TWO TECHNIQUES FOR MEASURING NEUTRAL DETERGENT (NDF) AND ACID DETERGENT FIBERS (ADF) IN FORAGES AND BY -PRODUCTS (DOS TÉCNICAS PARA DETERMINAR FIBRA NEUTRO DETERGENTE (FND) Y FIBRA ÁCIDO DETERGENTE (FAD) EN FORRAJES Y SUBPRODUCTOS)

Contreras

Description

Abstract
Twenty samples of forages and byproducts were analysed for NDF and ADF, using a simplified version of ANKOM procedure utilizing a poliester bag (PBT) and the method of Van Soest (VST). The values of determination coeficient (R2 ) were 0.74 and 0.73 for NDF and ADF respectively. The average values obtained with both methods ranged from 64.67 to 65.22 p.100 for NDF and from 54.54 to 45.33 p.100 for ADF. No significant differences were found between PBT and VST for NDF, but for ADF they were significant (p<0.05). The PBT method might be useful to laboratories with limited resources, but the variation factors affecting it, must be detected and standarized and this way quantifying the intra e inter-laboratories related errors.
Resumen
Sobre 20 muestras de forrajes y subproductos se determinó fibra FND y FDA mediante una versión simplificada del procedimiento ANKOM con bolsas de poliéster (PBT) y el método tradicional de Van Soest (VST) obteniendo valores del coeficiente de determinación (R2 ) de 0,74 y 0,73 para FND y FAD respectivamente. Los valores medios para todas las muestras analizadas oscilaron entre 64,67 y 65,22 p.100 para FND y entre 54,54 y 45,33 p.100 para FAD. No se encontraron diferencias entre PBT y VST para NDF pero si para FAD (p<0,05). El método PBT, podría ser de gran utilidad en laboratorios con recursos limitados pero es necesario detectar y estandarizar los factores de variación que lo afectan y cuantificar los errores intra e interlaboratorios asociados al mismo.

Informations

• Publié par: erevistas
• Publié le: 01 janvier 1999
• Nombre de lectures: 14
• Langue: English

