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Globally, ruminant production contributes immensely to the supply of the highest quality and quantity of proteins for human consumption, sustenance of livelihoods, and attainment of food security. Nevertheless, the phasing out of antibiotics in animal production has posed a myriad of challenges, including poor growth, performance and nutrient utilization, pathogen colonization, dysbiosis, and food safety issues in ruminants. Probiotics (direct-fed microbials), comprising live microbial strains that confer health and nutritional benefits to the host when administered in appropriate quantities, are emerging as a viable, safe, natural and sustainable alternative to antibiotics. Although the mechanisms of action exerted by probiotics on ruminants are not well elucidated, dietary probiotic dosage to ruminants enhances development and maturation, growth and performance, milk production and composition, nutrient digestibility, feed efficiency, pathogen reduction, and mitigation of gastrointestinal diseases. However, the beneficial response to probiotic supplementation in ruminants is not consistent, being dependent on the microbial strain selected, combination of strains, dose, time and frequency of supplementation, diet, animal breed, physiological stage, husbandry practice, and farm management. Nonetheless, several studies have recently reported beneficial effects of probiotics on ruminant performance, health and production. This review conclusively re-iterates the need for probiotics inclusion for the sustainability of ruminant production. Considering the role that ruminants play in food production and employment, global acceptance of sustainable ruminant production through supplementation with probiotics will undoubtedly ensure food security and food safety for the world. © 2021 Society of Chemical Industry.

To investigate the transfer of pyrrolizidine alkaloids (PAs) from feed to milk, rumen-cannulated dairy cows were intra-ruminally fed with 200 g/day of dried plant material of either ragwort (mixture of Jacobaea vulgaris and Senecio inaequidens), common groundsel (Senecio vulgaris) or viper’s bugloss (Echium vulgare) for a period of 4 days. PA levels in the plant materials were 3767, 2792 and 1674 µg g−1 respectively. Feed intake, milk yield and several blood parameters indicative for liver function were not influenced by the treatment. When fed ragwort, increased levels of PAs were detected in the milk, in particular jacoline and an unidentified cyclic diester, possibly a hydroxylated metabolite from retrorsine. The latter was the most important PA in milk from cows fed common groundsel. For viper’s bugloss, echimidine was the most abundant identified PA but in addition several hydroxylated PA metabolites were detected. For ragwort, the overall PA transfer was estimated at 0.05% and 1.4% for jacoline (N-oxide). Transfer rates were similar for viper’s bugloss (0.05%) but lower for common groundsel (0.01%). Only a small portion of the administered PAs was quantified in milk, urine and faeces, with an overall balance of 4.5%, 2.9% and 5.8%, for ragwort, common groundsel and viper’s bugloss, respectively. Samples taken from the rumen indicated that the N-oxides were converted into the free bases, which was confirmed by in vitro studies with the same plant species incubated with ruminal fluid. These results confirm that the transfer of PAs to milk is relatively low but may be of concern for human health regarding the genotoxic and carcinogenic properties of these compounds. The transfer rate depends on the type of PAs present in the weeds. The incomplete balance of input vs output stresses the need to further investigate the metabolism and the potential transfer of metabolites into edible products.

BACKGROUND Information about the nutritive value, dry matter (DM) digestibility, and methane (CH4 ) emission potential of grass species is required for their optimal utilization in ruminant rations. The present study was designed: (i) to quantify the nutrient profile, mineral composition and in vitro dry matter digestibility (IVDMD) of winter grass species commonly available in northern Pakistan; and (ii) to measure the in vitro gas production (IVGP) and CH4 emission of the grass species during 72 h in vitro ruminal fermentation. Seven grass species, namely, Cenchrus ciliaris, Setaria anceps, Panicum antidotale, P. maximum, Pennisetum purpureum, Pennisetum orientale, and Atriplex lentiformis were assessed. RESULTS A high level of variability (P

This study investigated the chemical composition (proximate and Van Soest analysis) and in vitro gas production parameters of maize leaves and stems separately, and related the in vitro gas production parameters with the chemical composition, of thirteen maize cultivars. After harvest in September 2016, all plants were separated into two morphological fractions: leaves and stems. The crude protein (CP) content was greater, and the ratio of acid detergent lignin (ADL) to potentially rumen degradable fibre (calculated as the difference between neutral detergent fibre and ADL; ADL:pRDF) was lower in the leaves than in the stems in all 13 cultivars. For the leaves, the cumulative gas production between 3 and 20 hr (A2), representing cell wall fermentation in the rumen fluid, and the cumulative 72‐hr gas production (GP72), representing total organic matter (OM) degradation, were moderately to weakly correlated with the chemical composition, including hemicellulose, cellulose, ADL and CP content (R 2

An important aspect of live yeast (Saccharomyces cerevisiae) inclusion in the diets of ruminants is improved animal productivity. Inclusion of yeasts in ruminant diets may alter rumen microbes and their metabolites and promote a favorable intestinal microflora by increasing the population of beneficial microorganisms. Beneficial microbes compete for nutrients and attachment sites with pathogens, thereby reducing the growth of harmful microbes in the rumen. Yeasts enhance growth and average daily weight gain of animals by improving nutrients digestion and absorption. Probiotics can alter the fatty acid composition of meat and milk, and it is common knowledge that a lower fatty acid profile may directly confer health benefits to consumers by reducing harmful cholesterol levels in animal products and thus favorable to human nutrition. Furthermore, yeast probiotics have been shown to enhance immunity by inducing an immunomodulatory effect on the animal in addition to their ability to lower cholesterol, adhesion properties of the intestinal mucosa, and colonial resistance to strengthen gut integrity. This review highlights that yeast probiotics play a role in the ruminal microbial population dynamics, cholesterol-lowering ability and immunostimulatory potentials, yeast adhesion properties, and colonial resistance. Additional benefits include a healthy gut with concomitant increase in animal productivity, nutrient digestion, and absorption and general animal welfare. Overall, yeast probiotics appear to be a viable alternative to the use of antibiotics to improve animal welfare.

BACKGROUND White rot fungi have been used to improve the nutritive value of lignocellulose for ruminants. In feed analysis, the Van Soest method is widely used to determine the cell wall contents. To assess the reliability of this method (Method A) for determination of cell wall contents in fungal‐treated wheat straw, we compared a combined monosaccharide analysis and pyrolysis coupled to gas chromatography with mass spectrometry (Py‐GC/MS) (Method B). Ruminal digestibility, measured as in vitro gas production (IVGP), was subsequently used to examine which method explains best the effect of fungal pretreatment on the digestibility of wheat straw. RESULTS Both methods differed considerably in the mass recoveries of the individual cell wall components, which changed on how we assess their degradation characteristics. For example, Method B gave a higher degradation of lignin (61.9%), as compared to Method A (33.2%). Method A, however, showed a better correlation of IVGP with the ratio of lignin to total structural carbohydrates, as compared to Method B (Pearson's r of −0.84 versus −0.69). Nevertheless, Method B provides a more accurate quantification of lignin, reflecting its actual modification and degradation. With the information on the lignin structural features, Method B presents a substantial advantage in understanding the underlying mechanisms of lignin breakdown. Both methods, however, could not accurately quantify the cellulose contents – among others, due to interference of fungal biomass. CONCLUSION Method A only accounts for the recalcitrant residue and therefore is more suitable for evaluating ruminal digestibility. Method B allows a more accurate quantification of cell wall, required to understand and better explains the actual modification of the cell wall. The suitability of both methods, therefore, depends on their intended purposes. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The available agroindustry residues show high potential to be used as animal feedstuffs. This study aimed to valorise cowpea straw and discarded apple as potential ingredients for livestock diets through an ensiling process. Silage characteristics of cowpea straw (15%, as fresh) treated with Pleurotus citrinopileatus in association with discarded apple using or not a commercial inoculant were evaluated. At the moment of opening the silo, silages were stable and presented low pH values (≤ 4.2), high lactic acid concentration, no butyric acid, and aerobic stability averaged 134 h. The inoculated silage presented higher (p

