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It was carried out two assays with the purpose of evaluating the mobile nylon bag technique and the method of total feces collection method in the estimative of the apparent digestibility of starch and other nutrients in high moisture sorghum grain silages in horses. Four adult horses of mixed origin at the age of 7 years and average body weight of 330 kg were used. In the first assay, the digestibility of the nutrients in the silage of high moisture sorghum grain with low level of tannin was evaluated by utilizing the total feces collection and the mobile nylon bag technique with silage samples ground in three particle sizes. In the second assay, the two methods were used for estimating the digestibility of the nutrients of the silage of high moisture sorghum grain with high level of tannin. A randomized block experimental design was used, considering each animal as a block. The disappearance of the nutrients, in the naylon bag, of the samples of the high moisture sorghum grain silages ground in three particle sizes of 1, 8 and 13 mm was also evaluated in laboratory. Daily dry matter intake was 2.0% of the body weight and test diets were made up of 30% of high moisture sorghum grain silages and 70% of coast-cross hay. The coefficients of dry matter digestibility, energy and protein of both silages were similar among the total feces collection method and the mobile nylon bag technique when 8-mm feed samples were used. The coefficient of starch digestibility was similar among the methods when sorghum samples were ground at 1 mm in the mobile nylon bag technique. Reduced particle size increased the nutrient losses of the nylon bags after washing in water. The mobile nylon bag technique allows to estimate the digestibility coefficient of nutrients, however, further studies for evaluation of particle size of the samples should be conducted.Foram realizados dois ensaios com o objetivo de avaliar a técnica do saco de náilon móvel e o método de coleta total de fezes na estimativa da digestibilidade aparente do amido e de outros nutrientes em silagens de grãos úmidos de sorgo em equinos. Foram utilizados quatro cavalos adultos sem raça definida, com 7 anos de idade e peso corporal médio de 330 kg. No primeiro ensaio, avaliou-se a digestibilidade dos nutrientes da silagem de grãos úmidos de sorgo com baixo teor de tanino utilizando a coleta total de fezes e a técnica do saco de náilon móvel com amostras da silagem moídas em três granulometrias. No segundo ensaio, foram utilizados os dois métodos na estimativa da digestibilidade dos nutrientes da silagem de grãos úmidos de sorgo alto tanino. O delineamento experimental foi o de blocos casualizados, considerando cada animal um bloco. Também foi avaliado em laboratório o desaparecimento, nos sacos de náilon, dos nutrientes das amostras das silagens de grãos de sorgo úmidos moídas em três granulometrias (1, 8 e 13 mm). A ingestão diária de matéria seca foi de 2,0% do peso corporal, e as dietas-teste foram compostas de 30% de silagem de grãos úmidos de sorgo e 70% de feno de coast-cross. Os coeficientes de digestibilidade da matéria seca, energia e proteína de ambas as silagens foram semelhantes entre as metodologias de coleta total de fezes e a técnica de sacos de náilon móveis quando utilizadas amostras de alimento de 8 mm. O coeficiente de digestibilidade do amido foi similar entre os métodos quando as amostras de sorgo foram moídas a 1 mm na técnica de sacos de náilon móveis. A redução da granulometria aumentou as perdas dos nutrientes dos sacos de náilon após lavagem em água. A técnica dos sacos de náilon móveis permite estimar o coeficiente de digestibilidade dos nutrientes, entretanto devem ser realizados mais estudos para avaliação da granulometria das amostras.

The ruminal degradability and intestinal digestibility of dry matter (DM), crude protein (CP) and amino acids (AA) in three total mixed rations with different CP levels were estimated using the modified in vitro three-step procedure (TSP) and mobile nylon bag (MNB) technique on growing lambs. The ruminal effective degradability of DM and CP did not respond with increasing dietary CP level. However, the intestinal digestibility of DM was significantly increased with increasing dietary CP level estimated by TSP (P < 0.05) or MNB method (P < 0.01). Intestinal digestibility coefficients of CP determined by TSP were lower than those of the MNB method. Histidine was extensively degraded by rumen microorganisms, while tyrosine was the most anti-degradable AA among the samples. The ruminal AA degradability exhibited no significant differences except for threonine, tryptophan, alanine, aspartic acid and proline for the three diets. Similarly, only a few AAs (i.e. histidine, methionine, tryptophan, aspartic acid and cysteine in TSP; histidine, tryptophan, aspartic acid and serine in MNB) had significant differences in their intestinal digestibility; in addition, values of MNB were lower than that of the TSP method, indicating that intestinal digestibility of DM seems to be overestimated in TSP, while that of CP might be overestimated in the MNB method. [ABSTRACT FROM AUTHOR]