Extrait

NOTA BREVE
TWO TECHNIQUES FOR MEASURING NEUTRAL DETERGENT
(NDF) AND ACID DETERGENT FIBERS (ADF) IN FORAGES
AND BY PRODUCTS
DOS TÉCNICAS PARA DETERMINAR FIBRA NEUTRO DETERGENTE (FND) Y FIBRA
ÁCIDO DETERGENTE (FAD) EN FORRAJES Y SUBPRODUCTOS
Contreras Lara, D., L. Gutiérrez Chávez, I. Valdivia Macedo,
R. Govea Casares and J.T. Ramírez Carrillo
Universidad de Colima. Facultad de Medicina Veterinaria y Zootecnia. Crucero de Tecomán. Col. Apartado
postal No. 36. Tecomán 28100. Colima. México.
ADDITIONAL KEYWORDS PALABRAS CLAVE ADICIONALES
ANKOM procedures. Van Soest Method. Procedimiento ANKOM. Método de Van Soest.
SUMMARY
Twenty samples of forages and byproducts tradicional de Van Soest (VST) obteniendo valo
2 were analysed for NDF and ADF, using a simplifiedres del coeficiente de determinación (R ) de 0,74
version of ANKOM procedure utilizing a poliester y 0,73 para FND y FAD respectivamente. Los
bag (PBT) and the method of Van Soest (VST). valores medios para todas las muestras analiza
2 The values of determination coeficient (R ) were das oscilaron entre 64,67 y 65,22 p.100 para FND
0.74 and 0.73 for NDF and ADF respectively. The y entre 54,54 y 45,33 p.100 para FAD. No se
average values obtained with both methods encontraron diferencias entre PBT y VST para
ranged from 64.67 to 65.22 p.100 for NDF and NDF pero si para FAD (p<0,05). El método PBT,
from 54.54 to 45.33 p.100 for ADF. No significant podría ser de gran utilidad en laboratorios con
differences were found between PBT and VST recursos limitados pero es necesario detectar y
for NDF, but for ADF they were significant estandarizar los factores de variación que lo
afectan y cuantificar los errores intra e inter (p<0.05). The PBT method might be useful to
laboratories with limited resources, but the laboratorios asociados al mismo.
variation factors affecting it, must be detected
and standarized and this way quantifying the
INTRODUCTIONintra e inter laboratories related errors.
The procedure for fiber analysis
RESUMEN (Van Soest, 1963; Van Soest and Wine,
1967) is based on the ability of detergent
Sobre 20 muestras de forrajes y subpro solution to solubilize non fibrous
components and separate the fiber byductos se determinó fibra FND y FDA mediante
una versión simplificada del procedimiento filtration, as particulate material. The
ANKOM con bolsas de poliéster (PBT) y el métodoAnkom company developed equipment
Arch. Zootec. 48: 351 354. 1999.CONTRERAS LARA ET AL.
to improve filtration enclosing the NDF or ADF analyses, 10 ml of the
sample in a polyester bag and placing it detergent solution (prepared according
into the detergent solution (Komarek, to Goering and Van Soest, 1970) per
1993). However, the equipment is bag were added. 4) 2 ml of decalin
expensive. The present paper reports (decahydronaphthalene) per 100 ml of
the development of a procedure for detergent solution were added to con
NDF and ADF analyses without trol foaming. 5) The flask was heated
requiring special equipment to carry keeping temperature between 95 and
out digestion and filtration. 100 °C. 6) After 60 minutes for NDF
and 70 minutes for ADF the bags were
taken out and immediately washed with
MATERIAL AND METHODS boiling water until they were free of
any detergent solution. Then they were
A thermometer, a 1l round flask, a rinsed with acetone 3 or 4 times and
universal support, a Bunsen burner, oven dried overnight or by leaving them
and some polyester bags as specific 8 hours at 100 °C, and weighed. 7)
materials were used in the PBT. Bags Percentages of NDF and ADF were
were made in the authors laboratory ofcalculated taking into account the
polyester with an uniform pore size ofweights of polyester bag, the sample
250 mm and 1,600 pore/cm . They were and residues after digestion.
5x6 cm and were made by suturing A comparative study using the
three sides with thread of the same sequential method (ADF after NDF)
material. The unsealed side of the bag was carried out at another laboratory
was used to introduce the sample. according to the original Goering and
The weight loss of the bags caused Van Soest (1970) procedures (VST).
by the effect of detergent solutions and
heat sealing were considered in the
computation of the data. RESULTS AND DISCUSSION
The temperature during digestion
was maintained in a range from 97 to NDF DETERMINATION WITH PBT AND VST
101°C by reducing the flame size and Mean values for NDF analysis with
avoiding air currents. Vapor formation PBT and VST procedures are in table
