True Organic Matter Digestibility Research Articles

PSV-26 Effect of addition of Ascophyllum nodosum and Asparagopsis taxiformis, alone or in combination, to an herbage-based diet on in vitro fermentation in continuous culture

Abstract This study investigated the effect of individual or simultaneous addition of two macroalgae species on in vitro fermentation in continuous culture. Four single-flow continuous culture fermentors were fed an orchardgrass herbage-based (orchardgrass; Dactylis glomerata L.) basal diet and randomly assigned one of four treatments: 1) control (CON), no macroalgae addition; 2) Ascophyllum nodosum dosed at 2.5% dry matter (DM; ASC); 3) Asparagopsis taxiformis dosed at 0.5% DM (ATX); and 4) A. nodosum (2.5% DM) + A. taxiformis (0.5% DM) dosed simultaneously (AS+AT). Four experimental periods were conducted in a randomized block design with 7 d of treatment adaptation and 3 d of sample collection. Fermentors were fed 82 g of DM per day in 4 equal feedings. In the last 3 d of each experimental period, daily samples of total effluent were taken for analyses of ammonia N and volatile fatty acids (VFA). Effluent was composited by fermentor and analyzed for DM, ash, neutral and acid detergent fiber, and crude protein. Purine concentrations of effluent and bacterial isolates were determined to estimate partitioning of N flow into feed, bacterial, and ammonia N fractions. Methane (CH4) emissions were measured in each fermentor every 15 min using a Fourier transform infrared gas analyzer, and pH was recorded every 2 min. Data were analyzed using the MIXED procedure of SAS v 9.4 with pre-planned contrasts comparing each individual macroalgae to CON (CON vs. ASC and CON vs. ATX) and comparing A. taxiformis with and without simultaneous addition of A. nodosum (ATX vs. AS+AT). Significance was declared at P ≤ 0.05 and tendencies at 0.05 < P ≤ 0.10. Nutrient digestibilities, CH4 emissions, pH, and N metabolism variables were not affected (P > 0.10) in ASC compared with CON, but total VFA concentration increased (P < 0.05) by 10%. Contrarily, the ATX diet tended (P = 0.61) to have reduced true organic matter digestibility, reduced (P < 0.05) total VFA concentration by 11%, and reduced (P < 0.05) CH4 production by 99.9% versus CON. Simultaneous the combination of microalgae (AS+AT) did not further reduce (P > 0.10) nutrient digestibility or total VFA concentration compared with ATX, and did not change (P > 0.10) the degree of CH4 inhibition. However, A. nodosum did not mitigate (P > 0.10) any of the negative effects on fermentation associated with A. taxiformis, as nutrient digestibilities and N metabolism variables in AS+AT were also not different (P > 0.10) from ATX. While the macroalgae species, A. nodosum and A. taxiformis, led to different fermentation patterns when added individually to continuous culture fermentors, no negative or positive interactions were observed from their simultaneous addition.

Comparison of forages’ digestion levels for different in vitro digestion techniques in horses

Forages are widely used in horse diets. Different in vitro techniques are being tried to determine the fermentation levels of forages in the horse digestive tract. This study aimed to evaluate the digestion levels of four dry forages commonly used in horse nutrition: alfalfa herbage, meadow hay, wheat straw, and Italian ryegrass. In vitro total digestion (TDT), in vitro Sunvold-large intestine digestion (SDT) and in vitro Menke-large intestine digestion (MDT) techniques were compared. The study determined in vitro true dry matter digestion (T-DMD), in vitro true organic matter digestion (T-OMD) and in vitro true neutral detergent fibre digestion (T-NDFD). Additionally, concentrations of straight short-chain fatty acids (SCFAs; acetic acid - AA, propionic acid , butyric acid, and valeric acid ) and branched short-chain fatty acids (BSCFA) were assessed. The highest in vitro T-DMD, T-OMD and T-NDFD values were determined by the in vitro TDT for the four forages (p<0.05). In vitro T-DMD and T-OMD values of alfalfa herbage were higher than those of Italian ryegrass, meadow hay and wheat straw in the in vitro TDT (p<0.001). In addition, in vitro T-DMD and T-OMD values of alfalfa herbage in the in vitro SDT were higher than those of meadow hay and wheat straw (p<0.001). In the in vitro TDT, the molarity of AA, total SCFA and BSCFA in the digestion fluid of alfalfa herbage was higher than those of other forages (p<0.05). The in vitro total enzymatic+fermentative digestion technique for horse forages revealed higher values than the in vitro fermentative digestion techniques. In general, the higher the non-structural carbohydrate and crude protein contents in the forage, the higher the results of the in vitro TDT compared to the other techniques.

