Neutral Detergent Soluble Fibre Research Articles

EFFECTS OF LEVELS OF INSOLUBLE AND SOLUBLE FIBRE IN DIETS FOR GROWING RABBITS ON FAECAL DIGESTIBILITY, NITROGEN RECYCLING AND IN VITRO FERMENTATION

The effect of neutral detergent fibre (NDF) and neutral detergent soluble fibre (NDSF) on in vivo faecal digestibility and caecal fermentation pattern was studied in growing rabbits, in four diets formulated according to two levels of NDF, 370 (LI) and 450 (HI) g/kg, and two levels of NDSF, 150 (LS) and 180 (HS) g/kg in substitution of starch, in a 2x2 factorial structure. Twenty four New Zealand White rabbits weaned at 28 d (630 ± 80.2 g weight) were allocated to digestibility cages from 42 to 49 d of age to determine apparent faecal digestibility of each diet (n=6). Urine was collected for determination of purine derivatives (PD). Once the digestibility trial finished, rabbits were fitted with PVC neck collars for 24 h total caecotrophe collection. After one day of recovery, animals were slaughtered and caecal contents were used as inocula for 18 h in vitro gas production and caecal degradation (ivDMcD) study, using an HCl-pepsin and pancreatin pre-digested substrate. Diet digestibility was also determined by the in vitro three-step enzymatic procedure. There were no effects of the NDF x NDSF interaction for any digestibility parameter (P>0.10). Both dry matter and organic matter digestibility (DMD and OMD) decreased from 0.518 to 0.442 and from 0.526 to 0.447, respectively, with the inclusion of NDF (P<0.001), but were unaffected by the NDSF level (P>0.10). In contrast, NDF digestibility (NDFD) and ivDMcD did not respond to NDF (P>0.10) but increased from 0.156 to 0.200 and 0.141 to 0.210 with a ratio of NDSF (P<0.01). Weight of caecal contents increased with both NDF (P<0.001) and NDSF (P<0.01). However, total production of caecotrophes increased from 20.1 to 25.5 g DM/d with NDF (P<0.05), but was not affected by NDSF. The crude protein (CP) proportion in caecotrophes decreased with NDF (P<0.001) and increased with NDSF (P<0.01), and total CP recycled as caecotrophes tended (P=0.093) to be higher in HS diets, being unaffected by the dietary level of NDF. Diets rich in NDSF rendered higher gas volumes (P<0.001) than those with LS from 2 to 18 h incubation, whereas inclusion of high proportions of NDF reduced gas volume (P<0.01). Results indicate that NDF reduces faecal digestibility, whereas NDSF promotes better conditions for caecal fermentation.

Combined feeding of rabbit female and young: Partial replacement of starch with acid detergent fibre or/and neutral detergent soluble fibre at two protein levels

