Feeding of palm oil fatty acids or rapeseed oil throughout lactation: Effects on mammary gene expression and milk production in Norwegian dairy goats.

Lipid added as rapeseed or palm oil to the diet of dairy goats over 8 mo of one lactation alters fat secretion and milk fatty acid (FA) and protein composition. In this study, we examined the contribution of mammary gene expression to these changes and included 30 multiparous goats of Norwegian dairy goat breed for a 230-d experimental period, with indoor feeding from 1 to 120 d in milk (DIM), mountain grazing from 120 to 200 DIM, and indoor feeding from 200 to 230 DIM. After an initial period (1-60 DIM) when the control diet was given to all goats, the animals were subdivided into 3 groups of 10 goats. Treatments (60-230 DIM) were basal concentrate (control) alone or supplemented with either 8% (by weight) hydrogenated palm oil enriched with palmitic acid (POFA) or 8% (by weight) rapeseed oil (RSO). Milk was sampled individually from all animals throughout lactation, at 60, 120, 190, and 230 DIM for milk yield and composition. On d 60, 120, 190, and 230, mammary tissue was collected by biopsy to measure mRNA abundance of 19 key genes. None of the 19 genes involved in milk protein, apoptosis, lipid metabolism, transcription factors, and protein of the milk fat globule membrane, as measured by mRNA abundance, were affected by the lipid supplements, although POFA increased milk fat content, and POFA and RSO affected milk FA composition. Over the experimental period (120-230 DIM), the mRNA abundance of 13 of the 19 studied genes was affected by lactation stage. For some genes, expression either gradually increased from 120 to 230 DIM (CSN2, CASP8, CD36, GLUT4) or increased from 120 to 200 and then remained stable (XDH), or decreased (CSN3, G6PD, SREBF1, PPARG1) or increased only at 230 DIM (SCD1, SCD5, ELF3). For a second group of genes (CSN1, LALBA, FABP3, FASN, LPL, MFGE8), expression was stable over the lactation period. Our results suggest that factors other than gene expression, such as substrate availability or posttranscriptional regulation of these genes, could play an important role in the milk fat and FA responses to dietary fat composition in the goat. In conclusion, mammary gene expression in goats was more regulated by stage of lactation than by the dietary treatments applied.

Feeding of palm oil fatty acids or rapeseed oil throughout lactation: Effects on energy status, body composition, and milk production in Norwegian dairy goats.

The objective of this experiment was to examine how supplements of rapeseed oil or palm oil fatty acids would affect milk production and composition, body lipid stores, and energy balance in 30 multiparous goats of Norwegian dairy goat breed. The experiment lasted 230 d, with 1 to 120 d in milk (DIM) for indoor feeding (P1), 120 to 200 DIM for mountain grazing (P2), and 200 to 230 DIM for indoor feeding (P3). Grass silage was fed according to appetite during indoor feeding periods. After an adjustment period (1-60 DIM) when the control diet was given to the goats, the animals were subdivided into 3 groups of 10 goats. Treatments (60-230 DIM) were (1) basal concentrate (control; no added fat); (2) control concentrate with 8% (added on air-dry basis) hydrogenated palm oil enriched with palmitic acid (POFA); and (3) control concentrate with 8% (added on air-dry basis) rapeseed oil (RSO). Individual energy balances based on energy intake and milk production were estimated on 10, 30, 60, 90, 120, 200, and 230 DIM. At the same times, body weight (BW), body condition score (BCS), body mass index, and body tissue stores using computed tomography were monitored. Silage intake was depressed by POFA throughout the experimental period. Reduced BW and body mass index were observed in the POFA and RSO groups, whereas no effect on BCS or body composition was observed throughout lactation. Generally, a minor decrease in BW was observed from 10 to 120 DIM (only 0.6 kg on average) and the total amount of body lipid was reduced by 4.4 kg. During the mountain grazing period, a further reduction in body lipid stores (2.7 kg) was observed, and BW was reduced by 3.9 kg in the same period. The goats mobilized, on average, 72% of their fat reserves during the first 200 DIM. In this period, dietary fat supplementation did not reduce the mobilization of adipose tissue but resulted in greater milk fat yield (2 kg more, on average, compared with the control group). Milk yield was not affected by POFA or RSO supplementation. Milk fat content was higher in the POFA group than in the control and RSO groups. Milk protein and lactose contents were not affected by lipid supplements. In late lactation, a rapid accumulation of fat deposits followed the intense mobilization during the grazing period. Dietary lipid supplements had no effect on milk fat yield at this stage. Milk production depends heavily on the ability to mobilize body lipid stores, and neither POFA nor RSO supplements at rates used in our study affected this mobilization.

