Digestible lysine levels obtained by two methods of formulation of diets for 22-to-42-day-old broilers

Congratulations on such a nice article, great information. Kindly help me understand that the diets either supplemented or without supplemented industrial Lysine were isocaloric and isonitrogenous, as it seems difficult to balance energy and protein ratio to achieve 12mg/kg dig. Lysine levels without supplemented industrial Lysine.

Congratulations to the team. This is indeed an excellent paper and demonstrates clearly how difficult it is to obtain optimum performance in broilers with diets low in crude protein. The only remark I would do is the lack of information on Gly+Ser levels. Including these two amino acids in the ones that had their minimum level (or ratio to lysine) guaranteed might have produced somewhat better results for the supplemented set of diets. There's quite an amount of information showing that these amino acids become deficient when reducing crude protein in broiler diets especially in corn+soybean vegetable diets as used in this trial. Also, the ratio of essential to non-essential amino acids would be nice information that might help the discussion of results.

The guide and the main amino acid for the broiler is lysine and also is essential for the flesh and the frame in between 0.9 to 1.2% is enough for the good performance for broiler apart from the limits in the raw materials.

The diet with lower protein and without supplementation of synthetic amino acids are better in today's situation. There is better balance of amino acids specifically non essential amino acids which are equally important for protein synthesis.Giving high digestible lysine and balancing other essential amino acids is very expensive proposition. There is marginal difference in the performance of bird but we can reduce quantum of expensive feed ingredient just to have better performance.

Mangalmurti Pathak

Adopting the practice of reducing the level of crude protein (PB) in the diet, without the proper supplementation of amino acids (Aas), will certainly reduce the rate of deposition of PB in the carcass, which will reflect negatively on weight gain (GP) and the feed efficiency (AE) of the birds. This means that in addition to reducing the GP, the amount of food spent per unit of gain increases, which makes it difficult to adopt this practice.
It must also be considered that it does not seem correct to me to say that the balance of Aas is better in the diet with reduced BP, without the proper amino acid supplementation. This is based on the fact that the supplementation of essential Aas, in accordance with the proposed relationships in the ideal protein, added to the nitrogen supply, using non-essential Aas, ensuring an adequate relationship between essential Aas and non-essential Aas, results in a better amino acid balance, comparatively.
I doubt if I understood your considerations.

Mangalmurti Pathak
With the complementary information, it seems to me that the proposal is to provide a diet with a suboptimal level of lysine, correcting the other essential amino acids that are necessary, according to their relationship with the lysine proposed in the ideal protein for the animal category, in addition to maintain the lysine relationship with energy. It was also defined that the reduction of the protein level would not compromise the relationship between essential amino acids and non-essential ones in the diet. If these considerations are correct, the challenge would be to establish the level of protein reduction in the diet, ie lysine, which could result in a better economic return, compared to the diet with an adequate level of lysine with amino acid supplementation. The difficulty is in establishing a correlation between the level of lysine in the diet with growth efficiency and meat yield in poultry carcasses.