Effect of nutrition on the excretion rate of soluble nitrogenous products of Luidia clathrata (say) (Echinodermata; Asteroidea)

• 1.1. Groups of Luidia clathrata were fed maintenance level diets of Donax variabilis (50% protein by dry weight) or Penaeus duorarum (80% protein) or were starved.
• 2.2. The NH₄⁺ excretion rates for all treatments increased from 6.06 ± 2.55 to 14.39 ± 4.31 μg NH₄⁺ − N/g dry wt per hr after 20 days.
• 3.3. The urea excretion rate for all treatments was 1.25 ± 3.39 μg urea-N/g dry wt per hr for 56 days.
• 4.4. The pyloric caecum index (percentage of wet body weight) decreased 16.5 and 73.4%, for Donax variabilis-fed and starved sea stars, respectively. The pyloric caecum index of Penaeus duorarum-fed sea stars increased 81.5%. The protein level of the pyloric caeca was 47.00 ± 4.14% of the dry weight for the fed animals and 37% for the starved animals.
• 5.5. Increased NH₄⁺ excretion rates with starvation or presumed maintenance diets appear to be due to tissue catabolism.

     

Increased muscle glucose uptake in response to chronic glyburide treatment is not related to changes in glucose transporter (GLUT4) protein

• 1.1. The mechanism of action of glyburide (a sulfonylurea) on muscle has been investigated by measuring glucose uptake and glucose transporter (GLUT4) protein levels after chronic glyburide treatment.
• 2.2. A dietary induced insulin resistant rat model (4 wk of high-fat, high-sucrose feeding) was given glyburide (2mg/kg/day) for 10 days and glucose uptake was measured in a perfused hindquarter preparation.
• 3.3. Protein levels of the GLUT4 glucose transporter were determined by Western analysis.
• 4.4. After 7 days of treatment, rats fed glyburide had lower blood glucose concentrations 2 hr (72 ± 5 vs 103 ± 12 mg/dl) and 24 hr (97 ± 7 vs 123 ± 7 mg/dl) after glyburide administration with no difference in serum insulin levels compared to vehicle treated animals.
• 5.5. Glucose uptake was approx doubled in basal state (0 insulin) in response to glyburide (2.8 + 0.4 vs 1.7 ± 0.2μ mol/g per hr).
• 6.6. Maximal insulin (100 nM) stimulated glucose uptake tended to be higher in the glyburide treated group, but did not reach statistical significance (8.0 ± 0.7 vs 7.0 ± 0.6 μmol/g per hr).
• 7.7. Western analysis revealed no significant effect of glyburide on the GLUT4 protein level in skeletal muscle.
• 8.8. These results suggest that glyburide alters glucose uptake through some mechanism other than alterations in the level of the GLUT4 glucose transporter protein.

     

Oxygen uptake in larval bollworms (Heliothis zea) infected with the fungus Nomuraea rileyi

• 1.1. Healthy 6- to 12-day-old Heliothis zea (bollworm) larvae showed a mean oxygen uptake of 3.1 μl O₂/mg body wt per hr.
• 2.2. Similar larvae infected with the fungus Nomuraea rileyi had a mean uptake of 4.01 μl O₂/mg per hr.
• 3.3. The weights of the two groups of insects did not differ.
• 4.4. T-test showed a significant (P < 0.01) difference in oxygen uptake between healthy and infected larvae.

     

Glucose metabolism in a kangaroo (Macropus robustus erubescens) and a similar size eutherian herbivore,the feral goat

• 1.1. Glucose pool size, space, entry rate, and turnover time were estimated from the specific radioactivity vs time curves of [³H] and [¹⁴C]glucose administered as a single injection in the euro (Macropus robustus erubescens) and the sympatric feral goat (Capra hircus).
• 2.2. Digestible energy intake was greater (P < 0.05 ± SE) in the goat than in the euro (798 ± 64 vs 624 ± 31kJ/kg^0.75 × day).
• 3.3. However, there were no significant differences between the two species in parameters of glucose metabolism.
• 4.4. The use of an implantable osmotic infusion pump to deliver isotopic glucose showed promise as a means of avoiding the stress involved with the single injection technique.

