Das ideale Verhältnis zwischen Lysin, Methionin, Threonin, Tryptophan, Isoleucin und Arginin im Legehennenfutter

Interactions of various supplies of isoleucine, valine, leucine and tryptophan on the performance of laying hens

The present study was undertaken to investigate the interactions among the supplies of isoleucine, leucine, valine, and tryptophan in laying hens. A three-factor trial was conducted with laying hens in which the dietary concentrations of isoleucine (5.7, 8.0, and 11.5 g/kg), valine and leucine (6.3 and 7.2 g/kg and 10.1 and 11.5 g/kg, respectively), and tryptophan (1.5 and 2.4 g/kg) were varied. At the lowest concentration of valine + leucine, an increase in dietary isoleucine concentration led to a dose-dependent reduction in feed consumption, daily egg mass, and body weight gain and an increase of the isoleucine concentration in plasma. At a high dietary concentration of valine + leucine, excess dietary isoleucine concentration caused only a weak depression of performance parameters; the isoleucine concentration in plasma was independent of the dietary isoleucine concentration. Increasing the dietary tryptophan concentration did not influence the effect of an excessive dietary isoleucine concentration on performance parameters. Increasing the tryptophan concentration from 1.5 to 2.4 g/kg diet did, however, lead to a significant increase in feed consumption, irrespective of the supply of isoleucine, valine, and leucine. In conclusion, our study demonstrates that the supply of valine + leucine influenced the effects of excess dietary isoleucine in laying hens, whereas the supply with tryptophan did not.

Estimates of essential amino acid requirements from dose-response studies with rainbow trout and broiler chicken: effect of mathematical model

A total of 37 dose-response experiments with essential amino acids performed with rainbow trout and broiler chicken were re-evaluated with different mathematical approaches: an exponential model, a four-parameter logistic function, the saturation kinetics model and the broken line approach. The different approaches were compared both with regard to the goodness of fit (r2 and sy.x) and with regard to the allowances which were derived regarding the optimal amino acid level in the diet. The experimental design, particularly the chosen range in dietary amino acid concentration was found to be important for the comparison of models. Amongst the non-linear models, the four-parameter logistic function and the saturation kinetics model appeared superior to the exponential approach, when the range in dietary amino acid concentration was very wide and included both a severely deficient basal level and a level that exceeded the needs of the animal by approximately the factor 2. In these cases, allowances derived from individual experiments were considerably different depending on the model. The allowances based on the exponential and the saturation kinetics approach were 27.7 and 20.7 g lysine/kg DM and 8.0 and 6.3 g methionine/kg DM, respectively, for rainbow trout. For other amino acids studied in rainbow trout the difference due to model was less. Consequently, the predicted 'ideal protein' for rainbow trout was considerably different depending on the model used. The maximum deviation found in different experiments with broiler chicken for the exponential vs. the saturation kinetics approach was 13.0 and 9.7 g lysine/kg and 11.4 and 8.2 g sulfur-containing amino acids/kg, respectively. However, the more restricted the range in dietary concentration was, the lesser became the differences between the different non-linear models. No definite recommendation can therefore be extracted regarding the most suitable, generally applicable mathematical model.

Response of rainbow trout (Oncorhynchus mykiss) to supplements of individual essential amino acids in a semipurified diet, including an estimate of the maintenance requirement for essential amino acids

We studied the effects of increasing dietary concentrations of each of the following amino acids on growth, feed intake, feed conversion ratio and composition of gain in rainbow trout in six dose-response experiments: L-lysine, L-tryptophan, L-histidine, L-valine, L-leucine and L-isoleucine. Semipurified diets containing 20.1 MJ digestible energy/kg dry matter, with wheat gluten and crystalline amino acids as sole sources of amino acids, were fed to rainbow trout [initial mean body weight (BW) 40-51 g, depending on the amino acid studied]. In one series of 24 diets, lysine concentration ranged from 4.5 to 58.0 g/kg dry matter; in five further series of 12 diets each, concentrations ranged from (in g/kg dry matter): tryptophan, 1.3 to 5.6; histidine, 2.6 to 13.5; valine, 6.2 to 34.2; leucine, 10.0 to 42.0 and isoleucine, 5.0 to 15.3. Each diet was fed to a group of 20 fish for 53-64 d, depending on the amino acid studied. Dry matter intake, weight gain, feed conversion ratio, protein concentration of gain and total protein deposition followed exponential response functions. To achieve 95% of the maximum protein deposition, dietary concentrations of 27.7 g lysine, 2.0 g tryptophan, 5.8 g histidine, 15.7 g valine, 13.6 g leucine and 13.7 g isoleucine/kg dry matter were required. Maintenance requirements, estimated from exponential functions for protein deposition, were [in mg/(100 g BW.d)]: lysine, 1.93; tryptophan, 1.05; histidine, 1.07; valine, 2.92; leucine, 8.26 and isoleucine, 0.91. This corresponds to 4% of the requirement for protein deposition for lysine and isoleucine but 32% for leucine, with the other amino acids being intermediate. Therefore, different dietary amino acid requirement patterns were derived from protein deposition data depending on the chosen level of performance.