Effects of salinity on food intake, growth, and survival of pufferfish (Fugu obscurus)

The food intake, growth, food conversion ratio and survival of yearling pufferfish, Fugu obscurus Abe, were investigated under different water salinity conditions over a 54‐day period. Within the salinity regimes of 0 (freshwater), 8, 18, and 35‰, the food intake levels were 0.97%, 1.43%, 1.19% and 1.01%, respectively; food conversion ratios were 1.31, 1.93, 1.61 and 1.36, respectively; and specific growth rates were 0.41%, 1.15%, 0.84%, and 0.35%, respectively. The three data series were reduced with increasing salinity. However, the survival rates did not show the same tendencies, which were 80%, 100%, 100%, and 67%, respectively. There were significant differences among the treatments. In conclusion, the yearling pufferfish optimum culture salinity condition was about 8‰.     

Growth, daily ration, and gastric evacuation rates of milkfish (Chanos chanos) fed supplemental diet and natural food

Growth, daily ration, and gastric evacuation rates of milkfish ( Chanos chanos ) that fed on natural food and supplement diet were evaluated. Milkfish fingerlings (5.5g) were stocked at 1.5 fish/m² in ten 12 m² concrete tanks layered with 15-cm thick earthen bottoms. All tanks were regularly fertilized (16–20–0 and chicken manure) to maintain natural food production; 4 of the tanks additionally received a supplemental diet containing 34.3% protein and 4290 kcal/kg gross energy. Estimates or daily ration (based on dry weight of stomach contents) were calculated using the E lliot and P erson (1978) and E ggers 1977) models. Gastric evacuation rate was lower in fish that fed on natural food (1.57) compared to fish fed a supplemental diet (1.79). Consequently, the lower rate resulted in lower food intake and slower fish growth. When fish were provided a high quality supplemental diet, daily rations for fingerlings (35 g) to marketable size (116 g) ranged approximately from 0.60 to 19.68 kcal/fish/day. The deviation in daily ration (kcal/fish/day) from the above estimates may indicate the insufficient quantity of dietary energy taken by fish from natural food alone, which could be provided by supplemental diet.     

Growth and food consumption of 0+ Arctic charr fed pelleted or natural food at six different temperatures

The effects of temperature and diet on the specific growth rate and food consumption of 1-summer-old Arctic charr Salvelinus alpinus were studied. Fish were reared singly in aquaria at six different constant temperatures (5, 9, 13, 16, 18 and 20°C). They were fed Neomysis integer or commercial pelleted food for 2 weeks and growth and food consumption were measured. In both experiments, growth rate increased to an optimum at 15°C. Growth rates were high in the range 13–18°C, with no significant ( P >0·05) differences between temperatures. No significant ( P> 0·05) differences in growth were found between fish at 9 and 20°C. There were no effects of diet on size-adjusted growth rates. The growth efficiency decreased with increasing temperature in both treatments, but the decrease was faster in the Neomysis treatment. Charr seemed to compensate for the high water content (79·5%) of Neomysis by having a higher food intake.     

Evidence of differences in growth and food intake regulation in different genetic strains of channel catfish

Norris and USDA-103 strains of channel catfish Ictalurus punctatus were compared for growth rate and food conversion ratio under satiation feeding and restricted feeding (1% body weight day⁻¹) regimes. At the start of the experiment Norris fish weighed 2·8 g, USDA-103 fish weighed 14·0 g. Therefore, a regression of the loge of specific growth rate against the log_e of mean body size with an empirically derived fixed slope of -0·37 was used to compare growth rates. Under both feeding regimes the USDA-103 strain had faster specific growth rates and more efficient food conversion. In subsequent studies, voluntary food intake of size matched fish (60 g average) from these two strains was compared using a radiographic method. Fish were acclimatized to tank conditions for 3 weeks prior to voluntary food intake measurement. Half of the groups were deprived of food for 2 days prior to food intake measurement, while the remaining groups were fed 1% body weight day⁻¹. The USDA-103 strain fish ate significantly more food and grew faster than the Norris strain fish. Previously fasted Norris fish subsequently ate more than their fed counterparts, whereas the fed USDA-103 fish consumed more food than the fasted USDA-103 group. When the USDA-103 strain fish were deprived of food for 4 , 2 or 0 days, all groups subsequently consumed between 4·5 and 5·0% of body weight in one meal. The USDA-103 fish, unlike the Norris fish were not stimulated to consume more after short-duration fasting. Taken together, these results suggest that there are genetic differences in growth, food conversion ratio and regulation of food intake between Norris and USDA-103 strains.     