Effects of 12 weeks' treatment with a proton pump inhibitor on insulin secretion, glucose metabolism and markers of cardiovascular risk in patients with type 2 diabetes: a randomised double-blind prospective placebo-controlled study.

AIMS/HYPOTHESIS: Recent studies suggest that proton pump inhibitor treatment may increase insulin secretion and improve glucose metabolism in type 2 diabetes. In a randomised double-blind prospective placebo-controlled 2 × 2 factorial study, we examined the effect of esomeprazole on insulin secretion, HbA(1c) and cardiovascular risk factors in type 2 diabetes. METHODS: Forty-one patients with type 2 diabetes using dietary control or oral glucose-lowering treatment were randomised to receive add-on esomeprazole 40 mg (n = 20) or placebo (n = 21) for 12 weeks. Randomisation was carried out prior to inclusion on the basis of a computer-generated random-number list. The allocation sequence was concealed in sealed envelopes from the researcher enrolling and assessing participants. The study was undertaken at Steno Diabetes Center, Gentofte, Denmark. The primary outcome was change in AUC for insulin levels during a meal test. Secondary outcomes were the levels of HbA(1c) and biochemical markers of cardiovascular risk, including lipids, coagulation factors, inflammation markers, markers of endothelial function and 24 h ambulatory BP measurements. RESULTS: Forty-one participants were analysed. In the esomeprazole-treated group the AUC for insulin did not change (before vs after treatment: 28,049 ± 17,659 vs 27,270 ± 32,004 pmol/l × min (p = 0.838). In the placebo group AUC for insulin decreased from 27,392 ± 14,348 pmol/l × min to 22,938 ± 11,936 pmol/l × min (p = 0.002). Esomeprazole treatment (n = 20) caused a ninefold increase in the AUC for gastrin. HbA(1c) increased from 7.0 ± 0.6% (53 ± 5 mmol/mol) to 7.3 ± 0.8% (56 ± 6 mmol/mol) in the esomeprazole-treated group and from 7.0 ± 0.6% (53 ± 5 mmol/mol) to 7.4 ± 0.8% (57 ± 6 mmol/mol) in the placebo group (n = 21) (p for difference in change >0.05). Except for BP, there were no differences between the groups in the markers of cardiovascular risk (p > 0.05). Monitoring of 24 h ambulatory BP showed a significant decrease in daytime systolic BP, daytime diastolic BP and 24 h diastolic BP in the placebo group (p < 0.05). No change in BP was seen in the patients treated with esomeprazole. CONCLUSIONS/INTERPRETATION: Treatment with esomeprazole over 12 weeks did not improve insulin secretion, glycaemic control or cardiovascular disease biomarkers in patients with type 2 diabetes.

Treatment with a proton pump inhibitor improves glycaemic control in Psammomys obesus, a model of type 2 diabetes.

AIMS/HYPOTHESIS: Gastrin has been implicated in islet growth/neogenesis, and proton pump inhibitors (PPIs) have been shown to increase endogenous gastrin levels in animals and humans. Therefore, we investigated the effect of PPIs in a model of type 2 diabetes, Psammomys obesus. METHODS: P. obesus (morning blood glucose [mBG] 16.9 +/- 0.6 mmol/l) were treated with vehicle or different doses (1-15 mg/kg) of lansoprazole for 17 days. RESULTS: Treatment with lansoprazole resulted in up to ninefold dose-dependent increases in endogenous gastrin levels (p < 0.05 for 10 mg/kg lansoprazole vs vehicle). There was a significant reduction in mBG levels in all animals in the high-dose lansoprazole groups during the 17 day treatment period, whereas there was no significant improvement in mBG in animals in the vehicle groups. The mBG at end of study was 18.2 +/- 2.1, 8.7 +/- 2.2 (p < 0.01), and 6.1 +/- 2.3 (p < 0.001) mmol/l for vehicle and lansoprazole 10 and 15 mg/kg, respectively. The animals treated with 15 mg/kg lansoprazole, compared with vehicle, had a 2.3-fold increase in the intensity of insulin staining in beta cells (p=0.0002) and 50% higher beta cell mass (p=0.04). CONCLUSIONS/INTERPRETATIONS: The PPI lansoprazole had significant glucose-lowering effects in an animal model of type 2 diabetes, an effect that is most likely mediated through an increase in endogenous gastrin levels.

