CABI Blogs: hand picked... and carefully sorted

Glycerol, a Byproduct of the Biodiesel Industry, in Livestock Feeds

The rapid growth of ethanol and biodiesel production in the United States and elsewhere has raised questions about possible uses for the byproducts of this industry. To date the use of ethanol byproducts, in particular distillers' dried grains with solubles, in animal feed has received much attention. The burgeoning biodiesel industry on the other hand, has resulted in glycerine, the principal byproduct, flooding the market. While glycerine is widely used in the soap, cosmetic and food industries, the biodiesel industry is producing more than the market can cope with. This has led to renewed efforts to find new uses for glycerine, e.g. as a boiler fuel source, as animal feed, for the production of propylene and ethylene glycol, and the possibility of glycerine replacing petrochemicals.

Although several studies have evaluated the use of glycerine in diets for poultry, pigs and ruminants [1-8], its high cost then meant it was not cost-effective to use as an animal feed. However, the current low cost of glycerine and its value as an energy source has prompted several research groups to evaluate the nutritive value of glycerine and its use in livestock diets.

Researchers at the University of Arkansas' Center of Excellence for Poultry Science examined the possibility of using glycerine as a dietary supplement in growing broiler chickens. In a short-term preliminary trial, Park Waldroup and his research team found that as much as 10% glycerine could be fed to to chickens up to 16 days of age without any detrimental effects on growth performance or meat quality. While 5% glycerine had no effect on body weight, feed intake, feed conversion or mortality, 10% glycerine affected feed flow rate (in the feeders used), reducing feed intake and consequently reduced body weight. Although the results suggest that glycerine can be used as an energy source in broiler diets, Waldroup cautioned that additional research was needed to evaluate the quality of the glycerine used and its effect on feed texture and pellet quality.

Researchers from Iowa State University and the US Department of Agriculture have been conducting studies on the feasibility of using glycerine in pig and poultry diets. In a metabolism study in which nursery and finishing pigs were fed 5, 10 and 20% glycerine, glycerine was readily used by pigs and found to have an energy value similar to corn. In a growth study, pigs fed on 5 and 10% glycerine from weaning to market weight showed the same growth performance as those fed on a conventional corn-soyameal diet. When 20% glycerine was used, flow rate problems were encountered leading the researchers to conclude that 10% inclusion was perhaps the upper limit. A metabolism trial conducted with hens fed on 0, 5, 10 or 15% glycerine showed no adverse effects on egg production, egg weight, or feed intake; the energy in the glycerine was also efficiently utilised. Although data from these trials on the effect of glycerine on meat quality have yet to be analysed, other studies suggest that the inclusion of glycerol can improve pig meat quality by reducing drip loss [5] and increase breast yield in broilers by improving protein deposition [9].

In a 6-month study that began this month at the University of Missouri-Columbia, Monty Kerley, professor of ruminant nutrition, is examining the effectiveness of glycerin (0, 5, 10 or 20%) as cattle feed using 60 calves from various breeds. In addition to monitoring feeding limits and growth patterns, glycerine metabolism in cattle will also be studied. Kerley sees the use of glycerine as cattle feed as a short-term option as he believes in time newer industrial applications for glycerine could price it out of the animal feed industry.

Thus glycerol appears to have promise as an energy source in animal diets. However, more studies are needed about the quality of glycerol from biodiesel production before its use can be recommended in animal feeds.

The CAB Abstracts database contains the abstracts of several papers on the use of glycerine in livestock diets.

References
[1] Kijora C, 1996. Utilization of glycerol as a byproduct of "Biodiesel" production in animal nutrition. Landbauforshung Volkenrode 169:151-157.
[2] Kijora C, Bergner H, Kupsch RD, Hagemann L, 1995. Glycerol as a feed component in fattening pigs. Archiv fur Tierernahrung 47:345-360.
[3] Kijora C, Kupscy RD, Bergner H, Wenk C, Prabucki AL, 1997. Comparative investigation on the utilization of glycerol, free fatty acids, free fatty acids in combination with glycerol and vegetable oil in fattening of pigs. Journal of Animal Physiology and Animal Nutrition 77:127-138.
[4] Kuhn M, 1996. Use of technical rapeseed-glycerol from Biodiesel production in the fattening of pigs. Landbauforshung Volkenrode 169:163-167.
[5] Mourot J, Aumaitre A, Mounier A, Peiniau P, Francois AC, 1994. Nutritional and physiological effects of dietary glycerol in the growing pig. Consequences on fatty tissues and post mortem muscular parameters. Livestock Production Science 38:237-244.
[6] Schröder A, Südekum K-H, 1999. Glycerol as a by-product of biodiesel production in diets for ruminants. 10th International Rapeseed Congress, Canberra, Australia. 6 pp. http://www.regional.org.au/au/gcirc/1/241.htm Accessed 31 May 2007.
[7] Simon A, Bergner H, Schwabe M, 1996. Glycerol as a feed component for broiler chickens. Archiv fur Tierernahrung 49:103-112.
[8] Simon A, Schwabe M, Bergner H, 1997. Glycerol supplementation to broiler rations with low crude protein content. Archives in Animal Nutrition 50:271-282.
[9] Cerrate S, Yan F, Wang Z, Coto C, Sacakli P, Waldroup PW, 2006. Evaluation of glycerine from biodiesel production as a feed ingredient for broilers. International Journal of Poultry Science 5:1001-1007.

