The level and source of free-methionine affect body composition and breast muscle traits in growing broilers1

Abstract

Although dietary Met, as the first limiting amino acid (AA), has been extensively studied for poultry, little is known about how the supply and source of free Met affect tissue composition. The purpose of this study was to investigate the effect of feeding young broiler chickens with a deficient or sufficient TSAA (Met+Cys) supply, using either dl-Met (dl-Met+ and dl-Met-, for respectively diets sufficient and deficient in TSAA) or dl-2-hydroxy-4-methylthiobutyric acid (HMTBA+ and HMTBA-, for respectively diets sufficient and deficient in TSAA) as a Met source on tissue composition and breast muscle traits. For both Met sources, the deficient diets were formulated to provide true digestible Met:Lys and TSAA:Lys respectively 45% and 30% below that of the sufficient diets. Performance and tissue weights were affected by the Met supply but not by the Met source. In TSAA-deficient chickens, ADG and FCR, and protein content in empty body and pectoralis major muscles (PM) were lower than in TSAA-sufficient chickens (P < 0.05). Reducing the Met content of the diet increased the redness value of PM (a*) and the hue angle (H°; P < 0.01). The source of Met affected body AA composition and the partitioning of body Cys among tissues (P < 0.05). In TSAA-deficient birds, body Cys mass decreased in the commercial carcass and PM, but increased in the rest of the body (P < 0.01). The Met source also had an impact on the Cys mass, which was reduced in the commercial carcass and PM of dl-Met birds, but higher in the rest, especially in the feathers of TSAA-deficient birds (P < 0.05). The Met source, supply, or both altered the AA composition of the empty body, mostly in the commercial carcass. In conclusion, a dietary TSAA deficiency altered performance, tissue composition and quality traits of PM of broilers. There was no impact between dietary dl-Met and dl-HMTBA on performance or muscle weight, although the Met source affected the partitioning of Cys among tissues.

Gene expression differences in the methionine remethylation and transsulphuration pathways under methionine restriction and recovery with D,L‐methionine or D,L‐HMTBA in meat‐type chickens

“…The results from the current study show that there is a relationship between dietary Met and growth and this was consistent with previous studies (Conde‐Aguilera et al., ; Garber & Baker, ; Lepore, ). When birds were fed suboptimal dietary Met levels, growth significantly declined.…”

Effects of different methionine sources on growth performance, meat yield and blood characteristics in broiler chickens

“…In comparative study between MHA-Ca and MHA-FA in broiler chicks, the former exhibited higher methionine efficacy than the latter (Boebel and Baker 1982), although both forms were inferior to DLM. In contrast, equal bio-efficacy of MHA-FA (Elkin and Hester 1983;Liu et al 2006;Xi et al 2007;Swennen et al 2011;Conde-Aguilera et al 2016) or MHA-Ca (Bishop and Halloran 1977;Baker and Boebel 1980;Dilger and Baker 2008) compared with DLM has been also reported in broiler chicks. Nonetheless, it is common practice in feed industry to add MHA sources in the diets of chickens albeit that the bioavailability relative to DLM is still under controversy.…”

Age and Gender Dependent Amino Acid Concentrations in the Feather, Feather-Free and Whole Empty Body Protein of Fast Growing Meat-Type Chickens

“…But also feather structure and composition are age-dependent and individual morphological parts of fowl feathers show differences in AA composition [40] [48] [49] [50] [51]. In addition, also effects of diets deficient in branched chain AAs and methionine on AA content of the feather protein were reported [27] [43]. In case of deficient AA supply, feather protein synthesis is of superior priority [27] [52].…”

“…In addition, also effects of diets deficient in branched chain AAs and methionine on AA content of the feather protein were reported [27] [43]. In case of deficient AA supply, feather protein synthesis is of superior priority [27] [52].…”

“…Specifically, an age-dependent change of the whole body protein AA composition can be expected due to different allometric growth rates of individual body tissues and organs [7] [19] [20] [21]. Additionally, the dietary protein and AA supply can also impact on body AA composition [9] [10] [15] [22]- [27]. An increased accuracy in estimations of the adequate dietary AA supply could be achieved if substantial body protein fractions are initially investigated separately.…”