     

The flow theory of enzyme kinetics: Role of solid geometry in the control of reaction velocity in live animals

• 1.1. When blood flows, membranes are bombarded with ions etc., whose entry creates an ATP demand proportional to flow rate. Also proportional to flow rate is ATP production from oxidation of substrates [S] from the same blood volume.
• 2.2. O₂ is limiting and reaction velocity at rest (metabolic rate) is determined by flow rate, F, but not by [S].
• 3.3. Since resting blood O₂ A-V difference is about 5 vol%, 11 circulated produces about 0.25 kcal in mammals, birds or warm reptiles.
• 4.4. Where O₂ is not limiting, as in most amino acid deaminations, V = K F[S] with K a constant unrelated to K_m.
• 5.5. At equal blood vol/kg, solid geometry dictates that the average cross-sectional area of major vessels/kg will be an inverse function of body mass. The smaller the animal, the shorter the vessels, the “thicker” the vessels/kg body wt, and at any one blood pressure, the higher the flow/kg/hr. If a man's major vessels were equal in cross-section/kg to those of a shrew, it would take 2241 of blood to fill them.
• 6.6. Growth decreases flow/kg (and therefore metabolic rate), by decreasing vessel cross-section/kg without changing blood pressure or linear velocity of flow.
• 7.7. Surface area/g, body wt to some power, average vessel length/kg, circulation time and average major vessel cross-sectional area are all related mathematically.

     

Aerobic glucose disposal in the oyster: An in vivo kinetic analysis

• 1.1. Aerobic glucose disposal in starved oysters exposed to 1 mM external glucose was 2.29 μg C/g wet wt/min.
• 2.2. It was hypothesized that the maximum disposal rate is limited by the maximum rate of transepithelial glucose transport.
• 3.3. The major recipients of glucose-carbon were glycogen and amino acids. 4. The rate of glucose-carbon disposal to these two pools was 0.80 and 0.42 μg C/g/min, respectively.
• 4.5. The internal energy state determines the pathways of glucose disposal.
• 5.6. Disposal of glucose-carbon in “glucose-primed” oysters is primarily into glycogen.
• 6.7. In fasted bivalves the disposal is primarily into amino acids and carboxylic acids.
• 7.8. The uptake of dissolved glucose has the potential of contributing significantly to growth under conditions where the external glucose concentration is kept artificially high.

     

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.

     

Carcass proximate composition of juvenile white sturgeon (acipenser transmontanus)

• 1.1. Body wt, carcass wt, liver wt, gonad wt, total length, and carcass proximate compositions of 8- to 32-month-old cultured sturgeon were significantly affected (P < 0.05) by ages.
• 2.2. Correlation coefficients were significant between age and body wt (r = 0.96), carcass wt (r = 0.96), total length (r = 0.92), liver wt (r = 0.88), gonad wt (r = 0.76), gonadosomatic index (r = 0.52), carcass moisture (r = −0.93), crude protein (r = 0.62) and lipid (r = 0.57).
• 3.3. The carcass proximate compositions of cultured sturgeon were 72.1–79.4% moisture, 13.5–17.5% crude protein, 3.4–7.4% crude lipid, and 4.2–5.0% ash.
• 4.4. A high variability in the body measurements and carcass proximate compositions of some cultured sturgeon suggested high potential for genetic and nutrition improvements in culturing these fish in hatcheries.

     

Effects of dietary estradiol-17β on feminization,growth and body composition in the Japanese eel (Anguilla japonica)

• 1.1.Juvenile Japanese eels (Anguilla japonica) were fed on a diet supplemented with estradiol-17β (E₂) at doses of 25, 50 and 75 mg/kg. The effects on growth, sex distribution and body composition were investigated in two groups of gonadally undifferentiated stages (early and later juvenile stages).
• 2.2.Feminization (95–100%) was observed in all E₂-treated groups.
• 3.3.The growth rate of fish treated with 25 and 50 mg/kg E₂ diet at the early juvenile stage was significantly increased.
• 4.4.The amount of protein in muscle decreased and that of fat increased in the E₂-treated groups except in the early juvenile stage fed with 25 mg/kg E₂.

