Two healthy men were evaluated before and after a 56 day raft voyage to determine endocrine and metabolic status immediately after and during the recovery phase after long term caloric, protein, and water deprivation. Daily intake during the trip consisted of no protein, 300 ml water, and for the first 40 days, 300 Kcal glucose. The subjects lost weight from 84.1 to 58.1 and 78.3 to 57.7 kg, respectively. Other variations were measured including rate of excretion, diurnal patterns, serum testosterone levels, plasma insulin levels, serum glucose concentrations, triglyceride content, liver function, fat and xylsoe absorption, and renal function.

Diet and drinking water are suggested to be major exposure pathways for perfluoroalkyl substances (PFASs). In this study, food items and water from Faroe Islands sampled in 2011/2012 were analyzed for 11 perfluoroalkyl carboxylic acids (PFCAs) and 4 perfluoroalkane sulfonic acids (PFSAs). The food samples included milk, yoghurt, crème fraiche, potatoes, fish, and fish feed, and the water samples included surface water and purified drinking water. In total, nine PFCAs and four PFSAs were detected. Generally, the levels of PFAS were in the lower picogram per gram range. Perfluorobutanoic acid was a major contributor to the total PFASs concentration in water samples and had a mean concentration of 750 pg/L. Perfluoroundecanoic acid (PFUnDA) was predominating in milk and wild fish with mean concentrations of 170 pg/g. Perfluorooctane sulfonic acid (PFOS) was most frequently detected in food items followed by PFUnDA, perfluorononanoic acid, and perfluorooctanoic acid (PFOA). Levels of PFUnDA and PFOA exceeded those of PFOS in milk and fish samples. Prevalence of long-chain PFCAs in Faroese food items and water is confirming earlier observations of their increase in Arctic biota. Predominance of short-chain and long-chain homologues indicates exposure from PFOS and PFOA replacement compounds.

Ecuador is facing several threats to its food and water security, with over a tenth of its population currently undernourished and living in poverty. As a response, its government is incorporating new patterns of land use and developing regional water infrastructure to cope with the related challenges. In this study, we assess to what point these efforts contribute to integrated water and food security in the country. We investigated the period 2004–2013 in the most productive agricultural region - the Guayas river basin district (GRBD) - and analysed the impacts of different scenarios of agricultural change on local water security. Our approach integrates MuSIASEM (Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism) with the hydrological SWAT model. Freshwater allocation is evaluated within all the water cycle from its source (natural systems) to the final users (societal systems). Water security is assessed spatiotemporally in terms of water stress for the population living in poverty. Water productivity is obtained in relation to agricultural production and nutrition. The multi-scale analysis shows that whereas at river basin district level the median annual streamflow has a similar magnitude than rainfall stored in soil, these two parameters differ spatiotemporally at subbasin level. The study finds the greatest challenge in achieving water security is the south-east and central part of the GRBD, due to water scarcity and a larger population living in poverty. However, these areas are also simultaneously, where the greatest crop water productivity is found. We conclude that food production for both domestic consumption and market-oriented exports can be increased while meeting ecosystem water demands in all the GRBD regions except for the east. Our integration of methods provides a better approach to inform integrated land and water management and is relevant for academics, practitioners and policymakers alike.

Natalie G. Schimpf, Philip G. D. Matthews, and Craig R. White

Time—energy budgets (TEB) of Gambel's Quail (Callipepla gambelii) were compiled during two summers in the Colorado Desert of California. Quail spent 6.77 h/d foraging, 6.2 h/d inactive during daylight hours, and 11.02 h/d inactive at night. Field metabolic rate (FMR) calculated from this activity budget was 81.8 kJ/d. Of this, 47.3 kJ/d was expended during foraging, 12.6 kJ/d in daytime inactivity, and 20.4 kJ/d in nighttime inactivity. Despite the extremely hot thermal environment (maximum ambient temperature °45°C), there was no energy cost above resting levels for thermoregulation. FMR was also measured simultaneously with doubly labeled water (DLW), and averaged 90.8 kJ/d. TEB and DLW values agreed to within 6% when differences in measurement period were taken into account. A laboratory validation study indicated that DLW and balance methods agreed to within 5%. The FMR of C. gambelii was only 40% of that predicted for a bird of its body mass. This low FMR is primarily the result of a low resting metabolic rate (RMR): 51% of the predicted basal rate in 1981, and 70% of predicted in 1982. The basis and significance of this low and variable RMR are unclear. Energy assimilation efficiency, measured in laboratory feeding experiments with a mixed seed and arthropod diet, was 60.3%. An individual quail in the field thus required 150.3 kJ/d in its diet, representing a dry matter intake of 8.1 g/d. A diet of seeds alone provides insufficient water for Gambel's Quail in summer, so they must either incorporate moist food items in their diet or drink free water. It was calculated that over the course of a year, a population of Gambel's Quail consumes seeds with a total energy content °15% as great as that in seeds consumed by a population of desert rodents or harvester ants in the same area. Gambel's Quail thus may be important factors in the competition for resources among desert granivores, particularly because they can eat one of their competitors (harvester ants).

