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In Vitro Digestibility in Animal Nutritional Studies
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In Vitro Digestibility in Animal Nutritional Studies

A special issue of Animals (ISSN 2076-2615). This special issue belongs to the section "Animal Nutrition".

Deadline for manuscript submissions: closed (28 February 2020) | Viewed by 79029

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editor

Dr. Pier Giorgio Peiretti

E-Mail Website1 Website2
Guest Editor
Institute of Sciences of Food Production, National Research Council, 10095 Grugliasco, Italy
Interests: animal nutrition; feed digestibility; food of animal origin
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The use of animals in research elicits a diverse range of attitudes and emotions, with some people demanding the abolition of research on animals and others expressing strong support. Typically, opponents of animal research cite animal welfare and suffering, as well as the uselessness of digestibility trials. In vitro techniques for feed evaluation are important methodologies for studying the physiology of certain segments of the digestive tract and the fermentative and digestive characteristics of feed.

Given the above, the trend is to prefer the use of in vitro enzymatic analysis over in vivo studies, which are more costly, laborious, and require animals anyway. Different closed-system fermentation apparatuses have been used in digestibility studies in ruminants and monogastric and companion animals. The incubators developed for multiple analyses of feeds have reduced labor demands and improved precision compared to traditional in vitro methods, which are time-consuming and imprecise. Furthermore, they could offer an alternative system to traditional in vivo methods, but further studies are needed to fully assess the potential of different methods and apparatuses in animal nutritional studies.

Original manuscripts, including reviews that address any aspects of in vitro digestibility in animal nutritional studies, are invited for this Special Issue.

Dr. Pier Giorgio Peiretti
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Animals is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • digestibility techniques
  • gas production
  • degradability
  • fermentative characteristics
  • digestive process
  • enzyme
  • DaisyII incubator
  • rumen liquor
  • gastric digestion

Published Papers (23 papers)

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Editorial

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6 pages, 164 KiB  
Editorial
Introduction to the Special Issue: In Vitro Digestibility in Animal Nutritional Studies
by Pier Giorgio Peiretti
Animals 2020, 10(6), 929; https://doi.org/10.3390/ani10060929 - 27 May 2020
Cited by 4 | Viewed by 1711
Abstract
The use of animals in research elicits a diverse range of attitudes and emotions, with some people demanding the abolition of research on animals and others expressing strong support[...] Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)