Factors affecting the food intake, growth and protein utilization in the Helix aspersa snail. Protein content of the diet and animal age.

Food intake, growth and protein utilization were studied in the Helix aspersa snail by means of a nutritional balance experiment. This was designed in a 5 x 11 factorial arrangement involving 5 diets of different protein content (10.0, 12.5, 15.0, 17.5 and 20.0%) and 11 animal ages (ranging over 15 to 180 days of age). Dietary protein content and animal age determined food intake and protein utilization. The variations of dry matter and protein intake rates, growth rates, growth efficiency factors and protein retention rates, depending on dietary protein content or animal age were in agreement with what happens in other animals. These results suggest that there is no need to use diets with more than 17.5% of crude protein in these animals.     

Effects of textile dye stuff effluent on food utilization of Cyprinus carpio (Linn.)

Dye stuff effluent at 15% caused 100% mortality within 24 hr; 96 hr LC50 value being 10% concentration. Prolonged exposure of C. carpio to chosen sublethal concentrations (1, 3, 5, 7 or 9%) reduced the food intake and increased the maintenance cost. Exposure also caused significant reduction in growth rate and conversion efficiency; these values averaged to 11 mg/g/day and 28% in the control group (0% concentration) respectively and decreased to 0.8 mg/g/day and 4% respectively at 9% concentration.     

The relationship between size,budding rate,and growth efficiency in three species of hydra

Three species of the fresh water carnivore hydra, H. littoralis, H. pseudoligactis, and C. viridissima present a graduation in size with the first species the largest and albino Chlorohydra the smallest. When presented with a daily overabundance of food (artemia), considerable variation in food intake and gross efficiency of growth (proportion of food energy consumed that is turned into new protoplasm or buds) existed among the species. The degree of association between size of species and food intake was highly significant. However, budding efficiency among the species was found to be independent of food intake (when the effects of species size were eliminated) and of species size (when the effects of food intake were removed). However, species with high (low) efficiencies have significantly higher (lower) reproductive rates. A lowering of the temperature from 25° to 15° C. increased the size of the species, increased food intake, but decreased reproductive rate. In all species except H. pseudoligactis a corresponding increase in the production of bud energy with no change in efficiency also occurred. On the other hand, lowering of the temperature for H. pseudoligactis significantly lowered reproductive efficiency but had no effect on the total calorific output of buds. This species, in constrast to the others, appears to have a compensatory ability to adjust its efficiency to maintain a high calorific output when temperature increases. It was also found that albino Chlorohydra have budding efficiencies of around 35 percent which are not influenced by changes in food intake or light. Normal green hydras, however, have efficiencies which range from 40 to 62 percent above their albino counterparts when fed once a day and once every two days in light respectively. It it concluded first, that the symbiotic algae in the gastrodermals cells of green hydra contribute quantitatively in the order of the above amounts to the growth process in this species, and second, that green hydras have the ablity to increase their growth efficiency when food intake is reduced thus reducing the drop in calorific but output that normally occurs in the albino (control) form.     

