondas e destilação com tolueno (silagens); matéria mineral (MM), método da incineração em altas temperaturas em mufla; proteína bruta (PB) ou nitrogênio total (N), método Dumas, Linder, Nessler, e Kjeldahl (padrão); fibra detergente neutro (FDN) e fibra detergente ácido (FDA), método Van Soest, com adaptações de equipamentos; lignina, método hidrólise ácida (padrão), com permanganato de potássio, Klason, e lignina solúvel em brometo de acetila; e digestibilidade, métodos in vivo, in situ, in vitro, e marcadores de digestibilidade. No entanto, estes podem ser onerosos, caros e demandar bastante tempo. Como método alternativo e indireto, tem-se a espectrometria de reflectância no infravermelho próximo (NIRS), que possui vantagens com custos, rapidez, usa um pequeno número de amostras e amostragem não destrutiva, é multiparamétrico, e não poluente. Considerando as diversas variáveis que podem ser utilizadas para determinação do valor nutritivo dos alimentos para ruminantes e a gama dos métodos analíticos disponíveis na literatura, cabe ao observador adotar aquele que melhor convém ao objetivo proposto, levando em consideração o tipo de alimento, custo, disponibilidade de reagentes, materiais, equipamentos, e animais à disposição. A metodologia adotada foi um estudo descritivo, resultando em uma revisão bibliográfica embasada em artigos científicos mundiais.

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Monitoring digestibility of forages for herbivores: a new application for an old approach

Canadian Journal of Zoology ◽

10.1139/cjz-2014-0207 ◽

2015 ◽

Vol 93 (3) ◽

pp. 187-195 ◽

Cited By ~ 5

Author(s):

L.L. VanSomeren ◽

P.S. Barboza ◽

D.P. Thompson ◽

D.D. Gustine

Keyword(s):

Dry Matter ◽

Rumen Fluid ◽

Nutrient Supply ◽

Nutrient Digestibility ◽

Total N ◽

In Vitro Method ◽

Microbial Sources ◽

In Sacco

Ruminant populations are often limited by how well individuals are able to acquire nutrients for growth, maintenance, and reproduction. Nutrient supply to the animal is dictated by the concentration of nutrients in feeds and the efficiency of digesting those nutrients (i.e., digestibility). Many different methods have been used to measure digestibility of forages for wild herbivores, all of which rely on collecting rumen fluid from animals or incubation within animals. Animal-based methods can provide useful estimates, but the approach is limited by the expense of fistulated animals, wide variation in digestibility among animals, and contamination from endogenous and microbial sources that impairs the estimation of nutrient digestibility. We tested an in vitro method using a two-stage procedure using purified enzymes. The first stage, a 6 h acid–pepsin treatment, was followed by a combined 72 h amylase–cellulase or amylase–Viscozyme treatment. We then validated our estimates using in sacco and in vivo methods to digest samples of the same forages. In vitro estimates of dry matter (DM) digestibility were correlated with estimates of in sacco and in vivo DM digestibility (both P < 0.01). The in vitro procedure using Viscozyme (r2 = 0.77) was more precise than the in vitro procedure using cellulase (r2 = 0.59). Both procedures can be used to predict in sacco digestibility after correcting for the biases of each method. We used the in vitro method to measure digestibility of nitrogen (N; 0.07–0.95 g/g), which declined to zero as total N content declined below 0.03–0.06 g/g of DM. The in vitro method is well suited to monitoring forage quality over multiple years because it is reproducible, can be used with minimal investment by other laboratories without animal facilities, and can measure digestibility of individual nutrients such as N.

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In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100083035 ◽

1978 ◽

Vol 36 (2) ◽

pp. 434-435

Author(s):

D. Reis ◽

B. Vian ◽

J. C. Roland

Keyword(s):

Cell Wall ◽

Self Assembly ◽

Plant Cell Wall ◽

Higher Plants ◽

Three Dimensional ◽

Cytochemical Study ◽

Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

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Evaluation of Structure-Controlled Silk Fibroin Coatings for Orthopedic Infection and In-Situ Osteogenesis: In Vitro and In Vivo

SSRN Electronic Journal ◽

10.2139/ssrn.3600190 ◽

2020 ◽

Author(s):

Wenhao Zhou ◽

Teng Zhang ◽

Jianglong Yan ◽

QiYao Li ◽

Panpan Xiong ◽

...

Keyword(s):

Silk Fibroin ◽

Orthopedic Infection

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Phase Sensitive Biodegradable Polymer Based In situ Implant of Olanzapine for Depot Injectable Formulation: In vitro Release and In vivo Absorption in Rats

Current Pharmaceutical Analysis ◽

10.2174/1573412911666150408223837 ◽

2015 ◽

Vol 11 (4) ◽

pp. 286-291 ◽

Cited By ~ 1

Author(s):

Fahad Pervaiz ◽

Mahmood Ahmad ◽

Ghulam Murtaza

Keyword(s):

Biodegradable Polymer ◽

Injectable Formulation ◽

Phase Sensitive ◽

In Situ Implant

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Development of In Situ Self-Assembly Nanoparticles to Encapsulate Lopinavir and Ritonavir for Long-Acting Subcutaneous Injection

Pharmaceutics ◽

10.3390/pharmaceutics13060904 ◽

2021 ◽

Vol 13 (6) ◽

pp. 904

Author(s):

Irin Tanaudommongkon ◽

Asama Tanaudommongkon ◽

Xiaowei Dong

Keyword(s):

Sustained Release ◽

Trough Concentration ◽

Self Assembly ◽

Subcutaneous Injection ◽

Drug Loading ◽

Entrapment Efficiency ◽

Long Acting

Most antiretroviral medications for human immunodeficiency virus treatment and prevention require high levels of patient adherence, such that medications need to be administered daily without missing doses. Here, a long-acting subcutaneous injection of lopinavir (LPV) in combination with ritonavir (RTV) using in situ self-assembly nanoparticles (ISNPs) was developed to potentially overcome adherence barriers. The ISNP approach can improve the pharmacokinetic profiles of the drugs. The ISNPs were characterized in terms of particle size, drug entrapment efficiency, drug loading, in vitro release study, and in vivo pharmacokinetic study. LPV/RTV ISNPs were 167.8 nm in size, with a polydispersity index of less than 0.35. The entrapment efficiency was over 98% for both LPV and RTV, with drug loadings of 25% LPV and 6.3% RTV. A slow release rate of LPV was observed at about 20% on day 5, followed by a sustained release beyond 14 days. RTV released faster than LPV in the first 5 days and slower than LPV thereafter. LPV trough concentration remained above 160 ng/mL and RTV trough concentration was above 50 ng/mL after 6 days with one subcutaneous injection. Overall, the ISNP-based LPV/RTV injection showed sustained release profiles in both in vitro and in vivo studies.

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