The objectives of this study were to develop a three-step in vitro method to assess intestinal digestibility of rumen-protected products in dairy cows, and compare this method with the mobile nylon bag technique. A 3 × 4 × 3 factorial experiment was performed to determine an optimal combination of pancreatin (0.8, 1.0, and 1.2 g/30 mL), sodium cholate (0, 1.0, 2.0, and 3.0 g/30 mL), and incubation length (8, 16, 24 h) for maximizing lipid digestion of a hydrogenated fat product. Following the preliminary study, a 23 factorial experiment was conducted to investigate the effects of ruminal incubation (with or without 16 h rumen in situ incubation), gastric pH (pH = 1.0 or 2.0), and gastric acid incubation time (1 or 2 h) on digestion of the hydrogenated fat and a calcium salts of long chain fatty acids product. Once optimal culture parameters were determined, the developed in vitro method was compared with the mobile nylon bag technique. The pancreatin × sodium cholate and sodium cholate × incubation time interactions were significant in the intestinal digestibility of the hydrogenated fat product (P < 0.001), and the best case scenario was observed when the hydrogenated fat was incubated in 30 mL buffer solution containing 1.0 g pancreatin and 2.0 g sodium cholate for 24 h. A ruminal incubation × pH × incubation time interaction was detected for the intestinal digestibility of the hydrogenated fat (P = 0.002), and a ruminal incubation × pH interaction was observed for the calcium salts of fatty acids (P = 0.04). The digestion of hydrogenated fat was maximized when it was incubated in gastric pH 1.0 solution for 2 h following 16 h ruminal incubation. However, ruminal incubation had no effect on the intestinal digestibility of the calcium soap when incubated in gastric pH 1 solution (P < 0.05). The developed in vitro method had greater DM intestinal digestibility than the mobile nylon method (on average 0.78 versus 0.33), implying the mobile nylon bag method might have underestimated the DM intestinal digestibility of rumen-protected products. However, no significant difference was observed on intestinal digestibility of Met, Lys and choline in the rumen fat-protected products. Overall, the developed method could be used as an alternative approach for screening and evaluating intestinal digestibility of rumen-protected products. • A three-step in vitro method was developed to determine intestinal digestibility of rumen protected products. • The mobile nylon bag technique might underestimate the DM intestinal digestibility of rumen protected products. • The developed in vitro method can be a reliable and practical approach. [ABSTRACT FROM AUTHOR]

Abstract: The Dutch feed evaluation system for ruminants uses assumptions and regression equations to estimate the intestinal digestibility of crude protein (CP), neutral detergent fibre (NDF) and starch. These assumptions and equations are based on many different studies, obtained over a very long period. The objective of this study was to develop a unique dataset on the ruminal degradability and the postruminal digestibility of CP, NDF (aNDFom, amylase neutral detergent fibre organic matter basis) and starch in maize and grass silages, using the mobile nylon bag technique. Twenty samples of maize silage and 20 samples of grass silage were used. The samples were selected to represent a broad range in digestibility and chemical composition. Prior to the intestinal incubations, samples were incubated in the rumen for 6h (starch), 12h (CP) or 24h (aNDFom) using the rumen nylon bag technique. Residues from the rumen incubations were transferred to mobile nylon bags and inserted in the duodenum through a cannula. Half of the bags for CP and starch were collected from the ileal cannula and the remaining half of the bags from the faeces. For aNDFom, all the bags were collected from faeces. There was a large variation in the rumen degradability and the intestinal digestibility (small and/or large intestine) of CP, aNDFom and starch. The rumen degradable fractions, the intestinal digestible fractions and the total tract undigested fractions of CP, aNDFom and starch were influenced by their proportions in the maize and grass silages. The results proved the assumption of the Dutch feed evaluation system that the rumen undegraded starch is completely digested in the small intestine of dairy cows. Regression showed that the rumen degradability, the intestinal digestibility and the total tract undigested contents were influenced by the chemical composition of the maize and grass silages. [Copyright &y& Elsevier]

