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Contrasting rearing and finishing regimens on performance and methane emissions of Angus steers.
No full textBeef cattle production contributes to global warming mainly through the emission of methane (CH4) generated during
the normal process of feed digestion. Compensatory growth could provide a means to reduce CH4 emissions, since feed
efficiency improves during refeeding and an increase in feed digestibility could explain this improvement. Steers are
commonly fattened on pasture or feedlot, so the aim of the experiment was to evaluate the effect of dietary restriction
in Angus steers on DM digestibility (DMD) and CH4 emission under two contrasting refeeding diets. Eighty steers
with an average live weight (LW) of 444±39 kg and age of 18±1 months, were blocked, and randomly assigned to 1
of 4 treatments, in a 2×2 factorial arrangement: severity of dietary restriction (moderate vs mild) and fattening system
(pasture vs feedlot). During the 97 days period of dietary restriction target growth rates were 0.3 and 0.6 kg/d, for
moderate and mild groups, respectively. The dietary restriction period was followed by a subsequent fattening period
of 84 days. Methane emissions and DMD were measured at the end of fattening period in 36 and 80 steers, using SF6
and acid insoluble ash technique, respectively. During fattening, previous moderate restricted steers had higher LW
gain compared to mild steers (1.2 vs 1.0 kg/d; P<0.01). Feedlot steers had higher LW gain (1.3 vs 0.9 kg/d; P<0.01)
than pasture steers. Irrespective of previous dietary restriction treatment, methane emission and methane yield were
lower for feedlot steers (P<0.05; 230 vs 313 g CH4/d, and 22.2 vs 25.8 g CH4/kg DMI, respectively). No difference
in DMD was evident between previously restricted steers, whereas feedlot steers achieved higher DMD than pasture
steers (82.1 vs 69.2%; P<0.01). Moderate steers had lower methane intensity than mild steers (246 vs 321 g CH4/LW
gain; P<0.01). In conclusion, for both finishing systems, the lower methane intensity of steers initially subjected to a
moderate dietary restriction is due to their relatively higher performance during fattening, rather than lower methane
emissions or yield per se
Boiling vs. baking: Cooking-induced structural transformations drive differences in the in vitro starch digestion profiles that are consistent with the in vivo glycemic indexes of white and sweet potatoes
No full textPeer-ReviewedWhite and sweet potatoes can elicit different blood glucose responses depending on whether they are boiled or baked. This work investigated how microstructure and starch digestion in vitro relate to these differences. The main methods were INFOGEST’s semi-dynamic digestion protocol, Scanning Electron Microscopy and Confocal Laser Scanning Microscopy. The cooking method impacted microstructure, thereby significantly influencing starch digestion. Boiling and baking led to similar types of microstructural changes, including cell expansion and separation and disruption to cell walls, with the differences lying on the magnitude of such changes. Hydrolysis of white potato starch into oligosaccharides during oro-gastric digestion stabilized at around 75% when boiled compared to 50% when baked. In sweet potato, hydrolysis during this stage represented 30% and 40% of the total starch after boiling or baking, respectively. Overall, the effect can be summarized as boiled white potato > baked white potato > baked sweet potato > boiled sweet potato. Our results show how structural transformations that occur during cooking can drive differences in starch release and hydrolysis during in vitro digestions. This work therefore provides a structural and biochemical basis to better understand the impact of boiling and baking on the glycemic responses to these foods
Can dietary proteins selectively reduce either the visceral or subcutaneous adipose tissues?
Get PDFpeer-reviewedThere is a considerable appeal for interventions that can selectively reduce either the visceral or subcutaneous white adipose tissues in humans and other species because of their associated impact on outcomes related to metabolic health. Here, we reviewed the data related to the specificity of five interventions to affect the two depots in humans and rodents. The interventions relate to the use of dietary proteins, monounsaturated fatty acids, polyunsaturated fatty acids, calorie restriction, or bariatric surgery. The available data show that calorie restriction and bariatric surgery reduce both visceral and subcutaneous tissues, whereas there is no consistency in the effect of monounsaturated or polyunsaturated fatty acids. Dietary proteins, more specifically, whey proteins show efficacy to reduce one or both depots based on how the proteins interact with other macronutrients in the diet. We provide evidence that this specificity is related to changes in the composition and the functional potential of the gut microbiota and the resulting metabolites produced by these microorganisms. The effect of the sex of the host is also discussed. This knowledge may help to develop nutritional approaches to deplete either the visceral or subcutaneous adipose tissues and improve metabolic health in humans and other species
Plant species and soil depth differentially affect microbial diversity and function in grasslands
Get PDFpeer-reviewedSupplementary information (datafile) for Kerry B. Ryan, Alexandre De Menezes, John A. Finn (2023) Fiona P. Brennan, Datafile: Grassland species differentially affect microbial diversity and function with soil depthIntroduction
Grassland ecosystems are a major store of terrestrial carbon (C), yet little is known about their capacity to cycle and store C in deeper soil horizons. Further, it is unclear how plant community composition within agricultural grasslands mediates this capacity and influences microbial community composition. We investigated whether the aboveground community composition in intensively-managed agricultural grasslands influenced belowground microbial community composition, abundance, respiration and enzyme activities with depth.
