Interesting read, John.
I guess the crux falls down to Amino?
Obviously, it also depends on what the fish is eating at any given time, just as it stands to reason that the size of the fish should be taken into account.
With over 100 Amino Acids to choose from within nature, the protein count of structures to build a protein is almost infinite, yet only 20 Amino Acids (EAA and NEAA) are required to sustain Carp, and even then, the total of 20 is a contentious figure to quote, however, working on the assumption of the 20 (*10 EAA* and 10 NEAA), research carried out by the learned has produced some marvellous reading.
On a daily basis, all things considered, and the Carp is a healthy fish, the daily requirement to maintain a healthy body is estimated to be very close to 1g per kilo of body weight, and for maximum Protein retention it is estimated to be 12g per kilo of body weight. However, the efficiency of Nitrogen utilization for Carp growth is estimated to be between 7g and 8g per kilo of body weight, with Crude Protein ranging from 30% to 38% being the optimal. As stated previously, this depends entirely on the diet that the Carp is eating and providing the diet contains sufficient digestible energy, the optimal Protein level can drop from 30%-38% to a level of between 30% and 35%.
As mentioned above, the required intake differs depending on fish size, health of the fish at time of feeding, but studies carried out has given results as such:
Essential Amino Acid daily requirements
Arginine ---------- 4.3% of Protein ------------- 6.4% of Diet
Histidine-----------2.1% of Protein ------------- 0.8% of Diet
Isoleucine --------2.5% of Protein --------------0.9% of Diet
Leucine -----------3.3% of Protein --------------1.3% of Diet
Lysine -------------5.7% of Protein --------------2.2% of Diet
Methionine -------2.1% of Protein --------------0.8% of Diet
Phenylalanine ---3.4% of Protein --------------1.4% of Diet
Threoline ---------3.9% of Protein --------------1.5% of Diet
Trytophan --------0.8% of Protein --------------0.3% of Diet
Valine -------------3.6% of Protein --------------1.4% of Diet
Cysteine and Tyrosine can spare or even replace certain amounts of dietary requirement as is Methionine and Phenylalanine and as such, the reading(s) where relevant is thus:
Cysteine ----------5.2% of Protein --------------2.0% of Diet
Tyrosine ----------2.6% of Protein ---------------1.0% of Diet
*The figure 10 EAA could be 9 EAA and 11 NEAA due to inconclusive study into Histidine. Some research states it is EAA whilst other research has stated it could be NEAA. Either way, it is, for topical debate in this conversation, being classed as an EAA.
I 100%, whole-heartedly agree with your comment regarding bait, John. If you don't know what you're feeding them, how do we know it is good for them?