Determinants of the dramatic seasonal changes in the intake of energy and protein by Japanese monkeys in a cool temperate forest

Daily intake of gross energy (DGEI) and protein (DGPI) of Japanese monkeys in a cool temperature forest were investigated in different four seasons. As a result, dramatic seasonal differences in DGEI and DGPI were found: DGEI and DGPI in winter were significantly lower than those in spring and autumn, being only about 17–42% of those in the two seasons. DGEI and DGPI in summer were also lower than those in autumn and spring, being only about 29–52% of those in the two latter seasons. Seasonal comparisons of some variables on food qualities revealed that much lower values of DGEI and DGPI in winter and summer were influenced srongly not so much by the lower calorie and protein content of food as by the lower speed of dry weight intake. Multiple regression analyses for each food item revealed that the unit weight was a more important factor in determining the speed of dry weight intake than was the speed of unit intake. In addition, the speed of dry weight intake contributed much more to the speed of calorie and protein intake than did the content of calorie and protein. Multiple regression analyses, employing DGEI and DGPI (as dependent variables) and daily mean values of some variables related to food quality (as independent variables), revealed that the mean values of speed of calorie and protein intake on food items eaten in a day could explain 79.0% and 85.9% of the variance in DGEI and DGPI, respectively. In addition, the mean value of the speed of dry weight intake of food items eaten in a day can be used to explain 74.3% and 52.8% of the variance in DGEI and DGPI, respectively. These findings suggested that not only nutritional content of food but also the speed of dry weight intake strongly determined the nutritional condition of nonhuman primates. Am. J. Primatol. 41:267–288, 1997. © 1997 Wiley-Liss, Inc.     

Age and gender differences in body composition, energy expenditure, and glucoregulation of adult rhesus monkeys

The purpose of this study was to examine the relationship of age to body composition, glucoregulation, activity, and energy expenditure in male and female rhesus monkeys. The animals were studied in three groups, young adults (YA, 7-9 years), middle-aged adults (MA, 13-17 years), and older adults (OA, > 23 years) adults. OA had a lower (P < 0.05) lean body mass than the YA and MA. OA also had the lowest values (P < 0.06) for energy expenditure (kJ/minute). Age-related differences (P < 0.05) were observed in time spent resting and moving. The OA spent the most time resting and the least time in vertical movement. There was a trend towards an age-related decrease in acute insulin response to glucose, while other glucoregulatory parameters were not changed with age. These results are similar to findings in humans, providing further evidence that the rhesus monkey is an appropriate model of human aging.     

Feeding rates,assimilation efficiencies and growth of two amphipod species on biodeposited material from zebra mussels

1. Accumulation of organic material by the zebra mussel Dreissena polymorpha is assumed to be the source of a biodeposition‐based food web. However, only little is known about the importance of the biodeposited material as a food source and its contribution to increased abundances of macroinvertebrates in the presence of D. polymorpha. 2. Feeding, assimilation and growth of the amphipods Gammarus roeselii and Dikerogammarus villosus on food sources directly and indirectly associated with D. polymorpha (biodeposited material and chironomids) and on conditioned alder leaves were measured. The stoichiometry of carbon, nitrogen and phosphorus of the diets was measured as an important determining factor of food quality. 3. Chironomids had the highest nitrogen and phosphorus contents, alder leaves were depleted in nitrogen and phosphorus, and the stoichiometry of biodeposited material was intermediate. 4. Both amphipod species had highest feeding rates and assimilation efficiencies on chironomids. Gammarus roeselii fed more on biodeposited material than on alder leaves, but assimilation efficiencies were similar; D. villosus also had similar feeding rates and assimilation efficiencies on the two diets. 5. Both amphipod species had highest growth rates on chironomids and lowest growth rates on alder leaves. Both grew at intermediate rates on biodeposited material of D. polymorpha. The growth rates of the amphipod species were related to food stoichiometry. Overall, the invasive D. villosus grew faster than the indigenous G. roeselii. 6. Food resources directly and indirectly associated with D. polymorpha are potential diets for amphipods, providing further evidence for a D. polymorpha biodeposition‐based food web.     

