Length–weight relationship and condition factor of the Characidae matrinxã, Brycon falcatus (Müller & Troschel, 1844), in the Teles Pires River,southern Amazon

The aim of this study was to verify whether the in situ supply of soybean as a fish attractant bears any influence on the length–weight relationship and condition factor of the omnivorous fish species, Brycon falcatus. In addition, estimated was the length–weight relationship, standard and total length, condition factor, and size of B. falcatus in the spawning period in the Teles Pires River Basin. In the experimental design, rivers of the Teles Pires Basin containing soybean attractant (Verde River, Celeste River, Teles Pires River and the Tapaiuna River) were mapped. Fish were also collected from the Cristalino River, which contained no soybean attractant (treatment control). Samples were collected from August 2012 to July 2013. Length–weight relationship of B. falcatus in the Teles Pires River Basin can be obtained by the expression: Wt = 0.0091*SL^3.376, r² = .97, n = 102, and length‐length relationship: TL = 1.128*SL + 3.978, r² = .96. The condition factor of all specimens collected in the Teles Pires Basin was k = 1.055. Size at capable phase (L50) of spawning was estimated at 23 cm standard length. Results showed no significant difference in the length–weight relationship or condition factor of B. falcatus collected from rivers with or without soybean attractant. Concluded is that the in situ supply of soybean as a fish attractant does not interfere with the wellbeing of B. Falcatus in the Teles Pires River Basin.     

Population responses of two omnivorous fish species to impoundment of a Brazilian tropical river

Brycon gouldingi and B. falcatus were the most abundant and widespread of five species of the genus captured in a sampling study encompassing 5 years (1995–2000) in the upper Rio Tocantins, where the river was impounded by the Serra da Mesa hydroelectric dam. Given that impoundments constitute a disturbance to which species will show demographic and biological responses, we assessed such responses of these two omnivorous fishes, whose genus is regarded as vulnerable to impoundments. Both species increased greatly in numbers during the initial reservoir filling period. Brycon gouldingi had higher abundance values than B. falcatus in all sampling months, except in the pre-impoundment period. Both species showed a significant weight increment relative to body length during the time they remained in the reservoir. No reproductive individuals of B. gouldingi were recorded in the study area, but those few of Brycon falcatus were found in both wet and dry seasons, suggesting a more opportunistic strategy of reproduction. Both species were omnivorous and overlapped broadly in diet. The proportions of dietary items, however, varied in relation to fish size class and water dynamics (lotic versus lentic sites). Terrestrial arthropods composed a larger proportion of the diet of smaller-sized individuals and those from lentic sites, whereas seeds and fruits contributed more to the diet of both larger-sized individuals and those from lotic environments. Except for fish and aquatic heteropterans, which were consumed mainly in the reservoir, all other food items were allochthonous, indicating the dependence of these two species of Brycon on the terrestrial environment. The two species responded similarly to the alterations imposed by the impoundment of the upper Tocantins, although reproduction/recruitment pattern was slightly different between species. As observed in other regions of Brazil, impoundments and deforestation appear to produce negative cumulative effects on species of Brycon. These impacts call for greater efforts to conserve and manage members of this diverse and widespread genus. Handling editor: S.M. Thomaz     

Exercise‐Induced Reduction in Obesity and Insulin Resistance in Women: a Randomized Controlled Trial

Objectives : To determine the effects of equivalent diet‐ or exercise‐induced weight loss and exercise without weight loss on subcutaneous fat, visceral fat, and insulin sensitivity in obese women. Research Methods and Procedures : Fifty‐four premenopausal women with abdominal obesity [waist circumference 110.1 ± 5.8 cm (mean ± SD)] (BMI 31.3 ± 2.0 kg/m²) were randomly assigned to one of four groups: diet weight loss (n = 15), exercise weight loss (n = 17), exercise without weight loss (n = 12), and a weight‐stable control group (n = 10). All groups underwent a 14‐week intervention. Results : Body weight decreased by ～6.5% within both weight loss groups and was unchanged in the exercise without weight loss and control groups. In comparison with controls, cardiorespiratory fitness improved within the exercise groups only (p < 0.01). Reduction in total, abdominal, and abdominal subcutaneous fat within the exercise weight loss group was greater (p < 0.001) than within all other groups. The reduction in total and abdominal fat within the diet weight loss and exercise without weight loss groups was greater than within controls (p < 0.001) but not different from each other (p > 0.05). Visceral fat decreased within all treatment groups (p < 0.008), and these changes were not different from each other. In comparison with the control group, insulin sensitivity improved within the exercise weight loss group alone (p < 0.001). Discussion : Daily exercise without caloric restriction was associated with substantial reductions in total fat, abdominal fat, visceral fat, and insulin resistance in women. Exercise without weight loss was also associated with a substantial reduction in total and abdominal obesity.     