     

Responses of channel catfish (Ictalurus punctatus) swim-up fry to dietary calcium in soft and hard water

• 1.1. Responses of channel catfish (Ictalurus punctatus) swim-up fry to dietary calcium in soft (< 1 mg/1 as CaCO₃) and hard (> 100 mg/1 as CaCO₃) water were determined by feeding purified egg-white diets containing 0, 0.5, 1.0, or 2.0% calcium from CaCO₃ for 8 weeks.
• 2.2. Catfish fry fed the basal diet (0.03% Ca) in hard and soft water had lower whole-body ash and whole-body calcium concentrations but higher weight gain and survival than those fed calcium-supplemented diets.
• 3.3. Fry in soft water generally had lower whole-body ash, whole-body calcium, and survival, as well as a higher incidence of spinal deformities than fry in hard water.
• 4.4. Feeding higher levels of calcium to fry reared in soft water did not increase whole-body calcium levels or decrease spinal deformities to the levels observed for fry reared in hard water and fed supplemental calcium.
• 5.5. These data indicate that calcium derived solely from dietary or environmental sources was not sufficient for optimum health of channel catfish fry.

     

Factors regulating the functioning of the in vitro perfused aglomerular kidney of the anglerfish,Lophius piscatorius L.

• 1.1. Kidneys of Lophius were perfused from the renal portal vein with a Ringer's solution.
• 2.2. Mammalian and piscine neurohypophysial hormones (in doses of 20–500 ng/kg body wt) did not affect the rate of urine production or the urinary concentration of inorganic ions.
• 3.3. The rate of urine production and the urinary concentration of magnesium and sodium ions varied with the concentration of magnesium in the perfusate.
• 4.4. The rate of urine production was positively correlated with urine magnesium concentration (r = 0.83 ± 0.04) and negatively correlated with that of sodium (r = −0.40).
• 5.5. The urinary concentration of sodium ions varied inversely with that of magnesium ions (r = −0.89).
• 6.6. Ouabain treatment (0.1–0.8 mM/l) reduced the rate of urine production by over 60% and altered, to varying extents, the pattern of electrolyte excretion. A simple model for the mode of formation of urine by the aglomerular kidney, based on the present results and other observations is suggested.

     

Combined effect of adenosine,alpha adrenergic and adenosine antagonists on serum insulin and insulin secretion from rat pancreatic islets

• 1.1. The effect of adenosine separately or in combination with alpha-1 adrenergic antagonist prazosin and alpha-2 adrenergic antagonist yohimbine as well as adenosine antagonists 8-phenyltheophylline and xanthine amine conjugate on glucose-induced insulin secretion from isolated rat pancreatic islets was studied.
• 2.2. Their in vivo effects on serum glucose and insulin levels were also investigated. Adenosine at 10 and 100 μM inhibited significantly, insulin secretion from the isolated islets whereas at 10 mM slightly increased the secretion of insulin.
• 3.3. Prazosin used at 100 μM inhibited insulin secretion. When it combined with adenosine (10 μM) it augmented the inhibitory effect of adenosine.
• 4.4. In vivo prazosin (21 mg/kg bodywt) caused a hyperglycaemia which was accompanied by hypoinsulinaemia.
• 5.5. Concurrent administration of this drug with adenosine neither affect the hyperglycaemic nor the hypoinsulinaemic effects of adenosine.
• 6.6. On the other hand, yohimbine (100 μM) has no effect neither separately nor in combination with adenosine (10 μM) in modulating the inhibitory effect of adenosine on insulin secretion.
• 7.7. When Yohimbine administered at 19.5 mg/kg body wt it did not alter serum glucose but it markedly increased the serum insulin level. Its combined administration with adenosine reduced the hyperglycaemic effect of adenosine with a remarkable increase in serum insulin.
• 8.8. Both adenosine-antagonists were ineffective in alteration of insulin secretion.
• 9.9. However, combination of 8-phenyltheophylline with adenosine (10 μM) totally blocked the inhibitory effect of adenosine on insulin secretion while xanthine amine conjugate failed to prevent this effect of adenosine.
• 10.10. These results indicate that the inhibitory effect of adenosine on insulin secretion is neither mediated via alpha-1 nor alpha-2 adrenoceptors. It might be via activation of specific adenosine receptors on rat islets which are sensitive to blockade by 8-phenyltheophylline.