and subsequent expansion were I. Out of 11 samples, the difference
eliminated by reducing the temperature between the two procedures is less
of the detergent solution. than 4.88 p.100. Seven PBT samples
NDF and ADF PBT analyses showed higher values than the VST
required the following procedure: 1) analysis whereas only 4 samples
The polyester bag was weighed at returned greater values for VST.
constant weight. 2) The bag was filled The NDF values for both, PBT and
with approximately 0.1 g of dry sampleVST, showed a coefficient of deter
2 using fifteen bags for fodder and heat mination R = 0.74
sealed using a low flame from a Bunsen
burner. 3) The bags were put into the PBT AND VST DETERMINATION OFADF
1l ball flask; then, according to the Table I compares the ADF values
Archivos de zootecnia vol. 48, núm. 183, p. 352.TECHNIQUES FOR MEASURING NDF AND ADF IN FORAGES
Table I . NDF (neutral detergent fiber) and ADF (acid detergent fiber) determination ( p. 100)
polyester bag technique (PBT) and original procedures (VST) . (Determinación de fibra neutro
y ácido detergente por la técnica de la bolsa de poliéster y el método tradicional).
NDF (neutral detergent fiber) ADF (acid detergent fiber)
PBT VST PBT VST
Sample Average SD Average SD d Average SD Average SD d
Medicago sativa
Alfalfa leaves 29.76 1.23 27.76 0.55 2.00 21.93 1.63 19.32 2.01 2.61
Alfalfa stalk 47.80 2.04 46.58 2.70 1.22 42.62 1.19 46.55 1.44 3.93
Cocus nucifera
Coconut tow 91.41 2.80 88.50 1.64 2.91 94.99 4.06 77.70 1.73 17.29
Zea mais
Corn bract 80.10 1.52 90.30 9.70 0.2 64.24 3.78 57.18 7.05 7.06
Corn cob 54.99 4.33 37.73 5.50 17.26 23.36 1.70 12.66 9.50 10.07
Corn leaves 67.50 2.34 69.16 1.24 1.66 56.83 2.63 46.59 3.33 10.24
Corn rachis cob 82.65 1.27 91.25 1.30 8.6 74.46 2.18 50.90 3.00 23.56
Corn stalk 72.92 1.86 78.54 4.31 5.62 64.29 2.52 46.55 3.06 17.74
Guazuma ulmifolia
Guasima leaves 33.71 2.01 32.03 1.23 1.68 21.33 3.12 25.12 2.10 3.79
Panicum maximum
Guineagrass 81.78 2.48 77.33 2.40 4.45 75.11 3.27 54.33 9.43 20.78
Sorghum halepensis
Johnsongrass 62.06 1.96 70.12 4.02 8.06 43.93 2.28 44.18 2.91 0.25
Leucaena leucocephala
Leucaena leaves 34.14 2.71 34.51 2.50 0.37 23.83 2.26 23.80 1.29 0.03
Sorghum vulgare Pers
Maicena leaves 60.66 1.44 67.78 4.61 7.12 51.22 2.01 44.61 1.01 6.61
Oryza sativa
Rice husk 83.58 2.29 83.10 2.02 0.48 80.73 2.08 79.00 3.10 1.73
Rice straw 66.82 2.23 67.88 3.16 1.06 58.72 2.74 60.61 5.92 1.89
Sorghum vulgare
Sorghum ear 72.49 1.97 43.17 9.30 29.32 56.53 1.55 30.26 8.12 26.27
Sorghum leaves 64.06 1.56 67.36 1.00 3.3 49.79 1.49 38.78 3.87 11.01
Saccharum officinarum
Sugarcane bagasse64.48 1.76 87.42 6.30 22.94 56.44 1.46 63.70 6.30 7.26
Sugarcane ear 76.51 1.74 71.63 1.96 4.88 71.91 2.11 45.06 10.16 26.85
Sugarcane leaves 66.06 0.91 72.38 3.18 6.32 58.53 2.46 39.79 3.18 18.74
d = Diferences between PBT and VST
obtained with PBT and VST. Differen sugarcane bagasse showed a lower
ces ranged from 6,6 to 26.8 p.100 for average when using PBT. The ADF
13 samples. Out of these, 12 samples values for both PBT and VST showed
2 turned higher values for VST, and only a coefficient of determination R = 0.73.
Archivos de zootecnia vol. 48, núm. 183, p. 353.CONTRERAS LARA ET AL.
In general, the modifications made with respect to VST, but smaller than
when using PBT involved the manner those reported by Komarek et al.
in wich digestion was carried out, (1994) for the NDF and ADF analysis
filtration, and the washing of the with FBT (filter bag technique) and
samples. A correction was made when with the Goering and Van Soest (1970)
NDF and ADF percentages had been procedures. They also report a SD of
calculated because a weight loss of 7 for the NDF values for the FBT. In
0.37 p.100 was observed in the this work, results show good precision
polyester bag due to the effect of as seen by the SD of 4.3 and 4.0 for
detergent solution and temperature. NDF and ADF values from PBT.
Some factors may cause variation The precision achieved shows that
in both, NDF and ADF analysis: the PBT is a less expensive option for
amount of sample, the detergent analysis since it does not need
solution/sample rate, temperature and sophisticated equipment. Furthermore,
time for digestion (Komarek, 1993). with PBT it is possible to use small
Lee and Prosky (1992) compared amounts of sample, wich may save
the AOAC procedures for fiber detergent solutions. With PBT, as many
analysis. The discrepancies (ranging analyses as bags can be contained in
from 12 to 60 p.100) were caused by the matrass without having saturation.
problems in the filt