To evaluate the effects of the composition of weaning diets used for combined feeding both on the performance and body condition of rabbit does and on the growth and health of young rabbits, eight experimental diets were formulated according to a factorial design 2×2×2, the three factors being: i) partial replacement of starch with acid detergent fibre (ADF), ii) partial replacement of starch with neutral detergent soluble fibre (NDSF) and iii) reduction of the crude protein (CP) content from 175 to 145g kg−1 dry matter (DM). The study involved 138 rabbit does and 318 litters fed experimental diets from 17th to 28th day of lactation (weaning). Thereafter, 2371 weaned rabbits (784 in individual cages and 1587 in collective ones) continued receiving the same experimental diets until 49days of age and a commercial finishing diet until 60days of age. Replacing starch with ADF increased feed intake of does (+26±5g DM day−1, P<0.001) but, only with high CP diets, impaired their milk yield (−15±6g day−1, P<0.01) and perirenal fat thickness (PFT) change (−0.41±0.13mm, P<0.01), as well as litter weight at weaning (−154±52g, P<0.01); from weaning to 49days of age, this replacement increased feed intake (+14±2g DM day−1, P<0.001) and impaired live weight gain (−1.6±0.7g day−1, P<0.05), but reduced mortality rate (−10.2%, P<0.001). Replacing starch with NDSF reduced feed intake of does, in greater extent with high CP diets (−34±6g DM day−1, P<0.001) than with low CP diets (−19±7g DM day−1, P<0.01), as well as their milk yield (−16±4g day−1, P<0.001), with impairing PFT change only with high CP diets (−0.30±0.13mm, P<0.05); litter feed intake and weight at weaning were also negatively affected (−14.4±2.5g DM day−1, −202±38g, P<0.001); from weaning to 49days of age, this replacement reduced feed intake (−8±2g DM day−1, P<0.001), impaired live weight gain only with low CP diets (−2.3±1.0g day−1, P<0.05) and reduced mortality rate (−15.1%, P<0.001). Reducing CP content affected negatively feed intake of does (−22±5g DM day−1, P<0.001), as well as their milk yield, this impairment being more important with more starch–less ADF diets (−24±5g day-1, P<0.001) than with less starch–more ADF diets (−13±6g day−1, P<0.05), and, only with more starch–less ADF diets, PFT change (−0.36±0.13mm, P<0.01); litter feed intake was affected negatively (−20.1±2.4g DM day−1, P<0.001), as well as litter weight at weaning, in great extent when fed more starch–less ADF diets (−581±52g, P<0.001) than when fed less starch–more ADF diets (−403±54g, P<0.001); from weaning to 49days of age, this dietary change reduced feed intake (−6±2g DM day−1, P<0.001) and impaired live weight gain (−5.0±0.7g, P<0.001), but reduced mortality rate (−19.9%, P<0.001). Overall, the three dietary changes under study impaired milk yield, body condition of does and litter weight at weaning, although the negative effect of replacing starch with ADF was only observed in the high CP diets; moreover, growth during post-weaning period also decreased. However, in an Epizootic Rabbit Enteropathy context, mortality rate during this period was reduced by these three dietary changes, which effects seemed additive.

Effect of inclusion of citrus pulp in the diet of finishing swines

The aim of this work was to study the effect of inclusion of citrus pulp in the diet of finishing pigs. In the first trial, 16 Topigs barrows with 80.5±4.7 kg of initial BW were used to evaluate the digestibility of citrus pulp. Having 18.85% of neutral detergent fiber and 41.18% of neutral detergent soluble fiber, citrus pulp showed as a feasible alternative ingredient to be added in the diets of feed restricted finishing pigs. Second trial tested the use of 0, 10, 20, 30% of citrus pulp in the diets of 36-feed-restricted barrows with initial BW of 83.7±5.1 kg. A quadratic trend (P&lt;0.05) as function of citrus pulp levels was observed for daily weight gain and number of experimental days to reach 130kg BW, being the best estimated inclusion levels of citrus pulp 10.79 and 10.97%, respectively. For urea and triacylglycerol serological parameters, no effects of citrus pulp were observed (P&gt;0.05), but a quadratic trend existed on cholesterol serological content.

Effects of inclusion of neutral detergent soluble fibre sources in diets varying in forage particle size on feed intake, digestive processes, and performance of mid-lactation Holstein cows

The aim of this study was to evaluate effects of partial replacement of neutral detergent soluble fibre (NDSF) for starch in diets varying in particle size (PS) of alfalfa hay on chewing activities, ruminal fermentation, nutrient digestibility and performance in mid-lactation dairy cows. Eight multiparous Holstein cows (146 ± 6.0 d in milk; 36.7 ± 2.57 kg milk/d) were used in a replicated 4 × 4 Latin square design with four 21 d periods with the last 7 d for data collection. The experiment was a 2 × 2 factorial arrangement with 2 levels of NDSF (low = 85 g/kg or high = 130 g/kg diet dry matter) each combined with 2 PS (short = 20 mm or long = 40 mm) of alfalfa hay. Results show that forage PS alone, or in combination with NDSF inclusion, had no effect on dry matter (DM) intake. Although total chewing, eating and ruminating times were not affected by treatments, eating time per kg of neutral detergent fibre (NDF) ingested was higher in long versus short alfalfa hay-based diets ( P<0.05). Feeding long forage PS increased sorting of the diet against particles >19 mm, and in favor of those <8 mm ( P<0.05). Feeding diets high in NDSF lowered DM intake ( P<0.05), but increased apparent digestibility of all nutrients including NDF ( P<0.05) independent of forage PS. Ruminal pH and concentrations of total volatile fatty acids were unaffected by dietary treatments, however the proportion of butyrate was higher in ruminal fluid of cows fed high NDSF diets ( P<0.05). Changes in milk composition included lower milk crude protein content in high NDSF diets and higher lactose content for short hay-based diets ( P<0.05). That milk yield and milk energy output were similar in low versus high NDSF diets suggests that high NDSF-fed cows had higher energy efficiency due to lower DM intake. Results suggest that, independent of forage PS, NDSF sources can be successfully included to partly replace starchy grains in diets exceeding minimum fibre recommendations.