Effects of 12 weeks of treatment with fermented milk on blood pressure, glucose metabolism and markers of cardiovascular risk in patients with type 2 diabetes: a randomised double-blind placebo-controlled study.

OBJECTIVE: Studies have indicated a blood pressure (BP)-lowering effect of milk-derived peptides in non-diabetic individuals, but the cardiometabolic effects of such peptides in patients with type 2 diabetes (T2D) are not known. We investigated the effect of milk fermented with Lactobacillus helveticus on BP, glycaemic control and cardiovascular risk factors in T2D. DESIGN: A randomised, double-blinded, prospective, placebo-controlled study. METHODS: In one arm of a factorial study design, 41 patients with T2D were randomised to receive 300 ml milk fermented with L. helveticus (Cardi04 yogurt) (n=23) or 300 ml artificially acidified milk (placebo yogurt) (n=18) for 12 weeks. BPs were measured over 24-h, and blood samples were collected in the fasting state and during a meal test before and after the intervention. RESULTS: Cardi04 yogurt did not reduce 24-h, daytime or nighttime systolic or diastolic BPs compared with placebo (P>0.05). Daytime and 24-h heart rate (HR) were significantly reduced in the group treated by Cardi04 yogurt compared with the placebo group (P<0.05 for both). There were no differences in HbA1c, plasma lipids, C-reactive protein, plasminogen activator inhibitor-1, tumour necrosis factor alpha, tissue-type plasminogen activator: Ag, and von Willebrand factor: Ag between the groups. The change in fasting blood glucose concentration differed significantly between the two groups with a larger increase in the placebo group (P<0.05). CONCLUSIONS: Ingestion of milk fermented with L. helveticus compared with placebo for 12 weeks did not significantly reduce BP in patients with T2D. Our finding of lower HRs and fasting plasma glucose levels in T2D patients during ingestion of fermented milk needs further validation.

Infusions of parathyroid hormone in ruminants: hypercalcemia and reduced plasma 1,25-dihydroxyvitamin D concentrations.

The relationship between infused synthetic bovine PTH-(1-34) and plasma concentrations of minerals and vitamin D metabolites was studied in eight calves (150-230 kg) and two thyroparathyroidectomized goats. Calves were infused iv with saline for 15-20 h. Then, calves were infused with one of three types of solution for an additional 35-h period. Three of the eight calves received 3 ng/kg X min (group H), three received 0.75 ng/kg X min (group L), and the remaining two calves received control saline over a 33-h period (group C). Blood samples were taken every 4-6 h. Plasma calcium, phosphorus, hydroxyproline, and 1,25-dihydroxyvitamin D [1,25-(OH)2D] remained relatively constant in control calves. PTH infusions into calves in group H resulted in an increase in plasma calcium from 2.4 to a plateau of 3.0 mmol/liter. PTH infusion caused no change in plasma phosphorus, but increased urinary excretion of phosphorus. Infusion of PTH caused a moderate increase in urinary calcium excretion, followed by pronounced calciuria after PTH withdrawal. Plasma concentrations of 1,25-(OH)2D decreased from about 30 pg/ml at the start of infusion to undetectable levels (less than 5 pg/ml) at the end of the infusion and for 30 h thereafter. Similar, but less pronounced, changes in plasma calcium and 1,25-(OH)2D concentration were observed in group L. Hypocalcemia and hypophosphatemia developed in the two lactating goats after thyroparathyroidectomy, and plasma 1,25-(OH)2D concentrations were decreased. PTH infusion (3 ng/kg X min) corrected the hypocalcemia and hypophosphatemia and markedly raised plasma 1,25-(OH)2D concentrations. When calcium chloride was infused in addition to PTH, the resulting hypercalcemia (3 mmol/liter) was associated with a marked reduction in plasma 1,25-(OH)2D. We conclude that the concentration of calcium in plasma has the major regulatory role on plasma 1,25-(OH)2D concentrations in ruminant species when potentially conflicting signals, such as hypercalcemia and high PTH concentrations, are present simultaneously.