Research

Jump to: Editorial, Review, Other

18 pages, 1484 KiB  
Article
Application of Meta-Analysis and Machine Learning Methods to the Prediction of Methane Production from In Vitro Mixed Ruminal Micro-Organism Fermentation
by Jennifer L. Ellis, Héctor Alaiz-Moretón, Alberto Navarro-Villa, Emma J. McGeough, Peter Purcell, Christopher D. Powell, Padraig O’Kiely, James France and Secundino López
Animals 2020, 10(4), 720; https://doi.org/10.3390/ani10040720 - 21 Apr 2020
Cited by 7 | Viewed by 2763
Abstract
In vitro gas production systems are utilized to screen feed ingredients for inclusion in ruminant diets. However, not all in vitro systems are set up to measure methane (CH4) production, nor do all publications report in vitro CH4. Therefore, [...] Read more.
In vitro gas production systems are utilized to screen feed ingredients for inclusion in ruminant diets. However, not all in vitro systems are set up to measure methane (CH4) production, nor do all publications report in vitro CH4. Therefore, the objective of this study was to develop models to predict in vitro CH4 production from total gas and volatile fatty acid (VFA) production data and to identify the major drivers of CH4 production in these systems. Meta-analysis and machine learning (ML) methodologies were applied to a database of 354 data points from 11 studies to predict CH4 production from total gas production, apparent DM digestibility (DMD), final pH, feed type (forage or concentrate), and acetate, propionate, butyrate and valerate production. Model evaluation was performed on an internal dataset of 107 data points. Meta-analysis results indicate that equations containing DMD, total VFA production, propionate, feed type and valerate resulted in best predictability of CH4 on the internal evaluation dataset. The ML models far exceeded the predictability achieved using meta-analysis, but further evaluation on an external database would be required to assess generalization ability on unrelated data. Between the ML methodologies assessed, artificial neural networks and support vector regression resulted in very similar predictability, but differed in fitting, as assessed by behaviour analysis. The models developed can be utilized to estimate CH4 emissions in vitro. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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11 pages, 887 KiB  
Article
The Role of Condensed Tannins in the In Vitro Rumen Fermentation Kinetics in Ruminant Species: Feeding Type Involved?
by Ives C. S. Bueno, Roberta A. Brandi, Gisele M. Fagundes, Gabriela Benetel and James Pierre Muir
Animals 2020, 10(4), 635; https://doi.org/10.3390/ani10040635 - 07 Apr 2020
Cited by 16 | Viewed by 2965
Abstract
Animal feeding behavior and diet composition determine rumen fermentation responses and its microbial characteristics. This study aimed to evaluate the rumen fermentation kinetics of domestic ruminants feeding diets with or without condensed tannins (CT). Holstein dairy cows, Nelore beef cattle, Mediterranean water buffalo, [...] Read more.
Animal feeding behavior and diet composition determine rumen fermentation responses and its microbial characteristics. This study aimed to evaluate the rumen fermentation kinetics of domestic ruminants feeding diets with or without condensed tannins (CT). Holstein dairy cows, Nelore beef cattle, Mediterranean water buffalo, Santa Inês sheep and Saanen goats were used as inoculum donors (three animals of each species). The substrates were maize silage (Zea mays), fresh elephant grass (Pennisetum purpureum), Tifton-85 hay (Cynodon spp.) and fresh alfalfa (Medicago sativa). Acacia (Acacia molissima) extract was used as the external CT source. The in vitro semi-automated gas production technique was used to assess the fermentation kinetics. The experimental design was completely randomized with five inoculum sources (animal species), four substrates (feeds) and two treatments (with or without extract). The inclusion of CT caused more severe effects in grazing ruminants than selector ruminants. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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15 pages, 1165 KiB  
Article
Rumen Methanogenesis, Rumen Fermentation, and Microbial Community Response to Nitroethane, 2-Nitroethanol, and 2-Nitro-1-Propanol: An In Vitro Study
by Zhenwei Zhang, Yanlu Wang, Xuemeng Si, Zhijun Cao, Shengli Li and Hongjian Yang
Animals 2020, 10(3), 479; https://doi.org/10.3390/ani10030479 - 13 Mar 2020
Cited by 3 | Viewed by 2621
Abstract
Nitroethane (NE), 2-nitroethanol (NEOH), and 2-nitro-1-propanol (NPOH) were comparatively examined to determine their inhibitory actions on rumen fermentation and methanogenesis in vitro. Fermentation characteristics, CH4 and total gas production, and coenzyme contents were determined at 6, 12, 24, 48, and 72 h [...] Read more.
Nitroethane (NE), 2-nitroethanol (NEOH), and 2-nitro-1-propanol (NPOH) were comparatively examined to determine their inhibitory actions on rumen fermentation and methanogenesis in vitro. Fermentation characteristics, CH4 and total gas production, and coenzyme contents were determined at 6, 12, 24, 48, and 72 h incubation time, and the populations of ruminal microbiota were analyzed by real-time PCR at 72 h incubation time. The addition of NE, NEOH, and NPOH slowed down in vitro rumen fermentation and reduced the proportion of molar CH4 by 96.7%, 96.7%, and 41.7%, respectively (p < 0.01). The content of coenzymes F420 and F430 and the relative expression of the mcrA gene declined with the supplementation of NE, NEOH, and NPOH in comparison with the control (p < 0.01). The addition of NE, NEOH, and NPOH decreased total volatile fatty acids (VFAs) and acetate (p < 0.05), but had no effect on propionate concentration (p > 0.05). Real-time PCR results showed that the relative abundance of total methanogens, Methanobacteriales, Methanococcales, and Fibrobacter succinogenes were reduced by NE, NEOH, and NPOH (p < 0.05). In addition, the nitro-degradation rates in culture fluids were ranked as NEOH (−0.088) > NE (−0.069) > NPOH (−0.054). In brief, the results firstly provided evidence that NE, NEOH, and NPOH were able to decrease methanogen abundance and dramatically decrease mcrA gene expression and coenzyme F420 and F430 contents with different magnitudes to reduce ruminal CH4 production. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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19 pages, 977 KiB  
Article
Models Based on the Mitscherlich Equation for Describing Typical and Atypical Gas Production Profiles Obtained from In Vitro Digestibility Studies Using Equine Faecal Inoculum
by Christopher D. Powell, Mewa S. Dhanoa, Anna Garber, Jo-Anne M. D. Murray, Secundino López, Jennifer L. Ellis and James France
Animals 2020, 10(2), 308; https://doi.org/10.3390/ani10020308 - 17 Feb 2020
Cited by 6 | Viewed by 2959
Abstract