Carbohydrates in alfalfa-timothy mixtures predicted with near infrared reflectance spectroscopy equations developed for single species

Our objective was to evaluate the feasibility of using near infrared reflectance spectroscopy (NIRS) equations previously developed with a calibration set that included samples of both timothy and alfalfa to predict carbohydrate fractions in mixed samples of both species. Timothy and alfalfa mixed samples were prepared with the alfalfa proportion ranging from 0 to 100%, with increments of 4%. With previously developed NIRS equations based on samples of single species of timothy and alfalfa, concentrations of total ethanol soluble carbohydrates (TESC), starch, and neutral detergent soluble carbohydrates (NDSC) of the mixed samples were predicted successfully, but concentrations of organic acids (OA) and neutral detergent soluble fiber (NDSF) were unsuccessfully predicted. Adding 13 mixed samples to the initial calibration set of around 110 samples of pure timothy and alfalfa samples improved the accuracy of already successful predictions for TESC, starch, and NDSC, and resulted in a successful prediction for NDSF in timothy and alfalfa mixtures.Key words: Near infrared reflectance spectroscopy, sugars, Phleum pratense, Medicago sativa

Effect of neutral detergent soluble fibre on digestion, intestinal microbiota and performance in twenty five day old weaned rabbits

The effect of neutral detergent soluble fibre (NDSF) level on digestibility, fermentation traits, intestinal microbiota and performance was studied in weaned rabbits. A control diet (DA) containing 103 g NDSF/kg DM included dehydrated alfalfa as the main source of fibre. Another diet (B-AP) was formulated by replacing half of the dehydrated alfalfa with a mixture of beet and apple pulp resulting in 131 g NDSF/kg DM. A third diet (OH) was obtained by substituting half of the dehydrated alfalfa with a mix of oat hulls and a soybean protein concentrate and contained 79 g NDSF/kg DM. All diets contained similar levels of total fibre (NDSF + neutral detergent fibre), starch and protein (446, 208, and 199 g/kg DM, respectively). Forty-two rabbits (14/diet) weaned at 25 days were used to determine faecal digestibility from 32 to 35 days of age. This group, plus another nine rabbits/diet (23/diet), were used to determine weight of stomach and caecum and their contents, caecal fermentation traits and similarity rate (SR) of intestinal microbiota. Another 105 and 245 weaned rabbits were used to determine growth traits and mortality, respectively. From 25 to 39 days of age, rabbits were fed the experimental diets and from 39 to 60 days they were fed a commercial diet, including robenidine hydrochloride in all diets. Drinking water was supplemented with apramicine sulfate and tylosine tartrate throughout the experimental period. Faecal and energy digestibility increased linearly by 8% and NDF digestibility by 43% between extreme diets with NDSF inclusion ( P < 0.001). Weight of total gastrointestinal tract decreased linearly and quadratically with NDSF reduction ( P = 0.008 and P = 0.089, respectively). Stomach pH decreased linearly with increasing levels of NDSF ( P ≤ 0.041). Weight of caecal contents increased linearly between animals fed OH and B-AP diets ( P < 0.001). Level of inclusion of NDSF had no effect ( P ≥ 0.12) on pH, VFA concentration and VFA molar proportions in caecal contents. Treatments appeared to influence the SR of caecal microbiota but a lesser effect was observed on ileal microbiota. Post weaning feed efficiency (25–39 days) increased linearly ( P < 0.001) with NDSF inclusion by 10% between extreme diets, and by 3% in the whole fattening period ( P = 0.027). Average feed intake during the post weaning (25–39 days) and the whole fattening period increased with NDSF reduction ( P ≤ 0.079). No effect of NDSF was detected on average daily gain ( P ≥ 0.15). Mortality decreased linearly with increasing levels of NDSF in the post weaning and in the whole fattening period ( P = 0.086 and 0.016, respectively).