The effect of seaweed formulations on in vitro fermentation, nutrient utilization and growth performance in crossbred calves

The aim of this research was to study the effect of seaweed formulations on in vitro rumen fermentation, nutrient utilization and growth performance of crossbred calves. The study included 18 male crossbred calves of 130±7.56 kg body weight, divided into 3 groups of 6 each following a completely randomized design. Calves in the control (T0) were fed a standard diet, while treatment groups T1 and T2 were supplemented with AF-KWP or AFRD-5 at the rate of 4% of concentrate mixture, with 1% calcium carbonate and 1% dicalcium phosphate replacing the mineral mixture, and common salt offered in T0 . The experiment was conducted for a period of 120 days. At the end of the experiment, a metabolism trial was conducted to study the nutrient utilization. In vitro total gas and methane production was significantly (P&lt;0.05) lower in the seaweed supplemented groups. A significant difference (P&lt;0.05) was also observed in the retention of calcium and phosphorus between the different groups. A non-significant difference was observed in nutrient digestibility, dry matter intake, total gain in body weight, average daily gain and feed conversion ratio between the three treatment groups. It might be concluded that seaweed formulations significantly reduced in vitro total gas and methane production without affecting true dry matter digestibility and true organic matter digestibility. Moreover, seaweed formulation supplementation did not affect the growth performance and nutrient utilization in the crossbred calves.

Seasonal nutritive value and in vitro fermentation kinetics of foliage of some multipurpose shrub species in northeastern Mexico

This study aimed to determine seasonal chemical composition, metabolizable energy (ME) concentration, in vitro gas production patterns, in vitro organic matter digestibility (IVOMD) and in vitro true organic matter digestibility (IVTOMD) of foliage from 5 native shrub species (Celtis pallida, Croton suaveolens, Forestiera angustifolia, Guaiacum angustifolium and Parkinsonia aculeata) growing in semi-arid areas of northeastern Mexico between July 2018 and June 2019 at 2 research sites. Crude protein (CP) concentrations (&gt;13.2% DM) found in leaf material should meet or exceed the requirements for maintenance of small ruminants; C. pallida provided the highest CP% (20.8‒29.3%). While CP% varied with season and site, species had a greater effect than either of those factors overall. ME concentrations ranged between 1.2 and 2.0 Mcal/kg DM. Neutral detergent fiber and acid detergent fiber concentrations ranged from 29.8 to 51.7% DM and 9.8 to 33.0% DM, respectively. Data obtained for IVOMD (34.5‒58.8%) and IVTOMD (64.1‒88.7%) demonstrate the high nutritive potential of leaf of browse species under study, especially C. pallida, as useful feed supplements for small ruminants in the semi-arid region of northeastern Mexico. Further studies could examine DM yields of browse from the various species, acceptance by small ruminants and their sustainability under regular defoliation under grazing.

English

The purpose of this study was to determine the feed values of some legume forage plants growing in a natural environment. The plant materials used in the study were as follows: Alfalfa (Medicago sativa), varigated alfalfa (Medicago varia), bird vetch (Vicia cracca), mountain vetch (Vicia alpestris), mountain clover (Trifolium montanum), kura clover (Trifolium ambiguum), three-headed clover (Trifolium trichocephalum), purple crownvetch (Coronilla varia), and bird’s foot trefoil (Lotus corniculatus). The feeds were examined in terms of nutrient content, relative feed value, true dry matter digestibility, true organic matter digestibility, true neutral detergent fiber digestibility, and relative feed quality. The legume forage plants were found to be significantly different from each other in terms of nutrient contents (P&lt;0.05). The mountain clover was found to have the highest contents of crude protein and crude fat among the legume forage plants examined in this study, while the alfalfa was found to have more contents of dry matter and NDF than the other legume forage plants. On the other hand, the dry matter intake was found to be the highest in the three-headed clover, the dry matter digestibility and relative feed value were found to be the highest in the purple crownvetch, and the relative feed quality was found to be the highest in the mountain vetch. The nutrient contents, relative feed values, and relative feed quality values of the forage plants showed that they could be used in animal feeding.

Determining the nutrient content, energy, and in vitro true digestibility of some grass forage plants

The purpose of this study was to compare the chemical composition, metabolizable energy, net energy lactation, total digestible nutrient, in vitro digestion parameters, and relative feed quality of some grass forage plants growing naturally in the meadows and pastures of Erzurum province in Turkey. Orchardgrass (Dactylis glomerata), Variegated brome (Bromus variegatus), and Intermediate wheatgrass (Agropyron intermedium) were used as the research material. In this study, the metabolizable energy (ME) and net energy lactation (NEL) contents of the green grass crops forage plants were determined by in vitro gas production method, and their digestibility parameters and relative feed quality (RFQ) by the neutral detergent fiber (NDF) procedure using an Ankom Daisy incubator. As a result of the study, the differences between the forage plants were found to be statistically significant in terms of chemical composition, metabolizable energy, net energy lactation, true organic matter digestibility (TOMD) and RFQ (P&lt;0.05). While the green intermediate wheatgrass was found to have the highest crude protein (CP) (19.56%), crude fat (CF) (3.06%), dry matter (DM) (9.14%), ME (8.82%), NEL (5.42%), and TOMD (97.75%); the green variegated brome was found to have the highest RFQ (149.79). The green orchardgrass was found to have the highest contents of neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) with 66.23%, 34.14, and 8.52%, respectively. In conclusion, the green grass forage plants examined in this study can be used to eliminate the quality roughage deficit.

