Dietary methioninesources bioefficacy in broilers: effect of acidified diet and rearing system

Abstract

The objective of this study was to evaluate the bioefficacy and the effects of the supplementation of different sources of methionine on the performance, redox status, development and pH of the gastrointestinal tract (TGI) and plasma concentrations of uric acid and creatine kinase in Broilers maintained in different breeding systems. (floor and cage). The treatments were: 1) basal diet (DB) without methionine supplements, 2-6) 0.05 supplements; 0.10; 0.15; 0.30; 0.35% DLM, 7-11) Supplementation 0.05; 0.10; 0.15; 0.30; 0.35% DLM + AO, 12-16) 0.05 supplementation; 0.10; 0.15; 0.30; 0.35% HMTBA. Article 1 presents the results for broilers. Considering the entire experimental period, the bioefficacy of HMTBA and DLM + AO was 70% and 121%, respectively. The shear force increased in the breasts of birds that received diets deficient in Met. All birds fed any source of Met showed an increase (P <0.05) in hepatic and intestinal concentrations of glutathione peroxidase (GSH), catalase (CAT) and superoxide dismutase (SOD) and a reduction (P <0.05) of lipid peroxidation in comparison. with chickens fed with DB without supplementation. In the initial phase (1-21 days) broilers supplemented with DLM and DLM + AO showed increases (P <0.05) in the Vilo / Crypt ratio compared to chickens fed with HMTBA. However, at 42 days, birds supplemented with HMTBA and DLM + AO exhibited a better intestinal development by presenting an increase (P <0.05) in the Vilo / Crypt ratio. The pH of the gizzard and jejunum was lower in broilers that received HMTBA and DLM + AO. Supplementation of any source of Met significantly decreased (P <0.05) plasma CK levels. However, on day 42, HMTBA and DLM + AO showed lower CK activity in the blood. On the other hand, uric acid (AU) concentrations increased significantly (P <0.05) on day 42 in birds that received any source of methionine. Therefore, Met supplementation improves performance, redox status and intestinal development. Finally, the use of organic acid improved the bioefficacy of DLM. In Article 2, the results corresponding to broilers are discussed. The bioefficacy of HMTBA was 59% and DLM + AO 132%. The shear force increased (P <0.05) for BD and there was a tendency for chickens fed with deficient levels of Met. Supplementation of any source of Met stimulated the production of GSH, CAT, SOD (P <0.05) and, consequently, decreased (P <0.05) lipid peroxidation. On day 21, chickens fed DLM and DLM + AO showed increases (P <0.05) in the Vilo / Crypt ratio compared to chickens fed HMTBA. Already on day 42 there were no significant differences between the sources of Met. The pH of the gizzard and jejunum were lower (P <0.05) in broilers that received HMTBA and DLM + AO. There was no significant influence (P> 0.05) of treatments at UA levels during the experimental period. At 21 days, supplementation with DLM and DLM + AO further decreased CK levels (P <0.05). However, at 42 days there were no significant differences (P> 0.05) between the sources. Therefore, it can be concluded that, regardless of the breeding system, the addition of organic acid adds the DLM bioefficacy and, consequently, the performance and physiological parameters of the birds.