Animal Food Chain Research Articles

No sugar rush [biofuels

The success of biofuels depends on creating a non-food feedstock that produces the right sugar for conversion into fuel. The basic feedstocks for the production of first-generation biofuels are products that would normally enter the animal or human food-chain such as seeds, or grains such as wheat. These crops yield starch that is fermented into bioethanol. The drive is therefore to develop second and third-generation biofuels. Second generation biofuels present the short term solution, and are made up of biofuels derived from feedstock outside the food chain. In the UK the Biotechnology and Biological Sciences Research Council (BBSRC) collaborates to carry out a variety of research to speed up the adoption of second-generation biofuels along the biofuels supply chain.

Selenium concentrations of common weeds and agricultural crops grown in the seleniferous soils of northwestern India

The plants grown in seleniferous soils constitute a major source of toxic selenium levels in the food chain of animals and human beings. Greenhouse and field experiments were conducted to study selenium concentrations of weeds, forages and cereals grown on seleniferous soils located between 31.0417° to 31.2175° N and 76.1363° to 76.4147° E in northwestern India. Eleven winter season (November–April) weed plants were grown in the greenhouse in a soil treated with different levels of selenate-Se. Selenium concentrations of weed plants increased progressively with the levels of selenate-Se in soil. The highest Se concentration was recorded by Silene gallica (246 mg kg − 1 ) and the lowest by Avena ludoviciana (47 mg kg − 1 ) at 2.5 mg Se kg − 1 soil. A . ludoviciana and Spergula arvensis proved highly tolerant to the presence of 1.25 and 2.5 mg selenate-Se kg − 1 soil and the remaining weeds were sensitive to Se. Dry matter yield of Se-sensitive weed plants was 25 to 62% of the yield in the no-Se control at 1.25 mg selenate-Se kg − 1 and 6 to 40% at 2.5 mg selenate-Se kg − 1 soil. Other symptoms like change in leaf colour and size, burning of leaf tips and margins, and delayed flowering were also observed due to Se. Dry matter yield of Se-sensitive weed plants expressed as percentage of yield in the no-Se control at both the Se levels was inversely correlated with their Se content ( r = − 0.731, p < 0.01, N = 17). Among the weed plants grown in seleniferous soils under field situations, Mentha longifolia accumulated the highest Se (365 mg kg − 1 ) and Phalaris minor the lowest (34 mg kg − 1 ). Among agricultural crops grown on a naturally contaminated soil in the greenhouse, Se concentrations were the highest for oilseed crops (19–29 mg kg − 1 ), followed by legumes (6–13 mg kg − 1 ) and cereals (2–18 mg kg − 1 ). Helianthus annuus among the oilseed crops, A . ludoviciana among the winter season weeds, M . longifolia among the summer season (May–October) weeds and Cirsium arvense among the perennial weeds can be used for phytoremediation of seleniferous soils as these accumulate the highest amounts of Se.

Ocorrência de cádmio em produtos à base de cereais, de origem convencional e biológica, destinados à alimentação infantil

Food ingestion is an obvious way of exposure to metals. Cereal foods are an important source of nutrition in the diet of infants and children, and are among the first solid foods eaten. Infants have a more limited diet and consume a higher proportion of their body weight than adults. Cadmium is a toxic metal that occurs naturally in soil, spreading in human and other animal food chain. Due to cadmium content of fertilisers used in conventional farming, there has been a crescent interest in organic products, thought as less harmful to environment and healthier. In the present study, ten samples of both conventional and organic production were analysed for cadmium content using graphite furnace atomic absorption spectroscopy, after dry ashing. All values were under the maximum admissible cadmium content for cereals. Mean cadmium levels were found to range from <1.2 to 9.0 and 9.0 to 69.0 μg/Kg fresh weight in conventional and organic samples, respectively. Cadmium content in organic samples is higher than in conventional ones. Further studies should be performed in order to analyse a larger number and variety of samples, and also to study other conditions that may influence the cadmium content in food.

