Simulated eutrophication and browning alters zooplankton nutritional quality and determines juvenile fish growth and survival

The first few months of life is the most vulnerable period for fish and their optimal hatching time with zooplankton prey is favored by natural selection. Traditionally, however, prey abundance (i.e., zooplankton density) has been considered important, whereas prey nutritional composition has been largely neglected in natural settings. High‐quality zooplankton, rich in both essential amino acids (EAAs) and fatty acids (FAs), are required as starting prey to initiate development and fast juvenile growth. Prey quality is dependent on environmental conditions, and, for example, eutrophication and browning are two major factors defining primary producer community structures that will directly determine the nutritional quality of the basal food sources (algae, bacteria, terrestrial matter) for zooplankton. We experimentally tested how eutrophication and browning affect the growth and survival of juvenile rainbow trout (Oncorhynchus mykiss) by changing the quality of basal resources. We fed the fish on herbivorous zooplankton (Daphnia) grown with foods of different nutritional quality (algae, bacteria, terrestrial matter), and used GC‐MS, stable isotope labeling as well as bulk and compound‐specific stable isotope analyses for detecting the effects of different diets on the nutritional status of fish. The content of EAAs and omega‐3 (ω‐3) polyunsaturated FAs (PUFAs) in basal foods and zooplankton decreased in both eutrophication and browning treatments. The decrease in ω‐3 PUFA and especially docosahexaenoic acid (DHA) was reflected to fish juveniles, but they were able to compensate for low availability of EAAs in their food. Therefore, the reduced growth and survival of the juvenile fish was linked to the low availability of DHA. Fish showed very low ability to convert alpha‐linolenic acid (ALA) to DHA. We conclude that eutrophication and browning decrease the availability of the originally phytoplankton‐derived DHA for zooplankton and juvenile fish, suggesting bottom‐up regulation of food web quality.     

Glucosinolates in <Emphasis Type="Italic">Brassica</Emphasis> foods: bioavailability in food and significance for human health

Glucosinolates are sulphur compounds that are prevalent in Brassica genus. This includes crops cultivated as vegetables, spices and sources of oil. Since 1970s glucosinolates and their breakdown products, have been widely studied by their beneficial and prejudicial biological effects on human and animal nutrition. They have also been found to be partly responsible for the characteristic flavor of Brassica vegetables. In recent years, considerable attention has been paid to cancer prevention by means of natural products. The cancer-protective properties of Brassica intake are mediated through glucosinolates. Isothyocianate and indole products formed from glucosinolates may regulate cancer cell development by regulating target enzymes, controlling apoptosis and blocking the cell cycle. Nevertheless, variation in content of both glucosinolates and their bioactive hydrolysis products depends on both genetics and the environment, including crop management practices, harvest and storage, processing and meal preparation. Here, we review the significance of glucosinolates as source of bioactive isothiocyanates for human nutrition and health and the influence of environmental conditions and processing mechanisms on the content of glucosinolate concentration in Brassica vegetables. Currently, this area is only partially understood. Further research is needed to understand the mechanisms by which the environment and processing affect glucosinolates content of Brassica vegetables. This will allow us to know the genetic control of these variables, what will result in the development of high quality Brassica products with a health-promoting activity.     

Biosurfactant-producing yeasts widely inhabit various vegetables and fruits

The isolation of biosurfactant-producing yeasts from food materials was accomplished. By a combination of a new drop collapse method and thin-layer chromatography, 48 strains were selected as glycolipid biosurfactant producers from 347 strains, which were randomly isolated from various vegetables and fruits. Of the producers, 69% were obtained from vegetables of the Brassica family. Of the 48 producers, 15 strains gave relatively high yields of mannosylerythritol lipids (MELs), and were identified as Pseudozyma yeasts. These strains produced MELs from olive oil at yields ranging from 8.5 to 24.3?g/L. The best yield coefficient reached 0.49?g/g as to the carbon sources added. Accordingly, MEL producers were isolated at high efficiency from various vegetables and fruits, indicating that biosurfactant producers are widely present in foods. The present results should facilitate their application in the food and related industries.     