Two models are proposed to describe atypical biphasic gas production profiles obtained from in vitro digestibility studies. The models are extensions of the standard Mitscherlich equation, comprising either two Mitscherlich terms or one Mitscherlich and one linear term. Two models that describe typical [...] Read more.
Two models are proposed to describe atypical biphasic gas production profiles obtained from in vitro digestibility studies. The models are extensions of the standard Mitscherlich equation, comprising either two Mitscherlich terms or one Mitscherlich and one linear term. Two models that describe typical monophasic gas production curves, the standard Mitscherlich and the France model [a generalised Mitscherlich (root-t) equation], were assessed for comparison. Models were fitted to 25 gas production profiles resulting from incubating feedstuffs with faecal inocula from equines. Seventeen profiles displayed atypical biphasic patterns while the other eight displayed typical monophasic patterns. Models were evaluated using statistical measures of goodness-of-fit and by analysis of residuals. Good agreement was found between observed atypical profiles values and fitted values obtained with the two biphasic models, and both can revert to a simple Mitscherlich allowing them to describe typical monophasic profiles. The models contain kinetic fermentation parameters that can be used in conjunction with substrate degradability information and digesta passage rate to calculate extent of substrate degradation in the rumen or hindgut. Thus, models link the in vitro gas production technique to nutrient supply in the animal by providing information relating to digestion and nutritive value of feedstuffs. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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14 pages, 861 KiB  
Article
Fermentation Pattern of Several Carbohydrate Sources Incubated in An in Vitro Semicontinuous System with Inocula From Ruminants Given Either Forage or Concentrate-Based Diets
by Zahia Amanzougarene, Susana Yuste and Manuel Fondevila
Animals 2020, 10(2), 261; https://doi.org/10.3390/ani10020261 - 06 Feb 2020
Cited by 3 | Viewed by 2156
Abstract
The fermentation pattern of several carbohydrate sources and their interaction with the nature of microbial inoculum was studied. Barley (B), maize (M), sorghum, (S), sugarbeet pulp (BP), citrus pulp (CP) and wheat bran (WB) were tested in an in vitro semicontinuous system maintaining [...] Read more.
The fermentation pattern of several carbohydrate sources and their interaction with the nature of microbial inoculum was studied. Barley (B), maize (M), sorghum, (S), sugarbeet pulp (BP), citrus pulp (CP) and wheat bran (WB) were tested in an in vitro semicontinuous system maintaining poorly buffered conditions from 0 to 6 h, and being gradually buffered to 6.5 from 8 to 24 h to simulate the rumen pH pattern. Rumen fluid inoculum was obtained from lambs fed with either concentrate and barley straw (CI) or alfalfa hay (FI). The extent of fermentation was higher with CI than FI throughout the incubation (p < 0.05). Among the substrates, S, BP and M maintained the highest pH (p < 0.05), whereas CP recorded the lowest pH with both inocula. Similarly, CP recorded the highest gas volume throughout the incubation, followed by WB and B, and S recorded the lowest volume (p < 0.05). On average, the total volatile fatty acid (VFA), as well as lactic acid concentration, was higher with CP than in the other substrates (p < 0.05). The microbial structure was more affected by the animal donor of inoculum than by the substrate. The in vitro semicontinuous system allows for the study of the rumen environment acidification and substrate microbial fermentation under intensive feeding conditions. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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11 pages, 230 KiB  
Article
Exploring Additive, Synergistic or Antagonistic Effects of Natural Plant Extracts on In Vitro Beef Feedlot-Type Rumen Microbial Fermentation Conditions
by Ignacio Fandiño, Gonzalo Fernandez-Turren, Alfred Ferret, Diego Moya, Lorena Castillejos and Sergio Calsamiglia
Animals 2020, 10(1), 173; https://doi.org/10.3390/ani10010173 - 20 Jan 2020
Cited by 7 | Viewed by 3781
Abstract
Six Essential oils (EO) (tea tree oil—TeTr, oregano oil—Ore, clove bud oil—Clo, thyme oil—Thy, rosemary oil—Ros, and sage oil—Sag) in Experiment 1; and different combinations of selected oils in Experiment 2, were evaluate at four doses in an in vitro microbial fermentation system [...] Read more.
Six Essential oils (EO) (tea tree oil—TeTr, oregano oil—Ore, clove bud oil—Clo, thyme oil—Thy, rosemary oil—Ros, and sage oil—Sag) in Experiment 1; and different combinations of selected oils in Experiment 2, were evaluate at four doses in an in vitro microbial fermentation system using ruminal fluid from beef cattle fed a 10:90 straw: Concentrate diet. In Experiment 1, TeTr, Ore, Clo and Thy improved rumen fermentation profile in a direction consistent with better feed utilization. In Experiment 2, TeTr mixed with Thy, Ore, Thy + Ore or Clo at 200 and 400 mg/L increased the molar proportion of propionate and decreased that of acetate, and the acetate to propionate ratio. However, the size of the effect was similar to that obtained with TeTr alone, suggesting that effects were not additive. When Thy, Ore or Thy + Ore where mixed with Clo, most effects on rumen fermentation profile disappeared, suggesting an antagonistic interaction of Clo with Thy and Ore. Results do not support the hypothesis of additivity among the EO tested, and antagonistic effects of Clo mixed with Thy or Ore were demonstrated at least in a low pH, beef-type fermentation conditions. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
16 pages, 2224 KiB  
Article
Combining Orchardgrass and Alfalfa: Effects of Forage Ratios on In Vitro Rumen Degradation and Fermentation Characteristics of Silage Compared with Hay
by Zhulin Xue, Nan Liu, Yanlu Wang, Hongjian Yang, Yuqi Wei, Philipe Moriel, Elizabeth Palmer and Yingjun Zhang
Animals 2020, 10(1), 59; https://doi.org/10.3390/ani10010059 - 28 Dec 2019
Cited by 15 | Viewed by 3397
Abstract
This study aimed to investigate the effects of different forage ratios of orchardgrass (Dactylis glomerata) and alfalfa (Medicago sativa) on in vitro rumen degradation and fermentation characteristics. Orchardgrass and alfalfa were harvested separately and prepared as hay and silage [...] Read more.