Suggested further reading
Niles D, 2006. Combating the glycerine glut. Biodiesel 3:38-44. http://www.biodieselmagazine.com/article.jsp?article_id=1123 Accessed 31 May 2007.
Van Heugten E, 2007. Byproducts from energy production for swine. Swine News May 2007. North Carolina State Swine Extension, p. 2-4. http://mark.asci.ncsu.edu/Swine_News/2007/sn_v3004%20(May).htm Accessed 31 May 2007.
Waldroup PW, 2007. Biofuels and broilers - competitors or cooperators? Proceedings of the 5th Mid-Atlantic Nutrition Conference 2007, Zimmermann NG, ed, University of Maryland, Maryland, USA. http://www.ddgs.umn.edu/articles-poultry/2007-Waldroup-%20Biofuels%20and%20broilers%20(MANC).pdf  Accessed 31 May 2007.

Not all doom and gloom (but not far off)...

A news item from Botanic Gardens Conservation International (BCGI)  has reported on the Plant a Billion Trees campaign started in January.  The aim was to have 1 billion trees planted by the end of this year.  This target has not only already been met but more that 13 million trees over the 1 billion have been pledged, with the figure rising all the time. 

Rice fields on former mangrove forest, Sulawesi.  Mongabay.com

The idea came out of the UN Climate Change Conference in Nairobi, and is a worldwide tree planting campaign, but the Plant for the Planet: Billion Tree Campaign encourages the planting of trees in four key areas, namely:
(i) degraded natural forests and wilderness areas;
(ii) farms and rural landscapes;
(iii) sustainably managed plantations; and
(iv) urban environments.                     
United Nations Environment Programme (UNEP)

It is argued that planting trees in cooler climates may not help to combat global warming but the UNEP states that “the loss of natural forests around the world contributes more to global emissions each year than the transport sector.  Curbing deforestation is a highly cost-effective way to reduce emissions.”

I thought I would highlight this bit of cheer because in just the last few days plenty of bad news has been reported e.g., digging up the Malaysian forest to bury dead people; and the shrinking of New Zealand’s forests for the second year in a row, where “a third of forests being clear-felled - about 12,900ha - are not being replanted”.  This month it was also confirmed by researchers publishing in Science that “tropical deforestation produces 20 per cent of all carbon emissions caused by humans and destroys long-term carbon sinks”.  However we are doing our bit in the UK, threatening the stability of an ancient forest, and many of the species that live within it, by expanding an airport to enable 10 million more people a year to fly to wherever they need to go.

The volume of depressing news may be as much an indication of the way the global media reports what’s going on in the world, but a search in CAB Abstracts for deforestation, restricted to the last 6 months, gives 221 results – telling, whichever way you look at it.

Melamine contamination is spreading to meat and fish supplies

Melamine contamination of pet food in North America is more than two months old story now, but the end of crisis is still nowhere in sight. Thousands of dogs and cats that have eaten contaminated foods have suffered kidney problems or died, although there are somewhat conflicting reports as to the actual numbers of pets that were affected (see my previous blog). The US Food and Drug Administration (FDA) has identified melamine and melamine-related compounds in a consignment of wheat gluten and rice protein concentrate imported from China and used to make many brands of pet food as the main culprit.  Chinese suppliers are suspected of intentionally adding melamine to make it appear that their products were higher in protein content, which translates to a higher price. Melamine has no nutritional value but is about two-thirds nitrogen by weight, and nitrogen levels are often used as crude indicators of protein content in food commodities. It has been know for a long time that feed manufacturers may intentionally add melamine to animal feeds as a paper by Cattaneo & Ceriani (1988) demonstrated. The abstract of this paper can be seen in Animal Science database.

The FDA's findings triggered one of the largest pet food recalls in U.S. history. Since 16 March, 18 companies have recalled more than 5,600 pet food products. The recalls, however, do not seem to have come to an end. The latest addition to the recall list includes the dry dog food Nutra Nuggets, manufactured by Diamond Pet Foods of Meta, Missouri, which have tested positive for melamine and caused kidney problems in at least four dogs in California.

Climate change clock ticking for wild relatives

International Biodiversity Day is here, and CGIAR brings us news that climate change threatens the wild relatives of cultivated potatoes and peanuts. The CGIAR study warns that 61% of wild peanut and 12% of wild potato species could be made extinct over the next half century. This poses a problem for plant breeders and GM crop producers alike. Wild relatives are a vital source of genetic diversity for crop improvement and if that pool of resources is diminished, genes which confer resistance to pathogens for example, are lost.