A permanent preparation allowing measurements of secretion of parathyroid hormone in conscious goats.

A preparation for estimations of rates of secretion of parathyroid hormone (PTH) in conscious goats is described. The procedure involved surgical isolation of a thyroid with its indwelling parathyroid gland, leaving the blood supply intact. Permanent access to the arterial and venous supplies of the preparation was secured by exteriorization of the jugular vein and carotid artery in skin-covered loops. The remaining parathyroids were removed leaving the isolated parathyroid gland as the only source of the hormone. For the seven goats operated on, the preparation has worked satisfactorily from the start in five and also in the remaining two after a reoperation to cut an accessory venous drainage. The loops have been catheterized repeatedly for extended periods of time and the preparation has proved useful for periods of up to 3 years. Secretion of PTH was measured in one goat at two consecutive parturitions. In late pregnancy, secretion rates of 0.7-0.9 ng/kg per min were observed when the dietary calcium intake was adequate. In the first weeks of lactation, secretion increased to 1.2-1.5 ng/kg per min when the intake of calcium was adequate and to 2.0-2.2 ng/kg per min when calcium intake was inadequate. Reductions in calcium intake led to increased rates of secretion of PTH both during pregnancy and during lactation. The results indicate that the preparation may be useful in the study of changes in PTH secretion both acutely and in connection with long-term studies of dietary adaptations of the calcium metabolism.

Maintenance of secretion of calcium and magnesium during infusions of parathyroid hormone to lactating goats.

Hourly secretion of calcium and magnesium by goat mammary glands was studied following infusions of bovine parathyroid hormone (PTH) into the mammary artery in amounts (6-15 ng/kg per min) giving rise to levels of PTH in mammary venous blood commonly observed during spontaneous hypocalcaemia (2.4-13 micrograms/l). In two series of experiments a 3 h infusion of PTH was given. The first series was carried out at a normal level of plasma calcium, while the availability of calcium was increased by a 20 h infusion of CaCl2 in the other series. No changes in mammary secretion of calcium or magnesium could be observed during the hormone infusions. A decrease in the urinary excretion of calcium occurred, thus demonstrating the activity of the infused PTH. In a third experiment an 18.5 h infusion of PTH (6 ng/kg per min) into the mammary artery was given to study possible effects of a more prolonged increase of PTH concentrations. This infusion caused a gradual increase in plasma levels of calcium. Average concentrations of calcium in milk increased slightly (about 5%) in both glands (P less than 0.05). The hourly yield of milk was not significantly changed in the infused gland after 18.5 h of PTH infusion. A small but significant increase occurred in the non-infused gland. Yields of magnesium were not influenced by the infusion of PTH. It was concluded that losses of calcium into milk are independent of the PTH concentration in the circulation.

The amylin analog pramlintide improves glycemic control and reduces postprandial glucagon concentrations in patients with type 1 diabetes mellitus.

