Determination of the optimal digestible arginine to lysine ratio in Ross 708 male broilers

Published on: 09/08/2021
Author/s : A. Corzo 3, J. Lee 2, J. I. Vargas 1, M. Silva 3, and W. J. Pacheco 1. / 1 Department of Poultry Science, Auburn University, Auburn, AL 36849, USA; 2 C.J. Bio America, Downers Grove, IL 60515, USA; and 3 Aviagen, Huntsville, AL 35830, USA.

DESCRIPTION OF PROBLEM Broilers have specific essential amino acid requirements that must be met in order to support growth, muscle development, and meat yield (Mack et al., 1999; Zampiga et al., 2018). Continued genetic selection of broiler strains focused on increasing feed intake and meat yield and improving growth efficiency will require adjustments in formulation, particularly in amino acids...

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John Thomson John Thomson
Sales Director
AlzChem AlzChem
Trostberg, Traunstein, Germany
September 8, 2021
As a Nutritionist and having formulated a lot of diets over the years, I appreciate the desire to have a point estimate of the dArg/dLys ratio. I also appreciate your contribution toward that goal.

Given the low to extremely low R square values for your regression models, it would seem to me that the "optimal" ratios from your conclusions cannot be very precise. How would you advise formulators to use the point estimates you have provided? Is there some standard that should be applied to goodness-of-fit of a model used to make nutrient recommendations?
September 9, 2021
I congratulate the team of researchers involved in the idealization and implementation of this study, with emphasis on the methodology, especially in the number of birds per experimental unit and in the number of replicates. It is also worth highlighting the fact that the authors used suboptimal levels of lysine in the experimental diets, which makes total sense. Despite the positive aspects highlighted, I think that two treatments were missing. The first would correspond to a basal ration with all the nutrients, including lysine and arginine, meeting the requirement of the birds. And the second would correspond to a ration similar to the previous one with the suboptimal level of lysine, as established. These treatments would serve to prove that the suboptimal level of lysine compromised the performance of the birds
Alvaro Dubois Alvaro Dubois
Technical Consultant at Cargill
September 13, 2021
Congratulations for this splendid work. The number of birds analyzed for carcass is really impressive.

I just can't see from the numbers how you could get to a maximum response for carcass yield of 136 when the maximum value was attained at 109%. It looks like a broken-line (with a linear ascending term) would have been a better option and fit the data as well as the quadratic model.
Tawfik Tawfik
September 14, 2021

What is the recipe starter grow finisher you use for this result?

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Fred Hoerr
Fred Hoerr
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