Estimates of daily food intake by an inshore population of Pleuronectes platessa L. off eastern Anglesey, North Wales

A sequence of trawl surveys showed that the diet of plaice off eastern Anglesey was dominated by Abra alba in spring and summer, and by Pectinaria koreni in early spring and autumn. Plaice ate little food in winter. Despite the relatively small stomach in this species, plaice were able to achieve high rates of daily food intake during bouts of heavy feeding by rapidly transferring newly-ingested prey items into the anterior intestine without full gastric digestion. Seasonal daily feeding rates (percentage body weight) varied between 5 and 10% for small fish (15–20 cm total length), 3 and 12% for medium fish (20–25 cm) and 2.8 and 4.4% for large fish (30–35 cm).     

Effects of early weaning on the circadian rhythm and behavioral satiety sequence in rats

The objective of this work was to study the effect of early weaning on circadian rhythm and the behavioral satiety sequence in adult rats. Male Wistar rat pups were weaned for separation from the mother at 15 (D15), 21 (D21) and 30 (D30) days old. Body weight and food intake was measured every 30 days until pups were 150 days old. At 90 days of age, the circadian rhythm of food intake was evaluated every 4 h for three days. Behavioral satiety was evaluated at 35 and 100 days of age. This work demonstrated that body weight and food intake were not altered, but the behavioral satiety sequence demonstrated that the D15 group delayed satiety compared with the D30 group at 100 days of age. In the circadian rhythm of the food intake study, early weaning (D15) changed food intake in the intermediary period of the light phase and in the intermediary period of the dark phase. In conclusion, our study showed that early weaning may alter the feeding behavior mainly in relation to satiety and the circadian rhythm of feeding. It is possible that the presence of other environmental stimuli during early weaning can cause hyperphagia and deregulate the mechanisms of homeostasis and body weight control. This study supports theories that depict insults during early life as determinants of chronic diseases.     

Growth, feeding frequency, protein turnover, and amino acid metabolism in European lobster Homarus gammarus L

The effect of feeding frequency on growth and protein metabolism in the European lobster, Homarus gammarus, was investigated. Fourth (IV) stage lobsters H. gammarus were fed individually a marine animal meal (herring/mussels meal) for 56 days. Feeding a daily ration equivalent to 10% of their body weight gave better growth than feeding daily rations of 5% and 20%. Protein synthesis rates were similar for the three food rations but protein growth rates were significantly lower and protein degradation rates highest in the 5% body weight per day ration group. The efficiency with which synthesised protein was retained as growth was found to be 38% in the in the 10% ratio group. Protein synthesis rates of lobsters were found to be lower than those for shrimps (Penaeus vannamei). The amino acid flux also suggests a lower protein conversion efficiency than shrimps P. vannamei. The results suggests that lobsters are slow, periodic feeders and that growth can be readily increased by manipulation of particular environmental factors such as feeding frequency.     

Effects of food quality on maturation rate in Arctic charr, Salvelinus alpinus (L.)

The effects of food quality on maturation rate were followed in progeny from wild Arctic charr, caught in Lake Fattjaure, northern Sweden. The fish were reared at five different food quality levels. In the first summer, the fry were given feed of three qualities: diluted with cellulose in three proportions (0, 15 and 25%). During the second winter the impact of changed food quality level was studied by transferring half the fish from the high (control) to the low food quality level and vice versa.
Maturation rate was lower in males reared at the high and improved food quality levels than in males reared at the medium, low and reduced food quality levels. The maturation rate in females was similar at all levels, though the rate tended to increase at the reduced food quality level.
Fish reared at the high and medium levels had similar growth rates, whereas fish at the low food quality level experienced slower growth. Reduced food quality did not arrest the growth offish, whereas improved food quality enhanced their growth.     

