Food deprivation induces differential changes in contents and microstructures of digestive tract and appendages in bluegill fish,Lepomis macrochirus

• 1.1. The digestive tract was compared with the tract appendages (caeca) in bluegill fish, Lepomis macrochirus in their response to short and long term food deprivation.
• 2.2. Fasting for 7 days resulted in 80% reduction of food content in the main tract, but only 40% reduction in appendages (caeca).
• 3.3. The intestine exhibited two different patterns of food distribution under fed and food deprived conditions.
• 4.4. The histopathological impact of starvation was more prominent on the intestine than on caeca.
• 5.5. These results suggest that digestive tract and appendages concommitantly conserve food during food scarcity, but appendages may offer advantages in retaining food longer, and in their greater resistance to starvation-induced effects.

     

Variations of respiratory rate of Tisbe holothuriae humes (copepoda,harpacticoida) in relation to temperature,salinity and food type

• 1.1. The influence of temperature (14,19, 24°C), salinity (26,32, 38,44%.) and food type (artificial diets: Fryfood, Mytilus, Soya, Yeast, Spirulina) on the respiratory rate of Tisbe holothuriae has been studied.
• 2.2. Oxygen consumption decreased with decreasing temperature, but with a greater rate at supra- or subnormal salinities.
• 3.3. Multiple-regression analysis showed the quadratic effect of temperature and the linear effect of salinity to be the more important factors affecting respiration.
• 4.4. The food type also seems to exert an important effect on oxygen consumption.
• 5.5. A significant lowering of respiration was observed for all food tested when the animals were starved.

     

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Effects of dietary T-2 toxin concentrations fed to larvae of the yellow mealworm at three dietary protein levels

• 1.1. Growth, but not survival, of larvae of Tenebrio molitor was influenced by concentration of dietary protein, by concentration of T-2 toxin and by interaction of the two.
• 2.2. T-2 toxin reduced the quantities of food and protein used by the larvae and, consequently, gain in larval weight.
• 3.3. Efficiency of food conversion was constant, but efficiency of protein conversion was influenced by dietary protein and dietary mycotoxin concentration.
• 4.4. Concentrations of T-2 toxin of 64 and 128 ppm depressed growth of test larvae significantly, but these levels exceeded the biologically active levels in vertebrates.
• 5.5. A new technique for determining food utilization by insect larvae is described.

     

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Specific dynamic action (SDA) in the supralittoral isopod,Ligia pallasii: Identification of components of apparent SDA and effects of dietary amino acid quality and content on SDA

• 1.1. Specific Dynamic Action (SDA) effects of diet were investigated in the supralittoral isopod, Ligia pallasii, using defined chemical diets.
• 2.2. “Apparent SDA”, or the total rise in metabolic rate following a meal, was resolved in animals eating a nutritionally complete chemical diet into three components: 8% mechanical costs of moving food through the gut, 40% “excitement costs” due to investigator disturbance and presence of food, and 52% SDA.
• 3.3. Excitement costs in animals exposed to food but which chose not to eat showed non-significant variation between diets containing different levels of chemical nutrients, but were significantly less on a diet containing only cellulose and agar.
• 4.4. SDA increased with increasing concentration of amino acids in the diet.
• 5.5. Substitution of whole-protein casein for free amino acids in the diet had no significant SDA effect, while substitution of free amino acids in the ratio found in casein more than doubled the SDA effect.
• 6.6. Deletion of alanine from the diet caused no significant effect on SDA, while deletion of phenylalanine caused a highly significant elevation in SDA.

     

Elementary chemical composition of Tisbe holothuriae humes (copepoda: harpacticoida) as influenced by temperature,salinity and food type

• 1.1. The copepod Tisbe holothuriae was collected from the Saronicos gulf of Greece and cultured in the laboratory, under dif'erent combinations of temperature and salinity and as well as different types of food.
• 2.2. The content of C, H and N in females was measured.
• 3.3. As temperature increases and salinity declines from 38%, the content of C, H and N per individual decreases.
• 4.4. The type of food influences the carbon and hydrogen content per individual, while the nitrogen content is relatively constant.
• 5.5. The percentage content of C, H and N in females without egg sacs and females carrying their first newly formed egg sacs do not differ significantly

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Determination of benzo(a)pyrene in isopods (Porcellio scaber Latr.) exposed to contaminated food

• 1.1. A method is presented for the determination of the polycyclic aromatic hydrocarbon benzo(a)pyrene (BaP) in the isopod Porcellio scaber, using reversed-phase HPLC with fluorescence detection.
• 2.2. This technique has a detection limit for BaP in P. scaber of approximately 3.2 ng g⁻¹ fresh weight.
• 3.3. BaP was assimilated from food by P. scaber.
• 4.4. After four weeks of ad libitum feeding on BaP-contaminated food, concentrations in the isopods were approximately 30–40 times lower than those in the food.
• 5.5. Male and female isopods did not differ in BaP concentration. Variation among males seemed to be much higher than among females.