Degradation of lignocellulose by selective white-rot fungi can significantly improve the nutritional value of high lignocellulose containing biomass by affecting the access of rumen microbes to structural carbohydrates. To determine if such treated biomass is stable in time to allow it to be conserved for subsequent feeding to ruminant animals, wheat straw (WS) pre-treated for 7 weeks with either Ceriporiopsis subvermispora or Lentinula edodes was stored anaerobically up to 10 weeks at different temperatures (24.7–52.4 °C). Substrates were subsequently analysed for changes in pH, titratable acidity, fibre composition, in vitro gas production (IVGP) and colour, as well as polar metabolites by GC–MS and ceriporic acids by LC–MS. The increased titratable acidity of fungal treated WS during storage indicated acidification of the straw. A significant decrease in hemicellulose and an increase in acid detergent lignin content was observed at 52.4 °C. No negative effect of the storage condition on the degradability of both fungal treated WS in rumen fluid was observed. A darker colour was observed for substrates incubated at higher temperatures, coinciding with a strong accumulation of several organic acids and sugars. A decrease in ceriporic acid A, B, C and G produced by C. subvermispora was observed when stored at 52.4 °C from week 2–10. The results show that, although the chemical composition changes, anaerobic storage of fungal treated WS at different temperatures does not affect its fermentation potential for ruminants.

A variety of secondary metabolites are formed and compounds released during the bioconversion of lignocellulosic biomass by white-rot fungi that can affect the nutritional value and acceptance of the biomass by ruminants. Changes in pH, ergosterol content, fibre and metabolites composition of wheat straw (WS) incubated with either Ceriporiopsis subvermispora or Lentinula edodes for up to 8 weeks were investigated. With increases in mycelium content, significant decreases in absolute amount of hemicellulose, acid detergent lignin and, to a lesser extent, cellulose were observed in both fungal treatments. Acidification mainly occurred within the first four weeks of incubation, coinciding with the largest changes in metabolites profile. Diverse compounds, including organic acids and soluble sugars increased or decreased with C. subvermispora and L. edodes treatment. None of the thirty-four common mycotoxins analyzed were detected in WS after 8 weeks of fungal incubation. These results provide important information for application of fungal treated WS that might affect animal acceptance and performance.

Objective: This study determined the optimal ratio of whole plant corn silage (WPCS) to corn stover (stems+leaves) silage (CSS) (WPCS:CSS) to reach the greatest profit of dairy farmers and evaluated its consequences with corn available for other purposes, enteric methane production and milk nitrogen efficiency (MNE) at varying milk production levels.Methods: An optimization model was developed. Chemical composition, rumen undegradable protein and metabolizable energy (ME) of WPCS and CSS from 4 cultivars were determined to provide data for the model.Results: At production levels of 0, 10, 20, and 30 kg milk/cow/d, the WPCS:CSS to maximize the profit of dairy farmers was 16:84, 22:78, 44:56, and 88:12, respectively, and the land area needed to grow corn plants was 4.5, 31.4, 33.4, and 30.3 ha, respectively. The amount of corn available (ton DM/ha/yr) for other purposes saved from this land area decreased with higher producing cows. However, compared with high producing cows (30 kg/d milk), more low producing cows (10 kg/d milk) and more land area to grow corn and soybeans was needed to produce the same total amount of milk. Extra land is available to grow corn for a higher milk production, leading to more corn available for other purposes. Increasing ME content of CSS decreased the land area needed, increased the profit of dairy farms and provided more corn available for other purposes. At the optimal WPCS:CSS, MNE and enteric methane production was greater, but methane production per kg milk was lower, for high producing cows.Conclusion: The WPCS:CSS to maximize the profit for dairy farms increases with decreased milk production levels. At a fixed total amount of milk being produced, high producing cows increase corn available for other purposes. At the optimal WPCS:CSS, methane emission intensity is smaller and MNE is greater for high producing cows.

Legume stovers may be an important feedstuff resource for animals, especially in the Mediterranean production systems. However, these stovers contain antinutritional factors, such as lignin, that may affect the growth performance of the animals. Studies with white-rot fungi showed their ability to increase the nutritional value of several agricultural wastes through changes in lignin structure facilitating the access to structural polysaccharides that are potentially digestible. This contributes to a better utilization of the diet’s nutrients and, consequently, to a better animal performance and health. The present work aimed at evaluating the effect of cowpea stover (Vigna unguiculata), untreated (US) or treated (TS) with Pleurotus citrinopileatus, on performance, digestibility, health and meat quality of growing rabbits. The TS treatment resulted from the inoculation of cowpea stover with Pleurotus citrinopileatus mycelium under solid-state fermentation for 22 days. Five experimental diets incorporating 0 (C), 50 (US50) and 100 g/kg (US100) of US and 50 (TS50) and 100 g/kg (TS100) of TS were used. Trials were conducted using 80 rabbits with 35 days old. The animals were randomly assigned to one of the 5 treatments and were slaughtered at 63 days of age. The incorporation of cowpea stover did not affect animal growth performances (mean daily weight gain of 44.4 g/kg; mean feed intake of 154 g/day; mean feed conversion rate of 3.46) or digestibility (mean dry matter digestibility of 564.8 g/kg; mean neutral detergent fibre digestibility of 369.6 g/kg). The orthogonal contrasts showed that the animals fed with US had a final live weight 5.0% lower (P = 0.04) than the ones fed TS (2214 vs. 2323 g). The TS diet allowed a 17.4% reduction (P = 0.03) in blood cholesterol levels. No influence (P > 0.05) of treatments was detected for carcass traits (mean chilled dressing out percentage of 59%) and meat quality parameters. There was a decrease in the caecal microbiota similarity index (P = 0.01) between US and TS diets. The incorporation up to 100 g/kg of treated cowpea stover with Pleurotus citrinopileatus in the rabbits’ compound feed showed potential to overcome the detrimental effect that the incorporation of the US has on the final live weight of growing rabbits. Further research on the specific effect of TS diets on cholesterol blood levels and shifts on the microbial population of the gastrointestinal tract should be assessed.