Soil quality: key for sustainable production

In the last few years several definitions of “soil quality” have been advanced, but among them the most appreciated is “the ability of soils to interact with the ecosystem in order to maintain the biological productivity, the environmental quality and to promote animal and vegetal health” as defined by Doran and Parkin in 1994. Many researchers place more emphasis on its conceptual meaning for land planning and farm management, while others consider that definition to be worth nothing in order to understand soil properties and the concept of soil quality looks like the concept of “to be suitable for”. For this reason a definition of “soil use” is needed. The food quality is characterized by several properties: the healthiness and the nutritional value, the amount of the production, the typicalness and organoleptic properties, etc.. A lot of these properties depend on environmental quality and, in particular, on soil quality. In fact soil represents the natural substrate for growth and productivity of most of the plants that live on the Hearth because they get all the essential nutritional elements from it for their own development; consequently each nutritional element present into the soil as bioavailable form for the plants is potentially destined to entry in the animal (and human) food chain. In the quality process of food productive process it will be important to assure the best soil quality as possible, without any unwanted element (which will not be discussed in this note) and with the right amount of fertility elements in order to guarantee the best production. In this paper the relationships between soil quality, soil biodiversity and crop sustainability will be discussed. Finally the concept of soil “biota” as nodal point for the environment regulation and the application of the indicators for soil quality will be discussed.

Selenium Concentrations of Common Weeds and Agricultural Crops Grown in The Seleniferous Soils of Northwestern India

The plants grown in seleniferous soils constitute a major source of toxic selenium levels in the food chain of animals and human beings. Greenhouse and field experiments were conducted to study selenium concentrations of weeds, forages and cereals grown on seleniferous soils located between 31.0417° to 31.2175° N and 76.1363° to 76.4147° E in northwestern India. Eleven winter season (November–April) weed plants were grown in the greenhouse in a soil treated with different levels of selenate-Se. Selenium concentrations of weed plants increased progressively with the levels of selenate-Se in soil. The highest Se concentration was recorded by Silene gallica (246 mgkg−1) and the lowest by Avena ludoviciana (47 mgkg−1) at 2.5 mg Sekg−1 soil. A. ludoviciana and Spergula arvensis proved highly tolerant to the presence of 1.25 and 2.5 mg selenate-Sekg−1 soil and the remaining weeds were sensitive to Se. Drymatter yield of Se-sensitive weed plants was 25 to 62% of the yield in the no-Se control at 1.25 mg selenate-Sekg−1 and 6 to 40% at 2.5 mg selenate-Sekg−1 soil. Other symptoms like change in leaf colour and size, burning of leaf tips and margins, and delayed flowering were also observed due to Se. Dry matter yield of Se-sensitive weed plants expressed as percentage of yield in the no-Se control at both the Se levels was inversely correlated with their Se content (r=−0.731, pb0.01, N=17). Among the weed plants grown in seleniferous soils under field situations, Mentha longifolia accumulated the highest Se (365 mgkg−1) and Phalaris minor the lowest (34 mgkg−1). Among agricultural crops grown on a naturally contaminated soil in the greenhouse, Se concentrations were the highest for oilseed crops (19–29 mgkg−1), followed by legumes (6–13 mgkg−1) and cereals (2–18 mgkg−1). Helianthus annuus among the oilseed crops, A. ludoviciana among the winter season weeds, M. longifolia among the summer season (May–October) weeds and Cirsium arvense among the perennial weeds can be used for phytoremediation of seleniferous soils as these accumulate the highest amounts of Se.

Prions in Milk from Ewes Incubating Natural Scrapie

Since prion infectivity had never been reported in milk, dairy products originating from transmissible spongiform encephalopathy (TSE)-affected ruminant flocks currently enter unrestricted into the animal and human food chain. However, a recently published study brought the first evidence of the presence of prions in mammary secretions from scrapie-affected ewes. Here we report the detection of consistent levels of infectivity in colostrum and milk from sheep incubating natural scrapie, several months prior to clinical onset. Additionally, abnormal PrP was detected, by immunohistochemistry and PET blot, in lacteal ducts and mammary acini. This PrPSc accumulation was detected only in ewes harbouring mammary ectopic lymphoid follicles that developed consequent to Maedi lentivirus infection. However, bioassay revealed that prion infectivity was present in milk and colostrum, not only from ewes with such lympho-proliferative chronic mastitis, but also from those displaying lesion-free mammary glands. In milk and colostrum, infectivity could be recovered in the cellular, cream, and casein-whey fractions. In our samples, using a Tg 338 mouse model, the highest per ml infectious titre measured was found to be equivalent to that contained in 6 µg of a posterior brain stem from a terminally scrapie-affected ewe. These findings indicate that both colostrum and milk from small ruminants incubating TSE could contribute to the animal TSE transmission process, either directly or through the presence of milk-derived material in animal feedstuffs. It also raises some concern with regard to the risk to humans of TSE exposure associated with milk products from ovine and other TSE-susceptible dairy species.