This study aimed to investigate the effects of different forage ratios of orchardgrass (Dactylis glomerata) and alfalfa (Medicago sativa) on in vitro rumen degradation and fermentation characteristics. Orchardgrass and alfalfa were harvested separately and prepared as hay and silage mixtures at ratios of 100:0, 75:25, 50:50, 25:75, and 0:100 (w/w on a dry matter basis) and anaerobically incubated for 48 h with rumen fluid obtained from lactating dairy cows. Fermented residues and cultured fluids were used to determine nutrient degradability, fermentation parameters, and associative effect indices. Increasing the proportion of alfalfa in hay and silage mixtures quadratically increased in vitro organic matter disappearance (IVOMD, up +5.14%) and marginally decreased in vitro neutral detergent fiber disappearance (NDFD, down −1.79%). Meanwhile, increasing the proportion of alfalfa accelerated the rumen fermentation process (e.g., gas production) and remarkably enhanced the growth of rumen microbes as indicated by microbial protein production (MCP, 13.4% increase). Increments of rumen degradability and methane production were more pronounced in silage mixtures than hay mixtures. In combination, a forage ratio of 50:50 for orchardgrass and alfalfa is recommended for both hay and silage in order to improve the feed use potential in ruminants. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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17 pages, 2813 KiB  
Article
In Vitro Evaluation of Different Dietary Methane Mitigation Strategies
by Juana C. Chagas, Mohammad Ramin and Sophie J. Krizsan
Animals 2019, 9(12), 1120; https://doi.org/10.3390/ani9121120 - 11 Dec 2019
Cited by 24 | Viewed by 5527
Abstract
We assessed and ranked different dietary strategies for mitigating methane (CH4) emissions and other fermentation parameters, using an automated gas system in two in vitro experiments. In experiment 1, a wide range of dietary CH4 mitigation strategies was tested. In [...] Read more.
We assessed and ranked different dietary strategies for mitigating methane (CH4) emissions and other fermentation parameters, using an automated gas system in two in vitro experiments. In experiment 1, a wide range of dietary CH4 mitigation strategies was tested. In experiment 2, the two most promising CH4 inhibitory compounds from experiment 1 were tested in a dose-response study. In experiment 1, the chemical compounds 2-nitroethanol, nitrate, propynoic acid, p-coumaric acid, bromoform, and Asparagopsis taxiformis (AT) decreased predicted in vivo CH4 production (1.30, 21.3, 13.9, 24.2, 2.00, and 0.20 mL/g DM, respectively) compared with the control diet (38.7 mL/g DM). The 2-nitroethanol and AT treatments had lower molar proportions of acetate and higher molar proportions of propionate and butyrate compared with the control diet. In experiment 2, predicted in vivo CH4 production decreased curvilinearly, molar proportions of acetate decreased, and propionate and butyrate proportions increased curvilinearly with increased levels of AT and 2-nitroethanol. Thus 2-nitroethanol and AT were the most efficient strategies to reduce CH4 emissions in vitro, and AT inclusion additionally showed a strong dose-dependent CH4 mitigating effect, with the least impact on rumen fermentation parameters. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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13 pages, 598 KiB  
Article
In Vitro Digestibility, In Situ Degradability, Rumen Fermentation and N Metabolism of Camelina Co-Products for Beef Cattle Studied with a Dual Flow Continuous Culture System
by Hèctor Salas, Lorena Castillejos, Montserrat López-Suárez and Alfred Ferret
Animals 2019, 9(12), 1079; https://doi.org/10.3390/ani9121079 - 03 Dec 2019
Cited by 7 | Viewed by 3637
Abstract
Camelina meal (CM) and camelina expeller (CE) were compared with soybean meal (SM) and rapeseed meal (RM). Trial 1 consisted of a modified Tilley and Terry in vitro technique. Trial 2 was an in situ technique performed by incubating nylon bags within cannulated [...] Read more.
Camelina meal (CM) and camelina expeller (CE) were compared with soybean meal (SM) and rapeseed meal (RM). Trial 1 consisted of a modified Tilley and Terry in vitro technique. Trial 2 was an in situ technique performed by incubating nylon bags within cannulated cows. Trial 3 consisted in dual-flow continuous culture fermenters. In Trial 1, CM, CE and RM showed similar DM digestibility and OM digestibility, and SM was the most digestible ingredient (p < 0.05). Trial 2 showed that CE had the numerically highest DM degradability, but CP degradability was similar to RM. Camelina meal had a DM degradability similar to SM and RM and had an intermediate coefficient of CP degradability. In Trial 3, CE diet tended to present a higher true OM digestibility than SM diet (p = 0.06). Total volatile fatty acids (VFA) was higher in CE and CM diets than in SM diet (p = 0.009). Crude protein degradation tended to be higher (p = 0.07), and dietary nitrogen flow tended to be lower (p = 0.06) in CE diet than in CM diet. The efficiency of microbial protein synthesis was not affected by treatment (p > 0.05). In conclusion, CE and CM as protein sources differ in CP coefficient of degradability but their results were similar to RM. More differences were detected with regard to SM. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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19 pages, 503 KiB  
Article
Relations of Ruminal Fermentation Parameters and Microbial Matters to Odd- and Branched-Chain Fatty Acids in Rumen Fluid of Dairy Cows at Different Milk Stages
by Keyuan Liu, Yang Li, Guobin Luo, Hangshu Xin, Yonggen Zhang and Guangyu Li
Animals 2019, 9(12), 1019; https://doi.org/10.3390/ani9121019 - 22 Nov 2019
Cited by 9 | Viewed by 2540
Abstract
The purpose of this research was to evaluate whether relationships exist between odd- and branched-chain fatty acids (OBCFAs) originating from milk fat and the corresponding data of ruminal fermentation parameters, microbial populations, and base contents that were used to mark microbial protein in [...] Read more.
The purpose of this research was to evaluate whether relationships exist between odd- and branched-chain fatty acids (OBCFAs) originating from milk fat and the corresponding data of ruminal fermentation parameters, microbial populations, and base contents that were used to mark microbial protein in rumen. Nine lactating Holstein dairy cows with similar body weights and parity were selected in this study, and the samples of rumen and milk were collected at the early, middle, and late stages, respectively. The rumen and milk samples were collected over three consecutive days from each cow, and the ruminal and milk OBCFA profiles, ruminal fermentation parameters, bacterial populations, and base contents were measured. The results showed that the concentrations of OBCFAs, with the exception of C11:0 and C15:0, were significantly different between milk and rumen (p < 0.05). The concentrations of anteiso-fatty acids in milk were higher than those in rumen, and the contents of linear odd-chain fatty acids were higher than those of branched-chain fatty acids in both milk and rumen. Significant relationships that existed between the concentrations of C11:0, iso-C15:0, anteiso-C15:0, C15:0, and anteiso-C17:0 in rumen and milk (p < 0.05). The total OBCFA content in milk was positively related to the acetate molar proportion but negatively correlated with isoacid contents (p < 0.05). The populations of Ruminococcus albus, R. flavefacients, and Eubacterium ruminantium were significantly related to milk C13:0 contents (p < 0.05). The adenine/N ratio was negatively related to milk OBCFA content (p < 0.05) but positively associated with the iso-C15:0/iso-C17:0 ratio (p < 0.05). Milk OBCFAs were significantly correlated with ruminal fermentation parameters, ruminal bacterial populations, and base contents. Milk OBCFAs had the potential to predict microbial nitrogen flow, and the prediction equations for ruminal microbial nitrogen flow were established for OBCFAs in dairy milk. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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10 pages, 2303 KiB  