The increasing demand for animal protein by the growing world population intensifies the exploration of novel feed sources. This study evaluated the nutritional value of six intact seaweed species (i.e. the brown species Saccharina latissima, Laminaria digitata, and Ascophyllum nodossum, the red species Palmaria palmata, and Chondrus crispus and green species Ulva lactuca), collected from the coast of Ireland, Scotland and France as an ingredient for animal feed. The nutrient composition, in vitro digestibility, and in vitro gas production simulating rumen fermentation, were determined. The nutrient contents (g/kg dry matter), both between and within species, were highly variable, ranging from 45–248 for crude protein, 351–691 for non-starch polysaccharides, and 173–445 for ash. Overall, the brown seaweeds had the highest non-starch polysaccharides content, whereas samples of the red and green seaweeds had an amino acid content up to 265 g/kg dry matter. All samples had a substantial non-protein nitrogen fraction, varying from 0.12–0.29 of nitrogen. The fibre fractions of brown seaweeds showed different properties than land-based plants, as illustrated by a lower analysed neutral detergent fibre than acid detergent fibre content. The ileal organic matter and nitrogen digestibility, as well as the total tract organic matter digestibility (mean digestibility coefficients: 0.81, 0.89 and 0.88, respectively) were lower for all seaweeds compared to soybean meal (digestibility coefficients: 0.84, 0.98 and 0.97, respectively). S. latissima, L digitata, P. palmata and U. lactuca had a higher maximum gas production than alfalfa, but lower than sugar beet pulp. Based on the protein content and amino acid-pattern, intact P. palmata and U. lactuca would be a valuable protein source for farm animals, with the high non-starch polysaccharides and non-protein nitrogen contents and a low in vitro digestibility potentially limiting their use as a feed ingredient for monogastric species. The fermentability of L. digitata, S. latissima and P. palmata indicate that these intact seaweeds may have a higher nutritional value in ruminants. The high ash content in all seaweed species hampers the use of intact seaweed for both ruminants and monogastrics. Extraction of protein and other favourable components, while reducing the ash content, seems an important step towards seaweed inclusion in animal diets. Further identification and characterisation of seaweed polysaccharides is required to understand and improve the digestibility of seaweed fractions.

The successful application of fungal treated lignocellulosic biomass as an animal feed ingredient depends on its acceptance by animals. The objective of this study was to test the preference of fresh and stored fungal treated wheat straw (WS) by non-lactating Saanen goats. Three studies were conducted. Wheat straw was aerobically treated with Ceriporiopsis subvermispora (CS) and Lentinula edodes (LE) for 7 weeks before being stored at -20°C (fresh CS [CSf], fresh LE [LEf]) until use. The CSf and LEf were also anaerobically stored at 54°C (stored CS [CSs], stored LE [LEs]) for 7 weeks before being frozen at -20°C until use. In study 1, preference for individual feedstuffs was tested and included grass silage (GS), maize silage (MS), CSf, LEf and WS. Goats showed a strong preference for GS and were more reluctant to consume MS. Minor amounts of CSf, LEf and WS were consumed even when the preference time was extended to 2 h. Study 2 compared the preference of CSf, LEf and WS when included at 50% (as is basis) in a GS/MS based feed over 6 days. Goats had a higher (P < 0.05) intake rate of the CSf and LEf than the WS containing feed, with no significant difference observed between CSf and LEf. In study 3, the preference of goats between diets containing (50% as is basis) fresh and stored fungal treated WS was investigated. In an identical study design to study 2, the goats showed a higher intake rate for the CSs and LEs containing feeds. Wheat straw treated with C. subvermispora and L. edodes were significantly less preferred to GS and MS. This feeding study showed that fungal treated WS can be used as a major part in a diet for goat and the storage increases its palatability.

BACKGROUND: This study investigated the ruminal degradability of various wheat straw types by the white-rot fungi Ceriporiopsis subvermispora (CS) and Lentinula edodes (LE). Different cultivars (CV) of wheat straw at different maturity stages (MS) were treated with the fungi for 7 weeks and assessed for chemical composition and in vitro gas production (IVGP). RESULTS: Both fungi showed a more pronounced degradation of lignin on a more mature straw (MS3; 89.0%) in comparison with the straw harvested at an earlier stage (MS1; 70.7%). Quantitative pyrolysis coupled to gas chromatography and mass spectrometry, using 13C lignin as an internal standard 13C-IS Py-GC/MS revealed that lignin in more mature straw was degraded and modified to a greater extent. In contrast, cellulose was less degraded in MS3, as compared to MS1 (8.3% versus 14.6%). There was no effect of different MS on the IVGP of the fungus-treated straws. Among the different straw cultivars, the extent of lignin degradation varied greatly (47% to 93.5%). This may explain the significant (P

The aim of this study was to evaluate the effect of the level of alfalfa in the diet on feed intake and digestibility of two types of rabbits, wild (Oryctolagus cuniculus algirus) vs. domestic (O. cuniculus cuniculus). Ten wild (W; mean LW = 927 g) and 10 domestic (D; mean LW = 4,645 g) adult rabbit does were fed ad libitum two pelleted diets: a control diet (C) with 15% of dehydrated alfalfa hay (as feed basis) and a test diet (A) with 36% of dehydrated alfalfa hay (as feed basis), according to a change-over design. Wild does dry matter (DM) intake per kg live weight (BW) was 55% higher (p < .001) than the intake of the D ones (58 g vs. 37 g DM per kg BW respectively). However, no difference (p > .05) was found when intake was expressed per kg0.75 BW (ca. 56 g DM) and tended to be higher (p = .07) in D does when expressed per kg0.67 BW (62 g vs. 55 g DM). Domestic does showed a higher (p < .05) DM, organic matter, crude energy and neutral detergent fibre digestibility (3; 2; 3; 3 percentage points respectively) than W does. The amount of nutrients and energy digested by D does was lower per kg BW (p < .001), similar per kg0.75 BW (p > .05) and tended to be higher per kg0.67 BW (p < .1) than in W does. The diet content of alfalfa did not affect (p > .05) the feed intake nor the diet digestibility. This study suggests that W rabbits exhibit a higher intake per kg BW and a lower digestibility than their D counterparts, which results in similar digestible nutrient and energy intake per kg BW powered to 0.75. The nutritive value of dehydrated alfalfa for rabbits, evaluated through intake and digestibility, seems to be equivalent to their base diets (forage plus concentrate).

Background: No attention has been paid so far to the preservation of fungal-treated lignocellulose for longer periods. In the present study, we treated wheat straw (WS) with the white-rot fungi Ceriporiopsis subvermispora and Lentinula edodes for 8 weeks and assessed changes in pH, chemical composition and in vitro gas production (IVGP) weekly. Fungal-treated WS was also stored for 64 days 'as is', with the addition of lactic acid bacteria (LAB) or with a combination of LAB and molasses in airtight glass jars mimicking ensiling conditions.; Results: Both fungi significantly reduced the lignin and hemicellulose content of WS, and increased the cellulose content. The IVGP increased with increasing time of incubation, indicating the increase in digestibility. Both fungi lowered the pH of WS under 4.3, which guarantees an initial and stable low pH during anaerobic storage. Minor changes in fibre composition and IVGP were observed for stored L. edodes treated WS, whereas no change occurred for C. subvermispora.; Conclusion: It is possible to conserve C. subvermispora and L. edodes treated straw under anaerobic condition without additives up to 64 days. This finding is important for practical application to supply fungi-treated feed to ruminant animals for a prolonged period. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.; © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Background: The relationship between the chemical and molecular properties - in particular the (acid detergent) lignin (ADL) content and composition expressed as the ratio between syringyl and guaiacyl compounds (S:G ratio) - of maize stems and in vitro gas production was studied in order to determine which is more important in the degradability of maize stem cell walls in the rumen of ruminants. Different internodes from two contrasting maize cultivars (Ambrosini and Aastar) were harvested during the growing season.; Results: The ADL content decreased with greater internode number within the stem, whereas the ADL content fluctuated during the season for both cultivars. The S:G ratio was lower in younger tissue (greater internode number or earlier harvest date) in both cultivars. For the gas produced between 3 and 20 h, representing the fermentation of cell walls in rumen fluid, a stronger correlation (R2 = 0.80) was found with the S:G ratio than with the ADL content (R2 = 0.68). The relationship between ADL content or S:G ratio and 72-h gas production, representing total organic matter degradation, was weaker than that with gas produced between 3 and 20 h.; Conclusion: The S:G ratio plays a more dominant role than ADL content in maize stem cell wall degradation. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.; © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Aim The present study evaluated differences between two strains of Ceriporiopsis subvermispora on improving the nutritive value and in vitro degradability of wheat straw. Methods and Results Wheat straw was treated with the fungi for 7 weeks. Weekly samples were analyzed for ergosterol content, in vitro gas production (IVGP), chemical composition and lignin degrading enzyme activity. Ergosterol data showed CS1 to have a faster initial growth than CS2 and reaching a stationary phase after 3 weeks. The IVGP of CS1-treated wheat straw exceeded the control earlier than CS2 (4 vs 5 weeks). CS1 showed a significantly higher (P < 0.001) selectivity in lignin degradation compared to CS2. Both strains showed peak activity of laccase and manganese peroxidase (MnP) at week 1. CS1 showed a significantly higher (P < 0.001) laccase activity, but lower (P = 0.008) MnP activity compared to CS2. Conclusion Both CS strains improved the nutritive value of wheat straw. Variation between strains was clearly demonstrated by their growth pattern and enzyme activities. Significance and Impact of Study The differences among the two strains provide an opportunity for future selection and breeding programs in improving the extent and selectivity of lignin degradation in agricultural biomass. This article is protected by copyright. All rights reserved.