Volatile semiochemical impact on trapping and distribution in maize of northern and western corn rootworm beetles (Coleoptera: Chrysomelidae)

Abstract 1 Field studies evaluated plant attractants and analogues as tools to move corn rootworm beetles (Diabrotica spp.) into areas to be treated with toxic baits for population suppression via mass removal/annihilation of reproductive adults. 2 When dispensed from sticky traps in maize, 2‐phenyl‐1‐ethylamine and 2‐phenyl‐1‐ethanol captured more northern corn rootworm, Diabrotica barberi, than did 4‐methoxyphenethanol. Only 2‐phenyl‐1‐ethanol attracted the western corn rootworm, Diabrotica virgifera virgifera, but not until maize matured beyond milk stage. 3 Attraction of D. barberi to the amine, alone or blended with 2‐phenyl‐1‐ethanol, occurred before and after maize flowered but not during intervening silk or blister stages. Attraction recurred during early milk stage at or before 50% emergence of adult female D. barberi or D. v. virgifera, respectively, and before populations declined for the season. 4 Synergistic interaction of 2‐phenyl‐1‐ethylamine with 2‐phenyl‐1‐ethanol in attracting D. barberi females did not occur until maize matured to late milk stage. 5 The amine‐alcohol blend (0.44 point sources m^?2) doubled the density of D. barberi but not D. v. virgifera when applied to small plots within mostly milk‐stage or younger maize. Traps without bait within attractant‐treated plots captured more female, but not male, D. barberi than did traps in untreated control plots, hinting that females accounted for most of the observed increase in beetle density. 6 The results suggest that attractants can be used despite phenological limitations to concentrate preovipositional females within field areas and thus to complement a variety of corn rootworm control strategies.     

Big Fish are the Best: Seed Dispersal of Bactris glaucescens by the Pacu Fish (Piaractus mesopotamicus) in the Pantanal, Brazil

We studied the potential role as seed disperser of the pacu fish (Piaractus mesopotamicus, Characidae) in the Pantanal of Brazil. The most important food item in the diet of the pacu in the wet season was fruits of the palm Bactris glaucescens found in the guts of 73 percent of all fishes collected (N= 70). We found a positive relationship between fish length, weight, and gape size and the number of intact seeds in their gut. Therefore, large pacus are especially important in dispersing B. glaucescens seeds within the studied system. Since the best seed dispersers are the largest fishes, which are preferred by commercial fisheries, we predict that the ongoing over fishing in freshwater ecosystems will have major impacts on the dispersal system of fish‐dependent plants. We suggest that it is paramount to change the attitudes in fisheries management of fruit‐eating fishes and urgent to evaluate the impact of fishing on forest regeneration.     

Diet of an endangered Neotropical catfish (Kalyptodoras bahiensis) from the Paraguaçu River,Bahia, Brazil

ABSTRACT

The present study investigates the diet composition and the feeding strategy of Kalyptodoras bahiensis by verifying variations during the hydrological cycle and between males and females. Samples were collected during the periods of rain and drought using various fishing gears adapted to each microhabitat. In laboratory, the fishes were weighed and measured. An abdominal incision was made to observe the gonads for sex determination and the stomach was removed for identification and quantification of food items. The importance of each item in the diet was calculated using the Feeding Index. Amundsen graphic analysis was used to define the feeding strategy. Kalyptodoras bahiensis was classified as an omnivorous species with an invertivorous tendency. The species presented a generalist feeding strategy and many individuals fed on Melanoides tuberculatus, an exotic mollusk that has spread to Brazilian rivers, causing damages to the native community. The high amount and frequency of M. tuberculatus in the diet of K. bahiensis suggest that the species may have a predatory impact on the local population of this mollusk. However, further studies are needed to better understand the interaction between K. bahiensis and M. tuberculatus.     