To explore further the effects of the human amylin analog pramlintide on overall glycemic control and postprandial responses of circulating glucose, glucagon, and metabolic intermediates in type 1 diabetes mellitus, 14 male type 1 diabetic patients were examined in a double-blind, placebo-controlled, crossover study. Pramlintide (30 microg four times daily) or placebo were administered for 4 weeks, after which a daytime blood profile (8:30 AM to 4:30 PM) was performed. Serum fructosamine was decreased after pramlintide (314+/-14 micromol/L) compared with placebo (350+/-14 micromol/L, P = .008). On the profile day, the mean plasma glucose (8.3+/-0.7 v 10.2+/-0.8 mmol/L, P = .04) and postprandial concentrations (incremental areas under the curve [AUCs] from 0 to 120 minutes) were significantly decreased during pramlintide administration (P < .01 for both) despite comparable circulating insulin levels (359+/-41 v 340+/-35 pmol/L). Mean blood glycerol values were reduced (0.029+/-0.004 v 0.040+/-0.004 mmol/L, P = .01) and blood alanine levels were elevated (0.274+/-0.012 v 0.246+/-0.008 mmol/L, P = .03) after pramlintide versus placebo. Blood lactate concentrations did not differ during the two regimens. During pramlintide administration, the AUC (0 to 120 minutes) for plasma glucagon after breakfast was diminished (P = .02), and a similar trend was observed following lunch. In addition, peak plasma glucagon concentrations 60 minutes after breakfast (45.8+/-7.3 v 72.4+/-8.0 ng/L, P = .005) and lunch (47.6+/-9.0 v 60.9+/-8.2 ng/L, P = .02) were both decreased following pramlintide. These data indicate that pramlintide (30 microg four times daily) is capable of improving metabolic control in type 1 diabetics. This may relate, in part, to suppression of glucagon concentrations. Longer-term studies are required to ascertain whether these findings are sustained over time.

Effects of hyperinsulinaemia and hypoglycaemia on circulating leptin levels in healthy lean males.

Current knowledge of the regulatory mechanisms of leptin synthesis and release is limited. To elucidate the role of short-term hyperinsulinaemia and hypoglycaemia on circulating levels of leptin, 7 healthy lean men underwent a 360-min hyperinsulinaemic (insulin infusion rate: 1.5 mU/kg/min) clamp in two conditions: (i) during 360 min of euglycaemia and (ii) during 120 min of euglycaemia followed by 240 min of graded hypoglycaemia (nadir 2.9 +/- 0.1 mmol/l). During hyperinsulinaemic euglycaemia, serum leptin levels were initially stable and then rose gradually after 180 min to a peak value of 147 +/- 7% of baseline (ANOVA, p < 0.01). During the hypoglycaemic clamp, the leptin profile differed from that of euglycaemic conditions (p < 0.01) since the increase was postponed and reduced. In both clamp studies, leptin dynamics contrasted with the changes in a control study performed in 7 other men whose serum leptin fell significantly (p < 0.05) to 77 +/- 4% of baseline values during a 360-min fast (following overnight fasting). It is concluded that hyperinsulinaemia for more than 3 h increases circulating levels of leptin in lean males, whereas hyperinsulinaemia with concomitant hypoglycaemia leads to transient suppression. The exact nature of the underlying mechanisms, e.g. changes in levels of insulin, glucose, various substrates, glucose turnover and/or counterregulatory hormones, remains to be determined.

Chemical methods for reduction of the transfer of radionuclides to farm animals in semi-natural environments.

The same chemicals can be used for reduction of radionuclide transfer to animals whether kept on farms or grazing in semi-natural and natural habitats. However, different techniques are required for administration of the active compounds. Dairy ruminants may be treated effectively by inclusion of chemicals in supplemental concentrates. Practical experience gained after the Chernobyl accident has shown that both clay minerals and hexacyanoferrates are effective in preventing high radiocaesium levels in animal products. Chemicals such as bentonite clays and CaCO3, used for reduction of 137Cs and 90Sr transfer respectively, must be fed in hectogram quantities and are only practical for dairy animals in semi-natural ecosystems. Salt licks and sustained release boli with hexacyanoferrates as caesium binders have been developed and used successfully after the Chernobyl accident for meat producing cattle, sheep and reindeer which graze freely for extended periods. Daily doses of 25-300 mg in sheep and 250-2000 mg in cows reduces 137Cs accumulation 2-10-fold. Binders for 90Sr have not been tested in grazing animals. Stable iodine could be provided in salt licks and indwelling rumen boli at rates required to block radioiodine uptake by the thyroid gland. Boli and salt licks are highly cost effective in reducing doses to man when compared to interdiction of food from farm animals.

Countermeasures for reducing radioactive contamination of farm animals and farm animal products.