Lignin inhibitory effects within the cell wall structure constitute a serious drawback in maximizing the utilization of fibrous feedstuffs in animal feeding. Therefore treatments that promote efficient delignification of these materials must be applied. This study evaluated the potential of white-rot fungi to upgrade the nutritive value of cowpea stover for rabbit feeding.; Results: There was an increase in the crude protein content of all substrates as a result of fungi treatments, reaching a net gain of 13% for Pleurotus citrinopileatus incubation. Overall, net losses of dry and organic matter occurred during fungi treatments. Although the fiber content remained identical, higher consumption of cell wall contents was measured for P. citrinopileatus incubation (between 40 and 45%). The incubation period did not influence lignin degradation for any of the fungi treatments. Differences within the fungal degradation mechanisms indicate that P. citrinopileatus treatment was most effective, enhancing in vitro organic matter digestibility by around 30% compared with the control.; Conclusion: Treatment of cowpea stover with P. citrinopileatus led to an efficient delignification process which resulted in higher in vitro organic matter digestibility, showing its potential in the nutritional valorization of this feedstuff. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.

The potential of an in vitro gas production (GP) system to predict the in vivo enteric methane (CH4) production for various ryegrass-based silages was evaluated, using adapted rumen fluid from cows. Rumen fluid from 12 lactating rumen-cannulated Holstein-Friesian cows were used for in vitro incubations and compared with in vivo CH4 production data derived from the same cows fed the same grass silages. The cows consumed a total mixed ration consisting of six different grass silages and concentrate at an 80:20 ratio on a dry matter (DM) basis. The grass silages differed in plant maturity at harvest (28, 41 and 62 days of regrowth) and N fertilisation (65 and 150 kg of N/ha). Rumen fluid from cows consuming each of the six grass silages was used to determine the in vitro organic matter (OM) fermentation and in vitro CH4 synthesis, using an automated GP technique. In vitro GP decreased with increasing maturity of the grass. In vitro CH4 production, expressed either in ml/g of OM, in ml/g of degraded OM (DOM) or as a% of the total GP, increased with increased N fertilisation (P < 0.05). Maturity of grass at harvest did not affect the CH4 synthesis expressed in ml/g of DOM and CH4 expressed as% of the total gas, whereas N fertilisation increased the in vitro CH4 synthesis, expressed in any unit. The in vitro data correlated poorly with the in vivo data. Across the six grass silages tested, the in vitro CH4 production, expressed in ml/g of OM after 8, 12, 24, and 72 h of incubation did not correlate with the in vivo enteric CH4 production, expressed in g/kg of DM intake (R2 = 0.01–0.08). Stepwise multiple regression showed a weak, but positive correlation between the observed in vivo CH4 synthesis, expressed in g/kg FPCM and the predicted CH4 per kg FPCM, using the amount of in vitro organic matter degraded (R2 = 0.40; P = 0.036). In vitro gas and CH4 parameters did not improve the accuracy of the prediction of the in vivo CH4 data.

The effect of ensiling and fungal treatment on the chemical composition and on in vitro gas production, an indication of rumen degradability, of maize stems was studied. Stems from two maize cultivars (LG30211 and MZP8057) were separated into three parts: upper (above internode 12 up to and including internode 15), middle (above internode 8 up to and including internode 11), and lower stem (above internode 5 up to and including internode 7). The three parts of the stems were ensiled for 1, 2, 4, and 8 weeks and the lower stem was treated with the white-rot fungi Lentinula edodes and Pleurotus eryngii for 3, 6, and 9 weeks. The dry matter content decreased and the acid detergent fibre (ADF) and acid detergent lignin (ADL) content increased from the top to the bottom in the stem. Upon ensiling, the neutral detergent fibre, ADF and ADL content increased. The gas production between 3 and 20 h, a measure of cell wall degradability in rumen fluid, did not change after ensiling, but gas production within 3 h and within 72 h decreased after ensiling. The acetic acid content and the proportion of ammonia-N in total N increased, and pH decreased, after 1 week of ensiling and did not show a clear trend from 1 to 8 weeks. The ADL and cellulose content of the lower part of the stem of both maize cultivars increased after fungal treatment and the hemicellulose content decreased except for the lower stem of MZP8057 treated with P. eryngii. The ratio of syringyl to guaiacyl compounds increased after fungal treatment. The gas production between 3 and 20 h and within 72 h decreased after fungal treatment. Both ensiling and fungal treatment cannot improve the degradability of the investigated maize stems.

The growing world population demands an increase in animal protein production. Seaweed may be a valuable source of protein for animal feed. However, a biorefinery approach aimed at cascading valorisation of both protein and non-protein seaweed constituents is required to realise an economically feasible value chain. In this study, such a biorefinery approach is presented for the green seaweed Ulva lactuca containing 225 g protein (N × 4.6) kg−1 dry matter (DM). The sugars in the biomass were solubilised by hot water treatment followed by enzymatic hydrolysis and centrifugation resulting in a sugar-rich hydrolysate (38.8 g L−1 sugars) containing glucose, rhamnose and xylose, and a protein-enriched (343 g kg−1 in DM) extracted fraction. This extracted fraction was characterised for use in animal feed, as compared to U. lactuca biomass. Based on the content of essential amino acids and the in vitro N (85 %) and organic matter (90 %) digestibility, the extracted fraction seems a promising protein source in diets for monogastric animals with improved characteristics as compared to the intact U. lactuca. The gas production test indicated a moderate rumen fermentation of U. lactuca and the extracted fraction, about similar to that of alfalfa. Reduction of the high content of minerals and trace elements may be required to allow a high inclusion level of U. lactuca products in animal diets. The hydrolysate was used successfully for the production of acetone, butanol, ethanol and 1,2-propanediol by clostridial fermentation, and the rhamnose fermentation pattern was studied. Electronic supplementary material The online version of this article (doi:10.1007/s10811-016-0842-3) contains supplementary material, which is available to authorized users.

