1
|
Yergaliyev T, Künzel S, Hanauska A, Rees A, Wild KJ, Pétursdóttir ÁH, Gunnlaugsdóttir H, Reynolds CK, Humphries DJ, Rodehutscord M, Camarinha-Silva A. The effect of Asparagopsis taxiformis, Ascophyllum nodosum, and Fucus vesiculosus on ruminal methanogenesis and metagenomic functional profiles in vitro. Microbiol Spectr 2024:e0394223. [PMID: 39347544 DOI: 10.1128/spectrum.03942-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 07/08/2024] [Indexed: 10/01/2024] Open
Abstract
The ruminant-microorganism symbiosis is unique by providing high-quality food from fibrous materials but also contributes to the production of one of the most potent greenhouse gases-methane. Mitigating methanogenesis in ruminants has been a focus of interest in the past decades. One of the promising strategies to combat methane production is the use of feed supplements, such as seaweeds, that might mitigate methanogenesis via microbiome modulation and direct chemical inhibition. We conducted in vitro investigations of the effect of three seaweeds (Ascophyllum nodosum, Asparagopsis taxiformis, and Fucus vesiculosus) harvested at different locations (Iceland, Scotland, and Portugal) on methane production. We applied metataxonomics (16S rRNA gene amplicons) and metagenomics (shotgun) methods to uncover the interplay between the microbiome's taxonomical and functional states, methanogenesis rates, and seaweed supplementations. Methane concentration was reduced by A. nodosum and F. vesiculosus, both harvested in Scotland and A. taxiformis, with the greatest effect of the latter. A. taxiformis acted through the reduction of archaea-to-bacteria ratios but not eukaryotes-to-bacteria. Moreover, A. taxiformis application was accompanied by shifts in both taxonomic and functional profiles of the microbial communities, decreasing not only archaeal ratios but also abundances of methanogenesis-associated functions. Methanobrevibacter "SGMT" (M. smithii, M. gottschalkii, M. millerae or M. thaueri; high methane yield) to "RO" (M. ruminantium and M. olleyae; low methane yield) clades ratios were also decreased, indicating that A. taxiformis application favored Methanobrevibacter species that produce less methane. Most of the functions directly involved in methanogenesis were less abundant, while the abundances of the small subset of functions that participate in methane assimilation were increased. IMPORTANCE The application of A. taxiformis significantly reduced methane production in vitro. We showed that this reduction was linked to changes in microbial function profiles, the decline in the overall archaeal community counts, and shifts in ratios of Methanobrevibacter "SGMT" and "RO" clades. A. nodosum and F. vesiculosus, obtained from Scotland, also decreased methane concentration in the total gas, while the same seaweed species from Iceland did not.
Collapse
Affiliation(s)
- Timur Yergaliyev
- Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
- HoLMiR - Hohenheim Center for Livestock Microbiome Research, University of Hohenheim, Stuttgart, Germany
| | - Susanne Künzel
- Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
- HoLMiR - Hohenheim Center for Livestock Microbiome Research, University of Hohenheim, Stuttgart, Germany
| | - Anna Hanauska
- Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
| | - Antonia Rees
- Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
| | - Katharina J Wild
- Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
| | | | | | - Christopher K Reynolds
- School of Agriculture, Policy and Development, University of Reading, Reading, United Kingdom
| | - David J Humphries
- School of Agriculture, Policy and Development, University of Reading, Reading, United Kingdom
| | - Markus Rodehutscord
- Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
- HoLMiR - Hohenheim Center for Livestock Microbiome Research, University of Hohenheim, Stuttgart, Germany
| | - Amélia Camarinha-Silva
- Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
- HoLMiR - Hohenheim Center for Livestock Microbiome Research, University of Hohenheim, Stuttgart, Germany
| |
Collapse
|
2
|
Wang B, Ormston S, Płatosz N, Parker JK, Qin N, Humphries DJ, Pétursdóttir ÁH, Halmemies-Beauchet-Filleau A, Juniper DT, Stergiadis S. Effect of dietary protein source and Saccharina latissima on nutritional and safety characteristics of milk. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2024; 104:7355-7366. [PMID: 38661233 DOI: 10.1002/jsfa.13556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 04/11/2024] [Accepted: 04/20/2024] [Indexed: 04/26/2024]
Abstract
