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Biomedical subjects

P Luquet

Publications and source records attributed to P Luquet.

16 recordsLinked to original sources
PubMed1984

Growth reduction in trout induced by naphthenic and isoprenoid hydrocarbons (Dodecylcyclohexane and pristane).

Rainbow trout were fed a diet containing 1% dodecylcyclohexane or pristane for 9 weeks. Feed intake was recorded daily and weight gain every 3 weeks. These animals were compared with fish receiving a hydrocarbon-free diet (groups fed ad libitum and pair-fed groups for which the ration provided was the amount of food consumed by the hydrocarbon-contaminated fish, the day before). The total food ingested by the pristane and dodecylcyclohexane groups amounted to 66 and 70%, respectively, of that eaten by the controls. The final mean weight of the controls was twofold their initial weight. The average weight gain of the dodecylcyclohexane and pristane groups was 37 and 25%. During the same period the fish of the pair-fed groups gained approximately 70% of their initial weight. Significant effects of hydrocarbon consumption on food conversion factors, viscerosomatic index, hepatosomatic index, and liver lipid concentration were observed. The results are discussed in relation to the possible causes of such changes.

Animals↗
PubMed1983

Utilization of dietary urea in rainbow trout.

Experiments were conducted to examine the potential utilization of dietary urea by rainbow trout. A control diet and two diets supplemented with 1 and 3% of urea were fed to fish. Postprandial levels of urea and ammonia in blood plasma, and postprandial excretion of these metabolites were followed during 24 h. Apparent digestibility of urea in rainbow trout was very high (greater than 98%). Maximum values of urea levels in plasma were reached 6 h (32.3 +/- 10.2 micrograms/ml) after a meal in the control fish and respectively 6 h (83.4 +/- 18.4 micrograms/ml) and 8 h (250.3 +/- 96.1 micrograms/ml) after a meal in trout fed 1 and 3% urea diets. Peaks of urea excretion rates appeared 7-9 h after meal, coinciding with the highest circulating urea concentration. Total daily urea excretion amounted to 5.53, 10.43 and 33.80 mg urea N/100 mg N intake in trout fed the control, 1 and 3% urea diets, respectively. It is concluded that the dietary urea is readily absorbed in the digestive tract of trout but is totally excreted thus leading to no beneficial effect on nitrogen balance. This excretion of urea also takes place passively without any increase in energy demands.

Ammonia↗
PubMed1982

[Influence of an elevation of the temperature of water on the digestibility of dry matter, nitrogen and energy of food distributed to the rainbow trout (Salmo gairdneri Rich)].

Rainbow trout adapted to a water temperature of 10 degrees C were subjected to an abrupt rise in temperature (from 10 to 18 degrees C) in a 24-h period. Fish maintained in recirculated water were fed to satiation twice a day and their feed intakes were recorded. Changes in dry matter, nitrogen and energy digestibility were measured each day at 10 degrees C and during the course of acclimatation to 18 degrees C. Low water temperature (10 degrees C) was characterized by a feed intake of 1.84 g (DM)/fish/day; digestibility values were as follows: dry matter 62.15 p. 100, nitrogen 86.91 p. 100, energy 70.60 p. 100. High water temperature (18 degrees C) was characterized by a feed intake of 3.75 g (DM)/fish/day; digestibility values were as follows: dry matter 66.08 p. 100, nitrogen 89.57 p. 100, energy 73.52 p. 100. The daily patterns in digestibility were affected by the rise in temperature. The digestibility values were stabilized by day 7 after the positive thermal shock.

Animals↗
PubMed1981

[In vivo protein synthesis in rainbow trout (Salmo gairdneri R.) muscle. Effect of temperature acclimatization].

Protein synthesis was measured in the muscle of trout acclimatized to 10 and 18 degrees C and weighing about 100 g. Fractional synthesis rate was calculated after a pulse injection of L-leucine U14C by fitting the specific radioactivity of the protein to the computed values obtained with the specific radioactivity of the precursor, according to a precursor product relationship (Martin et al., 1977). At 10 and 18 degrees C, fractional synthesis rate values were 0.9 and 1.2 p. 100/d (plasma as the precursor pool) and 1.9 and 1.8 p. 100/d (intracellular pool as the precursor), respectively. Muscle protein synthesis rates in young trout are lower than in young mammals (rat, rabbit, lamb), and temperature acclimatization had no influence on muscle protein synthesis in trout.

Acclimatization↗
PubMed1979

Influence of dietary amino acid patterns on the free amino acid contents of blood and muscle of rainbow trout (Salmo gairdnerii R.).

