Karl-Heinz Kiessling

Changes in the structure and function of the epaxial muscle of rainbow trout (Oncorhynchus mykiss) in relation to ration and age: I. Growth dynamics

Abstract Growth of white and red muscle fibres was studied in a feeding ration experiment with rainbow trout, from hatching until sexual maturity (2.5 years). The trout were fed ration levels (RL) which ranged from appreciable underfeeding to overfeeding (RL=25% and 200% of full ration, respectively). They were also subjected to changed rations in order to study adaptation effects and recovery growth. The ratio of carcass to body weight (CW%) indicated that in young fish (0.3 year) on a restricted ration, growth of internal organs was favoured compared with that of total muscle. In older fish all groups, irrespective of ration, increased their carcass to body ratio until saltwater adaptation (1.0 year) and thereafter a sharp decline was noted. No decrease was seen in fish remaining in freshwater. There was a high correlation between body length and the length ( r 2 =0.99), width ( r 2 =0.97) and height ( r 2 =0.96) of the muscle, and also of the diameter ( r 2 =0.86-0.93) and length ( r 2 =0.94) of individual white muscle fibres. In fish with a body length less than 250 mm, red fibre diameter was more closely related to ration level than to body length and vice versa in larger fish. In large fish, recruitment of small fibres was seen in all muscles studied. However, periods of rapid growth favoured fibre hypertrophy and periods of slow growth fibre recruitment. Significant differences were found between the lateral and the dorsal parts of the white epaxial muscle, suggesting different growth rates in the two muscle areas.

Changes in fatty acid composition in muscle and adipose tissue of farmed rainbow trout (Oncorhynchus mykiss) in relation to ration and age

To evaluate the importance of age and feed ration level (RL) on the composition of tissue fatty acid (FA) in rainbow trout (Oncorhynchus mykiss), fish were fed rations ranging from appreciable underfeeding to gross overfeeding in a longitudinal experiment lasting from start of feeding to onset of sexual maturation 2.4 years later. In order to study the effects of compensatory growth and reduced feed availability, fish were moved from high to low ration and vice versa. Changes of individual FA of total lipid (TL), triacylglycerols (TAG) and total phospholipids (PL) were studied in white and red muscle, as well as in three major adipose tissues. The effect of saltwater transfer on FA composition was also examined. A strong interdependence was found between the relative proportion of PL and TAG with changes in TL content. This was most prominent in white muscle. In parallel with this change in relative lipid class composition, a major effect was seen on FA in the TL fraction. The most marked effect of RL was an inverse relationship between 22:6 n-3 of the PUFA n-3 series and 16:1 and 18:1 of the MUFA series. This was seen in all tissues studied. It is suggested that the most important factor governing FA composition in muscle, pending changes in feed intake, is the TL content, affecting the relative level of PL and TAG. In adipose tissue, consisting mainly of TAG, more subtle changes were observed. The FA compositions of PL and TAG were not affected to any major extent by RL, except at extreme reductions. Significant changes in FA of PL and TAG were observed as an effect of saltwater transfer.

Seasonal variation in catabolic enzyme activities in breast muscle of some migratory birds

SummaryFive bird species were examined in order to ascertain if any changes in flight muscle catabolism take place between breeding season and migration. Two different patterns were discovered. The first consists of a high oxidative capacity and a low glycolytic and anaerobic capacity during migration. The converse occurs during the breeding season, i.e. low oxidative, high glycolytic and anaerobic capacity. The pattern was found in those species that deposit large amounts of fat prior to migration. The second pattern was similar to the first, but there was no change in fatty acid oxidation capacity between breeding season and migration. The pattern was found in those species that do not deposit much fat towards migration. These changes are believed to reflect differences in migration strategy and differences in locomotory activity during different seasons. Deviations from these patterns are discussed.

Changes in the structure and function of the epaxial muscle of rainbow trout (Oncorhynchus mykiss) in relation to ration and age. III, Chemical composition

Abstract The chemical composition of white and red muscle has been studied in rainbow trout in relation to age and ration level (RL), together with the deposition and mobilization of fat from the three main adipose tissues (viscera, dorsal and abdominal wall). Protein in red and white muscle increased with age up to 1.4 years and remained practically constant from then on, irrespective of ration level. In all tissues studied, fat content increased with age until a final steady level was reached, dependent on ration level and tissue. In white muscle and viscera, however, this increase was preceded by a decrease in fat content (0.3–1.1 years). Subjecting fish to a new RL resulted in a change in the fat content to the same level as that in fish fed at this RL from the start. The total amount of fat was regulated in all tissues, except visceral adipose tissue, by altering the relative fat content rather than by increasing or decreasing the relative size of the tissue. Overall changes in dry matter content, from hatching to sexual maturation, correlated mainly with protein in white and with fat in red muscle. However, when young and older fish were studied separately it became apparent that a change in protein content was closely related to changes in dry matter in both muscle types early in life (fish 1.1 years). The glycogen level varied in parallel in red and white muscle, except for the large increase in white versus red muscle after the glycogen depletion in connection with saltwater transfer. Subjecting fish to a new RL caused rapid changes in glycogen content in young specimens. Underfed fish produced markedly elevated levels of muscle glycogen. Season, sex or sexual maturation had no effect on the chemical composition of the muscle.

Catabolic enzyme activities in the pectoralis muscle of premigratory and migratory juvenile Reed Warblers Acrocephalus scirpaceus (Herm.)