Reversal of Small,Dense LDL Subclass Phenotype by Weight Loss Is Associated With Impaired Fat Oxidation

Adiposity is more prevalent among individuals with a predominance of small, dense low‐density lipoprotein (LDL) (pattern B) particles than among those with larger LDL (pattern A). We tested for differences in resting energy expenditure (REE) and respiratory quotient (RQ) in overweight men with pattern A (n = 36) or pattern B (n = 60). Men consumed a standardized isoenergetic diet for 3 weeks after which a ～9 kg weight loss was induced by caloric deficit for 9 weeks, followed by 4 weeks of weight stabilization. REE and RQ were measured by indirect calorimetry before and after weight loss. Results were analyzed separately in pattern B men who converted to pattern A (B→A; n = 35) and those who did not (B→B; n = 25). At baseline, B→B men had higher trunk fat, triacylglycerol (TG) and insulin concentrations, homeostasis model assessment of insulin resistance (HOMA_IR), and smaller LDL particles compared to B→A men and baseline pattern A men who remained pattern A (A→A; n = 35). REE normalized to fat‐free mass did not change after weight loss. RQ decreased in A→A men, increased in B→A men, and did not change significantly in B→B men after weight loss. Calculated fat oxidation rates paralleled the RQ results. Baseline plasma TG concentrations were positively correlated with RQ and inversely correlated with the magnitude of weight loss achieved for a given prescribed energy reduction in the entire study population. Pattern B men who converted to pattern A with weight loss may have an underlying impairment in fat oxidation that predisposes to both dyslipidemia and an impaired ability to achieve weight loss by energy restriction.     

Intra-abdominal fat burden discriminated in vivo using proton magnetic resonance spectroscopy

Objective: To assess proton magnetic resonance spectroscopy (¹H‐MRS) as a means to distinguish among mice with disparate intra‐abdominal body fat compositions, and to measure changes in intra‐abdominal fat burden during weight loss and regain. Research Methods and Procedures: Intra‐abdominal fat burden was analyzed as a ratio of integrated areas under the curves of fat to water ¹H‐MRS signals collected from a region of interest standardized across B6.V‐Lep^ob, C57BL/6, and A‐ZIP/F mice that exhibited various genotypically related body fat compositions, ranging from obese (B6.V‐Lep^ob) to minimal body fat (A‐ZIP/F). ¹H‐MRS analysis of fat burden was compared with intra‐abdominal fat volume and with a single cross‐sectional intra‐abdominal fat area calculated from segmented magnetic resonance images. Similar measurements were made from obese B6.V‐Lep^ob mice before, during, and after they were induced to lose weight by leptin administration. Results: Relative amounts of intra‐abdominal fat analyzed by ¹H‐MRS differed significantly according to body composition and genotype of the three strains of mice (p < 0.05). Intra‐abdominal fat assessed by ¹H‐MRS correlated with both intra‐abdominal fat volume (r = 0.88, p < 0.001) and body weight (r = 0.82, p < 0.001) among, but not within, all three genotypes. During weight loss and regain, there was a significant overall pattern of changes in intra‐abdominal fat quantity that occurred, which was reflected by ¹H‐MRS (p = 0.006). Discussion: Results support the use of localized ¹H‐MRS for assessing differences in intra‐abdominal fat. Refinements in ¹H‐MRS voxel region of interest size and location as well as instrument precision may result in improved correlations within certain body compositions.     

Effects of Weight Cycling Induced by Diet Cycling in Rats Differing in Susceptibility to Dietary Obesity