A summary is given of the range and effectiveness of different available countermeasures which can reduce the radiation dose arising from the radioactive contamination of food products from animals. The choice of which countermeasure is suitable for each particular situation will depend on many factors. Consideration should be given not only to the effectiveness of each countermeasure in terms of reduction of radionuclide content, but also to its practicality and cost, particularly where deposition levels are high or where high contamination levels in animal food products persist for a long period of time. Effective countermeasures which can reduce radiocaesium contamination of milk and meat from farmed animals by more than a factor of 10 have been developed, tested and used during the last 30 years. Less progress has been made in identifying effective binders for reducing levels of the other important contaminating radionuclides, such as I and Sr, in animal food products.

Long-term consequences for Northern Norway of a hypothetical release from the Kola nuclear power plant.

The spatial and temporal variation in radiocaesium and (90)Sr doses to two population groups of the two Northernmost counties of Norway, Troms and Finnmark, following a hypothetical accident at the Kola nuclear power plant (KNPP) have been estimated using a model implemented within a geographical information system. The hypothetical accident assumes a severe loss of coolant accident at the KNPP coincident with meteorological conditions causing significant radionuclide deposition in the two counties. External doses are estimated from ground deposition and the behaviour of the different population groups, and internal doses from predicted food product activity concentrations and dietary consumption data. Doses are predicted for reindeer keepers and other Norwegian inhabitants, taking account of existing (137)Cs and (90)Sr deposition but not including the remedial effect of any countermeasures that might be used. The predicted doses, arising mainly from radiocaesium, confirm the Arctic Monitoring and Assessment Programme assessment that residents of the Arctic are particularly vulnerable to radiocaesium contamination, which could persist for many years. External doses are predicted to be negligible compared to ingestion doses. Ingestion doses for reindeer keepers are predicted to exceed 1 mSv y(-1) for several decades primarily due to their high consumption of reindeer meat. Other Norwegians would also be potentially exposed to doses exceeding 1 mSv y(-1) for several years, especially if they consume many local products. Whilst reindeer production is the most important exposure pathway, freshwater fish, lamb meat, dairy products, mushrooms and berries are also significant contributors to predicted ingestion doses. Radionuclide fluxes, defined as the total output of radioactivity in food from an area for a unit time, are dominated by reindeer meat. The results show the need for an effective emergency response, with appropriate countermeasures, should an accident of the scale considered in this paper occur at the KNPP.

Fluxes of radiocaesium in selected rural study sites in Russia and Ukraine.

Food production and food harvesting systems common in the areas contaminated by the Chernobyl accident in Russia and Ukraine can be grouped into three major categories: collective farm produce, private farming produce and foods collected from natural ecosystems. The contribution of each of these sources to radiocaesium intake by people living in rural settlements in the mid 1990s has been estimated at two major study sites, one in each country. The collective farm system provided the smallest contribution (7-14%) to the intake of radiocaesium at both sites. Natural food was the major contributor to intake at the Russian site (83%). Whereas private farm produce was the major contributor (68%) at the Ukrainian study site. The difference between the two sites was mainly because private milk production was stopped at the Russian site due to the contamination in 1986. A retrospective assessment of the situation 1 year after the accident shows that collective farming could have been a minor contributor to radiocaesium intake (8%), whilst private farming would have been the major contributor wherever private milk production and consumption continued. The extent to which inhabitants consume natural foods from forests has a considerable effect on their radiocaesium intake. The comparative importance of food products from natural ecosystems increases with time due to the long effective ecological half-lives of radiocaesium in unimproved pastures and forests. Estimation of the fluxes of radiocaesium from the different production and harvesting systems showed that the contribution from private farming and food harvesting from natural ecosystems may be significant, contributing 14-30% to the total fluxes of radiocaesium from an area even if the quantity of food produced in these systems is small. However, the major contributor to the flux exported from an area was the collective farming system, accounting for about 70-86% of the total.

The use of hexacyanoferrates in different forms to reduce radiocaesium contamination of animal products in Russia.