Effect of irrigation with lake water containing microcystins on microcystin content and growth of ryegrass, clover, rape, and lettuce.

The effect of irrigation with lake water containing a variety of microcystins on accumulation of toxins, or toxin metabolites, and plant growth in ryegrass, clover, rape, and lettuce, was investigated in a glasshouse experiment. The plants were grown in sand culture and received either three or six applications of lake water, which was applied either directly to the sand surface or to the plant shoots. As determined by LC-MS, each plant received 170 mug of a mixture of 10 different microcystins per application. Microcystins in plant samples were extracted with 70% methanol and analyzed by Adda-specific ELISA. For the shoot application treatment, microcystins were not present at measurable levels in shoots of ryegrass or rape, but were present in lettuce [0.79 mg/kg dry weight (DW)] and clover (0.20 mg/kg DW). Total microcystin concentration in roots did not vary greatly depending on whether treatment water was applied directly to the sand, or reached the roots via run-off from the shoots. Microcystins in roots were highest in clover (1.45 mg/kg DW), intermediate in lettuce (0.68 mg/kg DW) and low in ryegrass (0.20 mg/kg DW), and rape (0.12 mg/kg DW). There was no evidence for root-to-shoot translocation of microcystins. Three applications of microcystins reduced shoot DW of ryegrass, rape and lettuce, and increased root DW of ryegrass and lettuce. Clover DW was not changed by treatment with microcystins. The results show that irrigation with water containing microcystins has the potential to move microcystins into farm animal and human food chains at concentrations that can exceed recommended tolerable limits.

Emerging Fusarium -Mycotoxins Fusaproliferin, Beauvericin, Enniatins, And Moniliformin—A Review

The contamination of foods and feed with mycotoxins is a commonly known problem. Intense investigations have been conducted to study the occurrence, toxicity, and recently also the prevention and detoxification strategies of mycotoxins in human and animal food chains. Most of the studies have emphasized on “traditional” mycotoxins, such as aflatoxins, ochratoxin A, and trichothecenes. However, one of the most common grain-contaminating genus of fungi, Fusarium spp., is also capable of producing other toxic secondary metabolites—the so-called emerging mycotoxins such as fusaproliferin, beauvericin, enniatins, and moniliformin. So far, only limited data is available on these metabolites. This is not only due to their late recognition but especially the late understanding of their role as mycotoxins. This paper summarizes the existing data on the chemistry, analytical techniques, biosynthesis, production, toxicity, and occurrence data on fusaproliferin, beauvericin, enniatins, and moniliformin. Based on the available studies, attention should be paid to the studies on the distinct signifigance of these compounds in the human and animal food chains.

