Rajan Dhakal

Mr. Rajan Dhakal

University of Copenhagen, Copenhagen, Hovedstaden, Denmark
orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 May 2022 in Journal of Cleaner Production
Verified
Journal Article
Open access
DPDeepak Pandey
Deepak Pandey
HHHanne Helene Hansen
Hanne Helene Hansen
Rajan DhakalRajan Dhakal
Rajan Dhakal
Nabin AryalNabin Aryal
Nabin Aryal
SRSurya Prakash Rai
Surya Prakash Rai
PKPrabhat Khanal
Prabhat Khanal

10 May 2022 in Agriculture
Verified
Journal Article
Open access
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PKPrabhat Khanal
Prabhat Khanal
Rajan DhakalRajan Dhakal
Rajan Dhakal
TKTanka Khanal
Tanka Khanal
DPDeepak Pandey
Deepak Pandey
NDNaba Raj Devkota
Naba Raj Devkota
MNMette O. Nielsen
Mette O. Nielsen
In many developing countries, the livestock sector plays a vital role in the national economy, providing a source of food, income, and employment. With changes in demographical, socio-economic, and environmental status, the livestock sector in the developing world is facing challenges of low productivity and has become both a culprit and a victim of undesirable climate change impacts globally. In this paper, we will review the status of Nepalese livestock production systems and evaluate possible livestock species-specific strategies to promote a more productive and sustainable livestock sector in the future. In Nepal, the livestock sector is deemed essential to alleviate poverty and improve the nutritional status of the population, as in many other developing countries. However, there is a need for substantial improvements in livestock productivity, in particular improvement of feeding strategies to exploit the genetic potential of livestock. For ruminants, the important issue is to improve nutritional value and hence utilization of existing feedstuffs. Use of, e.g., urea, molasses, and enzymes to improve feed digestibility and implementation of technologies to effectively preserve biomass from forages that are only seasonally available are necessary strategic measures. Identification and use of novel anti-methanogenic feed ingredients will be crucial to develop a ruminant livestock sector that is not only productive, but also environmentally sustainable. For monogastric animals, the development and use of novel protein feed ingredients, such as insects raised on indigestible (for monogastrics) plant residues, should become part of future feeding strategies in support of a circular bioeconomy and improved productivity, not least in small scale poultry production. Future policies should also include a strong focus on capacity building and development of research infrastructure, and promotion of collaborative activities among research and industry sectors to establish a productive yet sustainable livestock sector in Nepal.

1 April 2023 in Fermentation
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Journal Article
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Rajan DhakalRajan Dhakal
Rajan Dhakal
GCGiuseppe Copani
Giuseppe Copani
BCBruno Ieda Cappellozza
Bruno Ieda Cappellozza
NMNina Milora
Nina Milora
HHHanne Helene Hansen
Hanne Helene Hansen
Direct-fed microbial products (DFM) are probiotics that can be used advantageously in ruminant production. The in vitro gas production technique (IVGPT) is a method to simulate rumen fermentation and can be used to measure degradation, gas production, and products of fermentation of such additives. However, inter-laboratory differences have been reported. Therefore, tests using the same material were used to validate laboratory reproducibility. The objective of this study was to assess the effect of adding two DFM formulations on fermentation kinetics, methane (CH4) production, and feed degradation in two different basal feeds while validating a newly established IVGPT laboratory. Six treatments, with three replicates each, were tested simultaneously at the established IVGPT lab at the University of Copenhagen, and the new IVGPT lab at Chr. Hansen Laboratories. Maize silage (MS) and grass silage (GS) were fermented with and without the following DFM: P1: Ligilactobacillus animalis and Propionibacterium freudenreichii (total 1.5 × 107 CFU/mL), P2: P1 with added Bacillus subtilis and B. licheniformis (total 5.9 × 107 CFU/mL). The DFM were anaerobically incubated in rumen fluid and buffer with freeze-dried silage samples for 48 h. Total gas production (TGP: mL at Standard Temperature and Pressure/gram of organic matter), pH, organic matter degradability (dOM), CH4concentration (MC) and yield (MY), and volatile fatty acid (VFA) production and profiles were measured after fermentation. No significant differences between the laboratories were detected for any response variables. The dOM of MS (78.3%) was significantly less than GS (81.4%), regardless of the DFM added (P1 and P2). There were no significant differences between the effects of the DFM within the feed type. MS produced significantly more gas than GS after 48 h, but GS with DFM produced significantly more gas at 3 and 9 h and a similar gas volume at 12 h. Both DFM increased TGP significantly in GS at 48 h. There was no difference in total VFA production. However, GS with and without probiotics produced significantly more propionic acid and less butyric acid than MS with and without probiotics. Adding P2 numerically reduced the total methane yield by 4–6% in both MS and GS. The fermentation duration of 48 h, used to determine maximum potential dOM, may give misleading results. This study showed that it is possible to standardize the methodology to achieve reproducibility of IVGPT results. Furthermore, the results suggest that the P2 DFM may have the potential to reduce CH4 production without affecting organic matter degradation.