LAUER, JOAN B., GEORGE W. REED, AND JAMES O. HILL. Effects of weight cycling induced by diet cycling in rats differing in susceptibility to dietary obesity. Obes Res. Objective Although the majority of evidence in rodents does not support the view that weight cycling (consisting of bouts of food restriction and refeeding) promotes obesity, the effects of weight cycling on body weight regulation remain controversial. We have previously demonstrated that some rats within a strain are more susceptible to develop obesity than others when given free access to a high-fat diet. In this study, we tested the hypothesis that rats most susceptible to weight gain on a high-fat diet would also be most susceptible to weight gain as a consequence of weight cycling. Research Methods and Procedures Rats were provided a low-fat diet (12% corn oil) for 2 weeks, then given a high-fat diet (45% corn oil) for 2 weeks to identify those most (obesity prone) and least (obesity resistant) susceptible to weight gain. Half of each group was then subjected to three 30-day cycles of food restriction (10 days) and refeeding (20 days) [weight cycler (WC) rats]. The other half were allowed free access to the high-fat diet [control (CO) rats]. All rats were then followed for an additional 10 weeks, with free access to the high-fat diet. Results When considering the entire 160 days of the study, we found no evidence that WC rats relative to CO rats had increased body weight, increased body fat content, or elevated energy efficiency. We found no evidence that rats most prone to dietary obesity were also prone to weight gain after weight cycling. During the weight cycling phase (days 1 to 90), weight cycled groups consumed less energy and gained less weight than controls. During the follow-up phase, WC and CO rats did not differ significantly in weight gain or energy intake. Discussion In this study, weight cycling did not exacerbate the obesity produced by high-fat diet feeding.     

Effects of dietary lactose on long-term high-fat-diet-induced obesity in rats

Objective: In this study, we examined the effects of lactose on long‐term high‐fat‐diet‐induced obesity in rats. Research Methods and Procedures: A total of 112 Sprague‐Dawley strain female rats (6 weeks old) were divided into four groups: a basic control diet group (Cont), 10% lactose diet group (Lac), high‐fat diet group (Fat), and high‐fat with 10% lactose diet group (Fat+Lac). After 0, 7, 14, and 84 days from starting the experimental diet, the animals were fasted overnight and killed by bleeding from the abdominal aorta under anesthesia (n = 8 or 9/group). Results: After 84 days, the addition of lactose to the high‐fat diet decreased the final body weight, body weight gain, fat accumulation, and the levels of serum leptin, serum triglycerides, and serum glucose significantly (p < 0.05). Although there was no significant difference in the levels of serum calcium and phosphorus between the Fat and Fat+Lac groups, lumbar vertebral bone mineral density was significantly higher in the Fat+Lac group than in the Cont group on Day 82. Interestingly, the level of serum 1α, 25‐dihydroxyvitamin D₃ in the Fat+Lac group on Day 84 was reduced by 74% compared with the Fat group (p < 0.01), while there was no significant difference in serum parathyroid hormone levels between the Fat and Fat+Lac groups. Discussion: This is the first study to suggest that the addition of lactose to a long‐term high‐fat diet may regulate not only calcium metabolism but also fat deposition. Further studies on the mechanism of dietary lactose in the regulation of adiposity would provide valuable data for the prevention of long‐term high‐fat‐diet‐induced obesity.     

Biology of fork-tailed catfishes from the Sepik River,Papua New Guinea

Synopsis Ariids accounted for approximately 25% of the weight of catches and landings from rivers and lakes in the floodplain region (= 50% weight of native species). Habitat preferences were:A. solidus, lakes and rivers;A. utarus, rivers and occasionally lakes;A. coatesi andA. velutinus, rivers only;A. nox, lakes and floodplain.A. solidus andA. utarus occasionally entered the floodplain but onlyA. nox exhibited any, albeit modest, affinity for this environment. In general, the fishes showed no marked seasonality relating to the flood cycle: in four species slight increases in feeding, condition, breeding and fat deposition occurred during the dry season whilst onlyA. nox showed modest increases in these parameters during the flood season due to its increased feeding on the floodplain at that time. All species are omnivorous but diets differed according to morphology and habitat preferences. Diet overlap was greatest amongstA. coatesi, A. solidus andA. utarus which fed mainly on prawns and a variety of other plant and animal matter.A. nox is a specialised filter-feeder consuming mainly small crustaceans and small insect larvae.A. velutinus fed mainly on large insect larvae and emergent and terrestrial insects and its diet excluded prawns.A. solidus and, especially,A. utarus also fed on fish scales. Feeding commenced immediately after hatching while free embryos were still in the male parent's mouth. Large amounts of fat were stored prior to brooding during which time males fast. The reproductive style of ariid catfishes limits their colonisation of the floodplain and is a constraint to increased fisheries exploitation of the stocks. The importance of ariids to the local fishery and nutrition (fat) for the local people should be recognised.     