Andy Jarvis of CGIAR explains "The vulnerability of a wild plant to climate change can depend on its ability to adapt by, for example, extending its range as warming in its native regions becomes too hot to handle. One reason wild peanut plants appear to be so vulnerable to climate change is they are largely found in flat lands and would have to migrate a long way to reach cooler climates, a predicament exacerbated by the fact that peanuts bury their seeds underground, a meter or less from the parent plant. That limits the speed at which seeds can move into more favorable climates. By contrast, plants in mountainous locations could theoretically survive by extending their range slightly up a slope, even by only a few meters, to find cooler weather."

International Day for Biological Diversity

Today, May 22nd 2007, is “International Day for Biological Diversity”.

As designated by the Secretariat of the Convention on Biological Diversity, the theme of the day, this year, is to raise awareness of the link between Biodiversity and Climate Change. If you visit here, the Secretariat has provided resources (posters and videos) in six different languages, covering most of the global population, to help draw attention to this year’s theme.

According to a statement on the Secretariat website “climate change is already forcing biodiversity to adapt either through shifting habitat, changing life cycles, or the development of new physical traits. The recently extinct Golden Toad (Bufo periglenes) and Gastric Brooding Frog (Rheobatrachus silus) have already been labelled as the first victims of climate change.”

Given the importance of the climate change biodiversity link, the Secretariat concludes with four key aims that we should undertake on a global scale:

1. Conserve biodiversity that is especially sensitive to climate change.

2. Preserve habitats so as to facilitate the long-term adaptation of biodiversity.

3. Improve our understanding of climate change biodiversity linkages.

4. Fully integrate biodiversity considerations into mitigation and adaptation plans.   

Hunting both animals and plants

Many people are aware of the negative effects of hunting on the species that are being hunted, especially on large-bodied, slow-reproducing forest vertebrates, but have you ever considered the knock-on effects on the plant community in those same ecosystems? The latest issue of Biotropica (vol. 39, no. 3) features a special section on the ‘Pervasive consequences of hunting for tropical forests’, which looks at the consequences of hunting on seed dispersal and plant species composition.

Hunting levels have been increasing, especially over the last 50 years when the importance of hunting for subsistence has been increasingly outweighed by hunting for the market. Drs Carlos Peres and Erwin Palacios report that "The total extent of partially defaunated, but otherwise "pristine" tropical forests, is often severely underestimated. For example, subsistence hunters have access to most areas of lowland Amazonia, affecting even the core of many relatively remote nature and indigenous reserves". Several factors are contributing to the overexploitation of forest game. Dr Joseph Wright and his colleagues write "The weak economies of many tropical countries fail to provide sufficient jobs for their growing populations, while land-use change, improved infrastructure, and new technology facilitate commercial hunting." Land-use change, often resulting in fragmentation, brings hunters and their markets closer to previously remote forests, while improved infrastructure, for example building of roads for timber and mineral extraction, provides access to forest interiors and to distant urban markets. All of this leads to an increase in the return for time spent hunting.

Virus Threatens Scotland's Red Squirrels

The first case of a red squirrel in Scotland dying as a result of the squirrelpox virus has sadly been reported by Scottish Natural Heritage. The red squirrel (Sciurus vulgaris) is one of the most threatened species of mammal in the UK, and Scotland supports 75% of the UK's remaining red squirrel population.

Squirrelpox virus was first detected in Scotland in invasive populations of non-native grey squirrel (Sciurus carolinensis) in May 2005. The competing grey squirrels carry the virus, showing no signs of disease, but when transmitted to the native red squirrel the virus is invariably fatal. Targeted grey squirrel control has helped prevent the progression of the disease to Scottish red squirrels until now.

Squirrelpox virus is known to be one of the significant factors in the catastrophic decline of red squirrels in the UK. The virus has caused the deaths of hundreds of red squirrels in England and, in February, a red squirrel died for the first time in Wales from the virus. Whilst searching CAB Abstracts for information, it was worrying to read that the rate of red squirrel replacement by grey squirrels is some twenty times faster in those areas where grey squirrels carry the virus^1,2.

In February 2006, a conference on Red squirrel conservation in Scotland resulted in the preparation of The Scottish Red Squirrel Action Plan 2006-2011 which makes a number of recommendations for the long-term conservation of the species, including development of a vaccine against squirrelpox virus. Let's hope the plan works.

To search CAB Abstracts comprehensively for squirrelpox virus, note the following variations of the virus name: squirrel parapoxvirus, squirrel poxvirus
(The virus was originally classified as a parapoxvirus but recent phylogenetic analyses suggests that this is incorrect^3,4).