Materials & methods
Soil was sampled in four soil layers: A (0-15 cm), B (15-30 cm), C (30-60 cm) and D (60-90cm) in monocultures of six grassland species, and a mixture of all six. Functional capacity was measured through enzymatic and substrate induced respiration assays, and microbial abundance and diversity were assessed via qPCR and sequencing (16S, ITS), respectively.
Results
Microbial abundance and C cycling enzyme activity decreased, and community composition changed, along the soil depth gradient, regardless of the plant community. Microbial abundance was not significantly influenced by plant community type across the entire soil depth profile. However, prokaryotic community composition was significantly influenced by plant community in the top 15 cm of soil, and fungal community composition was significantly influenced between 15-30 cm in depth. Plant community types mediated the rate at which C cycling enzyme activity decreased along the soil depth gradient, and selected C cycling enzymes were significantly more active at 15-60 cm depth when Cichorium intybus (a deep rooting species) was present.
Conclusion
This study provides an improved understanding of how agricultural grassland communities affect the soil microbiome with depth; this has potential implications for the management of these systems for enhanced soil health. Our work indicates the potential for multi-species mixtures with deep rooting species to be a practical strategy to increase C cycling capacity in deeper soil layers within grasslands, which may have implications for policy goals related to C storage
Utilising commercial farm grass growth data to evaluate long-term dry matter production of perennial ryegrass varieties
Get PDFLittle data are currently available on either the dry matter (DM) production of perennial ryegrass (PRG) swards as
they age beyond 5 yr (i.e. permanent pasture) or the performance of PRG varieties on commercial grassland farms.
Previous work has generally assumed a connection between DM production and ground score (GS) and this link
has been used as a proxy for variety persistence. The evolution of technology in the form of PastureBase Ireland
has led to agronomic data of individual paddocks being made available for analysis over multiple years which
has allowed the long-term assessment of varieties sown as monocultures on commercial farms. This technology
allowed for the inclusion of eight PRG varieties sown in 649 paddocks across 101 farms in Ireland in the current
analysis. The results show little association between GS and variety DM production as varieties age to 7 yr. Dry
matter production of 1- to 4-yr-old swards appeared to provide a strong indication of variety DM production in
years 5–7 post-sowing (r = 0.72, P < 0.05). The interaction of variety and sward age was not associated with DM
production. Generally, varieties which produced the most DM in younger swards also produced the most DM in
permanent pasture swards. Over longer-term periods these variety differences can manifest into large differences
in DM produced and consumed on farm. The current analysis suggests that the long-term production benefits of
utilising improved PRG varieties in pasture reseeding may be underestimated
Multi-breed, multi-tissue systems biology analysis of beef cattle divergent for feed efficiency
No full textProvision of feed in beef production systems is a major determinant of profitability. Thus, the identification of genes
implicated in regulating feed efficiency may allow for the selection and subsequent breeding of more feed efficient
cattle, with obvious benefits for sustainability. It is also crucial that gene markers identified as contributing to feed
efficiency are robust across various factors including breed type as well as environmental influence such as diet.
In this study, gene co-expression network analysis was undertaken on RNAseq data generated from Longissimus
dorsi and liver tissue samples collected from steers of two contrasting breed types (Charolais and Holstein-Friesian)
divergent, within breed, for residual feed intake (RFI), across contrasting dietary phases: ((1) high-concentrate; (2)
zero-grazed grass; (3) high-concentrate). Differentially expressed genes (DEG) based on the contrasts of breed, diet
and RFI phenotype were utilised as nodes of the gene co-expression networks. Significant network connections were
identified using an algorithm that exploits the dual concepts of partial correlation and information theory (PCIT).
PCIT network analysis resulted in the formation of three RFI specific clusters of co-expressed genes which were
separated by tissue type. Pathway analysis revealed enrichment (P<0.05) of biological processes related to fatty
acid biosynthesis in both liver and muscle clusters as well as immune-related pathways in a separate muscle specific
cluster. Genes contained within the immune-related cluster were also breed specific DEGs highlighting a potential
role for these genes as robust biomarkers for RFI across varying breed type. Acknowledgement: This research was
funded by the Irish Department of Agriculture, Food and the Marine (RSF13/S/519). Kate Keogh received funding
from the Research Leaders 2025 programme (co-funded by Teagasc and the European Union’s Horizon 2020, Marie
Skłodowska-Curie grant agreement number 754380)
Soil microbial community structures are shaped by agricultural systems revealing little temporal variation
No full textAim:
To determine if any differences in soil microbiome structures between both sharply contrasting,
slightly differing and quite similar agricultural systems persist through changing growth conditions.