     

Breast,hips, and buttocks revisited: Honest fatness for honest fitness

This paper comments on: Low, B. S., Alexander, R. D., and Noonan, K.M. Human hips, breast, and buttocks: Is fat deceptive? Ethology and Sociobiology 8: 249-247, 1987. In it I argue that:

• 1.1. Sexual selection has probably not been the most important selection pressure on
• 2.female human body shape.
• 3.2. Male humans in different cultures find different aspects of the female body attractive
• 4.and therefore are unlikely to have exerted consistent directional sexual selection on
• 5.the female body.
• 6.3. Breast size is not correlated with lactation success.
• 7.4. Visible hip width is not correlated with parturition success.
• 8.5. Women would lower their fitness if they tried to deceive men about their internal
• 9.pelvic dimensions.
• 10.6. There are many alternative hypothesis to explain the existence of fat onwomen's
• 11.breast, hips, and buttocks.

     

Purification and characterization of hatching enzyme of the pike (Esox lucius)

• 1.1. A choriolytic enzyme was isolated from the hatching medium of the pike, Esox lucius.
• 2.2. The enzyme is defined as hatching enzyme.
• 3.3. The molecular weight of the enzyme is 24,000.
• 4.4. The enzyme is a glycoprotein containing 2% carbohydrate.
• 5.5. Its isoelectric point is 6.5.
• 6.6. The pH optimum is around pH 8.
• 7.7. The enzyme molecule contains two disulfide bonds but no free cysteine.
• 8.8. Inhibitor studies and metal analysis show that the enzyme is a zinc-metalloprotease.

     

Cross-correlation analysis of cerebrobuccal connective activity during Aplysia feeding behaviour

• 1.1. Two “en passant” electrodes were implanted around the cerebrobuecal connective (CBC) of Aplysia and used to record the activity, in the unrestrained animal, under three behavioural conditions; (a) absence of feeding behaviour, (b) appetitive feeding behaviour and (c) consummatory feeding behaviour.
• 2.2. The two simultaneous recordings were subjected to cross-correlation analysis, to subdivide spikes on the basis of their direction and speed of propagation.
• 3.3. There was virtually no CBC activity in the absence of food and feeding behaviour.
• 4.4. During appetitive feeding the metacerebral giant cell (MCC) was active and traffic was heaviest in the cerebral-to-buccal direction.
• 5.5. During consummatory feeding, traffic was also sustained in the buccal-to-cerebral direction; there was a reduction in the activity of the MCC, and a peak in the activity travelling to the cerebral ganglia, in the region of higher conduction velocity, was especially pronounced.
• 6.6. Further analysis showed this peak to have its largest amplitude during the actual ingestion of food and to be the result of the firing of several different units.
• 7.7. CBC traffic in both directions was also activated in one case of “spontaneous” biting.

     

Cloning and characterization of rabbit pancreatic colipase

• 1.1. Among the digestive enzymes synthesized by pancreas, lipase is the principle lipolytic enzyme which hydrolyses dietary glycerides.
• 2.2. For its action it requires a coenzyme, colipase.
• 3.3. The molecular mechanisms of the interaction of these two are not fully understood.
• 4.4. Further, molecular events that regulate and influence lipid absorption are ill denned.
• 5.5. The rabbit is the conventional animal model for the study of lipid absorption. We have undertaken the molecular cloning, and characterization of rabbit pancreatic colipase, the coenzyme for pancreatic lipase.
• 6.6. Colipase has been cloned from a gt 11 library of an adult rabbit pancreatic cDNA by probing with an oligonucleotide derived from human colipase sequence.
• 7.7. The total reading frame consists of 321 nucleotides coding for 90 amino acids of the functional protein and 17 nucleotides of the leader peptide.
• 8.8. Northern blot analysis revealed a distinct band around 0.5kb. Comparison with other species revealed an over all homology of 75% at the nucleotide level.
• 9.9. At the amino acid level highest conservation is observed at the lipase-binding region (AA 53–73).
• 10.10. Rabbit enzyme also retained the N-terminal pentapeptide of it preform.
• 11.11. The regions of homology and conservation may aid to define the sites of interaction of colipase with lipase.

     

Effects of temperature and food on the free amino acids in tissues of roach (Rutilus rutilus L.) and rudd (Scardinius erythrophthalmus L.)

• 1.1. In liver and muscle the concentrations of free amino acids (FAA) are highest in fish maintained at low temperature and fed mealworms. These effects are more pronounced in roach than in rudd.
• 2.2. In the liver alanine, glycine and glutamate are the dominant FAA but proline increases in mealworm-fed animals.
• 3.3. In muscle, histidine and glycine dominate, except that a mealworm diet leads to an increase in the concentration of proline and to a concomitant decrease in the concentration of glycine.
• 4.4. Starvation leads to a reduction of total FAA content but to relative increases of lysine and histidine. These two FAA can serve as indicators of the general state of nutrition of roach and rudd.
• 5.5. The molar ratio [gly]/[his] is strongly correlated with temperature, decreasing with an increase in the temperature to which the animals had been exposed prior to capture.
• 6.6. The patterns of free and bound amino acids diverge more widely in these species than in mammals which reflects the greater dependence of the FAA pools of fish on intrinsic and extrinsic factors.
• 7.7. The concentrations of histidine in the FAA pools of muscle and in food proteins are strongly correlated.