1. Squirrel poxvirus: landscape scale strategies for managing disease. Gurnell, J., Rushton, S. P., Lurz, P.W.W., Sainsbury, A.W., Nettleton, P., Shirley, M.D.F., Bruemmer, C., Geddes, N. Biological Conservation, 2006, Vol. 131, No. 2, pp. 287-295.2.
2. Disease threats posed by alien species; the role of a poxvirus in the decline of the native red squirrel in Britain. Rushton, S.P., Lurz, P.W., Gurnell, J., Nettleton, P., Bruemmer, C., Shirley, M. D., Sainsbury, A. W. Epidemiology and Infection, 2006, Vol. 134, No.3, pp. 521-533.
3. A novel poxvirus lethal to red squirrels (Sciurus vulgaris). Thomas, K., Tompkins, D.M., Sainsbury, A.W., Wood, A.R., Dalziel, R., Nettleton, P.F., McInnes, C.J. Journal of General Virology, 2003, Vol. 84, No. 12, pp. 3337-3341.
4. Genomic characterization of a novel poxvirus contributing to the decline of the red squirrel (Sciurus vulgaris) in the UK. McInnes, C. J. , Wood, A. R. , Thomas, K. , Sainsbury, A. W. , Gurnell, J. , Dein, F. J. , Nettleton, P. F. Journal of General Virology, 2006, Vol. 87, No. 8, pp. 2115-2125.

The art of...boiling broccoli

Anyone out there still boiling your broccoli - stop now! Research from the University of Warwick says that this treatment seriously reduces the cancer fighting glucosinolate content- up to 77% if you do it for half an hour. They also suggest that freezing is not the best way to store these vegetables as it also reduces glucosinolate levels.

My reaction to this bit of news was - yes interesting about glucosinolate content after cooking and also interesting that storage in the freezer appears not to be good for glucosinolate content either especially as some vitamins are preserved by freezing, but - half an hour? Who does that these days? The broccoli would be falling apart! A straw poll round the office shows 10 minutes would be more usual. According to the research however, this still inflicts substantial losses of glucosinolates- up to 50%.

What cooking method is best to maximise one’s glucosinolate intake then? Well the researchers say steaming and frying for a few minutes are OK and this in agreement with some previous research (see search below). However a paper by Conway et al.¹ suggests brassicas like broccoli and cabbage are actually better eaten raw because myrosinase, the enzyme needed to convert the glucosinolates into cancer fighting isothiocyanates is then more active - heating inactivates it.

Why did people get into the habit of boiling their green vegetables for so long anyway? Apart from perhaps being uninterested in their food or too busy, that is. This paper by Niti Sharma et al.² is giving the clue - bitter taste. Glucosinolates taste bitter and boiling reduces the bitterness. You can’t win. Plant breeders and food scientists are getting headaches over the problem of reducing bitter taste but keeping the phytochemicals. For a review on consumers and the bitter taste in vegetables see Drewnowski et al.³

If you do still want to boil your greens to death, perhaps you should drink the cooking water too or use it to make something else, then you’ll get the leached glucosinolates back. My grandmother was right to press that ‘cabbage water’ on me. maybe she got her advice from this BMJ paper from 1941.⁴

¹ Disposition of glucosinolates and sulforaphane in humans after ingestion of steamed and fresh broccoli
Conaway, C. C. , Getahun, S. M. , Liebes, L. L. , Pusateri, D. J. , Topham, D. K. W. , Botero-Omary, M. , Chung, F. L. / Nutrition and Cancer, 2000, Vol. 38, No. 2, pp. 168-178, 38 ref.

²Effect of maturity and boiling on glucosinolate content of cruciferous vegetables
Niti Sharma , Swati Bansal / Indian Journal of Nutrition and Dietetics, 2004, Vol. 41, No. 10, pp. 421-425, 17 ref.

³Bitter taste, phytonutrients, and the consumer: a review
Drewnowski, A. , Gomez-Carneros, C. / American Journal of Clinical Nutrition, 2000, Vol. 72, No. 6, pp. 1424-1435, 137 ref.

⁴ The Preparation and Cooking of Green Vegetables.' BRITISH MED. J, 1941 pp. 26-7.

Search CAB Direct (subscribers only) Glucosinolates and cooking

Taking the sting out of nettles

A colleague has just told me that it's 'Be Nice to Nettles Week' - I know it may seem strange to celebrate the merits of such a commonplace plant but the humble nettle has many uses. I have sampled nettle soup and Cornish Yarg wrapped in nettles reputedly to encourage the cheese to ripen (although this also makes the cheese look very attractive). The leaves have a vast number of medicinal uses (once you've got beyond the sting!) whilst fibres from mature stems can be woven into cloth. Nettles are also a good source of natural dyes - green from the shoots and leaves and yellow from the roots.

A quick delve into CAB Abstracts revealed a huge 1080 records on Urtica dioica (an easy Latin name to remember as it really does 'urt when you get stung!) with papers ranging from the use of nettles in medicinal teas and in pig feeds through to increasing biodiversity in your garden.

'Be Nice to Nettles Week' runs from 16-27 May and includes a series of events which start tomorrow.

Disturbing Soil Has Disturbing Effects on Forest Carbon

Forests are seen as a major plank in trying to reduce carbon emissions to mitigate climate change. According to the rules of the Kyoto Protocol and of the United Nations Framework Convention on Climate Change, forestry can generate a sink for greenhouse gases that can contribute to meeting the national commitments to emissions reductions. However, as Robert Jandl of the Austrian Federal Office and Research Center for Forests and his colleagues point out, such as wetlands and peatlands may even be a source of greenhouse gases when they are afforested. How forests are managed also has important effects on how much carbon is absorbed.

