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Teagasc Research News – Spring 2009

26 February 2009 Teagasc

Bioencapsulation – creating a safe haven for sensitive ingredients
Consumers are becoming more health conscious and food manufacturers are pursuing innovative ways to produce food that can deliver specific health benefits without compromising the taste or quality of their products. Incorporation of bioactive compounds, or ‘nutraceuticals’, into food systems can provide a simple way to develop novel ‘functional foods’ with health-promoting and/or disease-preventing properties. Examples of functional foods are probiotic (live bacteria) drinks or cholesterol-lowering spreads.

Bioencapsulation, or entrapment, is the process by which the active ingredient is densely packed into minute particles of liquid or solid material (encapsulant) or coated by a shielding material.

“Bioencapsulation is going to play an important role in the development of food that contains added health-promoting ingredients,” explains Dr André Brodkorb in the latest issue of TResearch, Teagasc’s research and innovation magazine.

Brodkorb and his colleagues in Moorepark Food Research Centre are working on the bioencapsulation of probiotics.

“Many bioactive ingredients are reactive and can interact with other food ingredients. The results are often undesired secondary products, or even degradation of the bioactive material and, ultimately, a loss in the commercial value of the food product. Encapsulation can prevent this by shielding the bioactives from detrimental environmental conditions met during processing, shelf-life and gastro-intestinal digestion, such as heat, low pH, oxygen, digestive enzymes and bile salts,” Brodkorb explains.

“In Teagasc, we are interested in developing novel technologies to ensure high probiotic survival during processing, storage and gastric transit. Probiotics entrapped in gel particles made from dairy protein/polysaccharide formulations showed good viability in various liquid and gel food products,” says Brodkorb.

Economic analysis of the returns from biomass crops
The payback period from investing in willow as an energy crop is 16 years and for miscanthus is nine years, according to an article by Daragh Clancy and colleagues in the  Teagasc Rural Economy Research Centre and UCD, who have been analysing the returns from willow and miscanthus production in Ireland. Farmers who diversify into biomass crops can receive establishment grants to offset part of the initial set-up costs.

The research addresses some of the information deficit about the economics of biomass crops in Ireland. They found that, given realistic assumptions and costings, both willow (1.62%) and miscanthus (10.15%) generate positive internal rates of return and can, therefore, be considered financially viable. However, at least in the case of willow, the additional return is probably too low for most farmers to invest in this enterprise, while foregoing average returns from a conventional enterprise. Miscanthus consistently outperformed willow in terms of investment performance. Consequently, based on these results, miscanthus is most likely to be the biomass crop of choice.

The price level is also highly uncertain as the market for energy crops in Ireland is still in its infancy. Moreover, the lengthy production lifespan of energy crops serves to heighten the level of risk associated with key parameters. Uncertainty about critical variables such as the annual yield level and the energy price make it difficult to accurately calculate the returns of such investments. However, ongoing research projects in Teagasc Oak Park Crops Research Centre are addressing these knowledge deficits.

“Accordingly, it can be expected that the risk-averse nature of many farmers is likely to hinder widespread adoption during the pioneer stage of the bioenergy market in Ireland. More widespread adoption is only likely when the economic merits of these crops have been proven over an extended period,” concluded Clancy.

Banking on DNA
A new DNA bank offers huge opportunities for improvement of cattle breeding. Researchers from the Animal Bioscience Centre (Grange and Athenry) and Moorepark Research Centre have been collaborating on its establishment. The sequencing of the bovine genome has been completed and presents new opportunities to discover the influence of genes on a range of performance traits in cattle.

The sites along the DNA sequence that show variation among animals are called polymorphisms. This term is becoming widely used as genomic technologies begin to play an increasingly important role in animal breeding. Differences in even one nucleotide, or single nucleotide polymorphism (SNP – pronounced ‘snip’), can result in a change in expression level of the gene or a change in function of the gene product. Such changes can affect the performance of the animal. The challenge and opportunity, is to identify the genetic basis or SNPs controlling economically important traits such as growth rate, feed efficiency, animal health, fertility and milk production, and to integrate the favourable allele into the commercial cattle population.

A DNA bank resource for Irish dairy and beef cattle is currently being established at Teagasc. To date, protocols for the extraction and storage of DNA from blood, semen and other tissues have been evaluated, optimised and standardised. DNA from more than 6,500 cattle has been extracted, including dairy and beef AI sires as well as the Teagasc dairy research herds. Currently, 4,500 dairy cows from several different breeds are represented in this DNA bank. Research will generally involve three steps: 1) identification of genetic differences among animals at the DNA level; 2) quantification of the association between the identified genetic variants and traits of importance in cattle, and validation of these results in independent populations; and, 3) exploitation of the results in a breeding programme.

For example, if a ‘beneficial’ genetic variant is identified, then animals possessing this variant can be included by breed organisations or breeders in subsequent breeding programmes. Appreciation of this fact has led to the development of the concept of ‘genomic selection’. Genomic selection involves simultaneous estimation of the associations between thousands of SNPs and economically important traits, and the selection of animals that have the best ‘DNA signature’ across the thousands of SNPs. The research underpinning genomic selection for Irish dairy cattle is currently underway at Teagasc, Moorepark, in conjunction with the national dairy cattle breeding programme, and is being implemented this Spring. The Teagasc DNA bank is fundamental to the development of the genomic selection breeding programme for Ireland. To date, over 1,000 Holstein-Friesian dairy sires, whose DNA was extracted from semen, have been genotyped. This population will act as the foundation population for estimating the SNP associations. Genomic selection is particularly useful for young animals and for traits that are associated with gender (e.g., milk yield can only be measured in females), traits that take a long time to measure (e.g., measures of daughter survival to fourth lactation are only available when a bull is at least seven years of age), traits where there are considerable management effects or errors in recording (e.g., fertility), and traits that are difficult to measure (e.g., feed efficiency).

Research from Ireland suggests that genomic selection will increase genetic gain by 50%, or in other words, an increase in annual rate of genetic gain in Economic Breeding Index (EBI) in dairy cows from €23/year to €35/year, which is worth €2.5m annually to the dairy industry and is cumulative and permanent.

Attached files

  • Confocal microscopy images of probiotic bacteria entrapped in a gel particle. Live bacteria appear green.

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