Effect of dietary digestible lysine level on growth performance, blood metabolites and meat quality of broilers 23–38 days of age

Abstract

This study was done to evaluate the effects of different dietary digestible lysine (dig Lys) levels on growth performance, blood metabolites, carcass and breast yield, and breast meat quality of broilers 23–38 days of age. Three hundred 23‐day‐old Cobb‐500 male broiler chickens were allocated to a completely randomized design with five treatments (finisher diet containing 0.88%, 0.94%, 1.00%, 1.06% and 1.12% dig Lys) and six replicates of 10 birds each. Feed intake (FI) was not affected by different dietary dig Lys levels. Weight gain (WG) linearly increased and feed conversion ratio (FCR) linearly decreased with an increasing dietary dig Lys levels. With increasing dietary dig Lys levels, carcass and breast yield and breast meat hue angle (h*) linearly increased, but abdominal fat decreased quadratically, whereas breast meat lightness (L*) and ether extract composition linearly decreased. Dietary dig Lys levels did not show any significant effect on serum metabolites, breast meat cooking loss and water holding capacity. Based on the linear broken‐line regression models, the weight gain, feed conversion ratio and breast yield were optimized when dietary dig Lys levels were 0.95%, 1.01% and 1.02% respectively. It is concluded that Lys requirements vary according to what productive parameter is taken for optimization. A minimum of 1.02% dig Lys concentration in the finisher diet is suggested to optimize breast yield, feed efficiency and performance in broiler chickens.

Effect of protein concentrations in the diet on productive performance, carcass characteristics, and meat chemical composition of broiler chickens in the dry subtropics

“…Contrary to the observations of the present study, Ghazanfari et al (2010) observed that in broilers that incremental changes in dietary protein levels did increase feed intake and improved weight gain and feed conversion, compared with a low level of protein in the diet. Jafarnejad et al Improved productive performance of broiler chickens has been observed when increased over NRC recommendation the levels of lysine (Oliveira et al, 2013;Bernal et al, 2014;Quadros et al, 2019;Zarghi et al, 2020) and methionine plus cystine (Goulart et al, 2011). In the current study, the increase in crude protein increased the lysine concentration in the diets over the NRC recommendations; however, the crude protein increase in diets did not have evident increase on the levels methionine plus cystine in the used diets over the NRC recommendations.…”

“…higher lysine levels than NRC recommendations promoted breast meat yield (Bernal et al, 2014;Zarghi et al, 2020). In the current study all diets were supplemented with the same lysine level and covered the NRC recommendation and the increase in CP level in diets had small increases in lysine or methionine plus cystine.…”

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

“…The carcases were eviscerated manually and obtained by removing the head, feathers, feet, visceral organs, and gastrointestinal tract. The whole carcase was weighed and cut according to the procedure (Zarghi et al 2020a). Carcases and cut organs weighed by a digital weighing scale (0.01 g, model GF 400, A&D Weighing).…”

“…Dietary protein and amino acids (AAs) levels play a vital role in poultry nutrition to improve growth performance and animal welfare (Zarghi et al 2020a). The efficient utilisation of protein in the diet depends on the amount, composition, and digestibility of dietary AAs (Akbari Moghaddam Kakhki et al 2016).…”

Effect of dietary sulphur amino acid levels and guanidinoacetic acid supplementation on performance, carcase yield and energetic molecular metabolites in broiler chickens fed wheat-soy diets

“…After bleeding, the carcase was obtained by removing, feathers, feet, skin and visceral organs. Weight of the carcase and part (breast, legs and frame defined carcase without the breast and legs) yield and abdominal fat were expressed as a percentage of live body weight (Zarghi et al 2020). In order to measure molecular concentrations of energetic metabolites in heart and breast muscles, about 1 g of heart and breast (1.5 cm deep in the right pectorals tissue) muscle were collected and wrapped in an aluminium foil and kept in À80 C freezer for later (determined ATP, ADP, AMP, PCr and CrN concentration) analysis (Tabatabaei Yazdi et al 2017).…”