Different numbers of animals have been used in different studies to cover the variation between individual animals in in situ rumen degradation characteristics of maize and grass silages. The objective of this study was to determine whether three cows are sufficient or not to cover the variation between individual cows in in situ rumen degradation characteristics of dry matter (DM), organic matter (OM), crude protein (CP), starch and neutral detergent fibre (NDF) for maize and grass silages. Fifteen maize and 15 grass silage samples, with a broad range in chemical composition, were selected. The maize and grass silage samples were incubated in the rumen for 2, 4, 8, 16, 32, 72 and 336 h, using the nylon bag technique. Three cows were used for nylon bag incubation of maize silages and three other cows for grass silages. The variation between individual cows was found significant (P 0.05) differences were found for all other parameters of DM, OM, CP, starch and NDF. The variation between individual cows was found non-significant (P > 0.05) for rumen undegradable fraction (U), potentially rumen degradable fraction (D), kd and ED of DM, OM, CP and NDF of grass silages. The results of this study indicate that the use of three cows for nylon bag incubations of grass silages is sufficient whereas the use of three cows for nylon bag incubations of maize silages is not sufficient to cover variation between the individual cows.

A rapid and complete colonization of lignocellulosic biomass by white-rot fungi is a prerequisite for an efficient and contamination free delignification. To improve the colonization, mycelium growth and delignification by Ceriporiopsis subvermispora and Lentinula edodes of wheat straw, with addition of 2, 4, 6 and 10% of wheat bran for 0, 2, 4, 8 and 12 weeks, was evaluated. The ergosterol content, chemical composition and in vitro gas production (IVGP) by ruminal microorganisms were determined. The fungal biomass and starch amount was significantly (P < 0.001) affected by the inclusion level of wheat bran and incubation time. An increase in added wheat bran increased the fungal biomass with different effects observed for the two fungi. The added starch from the wheat bran was degraded by C. subvermispora, mainly during the first two weeks (up to 44%), whereas, L. edodes degraded starch during 12 weeks up to 83%. The supplementation of wheat bran, however, did not affect (P > 0.05) the amount of hemicellulose and lignin at the end of the incubation. There was no significant effect of wheat bran addition on the IVGP for the two fungal treatments. Supplementation of wheat straw with wheat bran resulted in a quicker fungal colonization, which is useful for C. subvermispora, a fungus that forms only thin mycelium and is more prone to contamination than L. edodes.

Starch is considered a major nutritional factor of maize (Zea mays L.) kernels, and can be influenced by the type of endosperm. The effects of endosperm type (vitreous and non-vitreous) and type of soil (clay and sand) on the starch content of kernels of maize, and on the in vitro degradation of starch were investigated in the rumen fluid after harvesting at 6 different maturity stages during 2008 and five different maturity stages in 2009. Starch degradation, in rumen fluid, was determined after 6 h, 12 h and 20 h of incubation, using the technique of gas production. A positive linear relationship was observed during gas production (ml gas/g organic matter) and starch degradation (g kg-1 starch) at all incubation times, with starch contents of maize kernels to a certain limit of starch accumulation (i.e. at starch contents 451-519 g/kg OM) and negative relationship afterwards. This suggests significant effects of maturity on ruminal starch degradation of maize kernels. At each harvest date, ruminal starch degradation of maize kernels was affected by crop genotype as well as soil type. The in vitro ruminal degradation potential of starch in maize kernels was influenced by the nature of the endosperm, with a higher degradation of non-vitreous kernels than of vitreous kernels. The rumen starch degradation was also influenced by type of soil, with better degradation on clay than sandy soil. For all the incubation times and maturity stages the effects of genotype, soil type and maturity stage were consistent in rumen fluid.

The relationship between in vitro rumen CH4 production of grass silages, using the gas production technique, and in vivo data obtained with the same cows and rations in respiration chambers was investigated. Silages were made from grass harvested in 2013 on May 6th, May 25th, July 1st and July 8th. The grass silages were used to formulate four different rations which were fed to 24 cows in early and late lactation, resulting in a slightly different dry matter intake (DMI; 16.5 kg/day vs. 15.4 kg/day). The experimental rations consisted of 70% grass silage, 10% maize silage, and 20% concentrates on a dry matter basis. Cows were adapted to the rations for 17 days before rumen fluid was collected via oesophageal tubing, and in vitro gas and CH4 production were analysed. In vitro total gas and CH4 production of the (ensiled) grass expressed as ml/g OM decreased with advancing maturity of the grass. The in vitro CH4 production after 48 hr of incubation expressed in ml/g OM did not correlate with the in vivo CH4 production expressed in g/kg organic matter intake or g/kg DMI (R2 = .00-.18, p ≥ .287). The differences in CH4 emission per unit of intake observed in vivo were rather small between the different rations, which also contributed to the observed poor relationship. Utilizing stepwise multiple regression improved the correlation only slightly. In vitro gas and CH4 production varied based on whether donor cows were previously adapted to the respective ration or not, suggesting that careful adaption to the experimental diet should be envisaged in in vitro gas and CH4 production experiments.

BACKGROUND This study investigated the ruminal degradability of various wheat straw types by the white‐rot fungi Ceriporiopsis subvermispora (CS) and Lentinula edodes (LE). Different cultivars (CV) of wheat straw at different maturity stages (MS) were treated with the fungi for 7 weeks and assessed for chemical composition and in vitro gas production (IVGP). RESULTS Both fungi showed a more pronounced degradation of lignin on a more mature straw (MS3; 89.0%) in comparison with the straw harvested at an earlier stage (MS1; 70.7%). Quantitative pyrolysis coupled to gas chromatography and mass spectrometry, using 13C lignin as an internal standard 13C‐IS Py‐GC/MS revealed that lignin in more mature straw was degraded and modified to a greater extent. In contrast, cellulose was less degraded in MS3, as compared to MS1 (8.3% versus 14.6%). There was no effect of different MS on the IVGP of the fungus‐treated straws. Among the different straw cultivars, the extent of lignin degradation varied greatly (47% to 93.5%). This may explain the significant (P < 0.001) effect of cultivar on the IVGP of the fungal‐treated straws. Regardless of the factors tested, both fungi were very capable of improving the IVGP of all straw types by 15.3% to 47.6%, (as compared to untreated straw), with CS performing better than LE – on different MS (33.6% versus 20.4%) and CVs (43.2% versus 29.1%). CONCLUSION The extent of lignin degradation caused by fungal treatment was more pronounced on the more mature and lignified straw, while variable results were obtained with different cultivars. Both fungi were capable of improving the IVGP of various straw types. © 2018 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Aim: In this study, the biological variation for improvement of the nutritive value of wheat straw by 12 Ceriporiopsis subvermispora, 10 Pleurotus eryngii and 10 Lentinula edodes strains was assessed. Screening of the best performing strains within each species was made based on the in vitro degradability of fungal-treated wheat straw. Methods and Results: Wheat straw was inoculated with each strain for 7 weeks of solid state fermentation. Weekly samples were evaluated for in vitro gas production (IVGP) in buffered rumen fluid for 72 h. Out of the 32 fungal strains studied, 17 strains showed a significantly higher (P < 0·05) IVGP compared to the control after 7 weeks (227·7 ml g−1 OM). The three best Ceriporiopsis subvermispora strains showed a mean IVGP of 297·0 ml g−1 OM, while the three best P. eryngii and L. edodes strains showed a mean IVGP of 257·8 and 291·5 ml g−1 OM, respectively. Conclusion: Ceriporiopsis subvermispora strains show an overall high potential to improve the ruminal degradability of wheat straw, followed by L. edodes and P. eryngii strains. Significance and Impact of the Study: Large variation exists within and among different fungal species in the valorization of wheat straw, which offers opportunities to improve the fungal genotype by breeding.