9 July 2018 in Scientific Reports
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Journal Article
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AMAnupama Mukherjee
Anupama Mukherjee
Sabyasachi MukherjeeSabyasachi Mukherjee
Sabyasachi Mukherjee
Rajan DhakalRajan Dhakal
Rajan Dhakal
MMMoonmoon Mech
Moonmoon Mech
ILImsusosang Longkumer
Imsusosang Longkumer
GSGoutam Sahana
Goutam Sahana
The current study aimed at genomic characterization and improved understanding of genetic diversity of two Indian mithun populations (both farm, 48 animals and field, 24 animals) using genome wide genotype data generated with Illumina BovineHD BeadChip. Eight additional populations of taurine cattle (Holstein and NDama), indicine cattle (Gir) and other evolutionarily closely related species (Bali cattle, Yak, Bison, Gaur and wild buffalo) were also included in this analysis (N = 137) for comparative purposes. Our results show that the genetic background of mithun populations was uniform with few possible signs of indicine admixture. In general, observed and expected heterozygosities were quite similar in these two populations. We also observed increased frequencies of small-sized runs of homozygosity (ROH) in the farm population compared to field mithuns. On the other hand, longer ROH were more frequent in field mithuns, which suggests recent founder effects and subsequent genetic drift due to close breeding in farmer herds. This represents the first study providing genetic evidence about the population structure and genomic diversity of Indian mithun. The information generated will be utilized for devising suitable breeding and conservation programme for mithun, an endangered bovine species in India.

20 February 2024 in Frontiers in Microbiology
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Journal Article
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Rajan DhakalRajan Dhakal
Rajan Dhakal
ANAndré Luis Alves Neves
André Luis Alves Neves
RSRumakanta Sapkota
Rumakanta Sapkota
PKPrabhat Khanal
Prabhat Khanal
LELea Ellegaard-Jensen
Lea Ellegaard-Jensen
HHHanne Helene Hansen
Hanne Helene Hansen
Anaerobic in vitro fermentation is widely used to simulate rumen kinetics and study the microbiome and metabolite profiling in a controlled lab environment. However, a better understanding of the interplay between the temporal dynamics of fermentation kinetics, metabolic profiles, and microbial composition in in vitro rumen fermentation batch systems is required. To fill that knowledge gap, we conducted three in vitro rumen fermentations with maize silage as the substrate, monitoring total gas production (TGP), dry matter degradability (dDM), and methane (CH4) concentration at 6, 12, 24, 36, and 48 h in each fermentation. At each time point, we collected rumen fluid samples for microbiome analysis and volatile fatty acid (VFA) analysis. Amplicon sequencing of 16S rRNA genes (V4 region) was used to profile the prokaryotic community structure in the rumen during the fermentation process. As the fermentation time increased, dDM, TGP, VFA concentrations, CH4 concentration, and yield (mL CH4 per g DM at standard temperature and pressure (STP)) significantly increased. For the dependent variables, CH4 concentration and yield, as well as the independent variables TGP and dDM, polynomial equations were fitted. These equations explained over 85% of the data variability (R2 > 0.85) and suggest that TGP and dDM can be used as predictors to estimate CH4 production in rumen fermentation systems. Microbiome analysis revealed a dominance of Bacteroidota, Cyanobacteria, Desulfobacterota, Euryarchaeota, Fibrobacterota, Firmicutes, Patescibacteria, Proteobacteria, Spirochaetota, and Verrucomicrobiota. Significant temporal variations in Bacteroidota, Campylobacterota, Firmicutes, Proteobacteria, and Spirochaetota were detected. Estimates of alpha diversity based on species richness and the Shannon index showed no variation between fermentation time points. This study demonstrated that the in vitro fermentation characteristics of a given feed type (e.g., maize silage) can be predicted from a few parameters (CH4 concentration and yield, tVFA, acetic acid, and propionic acid) without running the actual in vitro trial if the rumen fluid is collected from similar donor cows. Although the dynamics of the rumen prokaryotes changed remarkably over time and in accordance with the fermentation kinetics, more time points between 0 and 24 h are required to provide more details about the microbial temporal dynamics at the onset of the fermentation.

1 January 2021 in Food Science of Animal Resources
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Journal Article
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VRVahid Ranaei
Vahid Ranaei
ZPZahra Pilevar
Zahra Pilevar
CEChangiz Esfandiari
Changiz Esfandiari
AKAmin Mousavi Khaneghah
Amin Mousavi Khaneghah
Rajan DhakalRajan Dhakal
Rajan Dhakal
HHHedayat Hosseini
Hedayat Hosseini
Food Science of Animal Resources (Food Sci. Anim. Resour.) is an international, peer-reviewed bimonthly journal publishing original research and reviews on basic and applied aspects of the use of animal resources including the meat, egg, dairy, and edible insect/worm products. Food Sci. Anim. Resour. is published and distributed by the Korean Society for Food Science of Animal Resources.