Article
Comparison of Faecal versus Rumen Inocula for the Estimation of NDF Digestibility
by Maria Chiaravalli, Luca Rapetti, Andrea Rota Graziosi, Gianluca Galassi, Gianni Matteo Crovetto and Stefania Colombini
Animals 2019, 9(11), 928; https://doi.org/10.3390/ani9110928 - 07 Nov 2019
Cited by 7 | Viewed by 3588
Abstract
Cow faeces have been investigated as alternative inoculum to replace rumen fluid to determine neutral detergent fibre (NDF) digestibility (NDFD). Aims of this study were to estimate: (1) the NDFD (48 h) of feed ingredients using a rumen inoculum in comparison with faecal [...] Read more.
Cow faeces have been investigated as alternative inoculum to replace rumen fluid to determine neutral detergent fibre (NDF) digestibility (NDFD). Aims of this study were to estimate: (1) the NDFD (48 h) of feed ingredients using a rumen inoculum in comparison with faecal inocula from cows fed diets with different forage basis; (2) the undigestible NDF (uNDF) at 240 and 360 h with ruminal fluid and faecal inocula from lactating cows fed two different diets. At 48 h incubation, the NDFD was affected both by feed and type of inoculum (p < 0.01) and by their interaction (p = 0.03). Overall, the mean NDFD was higher for rumen inoculum than for faecal inocula (585 vs. 389 g/kg NDF, p < 0.05), and faecal inoculum obtained from cows fed hay-based diets gave lower NDFD than those from cows fed maize silage (367 vs. 440 g/kg, p < 0.05). At long incubation times, the average uNDF was affected by substrate, inoculum and incubation time (p < 0.01), but not by their interactions. For each inoculum, significantly lower values were obtained at 360 than at 240 h. Regressions between uNDF with rumen and with the tested faecal inocula resulted in r2 ≥ 0.98. Despite the differences at 48 h, the uNDF showed that faecal inoculum could replace rumen fluid at longer incubation times. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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16 pages, 300 KiB  
Article
Rumen In Vitro Fermentation and In Situ Degradation Kinetics of Winter Forage Brassicas Crops
by José Daza, Daniel Benavides, Rubén Pulido, Oscar Balocchi, Annick Bertrand and Juan Keim
Animals 2019, 9(11), 904; https://doi.org/10.3390/ani9110904 - 01 Nov 2019
Cited by 10 | Viewed by 2829
Abstract
The aim of the present study was to evaluate the nutritional value, the rumen in vitro fermentation, and the in situ degradation of Brassica oleracea (L.) ssp. acephala (kales) and Brassica napus (L.) ssp. napobrassica (swedes) for winter use. Five varieties of each [...] Read more.
The aim of the present study was to evaluate the nutritional value, the rumen in vitro fermentation, and the in situ degradation of Brassica oleracea (L.) ssp. acephala (kales) and Brassica napus (L.) ssp. napobrassica (swedes) for winter use. Five varieties of each brassica were used in three field replicates and were randomized in a complete block nested design. All forage varieties were harvested at 210 days post-sowing to analyze the chemical composition, in vitro gas production, volatile fatty acid (VFA) production and in situ dry matter (DM) and crude protein (CP) degradability. Kales presented higher DM and neutral detergent fiber (NDF) content (p < 0.01), whereas swedes showed higher CP, metabolizable energy (ME), glucose, fructose, total sugars, NFC, and nonstructural carbohydrate (NSC) content (p < 0.01). The kale and swede varieties differed in their CP and sugar concentrations, whereas the kale varieties differed in their DM and raffinose content. The rates of gas production were higher for swedes than for kales (p < 0.01). No differences between the brassica species (p > 0.05) were observed in the total VFA production, whereas kales had a higher proportion of acetate and swedes had higher proportions of butyrate (p < 0.05). Only the swede varieties showed differences in VFA production (p < 0.05). The soluble fraction “a”, potential and effective in situ DM degradability were higher in swedes (p < 0.01), but kales presented greater DM and CP degradation rates. Differences were observed between brassica species in the chemical composition, degradation kinetics, and ruminal fermentation products, whereas differences among varieties within species were less frequent but need to be considered. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
19 pages, 263 KiB  
Article
Variability and Potential of Seaweeds as Ingredients of Ruminant Diets: An In Vitro Study
by Ana de la Moneda, Maria Dolores Carro, Martin R. Weisbjerg, Michael Y. Roleda, Vibeke Lind, Margarita Novoa-Garrido and Eduarda Molina-Alcaide
Animals 2019, 9(10), 851; https://doi.org/10.3390/ani9100851 - 22 Oct 2019
Cited by 30 | Viewed by 4279
Abstract
This study was designed to analyze the chemical composition and in vitro rumen fermentation of eight seaweed species (Brown: Alaria esculenta, Laminaria digitata, Pelvetia canaliculata, Saccharina latissima; Red: Mastocarpus stellatus, Palmaria palmata and Porphyra sp.; Green: Cladophora rupestris [...] Read more.
This study was designed to analyze the chemical composition and in vitro rumen fermentation of eight seaweed species (Brown: Alaria esculenta, Laminaria digitata, Pelvetia canaliculata, Saccharina latissima; Red: Mastocarpus stellatus, Palmaria palmata and Porphyra sp.; Green: Cladophora rupestris) collected in Norway during spring and autumn. Moreover, the in vitro ruminal fermentation of seventeen diets composed of 1:1 oat hay:concentrate, without (control diet) or including seaweeds was studied. The ash and N contents were greater (p < 0.001) in seaweeds collected during spring than in autumn, but autumn-seaweeds had greater total extractable polyphenols. Nitrogen in red and green seaweeds was greater than 2.20 and in brown seaweeds, it was lower than 1.92 g/kg DM. Degradability after 24 h of fermentation was greater in spring seaweeds than in autumn, with Palmaria palmata showing the greatest value and Pelvetia canaliculata the lowest. Seaweeds differed in their fermentation pattern, and autumn Alaria esculenta, Laminaria digitata, Saccharina latissima and Palmaria palmata were similar to high-starch feeds. The inclusion of seaweeds in the concentrate of a diet up to 200 g/kg concentrate produced only subtle effects on in vitro ruminal fermentation. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
