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Introduction: The total fecal collection (TFC) method is a reliable method for determining the digestibility of diets by animals. In this method, the animals are kept in a metabolic cage to collect all the feces and hence it is the most accurate method to measure the digestibility of the feed. Despite the high accuracy of this method, TFC is labor intensive and time consuming when evaluating a wide range of feed samples and requires many animals. Also, considering that being surrounded by camels is accepted for a short period of time and for camels that are fed with rations containing high amounts of energy, the animals should be confined in the stall. Another disadvantage of keeping a trapped animal is the possible effect on the animal's metabolism. These problems led to separation from the animal's natural behavior. Accurate measurement of feed intake and stool collection are difficult. Digestibility coefficients can be also measured indirectly by markers. There arevarious indigestible markers including polyethylene, chromium oxide (Cr2O3), acid detergent lignin (ADL) and acid insoluble ash (AIA) to determine the digestibility of nutrients in different parts of the digestive tract. At the end of the 19th century, lignin was used as a potential internal marker to estimate digestibility. Given that there are no specific enzymes for lignin degradation in mammals or anaerobic bacteria, different results have been reported by researchers when using ADL to estimate digestibility. Digestibility was underestimated when using AIA as a natural marker. However, it is difficult to use the AIA method for grazing animals. One of the advantages of AIA compared to other indicators is the simplicity of its analysis and does not require special equipment. This study was aimed to evaluate the apparent digestibility of nutrients in camels using AIA, ADL and TFC methods. Materials and Methods: To measure the apparent digestibility of nutrients using AIA, ADL and TFC methods, four male camels (age= 1 year, weight = 116.3 ± 9.35 kg) were used. This experiment was carried out based on a completely in a fully randomized design. The experimental period was 42 days (2 periods of 21 days) with 14 days of adaptation to the experimental diets and 7 days of data collection. Camels had free access to water and feeding was done once a day at 8 AM. In order to determine the apparent digestibility of feed nutrients, feces and feed samples were collected at the end of the 7 days of the experiment. The fecal samples weighed at 8:00 AM before feeding. The camels were kept in the stall for 5 days for adaptation. Then each camel was placed in an individual cage. In this experiment, three types of agricultural waste were used, including wheat straw, pomegranate pomace and chicken manure. Results and Discussion: The results showed a significant difference in the digestibility coefficients of dry matter, organic matter, crude fat, neutral detergent fiber and acid detergent fiber between the two methods of AIA and TFC in diets containing wheat straw or pomegranate pomace (P<0.05). There was no significant difference in the digestibility coefficients of nutrients of wheat straw diet with chicken manure between the two methods of AIA and TFC. The recovery percentage of AIA marker in diet containing 75% wheat straw + 25% poultry manure was 105.14±17.08. Conclusions: In general, it seems that due to the weak correlation between the three methods of measuring digestibility and considering the existing limitations, including the cost and many facilities, especially in large livestock, in determining digestibility with the method TFC and ADL, the AIA method can be used to determine digestibility in camels. [ABSTRACT FROM AUTHOR]

ABSTRACT Two experiments were conducted to evaluate the apparent metabolizable energy (AME), nitrogen-corrected apparent metabolizable energy (AMEn), and standardized ileal amino acid digestibility coefficient (SIDC) of extruded soybean cake (ESC) at four different extrusion temperatures: 90, 100, 110, and 120 °C. In experiment 1, 300 male broilers were randomly distributed into four treatments (600 g kg−1 reference diet + 400 g kg−1 of SBC at different extrusion temperatures) + reference diet, with six replicates of 10 birds. A metabolic assay using the total excreta collection method was performed from 14 to 23 days to determine AME and AMEn. Quadractic effect of the extrusion temperature was observed, with the maximum AMEn value estimated as 3424.99 kcal kg−1 for 105.58 °C. In experiment 2, 300 male broilers were randomly distributed into four treatments (453 g kg−1 protein free diet + 547 g kg−1 SBC at different extrusion temperatures) + protein free diet, with six replicates of 10 birds. Experimental diets were offered from 16 to 21 days, and at 21days, birds were sacrificed by cervical dislocation for collection of the ileal digesta to determine the SIDC of ESC. The best SIDC values for lysine (0.824%), methionine (0.908%), and cysteine (0.741%) were estimated at 117.72, 114.40, and 107.37 °C, respectively. The other amino acids evaluated showed a linear response, with better SIDC values with increasing extrusion temperatures. The extrusion temperatures affect metabolizable energy and amino acid digestibility of soybean cake for broilers, being important the standardization of extrusion temperature to maximize the nutritional value of soybean cake used in broiler diets.

