The interactive effects of glycine, total sulfur amino acids, and lysine supplementation to corn-soybean meal diets on growth performance and serum uric acid and urea concentrations in broilers

Abstract

Four experiments were conducted to determine the interactive effects of Gly, TSAA, and Lys in corn-soybean meal diets on growth performance of broilers. All experiments were conducted with female Ross x Ross 308 or 708 broilers in brooder batteries from 0 to 18 d posthatching. Treatments had 5 to 8 replications with 5 or 6 broilers per replicate pen. Diets in all experiments were fed without or with Gly (2.32% total Gly + Ser). All diets contained 0.25% l-Lys.HCl except in experiment 1, where no crystalline Lys was added. In experiment 1, the total dietary Lys level was 1.26% with TSAA:Lys of 0.72 and 0.76. Increasing TSAA:Lys increased (P < 0.07) G:F. The main effect of Gly was not significant for ADG, ADFI, or G:F; however, G:F was increased by Gly in broilers fed 0.72 but not in those fed 0.76 TSAA:Lys (Gly x TSAA:Lys, P < 0.03). In experiment 2, the total dietary Lys level was 1.26% with TSAA:Lys of 0.51, 0.68, 0.72, and 0.76. Glycine addition did not affect ADG, ADFI, or G:F; however, increasing TSAA:Lys linearly increased (P < 0.01) ADG, ADFI, and G:F and the response was quadratic for ADG and G:F. Experiment 3 was similar to experiment 2 except the total dietary Lys level was 1.35%. Glycine addition increased (P < 0.03) G:F and decreased (P < 0.04) serum uric acid (SUA) and serum urea N concentrations. Also, increasing TSAA:Lys linearly and quadratically (P < 0.02) increased ADG, ADFI, and G:F. In experiment 4, broilers were fed 2 levels of total dietary Lys (1.26 and 1.35%), 3 levels of TSAA:Lys (0.72, 0.76, and 0.80), and without or with Gly supplementation up to a total of 2.32% Gly + Ser. Glycine addition increased ADG (P < 0.02) and G:F (P < 0.01). The increase in G:F with Gly was not the same for all TSAA:Lys (Gly x TSAA:Lys, P < 0.07). Increasing Lys increased (P < 0.01 to 0.10) ADG, ADFI, and G:F. Glycine addition increased ADG and ADFI more in broilers fed 1.35% Lys than in those fed 1.26% Lys (Lys x Gly, P < 0.09). Glycine addition increased SUA in broilers fed 1.26% Lys but decreased SUA in broilers fed 1.35% Lys (P < 0.01). Glycine addition decreased SUA in broilers fed the TSAA:Lys of 0.80 but not at the other TSAA:Lys (P < 0.08). These data indicate that Gly increased G:F and decreased SUA in diets with 1.35% Lys and excess TSAA.

Response of broilers to gradual dietary protein reduction with or without an adequate glycine plus serine level

“…Alternatively, Gly fortification reduced urea production by inhibiting arginase activity (Austic and Nesheim 1970). Similar to the previous studies (Powell et al 2009;Awad et al 2017;Law et al 2018), we observed a reduction of serum UA content on d 42 with dietary CP reduction by 4.5% or 6%, which could be related to the lower ingestion with the subsequent reduced catabolism of AA (Awad et al 2017;Law et al 2018). Although Gly is directly involved in the synthesis of UA, we did not find an alteration of serum UA content in response to Gly fortification in the low-CP diets, which did not agree with the study of Awad et al (2017).…”

Osmoregulatory function of betaine in alleviating heat stress in poultry

“…Furthermore, improvement in ether extract digestibility has been associated with supplemental glycine in the diet (Han & Thacker, ). Betaine improves the availability of glycine (Eklund et al, ), which conjugates with bile acids synthesized in the liver to form bile salts (Powell, Bidner, & Southern, ). In addition, higher levels of short‐chain fatty acids along the intestinal tract may improve the absorption capacity of the intestinal epithelium, leading to an improved digestive capacity (Butzner et al, ).…”

Effect of Low Protein Diets Supplemented with Glycine on Growth Performance Carcass Traits, Blood Parameters and Antioxidant Status of Mandarah Chicks During Starter and Grower Periods

“…Hilliar et al (2019) showed that reducing crude protein significantly decreased serum uric acid by 26.9%. Moreover, Powel et al (2009) observed that glycine addition to broiler chick diets decreased serum uric acid and serum urea N concentrations.…”

“…Moreover, Awad et al (2018) showed that feeding birds with low protein diet fortified with glycine 0.8 -1% of diets resulted in feed consumption, weight gain and feed conversion ratio equivalent to the broiler chicks fed normal protein diets, as well as improved protein efficiency. In addition, Powel et al (2009) indicated that glycine addition to broiler chick diets increased feed efficiency in diets with 1.35% lysine and excess total sulphur amino acids. Chrystal et al (2020) indicated that inclusions of glycine and threonine in the 16.5% protein diet resulted in 6.18% increase in ileal protein digestibility coefficients and 10.1% increase in ileal protein disappearance rates.…”