蜜蜂春季增长阶段饲料适宜蛋白质水平的研究

早春将群势、蜂王年龄和质量基本一致的30群意大利蜜蜂Apis mellifera ligustica Spinola,随机分为5个处理组和1个对照组。处理组分别饲喂蛋白质水平为20%、25%、30%、35%和40%的5种代用花粉饲料,对照组饲喂油菜花粉,观测饲料蛋白质水平对蜂群群势、取食量、初生重以及蜂体组织蛋白含量的影响。结果表明对照组中蜜蜂对油菜花粉的取食量最高,但仅显著高于蛋白质水平为40%的饲料(P<0.05);蛋白质水平为25%、30%、35%的处理组群势增长差异不显著(P>0.05),但均显著高于对照组(P<0.05);随着饲料蛋白质水平升高,工蜂初生重逐渐升高,在35%到达最高值,随后又下降;饲喂蛋白质水平为20%、25%、30%饲料的蜂体组织蛋白含量与对照组差异不显著(P>0.05),饲喂蛋白质水平为35%、40%饲料的蜜蜂体组织蛋白含量显著高于对照组(P<0.05)。     

Effects of temperature, irradiance, and daylength on the marine diatom Leptocylindrus danicus Cleve. IV. Growth

Growth and dark respiration rates of the marine diatom Leptocylindrus danicus Cleve were measured in axenic batch culture under 49 combinations of temperature (5, 10, 15, 20°C), daylength(15:9, 12:12, 9:15 LD), and irradiance (at least four irradiances per daylength). Cell division rates exhibited a temperature-dependent daylength effect. Optimal temperatures occurred between 15 and 20°C. Both the initial slope () and the growth rate at light saturation (μ_max) were strongly influenced by temperature; increased five-fold and μ_max by an order of magnitude between 5 and 20°C. The compensation irradiance (I_c) was independent of temperature. μ_max was 2.7 div day⁻¹ at 20°C, 2.6 at 15°C, 1.1 at 10°C, and 0.3 at 5 °C. Cells grown under 15:9 and 12:12 LD exhibited similar growth-light curves at 20°C and at 15°C. μ_max of cells grown under 9:15 LD at these temperatures were substantially lower than μ_max under longer daylengths. Growth at 10 and 5°C was independent of daylength.

Dark respiration rates were a linear function of cell division rates at 10, 15, and 20°C, and support the concept that growth rate is dependent on dark respiration rate. These relationships were not influenced by daylength. A detectable relationship between dark respiration and growth at 5°C was not observed.

Photosynthesis and excretion showed temperature-dependent curvilinear relationships with growth rate, reflecting the lower saturation irradiance for growth compared to light saturation of photosynthesis and excretion. The relationship between Chl a-specific photosynthesis and growth was controlled by the C:Chl a ratio, which showed a positive correlation with cell division rate. At 15 and 20°C, light saturation of growth was associated with C:Chl a ratios of 40 to 60; at 5 and 10°C, cells growing at μ_max contained C:Chl a in ratios of 80 to 110.     

Long-term regulation of sucrose intake by the female mosquito, Aedes taeniorhynchius

Newly emerged female Aedes taeniorhynchus were maintained in cups provided with potometers containing 5, 10, and 25% sucrose solutions. Mortality and the ab lib. intake of sucrose were recorded daily and groups were sampled at regular intervals for analysis of energy reserves.After a week of relatively substantial intake of sucrose at all three concentrations, a constancy in daily intake at much lower levels was observed during the next 4 weeks. The caloric intake was highest in the 25% sucrose solution group. There were no differences in mortality rates at these concentrations. Glycogen (0·7–1·0 cal/female) and triglycerides (3·5dash4 cal/female) reserves reached maximum levels after the first week and stabilized thereafter on all three concentrations. In this species the stabilization in intake of sucrose solution after the first week is correlated with the maximum accumulation of stored energy reserves as opposed to decreased activity or subtle changes associated with senescence.     

