Stable isotopes to study sulfur amino acid utilization in broilers

Abstract

Nutritionists have been discussing whether the dietary supplementation of cyst(e)ine is required as a part of the dietary methionine (Met) in the total sulfur amino acid (TSAA) requirement to achieve optimum performance in broilers. Part of Met is converted to cysteine (Cys) to meet the Cys requirement, especially for feather growth. The TSAA requirement has been determined by using graded levels of free Met in the diet, without supplementation of free cyst(e)ine. It has also been argued that the Met to Cys ratio (Met : Cys) changes with age and even with different Met sources. The objective of this study was to evaluate the two sources of Met, while determining the proportion of Met and Cys in total dietary TSAA that optimize the performance of broilers. A performance assay was carried out in a factorial arrangement (5 × 2) using 1080 broilers from 42 to 56 days of age fed diets having different dietary proportions of Met and Cys (44 : 56, 46 : 54, 48 : 52, 50 : 50 or 52 : 48) while maintaining the same dietary TSAA in the diets. Two synthetic Met sources (dl-Met or l-Met) were used for each of the diets with different dietary Met : Cys ratios. Twenty-one broilers of the same age were fed the diets 44 : 56, 48 : 52 and 52 : 48 by supplementing the diet with L-(15N) Met or L-(15N2) Cystine to study the metabolism of TSAA. No differences were observed between Met sources for feed intake, BW gain and feed conversion ratio (FCR; P > 0.05); however, FCR was numerically improved at 50 : 50 Met : Cys. Regarding TSAA utilization, the conversion of Met to Cys increased with increase in Met : Cys ratios, but the concentration of Met intermediates decreased. Broiler chickens responded to different dietary proportions of sulfur amino acids by altering their sulfur amino acid metabolism, and diets containing 50 : 50 Met : Cys is recommended for broilers of age 42 to 56 days.

Effect of dietary digestible sulphur amino acids level on growth performance, blood metabolites and liver functional enzymes of broilers 1–11 days of age

“…This occurs through the transsulphuration pathway in which the sulphur of Met is transferred to serine, thereby yielding Cys. Therefore, it can be determined SAAs requirement by using graded levels of Met in the diet without supplementation of Cys (Suzuki et al 2020). It has been well documented that broiler diets based upon soybean meal as the primary protein source are deficient in the SAAs (Ahmed and Abbas 2011;Goulart et al 2011;Faridi et al 2016).…”

Biological influence of nanotechnological j, se, s citrates in broiler chickens in the second period of rearing

“…Це дозволило встановити мінімальні фізіологічно активні дози та співвідношення нанотехнологічних цитратів J, Se, S для використання їх як БАД у технології вирощування курчатбройлерів. Відомо, що J, Se, S, як елементи мінерального живлення, відіграють важливу регуляторну роль в метаболічних реакціях щитоподібної залози (ЩЗ), функціонуванні низки фізіологічних систем і органів, процесах травлення, розмноження та адаптації [1,6,16,22,28]. Зокрема, J є важливим елементом функціонування гіпофіз-тиреоїдної системи, що в іонному стані впливає на білковий, ліпідний, водно-електролітний і енергетичний обмін, бере участь у коригуванні репродуктивної й онтогенетичної здатності та продуктивності [17].…”

Threonine incorporation in tissues of growing broiler chickens using L‐[15N] threonine

“…Nitrogen content and stable nitrogen isotope ratios were determined on Delta S Isotope Ratio Mass Spectrometer equipped with an elemental analyser (EA-IRMS; Finningan MAT). Because of the low analytical error (about 0.01 ~ 0.02‰), we used three replicates per collection point as used in other isotope studies (Pacheco et al, 2018;Suzuki et al, 2020).…”