14 pages, 388 KiB  
Article
Rumen Inoculum Collected from Cows at Slaughter or from a Continuous Fermenter and Preserved in Warm, Refrigerated, Chilled or Freeze-Dried Environments for In Vitro Tests
by Mauro Spanghero, Maria Chiaravalli, Stefania Colombini, Carla Fabro, Federico Froldi, Federico Mason, Maurizio Moschini, Chiara Sarnataro, Stefano Schiavon and Franco Tagliapietra
Animals 2019, 9(10), 815; https://doi.org/10.3390/ani9100815 - 16 Oct 2019
Cited by 21 | Viewed by 4326
Abstract
The utilization of animal donors of rumen fluid for laboratory experiments can raise ethical concerns, and alternatives to the collection of rumen fluids from live animals are urgently requested. The aim of this study was to compare the fresh rumen fluid (collected at [...] Read more.
The utilization of animal donors of rumen fluid for laboratory experiments can raise ethical concerns, and alternatives to the collection of rumen fluids from live animals are urgently requested. The aim of this study was to compare the fresh rumen fluid (collected at slaughter, W) with that obtained from a continuous fermenter (RCF) and three methods of rumen fluid preservation (refrigeration, R, chilling, C, and freeze-drying, FD). The fermentability of different inoculum was evaluated by three in vitro tests (neutral detergent fiber (NDF) and crude protein (CP) degradability and gas production, NDFd, RDP and GP, respectively) using six feeds as substrates. Despite the two types of inoculum differed in terms of metabolites and microbiota concentration, the differences in vitro fermentability between the two liquids were less pronounced than expected (−15 and 20% for NDFd and GP when the liquid of fermenter was used and no differences for RDP). Within each in vitro test, the data obtained from rumen and from fermenter liquids were highly correlated for the six feeds, as well as between W and R (r: 0.837–0.985; p < 0.01). The low fermentative capacity was found for C and, particularly, FD for liquids. RCF could be used to generate inoculum for in vitro purposes and short-term refrigeration is a valuable practice to manage inoculum. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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10 pages, 526 KiB  
Article
Effects of Gas Production Recording System and Pig Fecal Inoculum Volume on Kinetics and Variation of In Vitro Fermentation using Corn Distiller’s Dried Grains with Solubles and Soybean Hulls
by Jae-Cheol Jang, Zhikai Zeng, Gerald C. Shurson and Pedro E. Urriola
Animals 2019, 9(10), 773; https://doi.org/10.3390/ani9100773 - 09 Oct 2019
Cited by 12 | Viewed by 2590
Abstract
An experiment was conducted to investigate the effect of inoculum volume (IV), substrate quantity, and the use of a manual or automated gas production (GP) recording system for in vitro determinations of fermentation of corn distillers dried grains with solubles (cDDGS) and soybean [...] Read more.
An experiment was conducted to investigate the effect of inoculum volume (IV), substrate quantity, and the use of a manual or automated gas production (GP) recording system for in vitro determinations of fermentation of corn distillers dried grains with solubles (cDDGS) and soybean hulls (SBH). A 2 × 2 × 2 factorial arrangement of treatments was used and included the factors of (1) ingredients (cDDGS or SBH), (2) inoculum volume and substrate quantity (IV30 = 0.2 g substrate + 30 mL inoculum or IV75 = 0.5 g substrate + 75 mL inoculum), and (3) GP recording system (MRS = manual recording system or ARS = automated recording system). Feed ingredient samples were pre-treated with pepsin and pancreatin, and the hydrolyzed residues were subsequently incubated with fresh pig feces in a buffered mineral solution. The GP recording was monitored for 72 h, and the kinetics were estimated by fitting data using an exponential model. Compared with SBH, cDDGS yielded less (p < 0.01) maximal gas production (Gf), required more time (p < 0.02) to achieve half gas accumulation (T/2), and had less (p < 0.01) fractional rate of degradation (µ) and in vitro fermentability of dry matter (IVDMF). Using the ARS resulted in less IVDMF (p < 0.01) compared with MRS (79.0% vs. 81.2%, respectively). Interactions were observed between GP recording system and inoculum volume and substrate quantity for Gf (p < 0.04), µ (p < 0.01), and T/2 (p < 0.04) which implies that increasing inoculum volume and substrate quantity resulted in decreased Gf (332 mL/g from IV30 vs. 256 mL/g from IV75), µ (0.05 from IV30 vs. 0.04 from IV75), and T/2 (34 h for IV30 vs. 25 h for IV75) when recorded with ARS but not MRS. However, the recorded cumulative GP at 72 h was not influenced by the inoculum volume nor recording system. The precision of Gf (as measured by the coefficient of variation of Gf) tended to increase for IV30 compared with IV75 (p < 0.10), indicating that using larger inoculum volume and substrate quantity (IV75) reduced within batch variation in GP kinetics. Consequently, both systems showed comparable results in GP kinetics, but considering convenience and achievement of consistency, 75 mL of inoculum volume with 0.5 g substrate is recommended for ARS. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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12 pages, 286 KiB  
Article
Comparative Grain Yield, Straw Yield, Chemical Composition, Carbohydrate and Protein Fractions, In Vitro Digestibility and Rumen Degradability of Four Common Vetch Varieties Grown on the Qinghai-Tibetan Plateau
by Yafeng Huang, Fangfang Zhou and Zhibiao Nan
Animals 2019, 9(8), 505; https://doi.org/10.3390/ani9080505 - 31 Jul 2019
Cited by 8 | Viewed by 2448
Abstract
Four varieties of common vetch, including three improved varieties (Lanjian No. 1, Lanjian No. 2, and Lanjian No. 3) and one local variety (333A), were evaluated for varietal variations in grain yield, straw yield and straw quality attributes on the Qinghai-Tibetan Plateau. Crops [...] Read more.
Four varieties of common vetch, including three improved varieties (Lanjian No. 1, Lanjian No. 2, and Lanjian No. 3) and one local variety (333A), were evaluated for varietal variations in grain yield, straw yield and straw quality attributes on the Qinghai-Tibetan Plateau. Crops were harvested at pod maturity to determine grain yield, straw yield, harvest index, and potential utility index (PUI). Straw quality was determined by measuring chemical composition, carbohydrate and protein fractions, in vitro gas production and in situ ruminal degradability. Results showed a significant effect (p < 0.01) of variety on the grain yield [875.2–1255 kg dry matter (DM)/ha], straw yield (3154–5556 kg DM/ha), harvest index (15.6–28.7%) and PUI (53.3–63.2%). Variety also had a significant effect on chemical composition, carbohydrate and protein fractions (p < 0.05) except non-structural carbohydrates and rapidly degradable sugars. Significant differences (p < 0.05) were observed among the varieties in potential gas production [188–234 mL/g DM], in vitro organic matter (OM) digestibility (43.7–54.2% of OM), and metabolizable energy (6.40–7.92 MJ/kg DM) of straw. Significant differences (p < 0.001) were also observed among the varieties in rapidly degradable DM fraction and effective DM degradability of straw; however, no difference was observed in other DM degradation parameters and neutral detergent fiber degradation parameters. In conclusion, based on straw yield and quality, Lanjian No. 1 has the greatest potential among the tested varieties as a crop for supplementing ruminant diets for smallholder farmers on the Qinghai-Tibetan plateau. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