Hexacyanoferrates have been identified as highly effective radiocaesium binders which effectively reduce radiocaesium uptake and transfer to milk and meat. In Russia a hexacyanoferrate called ferrocyn has been produced for use as a countermeasure. In 1989-1992, experiments were undertaken in Russia to study the effectiveness of four different ferrocyn materials as 137Cs binders, their potential toxicity, effect on production rates of cow milk, effect on animal health and ease of implementation in routine agricultural practice. Four different ferrocyn delivery forms have been used: 98% pure powder, sustained release rumen boli (15% ferrocyn), salt licks (10% ferrocyn) and sawdust with 10% ferrocyn adsorbed (bifege). In initial experiments with different cows, sheep and pigs these four ferrocyn materials were effective in reducing radiocaesium transfer to animal products. Daily administration of ferrocyn powder at a rate of 3-5 g per cow reduced 137Cs transfer by up to 90% in milk. One single administration of three boli per cow (containing 30 g ferrocyn per boli) reduced 137Cs transfer by 50-75% for a period of 2 months. Salt licks containing 10% ferrocyn (0.22 kg ferrocyn per 2.2 kg briquette provided once) reduced transfer of 137Cs up to twofold for up to 10 days whilst bifege, given at a rate of 30-60 g day-1 (3-6 g day-1 ferrocyn), reduced 137Cs transfer by 90-95%. However, large-scale application of these ferrocyn materials on collective and private farms in agricultural trials in 1994 resulted in a lower effectiveness. Therefore, in 1996 a comparative assessment of the application of the four ferrocyn forms was made under carefully controlled conditions. The results fully validated the previous experimental data, and showed the importance of meeting recommended procedures for treatment, particularly when hexacyanoferrates are administered on a day-to-day basis.

The effects of prussian blue provided by indwelling rumen boli on the tissue retention of dietary radiocaesium by sheep.

A study was carried out to examine the effects of a form of Prussian Blue, provided by indwelling rumen boli, on the tissue retention of dietary radiocaesium by sheep. A single bolus providing 20-24 mg PB d-1 achieved a 42% reduction in tissue radiocaesium content. Multiple boli were not successful due to their loss from the rumen. The preparation used did not affect the health and well being of the animals.

Novel approaches to the estimation of intake and bioavailability of radiocaesium in ruminants grazing forested areas.

It is difficult to measure transfer of radiocaesium to the tissues of forest ruminants because they can potentially ingest a wide range of plant types. Measurements on undomesticated forest ruminants incur further difficulties. Existing techniques of estimating radiocaesium intake are imprecise when applied to forest systems. New approaches to measure this parameter are discussed. Two methods of intake estimation are described and evaluated. In the first method, radiocaesium intake is estimated from the radiocaesium activity concentrations of plants, combined with estimates of dry-matter (DM) intake and plant species composition of the diet, using plant and orally-dosed hydrocarbons (n-alkanes) as markers. The second approach estimates the total radiocaesium intake of an animal from the rate of excretion of radiocaesium in the faeces and an assumed value for the apparent absorption coefficient. Estimates of radiocaesium intake, using these approaches, in lactating goats and adult sheep were used to calculate transfer coefficients for milk and muscle; these compared favourably with transfer coefficients previously obtained under controlled experimental conditions. Potential variations in bioavailability of dietary radiocaesium sources to forest ruminants have rarely been considered. Approaches that can be used to describe bioavailability, including the true absorption coefficient and in vitro extractability, are outlined.

Plasma urea, creatinine, and urea: creatinine ratio in reindeer (Rangifer tarandus tarandus) and in Svalbard reindeer (Rangifer tarandus platyrhynchus) during defined feeding conditions and in the field.