Proceedings of the International Symposium on Selenium–Mercury Interactions

Mercury is a rare but ubiquitous element that is found in trace amounts in practically all soils, minerals, plants, bodies of water, and, because the element and some of its compounds are volatile, in the air. It is estimated that, annually, approximately 40,000 tons of mercury are released into the atmosphere from the Earth’s surface, 4,000 tons from volcanic eruptions, 5,000 tons through the burning of fossil fuels, and 3,000 tons from rivers and glaciers. Through bacterial action, mercury is partially converted to methyl mercury. Much of the mercury released eventually reaches the oceans and, through various biological and geochemical processes, ends up in oceanic sediments. It is, thus, not surprising that practically all ocean fish contain some mercury and methyl mercury in their organs and tissues. Because mercury and, especially, methyl mercury are toxic, public concerns about the safety of seafood have been raised. However, the evidence of harm by the mercury in fish to humans is scant and leading nutrition experts have in fact concluded that the health benefits of seafood, if only as nutritional sources of omega-3 fatty acids, greatly outweigh any potential risk associated with the presence of mercury. In discussing mercury toxicity, the fact that organisms have developed physiological mechanisms of mercury detoxification is also often ignored. An efficient mechanism of mercury detoxification involves its reaction with selenium. Selenium is an essential trace element needed for many important physiological processes. Like mercury, it is transported along the hydrological cycle and reaches the oceans where it combines with mercury under reducing conditions to form the highly insoluble mercury (II) selenide, which ends up in marine sediments. Because selenium is more abundant than mercury, not all of the oceanic selenium is trapped by mercury. Enough selenium remains to be taken up by plankton and other organisms in the food chain of marine animals. As a rule, ocean fish obtain enough selenium for their physiological needs and for the detoxification of the mercury they may come in contact with. Humans likewise detoxify Biol Trace Elem Res (2007) 119:193–194 DOI 10.1007/s12011-007-8008-4

Uptake of perchlorate by vegetation growing at field sites in arid and subhumid climates

AbstractPrevious greenhouse and field studies show that terrestrial and aquatic vegetation, including trees, grasses, and agricultural produce grown on perchlorate‐contaminated soil or with perchlorate‐contaminated irrigation water, accumulate perchlorate mainly in their leaf tissue. The phytoaccumulated perchlorate poses potential ecological risk by either contaminating the food chain of humans and animals or recycling in the ecosystem as leaf litter fall that accumulates on topsoil. In this study, the uptake and phytoaccumulation of perchlorate in terrestrial and aquatic vegetation growing at two perchlorate‐contaminated sites (the Longhorn Army Ammunition Plant [LHAAP] in Karnack, Texas, and the Las Vegas Wash [LVW], Nevada) was monitored during multiple growing seasons. The LHAAP site is located in a subhumid climate, while the LVW site is located in an arid climate. All vegetation species collected from both sites contained quantifiable levels of perchlorate. The detected concentrations varied with the type of plant species, amount of perchlorate concentration in soil, and season and stage of plant maturity. The highest perchlorate concentrations were measured in willows (Salix nigra), crabgrass (Digitaria spp.), and Bermuda grass (Cynodon dactylon) at the LHAAP, while salt cedar (Tamarix ramosissima) at the LVW phytoaccumulated the highest mass of perchlorate. The concentrations of perchlorate measured in plant leaves growing over contaminated soils at multiple LHAAP locations did not reveal the strong seasonal variability observed at the LVW site. The slow rate of phytodegradation of the perchlorate fraction taken up by plants during the growing season explained the detection of higher perchlorate concentrations in leaves collected later in the growing season (fall) and in senesced leaves compared to younger, live leaves. This proves that senesced plant leaves potentially recycle perchlorate back into the soil on which plant litter collects. To minimize the potential recycling of perchlorate during phytoremediation, it is recommended that senesced leaves be collected and composted or phytoremediation be designed to enhance rapid rhizodegradation (rhizoremediation). © 2007 Wiley Periodicals, Inc.

Containment of regulated genetically modified cotton in the field

Genetically modified (GM) insect and herbicide resistant cottons are now the mainstay of the cotton industry based in the eastern States of Australia. However, during the early years of breeding and seed increase, there was some uncertainty among regulators about containment measures needed to prevent the movement of regulated GM traits into adjacent fields of conventional cotton and possibly into the human or animal food chain. This was particularly relevant in the more tropical north of Australia that was being used as a winter nursery. Field experiments on GM cottons in eastern Australia were commonplace, but even there, regulators required confirmation that the containment practices already in place (buffer zones and isolation distances) were effective. A series of experiments in a range of environments, designed to monitor the movement of GM pollen into adjacent cotton buffers, adjacent fields, across bare ground and over long distances are reported here. Gene flow from GM plots into adjacent conventional cotton was found to be much higher in northern Australia than in eastern Australia, most likely due to higher honey bee ( Apis mellifera) numbers, often deliberately enhanced to aid the surrounding horticultural industries. Movement of pollen over bare ground to nearby crops was observed at a number of locations indicating that small isolation zones should not be used for containment of regulated GM cotton. In general, buffers of 20 m of conventional cotton surrounding GM plots proved to be highly effective unless bee numbers were artificially high. Based on insect observations and rates of pollen flow, it was concluded that pollen beetles ( Carpophilus spp.), another potential pollen vector normally highly abundant in cotton, were not associated with movement of pollen more than 1 m away from crops.

