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Microalgae production cost in aquaculture hatcheries
No full textMicroalgae are a crucial part in many aquaculture feed applications processes, mainly in hatcheries. Many aquaculture hatcheries maintain a small scale microalgae production facility in-house for the production of live feed. Microalgae are usually grown in non-automated bubble-column systems at unknown production costs. Other reactor systems or scenarios utilizing artificial light or sunlight and at different scales could result in a more cost efficient production processes. To determine the cost-price and cost-distribution of microalgae production facilities in Dutch aquaculture industry and identify the most efficient cost reducing strategies a techno-economic analysis for small scale microalgae production facilities (25-1500 m2) was developed. Commercially available reactors commonly used in aquaculture were compared; tubular photobioreactors (TPBR) and bubble-columns (BC) in two placement possibilities; using artificial light in an indoor facility (AL) and utilizing sunlight in a greenhouse (GH) under Dutch climate conditions. Data from commercial microalgae facilities in the Netherlands are used to model reference scenarios describing the cost price of microalgae production with state of the art technology in aquaculture for a biomass production capacity of 125 kg year−1. The reference cost price for algae biomass (on the basis of dry matter) is calculated at €290,- kg−1 and € 329 kg−1 for tubular reactors under artificial light and a greenhouse, respectively and €587,- kg−1 and €573 kg−1 for bubble-columns under artificial light and a greenhouse, respectively. The addition of more artificial light will significantly reduce production costs (by 33%) in all small-scale systems modelled. Biomass yield on light (Yx,ph) showed the largest effect on cost price when not considering a different scale of the production process. Process parameters like temperature control should be aimed at optimizing Yx,ph rather than other forms of cost reduction. The scale of a microalgae production facility has a very large impact on the cost price. With state of the art technologies a cost price reduction of 92% could be achieved by changing the scale from 25m2 to 1500m2, resulting in a cost price of €43,- kg−1, producing 3992 kg year−1 for tubular reactors in a greenhouse. The presented techno-economic model gives valuable insights in the cost price distribution of microalgae production in aquaculture. This allows to focus research efforts towards the most promising cost reduction methods and to optimize existing production facilities in aquaculture companies to achieve economically sustainable microalgae production for live feed in hatcheries.</p
Small angle neutron scattering quantifies the hierarchical structure in fibrous calcium caseinate
No full textPronounced fibres are formed through simple shearing of a dense calcium caseinate dispersion. Both mechanical tests and scanning electron microscopy images demonstrate that the material is anisotropic. It is hypothesised that calcium caseinate aggregates, under shear, align into micro-fibres and bundle further into a hierarchical structure. Yet no direct evidence at the sub-micron length scale can support the assumption. Small angle neutron scattering (SANS) experiments were conducted on calcium caseinate samples prepared at different conditions. Analysis of the SANS data revealed that the micro-fibres have a diameter of ∼100nm and a length of ∼300nm. The addition of enzyme and air contributed to longer and thinner micro-fibres. Furthermore, the extent of fibre alignment at the micro-scale and the macroscopic anisotropy index followed the same trends with varying processing conditions. It is concluded that the material does indeed possess a hierarchical structure and the micro-fibres are responsible for the anisotropy on the macro-scale.</p
Phenotyping with fast fluorescence sensors approximates yield component measurements in pepper (Capsicum annuum L.)