Compensatory growth in juvenile roach Rutilus caspicus: effect of starvation and re‐feeding on growth and digestive surface area

The aim of this study was to investigate compensatory growth in juvenile Rutilus caspicus during starvation and re‐feeding periods. The results confirmed the existence of compensatory growth in R. caspicus which depended on the duration of food deprivation. Complete compensatory growth occurred in the fish that were food deprived for at least 3 weeks. Starvation and re‐feeding had no significant effect on the digestive somatic index and intestinal surface areas in the fish that were food deprived for 1 week, while they showed a significant decrease and increase, during starvation and re‐feeding in the fish that were food deprived for 2 and 3 weeks. This knowledge may have application in aquaculture, as appropriate exploitation of compensatory growth can give increased growth rate and feeding efficiency.     

The Effect of Food Quantity on Feeding and Metabolic Expenditure in Cladocera

The effect of Chlorella concentration on total metabolic expenditure, basal metabolism and filtering and ingestion rates was studied in juvenile and adult females of three cladoceran species. No significant influence of food concentration on basal metabolism was found, whereas total metabolic expenditure depended on Chlorella concentration. Total metabolic expenditure in cladocerans was subdivided into: basal metabolism and expenditure on filtration, locomotion and specific dynamic action (SDA). Significant positive correlations were observed between expenditure on filtration and filtering rate and between expenditures on SDA and ingestion rate.     

Feeding patterns of the dominant benthic and demersal fish community in a temperate estuary

The diet and feeding relationships of the 12 most abundant benthic and demersal fish species of the Mondego Estuary, Portugal, were studied between June 2003 and May 2006. Fishes were caught during the night using a 2 m beam trawl. The stomach contents were analysed for prey identification, counting and weighing. According to prey importance in diets, three main feeding guilds were identified: (1) invertebrate feeders, (2) invertebrate and fish feeders and (3) plankton and invertebrate feeders. Besides these main feeding guilds, some fishes also presented fractions of algae and zooplankton in their stomach contents. The most abundant prey items were macroinvertebrates, with several polychaetes ( Nephtys spp., Capitellidae, Spionidae and Eunicidae), Corophium spp. and Crangon crangon among the dominant prey. Pomatoschistus spp. were the most preyed on fishes. Several fish species showed a tendency for a specialized diet, but almost all also showed some degree of opportunistic feeding by preying on other food resources. High diet overlap was found between some fish species, yet exploitative competition could not be concluded.     

光周期对白头鹎体重、器官重量和能量代谢的影响

光周期是四季环境变化的最直接表现因素之一,并影响动物的生理变化特征。为探讨光周期驯化对白头鹎(Pycnonotussinensis)体重、器官重量及能量代谢的影响,以室温28℃、不同光周期(16L∶8D,LD组和8L∶16D,SD组)对两组白头鹎进行为期4周的光周期驯化,测定其体重、各器官鲜重和干重、基础代谢率(BMR)和食物摄入能、排泄能及同化能并计算同化率。结果发现,SD组个体体重、内部器官(肝、小肠)重量、BMR及同化率相应显著高于LD组个体;短光照刺激白头鹎显著降低摄入能、排泄能及同化能。这些结果表明:光周期对白头鹎的体重、器官重量、BMR及能量收支有着一定影响,并且短光照较长光照更能引起白头鹎体重、器官重量及能量代谢的明显变化,同时验证了中心限制假说,即白头鹎BMR与中心器官代谢(肝、小肠等)具有相关性,中心器官是改变白头鹎BMR的主要原因之一。     

Inter‐individual differences in rates of routine energy loss and growth in young‐of‐the‐year juvenile Atlantic cod