SummaryDifferences in catabolic capacity in the pectoralis major muscle of premigratory and migratory Reed Warblers were examined. The oxidative capacity was greater in the migratory birds, probably reflecting a “training effect” caused by the increased locomotion activity just prior to migration.Fatty acid oxidation was already high in the premigratory birds, possibly reflecting a saving of carbohydrate for anabolic purposes (feather growth) during the moult. Glycolytic capacity was slightly increased in the migratory birds, suggesting an increased carbohydrate oxidation during migration in spite of the great contribution of fatty acid oxidation.

Effects of Starvation on Rainbow Trout Muscle

Abstract This study deals with the effects of up to three months starvation on white and red muscle in mature and immature rainbow trout. Examined in the study were the histochemistry of the muscle, the dynamics of muscle fiber growth, key enzymes involved in energy metabolism and the chemical composition. Muscle fibers in the different muscle tissues did not respond to starvation in a consistent way. In red muscle starvation induced a narrowing of the range of fiber sizes, regardless of the stage of maturation of the fish. In white muscle of immature fish starvation for 3 months had no effect on fiber sizes whereas in sexually mature fish the fiber cross section areas were smaller than expected based on the weight of the fish. This was probably caused by a pronounced break down of muscle protein in mature fish for gonad formation and energy production without a simultaneous replacement of protein by water. Pink muscle in immature fish showed a response intermediate between red and white muscle. Starvatio...

Changes in the structure and function of the epaxial muscle of rainbow trout (Oncorhynchus mykiss) in relation to ration and age: II. Activity of key enzymes in energy metabolism

Abstract The activity levels of four enzymes, representing vital energy-creating pathways (glycolysis by phosphofructokinase, β -oxidation by 3-hydroxyacyl-CoA dehydrogenase, citric acid cycle by citrate synthetase and the respiratory chain by cytochrome oxidase), were measured from hatching to sexual maturation. The activities of all enzymes investigated were affected more by age than by ration level. Only in fish kept on very restricted rations were reductions in activity levels noted. However, phosphofructokinase activity in white muscle decreased significantly also at moderately restricted ration levels. From 0.3 to 1 year of age, enzyme activities of glycolysis increased in white and decreased in red muscle while the opposite was true for enzymes in the β -oxidation and citric acid cycle, indicating an ongoing differentiation process as regards substrate utilization in the two muscle types. An increase in the respiratory chain in both muscle types during this period suggests an increased importance of aerobic catabolism of the different substrates. Enzyme activities decreased markedly at the time of saltwater transfer, with the exception of white muscle glycolytic activity. An increase in enzyme activities in red muscle occurred between 2 and 2.4 years, but no relation was observed between sex or degree of maturation and enzyme activity.

Comparative aspects of fibre types, areas, and capillary supply in the pectoralis muscle of some passerine birds with differing migratory behaviour

SummaryFibre types, fibre areas and capillary supply in the pectoralis muscle of fifteen passerines with four different patterns of migratory behaviour have been studied. The predominant fibre type was a fast-twitch oxidative-glycolytic which was the only fibre type present in all species, except in the robin and the blackbird where a fast fibre with intermediate oxidative capacity and a fast glycolytic fibre were also found. There was a significant difference in fibre areas between birds with different migratory strategies, with the long-distance migratory group having the smallest fibres. This also led to higher capillary densities, shorter diffusion distances and, consequently, more capillaries around the fibres relative to fibre area in this group. This indicates an adaptation in the morphology of the pectoralis muscle to differences in migration strategies. In the robin, the proportion of the intermediate fibre was significantly greater during the breeding season than during migration. Seasonal differences in fibre areas and capillary supply within a species were also seen, but no definite trends were detectable.

Fibre composition and enzyme activities in five different muscles from the Svalbard reindeer

beta R fibres (type I) constitute less than 10% of the semimembranosus and longissimus dorsi muscles and about twice as much of the gluteobiceps and flexor hallucis. Except for longissimus dorsi, 50% or more consist of alpha W (type IIB) fibres--in semimembranous, as much as 70%. Despite the comparatively large content of alpha W fibres, both the oxidative capacity and the capacity to metabolize fatty acids is high. Furthermore, unexpectedly small differences in oxidative capacity between the three fibre types beta R, alpha R and alpha W (I, IIA and IIB) are revealed by histochemical staining. These results indicate a tendency to bring the three fibre types closer together as regards metabolic activities, as an adaptation to the relatively tranquil life of this animal. However, the large content of alpha W fibres does not accord well with this way of life, as they guarantee quick movements. The comparatively high oxidative capacity of the alpha W fibres in the Svalbard reindeer and the fact that during starvation it is primarily alpha W fibres that contribute to the energy supply by protein degradation may nevertheless account for their abundant occurrence.

Physiological changes in muscle of rainbow trout fed different ration levels

Abstract The effects of different ration levels on muscle growth dynamics and activity of metabolically important enzymes in the muscle of rainbow trout ( Salmo gairdneri Rich.) were investigated in a study lasting from startfeeding throughout life. Three experimental ration levels, adequate feeding, moderate restriction and strong restriction, were defined according to expected growth. Groups of trout were maintained at constant experimental ration levels in order to study short-term or long-term effects, or subjected to changed levels to study compensatory effects. In this paper results from the first year of the ongoing experiment are presented. Somatic growth increased with increasing rations. No compensatory growth was observed in groups transferred from restricted to adequate feeding. Fiber area in white muscle was correlated with body weight, indicating a growth mechanism in white muscle based on fiber enlargement. This conclusion is further supported by fiber size distribution. In red muscle, fiber area had a strong correlation with ration level. Protein and water content were stable. Glycogen varied with changed ration level. The activity of phosphofructokinase in white muscle as well as 3-hydroxyacyl-CoA dehydrogenase, citrate synthetase and, to a lesser degree, cytochrome oxidase in red muscle changed with altered ration level.