BACKGROUND Wheat distillers' grains (WDG) and seaweeds are recommended as alternative protein sources and enteric methane mitigators in dairy cow diets, respectively, but little is known about their impact on milk quality and safety. In the present study, 16 cows in four 4 × 4 Latin squares were fed isonitrogenous diets (50:50 forage:concentrate ratio), with rapeseed meal (RSM)-based or WDG-based concentrate (230 and 205 g kg-1 dry matter) and supplemented with or without Saccharina latissima. RESULTS Replacement of RSM with WDG enhanced milk nutritional profile by decreasing milk atherogenicity (P = 0.002) and thrombogenicity (P = 0.019) indices and the concentrations of the nutritionally undesirable saturated fatty acids - specifically, lauric (P = 0.045), myristic (P = 0.022) and palmitic (P = 0.007) acids. It also increased milk concentrations of the nutritionally beneficial vaccenic (P < 0.001), oleic (P = 0.030), linoleic (P < 0.001), rumenic (P < 0.001) and α-linolenic (P = 0.012) acids, and total monounsaturated (P = 0.044), polyunsaturated (P < 0.001) and n-6 (P < 0.001) fatty acids. Feeding Saccharina latissima at 35.7 g per cow per day did not affect the nutritionally relevant milk fatty acids or pose any risk on milk safety, as bromoform concentrations in milk were negligible and unaffected by the dietary treatments. However, it slightly reduced milk concentrations of pantothenate. CONCLUSION Feeding WDG to dairy cows improved milk fatty acid profiles, by increasing the concentrations of nutritionally beneficial fatty acids and reducing the concentration of nutritionally undesirable saturated fatty acids, while feeding seaweed slightly reduced pantothenate concentrations. However, when considering the current average milk intakes in the population, the milk compositional differences between treatments in this study appear relatively small to have an effect on human health. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Collapse
Affiliation(s)
- Bing Wang
- College of Animal Science and Technology, State Key Laboratory of Animal Nutrition and Feeding, China Agricultural University, Beijing, PR China
- School of Agriculture, Policy and Development, Department of Animal Sciences, University of Reading, Reading, UK
| | - Sabrina Ormston
- School of Agriculture, Policy and Development, Department of Animal Sciences, University of Reading, Reading, UK
| | - Natalia Płatosz
- School of Agriculture, Policy and Development, Department of Animal Sciences, University of Reading, Reading, UK
- Polish Academy of Sciences, Institute of Animal Reproduction and Food Research, Olsztyn, Poland
| | - Jane K Parker
- Department of Food and Nutritional Sciences, University of Reading, Reading, UK
| | - Nanbing Qin
- School of Agriculture, Policy and Development, Department of Animal Sciences, University of Reading, Reading, UK
| | - David J Humphries
- School of Agriculture, Policy and Development, Department of Animal Sciences, University of Reading, Reading, UK
| | | | | | - Darren T Juniper
- School of Agriculture, Policy and Development, Department of Animal Sciences, University of Reading, Reading, UK
| | - Sokratis Stergiadis
- School of Agriculture, Policy and Development, Department of Animal Sciences, University of Reading, Reading, UK
| |
Collapse
|
3
|
Li S, Sun Y, Guo T, Liu W, Tong X, Zhang Z, Sun J, Yang Y, Yang S, Li D, Min L. Sargassum mcclurei Mitigating Methane Emissions and Affecting Rumen Microbial Community in In Vitro Rumen Fermentation. Animals (Basel) 2024; 14:2057. [PMID: 39061518 PMCID: PMC11274217 DOI: 10.3390/ani14142057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Revised: 07/06/2024] [Accepted: 07/10/2024] [Indexed: 07/28/2024] Open
Abstract
Methane emissions from ruminants significantly contribute to greenhouse gases. This study explores the methane mitigation effect and mechanism of S. mcclurei through in vitro rumen fermentation, aiming to establish its potential as a feed additive. We investigated the effects of freeze-dried and dried S. mcclurei at supplementation levels of 2%, 5%, and 10% of dry matter on nutrient degradation, ruminal fermentation, methane inhibition, and microbial community structure in in vitro rumen fermentation. The freeze-dried S. mcclurei at 2% supplementation significantly reduced CH4 emissions by 18.85% and enhanced crude protein degradability. However, total VFA and acetate concentrations were lower in both treatments compared to the control. The microbial shifts included a decrease in Lachnospiraceae_NK3A20_group and Ruminococcus and an increase in Selenomonas, Succinivibrio, and Saccharofermentans, promoting propionate production. Additionally, a significant reduction in Methanomicrobium was observed, indicating direct methane mitigation. Freeze-dried S. mcclurei at a 2% supplementation level shows potential as an effective methane mitigation strategy with minimal impact on rumen fermentation, supported by detailed insights into microbial community changes.
