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

Effect of dietary glycine supplementation on productive performance, egg quality, stress response, and fatty liver incidence in laying hens raised under heat stress conditions

The current experiment aimed to investigate the effect of dietary glycine (Gly) supplementation on productive performance, egg quality, stress response, and fatty liver incidence in laying hens raised under heat stress (HS) conditions. A total of two hundred eighty 24-wk-old Lohmann Brown-Lite laying hens were randomly allotted to 1 of 4 dietary treatments with 7 replicates. The negative control (NC) diet was prepared to meet or exceed the nutrient and energy requirement for Lohmann Brown laying hens, whereas the positive control (PC) diet was formulated to increase AMEn by 100 kcal/kg compared with the NC diet. Two additional diets were prepared by supplementing 0.341% and 0.683% Gly to the NC diet. All hens were exposed to cyclic HS at 31.4 ± 1.17°C for 8 h/d and 26.7 ± 1.10°C for the remaining time for a 12-wk trial. Results indicated that increasing supplementation of Gly in diets tended (linear, P = 0.088) to decrease the FCR of laying hens. Increasing supplementation of Gly in diets increased (linear, P < 0.05) eggshell lightness and decreased (linear, P < 0.05) egg yolk color. Moreover, a tendency for a quadratic association (P < 0.10) of serum aspartate aminotransferase and alanine aminotransferase concentrations with increasing supplementation of Gly was observed. Increasing supplementation of Gly in diets decreased (linear, P < 0.05) blood heterophil:lymphocyte ratio of laying hens. Hens fed the NC diet showed higher fatty liver incidence (P < 0.05) than those fed the PC diet, but increasing supplementation of Gly decreased (linear, P < 0.05) fatty liver incidence of laying hens. In conclusion, increasing supplementation of Gly up to 0.683% in diets decreases FCR, stress response, and fatty liver incidence in laying hens raised under HS conditions.

Betaine as an alternative feed additive to choline and its effect on performance, blood parameters, and egg quality in laying hens rations

This research aimed to evaluate how using betaine levels as a choline substitute affects productive performance, egg quality parameters, fatty acids profile, and antioxidant status in laying hens. One hundred and forty brown chickens, 45 wk old, were divided into 4 groups, each group of 7 replicates with 5 chickens per replicate. The first group of diets with choline has control (A) 100% choline, the second group (B) 75% choline + 25% betaine, the third group (C) 50% choline + 50% betaine, and the fourth group (D) received 100% betaine. No significant effects were observed in final body weight (BW), body weight gain (BWG), egg production (EW), and feed intake (FI) for laying hens. In the diet in which betaine was replaced choline, egg mass (EM) and egg weight (EW) increased compared to the control group (P < 0.05). Also, after 12 wk of feeding, the egg quality parameters were not influenced; however, yolk color was increased significantly compared with the control group. Serum total cholesterol, LDL-lipoprotein, HDL-lipoprotein, triglyceride, glucose, aspartate transaminase (AST), and alanine transaminase (ALT) were not affected by replacing choline with betaine. Furthermore, liver malondialdehyde (MDA) content, yolk vitamin E, and fatty acid levels were not significantly affected by replacing choline with betaine. Moreover, hens fed betaine displayed an increased antibody titer of the Newcastle disease (ND) virus. EW and EM were increased by 3.50% and 5.43% in 100% betaine group (D) when compared to the control group. Isthmus weight was decreased by 48.28 % in 50% choline + 50% betaine group (C) when compared to the control group. ND was increased by 26.24% in 100% betaine group when compared to the control group. In conclusion, betaine supplementation positively affected productive performance, egg quality measurements, and immunity response in Bovans brown laying hens.