Variation in plasma urea and creatinine concentration and plasma urea:creatinine ratio (U:C) were studied in semidomestic free-ranging reindeer (Rangifer tarandus tarandus) on the Norwegian mainland, in wild Svalbard reindeer (Rangifer tarandus platyrhynchus), and in captive reindeer maintained either on a lichen-based diet or a protein-rich concentrate to investigate whether these parameters could be used as indicators of the nutritional status of reindeer. In the mainland animals, plasma creatinine concentration was high in winter and early spring and decreased by two-thirds toward the summer. The overall range in mean plasma creatinine concentration (+/-SE) was from 90+/-1.26 to 280+/-2.88 micromol/L. Mean plasma urea concentration (+/-SE) varied from 2.46+/-0.10 in winter up to 17.44+/-0.29 mmol/L in summer and autumn. Month of sampling explained 65% and 90% of the variation in plasma urea and creatinine concentrations, respectively, indicating that seasonality in the diet had the greatest influence on these parameters. Reindeer given lichens as the only feed showed an increase in plasma creatinine and a decrease in plasma urea concentration. Food restriction caused a temporary elevation in urea level but had no significant effect on plasma creatinine concentration. The slight effect of energy intake on urea and creatinine levels was supported by the fact that severe undernutrition in the Svalbard reindeer population had only a small effect on plasma urea and creatinine levels. Protein-rich pellet feed increased plasma urea from around 3 mmol/L to above 10 mmol/L and reduced creatinine concentrations to less than 100 micromol/L, suggesting that the protein content of forage is an important determinant of these blood parameters. Mean U:C ratio (+/-SE) in plasma varied from 8.9+/-0.28 to 120.8+/-1.88. Ratios above 20 appeared when protein intake was low and energy intake was restricted or when protein intake was high. Low ratios occurred when protein intake was low but energy intake adequate. Plasma urea and creatinine concentrations and the U:C ratio showed complex dynamics that were affected by both season and the protein and feed intake. We conclude that they appear to be difficult to interpret as single measures of nutritional status of reindeer.

Radiocesium bioavailability: transfer of Chernobyl and tracer radiocesium to goat milk.

The bioavailability of Chernobyl-derived radiocesium in hay, fungal fruit bodies, willow bark, and soil was compared to tracer radiocesium (134CsCl) by measuring transfer coefficients (Fm) to goat milk. The average Fm value from 134CsCl of 11.9 x 10(-2) d L-1 was taken to represent the maximal transfer to milk on the provided diet. In 1986, the Fm value from hay was 35% of that from 134CsCl, thus demonstrating the low bioavailability of recently deposited radiocesium. Values in 1987 were also lower, with a mean of 76% of that from tracer Cs. During 1988 and 1989, maximal Fm values were observed, suggesting increased bioavailability from the year of fallout to the following years. Transfer of radiocesium from two fungal species harvested in 1988 and 1989 were 78% and 87%, respectively, of that from tracer Cs, while bark was lower (62%). Transfer from organic soil was only 7% of tracer radiocesium, and therefore contribution from soil ingestion could only have a small impact on the content of radiocesium in animals. Live monitoring measurements and the excretion of 134Cs in milk, urine, and feces during a 50-d period was adequately described by a two-exponential equation.

Transfer of radiocesium to ruminants in natural and semi-natural ecosystems and appropriate countermeasures.

A review of studies conducted before and after the Chernobyl accident is presented, showing that both the duration and the extent of radiocesium contamination of ruminants will be more severe in unimproved ecosystems compared with agricultural areas. Although such unimproved ecosystems provide comparatively small quantities of food for human consumption, the integrated dose from these areas to the human population can be large. Ecological characteristics that make unimproved ecosystems particularly vulnerable to this form of pollution include the presence of (1) soils that do not immobilize radiocesium and therefore allow its uptake into vegetation; (2) vegetation species with high uptake rates of radiocesium; (3) the predominant utilization by small ruminants which attain higher muscle radiocesium levels than cattle. Unimproved ecosystems, which often are located at high altitudes, are predisposed to receiving higher fallout because of high precipitation rates which enhance the likelihood of deposition. Countermeasures have been developed and used successfully to reduce radiocesium levels in ruminants grazing in unimproved ecosystems. Apart from decontamination by altering farming practices and providing uncontaminated feeds, sustained reductions of 50% to 80% in the radiocesium concentrations of both milk and meat have been achieved in many ruminant species when AFCF is given via a sodium chloride lick or as a sustained-release bolus. Food production in unimproved ecosystems must be evaluated separately from that of ordinary agricultural systems. In addition to detailed studies on the behavior of radiocesium, consideration should be given to the collection of aggregated transfer coefficients from various ecosystems which were affected by Chernobyl fallout. By combining bioavailability estimates and aggregated transfer coefficients, based on Chernobyl and nuclear weapons test fallout data, it may in the future be possible to make a rapid assessment of both the immediate and the long-term impact of a future nuclear accident on food production in unimproved ecosystems.