Collapse
Affiliation(s)
- Shuai Li
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Ministry of Agriculture Key Laboratory of Animal Nutrition and Feed Science in South China, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; (S.L.); (Y.S.); (W.L.); (X.T.); (Z.Z.)
- Guangdong Provincial Key Laboratory of Animal Nutrition Regulation, College of Animal Science, South China Agricultural University, Guangzhou 510642, China;
| | - Yi Sun
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Ministry of Agriculture Key Laboratory of Animal Nutrition and Feed Science in South China, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; (S.L.); (Y.S.); (W.L.); (X.T.); (Z.Z.)
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), College of Life Science and Technology, Jinan University, Guangzhou 510632, China;
| | - Tongjun Guo
- Key Laboratory of Xinjiang feed biotechnology, Feed Research Institute, Xinjiang Academy of Animal Science, Urumqi 830000, China;
| | - Wenyou Liu
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Ministry of Agriculture Key Laboratory of Animal Nutrition and Feed Science in South China, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; (S.L.); (Y.S.); (W.L.); (X.T.); (Z.Z.)
- College of Life Sciences and Engineering, Foshan University, Foshan 528231, China;
| | - Xiong Tong
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Ministry of Agriculture Key Laboratory of Animal Nutrition and Feed Science in South China, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; (S.L.); (Y.S.); (W.L.); (X.T.); (Z.Z.)
| | - Zhifei Zhang
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Ministry of Agriculture Key Laboratory of Animal Nutrition and Feed Science in South China, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; (S.L.); (Y.S.); (W.L.); (X.T.); (Z.Z.)
| | - Jiajie Sun
- Guangdong Provincial Key Laboratory of Animal Nutrition Regulation, College of Animal Science, South China Agricultural University, Guangzhou 510642, China;
| | - Yufeng Yang
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), College of Life Science and Technology, Jinan University, Guangzhou 510632, China;
| | - Shuli Yang
- College of Life Sciences and Engineering, Foshan University, Foshan 528231, China;
| | - Dagang Li
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Ministry of Agriculture Key Laboratory of Animal Nutrition and Feed Science in South China, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; (S.L.); (Y.S.); (W.L.); (X.T.); (Z.Z.)
| | - Li Min
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Ministry of Agriculture Key Laboratory of Animal Nutrition and Feed Science in South China, Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; (S.L.); (Y.S.); (W.L.); (X.T.); (Z.Z.)
- Key Laboratory of Xinjiang feed biotechnology, Feed Research Institute, Xinjiang Academy of Animal Science, Urumqi 830000, China;
| |
Collapse
|
4
|
Mohapatra A, Trivedi S, Kolte AP, Tejpal CS, Elavarasan K, Vaswani S, Malik PK, Ravishankar CN, Bhatta R. Effect of Padina gymnospora biowaste inclusion on in vitro methane production, feed fermentation, and microbial diversity. Front Microbiol 2024; 15:1431131. [PMID: 39027100 PMCID: PMC11254855 DOI: 10.3389/fmicb.2024.1431131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Accepted: 06/19/2024] [Indexed: 07/20/2024] Open
Abstract
In vitro studies were undertaken aiming to study the methane (CH4) mitigation potential of biowaste (BW) of Padina gymnospora at the graded inclusion of 0% (C), 2% (A2), 5% (A5), and 10% (A10) of the diet composed of straw and concentrate in 40:60 ratio. The chemical composition analysis revealed that the BW contained higher crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and ether extract (EE) than the PF (fresh seaweed, P. gymnospora). The concentration of cinnamic acid, sinapic acid, kaempferol, fisetin p-coumaric acid, ellagic acid, and luteolin in BW was 1.5-6-folds less than the PF. Inclusion of BW decreased (P < 0.0001) CH4 production by 34%, 38%, and 45% in A2, A5, and A10 treatments, respectively. A decrease (P < 0.0001) of 7.5%-8% in dry matter (DM) and organic matter (OM) digestibility was also recorded with the BW supplementation. The BW inclusion also decreased the numbers of total (P = 0.007), Entodinomorphs (P = 0.011), and Holotrichs (P = 0.004) protozoa. Metagenome data revealed the dominance of Bacteroidetes, Proteobacteria, Firmicutes, Actinobacteria, and Fibrobacter microbial phyla. At the phylum level, Euryarchaeota dominated the archaeal community, whereas Methanobrevibacter was most abundant at the genus level. It can be concluded that the inclusion of BW in straw and concentrate based diet by affecting rumen fermentation, protozoal numbers, and compositional shift in the archaeal community significantly decreased CH4 production. Utilization of biowaste of P. gymnospora as a CH4 mitigating agent will ensure its efficient utilization rather than dumping, which shall cause environmental pollution and health hazards.