Writing in CAB Reviews, Jandl and colleagues described how as part of the IUFRO Task Force on Carbon Sequestration they analysed the effects of harvesting, rotation length, thinning, fertilizer application and tree-species selection on carbon sequestration. All of these have an impact on the forest productivity and consequently on carbon sequestration in the ecosystem. In terms of carbon sequestration and its accounting in national greenhouse-gas budgets, ecosystem stability is highly rated. “Forests that are robust against disturbances up to a certain degree of severity are better suited for political commitments than stands of maximum productivity with a high risk of damages,” say Jandl and his colleagues. “Optimized forest management with regard to soil C sequestration should aim to secure a high productivity of the forest on the input side, and avoid soil disturbances as much as possible on the output side.”

The paper "Carbon sequestration and forest management" by Robert Jandl, Lars Vesterdal, Mats Olsson, Oliver Bens, Franz Badeck and Joachim Rock appears in CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, 2007, 2, No. 017.

Read the full review

Will new parasite hinder UK otter recovery?

Is a new ‘mystery parasite’ likely to stop the recovery of the UK otter population? It appears that we can hope not, but can’t yet be sure. I recently came across a mention in the magazine of the local wildlife trust of such a parasite spreading through otter populations in the south-west of England. The British population of otters (Lutra lutra) has been recovering in recent years, following a decline between the 1950s and the 1970s caused by pesticide pollution and habitat loss, and a new threat would be of concern.

An Internet search revealed that the parasite in question is the gall bladder fluke Pseudamphistomum truncatum, and a search of CAB Abstracts for this species found (as might be expected for a newly introduced species) just two records about its occurrence in the UK (Simpson, V. R. et al.: Veterinary Record (2005) 157 (2), pp. 49-52; Tomlinson, A. and Simpson, V.: Veterinary Record (2006) 158 (2), p. 69); the number of cases reported was small, but the Cornwall Wildlife Trust website (http://www.cornwallwildlifetrust.org.uk) indicates that the Wildlife Veterinary Investigation Centre, where the authors of these papers work, is looking into whether the considerable increase in otter deaths reported in Somerset in 2006 is related to the parasite.

Most of the other articles on P. truncatum come from its main natural range in eastern Europe (from where it is thought to have been introduced to the UK in imported ornamental fish), and report its presence in a variety of host species including otters. Few mention any effect on populations, although a Russian conference paper from 1972 mentions it as one cause of losses of seals (Phoca caspica) in the Caspian Sea, and an article from 1982 reports that these seals had a high prevalence of infection and that infected seals were undernourished and less successful at reproduction. It can be hoped that, if P. truncatum can coexist in eastern Europe with healthy populations of otters of the same species as in the UK, this will be the case elsewhere, but there is always the risk that any pathogen introduced to a new area will become a serious problem, for example if local host populations have low immunity. There is also the potential for P. truncatum infection to spread to pet animals (or even to people if they eat undercooked fish).

The subject of introduced diseases is much too big to discuss in a brief blog entry, but examples where introduced parasites have had significant effects on species of economic or conservation interest include the nematode Anguillicola crassus in European eels, Anguilla anguilla (67 records mentioning both these species in CAB Abstracts since 1998; for an overview see Kirk, R.S.: Fisheries Management and Ecology (2003) 10 (6), pp. 385-394), and avian malaria in native Hawaiian birds (for an overview see Riper, C. van: Bulletin of the Society for Vector Ecology (1991) 16 (1), pp. 59-83). Anyone interested in such diseases, and other invasive species, might like to go to http://www.cabi.org/datapage.asp?iDocID=180 to read about the Invasive Species Compendium that CABI is currently developing.

Insect protein: an alternative to fish meal?

Fish meal and oil are major components of feed for farmed fish, particularly carnivorous species. Fish meal, however, is a finite resource which cannot be produced in sufficient quantities to sustain the current growth in aquaculture; its rising cost is another cause for concern amongst fish farmers. Research into alternatives to fish meal is now an international research priority and is the focus of current fish nutrition research. Promising results have been obtained using plant (soyabean, rapeseed, corn gluten, wheat gluten, pea and lupin meals) and animal (meat meal, meat and bone meal, feather meal and blood meal) byproduct meals. The latest approach, though not new, is the use of insects as a source of protein in fish diets. The nutritive value of insects as feeds for fish, poultry and pigs has been recognised for some time in China where studies have demonstrated that insect-based diets are cheaper alternatives to those based on fish meal. The insects used are the pupae of silkworms (Bombyx mori), the larvae and pupae of house flies (Musca domestica) and the larvae of the mealworm beetle, Tenebrio molitor. Silkworm pupae are an important component of cultured carp diets in Japan and China. Dried ground soldier fly larvae have been fed to chickens and pigs with no detrimental effects [1-2]. In recent years there has been some interest in the use of housefly maggot meal as a substitute for fish meal in tilapia and African catfish diets [3-6]. Bondari and Shepherd [7] observed that channel catfish and blue tilapia fed on soldier fly larvae for 10 weeks were acceptable as food by consumers. Growth and organoleptic quality were not affected when common carp were fed on nondefatted silkworm pupae, a major byproduct of the sericulture industry in India [8]. Ng et al. [9] demonstrated that T. molitor larvae meal was highly palatable to the African catfish (Clarias gariepinus) and could replace up to 40% of the fish meal component without reducing growth performance.