Intoduction. The Lotus uliginosuscv Maku legume is a forage plant with a good productive behavior. It is known because of its protein contribution and its content of condfensedtannins, which can improve the use of the protein in the intestine. Objetive. To determine the post-ruminaldigestability of the Lotus uliginosuscv Maku´s protein that can not be degraded in rumen (DPPNDR) by the use of the mobile nylon bag technique with no pre-digestion in pigs. Materials and methods. Three Holstein cows, each one with a ruminal cannula, were used, and so were three 35 kg pigs in their growth stage. The animals were kept in corrals and/or independent cages. Three regrowth ages were used, and they conformed the treatmentes T1:15, T2:30 and T3:45 reghrowth days, respectively. The data of raw protein disappearance in cows and pigs were analyzed by the use of a random blocks statistic design. Results. For the ruminal degradability variable and the total raw protein digestability, the highest value obtained was that of T1 (57,24 and 73,99 %, respectively). Nevertheless, no differences were observed in the not degradable in rumenraw protein between treatments (P>0.05). Discussion. The total quantity of raw protein degraded in T1 could be caused by the effect of the low fiber and tannins quantity in such a legume. Conclusion. TheLotus uliginosuscv Makuharvested after 15 days of regrowth is a good alternative to feed dairy cows in high tropic production systems in Colombia. [ABSTRACT FROM AUTHOR]

Abstract: A study was designed to evaluate nutrient disappearance from three Texas browse species containing condensed tannins (CT; Acacia angustissima var. hirta, Desmodium paniculatum, Smilax bona-nox, and Medicago sativa as control) using the mobile nylon bag technique. Ruminally or duodenally cannulated steers were fed a basal diet of Sorghum bicolor × S. sudanense hay. The proportion of nutrient that disappeared during rumen, pepsin/HCl, or intestinal incubation differed among plant species and nutrient evaluated (P<0.05) and did not appear to be directly related to relative CT concentrations. Dry matter (DM), inorganic matter (IM), and organic matter (OM) disappearance was greater (P<0.05) during rumen incubation than at other stages for all plant species evaluated. Of the plants containing CT, A. angustissima demonstrated the greatest overall disappearance of DM, OM, P, and crude protein (CP). A greater proportion of A. angustissima and D. paniculatum CP and P disappearance occurred in the intestinal tract compared to S. bona-nox and M. sativa. The presence of CT appears to reduce total P disappearance and shift disappearance site from the rumen to the intestines in some plant species containing CT. [Copyright &y& Elsevier]

The objective of this study was to evaluate recovery site of mobile nylon bags for measuring ileal digestibility of ruminally undegraded starch in dairy cows. Eight feed samples of untreated and treated concentrates were examined. Three lactating cows equipped with rumen fistula and duodenal and ileal cannulas were used in the experiment. The mobile nylon bags containing intact feeds or residues after a 12-h ruminal incubation were pretreated using a 2-step procedure to simulate abomasal digestion before insertion through the duodenal cannula. To assess the effect of hindgut fermentation on starch digestibility, approximately half of the bags were collected from the ileum and half from the feces. The results indicate that feed samples should be preincubated in rumen before insertion into duodenum, and that samples with relatively high fractions of rumen-undigestible starch should be collected from the ileum instead of from feces. [ABSTRACT FROM AUTHOR]

Abstract: Grass samples were grown on a clay or sandy soil, fertilised with 150 or 300kgN/ha per year, and harvested on different days during two consecutive growing seasons. The grass samples were stored frozen or ensiled after wilting to approximately 250 or 450gDM/kg. The recoveries of crude protein (CP) after passing the rumen, the intestines and the total gastro-intestinal (GI) tract in grass and grass silages were determined with the two-step mobile nylon bag technique and a two-step in vitro technique, mimicking the rumen and intestine. Mobile nylon bag experiments were performed with 9 grass samples and 18 silages of the same grasses, pre-wilted to 250 or 450gDM/kg. The in vitro experiments were performed with a series of 112 samples (54 grass and 58 grass silage samples). Both the in situ and in vitro results showed that the intestinal recoveries of CP were largely influenced by the amount of rumen-undegraded protein (RUP). A high value of RUP was compensated by an enhanced digestibility in the small and large intestine, resulting in a rather constant recovery of CP after passage through the total gastro-intestinal tract. It is suggested that residual CP after total tract passage is protein that is interwoven in the cell wall construction, cell wall bound or of microbial origin. [Copyright &y& Elsevier]