Collapse
Affiliation(s)
- Archit Mohapatra
- Indian Council of Agricultural Research (ICAR)-National Institute of Animal Nutrition and Physiology, Bengaluru, India
- School of Sciences, JAIN (Deemed-to-be-University), Bengaluru, India
| | - Shraddha Trivedi
- Indian Council of Agricultural Research (ICAR)-National Institute of Animal Nutrition and Physiology, Bengaluru, India
| | - Atul P. Kolte
- Indian Council of Agricultural Research (ICAR)-National Institute of Animal Nutrition and Physiology, Bengaluru, India
| | - Chaluvanahalli S. Tejpal
- Indian Council of Agricultural Research (ICAR)-Central Institute of Fisheries Technology, Kochi, India
| | - Krishnamoorthy Elavarasan
- Indian Council of Agricultural Research (ICAR)-Central Institute of Fisheries Technology, Kochi, India
| | - Shalini Vaswani
- Uttar Pradesh Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura, India
| | - Pradeep Kumar Malik
- Indian Council of Agricultural Research (ICAR)-National Institute of Animal Nutrition and Physiology, Bengaluru, India
| | | | | |
Collapse
|
5
|
Wanapat M, Prachumchai R, Dagaew G, Matra M, Phupaboon S, Sommai S, Suriyapha C. Potential use of seaweed as a dietary supplement to mitigate enteric methane emission in ruminants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 931:173015. [PMID: 38710388 DOI: 10.1016/j.scitotenv.2024.173015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 05/03/2024] [Accepted: 05/03/2024] [Indexed: 05/08/2024]
Abstract
Seaweeds or marine algae exhibit diverse morphologies, sizes, colors, and chemical compositions, encompassing various species, including red, green, and brown seaweeds. Several seaweeds have received increased research attention and application in animal feeding investigations, particularly in ruminant livestock, due to their higher yield and convenient harvestability at present. Recent endeavors encompassing both in vitro and in vivo experiments have indicated that many seaweeds, particularly red seaweed (Asparagopsis taxiformis and Asparagopsis armata), contain plant secondary compounds, such as halogenated compounds and phlorotannins, with the potential to reduce enteric ruminal methane (CH4) emissions by up to 99 % when integrated into ruminant diets. This review provides an encompassing exploration of the existing body of knowledge concerning seaweeds and their impact on rumen fermentation, the toxicity of ruminal microbes, the health of animals, animal performance, and enteric ruminal CH4 emissions in both in vitro and in vivo settings among ruminants. By attaining a deeper comprehension of the implications of seaweed supplementation on rumen fermentation, animal productivity, and ruminal CH4 emissions, we could lay the groundwork for devising innovative strategies. These strategies aim to simultaneously achieve environmental benefits, reduce greenhouse gas emissions, enhance animal efficiency, and develop aquaculture and seaweed production systems, ensuring a high-quality and consistent supply chain. Nevertheless, future research is essential to elucidate the extent of the effect and gain insight into the mode of action.