12 pages, 442 KiB  
Communication
Ruminal In Vitro Protein Degradation and Apparent Digestibility of Energy and Nutrients in Sheep Fed Native or Ensiled + Toasted Pea (Pisum sativum) Grains
by Martin Bachmann, Christian Kuhnitzsch, Paul Okon, Siriwan D. Martens, Jörg M. Greef, Olaf Steinhöfel and Annette Zeyner
Animals 2019, 9(7), 401; https://doi.org/10.3390/ani9070401 - 01 Jul 2019
Cited by 8 | Viewed by 3297
Abstract
Pea grains may partially replace soybean or rapeseed meals and cereals in ruminant diets, but substitution by unprocessed peas is limited by high ruminal protein solubility. The effect of combined ensiling and toasting of peas using a mobile toaster (100 kg/h throughput rate, [...] Read more.
Pea grains may partially replace soybean or rapeseed meals and cereals in ruminant diets, but substitution by unprocessed peas is limited by high ruminal protein solubility. The effect of combined ensiling and toasting of peas using a mobile toaster (100 kg/h throughput rate, 180 to 190 °C supplied air temperature) on rumen-undegraded protein (RUP) was tested in vitro using the Streptomyces griseus protease test. The effects of ensiling plus toasting on apparent digestibility of organic matter (OM), gross energy (GE), and proximate nutrients were examined in a digestion trial. Concentrations of metabolizable energy (ME) and net energy lactation (NEL) were calculated. Native peas had 38 g RUP/kg dry matter (DM), which was 20% of crude protein (CP). Rumen-undegraded protein increased three-fold after ensiling plus toasting (p < 0.001). Acid detergent insoluble protein increased five-fold. Apparent digestibility was 0.94 (OM), 0.90 (CP), and above 0.99 (nitrogen-free extract, starch, and sugars) and was not altered by the treatment. The ME (13.9 MJ/kg DM) or the NEL (8.9 MJ/kg DM) concentration was similar in native and ensiled plus toasted peas. This technique can easily be applied on farms and may increase RUP. However, it needs to be clarified under which conditions pea protein will be damaged. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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13 pages, 257 KiB  
Article
Comparative Grain Chemical Composition, Ruminal Degradation In Vivo, and Intestinal Digestibility In Vitro of Vicia Sativa L. Varieties Grown on the Tibetan Plateau
by Yafeng Huang, Rui Li, Jeffrey A. Coulter, Zhixin Zhang and Zhibiao Nan
Animals 2019, 9(5), 212; https://doi.org/10.3390/ani9050212 - 02 May 2019
Cited by 11 | Viewed by 2288
Abstract
Four varieties of common vetch, three improved varieties and one local variety, were evaluated for grain chemical composition, rumen protein degradability, and intestinal protein digestibility over two cropping years on the Tibetan Plateau. This study also examined correlations of grain chemical composition with [...] Read more.
Four varieties of common vetch, three improved varieties and one local variety, were evaluated for grain chemical composition, rumen protein degradability, and intestinal protein digestibility over two cropping years on the Tibetan Plateau. This study also examined correlations of grain chemical composition with rumen degradability parameters of grain protein and with intestinal digestibility of grain protein. Results of this study showed that grain quality attributes varied (p < 0.05) among varieties and cropping years. Significant intra-species variation was observed for concentrations (g/kg dry matter) of crude protein (CP; range = 347–374), ether extract (range = 15.8–19.6), neutral detergent fiber (aNDF; range = 201–237), acid detergent fiber (range = 58.2–71.6), ash (range = 27.6–31.0), effective CP degradability (EDCP; range = 732–801 g/kg CP), and intestinally absorbable digestible protein (IADP; range = 136–208 g/kg CP). The relationship between grain chemical composition and IADP was best described by the linear regression equation IADP = –0.828CP + 8.80ash + 0.635aNDF + 70.2 (R2 = 0.891), indicating that chemical analysis offers a quick and reliable method for IADP of common vetch grain. In terms of EDCP and IADP of grain, common vetch varieties, Lanjian No.2 and Lanjian No. 3, have the greatest potential among varieties tested for supplementing ruminant diets when grown on the Tibetan Plateau. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
14 pages, 589 KiB  
Article
Methane Production of Fresh Sainfoin, with or without PEG, and Fresh Alfalfa at Different Stages of Maturity is Similar but the Fermentation End Products Vary
by Pablo José Rufino-Moya, Mireia Blanco, Juan Ramón Bertolín and Margalida Joy
Animals 2019, 9(5), 197; https://doi.org/10.3390/ani9050197 - 26 Apr 2019
Cited by 11 | Viewed by 2977
Abstract
Alfalfa and sainfoin are high-quality forages with different condensed tannins (CT) content, which can be affected by the stage of maturity. To study the effects of CT on fermentation parameters, three substrates (alfalfa, sainfoin, and sainfoin+PEG) at three stages of maturity were in [...] Read more.
Alfalfa and sainfoin are high-quality forages with different condensed tannins (CT) content, which can be affected by the stage of maturity. To study the effects of CT on fermentation parameters, three substrates (alfalfa, sainfoin, and sainfoin+PEG) at three stages of maturity were in vitro incubated for 72 h. Sainfoin had greater total polyphenol and CT contents than alfalfa. As maturity advanced, CT contents in sainfoin decreased (p < 0.05), except for the protein-bound CT fraction (p > 0.05). The total gas and methane production was affected neither by the substrate nor by the stage of maturity (p > 0.05). Overall, sainfoin and sainfoin+PEG had greater in vitro organic matter degradability (IVOMD) than alfalfa (p < 0.05). Alfalfa and sainfoin+PEG presented higher ammonia content than sainfoin (p < 0.001). Total volatile fatty acid (VFA) production was only affected by the stage of maturity (p < 0.05), and the individual VFA proportions were affected by the substrate and the stage of maturity (p < 0.001). In conclusion, alfalfa and sainfoin only differed in the IVOMD and the fermentation end products. Moreover, CT reduced ammonia production and the ratio methane: VFA, but the IVOMD was reduced only in the vegetative stage. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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Review