     

Structural and functional effects of heavy metals on the nervous system,including sense organs,of fish

• 1.1. Today, fish in the environment are inevitably exposed to chemical pollution. Although most hazardous substances are present at concentrations far below the lethal level, they may still cause serious damage to the life processes of these animals.
• 2.2. Fish depend on an intact nervous system, including their sense organs, for mediating relevant behaviour such as food search, predator recognition, communication and orientation.
• 3.3. Unfortunately, the nervous system is most vulnerable and injuries to its elements may dramatically change the behaviour and consequently the survival of fish.
• 4.4. Heavy metals are well known pollutants in the aquatic environment. Their interaction with relevant chemical stimuli may interfere with the communication between fish and environment.
• 5.5. The affinity for a number of ligands and macromolecules makes heavy metals most potent neurotoxins.
• 6.6. The present Mini-Review highlights some aspects of how trace concentrations of mercury, copper and lead affect the integrity of the fish nervous system; structurally, physiologically and biochemically.

     

Influence of temperature,rate of feeding and body weight on nitrogen metabolism of bream,Abramis brama L

• 1.1. Measurements of the rate of nitrogen consumption, total nitrogen and ammonia excretion and nitrogen absorption of bream, Abramis brama L. (body weight range 0.4–519 g wet wt) were made at 10, 15 and 20 C.
• 2.2. Fish were fed once daily on live zooplankton collected in Lake Balaton and cultured Tubifex sp. at 5–15% of their body weight.
• 3.3. Fish size and temperature had a combined effect on the rate of total nitrogen excretion. Total nitrogen excretion did not increase proportionally with an increase in consumption.
• 4.4. On average, 52–80% of the nitrogen consumed with food was excreted by bream.
• 5.5. The greatest part of total nitrogen excretion was ammonia and its proportion in the total ranged between 53 and 75%.
• 6.6. Temperature did not have any significant effect on the proportion of excreted ammonia and the rate of excreted total nitrogen was the only factor determining its proportion in the total.
• 7.7. The rate of nitrogen absorption of bream was surprisingly very high.

     

Effects on growth and respiration due to the ingestion of the rapeseed meal glucosinolates in young larvae of Tenebrio molitor

• 1.1. We investigated the effects of the ingestion of naturally occurring glucosinolates in rapeseed meal on growth rate, metabolic efficiency and respiratory rate in larvae of the yellow mealworm, Tenebrio molitor L.
• 2.2. In our feeding studies, larvae were reared on one of seven different diets, including a whole ground wheat control diet and rapeseed meal from six rapeseed varieties. Dry weight gain of larvae and dry food assimilated were measured after 4 weeks of rearing, and the conversion of food into insect biomass was determined. The results may be explained by variations in the glucosinolates content of the diets.
• 3.3. The effect of glucosinolates on food consumption, larval growth, expired carbon dioxide, oxygen uptake and respiratory quotient were studied.
• 4.4. Glucosinolates did not reduce food assimilation or growth after 1 day of experimentation, but they caused some inhibition of respiratory exchanges and increased the RQ ratio.

     

Seasonal changes of lipids and fatty acids in oyster tissues (Crassostrea virginica) and estuarine particulate matter

• 1.1. Lipid concentration in adductor muscle ranged from 2–68, in visceral mass from 5–28, in mantle and gill from 5–20 and in heart from 27.8–79 mg/g wet tissue. Particulate matter lipids varied from 1.0–2.6 mg/1 of estuarine water.
• 2.2. Neutral and polar lipids ranged from 25–38% of the total lipids in the oyster tissue and from 62–75% of the estuarine particulate organic matter.
• 3.3. Seasonal maxima of lipid concentrations varied among oyster tissues. Peak particulate lipids occurred in November.
• 4.4. It is proposed that seasonal variation in oyster lipids was more related to reproductive cycles than to food lipid supply.

     

Chemical feeding stimulants for the herbivorous fish,Tilapia zillii

• 1.1. Chemical feeding stimulants for an herbivorous fish, Tilapia zillii have been determined by fractionation and bioassay of substances derived from a model food plant.
• 2.2. Stimulation was produced by amino acids; glutamic acid, aspartic acid, serine, lysine and alanine produced the bulk of stimulatory activity.
• 3.3. These amino acids are among the most abundant in the test plant, and are markedly different from the amino acids found to stimulate feeding in carnivorous fish.
• 4.4. On the basis of these results, a chemically-mediated mechanism of feeding niche separation is postulated.