Genetically modified potato plants in nutrition and prevention of diseases in humans and animals: a review

Genetically modified organisms (GMO) become a real constituent of our lives and nowadays, they are commonly introduced into the food chain of people and animals in some states. Among higher organisms, plants are used above all for genetic modifications; potatoes are a suitable model plants for this purpose. Nowadays, a number of various genetic modifications of potato plants are available, particularly those with increased resistance to biological agents and factors of the external environment or with improved nutritional value. Plants that produce proteins of the immune system of man or animals or substances that may be used as vaccines in human or veterinary medicine are highly important. Modified potato plants that produce biomaterials for potential applications in the industry are a significant category.

On the Question of Sporadic or Atypical Bovine Spongiform Encephalopathy and Creutzfeldt-Jakob Disease

Strategies to investigate the possible existence of sporadic bovine spongiform encephalopathy (BSE) require systematic testing programs to identify cases in countries considered to have little or no risk of orally acquired disease or to detect a stable occurrence of atypical cases in countries in which orally acquired disease is disappearing. To achieve 95% statistical confidence that the prevalence for sporadic BSE is no greater than 1 per million (i.e., the annual incidence of sporadic Creutzfeldt-Jakob disease [CJD] in humans) would require negative tests in 3 million randomly selected older cattle. A link between BSE and sporadic CJD has been suggested on the basis of laboratory studies but is unsupported by epidemiologic observation. Such a link might yet be established by the discovery of a specific molecular marker or of particular combinations of trends over time of typical and atypical BSE and various subtypes of sporadic CJD, as their numbers are influenced by a continuation of current public health measures that exclude high-risk bovine tissues from the animal and human food chains.

Influence of processing on trichothecene levels

Trichothecene mycotoxins frequently occur in cereal grains that are intended for food production. The process of converting grains into food and drinks for consumers has significant effects on the levels of toxins in the final food. Surveillance of retail food and drinks of cereal origin demonstrates that trichothecenes do survive the production processes employed. Trichothecenes are relatively heat stable chemicals, with high water solubility, properties that affect their processing fate. It is known that the extent of transmission into final food products is dependent on the pattern of Fusarium infection in the grains. For dry-milled products, the most highly contaminated fractions are those that contain the whole or the outer portions of the grain. For wet milling, the trichothecenes primarily transfer to the aqueous fractions, the most contaminated streams enter the animal food chain, although there is no evidence of significant trichothecenes transmission into animal products. However, anomalies remain in the understanding of the processing effects of several major cereal processes used in European food production (e.g. baking and brewing).

Bovine spongiform encephalopathy.

Early epidemiological studies identified bovine spongiform encephalopathy as a feed-borne infection associated with infected meat-and-bone meal in animal feed. The infection may have derived from scrapie in sheep, a spontaneous genetic mutation in cattle, or a transmissible spongiform encephalopathy in another mammalian species. Experimental work on the risk of transmission has necessarily tried to identify risk materials and their infectivity levels, the nature and size of species barriers, the infectious dose, the route of infection, the strain of the agent and the genotype of the animals at risk. The identification of levels of infection in cattle tissues has aided the removal of risk materials from the human and animal food chains. Maternally associated transmission is unlikely to maintain an outbreak, but the offspring of clinical cases appear to be at greater risk when the rate of food-borne exposure is high. Studies of embryo transfer have not shown infection to be transmitted by this means. While the control measures appeared to be straightforward, compliance has at times proved difficult to enforce and quantify. This has necessitated more extensive prohibitions, aggressive enforcement and thorough auditing of compliance levels.