Method:
Under field conditions, soil samples were taken from different agricultural systems; a sown
grassland to maize rotation (MC), an intensively managed permanent grassland (INT), as well as
extensively managed permanent grasslands with high (EXT_HP), low to sufficient (EXT_LP) and
deficient available P (EXT_DP), six times throughout the 2017 growing season. Soil DNA was
extracted, with the fungal internal transcribed spacer region (ITS2) and bacterial 16S rRNA gene
being PCR amplified and an amplicon-based Illumina Miseq sequence analysis conducted.
Results:
For both fungal and bacterial community structure, the influence of agricultural system (√CV =
0.256 and 0.145, respectively, both at least P < 0.01) was much greater than that of temporal
progression (√CV = 0.065 and 0.042, respectively, both P < 0.001). Importantly, nearly all
agricultural systems persistently harbored significantly distinct fungal community structures across
each of the six sampling events (all at least P < 0.05). There were not as many pairwise differences
in bacterial community structure between the agricultural systems, but some did persist (MC and
EXT_HP ~ EXT_DP, all P < 0.001).
Conclusions:
These results highlight the temporal stability of pairwise differences in soil microbiome structures
between established agricultural systems, even those with comparable management. This is a
highly relevant finding in informing the sampling strategy of studies in soil microbial ecology and for
designing efficient soil biodiversity monitoring systems
Microbiome predators in changing soils
Get PDFpeer-reviewedMicrobiome predators shape the soil microbiome and thereby soil functions. However, this knowledge has been obtained from small-scale observations in fundamental rather than applied settings and has focused on a few species under ambient conditions. Therefore, there are several unaddressed questions on soil microbiome predators: (1) What is the role of microbiome predators in soil functioning? (2) How does global change affect microbiome predators and their functions? (3) How can microbiome predators be applied in agriculture? We show that there is sufficient evidence for the vital role of microbiome predators in soils and stress that global changes impact their functions, something that urgently needs to be addressed to better understand soil functioning as a whole. We are convinced that there is a potential for the application of microbiome predators in agricultural settings, as they may help to sustainably increase plant growth. Therefore, we plea for more applied research on microbiome predators.TeagascArne Schwelm has received funding from the Research Leaders 2025 programme co-funded by Teagasc and the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie (grant agreement number 754380). Guixin Li acknowledges China Scholarship Council (CSC; grant no. 202006180073). Rutger A. Wilschut acknowledges funding from the Postdoc Talent Programme of the Wageningen Graduate Schools (WGS). Shunran Hu acknowledges financial support from CSC (No. 201913043) and Hainan University. Yuxin Wang acknowledges CSC (grant no. 202104910024)
Sustainable and healthy food consumption in Europe: an analysis of consumer purchase patterns, motivations and barriers towards foods from SFSCs
Get PDFpeer-reviewedThe aim of this paper is to better understand European consumers’ behaviour in relation to Short Food Supply Chains (SFSCs), so as to provide insights to support their development as part of a sustainable food system.. Specifically, it aims to analyse consumer purchase patterns, motivations and perceived barriers, and to identify patterns of behaviour amongst different consumer groups.
An online consumer survey was conducted in 12 European countries (n=2,419). Quantitative data analysis, including Principal Component Analysis (PCA) and cluster analysis, was undertaken using SPSS.
Four consumer clusters are named according to their behavioural stage in terms of SFSC engagement; Unaware Unengaged, Aware Unengaged, Motivationally Engaged, and Executively Engaged. Unaware Unengaged and Aware Unengaged are in the non-engagement phase of behaviour. Motivationally Engaged are motivationally activated to engage in the behaviour but fail to do so consistently. Executively Engaged is the fully engaged cluster, being motivated to act and purchasing local food on a frequent basis. The results show an interesting interplay between motivations and barriers, i.e. higher scores for motivations and lower scores for barriers do not necessarily translate into higher purchase frequency.
The research gleans insights into the contextual factors that may inhibit SFSC purchases in different consumer segments. It offers practical implications for policymakers and others seeking to develop SFSCs as part of a sustainable food system
Effect of breed and diet on the M. longissimus thoracis et lumborum transcriptome of steers divergent for residual feed intake
No full textImproving cattle feed efficiency through selection of residual feed intake (RFI) is a widely accepted approach to sustainable beef production. A greater understanding of the molecular control of RFI in various breeds offered contrasting diets is necessary for the accurate identification of feed efficient animals and will underpin accelerated genetic improvement of the trait. The aim of this study was to determine genes and biological processes contributing to RFI across varying breed type and dietary sources in skeletal muscle tissue. Residual feed intake was calculated in Charolais and Holstein–Friesian steers across multiple dietary phases (phase-1: high concentrate (growing-phase); phase-2: zero-grazed grass (growing-phase); phase-3: high concentrate (finishing-phase). Steers divergent for RFI within each breed and dietary phase were selected for muscle biopsy collection, and muscle samples subsequently subjected to RNAseq analysis. No gene was consistently differentially expressed across the breed and diet types examined. However, pathway analysis revealed commonality across breeds and diets for biological processes including fatty acid metabolism, immune function, energy production and muscle growth. Overall, the lack of commonality of individual genes towards variation in RFI both within the current study and compared to the published literature, suggests other genomic features warrant further evaluation in relation to RFI