     

Effects of high dietary methionine on activities of selected enzymes in the liver of kittens (felis domesticus)

• 1.1. Growing male kittens were fed an 18% casein diet supplemented with 2, 3, or 4% l-methionine (MET) for 6 weeks.
• 2.2. Free MET concentration in liver increased 30-fold and cystathionine two- to three-fold; the activity of adenosyl-MET transferase and cystathionase also increased but remained lower than previously found in rats.
• 3.3. Taurine concentration in liver decreased in cats fed excess MET and appeared to depend on taurine intake.
• 4.4. Alanine aminotransferase activity was high in all groups while serine dehydratase activity was very low.
• 5.5. Pyruvate kinase and malic enzyme activities which are normally low in cat liver increased after excess MET. Also, glucose 6-phosphate and 6-phosphogluconate dehydrogenases increased.
• 6.6. Cat liver metabolism showed limited adaptation to an excess dietary intake of methionine compared to that found in rats.

     

The effect of cortisol on stimulation of enzymatic activity and absorption of amino acids in the small intestine of adult hamsters

• 1.1. The s.c. administration of cortisol to hamsters (50 mg/kg body wt/day for 4 days) produces a significant increase in maltase sucrase, alkaline phosphatase and leucineaminopeptidase activity in intestinal mucosa.
• 2.2. Lactase activity is unaffected by cortisol.
• 3.3. Gamma-glutamyltranspeptidase activity increases slightly in females but remains unchanged in males.
• 4.4. Cortisol causes increase in proline and glycine absorption without changing the absorption of lysine.

     

The peculiarities of nitrogen excretion in sturgeons (Acipenser ruthenus) (Pisces,Acipenseridae)—I. the influence of ration size

• 1.1. The nonfaecal nitrogenous excretion rate in starved sterlet fingerlings and fingerlings fed on different rations was investigated. The weight of the fish and temperature of the water was 43 g and 17.5°C, respectively.
• 2.2. In the nonfaecal excrements of starved sterlets the ammonia: urea ratio was substantially lower than in teleosts. This ratio was found to be 1.4:1.
• 3.3. In fed sterlets the urea excretion rate was higher than in starved ones but independent of ration size.
• 4.4. During the day the urea excretion rate in sterlets was constant.
• 5.5. The ammonia excretion rate accelerated 2 hr after feeding and reached its peak duration 6–11 hr after depending on the ration size.
• 6.6. Total ammonia output in the sterlet increased following the increase of ration size up to 8.4% of body wt. Further increases in ration size did not cause the corresponding elevation of ammonia excretion rate.

     

The biochemical and energetic composition of somatic body components of echinoderms from the northern Gulf of Mexico

