scholarly journals Pulsed supplies of small fish facilitate short-term intraguild predation in salmon stocked streams

Author(s):  
Koh Hasegawa ◽  
Sho Fukui

Abstract Pulsed supplies of prey organisms generally increase predator food intake. However, whether this holds true when predators and pulsed prey are in same guild (i.e., intraguild [IG] predators and prey) is unclear. IG prey may increase IG-predator food intake by providing a food source, but they may decrease food intake through competition. To test these hypotheses, we compared the food intake of white-spotted charr (Salvelinus leucomaenis) (IG predator) in streams that were stocked or unstocked with hatchery-reared masu salmon (Oncorhynchus masou) fry (IG prey) in streams in Hokkaido, Japan. One day after stocking, masu salmon fry occupied nearly 60% of the stomach contents by wet weight of white-spotted charr in stocked streams, and mean stomach content weight was six-times higher than in unstocked streams. However, predation of white-spotted charr on stocked fry was rare on other days. Acquisition of predator-avoidance behavior by stocked fry and/or a lack of accommodation by white-spotted charr to the sudden emergence of a new prey source (e.g., the charr in study sites were basically insectivorous, and their foraging behavior might have been ineffective for piscivory) may explain this time-limited intraguild predation. In days other than the first day post-stocking, food intake by white-spotted charr did not differ between stocked and unstocked streams. No effects of interspecific competition on white-spotted charr food intake were observed; this may be due to the body-size advantage of white-spotted charr and/or the low density of stocked masu-salmon fry.

1987 ◽  
Vol 44 (1) ◽  
pp. 120-129 ◽  
Author(s):  
D. L. Morantz ◽  
R. K. Sweeney ◽  
C. S. Shirvell ◽  
D. A. Longard

This study was designed to define the microhabitats selected in summer by juvenile Atlantic salmon (Salmo salar). Curves were developed describing the preference of 880 young salmon for water velocity at the fish's position (nose velocity), mean water column velocity, total water depth, and stream substrate size. Study sites were chosen in six morphologically diverse streams in Nova Scotia and New Brunswick during 1982–84. Of the four variables measured, only nose velocity chosen by both fry and parr was not significantly different among years or rivers. Atlantic salmon fry (< 65 mm) most frequently selected nose velocities between 5 and 15 cm∙s−1, small parr (65–100 mm) between 5 and 25 cm∙s−1 and large parr (> 100 mm) between 5 and 35 cm∙s−1. Apparently, juvenile salmon utilized water depths and stream substrates which varied within tolerable limits according to their availability in conjunction with preferred water velocities. Significant differences in the body shape and size of the pectoral fin of Atlantic salmon parr in different rivers did not influence the selection of nose velocities within the range of flow conditions sampled.


2005 ◽  
Vol 71 (3) ◽  
pp. 348-353 ◽  
Author(s):  
TAKAHIDE DOI ◽  
TOMOYUKI NAKAMURA ◽  
MASASHI YOKOTA ◽  
TAKASHI MARUYAMA ◽  
SEIICHI WATANABE ◽  
...  

2020 ◽  
Vol 20 (8) ◽  
pp. 1262-1267
Author(s):  
Haojun Yang ◽  
Hanyang Liu ◽  
YuWen Jiao ◽  
Jun Qian

Background: G protein-coupled bile acid receptor (TGR5) is involved in a number of metabolic diseases. The aim of this study was to identify the role of TGR5 after Roux-en-Y gastric bypass (GBP). Methods: Wild type and TGR5 knockout mice (tgr5-/-) were fed a high-fat diet (HFD) to establish the obesity model. GBP was performed. The changes in body weight and food intake were measured. The levels of TGR5 and peptide YY (PYY) were evaluated by RT-PCR, Western blot, and ELISA. Moreover, the L-cells were separated from wild type and tgr5-/- mice. The levels of PYY in L-cells were evaluated by ELISA. Results: The body weights were significantly decreased after GBP in wild type mice (p<0.05), but not tgr5-/- mice (p>0.05). Food intake was reduced after GBP in wild type mice, but also not significantly affected in tgr5-/- mice (p>0.05). The levels of PYY were significantly increased after GBP compared with the sham group (p<0.05); however, in tgr5-/- mice the expression of PYY was not significantly affected (p>0.05). After INT-777 stimulation in L-cells obtained from murine intestines, the levels of PYY were significantly increased in L-cells tgr5+/+ (p<0.05). Conclusion: Our study suggests that GBP up-regulated the expression of TGR5 in murine intestines, and increased the levels of PYY, which further reduced food intake and decreased the body weight.