In the March issue of the Journal of the World Aquaculture Society, St-Hilaire and co-workers [10] describe a study in which they determined if black soldier fly (Hermetia illucens) prepupae and housefly pupae could be used as a partial replacement for fish meal and fish oil in rainbow trout (Oncorhynchus mykiss) diets. Their data suggest that a rainbow trout diet in which black soldier fly prepupae or housefly pupae constitute 15% of the total protein has no adverse effect on feed conversion efficiency over a 9-week feeding period. However, rainbow trout fed on black soldier fly diets low in fish oil had reduced levels of omega-3-fatty acids in the muscle. According to the researchers, modifying the diet of the fly larvae could improve digestibility and fatty acid content of the prepupae, which in turn could enhance the fatty acid profile of the fish fed on the fly prepupae.

The use of the black soldier fly in manure management, yields abundant numbers of fly prepupae. The authors of the study suggest that fly prepupae may be an economical and sustainable feed ingredient for carnivorous fish diets. However, before fly prepupae can be used commercially in rainbow trout diets, a larger trial over a longer period should be conducted to confirm their preliminary results.

The CAB Abstracts database contains some 700 records describing research on alternative protein sources for use in aquafeeds.

[1] Newton GL, Booram CV, Barker RW, Hale OM, 1977. Dried Hermetia illucens larvae meal as a supplement for swine. Journal of Animal Science 44:395-400.

[2] Hale OM, 1973. Dried Hermetia illucens larvae (Stratiomyidae) as a feed additive for poultry. Journal of the Georgia Entomological Society 8:16-20.

[3] Adesulu EA, Mustapha AK, 2000. Use of housefly maggots as a fishmeal replacer in tilapia culture: a recent vogue in Nigeria. 5th International Symposium on Tilapia Aquaculture, Rio de Janeiro, Brazil, Fitzsimmons K, Filho JC, eds, Vol. 1, pp. 138.

[4] Ajani EK, Nwanna LC, Musa BO, 2004. Replacement of fishmeal with maggot meal in the diets of Nile tilapia, Oreochromis niloticus. World Aquaculture 35(1):52-54.

[5] Fasakin EA, Balogun AM, Ajayi OO, 2003. Evaluation of full fat and defatted maggot meals in the feeding of clariid catfish Clarias gariepinus fingerlings. Aquaculture Research 34:733-738.

[6] Ogunji JO, Kloas W, Wirth M, Schulz C, Rennert B, 2006. Housefly maggot meal (magmeal): an emerging substitute of fishmeal in tilapia diets. Deutscher Tropentag 2006, Conference on International Agricultural Research for Development, Stuttgart-Hohenheim, Germany, 11-13 October 2006, 7 pp.

[7] Bondari K, Sheppard DC 1987. Soldier fly Hermetia illucens L., as feed for channel catfish, Ictalurus punctatus (Rafinesque) and blue tilapia, (Oreochromis aureus) (Steindachner). Aquaculture and Fisheries Management 18:209-220.

[8] Nandeesha MC, Gangadhara B, Varghese TJ, Keshavanath P, 2000. Growth response and flesh quality of common carp, Cyprinus carpio fed with high levels of nondefatted silkworm pupae. Asian Fisheries Science 13:235-242.

[9] Ng WK, Liew FL, Ang LP, Wong KW, 2001. Potential of mealworm (Tenebrio molitor) as an alternative protein source in practical diets for African catfish, Clarias gariepinus. Aquaculture Research 32: 273-280.

[10] St-Hilaire S, Shepard C, Tomberlin JK, Irving S, Newton L, McGuire MA, Mosley EE, Hardy RW, Sealey W, 2007. Fly prepupae as a feedstuff for rainbow trout, Oncorhynchus mykiss. Journal of the World Aquaculture Society, 38:59-67.

Melamine: important information being ignored?

The saga of the pet food contamination in North America ('The Recall' as it is now being called) rumbles on with some murky new twists. The culprit seems to be a chemical called melamine, an industrial chemical that boosts the nitrogen content of food giving it the appearance of having higher protein content. There are reports from China that feed manufacturers regularly add melamine to animal feeds, and it seems that the melamine in the cat and dog food in the US and Canada came from contaminated of wheat gluten imported from China. It is not clear why Canada (the pet food processor was in Canada), a net exporter of wheat, needs to import a wheat product from China. Melamine has also recently been detected in pig feed and in poultry feed. The pigs and chickens feed the contaminated feed appear to be healthy, but they are being kept under quarantine and are being observed.  The FDA regards to risk to humans from residues of melamine in meat from pigs and chickens to be very low, as the dosage of the chemical would be within the levels considered to be safe.