Influence of increasing glycine concentrations in reduced crude protein diets fed to broilers from 0 to 48 days

Two experiments investigated broiler growth performance and processing characteristics when fed increasing Gly concentrations in reduced CP diets fed from 0 to 48 d. In experiment 1, birds were allocated to 1 of 4 dietary treatments: a control (CTL) diet containing feed-grade L-Met, L-Lys, and L-Thr, a reduced CP (RCP) diet with additions of feed-grade L-Val and L-Ile, or the RCP diet with moderate (M Gly) or high Gly (H Gly) inclusion levels to achieve a total Gly + Ser of 100 or 112%, respectively, of the CTL diet. Birds in experiment 2 were assigned to 1 of 6 dietary treatments: a CTL diet, a RCP diet, or a low CP (LCP) diet without or with added Gly to achieve 88, 100, 112, or 124% total Gly + Ser concentrations of the RCP diet. For experiment 1, 0 to 14 d broiler performance was similar (P > 0.05) among dietary treatments. From 0 to 48 d, broilers fed the H Gly diet had the lowest (P = 0.006) body weight gain (BWG) and highest (P = 0.003) feed conversion ratio (FCR). Feeding either the RCP or M Gly diet resulted in similar (P > 0.05) growth and processing characteristics to the CTL. For experiment 2, increasing Gly levels in the LCP diet linearly reduced (P ≤ 0.027) 0 to 14 d FI and FCR. From 0 to 48 d, broilers had similar (P > 0.05) performance when fed the CTL or RCP diet, but had a higher (P < 0.001) FCR when fed the LCP88 diet. Increasing Gly levels linearly reduced (P = 0.033) FCR. Total breast meat yield was negatively affected (P ≤ 0.020) when feeding the LCP88 diet and did not respond to Gly levels. In conclusion, effects of increasing total Gly + Ser levels on 0 to 48 d broiler performance are likely dependent on the content of dietary CP and other potentially interacting nutrients.

Effect of crude protein reduction in blood, performance, immunological, and intestinal histological parameters of broiler chickens

We aimed to evaluate the effects of the reduction in dietary crude protein (CP) on blood urea, uric acid, performance, immunity, and intestinal histology of broilers. Four diets were formulated with 22.50%, 21.50%, 20.50%, and 19.50% of CP (1 to 21 days) and 19.20%, 18.20%, 17.20%, and 16.20% of CP (22 to 42 days), meeting the requirements of essential amino acids in all diets. A total of 800 male Ross chicks were randomly allocated to 32 pens, with 25 birds each (n = 8). Blood and intestines had been collected for analysis. Uric acid decreased and urea increased with the reduction of CP (p < 0.05). Reduction in performance and intestinal parameters (villus, crypt, and goblet cells) was observed with the reduction of CP (p < 0.05). Lower levels of CP resulted in alteration (p < 0.05) in CD4 and CD8 lineages (21 and 42 days). Broken-line models estimated (p < 0.05) the CP requirement for growth between 21% and 21.3% (1 to 21 days) and between 17.2% and 17.4% (22 to 42 days) and CP requirements between 17.2% and 18.2% for maximum response of immune cells (42 days). Reduction in dietary CP has a negative impact on performance, immune response, and intestinal histology of broilers, even with adequate levels of essential amino acids.

Dietary glycine equivalent and standardized ileal digestible methionine + cysteine levels for male broiler chickens fed low-crude-protein diets

This study was conducted to determine the optimum dietary glycine equivalent (Glyequi) level in low-crude-protein diets of 181 g·kg−1 containing varied concentrations of standardized ileal digestible (SID) methionine + cysteine (Met + Cys) for broiler chicks (1–21 d old). A total of 1275, 1-d-old Cobb-Vantress® male broilers were distributed in a 5 × 3 factorial arrangement with a completely randomized design of 15 treatments with five replicates of 17 birds each. Treatments consisted of five levels of dietary Glyequi (14.9, 16.4, 17.9, 19.4, and 20.6 g·kg−1) and three concentrations of SID Met + Cys (7.70, 9.0, and 10.3 g·kg−1). Interactions between Glyequi and SID Met + Cys levels were observed for feed:gain (P = 0.055) and breast meat yield (BMY) (P = 0.017). In 7.7 and 9.0 g SID Met + Cys·kg−1 diets, optimal feed:gain and increased BMY were observed at Glyequi levels not lower than 17.9 g·kg−1. In 10.3 g SID Met + Cys·kg−1 diet, a lower feed:gain was achieved at 19.4 g Glyequi·kg−1. Therefore, a minimum dietary level of 17.9 g Glyequi·kg−1 is needed to increase growth of broilers fed diets containing 7.7 or 9.0 g·kg−1 SID Met + Cys, whereas 19.4 g·kg−1 Glyequi is necessary in diets containing 10.3 g·kg−1 SID Met + Cys for optimum growth.