In order to provide information on the state of hydration of broilers during marketing, 7-week-old Ross broilers of mixed sex were kept at 17 or 23 degrees C and deprived of food, or food and water, for 24 h. Measurements were made of live weight, carcass weight, muscle moisture, packed cell volume, plasma glucose, corticosterone, total protein, osmolality and sodium. There was a decrease in live weight, carcass weight, plasma glucose and plasma total protein, and an increase in packed cell volume and corticosterone, in birds deprived of food, or food and water. Muscle moisture increased in birds deprived of food and decreased in birds deprived of food and water. Osmolality decreased in birds deprived of food, the decrease being greater in birds at 23 degrees C. Plasma sodium levels were higher in birds kept at 23 degrees C and increased only in birds deprived of food and water at 23 degrees C.

Information on the macronutrient composition of the diet is needed in doubly labeled water studies to convert measured rates of carbon dioxide production into values for total energy expenditure. There is no general consensus, however, about the best method to determine food intake for this purpose. Four common methods of measuring food intake (7-day weighed food intake, 24-hour recall, and Fred Hutchinson Cancer Research Center/Block and Willett food frequency questionnaires) were tested for their ability to provide comparable food quotient and total energy expenditure data in doubly labeled water studies in 10 young and 10 older women. All methods gave mean values for total energy expenditure that were within 1% of each other. Individual values obtained using the 24-hour recall and food frequency questionnaires were within +/-3% (standard deviation) of values determined using data from the 7-day weighed food record. These results suggest that it is not necessary to use time-consuming and expensive 7-day food records in doubly labeled water studies; instead, food intake data obtained more easily by 24-hour recall or food frequency questionnaire can provide comparable data.

Nitric oxide has been suggested to be involved in the regulation of fluid and nutrient homeostasis. In the present investigation, vasopressin and nitric oxide metabolite (nitrite and nitrate) levels were determined in plasma of male Wistar rats submitted to water or food deprivation for three days. Hematocrit and plasma sodium showed marked increase in dehydrated and starved rats. Potassium levels and plasma volume decreased in both treated groups. Plasma osmolality and vasopressin levels were significantly elevated in water deprived (362.8±7.1 mOsm/kg H₂O, 17.3±2.7 pg/ml, respectively, p<0.001) rats, but not in food deprived (339.9±5.0, 1.34±0.28) rats, compared to the controls (326.1±4.1, 1.47±0.32). The alterations observed in plasma vasopressin levels were related to plasma osmolality rather than plasma volume. Plasma levels of nitrite and nitrate were markedly increased in both water and food deprived rats (respectively, 2.19±0.29 mg/l and 2.22±0.17 mg/l <i>versus</i>1.33±0.19 mg/l, both p<0.01). There was a significant negative correlation between plasma nitrite and nitrate concentration and plasma volume. These results suggest that both dehydration and starvation increase plasma nitric oxide, probably by activation of nitric oxide synthases. The release of nitric oxide may participate in the regulation of the alteration in blood flow, fluid and nutrient metabolism caused by water deprivation or starvation.

Salmonella can survive for extended periods of time in low-moisture environments posing a challenge for modern food production. This dangerous pathogen must be controlled throughout the production chain with a minimal risk of dissemination. Limited information is currently available describing the behavior and characteristics of this important zoonotic foodborne bacterium in low-moisture food production environments and in food. In our study, the phenotypes related to low-moisture survival of 46 Salmonella isolates were examined. Most of the isolates in the collection could form biofilms under defined laboratory conditions, with 57% being positive for curli fimbriae production and 75% of the collection positive for cellulose production, which are both linked with stronger biofilm formation. Biocides in the factory environment to manage hygiene were found to be most effective against planktonic cells but less so when the same bacteria were surface dried or present as a biofilm. Cellulose-producing isolates were better survivors when exposed to a biocide compared with cellulose-negative isolates. Examination of Salmonella growth of these 18 serotypes in NaCl, KCl, and glycerol found that glycerol was the least inhibitory of these three humectants. We identified a significant correlation between the ability to survive in glycerol and the ability to survive in KCl and biofilm formation, which may be important for food safety and the protection of public health.

The objective of the study reported here was to investigate three factors that may affect the amounts of water consumed and urine excreted by a rat in the metabolism cage: water dilution, housing, and food. Young F344/N rats (eight per group) were used for all experiments. Food was withheld from rats before each 16-h urine collection, then rats were transferred into a metabolism cage. For trial A (water dilution), urine was collected from rats supplied with dyed water (0.05%,vol/vol). This was repeated three times over a 2-week period. Dye in water or urine was quantified, using a spectrophotometer. For trial B (housing), rats were individually housed in wire cages for 3 weeks before the first urine collection. Then they were group housed in the solid-bottom cage (four per cage). After 2 weeks of acclimation, urine collection was repeated. For trial C (food), one group of rats was provided with food, the other was not, during urine collection. About 8% of urine samples of small volume (less than or equal to 3 ml) from trial A were contaminated with drinking water up to 13% of volume. The average urine volume associated with individual housing was approximately twice as large as that associated with group housing. When food was provided during urine collection, rats consumed similar amounts of water but excreted significantly smaller amounts of urine than did rats without food. It was concluded that water dilution of a urine sample from a sipper bottle is relatively small; rats individually housed in wire caging before urine collection can consumed and excrete a larger quantity of water, compared with rats group housed in solid-bottom cages: and highly variable urine volumes are, in part, associated with lack of access to food during urine collection.