Near-infrared reflectance spectroscopy prediction of neutral detergent-soluble carbohydrates in timothy and alfalfa

Carbohydrates in forage crops can be divided into neutral detergent-insoluble fiber and neutral detergent-soluble carbohydrates (NDSC); the latter includes organic acids (OA), total ethanol:water-soluble carbohydrates (TESC), starch, and neutral detergent-soluble fiber (NDSF). The accurate and efficient estimation of NDSC in forage crops is essential for improving the performance of dairy cattle. In the present study, visible and near-infrared reflectance spectroscopy (NIRS) were applied to evaluate the feasibility of predicting OA, TESC, starch, NDSF, NDSC, and all related constituents used to calculate these 5 carbohydrate fractions in timothy and alfalfa. Forage samples (n=1,008) of timothy and alfalfa were taken at the first and second harvests at 2 sites in 2007; samples were dried, ground, and then scanned (400 to 2,500nm) using an NIRSystems 6500 monochromator. A calibration (n=60) and a validation (n=15) set of samples were selected for each species and then chemically analyzed. Concentrations of TESC and NDSC in timothy, as well as starch in alfalfa, were successfully predicted, but many other carbohydrate fractions were not predicted accurately when calibrations were performed using single-species sample sets. Both sets of samples were combined to form new calibration (n=120) and validation (n=30) sets of alfalfa and timothy samples. Calibration and validation statistics for the combined sets of alfalfa and timothy samples indicated that TESC, starch, and NDSC were predicted successfully, with coefficients of determination of prediction (RP2) of 0.92, 0.89, and 0.93, and a ratio of prediction to deviation (RPD) of 3.3, 3.1, and 3.6, respectively. The NDSF prediction was classified as moderately successful RP2=0.88, RPD=2.8. The NIRS prediction of OA was unsuccessful RP2=0.38, RPD=1.3. All related constituents were predicted successfully RP2>0.90, RPD>3.0 by NIRS except ethanol-insoluble residual OM, with RP2=0.75 and RPD=1.9. Our results confirm the feasibility of using NIRS to predict NDSC, its fractions, and other related constituents, except for OA and ethanol-insoluble residual OM, in timothy and alfalfa forage samples.

Chewing behaviour of Holstein steers fed diets containing different levels of non-forage fibre in a low forage diet

Sugar beet pulp (SBP) is fed to ruminants as a non-forage fibre source (NFFS) ingredient. Early work by Ronning and Bath (1962) demonstrated that SBP was similar in feeding value to barley grain for lactating dairy cattle, supporting classification of beet pulp as an energy concentrate. Sugar beet pulp contains approximately 40% neutral detergent fibre (NDF) and is unique in its high concentration of neutral detergent soluble fiber, especially pectic substances (~25% of dry matter (DM)). However, the effects of SBP when substituted with different feed sources in ration are variable that depend on chemical composition, types and physical characteristics. The time which cows spent eating and ruminating (total chewing time) is a measure of the physically effective fibre value of a feed. The objective of the present experiment was to evaluate the effect of substitution of barley grain with SBP as a NFFS on chewing activity of Holstein steers.

Fracionamento dos carboidratos pelas equações do Cornell Net Carbohydrate and Protein System de três cultivares de girassol na presença ou não de irrigação