Besides their unique ability to depolymerize cell wall components, white-rot fungi are known to assimilate nitrogenous compounds from substrates. This modification may change protein solubility and fermentation in the rumen. To investigate this, the crude protein (CP) in fungal treated wheat straw (3 fungal species, 2 strains each) was fractioned according to the Cornell Net Carbohydrate and Protein System (CNCPS) and assessed for in vitro protein fermentation using a modified gas production technique (IVGPN). Results showed that fungi increased fraction A (instantaneously soluble CP; ∼2.6 times) and B1 (rapidly degradable; ∼1.2 times); and decreased the slowly degradable fraction B3 (∼41.6%) and unavailable fraction C (∼48.3%). The IVGPN of straw treated with Ceriporiopsis subvermispora strains were not different to the control, but increased by 30.2 to 47.1% in Pleurotus eryngii and Lentinula edodes strains. The IVGPN was significantly (P < 0.01) correlated to all fractions of CP, except fraction B1 and B2 (intermediately degradable). All fungi also increased the arginine (∼56%) and lysine (∼15%) contents. This study shows the importance of assessing the protein solubilization by different fungal strains, which can uncover unique mechanisms in the cell wall depolymerization.

Background The white-rot fungi Ceriporiopsis subvermispora (Cs), Pleurotus eryngii (Pe), and Lentinula edodes (Le) have been shown to be high-potential species for selective delignification of plant biomass. This delignification improves polysaccharide degradability, which currently limits the efficient lignocellulose conversion into biochemicals, biofuels, and animal feed. Since selectivity and time efficiency of fungal delignification still need optimization, detailed understanding of the underlying mechanisms at molecular level is required. The recently developed methodologies for lignin quantification and characterization now allow for the in-depth mapping of fungal modification and degradation of lignin and, thereby, enable resolving underlying mechanisms. Results Wheat straw treated by two strains of Cs (Cs1 and Cs12), Pe (Pe3 and Pe6) and Le (Le8 and Le10) was characterized using semi-quantitative py-GC–MS during fungal growth (1, 3, and 7 weeks). The remaining lignin after 7 weeks was quantified and characterized using 13C lignin internal standard based py-GC–MS and whole cell wall HSQC NMR. Strains of the same species showed similar patterns of lignin removal and degradation. Cs and Le outperformed Pe in terms of extent and selectivity of delignification (Cs ≥ Le >> Pe). The highest lignin removal [66% (w/w); Cs1] was obtained after 7 weeks, without extensive carbohydrate degradation (factor 3 increased carbohydrate-to-lignin ratio). Furthermore, though after treatment with Cs and Le comparable amounts of lignin remained, the structure of the residual lignin vastly differed. For example, Cα-oxidized substructures accumulated in Cs treated lignin up to 24% of the total aromatic lignin, a factor two higher than in Le-treated lignin. Contrarily, ferulic acid substructures were preferentially targeted by Le (and Pe). Interestingly, Pe-spent lignin was specifically depleted of tricin (40% reduction). The overall subunit composition (H:G:S) was not affected by fungal treatment. Conclusions Cs and Le are both able to effectively and selectively delignify wheat straw, though the underlying mechanisms are fundamentally different. We are the first to identify that Cs degrades the major β-O-4 ether linkage in grass lignin mainly via Cβ–O–aryl cleavage, while Cα–Cβ cleavage of inter-unit linkages predominated for Le. Our research provides a new insight on how fungi degrade lignin, which contributes to further optimizing the biological upgrading of lignocellulose.

The effect of Agolin Ruminant, a blend of essential oils, on methane (CH 4 ) emissions were investigated in two in vivo experiments and in four in vitro experiments. In the in vivo experiments, four lactating dairy cows and four beef heifers were supplemented 0.2 g/d of the essential oils ( ca. 2–4 ppm m / v ) during an eight-weeks period, where the first two weeks served as control (no essential oils supplementation). In dairy cattle, essential oils tended to decrease the daily CH 4 emissions (g/d) and CH 4 relative to dry matter intake (g/kg DMI) by 15% and 14%, respectively, after 6 weeks of supplementation ( P =0.07), but no difference was observed for CH 4 relative to milk production (g/kg milk) ( P =0.64) or CH 4 relative to bodyweight (g/kg BW) ( P =0.12). In the in vivo experiment with beef cattle daily CH 4 emissions and CH 4 relative to DMI did not change when supplemented the essential oils at a dose of 0.2 g/d (numerical decreases of 10 and 11% for g CH 4 /d and g CH 4 /kg DMI, respectively) but CH 4 relative to body weight tended to decrease by 20% after 6 weeks of supplementation ( P =0.07). The in vitro experiments were expected to replicate the results observed in vivo. However, no decrease in CH 4 production was observed in 24 h batch incubations at concentrations up to 30 ppm ( m / v ). A longer contact time between the essential oils (15 and 30 ppm) and the feedstuff (essential oils added ca . 16 h prior the start of the incubation) did not elicit any effect on CH 4 production and was not different from addition immediately prior to the start of the incubation. Longer incubation time (96 h and 14 d) and regular supply of both substrate and additive in a consecutive batch incubation system did not induce CH 4 inhibition up to essential oils doses of 30 ppm ( m / v ) and hence, also were not able to replicate in vivo results. Using the gas production technique (GPT) methane was inhibited by 17% with an essential oils dose of 30 ppm after 24 h, but this decrease was not constant across all times during the 72 h incubation. The blend of essential oil was effective reducing daily emissions of methane in dairy cattle and emissions relative to body weight in beef cattle, interestingly, these effects were not observed in vitro regardless of the techniques used to replicate in vivo results. This might be due to differences in the mode of action of the essential oils in vitro and in vivo , which merits attention for future research.

BACKGROUND No attention has been paid so far to the preservation of fungal‐treated lignocellulose for longer periods. In the present study, we treated wheat straw (WS) with the white‐rot fungi Ceriporiopsis subvermispora and Lentinula edodes for 8 weeks and assessed changes in pH, chemical composition and in vitro gas production (IVGP) weekly. Fungal‐treated WS was also stored for 64 days ‘as is’, with the addition of lactic acid bacteria (LAB) or with a combination of LAB and molasses in airtight glass jars mimicking ensiling conditions. RESULTS Both fungi significantly reduced the lignin and hemicellulose content of WS, and increased the cellulose content. The IVGP increased with increasing time of incubation, indicating the increase in digestibility. Both fungi lowered the pH of WS under 4.3, which guarantees an initial and stable low pH during anaerobic storage. Minor changes in fibre composition and IVGP were observed for stored L. edodes treated WS, whereas no change occurred for C. subvermispora. CONCLUSION It is possible to conserve C. subvermispora and L. edodes treated straw under anaerobic condition without additives up to 64 days. This finding is important for practical application to supply fungi‐treated feed to ruminant animals for a prolonged period. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

To gain knowledge on the precision of an in vitro method for characterisation of the fermentability of dietary fibres, this study aimed to evaluate the repeatability and reproducibility of such a method. Substrates used were citrus pectin (CP), fructo-oligosaccharides (FOS), guar gum (GG), sugar beet pulp (SBP) and wheat middlings (WM). Each substrate was incubated with faecal inoculum from five cats with three replicates for each substrate–cat combination. Gas production was measured continuously during the 48 h incubation and SCFA and organic matter disappearance (only SBP and WM) were determined after incubation. Four consecutive runs were performed. The within-run variability (repeatability) was generally lower for the more simple and pure substrates (CP, FOS, GG) than for the more complex substrates containing mixtures of fibres (SBP, WM). Replicates showed high variability, in particular for SCFA profiles and parameters of gas production kinetics. The between-run CV (reproducibility) for the measured parameters were, in general, below 10 % for CP, FOS and GG and higher values were obtained for SBP and WM. It is concluded that for precise dietary fibre characterisation, the number of replicates should be multiple and adjusted according to the variability of the parameters of interest and the complexity of fibres. The method yielded reproducible results with some variation in absolute values obtained, which may have an impact on the significance level of the differences among substrates.