One interesting aspect of the recall is the lack of published toxicological data on melamine. Another is that some people, science journalists and others, who are writing about melamine toxicity, are ignoring some of the key published information. For example, the New Scientist (5 May 2007, p8) stated that a "literature search shows that the only ill effect of melamine so far identified is its ability to cause bladder cancer in animals given large doses over long periods". In the Guardian Unlimited (4 May) a list of questions and answers on melamine (since withdrawn) stated that "previously the only known risk was to rodents... When fed to male rats in high doses melamine caused tumours". Both of these stories ignored a key paper by R Clark in 1966 which describes poisoning in sheep after being fed melamine for 11 days. The clinical signs included nephrosis with crystals visible in the kidneys in postmortem examination. The abstract of this paper can be seen in the CAB Abstracts archive. Perhaps the journalists only searched Google or PubMed, or the current CAB Abstracts database and so missed this important piece of information. One of the main reasons that CABI decided to digitize its abstract journals was to ensure that users could check the older literature as so many searchers were reluctant to look through the printed archive. The need to search the older material was clearly demonstrated in the case, in 2000, of the a patient in a drug trial at the John Hopkins Hospital who died after being given hexamethonium. The researchers were criticised for not checking the older literature on the drug which would have shown it not to be safe.

The melamine abstract is:

Clark, R. 1966. Melamine crystalluria in sheep. Journal South African Veterinary Medical Assoc., 1966, Vol. 37, pp. 349-351

The toxic effects of melamine given directly or in the feed to merino wethers were studied. A single dose of 100 g increased urea in blood from 28 to 315 mg per 100 ml for a period of 11 days. There was complete loss of appetite and excretion of urine ceased on the tenth day. When the sheep was examined post mortem on the eleventh day the tubules of the kidney were packed with crystals. Nephrosis and erosive abomasitis were seen also. Daily doses of 50 and 25 g killed the sheep after 7 and 9 days, respectively. In those sheep the blood urea was high just before death and post mortem crystals in the kidney tubules, nephrosis, haemorrhagic cystitis and acute typhlitis were seen. The dose of 50 g also caused ulcers in the abomasum. With 10 g daily one sheep did not die but 2 did so after 16 and 31 days. The 2 sheep which died lost appetite and stopped urinating 3 days before death and urea and creatinine in blood then increased sharply. There were crystals in the kidneys and severe oedema of the lungs. In another experiment volume of urine was reduced by offering water freely for 1 h on alternate days. Melamine was mixed with maizemeal and offered to 3 sheep to supply 7 g per sheep per day. All sheep survived for 6 weeks and there was no excessively high value for urea in blood. When daily intake of water was restricted to 600 ml much of the maizemeal containing melamine was refused but the sheep showed no ill effect. The production of white crystals on cooling, the appearance of a white deposit on the addition of picric acid and absorbancy of acidified crystals at 235 m micro indicated the presence of melamine in the urine of treated sheep. Melamine had no effect on pH of contents or motility of rumen and there was no sign of damage to liver.

Cod this mean the end for Gadus morhua?

I was planning a brief summary of cod wars and arguments over fishing zones, but after a little digging I found that many countries, particularly the UK, have been involved in a row over cod fishing at one time or another, and I just don’t have time to go into it all.
So, the point is that the Common Fisheries Policy (CFP) was adopted by the EU in the early 80s and meant that fishing quotas were introduced for member countries.  As new members arrived quotas were quickly used up and, as if to create more arguments over rights, European countries expanded their exclusive fishing zones up to 200 miles offshore.  Also, some European fishermen headed off to the Newfoundland Coast in search of cod and started a row with the Canadians who were likewise struggling with depleted stocks. 
The situation is much more complicated than this, but the point of this blog is that cod is at risk, yet the European Commission is still providing fishing quotas to member countries, against the advice of scientists and environmentalists. 

Cod can live for 20 – 30 years and can grow to over 1.5m long, weighing more than 90 kilos.  Gadus morhua (Atlantic cod) are vulnerable according to the IUCN’s Red List of Threatened Species and are highly exploited.  As for all organisms with indeterminate growth, fecundity increases with body mass and in cod, the number of eggs per female increases with body mass as a power function.  At present the immature fish are unable to reproduce quickly enough to match exploitation.  Instead of a ban on cod fishing, in order to allow stocks to regenerate, quotas have been dished out again (in December 2006 EU ministers only cut cod allowable catch by 14%) and the cod are struggling on.  From the symposium on cod recovery held in Edinburgh in March this year: ‘The Commission believes that reductions in fishing effort and in fishing mortality have been insufficient to achieve cod recovery and that the cod recovery plan must therefore be revised’.  The International Council for Exploration of the Sea (ICES) has called for a complete ban on cod fishing to allow for a recovery plan to take effect, even though plans so far seem to have failed and a ban is highly unlikely.