Canola,corn, and vegetable oils as alternatives for wheat germ oil in fruit fly larval diets

Four wheat germ oil alternatives (corn oil, vegetable oil, canola oil with 10% vitamin E, and canola oil with 20% vitamin E), purchased from a local supermarket in Hawaii, were added to a fruit fly liquid larval diet as a replacement for wheat germ oil in the rearing of fruit fly larvae. The oils were tested on three species of fruit flies in Hawaii, Ceratitis capitata (TSL strain), Bactrocera dorsalis, and Bactrocera cucurbitae. They were evaluated for their efficacy in replacing WGO, based on: pupal recovery (%), larval duration (d), pupal weight (mg), adult emergence (%), adult fliers (%), mating (%), egg production per female per day, egg hatch (%), and peak egging period (d). Diets with WGO and without any oil were used as controls. The objective of the study was to select the most cost effective alternative oils with the best performance to replace the currently used WGO, which is pricey and hard to find. The results showed that there was no significant difference in performance among the tested oils in B. cucurbitae and B. dorsalis as regards the above mentioned parameters. Lower mating rate was observed in B. cucurbitae from those reared in vegetable oil and canola oil (10% vitamin E) diet. Lower egg production and egg hatch were obtained with B. dorsalis whose larvae were reared in vegetable and canola oil (both 10% and 20% vitamin E). Vegetable oil diet seemed to reduce pupal weight, shorten larval duration, and increase pupal recovery of C. capitata. The results suggest that WGO can be substituted with corn oil, vegetable oil, or canola oils for B. cucurbitae, while corn oil is a better alternative for B. dorsalis, and vegetable oil is best for C. capitata.     

Relationship of Heliothis zea predators, parasitoids and entomopathogens to canopy development in soybean as affected by Heterodera glycines and weeds

The influence of canopy development in soybean on the survival of corn earworm, Heliothis zea (Boddie) (Lepidoptera: Noctuidae), egg and larval stages and population dynamics of arthropod fauna were evaluated in field trials during 1986–88 in eastern North Carolina. Soybean canopy size decreased as soybean cyst nematode, Heterodera glycines Ichinohe (Nematoda: Heteroderidae), initial population densities increased. Plant species composition of the soybean canopy was affected by weed population densities. Mortality of H. zea larvae due to parasitism and infection with entomopathogens was greater in closed canopy and (or) weedy soybeans than in very open and (or) weed free soybeans. Predation and parasitism of corn earworm eggs were similar across nematode and weed density treatments. Natural enemy populations increased to highest levels during July in closed canopy and (or) weedy soybeans, coinciding with availability of largest prey population reservoirs. A delay in colonization of very open and (or) weed free soybeans by beneficial arthropods until mid to late August allowed greater H. zea larval survival than in closed canopy and (or) weedy soybeans. Arthropod species richness was generally greatest in closed canopy and (or) weedy soybeans during mid to late July, with differences becoming nonsignificant in August and early September. Mean and maximum ambient temperatures were higher and relative humidities lower in open canopy than in closed canopy plots. These conditions were less favorable for development of pathogens and natural enemies.     

Trans fat diet induces abdominal obesity and changes in insulin sensitivity in monkeys

Objective: There is conflicting evidence about the propensity of trans fatty acids (TFAs) to cause obesity and insulin resistance. The effect of moderately high intake of dietary monounsaturated TFAs on body composition and indices of glucose metabolism was evaluated to determine any pro‐diabetic effect in the absence of weight gain. Research Methods and Procedures: Male African green monkeys (Chlorocebus aethiops; n = 42) were assigned to diets containing either cis‐monounsaturated fatty acids or an equivalent diet containing the trans‐isomers (～8% of energy) for 6 years. Total calories were supplied to provide maintenance energy requirements and were intended to not promote weight gain. Longitudinal body weight and abdominal fat distribution by computed tomography scan analysis at 6 years of study are reported. Fasting plasma insulin, glucose, and fructosamine concentrations were measured. Postprandial insulin and glucose concentrations, and insulin‐stimulated serine/threonine protein kinase (Akt), insulin receptor activation, and tumor necrosis factor‐α concentrations in subcutaneous fat and muscle were measured in subsets of animals. Results: TFA‐fed monkeys gained significant weight with increased intra‐abdominal fat deposition. Impaired glucose disposal was implied by significant postprandial hyperinsulinemia, elevated fructosamine, and trends toward higher glucose concentrations. Significant reduction in muscle Akt phosphorylation from the TFA‐fed monkeys suggested a mechanism for these changes in carbohydrate metabolism. Discussion: Under controlled feeding conditions, long‐term TFA consumption was an independent factor in weight gain. TFAs enhanced intra‐abdominal deposition of fat, even in the absence of caloric excess, and were associated with insulin resistance, with evidence that there is impaired post‐insulin receptor binding signal transduction.     