Inter‐individual differences in rates of routine (non‐feeding) metabolism and growth were evaluated in young‐of‐the‐year (YOY) juvenile Atlantic cod Gadus morhua . Rates of O₂ consumption, CO₂ production and ammonia (TAN) excretion were measured in 64, 25–43 mm standard length ( L _S) YOY growing at different rates (0·27–0·47 mm day⁻¹) in a common rearing tank. Parameter rates ( y ) increased allometrically ( y = a·M^b ) with increasing body mass ( M ) with b ‐values for O₂ production, CO₂ consumption and TAN excretion equal to 0·81, 0·89 and 0·56, respectively. In some cases, residuals from these regressions were significantly negatively correlated to fish growth rate. In no cases did residuals of parameter rates increase with increasing growth rate. These data suggest that, during unfed periods, relatively fast‐growing fish were more metabolically efficient than slower‐growing fish from the same cohort. The fish condition factor, derived from     , also significantly decreased with increasing growth rate. Results indicated differences in both the rates of routine energy loss and the patterns of growth allocation among YOY Atlantic cod. Since these physiological attributes were positively correlated with growth rate, they may be indicative of 'survivors' in field populations.     

Feeding and daily ration of the chum salmon <Emphasis Type="Italic">Oncorhynchus keta</Emphasis> in the western Bering Sea in the summer-fall of 2004

This study was based on data on the feeding of the chum salmon Oncorhynchus keta sampled at daily stations in areas of the Navarin Shelf and Aleutian Basin in the Bering Sea in August and September 2004. The food composition and daily dynamics of chum feeding were investigated. The rate of food evacuation from the stomach and the amount of the daily diet were estimated. The distinctions in the feeding patterns of chum sampled from different areas were considered. In the Navarin Shelf area the chumís prey were primarily nekton species (mostly Alaskan pollack underyearlings) and the amount of the daily diet for chum of various size groups was 1.8–3.8% of their body weight. In the deep-water Aleutian Basin, the daily dynamics of chum feeding depended on migration of euphausiids, amphipods and mesopelagic fishes to the surface water layers of epipelagics during the night. The daily ration for chum that fed mainly on plankton did not exceed 2.6–2.8% of their body weight in August and 1.2–2.5% in September.     

The effects of feeding regime on proximate body composition and patterns of energy deposition in juvenile Arctic charr, Salvelinus alpinus

Juvenile Arctic charr, Salvelinus alpinus , subjected to either food deprivation or restricted feeding showed reductions in relative sizes of both liver and viscera. With food deprivation, percentage lipid decreased and percentage water increased in the eviscerated carcass, which is in agreement with findings for several other fish species. Following transfer from a restricted to a satiation feeding regime, the relative sizes of both liver and viscera increased to levels exceeding those of fish fed continuously to satiation. At the end of the experiment the percentage liver lipid content of restricted-satiation fed fish was higher than in fish fed to satiation. These differences in energy deposition patterns were, however, not sufficiently large to produce marked differences at the whole animal level, since whole body lipid energy: protein energy ratios and energy utilization efficiencies were similar for restricted-satiation and satiation fed fish.     

Feeding ecology of larval and juvenile black seabream (Acanthopagrus schlegeli) and Japanese seaperch (Lateolabrax japonicus) in Tolo Harbour, Hong Kong