No full textMolecular breeding, a powerful technique to increase crop yield, tries to predict yield by crop growth models with genotype specific, environment-independent yield components and environmental indices as inputs. A fluorescence-trait-based approach is presented to approximate some costly and time-consuming measurements of yield components. Temporal monitoring of chlorophyll a fluorescence resulted in fluorescence traits with high heritability (0.60–0.82) that could act as proxies for model inputs. Medium-sized Pearson's correlations were calculated between fluorescence traits, light-use efficiency (LUE), and fruit related parameters up to 0.53. Multi-trait quantitative trait locus (QTL) analyses identified genomic regions of pepper (Capsicum annuum L.) involved in the phenotypic variation of the fluorescence traits. Fluorescence QTLs found on linkage groups P6, P7, and P11 corresponded to QTLs for number of fruits, partitioning into fruits, and LUE. Fluorescence parameters within 1 min of the fluorescence response curve can thus be useful to approximate yield component traits
Opportunities for improving the dairy sector in Romania
No full textRomania is a milk importing country. Dairy farming in the country is small-scale but offers good prospects. The level of agricultural knowledge among farmers is still low due to insufficient agricultural education. Dutch businesses are active in Romania to develop dairy farming but are running up against this low level of knowledge. This report describes the experiences of transferring knowledge to farmers and advisors in central Transylvania
Gene banking and transplantation of (mammalian) ovarian tissue
No full textThe use of cryopreserved gonadal tissue to reconstitute breeds or breeding lines has been demonstrated in birds (Silversides et al., 2013; Liptoi et al., 2013) and mammals (e.g. Huang et al., 2010) as a highly effective, efficient method. For large domestic mammals, such as the pig, proof of principle needs to be demonstrated. We (Egerszegi et al., unpublished) have undertaken a small pilot experiment in which orthotopic homografting of fragments of juvenile pig ovaries into neonate ovariectomized recipient piglets was attempted. This attempt was not successful. The results of the study are briefly presented in this report. This report further presents a literature review to describe current possibilities in various mammalian species and to provide suggestions for potential future improvements of methods in pigs or other mammalian farm animal species
Warts wars : The resistant potatoes strike back
No full textPotato wart disease, caused by the obligate biotrophic Chytrid fungus Synchytrium endobioticum, is one of the most important quarantine diseases of potato. This disease was named after the symptoms caused by the pathogen, which are the proliferation of meristematic tissues leading to the formation of warts, mainly on the below-ground sprouts of potato plants. The quarantine status of S. endobioticum is due to the production of spores that can remain viable in the soil for more than 40 years, the lack of chemical control and the severe yield losses. In Europe, more than 40 different pathotypes of S. endobioticum have been recorded and only resistance to pathotype 1 is commonly deployed in the breeding germplasm. The breeding and cultivation of potato varieties resistant to a wider spectrum of pathotypes is crucial for quarantine practice to reduce the propagation of the pathogen. Therefore, the identification of genes bringing resistance to the most frequent pathotypes of the pathogen and the development of diagnostic markers for marker assisted selection (MAS) is urgently needed. In this thesis, genes involved in resistance to pathotypes 1, 2, 6 and 18 of S. endobioticum were identified to make an inventory of the different resistance sources at hand for potato breeders. In Chapter 2, we investigated the distribution of the pathotype 1 resistance in a variety panel representative of the potato breeding material. Breeding programs of the 20th century were very successful in producing varieties resistant to pathotype 1 as 77% of the panel varieties were found to be resistant. To identify markers linked with pathotype 1 resistance, we used previously produced genotypic and phenotypic data to perform a Genome-Wide Association Study (GWAS). The GWAS resulted in the identification of markers associated with pathotype 1 resistance on the north arm of chromosome 11. In this region, the major effect gene Sen1 was previously identified. Sen1 is the main source of pathotype 1 resistance in the variety panel and no common ancestral donor could be identified due to the inability to define identity-by-descent (IBD). As we faced limitations to design markers fully diagnostic for pathotype 1 resistance using the GWAS approach, we aimed to develop new tools to identify haplotype specific SNPs. In Chapter 3, we developed a new set of workflows, called Comparative Subsequence Sets Analysis (CoSSA), for the genetic analysis of traits of interest and the identification of haplotype specific SNPs. CoSSA can be used for any crop as it is suitable for polyploids and can be used with or without a reference genome. We applied CoSSA to identify Sen3, a dominant gene conferring resistance to all tested pathotypes. Sen3 was fine-mapped to the resistance gene cluster C76 on the north arm of chromosome 11. Furthermore, we used CoSSA for the fine-mapping of Sen1 in Chapter 4. Sen1 was mapped to the same R gene cluster as Sen3. We performed a candidate gene analysis and showed that Sen1 encodes a nucleotide-binding domain, leucine rich containing (NLR) protein from the TNL group. The two identified candidate genes were cloned and tested in complementation assays with AvrSen1, the S. endobioticum effector protein which triggers Hypersensitive Responses (HR) in Sen1 plants. These findings will serve as novel tools to study the interactions between potato and S. endobioticum. In Chapter 5, we made an, as complete as possible at this moment, inventory of the dominant potato wart disease resistance (Sen) genes and QTLs present in the potato breeding germplasm. We combined the GWAS and CoSSA strategies to identify two new major genes, Sen4 and Sen5, which are involved in resistance to pathotypes 2, 6 and 18. We also identified several wart disease resistance QTLs which, in combination with the dominant genes, can contribute to improve resistance to the higher pathotypes. To avoid any confusion between the previously and newly identified QTLs, we introduced a new naming system which allows to differentiate each resistant haplotype identified. Finally, we screened a broad panel of potato varieties and wild Solanum species for the genes Sen1, Sen2, Sen3, Sen4 and Sen5. To put it in a nutshell, a complete picture of the major potato wart disease resistance sources present in the breeding germplasm is given in this thesis. Haplotype specific markers have been designed for all the major genes and QTLs mapped, which will facilitate the breeding of resistant varieties. Finally, the development of CoSSA will facilitate the mapping of traits of interest and the design of haplotype specific markers for any crop