2020 ◽  
Vol 20 (3) ◽  
pp. 446-452
Author(s):  
Seyed S. Mortazavi-Jahromi ◽  
Shahab Alizadeh ◽  
Mohammad H. Javanbakht ◽  
Abbas Mirshafiey

Background: This study aimed to investigate the effects of guluronic acid (G2013) on blood sugar, insulin, and gene expression profile of oxLDL receptors (SR-A, CD36, LOX-1, and CD68) in the experimental model of diabetes. Methods: 18 Sprague Dawley rats were randomly assigned to three groups of healthy control, diabetic control, and G2013 group. Diabetes was induced through intraperitoneal (IP) injection of 60 mg/kg streptozotocin. The subjects were IP treated with 25 mg/kg of G2013 per day for 28 days. The body weight, food intake, fasting blood glucose and insulin were measured. In addition, the expression of mentioned genes was investigated through quantitative real-time PCR. Results: The data showed that the final weight increased significantly in the G2013-treated subjects compared to the diabetic control (p < 0.05). The results indicated that final food intake significantly reduced in the G2013-treated subjects compared to the diabetic control (p < 0.05). The study findings also suggested that the final fasting blood glucose significantly reduced in the G2013-treated group, whereas the final fasting serum insulin level significantly increased in this group compared to the diabetic control (p < 0.05). Moreover, the gene expression levels of SR-A, CD36, LOX-1, and CD68 in the G2013 group significantly reduced compared to the diabetic control (p < 0.05). Conclusion: This study showed that G2013, could reduce blood glucose and increase insulin levels and reduce the gene expression level of oxLDL receptors. In addition, it may probably play an important role in reducing the severity of diabetes-induced inflammatory symptoms.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takashi Nakamura ◽  
Mai Nampei ◽  
Takayo Murase ◽  
Etsuko Satoh ◽  
Seigo Akari ◽  
...  

AbstractPlasma xanthine oxidoreductase (XOR) activity is high in metabolic disorders such as diabetic mellitus, obesity, or overweight. Thus, this study investigated whether the XOR inhibitor, topiroxostat, affected body weight. Male db/db mice were fed standard diets with or without topiroxostat for 4 weeks. Body weight and food intake were constantly monitored, along with monitoring plasma biochemical markers, including insulin and XOR activity. Additionally, hepatic hypoxanthine and XOR activity were also documented. Single regression analysis was performed to determine the mechanism. Topiroxostat treatment suppressed weight gain relative to the vehicle without any impact on food intake. However, the weight of fat pads and hepatic and muscle triglyceride content did not change. Topiroxostat decreased the plasma uric acid and increased hepatic hypoxanthine in response to the inhibition of XOR activity. Plasma ketone body and free fatty acid were also increased. Moreover, fat weight was weakly associated with plasma XOR activity in the diabetic state and was negatively associated with ketone body by topiroxostat. These results suggested that topiroxostat amplified the burning of lipids and the salvage pathway, resulting in predisposing the body toward catabolism. The inhibition of plasma XOR activity may contribute to weight loss.


1993 ◽  
Vol 38 (7) ◽  
pp. 469-471 ◽  
Author(s):  
Clifford W. Sharp

A woman aged 58 who has been blind since the age of nine months presented with major depression and a 40 year history of an eating disorder characterized by a restriction of food intake and body disparagement. The case is additional evidence that a specifically visual body image is not essential for the development of anorexia nervosa and supports the view that the concept of body image is unnecessary and unproductive in eating disorders. Greater emphasis should be placed on attitudes and feelings toward the body, and the possibility of an eating disorder should be considered in cases of older women with an atypical presentation.