Jump to: Editorial, Research, Other

24 pages, 946 KiB  
Review
In Vitro Techniques Using the DaisyII Incubator for the Assessment of Digestibility: A Review
by Sonia Tassone, Riccardo Fortina and Pier Giorgio Peiretti
Animals 2020, 10(5), 775; https://doi.org/10.3390/ani10050775 - 29 Apr 2020
Cited by 30 | Viewed by 6013
Abstract
This review summarises the use of the Ankom DaisyII incubator (ADII; Ankom Technology Corporation Fairport, NY, USA), as presented in studies on digestibility, and its extension to other species apart from ruminants, from its introduction until today. This technique has [...] Read more.
This review summarises the use of the Ankom DaisyII incubator (ADII; Ankom Technology Corporation Fairport, NY, USA), as presented in studies on digestibility, and its extension to other species apart from ruminants, from its introduction until today. This technique has been modified and adapted to allow for different types of investigations to be conducted. Researchers have studied and tested different procedures, and the main sources of variation have been found to be: the inoculum source, sample size, sample preparation, and bag type. In vitro digestibility methods, applied to the ADII incubator, have been reviewed, the precision and accuracy of the method using the ADII incubator have been dealt with, and comparisons with other methods have been made. Moreover, some hypotheses on the possible evolutions of this technology in non-ruminants, including pets, have been described. To date, there are no standardised protocols for the collection, storage, and transportation of rumen fluid or faeces. There is also still a need to standardise the procedures for washing the bags after digestion. Moreover, some performance metrics of the instrument (such as the reliability of the rotation mechanism of the jars) still require improvement. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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19 pages, 872 KiB  
Review
In Vitro Methods of Assessing Protein Quality for Poultry
by Dervan D.S.L. Bryan and Henry L. Classen
Animals 2020, 10(4), 551; https://doi.org/10.3390/ani10040551 - 25 Mar 2020
Cited by 20 | Viewed by 7055
Abstract
Protein quality assessment of feed ingredients for poultry is often achieved using in vitro or in vivo testing. In vivo methods can be expensive and time consuming. Protein quality can also be evaluated using less expensive and time consuming chemical methods, termed in [...] Read more.
Protein quality assessment of feed ingredients for poultry is often achieved using in vitro or in vivo testing. In vivo methods can be expensive and time consuming. Protein quality can also be evaluated using less expensive and time consuming chemical methods, termed in vitro. These techniques are used to improve the user’s efficiency when dealing with large sample numbers, and some mimic the physiological and chemical characteristics of the animal digestive system to which the ingredient will be fed. The pepsin digestibility test is the in vitro method of choice for quick evaluation of protein sample during quality control and in most research settings. Even though the pepsin digestibility test uses enzymes to liberate the amino acids from the protein, it does not mimic normal in vivo digestive conditions. The results obtained with this method may be misleading if the samples tested contain fats or carbohydrates which they often do. Multi-enzyme tests have been proposed to overcome the problem encountered when using the pepsin digestibility test. These tests use a combination of enzymes in one or multiple steps customized to simulate the digestive process of the animal. Multi enzyme assays can predict animal digestibility, but any inherent biological properties of the ingredients on the animal digestive tract will be lost. Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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Other

3 pages, 183 KiB  
Erratum
Erratum: Rufino-Moya, P.J., et al. Methane Production of Fresh Sainfoin, with or without PEG, and Fresh Alfalfa at Different Stages of Maturity is Similar, but the Fermentation End Products Vary. Animals 2019, 9, 197
by Pablo José Rufino-Moya, Mireia Blanco, Juan Ramón Bertolín and Margalida Joy
Animals 2019, 9(7), 421; https://doi.org/10.3390/ani9070421 - 05 Jul 2019
Cited by 1 | Viewed by 1623
Abstract
The authors wish to make the following correction to their paper [...] Full article
(This article belongs to the Special Issue In Vitro Digestibility in Animal Nutritional Studies)
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