Objetivou-se quantificar as frações de carboidratos pelas equações do Cornell Net Carbohydrate and Protein System (CNCPS) de três cultivares de girassol (Helianthus annuus L.) cultivados na presença ou não de irrigação. A utilização de uma preparação fibrosa, denominada parede celular (PC), nas equações da CNCPS, em substituição à fibra em detergente neutro (FDN) não promoveu diferenças nas frações de carboidratos B1 e C, mas influenciou as frações A e B2. Como os valores da fração B1, obtidos pelo modelo CNCPS foram menores que os teores de amido e pectina determinados em laboratório, supõe-se que a pectina e outros oligossacarídeos da parede celular, solubilizados pela solução de detergente neutro (fibra solúvel), nunca fizeram parte da fração B1, e sim da fração A. Apesar de os carboidratos da fibra solúvel apresentarem elevadas taxas de degradação, não parece adequada a caracterização da fibra solúvel na fração A. Parece mais adequado que a fibra solúvel (que inclui a pectina) seja alocada a uma fração exclusivamente sua, que pode ser a fração B2, e que seja criada uma nova fração, a B3, para os carboidratos digeríveis da parede celular. Assim, a fração B1 seria composta apenas de amido. A equação da fração C, que estima os carboidratos indigeríveis da parede celular, pode ser simplificada, relacionando a fração indigerível ao teor de lignina na matéria seca, e não à FDN isenta de cinzas e proteína, como atualmente utilizado. Esta proposta tem implicações práticas, uma vez que a fração indigerível da parede celular tem sido expressa em relação à FDN, e não na MS, com base no fato de que os efeitos inibitórios da lignina ocorrem sobre os componentes fibrosos da parede celular vegetal, e não sobre o conteúdo celular.

Prediction of Chemical Composition of Sugar Beet Pulp by near Infrared Reflectance Spectroscopy

The feasibility of near infrared (NIR) reflectance spectroscopy to estimate the chemical composition of dehydrated sugar beet pulp was examined in the present study. Seventy-three samples from different processing plants were analysed for dry matter (DM), crude protein (CP), neutral detergent fibre (NDF) and soluble (NDSF) fibre, according to the conventional chemical methods. The parameters predicted by NIR spectroscopy with the highest accuracy were DM (R2 = 0.97; SECV= 5.69 g kg−1 FM) and CP (R2 = 0.90; SECV = 3.81 g kg−1 DM) content. Furthermore, it was demonstrated that NIR technology can be used to discriminate samples of sugar beet pulp manufactured by different chemical procedures.

Neutral detergent-soluble fiber improves gut barrier function in twenty-five-day-old weaned rabbits1

The effect of neutral detergent-soluble fiber level on gut barrier function and intestinal microbiota was examined in weaned rabbits. A control diet (AH) containing 103 g of neutral detergent-soluble fiber/ kg of DM included alfalfa hay as main source of fiber. Another diet (B-AP) was formulated by replacing half of the alfalfa hay with a mixture of beet and apple pulp resulting in 131 g of soluble fiber/kg of DM. A third diet (OH) was obtained by substituting half of the alfalfa hay with a mix of oat hulls and a soybean protein concentrate and contained 79 g of soluble fiber/kg of DM. Rabbits weaned at 25 d and slaughtered at 35 d were used to determine ileal digestibility, jejunal morphology, sucrase activity, lamina propria lymphocytes, and intestinal microbiota. Suckling 35-d-old rabbits were used to assess mucosa morphology. Mortality (from weaning to 63 d of age) was also determined. Villous height of the jejunal mucosa increased with soluble fiber (P = 0.001). Rabbits fed with the greatest level of soluble fiber (BA-P diet) showed the highest villous height/ crypt depth ratio (8.14; P = 0.001), sucrase specific activity (8,671 mumol of glucose/g of protein; P = 0.019), and the greatest ileal starch digestibility (96.8%; P = 0.002). The opposite effects were observed in rabbits fed decreased levels of soluble fiber (AH and OH diets; 4.70, 5,848 mumol of glucose/g of protein, as average, respectively). The lowest ileal starch digestibility was detected for animals fed OH diet (93.2%). Suckling rabbits of the same age showed a lower villous height/crypt depth ratio (6.70) compared with the B-AP diet group, but this ratio was higher than the AH or OH diet groups. Lower levels of soluble fiber tended (P = 0.074) to increase the cellular immune response (CD8+ lymphocytes). Diet affected IL-2 production (CD25+, P = 0.029; CD5+CD25+, P = 0.057), with no clear relationship between soluble fiber and IL-2. The intestinal microbiota biodiversity was not affected by diets (P >/= 0.38). Rabbits fed the B-AP and AH diets had a reduced cecal frequency of detection compatible with Campylobacter spp. (20.3 vs. 37.8, P = 0.074), and Clostridium perfringens (4.3 vs. 17.6%, P = 0.047), compared with the OH diet group. Moreover, the mortality rates decreased from 14.4 (OH diet) to 5.1% (B-AP diet) with the increased presence of soluble fiber in the diet. In conclusion, increased levels of dietary soluble fiber improve mucosal integrity and functionality.