1957 ◽  
Vol 188 (3) ◽  
pp. 435-438 ◽  
Author(s):  
M. J. Fregly ◽  
N. B. Marshall ◽  
J. Mayer

Goldthioglucose-obese mice cannot adjust their food intake to meet the increased energy requirements due to cold. At all ambient temperatures above 15°C the spontaneous running activity of these animals is less than that observed for nonobese controls. Activity of obese mice is maximal at 19°C and minimal at 15°C or lower. Body weights decrease during exposure to cold. In contrast to that of obese mice, running activity of nonobese controls is maximal at an ambient temperature of 25°C but nearly ceases at 15°C or lower. The food intake of these animals increases in the cold and remains elevated even at temperatures at which activity decreases. The body weight of nonobese controls is either maintained constant or increases during exposure to cold air.


1987 ◽  
Vol 45 (2) ◽  
pp. 239-260 ◽  
Author(s):  
M. L. Thonney ◽  
St C. S. Taylor ◽  
T. H. McClelland

ABSTRACTGenetic size-scaling accounts for most of the variation found among mammalian species in food intake and growth rate, with food conversion efficiency independent of the body size of the species. Is the same true of breeds and strains within species?Animals from Soay, Welsh Mountain, Southdown, Finish Landrace, Jacob, Wiltshire Horn and Oxford Down sheep breeds and from a breed of feral goats were grown to 0·40, 0·52, 0·64 or 0·76 of the mean mature weight of their breed and sex. Food was offered ad libitum and individually recorded.Allometric growth coefficients were obtained for fleece weight, femur weight and femur length. Fleece was late maturing and femur early.Breed and sex size-scaling coefficients, obtained by regression of breed and sex means on mature size, were similar to those found at the species level for age from conception to slaughter, time taken to mature and food conversion efficiency. Coefficients were higher than expected for total and daily food consumption, especially at early stages of maturity. Most breed coefficients were close to expectation while sex coefficients were somewhat higher than expected.There were significant breed deviations: Welsh Mountain, Oxford Down and probably Soay sheep required less time and Jacob sheep and feral goats required more time to mature than expected from differences in mature size. Soay and Welsh Mountain sheep appeared to be more efficient and feral goats and Jacob sheep less efficient food converters over the same maturity interval.


2018 ◽  
Vol 7 (1) ◽  
pp. 11
Author(s):  
Muhammad Hermansyah ◽  
M. Imron Mas'ud

<p><em>Many companies often pay less attention to the health of their employees during the work, it can seen from the number of employees exposed to the risk of diseases or health problems in retirement due to the imbalance between the needs of body and energy consumption that can lead to decreased productivity, especially labor-intensive companies one of them on the CV. X. The purpose of this study is to calculate the number of calories needed healthy body for employees of transport workers to regulate the pattern of food intake of the right transport workers so that caloric needs can be met. Data is collected by interview, observation and documentation study. The results showed that the work performed by transport workers was 1.5 hours including heavy work, 5 hours of moderate work and 1.5 hours of rest with an average caloric needs of 1253,601 cal / 8 hours of work, the body will experience a lack of calories when they work more or less about 6.5% (106,8576 cal / 8jam) of food they have eaten daily, then improved the food menu with an average of 1284,013 cal / 8 hours, an increase of 9.63% with the ratio of work productivity from before the improvement of 73.99% to 74.81%, resulting in an increase of 0.81%, implying on the convenience of laborers</em></p>


2018 ◽  
Vol 10 (10) ◽  
pp. 12382-12388 ◽  
Author(s):  
Syed Asrafuzzaman ◽  
Susmita Mahapatra ◽  
Jasmin Rout ◽  
Gunanidhi Sahoo

Anuran tadpoles are gregarious predators capable of differentiating food items among diverse types of prey via varied feeding and oral structures.  Tadpoles were collected from different study sites in three districts of northern Odisha during three consecutive rainy seasons (from July–October of 2015–2017).  After morphometric measurements (total length and body length), the stomach contents of 75 tadpoles belonging to five different anuran species (Duttaphrynus melanostictus, Euphlyctis cyanophlyctis, Fejervarya orissaensis, Polypedates maculatus and Microhyla ornata) belonging to four families namely Bufonidae, Dicroglossidae, Rhacophoridae and Microhylidae were examined.  The food spectrum of tadpoles included mostly detritus, followed by phytoplankton (represented by 5 classes and 54 genera).  Such studies contribute to the understanding of the natural diets of these anuran species that can assist in developing management strategies for them.  Aquatic habitats must be conserved and maintained so that conservation of anurans can be ensured.


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