11 páginas.-- 4 figuras.-- 3 tablas.-- 32 referencias..-- Supplementary data related to this article can be found at http://dx.doi.org/10.1016/j.biombioe.2017.07.003, Wheat straw and oak wood chips were incubated with Ceriporiopsis subvermispora and Lentinula edodes for 8 weeks. Samples from the fungal treated substrates were collected every week for chemical characterization. L. edodes continuously grew during the 8 weeks on both wheat straw and oak wood chips, as determined by the ergosterol mass fraction of the dry biomass. C. subvermispora colonized both substrates during the first week, stopped growing on oak wood chips, and resumed growth after 6 weeks on wheat straw. Detergent fiber analysis and pyrolysis coupled to gas chromatography/mass spectrometry showed a selective lignin degradation in wheat straw, although some carbohydrates were also degraded. L. edodes continuously degraded lignin and hemicelluloses in wheat straw while C. subvermispora degraded lignin and hemicelluloses only during the first 5 weeks of treatment after which cellulose degradation started. Both fungi selectively degraded lignin in wood chips. After 4 weeks of treatment, no significant changes in chemical composition were detected. In contrast to L. edodes, C. subvermispora produced alkylitaconic acids during fungal treatment, which paralleled the degradation and modification of lignin indicating the importance of these compounds in delignification. Light microscopy visualized a dense structure of wood chips which was difficult to penetrate by the fungi, explaining the relative lower lignin degradation compared to wheat straw measured by chemical analysis. All these changes resulted in an increased in in vitro rumen degradability of wheat straw and oak wood chips. In addition, more glucose and xylose were released after enzymatic saccharification of fungal treated wheat straw compared to untreated material., This research was part of a large program entitle: “Waste to Resource” and this was supported by the Dutch Technology Foundation (STW), which is part of the Netherlands Organization for Scientific Research (NWO), which is partly funded by the Dutch Ministry of Economic Affairs. This specific research reported here was part of the project entitled: “Increasing the utilization of organic waste and low value feeds with the help of lignin degrading fungi” (project number 111611). This particular research was co-sponsored by Agrifirm, Purac, DSM, Den Ouden, Hofmans, the Dutch commodity boards for dairy and horticulture, and Wageningen University. We would like to thank Agrifirm for analyzing part of the samples for dry matter, ash, crude protein, NDF and ADF. We would like to thank Dyadic Nederland BV for supplying the CMAX3 enzyme mixture. This study has also partially been funded by the Spanish projectsAGL2011-25379, AGL2014-53730-R and CTQ2014-60764-JIN (co-financed by FEDER funds), the CSIC project2014-40E-097 and the EU-project INDOX (KBBE-2013-7-613549).

The degradation of starch largely determines the feeding value of maize (Zea mays L.) for dairy cows. Normally, maize kernels are dried and ground before chemical analysis and determining degradation characteristics, whereas cows eat and digest fresh material. Drying the moist maize kernels (consisting mainly of starch) at high temperatures can influence their physical properties and thus their degradation dynamics in the rumen. We compared the in vitro degradability of dried maize kernels with that of fresh kernels after incubation in rumen fluid. Maize kernels were obtained from genotypes diverse in starch structure, composition and type of endosperm. These genotypes were grown in greenhouses at different temperatures during starch accumulation, and harvested at different maturity stages, in two experiments. Starch content was assessed using the amyloglucosidase method. Fermentation in rumen fluid was measured using an in vitro gas production technique. Starch degradation of the kernels was calculated after 6, 12 and 20 h of incubation in rumen fluid. Oven-drying influenced (P < 0.0001) the in vitro degradation of starch in maize kernels at the different incubation times, with more starch being degraded in the fresh than in the oven-dried maize kernels, although the differences were small (11–15%). There was a consistent interaction (P < 0.009 to 0.0002) between oven-drying and genotype, with the high-amylose genotype showing larger effects of oven-drying than the other genotypes. The vitreous genotype showed a lower starch degradation than the non-vitreous type. At earlier maturity stages, the difference between oven-dried and fresh kernels was larger than at later maturity stages. The temperature during grain filling affected (P < 0.0001) starch degradation but did not affect the difference between fresh and oven-dried samples. Oven-drying reduced the in vitro rumen starch degradation of maize kernels regardless of growing conditions, genotype and maturity stage, but its effect depends on genotype and maturity.

Maize silage has become the major forage component in the ration of dairy cows over the last few decades. This review provides information on the mean content and variability in chemical composition, fatty acid (FA) profile and ensiling quality of maize silages, and discusses the major factors which cause these variations. In addition, the effect of the broad range in chemical composition of maize silages on the total tract digestibility of dietary nutrients, milk production and milk composition of dairy cows is quantified and discussed. Finally, the optimum inclusion level of maize silage in the ration of dairy cows for milk production and composition is reviewed. The data showed that the nutritive value of maize silages is highly variable and that most of this variation is caused by large differences in maturity at harvest. Maize silages ensiled at a very early stage (dry matter (DM) < 250 g kg(-1)) were particularly low in starch content and starch/neutral detergent fibre (NDF) ratio, and resulted in a lower DM intake (DMI), milk yield and milk protein content. The DMI, milk yield and milk protein content increased with advancing maturity, reaching an optimum level for maize silages ensiled at DM contents of 300-350 g kg(-1), and then declined slightly at further maturity beyond 350 g kg(-1). The increases in milk (R(2) = 0.599) and protein (R(2) = 0.605) yields with maturity of maize silages were positively related to the increase in starch/NDF ratio of the maize silages. On average, the inclusion of maize silage in grass silage-based diets improved the forage DMI by 2 kg d(-1), milk yield by 1.9 kg d(-1) and milk protein content by 1.2 g kg(-1). Further comparisons showed that, in terms of milk and milk constituent yields, the optimum grass/maize silage ratio depends on the quality of both the grass and maize silages. Replacement of grass silage with maize silage in the ration, as well as an increasing maturity of the maize silages, altered the milk FA profile of the dairy cows, notably, the concentration of the cis-unsaturated FAs, C18:3n-3 and n-3/n-6 ratio decreased in milk fat. Despite variation in nutritive value, maize silage is rich in metabolizable energy and supports higher DMI and milk yield. Harvesting maize silages at a DM content between 300 and 350 g kg(-1) and feeding in combination with grass silage results in a higher milk yield of dairy cows.