• 1.1. The biochemical and energetic compositions of the somatic body components of seven species of asteroids, one ophiuroid, and four echinoids from the northern Gulf of Mexico (30–95 m depth) were ascertained.
• 2.2. Levels of ash were high (68.5–90.8% dry wt) in all body-wall tissues, with the exception of the asteroid Echinaster modestus (51.6% dry wt). Levels of ash were low in the pyloric cecae (nutrient storage organ) of asteroids (4.6–30.8% dry wt).
• 3.3. Levels of lipid (8.1–34.5% dry wt), soluble protein (15.9–28.7% dry wt), and insoluble protein (18.1–48.6%, dry wt) were high in the pyloric cecae of all asteroids, but generally low in ophiuroid and echinoid body-wall tissues. High protein levels (28.5–44.5% dry wt) in the body-wall of the asteroids Echinaster modestus and Anthenoides pierceisuggest it may play a role in nutrient storage.
• 4.4. All somatic tissues contained low levels of carbohydrate (0.2–1.4% dry wt).
• 5.5. Levels of energy in pyloric cecal tissues (12.99–26.05 kJ/g dry wt) were 4–8 times higher than in echinoderm body-wall tissues (2.92–11.91 kJ/g dry wt).
• 6.6. The biochemical and energetic compositions of echinoderms from the northern Gulf of Mexico are similar to those of species from other latitudes and depths.

     

Hemolymph ferritin and radula structure in the limpets Patelloida alticostata and Patella peronii (Mollusca: Gastropoda)

• 1.1. The mean concentration of total hemolymph iron was 3060μg/100 ml in Patella peronii and 2950μg/100 ml in Patelloida alticostata.
• 2.2. Ferritin was found to act as a major iron-binding protein in the hemolymph of both P. peronii and P. alticostata.
• 3.3. P. alticostata ferritin has a molecular weight of approximately 505,000, while that of P. peronii has a mol wt. of approximately 520,000.
• 4.4. The lateral radula teeth of both species are mineralized by deposits of silica (SiO₂) and iron in the form of goethite (α-FeOOH).
• 5.5. Hemolymph ferritin is suggested to act as a high capacity transport system to supply iron to the mineralizing front of the radula.

     

Glucose turnover in fasted cynomolgus monkeys (Macaca fascicularis) as measured by (2-3H), (6-3H) and (U-14C) glucose

• 1.1. Mixtures of (2-³H) and (U-¹⁴C) or (6-³H) and (U-¹⁴C) glucose were injected as single doses into fasted Cynomolgus monkeys to obtain rates of glucose utilization, percentage of ¹⁴C recycling, percentage of glucose #/rarr2; fructose-6-phosphate substrate cycling, mean transit time and total body mass of glucose.
• 2.2. Rates of utilization were estimated to average 4.9, 4.0 and 3.0 mg/min per kg body weight with (2-³H), (6-³H) and (U-¹⁴C) glucose as tracers, respectively.
• 3.3. Heuristic evidence is presented to show that an anomaly in mean transit time is related to discrimination against the (2-³H) isotope.
• 4.4. The rates of glucose utilization obtained for monkeys are similar to those reported for other mammalian species: however, they are markedly less than values reported for the chicken and considerably greater than those reported for fish.

     

The carotenoids of eggs of wild and farmed cod (Gadus morhua)

• 1.1. Eggs of wild cod, and of farmed cod fed (a) a diet supplemented with astaxanthin and (b) a diet supplemented with both astaxanthin and canthaxanthin, were analysed with respect to carotenoids.
• 2.2. The total carotenoid contents in eggs were 0.7 ppm for wild cod and 0.5 ppm for farmed cod.
• 3.3. Cod, having white flesh, deposit ketocarotenoids in the eggs, preferably astaxanthin.
• 4.4. Canthaxanthin can replace astaxanthin in the eggs, but astaxanthin appears to be deposited preferentially when both carotenoids are present in the diet.
• 5.5. The isomer distribution of (3S, 3′S):(3R, 3′S, meso):(3R, 3′R) astaxanthin in the eggs reflected the isomer composition of the diet.
• 6.6. Echinenone, 4′-hydroxyechinenone, adonixanthin and zeaxanthin encountered in cod eggs may represent reductive metabolites of canthaxanthin and astaxanthin.

     

Some hematological data from marsh harriers (Circus aeruginosus) in central spain

• 1.1. Hematocrit, total protein and glucose values were determined in blood samples from 19 marsh harriers (Circus aeruginosus), 10 males and nine females.
• 2.2. The different parameters were studied on the basis of the ranges described in other birds.
• 3.3. There was a significant correlation between weight and blood glucose level.