Fresh fruit and vegetables as vehicles for the transmission of human pathogens

Much research into food‐borne human pathogens has focused on transmission from foods of animal origin. However, recent investigations have identified fruits and vegetables are the source of many disease outbreaks. Now believed to be a much larger contributor to produce‐associated outbreaks than previously reported, norovirus outbreaks are commonly caused by contamination of foods from hands of infected workers. Although infections with Shiga toxin‐producing E. coli O157 have been linked to beef more often than to any other food product, severe outbreaks have been traced to consumption of contaminated radish sprouts and pre‐packaged spinach. Similarly, while infections with Salmonella have mainly been linked to consumption of foods of animal origin, many outbreaks have been traced to contaminated fresh produce. E. coli O157 binds to lettuce leaves by alternative mechanisms involving the filamentous type III secretions system, flagella and the pilus curli. Association of Salmonella with fresh produce appears to be serovar‐specific involving flagella, curli, cellulose, and O antigen capsule. A better understanding of plant, microbiological, environmental, processing and food handling factors that facilitate contamination will allow development of evidence‐based policies, procedures and technologies aimed at reducing the risk of contamination of fresh produce.     

Prey nutritional quality and the effectiveness of chemical defenses against tropical reef fishes

Summary Many coral-reef seaweeds and sessile invertebrates produce both secondary chemicals and mineral or fibrous skeletal materials that can reduce their susceptibility to consumers. Although skeletal materials often have been assumed to function as physical defenses, their deterrent effectiveness may derive from their reduction of prey nutritional quality as well as from noxiousness of the skeletal material itself. To test the relative importance of prey nutritional quality and chemical defenses in susceptibility to predation, we offered reef fishes on Guam a choice of artificial foods varying in nutritional quality (4% versus 22% protein) and in secondary chemistry (spanning approximately natural concentration ranges). Field feeding assays were performed with pachydictyol A from the pantropical brown seaweed genus Dictyota, manoalide from the Micronesian sponge Luffariella variabilis, and a brominated diphenyl ether from the Micronesian sponge Dysidea sp. The results indicated that chemical defenses were less effective in high- than in low-quality foods. In paired assays with metabolite-free controls, all three compounds at natural concentrations significantly reduced feeding by reef fishes only in assays using low-quality food, and not in assays with high-quality food. When fishes were offered an array of artificial foods varying in both food quality and metabolite concentration, food quality significantly affected fish feeding in all three cases, while secondary chemistry was significant in only one. Thus differences in nutritional quality, within the natural range among reef organisms, can be comparable to or greater in importance than secondary chemistry in affecting feeding preferences of their consumers. Reduced nutritional quality may be an important selective advantage of producing indigestible structural materials, in addition to their roles as physical support and defense, in coral reef organisms.     

The importance of honeydew as food for larvae of Chrysoperla carnea in the presence of aphids

Larvae of the common green lacewing Chrysoperla carnea are predacious and feed on a wide range of small, soft‐bodied arthropods. In addition to their feeding on prey arthropods to cover their nutritional requirements for growth and development, the consumption of non‐prey foods such as honeydew has been reported. It is commonly believed that these food supplements are primarily exploited by the larvae when prey is scarce or of low nutritional quality. Here, we assess whether C. carnea larvae also use honeydew when high‐quality aphid prey are readily available. In a choice experiment, the feeding behaviour of C. carnea larvae was observed in the presence of both aphids and honeydew. The larvae were starved, aphid‐fed, or honeydew‐fed prior to the experiment. The time spent feeding on honeydew compared with feeding on aphids was highest for starved larvae and lowest for honeydew‐fed larvae. Among the three treatments, the aphid‐fed larvae spent the most time resting and the least time searching. In an additional experiment food intake was assessed in terms of weight change when larvae were provided with an ad libitum supply of either aphids or honeydew. Larvae yielded a significant lower relative weight increase on honeydew compared with aphids. The reduced weight increase on honeydew was compensated when larvae were subsequently provided with aphids, but not when honeydew was provided again. This study showed that (i) prior honeydew feeding reduces overall aphid consumption, and (ii) larvae do consume honeydew even after they have been given ad libitum access to aphids. The fact that larvae of C. carnea still use honeydew as a food source in the presence of suitable prey underlines the importance of carbohydrates as foods.     