Amino acid requirements for laying hens: a comprehensive review

The main aim of this review is to consolidate the relevant published data examining amino acid requirements of layer hens and to reach a new set of recommendation based on these data. There are inconsistences in lysine, sulphur-containing amino acids, threonine, tryptophan, branched-chain amino acids, and arginine recommendations in data that have surfaced since 1994. This review finds that breed, age, basal diet composition, and assessment method have contributed toward inconsistencies in amino acid recommendations. Presently, the development of reduced-protein diets for layer hens is receiving increasing attention because of the demand for sustainable production. This involves quite radical changes in diet composition with inclusions of nonbound, essential and nonessential amino acids. Increasing inclusions of nonbound amino acids into layer diets modifies protein digestive dynamics, and it may influence amino acid requirements in layer hens. This review considers present amino acid recommendations for layer hens and proposes refinements that may better serve the needs of the layer industry in the future.

Osmoregulatory function of betaine in alleviating heat stress in poultry

This review focuses on the osmoregulatory function of betaine and its effect in terms of alleviating heat stress in poultry. Poultry appear to be particularly sensitive to temperature-associated environmental challenges, especially heat stress. High ambient temperatures are deleterious to productive performance in poultry, including broilers, laying hens, quails and turkeys, resulting in considerable economic losses. Heat stress impairs overall poultry production by decreasing feed intake and negatively affecting intestinal development, leading to reduced nutrient digestibility. Apart from inducing a high mortality rate, heat stress is known to depress growth rate and reduce meat yield in broilers. In layers, lower feed intake impairs ovarian function, leading to decreased feed efficiency, egg production and egg quality. In addition, reduced immune functions, such as thyroid activity and antibody production, are evident in poultry exposed to heat stress. Heat stress increases the production of oxidants, causing oxidative stress and lipid peroxidation of cell membranes. Poultry respond physiologically and behaviourally when encountering the negative effects of heat stress, attempting to return the body to homeostasis. This requires energy at the expense of weight gain or egg production. Due to its zwitterionic structure, betaine has osmoprotective properties that aid in protecting intestinal cell proteins and enzymes from environmental stress, including high ambient temperature, thereby counteracting performance losses. Betaine also exerts an osmoregulatory role in cells, regulating water balance, and this results in more stable tissue metabolism. Inclusion of betaine in the diet may be beneficial for alleviating physical reactions to heat stress, as indicated by increases in nutrient digestibility. In broilers, betaine supplementation increases weight gain and breast muscle yield, while improving feed conversion. In layers, betaine supplementation improves egg production, egg quality traits and immune indices. In conclusion, due to its osmoregulatory functions, betaine plays an important role in alleviating heat stress in poultry.

Effect of total sulfur amino acids in corn - cassava - soybean diets on growth performance, carcass yield and blood chemical profile of male broiler chickens from 1 to 42 days of age

The experiment was conducted to determine the effects of total sulfur amino acid (TSAA) in diets on growth performance, carcass yield and blood chemical profile of commercial male broiler chickens from 1 to 42 days of age. Six graded levels of TSAA were fed during the starter (1–21 days of age) and the grower (22–42 days of age) periods at 61, 84, 100, 105, 110 and 115% of commercial recommendation. The experiment was a completely randomised design. In all, 1050 commercial male broiler chicks (Ross 308) were divided into six treatments, and each treatment consisted of seven replicates of 25 chicks each. Bodyweight gains of chicks that received TSAA at 100% of commercial concentrations were significantly greater than those that received the recommended National Research Council concentrations (84% of commercial levels, P < 0.05). The best feed-conversion ratio and feed cost per gain were found at the commercial recommendation level. Nonetheless, broilers that were fed TSAA at concentrations higher than the commercial recommendation levels did not exhibit positive effects on growth performance. With respect to carcass yield, the breast meat yield was increased by increasing TSAA in the diets (P < 0.05), particularly when supplied at commercial recommendation levels, whereas the eviscerated carcass and liver weights were not significantly affected. There was no significant effect of increasing TSAA in the diets on serum triglyceride, uric acid, total protein, albumin and globulin. In conclusion, broilers fed diets supplemented with TSAA at commercial concentrations gave the best growth performance, carcass yields and economic return.