Fibra solúvel e amido como fontes de carboidratos para terminação de novilhos em confinamento

Avaliou-se o efeito da utilização de duas fontes de carboidratos solúveis, amido ou fibra solúvel em detergente neutro, associadas a dois níveis de FDN, sobre o desempenho de novilhos de corte em confinamento na fase de terminação. Foram confinados 24 novilhos ½ Angus x ½ Nelore, com idade inicial de 18 meses e peso de 329 ± 24 kg. As quatro dietas foram calculadas para fornecer nível de PB suficiente para ganho diário de 1,4 kg. As dietas foram constituídas de 40% de silagem de milho e 60% de concentrado (grão de milho, polpa cítrica e casca de soja), além de minerais e uréia, arranjados de forma a promover nível alto de amido associado a dois níveis de FDN (48 e 39%) ou nível alto de fibra solúvel associado aos dois níveis de FDN. Observou-se que os animais alimentados com a dieta com maior nível de polpa cítrica (45%), com baixos teores de fibra solúvel e FDN, apresentaram consumo reduzido e, conseqüentemente, baixo ganho de peso e pior conversão alimentar. Entre as dietas com maior nível de FDN, verificou-se que os animais alimentados com fibra solúvel apresentaram o melhor ganho de peso (1,435 vs 1,262 kg/dia) e a melhor conversão alimentar (7,494 vs 8,651), mas não diferiram daqueles do tratamento com amido e baixo teor de FDN. Os resultados demonstraram que é possível alterar o desempenho animal manipulando a fonte e a concentração dos carboidratos solúveis.

Response from Selection for Pectin Concentration and Indirect Response in Digestibility of Alfalfa

ABSTRACTGenetic improvement of alfalfa (Medicago sativa L.) for increased pectin concentration, estimated by neutral detergent soluble fiber (NDSF), would improve the efficiency of utilization of its high protein and digestibility by ruminants. The objectives of this study were to: (i) estimate the realized direct response from one cycle of phenotypic selection for NDSF concentration; (ii) evaluate association of NDSF concentration with other forage quality traits, and; (iii) determine the impact of selection for NDSF concentration on in vitro dry matter digestibility (IVDMD) of alfalfa. Selection for NDSF was applied to five alfalfa populations from 1996 to 2000 and synthetic generation two seed was produced. Progress from selection for NDSF concentration was evaluated in plot trials for 2 or 3 yr at two locations near Ithaca, NY. Populations divergently selected for NDSF were 1.62 to 5.15 g kg−1 of dry matter (DM) higher and 2.26 to 4.20 g kg−1 DM lower, respectively, than their respective base populations. Neutral detergent soluble fiber concentration was negatively correlated with total cell wall concentration (CW), and proportions of neutral detergent fiber (NDF), cellulose, and lignin in the CW. A positive correlation existed between NDSF concentration and crude protein (CP) concentration and IVDMD. Populations bred for higher or lower NDSF concentration had 0.20 to 8.82 g kg−1 DM higher IVDMD and 0.63 to 15.06 g kg−1 DM lower IVDMD than their respective base populations. Selection for NDSF concentration and indirectly for CP, total CW concentration and composition, and IVDMD of alfalfa forage was successful.

Sistema laboratorial de fracionamento de carboidratos de energéticos

Laboratorial system of carbohydrate fractions of energetic concentrate. The aim of this work was to evaluate a laboratorial system of carbohydrate fractions to identify and quantify the fractions that compose this nutrient. The following fractions were determined: simple sugars (SS) using the colorimetric phenol-sulfuric method; digestible starch (DS) and resistant starch (RS) by enzymatic digestions; total fiber (TF) using the enzymic-gravimetric method; neutral detergent fiber (NDF) and soluble fiber (SF) estimated by difference TF - NDF, in grains of corn and sorghum, citric pulp, wheat middlings, wheat mills and rice bran. The coefficient of variation for fractions SS, DS, RS, TF and NDF varied from 4.81 to 19.17%; 4.58 to 15.03%; 2.42 to 9.91%; 1.23 to 8.23% and 1.16 to 8.42%; respectively. A good repeatability of the method used was observed. The fraction identified the main groups of carbohydrates composed on the food and it can be a reference to future works.