In vitro and in vivo evaluation of some tree leaves as forage sources in the diet of Baluchi male lambs

This study aimed to evaluate the potential use of some tree leaves including almond (Prunus amygdalus L.), pomegranate (Punica granatum L.), apple (Malus domestica Borkh.), pistachio (Pistacia vera L.), and walnut (Juglans regia L.) compared to whole plant alfalfa (Medicago sativa L.) in sheep feeding through in vitro experiments in order to screening of the resources and then selecting the most suitable candidate resource for in vivo experiment. Chemical and mineral composition, in vitro gas production, and fermentation parameters of leaves were also determined. The results indicated that the crude protein (CP) ranged from 12.12 % for almond leaves (AL) to 16.77 % for alfalfa, on dry matter (DM) basis. The highest and lowest neutral detergent fiber (NDF) content was observed in alfalfa (48.50 %) and pomegranate leaves (26.45 %), respectively (P < 0.0001). The range of metabolisable energy (ME) differs from 6.76 for pomegranate leaves to 10.50 MJ/kg DM for AL. Alfalfa and AL exhibited the lowest (9.53 g kg DM) and the highest calcium (44.15 g/kg DM) concentration, respectively (P < 0.0001). The highest true organic matter (TOMD) and dry matter digestibility (TDMD) (88.44 and 87.88 %, respectively) was also obtained in AL (P < 0.0001). It was found that AL had the highest potential gas production, and total volatile fatty acids (VFA) values of 61.05 ml/200 mg DM, and 48.33 mmol/L, respectively (P < 0.0001). In in vivo experiment, the effects of partial substitution of dietary forage with AL at 0, 5.8, 11.5, and 23 % of diet DM on growth performance, nutrient digestibility, ruminal fermentation, and blood metabolites were investigated using thirty-two Baluchi male lambs [28 ± 1.5 kg body weight (BW)] in a completely randomized design for 90 days. Compared to the control group, dry matter intake (DMI, P = 0.02), average daily gain (ADG, P = 0.05), DM (P = 0.0004), organic matter (OM, P = 0.003) and NDF digestibility (P = 0.0005), total VFA (P = 0.02), and plasma total antioxidant capacity (TAC, P = 0.0005) increased when high level of almond (HAL) was added to the diet. Overall, it is revealed that AL had a high nutritional value and could be used up to 23 % of diet DM in the diet of Baluchi male lambs as an inexpensive alternative forage without negative effects on performance and blood metabolites.

Nutrient contents and in vitro digestibility of different parts of corn plant

AbstractThe objective of this study was to assess the nutrient contents and in vitro true digestibility (IVTD) of parts of the corn plant. The corn used in the study was P2088, a variety that is grown widely in Turkey. It had matured and was harvested 140 days after planting. Four replicate plants were separated into nine parts, namely lower stalk, central stalk, upper stalk, corn ear stalk, corn ear shuck, kernels, corn cob, leaf, tassel, plus the entire plant. The samples were dried and ground for analysis. Nutritional values were determined in the laboratory and in vitro digestibility was assessed. Significant differences in nutrient content were observed among parts of the corn plant. The highest crude protein (CP) content was found in the leaf (12.41%), followed by the grain (12.37%). Dry matter (DM) varied from 91.25% to 96.07%. The highest ether extract (EE) was in the grain (2.84%), and the upper stalk contained the least EE (0.29%). The parts also differed in their contents of crude cellulose (CS) and crude ash (CA) (P &lt;0.001). Most organic matter (OM) was found in the corn cup (94.27%). The highest in vitro dry matter digestibility (IVDMD) was in the kernels (79.06%) and the lowest was in the lower stalk (38.13%). In terms of in vitro true organic matter digestibility (OMD) values of the corn plant and its 9 parts, the highest values were found in the kernels and the lowest in the lower stalk.Keywords: crude nutrients, in vitro true digestibility, parts of corn plant

Comparison of microbial fermentation data from dual-flow continuous culture system and omasal sampling technique: A meta-analytical approach