Adult Female Rats Defend “Appropriate” Energy Intake after Adaptation to Dietary Energy

Objective: To determine if adult female rats adapt to lower and higher dietary energy density. Research Methods and Procedures: Study 1 compared high‐fat (56%), high‐energy density (HD) (21.6 kJ/g) and high‐fat (56%), low‐energy density (LD) (16.0 kJ/g) diets before surgery (two groups, 2 weeks, n = 16) and after surgery [ovariectomy (O) Sham (S); 2 × 2 factorial, n = 8; 6 weeks]. The second study (no surgery) compared high‐fat (60.0%), high‐energy (22.0 kJ/g) and low‐fat (10.0%), low‐energy (15.1 kJ/g) diets (n = 8). Results: In study 1, food intake was similar for the first 2 weeks, but rats on the LD diet consumed less energy, gained less weight, and had lower nonfasted serum leptin (all p < 0.0001) than rats on the HD diet. After surgery, rats on the LD and HD diets had similar weight gain, but rats on the LD diet consumed more food (p < 0.0001) and less energy (p < 0.009). O rats consumed more food and gained more weight (p < 0.0001) than S rats. Results from study 2 were similar to those from study 1. Discussion: The results demonstrated that O and S surgery rats and rats with no surgery adjust their food intake to defend a level of energy intake. This defense only occurred after a 2‐week adaptation period. The major differences in final body weights and abdominal fat resulted from the initial 2 weeks before adaptation to energy density. Rats fed higher‐energy diets seemed to “settle” at a higher level of adiposity, and rats fed lower‐energy diets consumed more food to increase energy consumption.     

Mycobacterium avium subspecies paratuberculosis is widely distributed in British soils and waters: implications for animal and human health

In the first comprehensive geographical survey of distribution in Great Britain, Mycobacterium avium ssp. paratuberculosis (MAP) was detected in 115 of 1092 (10.5%) soil cores, in the range of 5 × 10² to 3 × 10⁶ MAP cell equivalents (CE) g^?1 wet weight soil with the majority of the positive PCR reactions (n = 75; 65%) occurring around the limit of detection (500–5000 CE g^?1 wet weight soil). The distribution of MAP significantly increased from North to South and was significantly correlated with increasing cattle numbers over the same longitudinal axis. Similarly MAP occurrence significantly increased towards easterly latitudes although none of the parameters measured were associated. Comparisons of land use indicated that MAP was widely distributed in both farming and non‐farming areas. Soil core samples taken from the rivers Wyre and Douglas catchments (Lancashire, UK) and river Tywi (South Wales) were negative for MAP. However, river monitoring showed a consistent presence of MAPs throughout those catchments over a 6‐month period. We concluded that MAP is widely distributed within and outside the confines of the farming environment; its geographical distribution is wider than originally anticipated and; monitoring rivers describes the MAP status of catchment better than individual soil samples.     

Diet‐Induced Changes in Stearoyl‐CoA Desaturase 1 Expression in Obesity‐Prone and ‐Resistant Mice

Objective: To investigate stearoyl‐coenzyme A desaturase (SCD) 1 expression in obesity‐prone C57BL/6 mice and in obesity‐resistant FVB mice to explore the relationship of SCD1 expression and susceptibility to diet‐induced obesity. Research Methods and Procedures: Nine‐week‐old C57BL/6 and FVB mice were fed either a high‐ or low‐fat diet for 8 weeks. Body weight and body composition were measured before and at weeks 4 and 8 of the study. Energy expenditure was measured at weeks 1 and 5 of the study. Hepatic SCD1 mRNA was measured at 72 hours and at the end of study. Plasma leptin and insulin concentrations were measured at the end of study. Results: When C57BL/6 mice were switched to a calorie‐dense high‐fat diet, animals gained significantly more body weight than those maintained on a low‐calorie density diet primarily due to increased fat mass accretion. Fat mass continued to accrue throughout 8 weeks of study. Increased calorie intake did not account for all weight gain. On the high‐fat diet, C57BL/6 mice decreased their energy expenditure when compared with mice fed a low‐fat diet. In response to 8 weeks of a high‐fat diet, SCD1 gene expression in liver increased >2‐fold. In contrast, feeding a high‐fat diet did not change body weight, energy expenditure, or SCD1 expression in FVB mice. Discussion: Our study showed that a high‐fat hypercaloric diet increased body adiposity first by producing hyperphagia and then by decreasing energy expenditure of mice susceptible to diet‐induced obesity. Consumption of a high‐fat diet in species predisposed to obesity selectively increased SCD1 gene expression in liver.     