Nutritional correlates of the “lean season”: Effects of seasonality and frugivory on the nutritional ecology of diademed sifakas

Primate field studies often identify “lean seasons,” when preferred foods are scarce, and lower‐quality, abundant foods (fallback foods) are consumed. Here, we quantify the nutritional implications of these terms for two diademed sifaka groups (Propithecus diadema) in Madagascar, using detailed feeding observations and chemical analyses of foods. In particular, we sought to understand 1) how macronutrient and energy intakes vary seasonally, including whether these intakes respond in similar or divergent ways; 2) how the amount of food ingested varies seasonally (including whether changes in amount eaten may compensate for altered food quality); and 3) correlations between these variables and the degree of frugivory. In the lean season, sifakas shifted to non‐fruit foods (leaves and flowers), which tended to be high in protein while low in other macronutrients and energy, but the average composition of the most used foods in each season was similar. They also showed dramatic decreases in feeding time, food ingested, and consequently, daily intake of macronutrients and energy. The degree of frugivory in the daily diet was a strong positive predictor of feeding time, amount ingested and all macronutrient and energy intakes, though season had an independent effect. These results suggest that factors restricting how much food can be eaten (e.g., handling time, availability, or intrinsic characteristics like fiber and plant secondary metabolites) can be more important than the nutritional composition of foods themselves in determining nutritional outcomes—a finding with relevance for understanding seasonal changes in behavior, life history strategies, competitive regimes, and conservation planning. Am J Phys Anthropol 153:78–91, 2014. © 2013 Wiley Periodicals, Inc.     

Ultimate and proximate mechanisms underlying the occurrence of bears close to human settlements: review and management implications

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A comparison of the nutritional status and food security of drug-using and non-drug-using Hispanic women in Hartford,Connecticut

This study compared food insecurity, nutritional status (as measured through anthropometry and dietary intake), and food preparation patterns of low-income Puerto Rican female out-of-treatment drug users with that of low-income Puerto Rican women who reported no drug use. A convenience sample of 41 drug users was compared with 41 age-matched non-drug-users from inner-city Hartford, Connecticut. A culturally appropriate food frequency questionnaire was administered and anthropometric measurements were taken. The findings suggest a high degree of poverty among all study participants, but in particular among drug users. Drug users were more likely than the controls to be food insecure (P < 0.05) and to be exposed to increasingly severe food sufficiency problems. The daily frequency of consumption of vegetables was lower (P = 0.03) for drug users than non-drug-users. Conversely, the frequency of consumption for sweets/ desserts was significantly higher for drug users than the controls (P = 0.0001). Drug users, who were classified as food insecure were less likely to consume vegetables (P = 0.004) and fish (P = 0.03) than were controls who were food insecure. When comparing drug users with controls, the former group reported consuming fewer meals during a usual week than the latter group (P < 0.0001). Drug users were more likely to fry foods (P = 0.02) while the controls were more likely to bake (P = 0.005), boil (P = 0.02), and steam (P = 0.002) foods. All anthropometric measurements, except for height, were significantly lower for drug users. The results show that drug users generally maintain poorer nutritional status than non-drug-users. Nutrition interventions as part of drug treatment are needed. Am J Phys Anthropol 107:351–361, 1998. © 1998 Wiley-Liss, Inc.     

Diurnal Variation in Nutrients and Chimpanzee Foraging Behavior

Primate feeding behavior varies over long (e.g., weekly, seasonally, yearly) and short (e.g., hourly) scales of time due to changes in resource availability and the nutritional composition of foods. While the factors that affect long‐term changes in feeding behavior have received considerable attention, few data exist regarding what drives variability in feeding behavior over the course of a single day. To address this problem, we investigated diurnal variation in chimpanzee feeding on the leaves of two species of saplings, Pterygota mildbraedii and Celtis africana, at Ngogo, Kibale National Park, Uganda. Specifically, we related short‐term changes in chimpanzee feeding behavior on these leaves to diurnal variation in their nutritional composition. Results showed that chimpanzees fed on the leaves of both saplings more in the evening than they did in the morning. The nutritional quality of leaves also improved over the course of the day. Concentrations of cellulose and lignin were lower and total nonstructural carbohydrates (including sugars and starch) were higher in the evening for P. mildbraedii, and sugars were higher in the evening for C. africana. These data suggest that chimpanzees consume these resources when their quality is highest, and consequently, may track the nutrient composition of their foods over very short periods that span only a few hours. In the future, foods collected for analyses must control for time of sampling to ensure biologically meaningful assays of nutrient composition. Am. J. Primatol. 75:342‐349, 2013. © 2013 Wiley Periodicals, Inc.     