Although the omasal sampling technique (OST) has been successfully used to estimate ruminal fermentation and nutrient flow, alternatives to invasive animal trials should be pursued and evaluated. The objective of this study was to evaluate carbohydrate and N metabolisms using a meta-analytical approach to compare 2 methods: dual-flow continuous culture system (DFCCS) and OST. To be included, studies needed to report diet chemical composition and report at least 1 of the dependent variables of interest. A total of 155 articles were included, in which 97 used the DFCCS and 58 used the OST. The independent variables used were dietary nonfiber carbohydrate concentration, neutral detergent fiber (NDF) degradability, true crude protein (CP) degradability, and efficiency of microbial protein synthesis (EMPS). In addition, 12 dependent variables were used. Statistical analyses were performed using the Mixed procedure of SAS (SAS Institute Inc., Cary, NC). A random coefficients model was used considering study as a random effect and including the possibility of covariance between the slope and the intercept. The effect of method (DFCCS or OST) was included and tested in the estimates of the intercept, linear, and quadratic effects of the independent variable. There was no method effect when NDF degradability was regressed with total volatile fatty acids concentration, true CP degradability, and EMPS. Molar proportions of acetate and propionate were quadratically associated with NDF degradability. When NDF degradability was regressed with acetate and propionate there was a method effect, differing only in the intercept (β0) estimate. True organic matter digestibility, bacterial N/total N, efficiency of N utilization, total volatile fatty acid concentration, and molar proportion of butyrate linearly increased as dietary nonfiber carbohydrate concentration increased, and none of these variables were affected by method. Concentration of ammonia N had a linear and positive association with true CP degradability. This was the only variable that had a method effect when regressed with true CP degradability, differing only in the estimate of the intercept (β0). As EMPS increased, efficiency of N utilization also increased, and it was affected by method. Overall, the majority of DFCCS responses were similar to OST. When a method effect was observed, it was mainly on the estimate of the intercept, demonstrating that the magnitude of these responses was different. However, the relationships between independent and dependent variables were similar across methods.

Farklı Seviyelerde Pamuk Tohumu Küspesi ve Arpa İlave Edilerek Hazırlanan Mısır Silajlarının Kalitelerinin Belirlenmesi

Bu çalışmada, besi sığırlarının besin madde ihtiyaçlarını karşılamak için mısır hasılına arpa ve farklı seviyelerde pamuk tohumu küspesi (PTK) ilavesinin silaj besin madde bileşimi, fermentasyon özellikleri ve invitro rumen parametreleri üzerine etkisi araştırılmıştır. Araştırmada mısır hasılı (MH) (kontrol), mısır hasılına %4 arpa ve %2, 4, 6, 8 PTK ilave edilerek toplam 5 grup oluşturulmuştur. Her grupta 5’er tekerrür olmak üzere hazırlanan 25 adet silaj örneği, 1.5 L’lik cam kavanozlara sıkıştırılmış ve kavanozlar 60 gün sonra açılmıştır. Silaj örneklerinin kuru madde (KM), ham kül (HK), ham protein (HP), asit deterjanda çüzünmeyen lif (ADF), nötral deterjanda çözünmeyen lif (NDF), invitro organik madde sindirimi (İVOMS), metabolik enerji (ME), silaj pH (SpH), laktik asit (SLA), propiyonik asit (SPA), asetik asit (SAA), bütirik asit (SBA) ve amonyak azotu (SNH3-N) analizleri yapılmıştır. Ayrıca invitro rumen asteik asit (RAA), propiyonik asit (RPA), bütirik asit (RBA) amonyak azotu (RNH3-N), pH (RpH), invitro gerçek sidirilebilir organik madde (İVGSOM) ve invitro mikrobiyal protein üretimi (İVMPÜ) belirlenmiştir. Mısır hasılındaki PTK seviyesinin artışına paralel olarak silaj örneklerinin KM, HK, HP, ADF, SpH, SNH3-N, İVMPÜ, RNH3-N, RpH düzeyleri artarken (P

In vitro evaluation of utilisable crude protein and methane production for a diet in which grass silage was replaced by different levels and fractions of extracted seaweed proteins