1. Groups of rainbow trout were given one or other of two diets that differed in amino acid profile for two months; concentrations of free amino acids in whole blood and latero-dorsal muscle were then measured. The effects of temperature (12 and 18 degrees C in freshwater) and salinity on the concentrations of free amino acids in these tissues were also observed. 2. Although both diets apparently met the essential amino acid requirements of the trout and were isoenergetic, they nevertheless had different nutritional values for trout. 3. Patterns of free amino acids in tissues of trout given the two diets were different. Blood and muscle amino acid fractions were affected differently by changes in dietary amino acids.

Amino Acids↗
PubMed1979

Effect of dietary fatty acids differing by chain lengths and omega series on the growth and lipid composition of turbot Scophthalmus maximus L.

1. A previous paper (Gatesoupe et al., 1977) showed that turbot had a specific requirement for omega 3HPUFA since equivalent dietary amounts of 18:3 omega 3 or omega 3HPUFA (0.55% of the diet) did not lead to the same growth performances. 2. In the present paper, we demonstrated that fish given a high level of dietary 18:3 omega 3 (3.7% of the diet), without omega 3HPUFA, presented better growth than those offered a lower level of 18:3 omega 3, and almost the same performances as fish receiving 0.57% omega 3HPUFA. 3. This suggested that turbot, like trout, might be able to use the 18:3 omega 3 as a precursor of the omega 3 series. Furthermore, according to the present relatively short-term experiment, elongation-desaturation reactions of the omega 3FA did not appear to be reduced with low dietary omega 3FA levels. 4. On the other hand, these types of reactions seemed to be totally missing with the 18:2 omega 6. Thus, it may be assumed that there was no direct relationship between growth and omega 3 elongating-desaturating activities, and that omega 3 lowering fish body content was not the cause, or at least not the only cause, of poor growth in long-term experiments.

Animals↗
PubMed1977

Specific distribution of fatty acids in the triglycerides of rainbow trout adipose tissue. Influence of temperature.

In the trout, the unsaturated fatty acids are preferentially located in the beta-position and the saturated fatty acids in the alpha-position of triglycerides. This fatty acid distribution is retained even with diets containing lard. The fish are, therefore, able to modify completely the fatty acid distribution of dietary triglycerides. There is no retention of the beta-monoglyceride structure during the biosynthetic processes. However, the modification of the dietary fatty acid distribution by the trout seems to be more difficult at 18C than at 10C.

Adipose Tissue↗
PubMed1976

[Diet influence on growth-characteristics of the shrimp Crangon Crangon L., estimated by the evolution of nucleic acid content (author's transl)].

1. Young sand-shrimps having an initial weight of 63 mg were reared for 4 months with a natural diet (A) and a compounded diet (B). 2. Growth is studied, both by the evolution of the fresh weight and the variation of cell-number and cell-size; these are estimated from total DNA and fresh-weight/DNA ratio evolution. 3. With diet A, the mean weight increment is a linear function of time, the daily weight-gain being equal to 2.8 mg/day. The increase in total DNA content per shrimp is a linear function of fresh weight; its value goes up from 187 to 1020 micromoles. The fresh-weight/DNA ratio, initially equal to 337.9 (mg/micromoles) ,remains constant. For the whole experiment, growth is only a result of cellular multiplication. 4. With diet B, the weight gain is inferior to that observed with diet A. The fresh weight gain curves show two visibly homogenous steps, each with a distinct growth-rate; the mean daily weight gain is equal to 1.7 mg/day during the first two months, and equal to 2.6 mg/day for the two following months (fig. 1). In reality, from the total DNA and fresh-weight/DNA ratio evolution, 3 successive steps can be discerned (fig. 2, fig. 3). During the first month, total DNA increases from 187 to 418 micromoles and fresh-weight/DNA ratio falls down to 273.9, a-19% decrease. For this period, growth is only the result of cellular multiplication, and the decrease of the weight-gain in comparison with diet A is attributed to a decrease in cellular size. During the second month, as the fresh weight increases from 114.5 to 161.2 mg, total DNA increases from 418 to 519 micromoles and the fresh-weight/DNA ratio returns to its initial value. Two thirds of the growth is the result of cellular multiplication, and the rest being due to cell-size enlarging. For the last two months, as the mean fresh weight increases from 161.2 to 296.7 mg, the DNA per shrimp, hence the cell-number, remains constant; but the fresh weight/DNA ratio, or the cell-size, is multiplied by 1.93. 5. By the method used for this study, it is possible to evidence influence of diet on the growth mechanisms themselves (cellular multiplication and cell enlarging). 6. The influence of diet on the growth of the shrimp could be explained by, either a diet qualitative deficiency, or a food-intake decrease. The possibility of a hormonal control has been suggested.

Aging↗