Estimativa da degradabilidade ruminal de alimentos utilizando a técnica de produção de gás em bovinos, ovinos e caprinos

Conduziu-se este trabalho com o objetivo de validar a técnica de produção de gás na avaliação de alimentos concentrados e volumosos e as possíveis diferenças entre bovinos, ovinos e caprinos quanto à degradação desses alimentos. O experimento foi conduzido no Laboratório de Pesquisa Animal do Departamento de Zootecnia da UFLA. O líquido ruminal (inóculo) foi originado de três vacas Holandesas, três ovelhas e três cabras sem raça definida, fistuladas no rúmen. Foram avaliadas as frações solúvel em detergente neutro (SDN) e fibra em detergente neutro(FDN) de fubá de milho, farelo de soja, farelo de algodão, caroço de algodão, farelo de trigo, polpa cítrica, feno de alfafa, feno de coast cross, silagem de milho e silagem de capim. As leituras do volume cumulativo de gás foram feitas 1, 2, 3, 4, 5, 6, 12, 18, 24, 30, 36, 48, 60 e 72 horas após a incubação. Não houve diferença (P&gt;0,05) entre as espécies, para nenhuma das variáveis estudadas. A fração SDN apresentou maior produção de gás e taxa de degradação em relação a FDN. A técnica de produção de gás permitiu estimar as taxas de digestão das frações insolúveis e, principalmente, das frações solúveis dos carboidratos totais.

Effects of carbohydrates from citrus pulp and hominy feed on microbial fermentation in continuous culture.

Eight dual-flow continuous-culture fermenters were used to evaluate the effect of neutral detergent-soluble carbohydrates (NDSC) on fermentation by ruminal microorganisms. Citrus pulp and hominy feed were added to a basal diet as sources of NDSC, with citrus pulp providing neutral detergent-soluble fiber (NDSF) in the form of pectic substances and with hominy feed in the form of starch. The basal diet contained 26.7% corn silage, 6.0% alfalfa hay and 3.8% cottonseed hulls on a DM basis. The dried citrus pulp diet contained on a DM basis 17.2% CP, 34.7% NDF, 33.7% NDSC, and 14.4% NDSF, whereas the hominy feed diet contained 17.9% CP, 33.2% NDF, 35.9% NDSC, and 8.8% NDSF. Organic matter, DM, and NDF and ADF digestion were not affected by source of carbohydrate. Ammonia N concentration was greater (P < 0.05) for the hominy feed diet (14.2 mg/100 mL) than for the dried citrus pulp diet (9.3 mg/100 mL). Total N, nonammonia N, microbial N, and dietary N flows were not affected by treatments; however, the efficiency of microbial protein synthesis was greater (P = 0.055) for the dried citrus pulp diet than for the hominy feed diet (30.6 vs 27.8 g of bacterial N/kg of OM truly digested). Results from this experiment indicate that NDSF from citrus pulp can provide similar sources of energy compared with starch from hominy feed to support ruminal microbial growth.

Performance of Dairy Cattle Fed Citrus Pulp or Corn Products as Sources of Neutral Detergent-Soluble Carbohydrates

The effects of modifying the dietary profile of neutral detergent-soluble carbohydrates (NDSC) on milk production and rumen fermentation were determined. Corn silage and alfalfa hay-based diets were formulated to contain 40% calculated NDSC supplied primarily by dried citrus pulp as a source of neutral detergent-soluble fiber (NDSF), or corn products as sources of starch. Diets were compared within cow with reversal experiments with two periods. In experiment 1, 11 multiparous Holstein cows including three ruminally cannulated animals were individually fed diets containing 23.6% citrus pulp (diet CPD) or 25.3% corn hominy (diet HD) on a dry matter basis. In experiment 2, 184 animals fed as two groups received diets containing 20.5% citrus pulp (diet CPD) or 19.5% cornmeal (diet CMD). Diets CPD provided more dietary NDSF and HD and CMD more starch. In experiment 1, cows fed HD had a greater milk protein percentage (+0.12%), and tended to yield more milk protein (0.08kg/d) than cows fed CPD. Although ruminal H+ concentrations did not differ between diets, diet × time postfeeding interactions were significant. Ruminal organic acid concentrations did not differ between diets. In experiment 2, cows fed CMD yielded more milk (3.9kg/d), 3.5% fat- and protein-corrected milk (2.6kg/d), fat (0.05kg/d), and protein (0.08kg/d), whereas cows fed CPD produced greater concentrations of fat (+0.18%), and milk urea nitrogen (0.76mg/dl). Modifying the proportions of NDSC in the diet can alter milk production and composition, the pattern of ruminal fermentation, and N utilization in dairy cows.