Utilisable crude protein (uCP), methane (CH4) production and other fermentation parameters were analysed in vitro for a diet in which grass silage was replaced by different levels of seaweed protein fractions prepared from three seaweed species: Saccharina latissima, Alaria esculenta and Palmaria palmata. Ten fractions from these three species in which the protein content had been increased and the salt content reduced by simple processing were tested, with inclusion levels in the diet based on the nitrogen content of the fractions. Following an extraction procedure, four fractions from Saccharina latissima, three from Alaria esculenta and one from Palmaria palmata, were incrementally included in the diet by replacing high quality silage with approximately 0, 0.15, 0.30 and 0.45 g/g DM, while two high-protein fractions of Palmaria palmata were tested at replacement levels of 0, 0.075, 0.15 and 0.225 g/g DM. To estimate fermentation parameters, 500 mg of each diet were incubated in bottles with 60 mL buffered rumen fluid. Estimated uCP increased linearly with increasing replacement rate of grass silage with seaweed protein fractions (from 158 g/kg DM to 206 g/kg DM on average for all fractions). Increasing protein fraction from the brown seaweed Saccharina latissima in the diet significantly increased true organic matter digestibility (OMD) (from on average 0.786 to 0.821). Organic matter digestibility decreased with increasing level of Alaria esculenta fractions (from on average 0.785 to 0.733), which also gave a linear decrease in CH4 production (from on average 45.3 to 38.5 mL/g organic matter). As a result of decreased CH4 production and OMD, total volatile fatty acid concentration decreased with increasing level of Alaria esculenta fractions (from on average 69.5 to 63.0 mmol/L). Thus, positive and species-specific effects of seaweed on estimated uCP and fermentation parameters were observed in vitro when protein fractions remaining after an extraction procedure on seaweed partly replaced grass silage in the feed ration.

Essential oil and monensin affect ruminal fermentation and the protozoal population in continuous culture

The interaction of monensin and essential oil was hypothesized to suppress protozoa and methane production while maintaining normal rumen function. The objective of this study was to determine the effects of feeding monensin (MON) and CinnaGar (CIN, a commercial blend of cinnamaldehyde and garlic oil; Provimi North America, Brookville, OH) on ruminal fermentation characteristics. Continuous culture fermentors (n = 4) were maintained in 4 experimental periods in a 4 × 4 Latin square design. Four dietary treatments were arranged in a 2 × 2 factorial: (1) control diet, 37 g/d of dry matter (40 g/d at ∼92.5% dry matter) of a 50:50 forage:concentrate diet containing no additive; (2) MON at 11 g/909 kg of dry matter; (3) CIN at 0.0043% of dry matter; and (4) a combination of MON and CIN at the levels in (2) and (3). Treatment had no effects on protozoal populations, concentration of NH3N, total N flow of effluent, production of total volatile fatty acids, or flows of conjugated linoleic acid and total C18 fatty acids. The MON decreased acetate:propionate ratio and biohydrogenation of both total C18 and 18:1 cis-9 but increased protozoal generation time, concentration of peptide, and flow of 18:1 trans-11. The MON tended to decrease protozoal counts in effluent and flow of 18:0 but tended to increase propionate production. The CIN decreased true organic matter digestibility and protozoal N flow of effluent but increased nonammonia, nonmicrobial N flow. The CIN tended to decrease protozoal counts, microbial N flow, and neutral detergent fiber digestibility but tended to increase biohydrogenation of total C18, 18:2, and 18:3. The CIN tended to increase isovalerate production. The MON and CIN tended to interact for increased methane production and bacterial N flow. A second experiment was conducted to determine the effects of MON and CIN on protozoal nitrogen and cell volume in vitro. Four treatments included (1) control (feed only), (2) feed + 0.0043% dry matter CIN, (3) feed + 2.82 μM MON, and (4) feed + CIN + MON at the same levels as in (2) and (3). With no interactions, MON addition decreased percentage of protozoa that were motile and tended to decrease cell volume at 6 h. The CIN did not affect cell count or other indicators of motility or volume at either 3 or 6 h. Under the conditions of our study, we did not detect an additive response for MON and CIN to decrease protozoal counts or methane production. A 3-dimensional method is suggested to better estimate protozoal cell volume.

Effect of feeding warm-season annuals with orchardgrass on ruminal fermentation and methane output in continuous culture