Effects of salinity on survival,daily food intake and growth of juvenile round goby Neogobius melanostomus (Pallas, 1814) from a brackish water system

The growth response of juvenile round gobies was tested in various salinities to assess the potential performance of the species in widely differing salinities in the Baltic Sea and adjacent waters. An experimental approach analysed the survival, daily food intake and growth of juvenile Neogobius melanostomus from the brackish water region of the Kiel Canal, Germany. Round gobies (TL = 61.5 ±5.3 mm; n = 40) were fed ad libitum (diet = mysid shrimp; energy content = 4.7 cal per mg dry weight) at salinity levels of 0.1, 7.5, 15 and 30 over 12 weeks. Two replicate tanks (125 × 30 × 30 cm; 100 L) were maintained for each salinity level, each holding five specimens at a mean temperature of 19.90°C (±0.64°C; n = 136). Survival at all levels was 100%, except for 0.1 with 90%. Mean daily food intake (% of body weight) increased from salinity level 0.1 to 15 (from 17.76% to 19.95%); specimens at level 30 showed a more diversified and lower mean food intake (18.44%). Mean cumulative body weight gain appeared greatest at a level of 7.5 (224.52%), closely followed by 0.1 (206.57%) and 15 (191.92%). In contrast, fish growth was significantly lower at a salinity level of 30 (100.57%). Results of the experiment indicate that salinity tolerance estimates of the round goby made by other authors are too low regarding specimens that stem from brackish habitats. Growth patterns of some specimens, even in the salinity 30 treatment, show that a further spread of this species into regions with higher salinities is quite possible.     

Effects of chronic heat exposure and protein intake on growth performance, nitrogen retention and muscle development in broiler chickens

The respective effects of ambient temperature, dietary crude protein and feed intake were investigated in finishing chickens and the consequence of protein supplementation under high temperature conditions was analysed in particular. Heat-related reduction in growth was associated with decreased nitrogen retention (-30 or -35% according to the diet), which could not be explained by the observed lower feed intake alone. Tissue samples performed in 5- to 6-week-old chicks showed varying effects of heat according to the muscles studied: at 32 degrees C, the proportion of Pectoralis major muscle (in percentage of body weight) appeared slightly reduced (reduction lower than 10%), whereas the proportion of two leg muscles were increased (+10 to +15% for the Sartorius muscle; +5% for the gastrocnemius muscle). At 32 degrees C, providing a high protein diet significantly (P < 0.05) increased weight gain and feed efficiency, and slightly improved whole body protein deposition.     

Cub growth and maternal care in cheetahs

Using cub growth as an index, I examine the influence of maternalnutrition, litter size, and cub sex on maternal care in cheetahs(Acinonyx jubatus) and compare cub and litter growth rates withthose of other large feilds. Seventy-nine free-living cheetahcubs in 21 litters from 15 mothers were weighed at least oncebetween 6 and 48 days of age. Eleven litters were weighed atthe beginning and end of a 5-day observation of their mothers.The mean cub growth rate varied significantly between litters,due primarily to differences in maternal food intake. Growthdeclined sharply when maternal food intake was less than 1.5kg/ day, but did not increase with greater levels of food intake.Lower limits of growth rates may therefore have been set bythe mother's food intake, whereas upper limits may be set bythe intrinsic physiological ability of cubs to grow. Althoughmale cubs were heavier than female cubs in the same litter whenfirst weighed, major differences in growth rate between thesexes were not apparent at this stage. Both cheetah cubs andlitters grow fast relative to other large felids, and I arguethat this may be an adaptation to the high rate of cheetah juvenilemortality from predation.     

Skeletal and heart muscle protein turnover during long-term exposure to high environmental temperatures in young rats