Black seabream, Acanthopagrus schlegeli, and Japanese seaperch, Lateolabrax japonicus, are important commercial species in the coastal waters of western Pacific Ocean, including Japan, Korea and China. In Hong Kong, larvae and juveniles of these two species occur in bays and estuaries during late winter and spring. This study reports on the ontogenetic changes in food habits in larvae and juveniles of these species in an artificial rocky shore area. Copepods and cladocerans were the most numerous food items for black seabream. There was a shift to larger and benthic prey as the fishes grew. Japanese seaperch <2.1cm fed predominantly on copepods and cladocerans, while larger prey were added as fish size increased. Japanese seaperch >6.0cm were piscivorous. Maximum prey width increased with fish standard length and mouth gape width in both species. Overall, black seabream showed greater diet breadth than did Japanese seaperch. In black seabream, diet breadth increased with fish size. In Japanese seaperch, diet breadth increased with size for fishes <4.0cm, then decreased as the fishes became piscivorous. Prey selectivity in black seabream was determined using information on prey availability in plankton samples. In general, preference was stronger for cypris larvae, Penilia avirostris and decapod larvae than for copepods and podonids. In recent years, overfishing and environmental degradation have led to the decline of fish populations in Tolo Harbour. Absence of fishes with empty gut indicates that inner Tolo Harbour is still an important nursery area for these two commercial species.     

光周期对白头鹎（Pycnonotus sinensis）体重、器官重量和能量代谢的影响

光周期是四季环境变化的最直接表现因素之一,并影响动物的生理变化特征。为探讨光周期驯化对白头鹎(Pycnonotus sinensis)体重、器官重量及能量代谢的影响,以室温28℃、不同光周期 (16L ∶ 8D,LD组和8L ∶ 16D,SD组)对两组白头鹎进行为期4周的光周期驯化,测定其体重、各器官鲜重和干重、基础代谢率(BMR)和食物摄入能、排泄能及同化能并计算同化率。结果发现,SD组个体体重、内部器官(肝、小肠)重量、BMR及同化率相应显著高于LD组个体;短光照刺激白头鹎显著降低摄入能、排泄能及同化能。这些结果表明:光周期对白头鹎的体重、器官重量、BMR及能量收支有着一定影响,并且短光照较长光照更能引起白头鹎体重、器官重量及能量代谢的明显变化,同时验证了"中心限制假说",即白头鹎BMR与中心器官代谢(肝、小肠等)具有相关性,中心器官是改变白头鹎BMR的主要原因之一。     

Food and feeding habits of four species of juvenile mullet (Mugilidae) in a tidal lagoon in Ghana

Juvenile mugilid fishes, Liza falcipinnis, L. dumerilii, Mugil bananensis and M. curema , which enter the Elmina Lagoon in the Cape Coast District of Ghana, have a similar diet comprising mainly bacteria, diatoms, blue-green/green algae, protozoans, detritus and particulate organic matter. No seasonal changes in the diet and feeding activity were observed. The relative gut length (intestine to standard length ratio) and diet showed no significant changes with size of fish in all the species. All four species were diurnal feeders, but their peak feeding times differed. Interspecific competition for food was possibly limited by species preferences for substrate particles of particular size range and differences in feeding chronology.     

Feeding frequency and survival of Anopheles gambiae in a rice-growing area in Ghana

Mortality rates, determined by dissection, of predominantly M form female Anopheles gambiae (Diptera: Culicidae) were estimated. Mosquitoes were collected in tent traps and light traps in an irrigation project village in Ghana in June and July 2010, when much of the area was flooded. Both M and S form larvae were collected from rice fields (74 of 80 specimens were M form). Adults were collected in equal proportions from the two traps (90 of 107 specimens from the light trap and 106 of 116 specimens from the tent trap were M form). During the study, collection numbers rose from 105 to 972 per night. A total of 1787 of the 15 431 An. gambiae collected were dissected. Of these, 953 (53%) were found to have taken their first bloodmeal, either as virgins or following mating. The age profiles of mosquitoes collected alive and dead, respectively, were similar. Eighteen of 2933 (0.61 ± 0.49%) specimens were found to be positive for sporozoites in an enzyme-linked immunosorbent assay (ELISA). Lagged cross correlations among the different age groups implied that the mosquitoes fed on days 2 and 4 following emergence prior to oviposition and every 2.65 ± 0.17 days thereafter. The best model to describe the observed population patterns implied a daily mortality of 84%. The results are discussed in relation to possible mosquito control measures for the village.