Patents, pigs and pastoralists

Patents and animal genetic resources make a controversial mix. There are many ethical questions that relate to the patenting of animal genes and whole organisms, genetically modified or not. Some of the most poignant are those addressed in a recent discussion paper published by the League for Pastoral Peoples and Endogenous Livestock Development, entitled 'Patents on animals and their possible impact on smallholder livestock keepers'.

Potential conflict is arising in the Intellectual Property Rights (IPR) arena between the large industrial players operating in the ‘North’ and the pastoral and small-scale livestock farmers of the developing world. At stake, it is argued, are not only livelihoods, but also a large diversity of indigenous livestock breeds and the indigenous knowledge used in their development.

Although at present the USA and EU allow patenting of genetically modified organisms (GMOs), these cannot yet be legally used for food. However, there is increasing pressure from large industrial players to introduce patenting of non-GMOs in livestock production. There are already patents on animals such as that granted by EPO (EP 1330552) on transgenic cows with increased milk production and there has been a recent high profile case of a series of patent applications to 160 countries related, it appears, not only to pig breeding methods, but also to the animals produced by them.

The State of Britain’s Moth Species

The Moth Count Project was launched today by Sir David Attenborough. The project aims to involve thousands of volunteers in monitoring populations of moths through the National Moth Recording Scheme, which is expected to be the largest project of its kind in the world. The hope is that more detailed information will highlight locations where species are struggling so measures to spark recoveries can be taken.

Recent reports by Butterfly Conservation and Rothamsted highlight the demise of these relatives to the much loved butterfly over the past years. Since 1968 moth species across the UK have declined by a third, with the picture being more serious for southern Britain with numbers down by almost 50%.   

Moths are an important and integral part of the British ecosystem and should not be rejected as pests, or even the poor relatives of butterflies. They provide a vital source of food for small mammals and birds, and are an important pollinator of many plant species.

The decline of Britain's moths is blamed on changes in habitat, pesticide use, light pollution and climate change. For example, the garden tiger moth prefers dry winters and has been declining as winter rainfall has increased. It is likely to suffer further from declining numbers and range contractions due to climate change.

Rhubarb, Rhubarb, Rhubarb...

Spring comes & a young man's fancy turns lightly to….RHUBARB..... if he's a fair-weather gardener, that is. If he's a true obsessive, he's probably already harvested his first sticks! Mine are still fighting the battle with the slugs.

Love it or hate it – you’ve got to admit its versatile and easy to grow. Now I knew you could eat it (cooked of course, yum, and so good for those of us on a low GI diet (1), you can clean your burnt pots with it by cooking said rhubarb in them (it's the oxalic acid yah know) and you don’t want to cook it in galvanised iron pots, for fear of poisoning yourself as the acid leaches out the zinc. But now apparently you can use it as an antiseptic mouthwash! (2). Whatever next. Apparently the rhubarb extract is better than yarrow or chamomile but not so effective as straight chlorhexidine, the standard antiseptic in commercial mouthwashes. Still the authors seem encouraged and intend to pursue this line of investigation. I came across this article during "screening": that's the name we editors use for selecting articles for abstracting/indexing in our databases. Of course we also sometimes refer to it as *****. 

The  abstract should be on Global Health by the middle of May, so keep an eye out for it!

So I wondered, what else is on Global Health, Global Health Archive and CAB Abstracts, our  three databases: is rhubarb even more versatile than I thought? Well the rhizomes contain a smooth muscle relaxant (3),  it was used to control post-dysentery diarrhoea in 1st world war hospitals (4), they’ve investigated it as a treatment for lip herpes (5), the anthraquinones in the uncooked roots of Chinese rhubarb, which is used in traditional medicine as a purgative amongst other uses,  can be nephrotoxic (6).

There’s even a paper comparing the pharmacokinetics of oral dosing of rhubarb extract  vs enema (7). Such information is relevant as apparently rhubarb extracts are useful in reducing Blood Urea Nitrogen  in patients with chronic renal failure and may prevent or delay progression to end stage uremic syndrome.

BUT excuse me guys, I’m sticking to mine by mouth.

1. American Journal of Clinical Nutrition, 2002, Vol. 76, No. 1, pp. 281S-285S
2. Majallah i Dandanpizishki (Journal of Islamic Dental Association of Iran), 2006, Vol. 18 No.6, 
    [persian article with english abstract, NOT yet on the database but soon will be]
3. Phytotherapy Research, 2007, Vol. 21, No. 2, pp. 186-189
4. Jl. Roy. Army Med. Corps., 1918, June, Vol. 30, No. 6, pp. 593-394
5. Zeitschrift für Phytotherapie 2005, Vol. 26, No. 6
6. Journal of Ethnopharmacology, 2006, Vol. 107, No. 2, pp. 308-311
7. American Journal of Chinese Medicine, 2005, Vol. 33, No. 6, pp. 839-850