A study was undertaken to determine the long-term effects of a hot environment on protein turnover in skeletal and cardiac muscles of young homeothermic animals. Three groups of 36 male 28 day old rats were housed at 35 degrees C (hot group), 25 degrees C (control group), or 25 degrees C but pair-fed to the intake of the hot group (pair-fed group). Rates of protein synthesis and degradation were measured in vivo on days 5, 10, 15, and 20. By day 20, soleus and gastrocnemius (skeletal muscle) protein masses were 7 and 14% lower in the hot group and 31 and 21% lower in the pair-fed group compared with the control group (P < 0.05). The fractional rate of protein synthesis (k(syn)) was on average 11% lower (P < 0.05) in the hot group compared with control rats and was not different from pair-fed rats. The fractional rate of skeletal muscle protein degradation (k(deg)) in hot rats was slightly lower than in control rats; k(deg) was on average 18% higher (P < 0.05) in the pair-fed group compared with the hot group and this difference appeared to be most prominent on day 5. In heart, by day 20, protein mass was 30% lower in the hot group and 40% lower in the pair-fed group compared with control rats (P < 0.05). k(syn) was on average 19% lower (P < 0.05) in the hot group compared with the control group, but not different from pair-fed rats. In the heart there were no differences in k(deg) among treatments. Plasma triiodothyronine (T3) concentration was lower in the hot group, but not in the pair-fed group, compared with controls. In conclusion, chronic exposure to hot environments was associated with lower skeletal and cardiac muscle mass and protein turnover; lower protein mass in this tissue was due to decreased k(syn); this is consistent with lower plasma T3 concentrations. In pair-fed rats, k(syn) was also reduced, but interestingly k(deg) was not, resulting in a greater loss of skeletal muscle mass. These results suggest that heat exposure invokes physiological adaptations to preserve skeletal muscle mass despite decreased food intake. In the heart, loss of protein was a result of decreased k(syn), which can be primarily ascribed to lower food intake.     

Living on the edge: Dietary strategies of economically impoverished women in Cali,Colombia

Economically impoverished women in Cali, Colombia, have restricted access to food in a city where food is abundant. Ethnographic observations, interviews and 2 day food records were used to better understand the coping strategies used by a group of these women (n = 85) to maintain adequate levels of energy intake. Anthropometric indicators of nutritional status were normal for the group. Interview data revealed that the ability to purchase food was a concern for 58% of the women. When faced with a restricted ability to purchase food, the women indicated they made compromises in meal composition, reduced portion sizes, and/or reduced the number of meals. They also relied on relatives, friends, neighbors, store credit, or local government programs for access to food. Changes in meal composition were identified in 17.1% of all diet records (n = 509). Low energy intake (defined as energy intake ≤ 1.27 × BMR) was identified in 17.1% of all diet records. Carbohydrate consumption was significantly greater on low-energy intake days. The adequate nutritional status of this group of women suggests that their coping strategies are usually adequate to maintain energy intake, but the presence of uncertainty, the frequency of compromises in diet composition, and the frequency of low-energy intake days suggest that these women are at risk for undernutrition. Am J Phys Anthropol 102:5–15, 1997. © 1997 Wiley-Liss, Inc.     

Effects of temperature, irradiance, and daylength on the marine diatom Leptocylindrus danicus Cleve. III. Dark respiration

Oxygen consumption in the dark by the marine diatom Leptocylindrus danicus Cleve was measured in batch culture under 49 combinations of temperature (5, 10, 15, 20°C), daylength (15:9, 12:12, 9:15 LD), and irradiance (at least four irradiances per daylength). Dark respiration was influenced by previous light history and temperature. Elevated respiration rates characterized cells grown under higher irradiances at 10, 15, and 20°C; the effects of previous light history were more evident at higher temperatures. At 5°C, oxygen consumption was unaffected by growth irradiance. The highest respiration rates were measured at 20°C; the Q₁₀ value for dark respiration (5 to 20°C) was 4.0. Daylength affected oxygen consumption at 15 and 20°C. The mean R:P ratio in all experiments was 0.139, with lower ratios at higher temperatures and irradiances, and higher ratios at lower temperatures and irradiances. The R:P ratio was unaffected by daylength. Carbon-specific respiration rates exceeded excretion losses in all experiments except under high irradiances at 5°C. The E:R ratio was smaller at lower irradiances and higher temperatures; daylength effects were not evident.