Several studies have reported data on comparisons between two methods: the total collection of feces and the internal markers method. The aim of this study was to assess the apparent digestibility of two concentrates and to compare the apparent digestion coefficients using the total collection of feces and acid-insoluble ash (AIA) as the internal marker method. In 2009, six adult geldings aged between 3 and 11 years, with an average weight per trial of 543, 540 and 542 kg, respectively, were used to determine the apparent digestibility by means of three in vivo digestibility trials on hay, hay plus wheat bran (60 : 40) and hay plus extruded flax (80 : 20). Feces were collected over a 6-day period with a previous 14-day adaptation period. The three digestibility trials were carried out to determine the digestion coefficients of the three diets and, indirectly, of the two concentrates. The digestion coefficients of the diets were determined for the dry matter, organic matter, crude protein and gross energy, whereas the apparent digestion coefficients of the same parameters were calculated for wheat bran and extruded flax, by calculating the difference from the previous results. The data were analyzed using the Student t-test for paired samples. The digestion coefficients obtained were similar when the total collection of feces and the AIA method were used. Higher data variability, confirmed by a greater standard deviation, was observed using the AIA method to estimate the apparent digestion coefficients. It can be concluded that the use of AIA as an internal marker in digestibility trials on average leads to values similar to those obtained with the total collection of feces and can therefore be considered a less-expensive method to determine apparent digestion coefficients. Nevertheless, the total collection of feces should still be considered the best choice to determine the digestibility of some specific feedstuffs.

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.

Several studies have reported data on comparisons between two methods: the total collection of feces and the internal markers method. The aim of this study was to assess the apparent digestibility of two concentrates and to compare the apparent digestion coefficients using the total collection of feces and acid-insoluble ash (AIA) as the internal marker method. In 2009, six adult geldings aged between 3 and 11 years, with an average weight per trial of 543, 540 and 542 kg, respectively, were used to determine the apparent digestibility by means of three in vivo digestibility trials on hay, hay plus wheat bran (60 : 40) and hay plus extruded flax (80 : 20). Feces were collected over a 6-day period with a previous 14-day adaptation period. The three digestibility trials were carried out to determine the digestion coefficients of the three diets and, indirectly, of the two concentrates. The digestion coefficients of the diets were determined for the dry matter, organic matter, crude protein and gross energy, whereas the apparent digestion coefficients of the same parameters were calculated for wheat bran and extruded flax, by calculating the difference from the previous results. The data were analyzed using the Student t-test for paired samples. The digestion coefficients obtained were similar when the total collection of feces and the AIA method were used. Higher data variability, confirmed by a greater standard deviation, was observed using the AIA method to estimate the apparent digestion coefficients. It can be concluded that the use of AIA as an internal marker in digestibility trials on average leads to values similar to those obtained with the total collection of feces and can therefore be considered a less-expensive method to determine apparent digestion coefficients. Nevertheless, the total collection of feces should still be considered the best choice to determine the digestibility of some specific feedstuffs. [ABSTRACT FROM PUBLISHER]

ABSTRACT The objective of this study was to determine the digestibility coefficient (DC) of nutrients and the digestible energy (DE), and metabolizable energy (ME) values of distillers dried grains with solubles (DDGS) produced in Brazil by different methods. Eight barrows with 23.3±4.1 kg were housed in metabolic cages in a randomized block design and fed diets containing 0, 200, 400, and 600 g kg–1 of corn DDGS. We determined the digestibility of dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), mineral matter (MM), neutral detergent fiber (NDF), and gross energy (GE) by the total collection (TC) and chromium oxide marker (Cr) methods. Distillers dried grains with solubles provided the respective DM, OM, CP, EE, MM, NDF, and GE values of 910, 863, 286, 66.9, 46.8, 500 g kg–1, and 4,780 kcal kg–1. The DE and ME values of DDGS were 3,739 and 3,401 kcal kg–1 and 3,691 and 3,213 kcal kg–1 as determined by TC and Cr methods, respectively. The growing inclusion of DDGS did not affect the DE or ME values. The digestibility coefficients of DM, OM, CP, EE, MM, and NDF were 767, 765, 827, 691, 883, and 821 g kg–1, respectively, by the total collection method. The Cr underestimated the values of all variables compared with TC method. Levels up to 600 g kg–1 of the test ingredient do not influence the DE and ME of DDGS, but compromises the digestibility coefficients of DM, OM, and NDF.

ABSTRACT The objective of this study was to determine the nutritional value of glycerin for pigs using different inclusion levels of this test ingredient and the methodologies of total collection and chromium oxide marker. Eight barrows were distributed individually into metabolic cages, in a randomized-block experimental design, and fed diets containing 0, 50, 100, and 150 g kg−1 plant-derived crude glycerin. The feed digestibility methodologies of total feces and urine collection and chromium oxide marker were analyzed. Inclusion of up to 150 g kg−1 crude glycerin improved the digestibility coefficients of organic matter and energy of the diets. The collection method based on the use of chromium oxide marker underestimates the digestibility coefficient of ash and the energy values of glycerin in relation to the total collection method, but yields similar results to those obtained with the total collection method for the dry matter, organic matter, crude protein, ether extract, and neutral detergent fiber assessed.