A 4-unit, dual-flow continuous culture fermentor system was used to assess nutrient digestibility, volatile fatty acids (VFA) production, bacterial protein synthesis, and methane (CH4) output of warm-season annual grasses. Treatments were randomly assigned to fermentors in a 4 × 4 Latin square design using 7 d for adaptation to treatment and 3 d for sample collection. Treatments were (1) 100% orchardgrass (Dactylis glomerata L.; ORD); (2) 50% orchardgrass + 50% Japanese millet [Echinochloa esculenta (A. Braun) H. Scholz; MIL]; (3) 50% orchardgrass + 50% brown midrib sorghum × sudangrass (Sorghum bicolor L. Moench × S. bicolor var. sudanense; SSG]; or (4) 50% orchardgrass + 25% millet + 25% sorghum × sudangrass (MIX). Fermentors were fed 60 g of dry matter (DM)/d in equal portions of herbage 4 times daily (0730, 1030, 1400, and 1900 h). To replicate a typical 12-h pasture rotation, fermentors were fed the orchardgrass at 0730 and 1030 h and the individual treatment herbage (orchardgrass, Japanese millet, sorghum × sudangrass, or 50:50 Japanese millet and sorghum × sudangrass) at 1400 and 1900 h. Gas samples for CH4 analysis were collected 6 times daily at 0725, 0900, 1000, 1355, 1530, and 1630 h. Fermentor pH was determined at the time of feeding, and fermentor effluent samples for NH3-N and VFA analyses were taken daily at 1030 h on d 8, 9, and 10. Samples were also analyzed for DM, organic matter (OM), crude protein, and fiber fractions to determine nutrient digestibilities. Bacterial efficiency was estimated by dividing bacterial N by truly digested OM. True DM and OM digestibilities and pH were not different among treatments. Apparent OM digestibility was greater in ORD than in MIL and SSG. The concentration of propionate was greater in ORD than in SSG and MIX, and that of butyrate was greatest in ORD and MIL. Methane output was greatest in MIL, intermediate in ORD, and lowest in SSG and MIX. Nitrogen intake did not differ across treatments, whereas bacterial N efficiency per kilogram of truly digestible OM was greatest in MIL, intermediate in SSG and MIX, and lowest in ORD. True crude protein digestibility was greater in ORD versus MIL, and ORD had lower total N, non-NH3-N, bacterial N, and dietary N in effluent flows than MIL. Overall, we detected little difference in true nutrient digestibility; however, SSG and MIX provided the lowest acetate to propionate ratio and lower CH4 output than MIL and ORD. Thus, improved warm-season annual pastures (i.e., brown midrib sorghum × sudangrass) could provide a reasonable alternative to orchardgrass pastures during the summer months when such perennial cool-season grass species have greatly reduced productivity.

Comparison of rumen fluid inoculum vs. faecal inoculum on predicted methane production using a fully automated in vitro gas production system

The aim of the present study was to compare in vitro methane (CH4) production and other fermentation parameters from different substrates incubated either in rumen or faecal inoculum. Five different substrates were incubated in two different inocula and gas recordings were made using an automated in vitro gas production system. The substrates were: particulate matter obtained from reticulo-rumen (RR) digesta and faeces (FC) by wet sieving, timothy hay (H), first cut grass silage (S) and a mixture of grass silage and barley (50:50; SB). One gram of each substrate was incubated either in 60ml buffered rumen or faecal inoculum taken from Swedish lactating dairy cows for 48h. The results indicated that in vitro total gas production, predicted in vivo CH4 production and the ratio of CH4 production to total gas production were greater (P<0.01) for substrates incubated in rumen inoculum as compared to faecal inoculum. Mean of predicted in vivo CH4 production was greater for substrates incubated in rumen inoculum (23.5ml/g DM, 29.0ml/g OM) as compared to faecal inoculum (11.2ml/g DM, 14.3ml/g OM). Predicted CH4 production based on volatile fatty acids (VFA) stoichiometry equations (CH4VFA) showed no difference in CH4 per mol VFA (P=0.44) between the two sources of inoculum used for all substrates. Molar proportions of propionate were higher and that of butyrate were lower (P<0.01) for all substrates incubated in faecal inoculum compared to rumen inoculum. No difference (P=0.13) in molar proportions of acetate was observed. Digestibility of neutral detergent fibre (aNDFomD) and true organic matter digestibility (TOMD) were lower (P<0.01) for all substrates incubated in faecal inoculum compared to rumen inoculum. It can be concluded that using faecal inoculum tended to give lower values of predicted in vivo CH4 production as compared to rumen inoculum. The discrepancy between observed and stoichiometric CH4 production suggests an existence of acetogenesis in the hindgut.

Evaluation of various feedstuffs of ruminants in terms of chemical composition and metabolisable energy content.

Aim:The aim was to determine the chemical composition and metabolisable energy (ME) content of feedstuffs used in ruminant animals using in vitro method.Materials and Methods:A total of 18 feedstuffs used for ruminant feeding including cultivated non-leguminous fodders like maize, sorghum, pearl millet, and oat; leguminous fodders like cowpea and berseem; agro-industrial by-products such as wheat bran, deoiled rice bran, rice polish, wheat straw, and concentrates such as mustard oil cake, groundnut cake, soybean meal, cotton seed cake, grains like maize, oat, wheat, and barley were taken for this study. Chemical compositions and cell wall constituents of test feeds were determined in triplicate. The crude protein (CP) content was calculated as nitrogen (N) × 6.25. True dry matter digestibility (TDMD), true organic matter digestibility (TOMD), ME, and partitioning factor (PF) values were determined by in vitro gas production technique (IVGPT).Results:The CP content of non-leguminous fodders varied from 7.29% (sorghum) to 9.51% (maize), but leguminous fodders had less variation in CP. Oilseed cakes/meals had high CP and ether extract (EE) content than other feedstuffs except rice polish, which had 12.80% EE. Wheat straw contained highest fiber fractions than the other ingredients. ME content was highest in grains (wheat-12.02 MJ/kg) and lowest in wheat straw (4.65 MJ/kg) and other roughages. TDMD of grains and oilseed cakes/meals were higher than the fodders and agro-industrial by-products. The same trend was observed for TOMD.Conclusions:It was concluded that the energy feeds showed a great variation in chemical composition and ME content. The results of this study demonstrated that the kinetics of gas production of energy feed sources differed among themselves. Evaluation of various feedstuffs is helpful in balanced ration formulation for field animals and under farm conditions for better utilization of these commonly available feed resources.