Nutrient contents predict the bamboo‐leaf‐based diet of Assamese macaques living in limestone forests of southwest Guangxi,China

Determining the nutrient factors influencing food choice provides important insight into the feeding strategy of animals, which is crucial for understanding their behavioral response to environmental changes. A bamboo‐leaf‐based diet is rare among mammals. Animals’ food choice and nutritional goals have been explained by several frameworks; however, the influence of nutrients on food choice in bamboo‐leaf‐based macaques is not yet available. Assamese macaques (Macaca assamensis) inhabiting limestone forests are characterized by such a bamboo‐leaf‐based diet, predominantly consuming young leaves of Bonia saxatilis, a shrubby, karst‐endemic bamboo. We studied the feeding behavior of one group of Assamese macaques using instantaneous scan sampling in limestone forests of the Guangxi Nonggang National Nature Reserve in southwest Guangxi, China. We compared the nutrient content of staple food and nonfood items and examine the role of key nutrients in the food selection of macaques. Our results showed that young leaves of bamboo B. saxatilis contained more water, crude protein, phosphorus, and less tannin than nonfood items. Furthermore, staple foods contained a higher content of water and less content of calcium than nonfood items. More specifically, quantities of water, crude protein, calcium, and phosphorus in food items were critical factors affecting feeding time on a specific plant item. Our results suggest that young bamboo leaves could meet macaques’ required protein and water intake, while enabling them to maintain their mineral balance, consequently facilitating to maintain the primates’ bamboo‐leaf‐diet in the limestone forest. Our findings confirm the effects of nutrient contents in food choice of Assamese macaques, highlighting the importance of the nutrient contents in maintaining their bamboo‐based diet and the need to increase the knowledge on their nutritional strategy adapted to the bamboo‐dominated diet inhabiting the unique limestone habitat.     

Steller sea lions Eumetopias jubatus and nutritional stress: evidence from captive studies

• 1 Numbers of Steller sea lions Eumetopias jubatus in the North Pacific have declined. According to the nutritional stress hypothesis, this decline is due to reduced food availability. Data from studies conducted on pinnipeds in the laboratory are used here to test if the nutritional stress hypothesis can explain the decline of Steller sea lions.
• 2 Overall, there is strong evidence for biologically meaningful differences in the nutritional quality of major prey species. Steller sea lions can partly compensate for low‐quality prey by increasing their food consumption.
• 3 There appear to be no detrimental effects of low‐lipid prey on sea lion growth or body composition when sea lions can consume sufficient quantities of prey. However, the ability to increase consumption is physiologically limited, particularly in young animals. Overall, it is more difficult to maintain energy intake on a diet of low‐quality prey than on a normal diet.
• 4 Under conditions of inadequate food intake (either due to decreased prey availability or quality, or increased energy requirements) the overall impacts of nutritional stress are complex, and are dependent upon season, prey quality, age and the duration and intensity of the nutritional stress event.
• 5 Studies on pinnipeds in the laboratory have been instrumental in identifying the conditions under which changes in sea lion prey can result in nutritional stress and the nature of the physiological impacts of nutritional stress events.

     

Ethnic differences in lifestyle and overweight in the Netherlands

Objective: To study the effects of lifestyle variables and socioeconomic status on overweight among native Dutch and immigrants in The Netherlands. Research Methods and Procedures: Data were used from a survey sample (N = 2551) of native Dutch and immigrant respondents (Surinamese/Antilleans, Turks, and Moroccans). BMI was calculated using self‐reported weight and height. Lifestyle variables such as modern food habits (take‐out food and eating out) and participating in sports were included, as well as socioeconomic and demographic background variables. Bivariate and ordinary least squares analyses were performed to study BMI and the determinants of overweight among the different groups. Results: All immigrant groups had a higher prevalence of overweight than the Dutch, except Moroccans. Men were overweight more frequently than women. Take‐out food, eating out, and fresh vegetables were related to a decrease in BMI, whereas convenience foods were related to an increase in BMI. For ready‐to‐eat meals, the results were mixed. In all groups, age was associated with a higher BMI, and a higher level of education was associated with a lower BMI. Immigrants participated in sports less frequently than native Dutch people. Discussion: One percent to 5% of the total public health costs can be attributed to costs for overweight‐related diseases. Public health policies should aim at stimulating healthy lifestyles and discouraging bad food habits through higher taxes on high‐calorie foods. In particular, Dutch immigrants should be encouraged to lose weight, because they have a higher risk for overweight‐related diseases.     

Bioactive Sulforaphane from in vitro Propagated Brassica Seedlings

Sulforaphane is a biologically active phytochemical found abundantly in Brassica species. Sulforaphane from eighteen samples of three‐day‐old in vitro seedlings from Brassicas, the Brassica oleracea and Brassica rapa varieties were analyzed by HPLC. San Martino, cavolfiore Alverda, cavolo verza riccio d'Asti and cavolfiore Minaret (4.57; 4.54; 4.53 and 4.53 [mg/g d.w], respectively) seedlings showed the highest level of sulforaphane. The presented data may be applicable to choose sulforaphane‐rich Brassica varieties for functional foods. A higher sulforaphane content in functional foods might offer health benefits or desirable physiological effects.     