A method for partitioning neutral detergent-soluble carbohydrates

A method was developed to fractionate the neutral detergent-soluble carbohydrates (NDSC) in feedstuffs. Differential solubilities of carbohydrates in 80:20 (v/v) ethanol/water were used to partition NDSC into organic acids (OA) and mono- and oligosaccharides soluble in ethanol/water from starch and neutral detergent-soluble fibre (NDSF) which are insoluble. Mono- and oligosaccharides (total ethanol/water-soluble carbohydrate) were measured on the ethanol/water extract, and starch was measured on the ethanol/water-insoluble residue. The OA and NDSF, the two most compositionally diverse NDSC fractions, were estimated by difference. The method allows partitioning of the NDSC on a nutritionally relevant basis into (1) organic acids, (2) total ethanol/water-soluble carbohydrate, (3) starch and (4) neutral detergent-soluble fibre. The methods involved in this fractionation are relatively simple or are commonly used. © 1999 Society of Chemical Industry

A method for partitioning neutral detergent‐soluble carbohydrates

A method was developed to fractionate the neutral detergent-soluble carbohydrates (NDSC) in feedstuffs. Differential solubilities of carbohydrates in 80:20 (v/v) ethanol/water were used to partition NDSC into organic acids (OA) and mono- and oligosaccharides soluble in ethanol/water from starch and neutral detergent-soluble fibre (NDSF) which are insoluble. Mono- and oligosaccharides (total ethanol/water-soluble carbohydrate) were measured on the ethanol/water extract, and starch was measured on the ethanol/water-insoluble residue. The OA and NDSF, the two most compositionally diverse NDSC fractions, were estimated by difference. The method allows partitioning of the NDSC on a nutritionally relevant basis into (1) organic acids, (2) total ethanol/water-soluble carbohydrate, (3) starch and (4) neutral detergent-soluble fibre. The methods involved in this fractionation are relatively simple or are commonly used. © 1999 Society of Chemical Industry

Near Infrared Reflectance Spectroscopy Prediction and Heritability of Neutral Detergent‐Soluble Fiber in Alfalfa

Increasing neutral detergent‐soluble fiber (NDSF) concentration has been considered a strategy for breeding alfalfa (Medicago sativa L.) with improved quality. Pectin is the main component of NDSF and is highly digestible, but the assay for NDSF is time‐consuming. The objectives were (i) to determine the potential use of near infrared reflectance spectroscopy (NIRS) to predict NDSF concentration in alfalfa and (ii) to estimate NDSF heritability and gain from selection. Herbage was sampled five times across 2 yr from two populations of half‐sib (HS) progeny tested at Ithaca, NY. Calibration equations were developed by multiple linear regression of laboratory values of NDSF on NIRS spectra. Samples from one harvest were assayed twice to compare extraction methods. Means of NDSF from 90‐ and 80%‐ethanol extractions were 213.1 ± 7.21 and 179.5 ± 5.89 g kg−1, respectively. Assay standard deviations were low for both ethanol concentrations. Because a better calibration equation was obtained with the 80%‐ethanol assay, all remaining samples were assayed by that technique. Standard errors of calibration were small, ranging from 4.71 to 7.54 g kg−1. Coefficients of multiple determination (R2) ranged from 0.72 to 0.97. Most heritability estimates for NDSF were significantly greater than zero, ranging from −0.03 ± 0.20 to 0.56 ± 0.17 and averaging 0.41. Expected gain from selection of parents based on HS progeny ranged from 4.6 to 19.0 g kg−1 and averaged 10.3 g kg−1. Selecting parents with higher NDSF concentrations predicted by NIRS evaluations of HS progenies may improve forage quality of alfalfa.