Impact of a tannin extract on digestibility, ruminal fermentation and duodenal flow of amino acids in steers fed maize silage and concentrate containing soybean meal or canola meal as protein source

SUMMARYFour Holstein steers (297 ± 56 kg of body weight (BW)) fitted with duodenal cannula and rumen catheter, were housed in metabolism cages and used in a 4 × 4 Latin Square trial to evaluate the effect of both protein source andAcacia mearnsiitannin extract on digestibility, ruminal fermentation, rumen microbial protein synthesis, N utilization and on duodenal flow of individual amino acids. The diet was offered at restricted amount of 25 g of dry matter (DM)/kg BW and consisted of maize silage plus concentrate, in a proportion of 0·7:0·3 (DM basis) respectively. Concentrate was formulated with either soybean meal or canola meal as protein source, with or without 50 g/kg ofA. mearnsiitannin extract (i.e. 15 g/kg of total dietary DM). There was no effect of protein source on most variables. The apparent and true organic matter (OM) digestibilities, as well as neutral detergent fibre (NDF) digestibility were negatively affected by tannin extract inclusion without, however, affecting digestible OM intake. The amount of nitrogen (N) excreted in faeces increased whereas the urinary N excretion decreased in tannin extract treatments. No interaction time × treatment was detected for any rumen variable and no treatment effect was observed for rumen fluid pH and reducing sugars concentration. Rumen fluid concentration of ammonia N was lower for the canola meal plus tannin extract treatment. Rumen concentration ofα-amino compounds was not affected by tannin extract but was higher when canola meal was the protein source. The duodenal flow of OM, total N,α-amino N and non-ammonia non-microbial N increased with tannin extract inclusion, whereas the duodenal flow of microbial N was not affected by treatment. For both protein sources, the amount of most individual amino acids flowing to the duodenum increased due to tannin extract addition. In conclusion, the dietary inclusion of 15 g/kg DM of tannin extract fromA. mearnsiiimproved the amino acid supply independently of whether the protein source was canola meal or soybean meal, without affecting the amino acid profile, to steers fed maize silage plus concentrate, with a minor but significant impact on OM digestibility.

Retraction Note: Retraction note to: Nutritional evaluation of wheat straw treated with Crinipellis sp. in Sahiwal calves

Wheat straw was subjected to solid-state fermentation (SSF) with lignolytic white-rot fungus (WRF) Crinipellis sp. for 5 days to improve the nutritive value and digestibility. The fungal treatment caused a significant (P < 0.05) decrease in cell wall constituents viz., neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, lignin, and cellulose to the extent of 10.4, 11.2, 8.7, 8.7, and 12.1 %, respectively, with increase (P < 0.05) in crude protein (CP) (51.6%) and ash (25.8%) contents in fungal treated wheat straw (FT-WS) than untreated wheat straw (UT-WS). Further, in vitro gas production, in vitro true dry matter digestibility and in vitro true organic matter digestibility at 48 h, metabolizable energy (ME) content, microbial biomass production, and short-chain fatty acids synthesis were significantly (P < 0.05) higher in FT-WS. In vivo feeding trial in 10 Sahiwal calves (8–12 months) comprised of (1) control group (T1) fed with ad libitum chopped UT-WS and (2) treatment group (T2) offered with ad libitum chopped FT-WS, in addition to supplementation of groundnut cake and green berseem (Trifolium alexandrium) forage to both groups. Digestibility of nutrients for dry matter (DM), organic matter, CP, NDF, ADF, hemicellulose, cellulose, and total carbohydrates were significantly (P < 0.05) higher in T2 compared to T1. Moreover, daily DM (P < 0.05), digestible crude protein (P < 0.01), and ME intakes were also higher (P < 0.05) in group T2 with higher (P < 0.05) nitrogen (N) retention, which resulted in significantly (P < 0.05) higher average daily gain in body weight (135 vs. 102 g/day). It was concluded that SSF with WRF Crinipellis sp. holds potential in upgrading the nutritional worth of wheat straw for feeding growing calves.