Bryophyte use by an insect herbivore: does the crane‐fly Tipula montana select food to maximise growth?

1. Growth rates of immature invertebrates can be of profound importance to subsequent reproductive success in the adult stage. If diet selection in herbivores is a principal means of maximising growth and rate of development, individuals should select food of the highest quality. 2. If disparities are found between performance and preference, these may be the result of individuals balancing nutritional gain against other demands on their behaviour, such as a need for shelter. The responses of the crane‐fly herbivore Tipula montana Curtis (Diptera: Tipulidae) to a range of moss genera from an upland environment were investigated to determine whether diet selection was determined by food quality alone, as measured by its effect on larval growth and survival. 3. Larvae were reared individually on single moss genus diets, and their growth, development, and survival were measured. Each of the mosses supported growth and development although the mean weights achieved differed by a factor of two between food genera. In two‐choice preference experiments, individuals broadly chose bryophyte foods as expected from their quality. One notable exception was the moss Pleurozium schreberi, which gave the best growth performance but was among the least preferred. 4. The two methods of assessing preference gave different results: observations of larvae showed relatively greater selection for dense mosses than faecal pellet analysis. A strong dietary preference for an angiosperm, the sedge Carex bigelowii, over all mosses supported the interpretation that crane‐fly larvae benefit from bryophytes as a refuge, and that this factor may override dietary quality.     

The importance of high‐quality algal food sources in stream food webs – current status and future perspectives

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Increasing healthy eating vs. reducing high energy-dense foods to treat pediatric obesity

Objective: The objective was to compare targeting increased eating of healthy foods vs. reducing intake of high energy‐dense foods within the context of a family‐based behavioral weight control program. Methods and Procedures: Forty‐one 8–12 year‐old children >85th BMI percentile were randomly assigned to a 24‐month family‐based behavioral treatment that targeted increasing fruits and vegetables and low‐fat dairy vs. reducing intake of high energy‐dense foods. Results: Children in the increase healthy food group showed greater reduction in zBMI compared to children in the reduce high energy‐dense food group at 12‐ (?0.30 zBMI units vs. ?0.15 zBMI units, P = 0.01) and 24‐ (?0.36 zBMI units vs ?0.13 zBMI units, P = 0.04) month follow‐up. Parents in the increase healthy food group showed greater reductions in concern about child weight (P = 0.007), and these changes were associated with child zBMI change (P = 0.008). Children in the reduce high energy‐dense group showed larger sustained reductions in high energy‐dense foods (P < 0.05). Baseline levels of high energy‐dense foods (P < 0.05), parent food restraint (P = 0.01), parent concern over parent weight (P = 0.01) and parent acceptance of the child (P < 0.05) moderated child zBMI change, with greater sustained reductions in zBMI for children in the increase healthy food group for each measure. Parent zBMI change followed the same pattern as child changes, and parent and child zBMI changes were correlated (P < 0.001). Discussion: Focusing on healthy food choices within an energy restricted diet may be useful in family‐based weight control programs.     

Food selection by calanoid copepods in response to between-lake variation in food abundance

1. Food selection experiments were conducted by acclimating calanoid copepods (Eudiaptomus spp.) in suspensions of natural seston and then adding pairs of dual-labelled (¹⁴C/³²P) algae. Each feeding trial measured selectivity between a small, high-quality reference alga, Chlamydomonas reinhardii, and a test alga that differed in size and/or food quality. The influence of food concentration on food selection was tested by using seston from two lakes with contrasting food abundance and by including treatments with filtered lake water ('starved’) and seston diluted with filtered water or enriched with cultured algae. 2. Copepods that had been starved or acclimated to natural seston with low food abundance preferred the larger of two labelled algae, regardless of the nutritional quality of the algae. In agreement with the predictions of an optimal diet model, however, copepods that were acclimated to high food conditions discriminated against low-quality foods, including digestion-resistant algae and dead algae. 3. Selectivity coefficients showed excellent agreement with a previous study involving the same taxa of copepods and labelled algae but in which the copepods had been acclimated to pairs of cultured algae rather than natural seston. Thus, these comparisons emphasize the importance of food availability in modulating copepod selectivity for foods that differ in nutritional quality and suggest that such behaviour occurs in nature.