The Revista Brasileira de Zootecnia (RBZ) is a publication dedicated to the broad field of Animal Science. We publish high-quality, original scientific research that spans across diverse areas within the discipline. The scope of RBZ encompasses a wide range of topics, including aquaculture, biometeorology and animal welfare, forage crops and grasslands, animal and forage plants breeding and genetics, animal reproduction, ruminant and non-ruminant nutrition, meat science and muscle biology, precision livestock, and animal production systems and agribusiness.
The Revista Brasileira de Zootecnia (RBZ) is a publication dedicated to the broad field of Animal Science. We publish high-quality, original scientific research that spans across diverse areas within the discipline. The scope of RBZ encompasses a wide range of topics, including aquaculture, biometeorology and animal welfare, forage crops and grasslands, animal and forage plants breeding and genetics, animal reproduction, ruminant and non-ruminant nutrition, meat science and muscle biology, precision livestock, and animal production systems and agribusiness.
The Revista Brasileira de Zootecnia (RBZ) is a publication dedicated to the broad field of Animal Science. We publish high-quality, original scientific research that spans across diverse areas within the discipline. The scope of RBZ encompasses a wide range of topics, including aquaculture, biometeorology and animal welfare, forage crops and grasslands, animal and forage plants breeding and genetics, animal reproduction, ruminant and non-ruminant nutrition, meat science and muscle biology, precision livestock, and animal production systems and agribusiness.
The objective of this experiment was to establish different criteria to evaluate the requirements of digestible tryptophan for broilers from 22 to 42 d of age, using different regression models (quadratic, exponential and Linear Response Plateau) and in case of statistical significance the comparison of means by Duncan test at 5% probability was also adopted. A total of 1,920 Cobb 500 male broilers were distributed in a completely randomized experimental design, with 6 treatments (6 digestible tryptophan levels: 0.1395, 0.1610, 0.1825, 0.2040, 0.2255 and 0.2470%) and 8 replications containing 40 broilers each. Performance and carcass characteristics were evaluated. The level of 0.2255% of digestible tryptophan numerically improves feed conversion, and the 0.1919% estimated by the quadratic equation significantly improves carcass yield.
Digestible tryptophan requirements for broilers from 22 to 42 days old
Duarte,Karina Ferreira and Junqueira,Otto Mack and Filardi,Rosemeire da Silva and Siqueira,Jefferson Costa de and Puzotti,Maíra Mangili and Garcia,Edivaldo Antônio and Molino,Andrea de Britto and Laurentiz,Antonio Carlos de. Digestible tryptophan requirements for broilers from 22 to 42 days old. R. Bras. Zootec. [online]. 2013, vol.42, 10, [cited 2026-04-23], pp.728-733. Available from: <https://rbz.org.br/article/digestible-tryptophan-requirements-for-broilers-from-22-to-42-days-old/>. ISSN 1516-3598. http://doi.org/10.1590/S1516-35982013001000006.
Duarte,Karina Ferreira; Junqueira,Otto Mack; Filardi,Rosemeire da Silva; Siqueira,Jefferson Costa de; Puzotti,Maíra Mangili; Garcia,Edivaldo Antônio; Molino,Andrea de Britto; Laurentiz,Antonio Carlos de. Digestible tryptophan requirements for broilers from 22 to 42 days old. R. Bras. Zootec., v.42, 10, p. 728-733. Oct. 2013. Available from: <https://rbz.org.br/article/digestible-tryptophan-requirements-for-broilers-from-22-to-42-days-old/>. acess on 23 Apr. 2026. http://doi.org/10.1590/S1516-35982013001000006.
Duarte,Karina Ferreira, & Junqueira,Otto Mack, & Filardi,Rosemeire da Silva, & Siqueira,Jefferson Costa de, & Puzotti,Maíra Mangili, & Garcia,Edivaldo Antônio, & Molino,Andrea de Britto, & Laurentiz,Antonio Carlos de. (2013). Digestible tryptophan requirements for broilers from 22 to 42 days old. R. Bras. Zootec., 42(10) , 728-733. http://doi.org/10.1590/S1516-35982013001000006.
DuarteKarina Ferreira, JunqueiraOtto Mack, FilardiRosemeire da Silva, SiqueiraJefferson Costa de, PuzottiMaíra Mangili, GarciaEdivaldo Antônio, MolinoAndrea de Britto, LaurentizAntonio Carlos de. Digestible tryptophan requirements for broilers from 22 to 42 days old. R. Bras. Zootec. [Internet]. 2013 Oct [cited 2026 Apr 23]; 42(10): 728-733. Available from: https://rbz.org.br/article/digestible-tryptophan-requirements-for-broilers-from-22-to-42-days-old/. http://doi.org/10.1590/S1516-35982013001000006.
Figure 6
Differential abundance for the species Faecalibacterium prausnitzii (A) and Megamonas funiformis (B).