Screening of plants from diversified natural grasslands for their potential to combine high digestibility, and low methane and ammonia production

A total of 156 plant species from 35 botanical families collected from diversified grasslands in the French Massif Central were screened in vitro for their potential to combine high nutritive value for ruminants and a reduced impact on the environment. The vegetative part of plants were analyzed for their chemical composition and incubated in a batch system containing buffered rumen fluid at 39°C for 24 h. The gas production and composition were recorded, and the fermentation end-product concentrations in the incubation medium and the in vitro true organic matter digestibility (IVTOMD) were determined. The results were expressed relative to perennial ryegrass (PRG) values used as a reference. We observed that no relationship between methane (CH4) and volatile fatty acids (VFA) was evidenced for 12 plants, the fermentation of these plants producing significantly less CH4 for a similar level of VFA production. In all, 13 plants showed 50% less CH4 production per unit of organic matter truly digested (OMTD) than PRG. Among these plants, two reduced CH4 by more than 80% and four species had an IVTOMD higher than 80%. The underlying modes of action seem to be different among plants: some result in an accumulation of H2 in the fermentation gas, but others do not. In terms of nitrogen (N) use efficiency, the fermentation of 37 plants halved the ratio between ammonia (N–NH3) and plant N content compared with PRG, of which six showed a complete absence of N–NH3 in the medium. Among these plants, four maintained the IVTDMO at values not significantly different from PRG (P>0.05). Considering the multi-criteria selection, 16 plants showed simultaneously a reduction of more than 80% in N–NH3 production and 30% in CH4 emission per unit of OMTD compared with PRG, including three with an IVTOMD higher than 80%. Overall, the botanical families that reduced simultaneously CH4 and N–NH3 most efficiently were the Rosaceae, Onagraceae, Polygonaceae and Dipsacaceae. The Onagraceae also gave high values for IVTOMD.

Identification of bioactive grassland plants for reducing enteric methane production and rumen proteolysis using an in vitro screening assay

The aim of this study was to conduct in vitro rumen fermentation assays on a large number of grassland plants to discriminate them on the basis of their potential to combine high nutritive value for ruminants and a reduced impact on the environment. In total, 156 plant species collected from diversified grasslands in the French Massif Central were screened by measuring several parameters, including in vitro true organic matter digestibility (IVTOMD), methane (CH4) production and ammonia nitrogen (N-NH3) in the incubation medium as an indicator of dietary protein degradation in the rumen. The results were expressed relative to perennial ryegrass (PRG) values used as a reference. We observed that the fermentation of 13 plants produced 50% less CH4 per unit of OM truly digested than did fermentation of PRG. Among these plants, two (Bidens tripartita subsp. Tripartite and Scrophularia nodosa) reduced CH4 by more than 80%. In terms of protein degradation, the fermentation of 37 plants halved the ratio between N-NH3 and plant N content compared with PRG, of which six had values below the detection level of the assay. Interestingly, 16 plants showed simultaneously a reduction of more than 80% in N-NH3 production and 30% in CH4 production, including three plants (Sedum telephium subsp. maximum, Oenothera biennis and Geranium sylvaticum) with an IVTOMD higher than 80%. This study has provided more knowledge about the use of lesser-known plants as whole plant forage by ruminants, and has identified candidate plants for potential use as additives in the form of plant extracts.

Nutritional Value of Acacia Amentacea and Parkinsonia Texana Grown in Semiarid Conditions

In order to evaluate the nutritional value of Parkinsonia texana and Acacia amentacea, two leguminosae species of the Tamaulipan scrubland, Northeastern Mexico, two experiments were carried out: the first tested the effects of season and browse species on chemical composition as nutritional variable to small ruminants; the second tested the effect of the addition of polyethylene glycol (PEG) on fermentation parameters. Foliage samples were collected from three sites. Data of chemical composition were analysed using analysis of variance for a bi-factorial arrangement, whereas the effect of PEG was analysed by a strip plot design. Results of chemical composition were affected by interacting factors season*species as individually they were significantly different (P<0.001). Addition of PEG affected (P<0.001) fermentation parameters. Significantly higher values of neutral detergent fibre (42%), condensed tannins (19%), purines (9 μmol), partitioning factor (PF) (6.1) and gross energy losses (GEL=6.7%) were found in A. amentacea, while P. texana gave higher crude protein (18%), in vitro true organic matter digestibility (82%), metabolisable energy (ME) [2.1 Mcal/kg dry matter (DM)], A (183 mL), c (0.07/h) and L (0.86 h). Addition of PEG increased ME, and affected (P<0.001) fermentation parameters A and c, while purines and PF decreased. Results indicate that chemical composition and fermentation parameters vary according to seasons and species. PEG addition increases the fermentation parameters, which indicates that PEG counteracts the detrimental effects of secondary components of samples. Data suggest that using both species combined could supply necessary nutritional requirements to small ruminants in the Tamaulipan scrubland.