Impact of Diet‐Induced Weight Loss on the Cardiac Autonomic Nervous System in Severe Obesity

Objective: To determine the impact of diet‐induced weight loss on cardiac autonomic nervous system modulation and arrhythmias in subjects with severe obesity and the influence of a high‐fat or a high‐carbohydrate diet regimen on heart rate variability in reduced‐obese individuals. Research Methods and Procedures: Eight severely obese subjects (BMI ≥ 40.0 kg/m²) underwent a 3‐month weight loss program followed by a 3‐month reduced‐weight maintenance regimen. Thereafter, each subject was admitted for an inpatient period of 17 days on two separate occasions. A high‐carbohydrate (60%) or high‐fat (55%) diet of appropriate energy content for weight maintenance was prescribed during each inpatient phase. Heart rate variability was derived from a 24‐hour Holter monitoring system in all subjects during their inpatient stay. Cardiac Holter monitoring was performed at three occasions (baseline, diet phase I, and diet phase II), including the second night of a two overnight calorimetry chamber stay. Results: After the diet regimen, there was a 10% decrease in weight. There were no significant changes in systolic and diastolic blood pressure, arrhythmias, glucose, insulin, total cholesterol, low‐density lipoprotein‐cholesterol, high‐density lipoprotein‐cholesterol, respiratory exchange ratio, and resting energy expenditure between experiments. Mean heart rate was lower after weight loss compared with baseline (p < 0.001). After weight loss, there was an increase in the parasympathetic indices of heart rate variability showing an increase in cardiac vagal modulation (all p < 0.05). Discussion: Weight loss is associated with significant improvement in autonomic cardiac modulation through enhancement of parasympathetic modulation, which clinically translates into a decrease in heart rate.     

Mammalian Visitation to Candidate Feral Swine Attractants

Abstract Few data exist regarding suitable feral swine (Sus scrofa) attractants in the United States. We compared species-specific visitation and contact rates of mammals to 11 candidate feral swine attractants at scent stations using motion-sensing digital photography to identify promising attractants. We found feral swine had greater visitation rates to apple and strawberry stations than to control stations. We recommend managers consider using strawberry attractants for feral swine-specific applications. If, however, a general feral swine attractant is needed, then apple, berry, or caramel attractants may perform well.     

Cyclic 3′,5′-AMP phosphodiesterase in Physarum polycephalum: II. Kinetic properties

The effect of several inhibitors of the enzyme cyclic 3′,5′-AMP phosphodiesterase as chemoattractants in Physarum polycephalum was examined. Of the compounds tested, 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (Roche 20-1724/001) and 1-ethyl-4-(isopropylidinehydrazino)-1H-pyrazolo-(3,4-b)-pyridine-5-carboxylic acid ethyl ester, hydrochloride (Squibb 20009) were the most potent attractants. 3-Isobutyl-1-methyl xanthine, theophylline, and morin (a flavanoid) were moderate attractants and sometimes gave negative chemotaxis at high concentrations. Cyclic 3′,5′-AMP was an effective, but not potent attractant. A repellent effect following the positive chemotactic action was sometimes observed with cyclic 3′,5′-AMP at concentrations as high as 1 · 10⁻² M. Dibutyryl cyclic AMP appeared to be a somewhat more potent attractant than cyclic 3′,5′-AMP. The 8-thiomethyl and 8-bromoderivatives of cyclic AMP, which are poorly hydrolyzed by the phosphodiesterase, were not attractants in Physarum. Possible participation of cyclic 3′,5′-AMP in the directional movement in P. polycephalum is discussed.