Les risques alimentaires liés aux agents transmissibles non conventionnels (ATNC)

Transmissible spongiform encephalopathy (TSE) agents also named prions are responsible for transmissible subacute spongiform encephalopathies in humans and animals. TSE agents are thought to be composed only of an abnormal isoform of a host-coded protein, the prion protein (PrP). In vivo, raise in infectivity titer is always associated with a proportional accumulation of PrP. Aminoacid sequences of PrP obtained from normal and infected brains are identical, and these two proteins differ only by their biochemical and biophysical behaviour: in particular, PrP from TSE-affected individuals resists to proteinase K digestion. PrP-c is the PrP found in normal individuals, PrP-res is the proteinase K resistant PrP identifiable in infected individuals. TSE agents are capable to cross the species barrier. In march 96, a new variant of Creutzfeldt-Jakob disease (vCJD) has been described in UK. This emerging disease is now recognized to be induced by the BSE agent. Protection of human health is ensured by systematic PrP-res screening of cattle at slaughterhouse and by the specified risk material ban in the human and animal food chain.

Diagnosis and prevention of bovine spongiform encephalopathy and variant Creutzfeldt-Jakob disease.

An outbreak of bovine spongiform encephalopathy (BSE) arose in the United Kingdom as a result of prions entering and being recycled through the ruminant food chain. Humans have since developed a variant form of Creutzfeldt-Jakob disease (vCJD), also mostly in the United Kingdom, that occurs in younger individuals and causes prominent psychiatric and/or behavioral manifestations early in disease. Laboratory studies now provide strong evidence that the causative agent of BSE in cattle and vCJD in humans share a common origin. Because of a lack of information regarding the incubation period of vCJD and the number of people who may have been exposed, the future scope of this disease remains unknown. Control of the current and any future outbreaks in cattle requires strict measures to prevent contamination of the animal food chain with prions of any species. Prevention of human exposure mandates the avoidance of neural tissue in all human foods.

Antibiotic resistance genes back in the food chain

Genes resistant to tetracycline have been found in groundwater as far as 250 m downstream from two swine facilities that use antibiotics as growth promoters. The finding is significant because it shows the potential for spreading resistance back into the food chain of animals and people, say researchers from the University of Illinois and Illinois State Geological Survey. Using standard PCR, they analyzed samples from lagoons, wells and groundwater on and near two Illinois facilities. The researchers could identify the trail taken by the resistance genes as the DNA in the samples matched the resistance genes previously identified in livestock and feed. [Chee-Sanford, J.C. et al. (2001) Appl. Env. Microbiol. 67, 1494–1592] PL

Behavior of sewage sludge-derived PAHs on pasture.

A field experiment was set up to investigate the retention of PAHs by pasture grass following sludge application. In addition to information on compound-specific loss rates, the influence of meteorological variables and sludge-pasture contact time on the weathering process were investigated. The rates of loss were compound specific with half-lives ranging from < 1 to 10 d. The lighter PAHs were rapidly lost from the grass surface primarily by volatilization. For the intermediate and heavier PAHs, loss was slower with rain playing an important role in the weathering process. Growth dilution was also important in reducing the contaminant levels in the grass. The effect of sludge-pasture contact time prior to weathering by rain on the residual levels remains unclear. In terms of risk of exposure, there is the potential for persistent organic contaminants to be introduced into the grazing animal food chain if sewage sludge is applied to pasture land.

Impact of synthetic pyrethroid-sheep dip on the indigenous microflora of animal slurries.

The chemical constituents of sheep dip in the UK are currently changing from organophosphate-based to synthetic pyrethroid-based insecticides. As a result, changes are also being made to the methods of disposal of these chemicals in the environment, such that pyrethroid sheep dips must now be diluted in animal slurry or water. To date, there is a lack of quantitative information on the impact of the insecticide on the indigenous microflora of animal slurries. This paper investigated the impact of Bayticol (synthetic pyrethroid sheep dip) over a range of concentrations on selected populations of bacteria within animal slurry. It was found that, with increasing pesticide concentration, there was up to a four orders of magnitude increase in the numbers of faecal coliforms and pathogens, such as putative Salmonella spp. These findings have implications for the disposal of sheep dip-amended animal slurries to land from several aspects: (i) the longevity of putative pathogens in the field may require re-evaluation of the time required before the return of grazing livestock to a slurry-amended field; (ii) the potential for the transfer of pathogenic bacteria and faecal coliforms into human and animal foodchains, and (iii) the increased potential for faecal coliforms being washed into streams, rivers and coastal bathing waters.