Digestible tryptophan requirements of meat quails in the growth phase

Abstract

-The objective of this experiment was to estimate the digestible tryptophan (DTrp) requirements for growing meat quails. In the first experiment (1-14 days of age), 1,950 quails were distributed in a completely randomized design, with six levels of DTrp (0.27; 0.30; 0.33; 0.36; 0.39 and 0.42% of diet), five replications and 65 quails per experimental unit.There was a linear increase of feed intake, tryptophan intake, weight gain and body weight with the DTrp levels increase. In the second experiment (15-35 days of age), 1,350 quails were distributed in a completely randomized design, with six levels of DTrp (0.22; 0.25; 0.28; 0.31; 0.34 and 0.37% of diet), five replications and 45 quails per experimental unit. There was a linear increase for tryptophan intake, carcass yield, ash levels and protein deposition rate with the DTrp levels increase.In the third experiment (28-35 days of age), conducted to determine the nitrogen balance, 150 males were housed in galvanized wire cages featuring drinker, feeder and individual metal tray lined with plastic to collect the excreta. The design was completely randomized, with six levels of DTrp (0.22; 0.25; 0.28; 0.31; 0.34 and 0.37% of diet), five replicates and five quails per experimental unit. Linear decrease was observed on the nitrogen balance and metabolization coefficient with the DTrp levels increase. The nutritional requirement of digestible tryptophan for maximum growing of meat quail, in the period from 1 to 14 days of age, is higher or equal to 0.42%; in the period from 15 to 35 days, it is 0.22%.

Does the metabolizable energy influence the performance, carcass characteristics and biochemical parameters of European quails from 28 to 42 days of age?

“…(2012) found no differences for meat cuts of male laying quail linings fed with energy levels between 2600 to 3000 kcal/kg, for dry matter, crude protein and mineral matter. However, these authors observed differences in the ether extract content, as well as Ton et al (2011) who reported an increase in the content of ether extract, with an increase in the levels of metabolizable energy (2800−3100 kcal/kg), which did not occur in this study.…”

“…Although, breast yield was affected by the level of ME, indicating that the increase in the levels of ME in the diet provided a reduction in breast yield, with greater deposition of fat in the muscle and its loss in the evisceration process. According to Griep Júnior et al (2017), surplus energy is stored as fat in the carcass, mainly in the breast.Although birds deposit more fat on the ends of the muscle pectoralis major and in the viscera, part of this fat is also directed to the deposition between muscle fibres, important for meat tenderness, as reported in the texture analysis Ton et al (2011). found no significant effect of the metabolizable energy in relation to the weight and yield of the breast in beef quails in the 4-to-35-day phase fed with different energy levels (2800, 2900, 3000, 3100 kcal/kg of feed).…”

“…Research has shown that diets with 3100 kcal of ME/kg can reduce the feed intake of quails by up to 7% (Ton et al, 2011).…”

Tryptophan in poultry nutrition: Impacts and mechanisms of action

“…Trp also contributes as a precursor to the production of the co-enzyme nicotinamide adenine dinucleotide and its phosphorylated form, which are induced to recycle antioxidant enzymes such as glutathione peroxidase and catalase (Agledal et al, 2010;Sainio et al, 1996;Xiao et al, 2018). In addition, the meat yield and dressing percentage increase with the added Trp levels (Corzo et al, 2005;Denbow et al, 1993;Kerr et al, 2005;Khanipour et al, 2019;Wei et al, 2011), possibly due to enhanced protein deposition (Fatufe et al, 2005;Ton et al, 2012) as a consequence of the stimulated secretion of insulin-like growth factor Ι. Insulin-like growth factor Ι promotes the utilization of amino acids and glucose, thereby leading to enhanced protein anabolism and reduced protein degradation via downregulation of the mRNA expression levels of cathepsin B and 20S protease (Duclos et al, 1993;McMurtry, 1998;Pan et al, 2013). Corticosterone suppresses protein synthesis and increases the breakdown of proteins (Dong et al, 2007;Hayashi et al, 1994).…”

Optimum Digestible Valine to Lysine Ratio for Meat-Type Quails from 15 to 35 Days of Age

“…methionine + cysteine, threonine and tryptophan for meat-type quails from 15 to 35 d of age have been widely studied (Scherer et al, 2009;Ton et al, 2012;Ton et al, 2013;Ribeiro, 2015). Valine is considered the 4 th limiting amino acid in corn and soybean meal-based diets for broilers (Corzo et al, 2007;Rostagno et al, 2011).…”