In situ estimation of indigestible compounds contents in cattle feed and feces using bags made from different textiles

Abstract

-The objective of this experiment was to evaluate estimates of concentration of indigestible dry matter (iDM), indigestible neutral detergent fiber (iNDF) and indigestible acid detergent fiber (iADF) in samples of cattle feed and feces processed at different particle sizes (1-, 2-, and 3-mm) using bags made from nylon (50 μm), F57 (Ankom ® ), and nonwoven textile (NWT -100 g/m²) in a in situ evaluation procedure. Eight samples of concentrates, seven samples of forages and two samples of cattle feces were used. The samples were put in the bags according to a ratio of 20 mg of dry matter/cm² of surface by using three bags of each textile for each size of particle, totaling 405 bags, which were submitted to ruminal incubation for 264 hours. The contents of indigestible compounds in the samples were evaluated sequentially. Blank bags were used for microscopic evaluation of textile physical integrity and for evaluation of the physical resistance. The presence of contaminants caused high variability of results of iDM, indicating that its using as internal marker should not be recommended.By using the textiles F57 and NWT, similar estimates for contents of iNDF and iADF were obtained whereas by using nylon (50 μm), the concentration of iNDF was underestimated, possibly because of loss of particles due to its porosity. Nylon presented loss of resistance in all analytical stages, expanding its probality of rupture, especially after extraction with acid detergent. For in situ evaluation of indigestible compounds, it is suggested grinding samples in 2-mm screen sieves.Key Words: F57, internal markers, nylon, non-woven textile, particle size Estimação in situ dos componentes indigestíveis em alimentos e fezes de bovinos com sacos de diferentes tecidos RESUMO -Objetivou-se avaliar as estimativas de concentração de matéria seca (MSi), fibra em detergente neutro (FDNi) e fibra em detergente ácido (FDAi) indigestíveis em amostras de alimentos e fezes bovinas processadas em diferentes tamanhos de partículas (1, 2 e 3 mm) utilizando-se sacos confeccionados com os tecidos nylon (50 μm), F57 (Ankom ® ) e tecido não-tecido (TNT -100 g/m 2 ) em procedimento de avaliação in situ.

Evaluation of ruminal degradation profiles of forages using bags made from different textiles

“…Recently, it has been proposed that NWT could replace F57 in laboratorial analysis of fiber and in procedures for in situ evaluation of indigestible compounds in feeds and cattle feces. That statement was based on similar accuracy between textiles and lower cost of NWT compared with F57 (Valente et al, 2011a;2011b). Facing such perspectives, the comparison between these textiles was performed.…”

“…Generally, greater estimates were obtained by using nylon (Table 3; Figure 2). F57 and NWT present similar physical structure and both textiles are produced by deposition of synthetic fiber without weaving (Casali et al, 2009;Valente et al, 2011a). Recently, it has been proposed that NWT could replace F57 in laboratorial analysis of fiber and in procedures for in situ evaluation of indigestible compounds in feeds and cattle feces.…”

“…One of the main constraints for using textiles in the evaluation of insoluble fibrous compounds is the possibility of particle loss during analytical procedures (Hvelpund & Weisbjerg, 2000;Casali et al, 2009;Valente et al, 2011a). In this context, when samples are processed to be used in incubation procedures, one must seek for a particle size that represents an equilibrium point between control of particles loss and an adequate specific surface for microbial degradation (Valente et al, 2011a).…”

“…Such pattern seems to be, at least partially, the cause of the lower estimates of potentially degradable fraction of NDF when nylon was used ( Figure 3) and could directly affect the estimates of DM fractions (Tables 2 and 3). The broader porosity of nylon has been considered the main cause of its greater losses of particles (Casali et al, 2009;Valente et al, 2011a).…”

“…Firstly, nylon is not recommended for this procedure (Casali et al, 2009;Valente et al, 2011a) because it propitiates great loss of fibrous particles (Figure 3). From this, direct comparisons for evaluating the estimation procedures of undegradable compounds must be done between F57 and NWT.…”