The objectives were to compare in vitro gas and methane (CH4) production kinetics using rumen fluid as inoculum collected via the rumen cannulation (CAN) method and with the oral stomach tube (OST) method, and to test for interactions between the type of inoculum and the diet fed to the donor cows as well as with the substrate incubated. Four rumen-cannulated lactating Holstein-Friesian cows (364 ± 20 days in milk, 690 ± 37 kg of bodyweight, 22.0 ± 6.0 kg of milk/day; mean ± SD) were blocked in pairs balanced over treatment sequence in a 2 × 2 crossover design. Cows were fed a total mixed ration consisting of 40% maize silage, 30% grass silage, and 30% concentrate on dry matter (DM) basis, with or without dietary linseed oil (a difference of 23 g/kg DM in fat content between the two diets). Rumen fluid was collected using the CAN and the OST method from each cow at d 17 of each experimental period. Subsequently, a 48 h gas production (GP) experiment was performed in which rumen fluid from each donor cow × rumen fluid sampling method was incubated with three substrates, viz. amygold, lupine, and wheat. The pH of the rumen fluid obtained using the OST method was higher than that of the rumen fluid obtained using the CAN method, whereas the total VFA concentration was lower and the VFA molar proportions unaffected. Multiple diet × inoculum and substrate × inoculum interactions in in vitro GP and CH4 kinetic parameters were observed. Furthermore, several GP and CH4 kinetic parameters, including total GP, absolute, asymptotic, and relative CH4 production, and maximum CH4 production rate, were higher for the CAN method compared with the OST method. The opposite was observed for, amongst others, the switching characteristic of the CH4 production profile and the half time to reach maximum asymptotic GP of the insoluble fraction. In conclusion, rumen fluid obtained using the OST sampling technique differs from that obtained using the CAN method, resulting in differences in in vitro gas and CH4 production profiles between both methods. The multiple interactions indicate that the rumen fluid sampling method can affect the in vitro GP and CH4 kinetics found for diet and for substrate. The results of this study therefore do not support the OST method as a feasible alternative to the CAN method in dairy cattle to examine in vitro gas and CH4 production.

The aim of this study was to evaluate if the in vivo digestibility and intake differences, observed in previous studies, between Ile-de-France (IF) and Churra-da-Terra-Quente (CTQ) sheep breeds, were due to rumen environment and degradability differences. The intake, digestibility, rumen environment and degradability and urinary allantoin-nitrogen excretion were evaluated in 8 adult cannulated ewes (4 CTQ and 4 IF ewes). The animals were fed ad libitum hay – with and without a soybean meal supplementation (150 g/kg ingested hay, dry matter basis). The organic matter intake per kg of body weight was higher (P 0.05), whether the breeds where fed hay or hay supplemented with soybean meal. The volatile fatty acid concentrations in the rumen were similar (P > 0.05) for both genotypes. There was no breed effect (P > 0.05) on the rumen protozoa population, although supplementation increased its number (P 0.05) on rumen in sacco degradation results. Thus, the effective rumen degradation was lower in the CTQ breed, when its inherit lower outflow rate was used to calculate it. This study suggests that the native CTQ breed and the IF breed exhibit similar rumen conditions for the microbial degradation of fibrous feeds. Thus the higher intake and lower digestibility of the CTQ breed can only result from its inherit faster flow through the gastrointestinal tract

The digestive capacity of the Portuguese native breed of Barrosão cattle and the Holstein–Friesian breed was measured when fed meadow hay (72–74 g CP and 641–671 g NDF/kg dry matter), offered either alone or supplemented with soya bean meal (150 g/kg dry matter), at maintenance level. Four mature cows of each breed were used. Average initial live weight (LW) was 457 and 635 kg for the Barrosão and the Holstein–Friesian cows respectively. The organic matter digestibility (OMD) of the meadow hay was higher in Holstein–Friesian than in Barrosão cows (p 0.05). The results obtained in this study suggest a higher ability to digest fibre in the large dairy breed than in the small native breed. This suggestion is also supported by previous findings with sheep breeds largely differing in mature live weight.

This study investigated the effect of chilling and freezing (for 24 h) canine feces on in vitro gas production kinetics and fermentation end product profiles from carbohydrate-rich (in vitro run 1) and protein-rich (in vitro run 2) substrates. Feces were collected from 3 adult retriever-type dogs fed a canned diet for at least 2 wk. Each fecal sample was divided into 3 portions: 1 portion was used immediately as an inoculum (fresh) and the other 2 portions were used after either chilling to 5°C for 30 min and storage in crushed ice for 23.5 h (chilling) or freezing to -20°C for 30 min and storage in a prefrozen (-20°C) container for 23.5 h (freezing). The medium solution for run 1 contained N whereas that for run 2 was N free. Substrates included fructooligosaccharide (FOS), sugar beet pulp, and wheat middlings in run 1 and soybean meal, poultry meat meal, and feather meal in run 2. Gas production kinetics were calculated from cumulative gas production data measured for 72 h. After incubation, fermentation liquids were analyzed for short-chain fatty acids, NH3, and aromatic compounds. For both in vitro runs, chilling feces did not affect gas production kinetics and end product profiles of substrates compared with inocula from fresh feces. Freezing feces decreased the maximum rate of gas production in phase 2 for FOS (P

To gain knowledge on the precision of an in vitro method for characterisation of the fermentability of dietary fibres, this study aimed to evaluate the repeatability and reproducibility of such a method. Substrates used were citrus pectin (CP), fructo-oligosaccharides (FOS), guar gum (GG), sugar beet pulp (SBP) and wheat middlings (WM). Each substrate was incubated with faecal inoculum from five cats with three replicates for each substrate–cat combination. Gas production was measured continuously during the 48 h incubation and SCFA and organic matter disappearance (only SBP and WM) were determined after incubation. Four consecutive runs were performed. The within-run variability (repeatability) was generally lower for the more simple and pure substrates (CP, FOS, GG) than for the more complex substrates containing mixtures of fibres (SBP, WM). Replicates showed high variability, in particular for SCFA profiles and parameters of gas production kinetics. The between-run CV (reproducibility) for the measured parameters were, in general, below 10 % for CP, FOS and GG and higher values were obtained for SBP and WM. It is concluded that for precise dietary fibre characterisation, the number of replicates should be multiple and adjusted according to the variability of the parameters of interest and the complexity of fibres. The method yielded reproducible results with some variation in absolute values obtained, which may have an impact on the significance level of the differences among substrates.

Lignin inhibitory effects within the cell wall structure constitute a serious drawback in maximizing the utilization of fibrous feedstuffs in animal feeding. Therefore treatments that promote efficient delignification of these materials must be applied. This study evaluated the potential of white-rot fungi to upgrade the nutritive value of cowpea stover for rabbit feeding.There was an increase in the crude protein content of all substrates as a result of fungi treatments, reaching a net gain of 13% for Pleurotus citrinopileatus incubation. Overall, net losses of dry and organic matter occurred during fungi treatments. Although the fiber content remained identical, higher consumption of cell wall contents was measured for P. citrinopileatus incubation (between 40 and 45%). The incubation period did not influence lignin degradation for any of the fungi treatments. Differences within the fungal degradation mechanisms indicate that P. citrinopileatus treatment was most effective, enhancing in vitro organic matter digestibility by around 30% compared with the control.Treatment of cowpea stover with P. citrinopileatus led to an efficient delignification process which resulted in higher in vitro organic matter digestibility, showing its potential in the nutritional valorization of this feedstuff. © 2017 Society of Chemical Industry.

The aim of this study was optimizing Ceriporiopsis subvermispora and Lentinula edodes pre-treatment of wheat straw and wood chips by adding urea, manganese and linoleic acid. Optimization was defined as more lignin degradation and an increase in in vitro gas production (IVGP), which is a model for rumen degradation, in comparison to fungal treatment without additives. First urea, manganese and linoleic acid were added separately to C. subvermispora or L. edodes treatment of wheat straw and wood chips. Only manganese and linoleic acid addition improved lignin degradation and IVGP compared to the same treatment without additives. Mn (150 μg/g wheat straw) influenced C . subvermispora treatment most. A combination of manganese and linoleic acid was also applied since both act on manganese peroxidase. This combination did indeed increase lignin degradation in wheat straw by C . subvermispora , but IVGP was not changed. None of the additions had a significant effect on the other fungus–substrate combinations tested here.