Collapse
Affiliation(s)
- Metha Wanapat
- Tropical Feed Resources Research and Development Center (TROFREC), Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Rittikeard Prachumchai
- Division of Animal Science, Faculty of Agricultural Technology, Rajamangala University of Technology Thanyaburi, Thanyaburi, Pathum Thani 12130, Thailand
| | - Gamonmas Dagaew
- Tropical Feed Resources Research and Development Center (TROFREC), Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Maharach Matra
- Tropical Feed Resources Research and Development Center (TROFREC), Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Srisan Phupaboon
- Tropical Feed Resources Research and Development Center (TROFREC), Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Sukruthai Sommai
- Tropical Feed Resources Research and Development Center (TROFREC), Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Chaichana Suriyapha
- Tropical Feed Resources Research and Development Center (TROFREC), Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand.
| |
Collapse
|
6
|
O’Hara E, Terry SA, Moote P, Beauchemin KA, McAllister TA, Abbott DW, Gruninger RJ. Comparative analysis of macroalgae supplementation on the rumen microbial community: Asparagopsis taxiformis inhibits major ruminal methanogenic, fibrolytic, and volatile fatty acid-producing microbes in vitro. Front Microbiol 2023; 14:1104667. [PMID: 37077241 PMCID: PMC10109387 DOI: 10.3389/fmicb.2023.1104667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 02/23/2023] [Indexed: 04/05/2023] Open
Abstract
Seaweeds have received a great deal of attention recently for their potential as methane-suppressing feed additives in ruminants. To date, Asparagopsis taxiformis has proven a potent enteric methane inhibitor, but it is a priority to identify local seaweed varieties that hold similar properties. It is essential that any methane inhibitor does not compromise the function of the rumen microbiome. In this study, we conducted an in vitro experiment using the RUSITEC system to evaluate the impact of three red seaweeds, A. taxiformis, Palmaria mollis, and Mazzaella japonica, on rumen prokaryotic communities. 16S rRNA sequencing showed that A. taxiformis had a profound effect on the microbiome, particularly on methanogens. Weighted Unifrac distances showed significant separation of A. taxiformis samples from the control and other seaweeds (p < 0.05). Neither P. mollis nor M. japonica had a substantial effect on the microbiome (p > 0.05). A. taxiformis reduced the abundance of all major archaeal species (p < 0.05), leading to an almost total disappearance of the methanogens. Prominent fiber-degrading and volatile fatty acid (VFA)-producing bacteria including Fibrobacter and Ruminococcus were also inhibited by A. taxiformis (p < 0.05), as were other genera involved in propionate production. The relative abundance of several other bacteria including Prevotella, Bifidobacterium, Succinivibrio, Ruminobacter, and unclassified Lachnospiraceae were increased by A. taxiformis suggesting that the rumen microbiome adapted to an initial perturbation. Our study provides baseline knowledge of microbial dynamics in response to seaweed feeding over an extended period and suggests that feeding A. taxiformis to cattle to reduce methane may directly, or indirectly, inhibit important fiber-degrading and VFA-producing bacteria.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Robert J. Gruninger
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada
| |
Collapse
|
7
|
Evaluation of Different Brown Seaweeds as Feed and Feed Additives Regarding Rumen Fermentation and Methane Mitigation. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8100504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
This study investigated the impacts of different brown seaweed species—Ascophyllum nodosum, Sargassum fulvellum, Ecklonia maxima, Lessonia flavicans, Lessonia nigrescens, and Laminaria japonica—on rumen fermentation and methane (CH4) mitigation. The current in vitro batch culture study for 24 h at 39 °C evaluated these species in two experimental designs: as feed additive and as feed. The control group for both experimental designs was composed of 500 mg of basal diet (50% grass hay/50% concentrate). For the feed additives experimental design, each seaweed species was evaluated when it was added at 20% of the basal diet, while as a feed, the inclusion level of each species was 20% to partially replace the concentrate in the basal diet as follows (50% hay/30% concentrate/20% seaweed). Chemical analyses showed that the seaweeds were characterized by a high fiber content and high amounts of minerals such as calcium, potassium, and phosphorus, while the protein content ranged within 7 and 13%. When they were applied as feed additives, they increased the production of volatile fatty acids, with L. japonica being the most effective; however, they failed to suppress CH4 production. In contrast, their inclusion as a feed in the basal diet led to a significant reduction (p < 0.05) in CH4, especially for E. maxima and L. japonica, by up to 18 and 21%, respectively, but this was associated with general inhibition of the rumen fermentation. Therefore, the tested seaweeds could be used as a source of minerals and as a feed additive to improve rumen fermentation, but without anti-methanogenic potential. Meanwhile, their inclusion as feed at 20% could reduce CH4 production with an adverse effect on fermentation. Thus, further trials are needed to identify the appropriate inclusion level to achieve effective CH4 reduction without any detrimental effects on rumen fermentation.
Collapse
|