Dietary L-citrulline supplementation modulates nitric oxide synthesis and anti-oxidant status of laying hens during summer season

Abstract

Background L-citrulline (L-Cit), a non-protein amino acid, has been implicated in several physiological functions including anti-inflammatory, anti-oxidative, and hypothermic roles, however, there is a paucity of information with regards to its potential in poultry production. Methods This study was designed to investigate the effects of dietary L-Cit supplementation on the production performance, nitric oxide production, and antioxidant status of laying hens during summer period. Hy-Line Brown laying hens (n = 288, 34 weeks old) were allotted to four treatment, 6 replicates of 12 chickens each. Dietary treatments of control (basal diets), 0.25%, 0.50% and 1.00% L-Cit supplementation were fed to chickens for eight (8) weeks. Production performance, free amino acid profiles, nitric oxide production, and antioxidant properties were measured. Blood samples were collected at the 4th and 8th weeks of the experiment. Results Air temperature monitoring indicated an average daily minimum and maximum temperatures of 25.02 °C and 31.01 °C respectively. Dietary supplementation with L-Cit did not influence (P > 0.05) the production performance, and rectal temperature of laying hens. Egg shape index was increased (P < 0.05) with increasing levels of L-Cit. Serum-free content of arginine, citrulline, ornithine, tryptophan, histidine, GABA, and cystathionine were elevated, but taurine declined with L-Cit diets. Plasma nitric oxide (NOx) concentration was highest at 1% L-Cit. Likewise, nitric oxide synthase (NOS) activity for total NOS (tNOS) and inducible NOS (iNOS) were upregulated with increasing L-Cit levels, although, tNOS was not affected at the 4th week. Anti-oxidant enzymes including catalase and superoxide dismutase (SOD) were increased with L-Cit supplementation, however, SOD activity was unchanged at 4th week, while total anti-oxidant capacity increased at the 8th week. L-Cit supplementation attenuated the extent of lipid peroxidation, and also inhibited glutathione peroxidase activity. Conclusion Dietary L-Cit supplementation modulated systemic arginine metabolism, nitric oxide synthesis, antioxidant defense system, and increased the egg shape index of laying hens during the summer season. 1% L-Cit supplementation proved most effective in potentiating these effects and may be adopted for feed formulation strategies.

Response of laying hens to L-arginine, L-citrulline and guanidinoacetic acid supplementation in reduced protein diet

“…It has been suggested that diurnal fluctuating temperatures have minor effects on laying hen performance compared to constant high temperatures. Hens are able to tolerate to short term increases daily temperatures with little impact on production ( Al-Saffar and Rose, 2002 ; Uyanga et al, 2020 ). The overall laying performance in the current study from wk 20 to 39 in hens fed the SP treatment, were similar to Hy-Line standards ( Hy-Line International, 2016 ).…”

Potential Implications of Citrulline and Quercetin on Gut Functioning of Monogastric Animals and Humans: A Comprehensive Review

“…This catabolism engulfs about 40% of the luminal arginine in adult rats, 38% of dietary arginine in adult humans [39], and ~70% in mice with limited quantities entering into peripheral circulation [42], suggesting that significant quantities of supplemental arginine are unavailable to extra-intestinal tissues [39]. Additionally, exogenous L-citrulline administration elevated serum-free contents of amino acids including arginine, citrulline, and ornithine in a dose-dependent manner [43].…”

“…(b) Nitric oxide regulation L-citrulline, as a functional amino acid with biological functions including cellular metabolism and organ function [37], is also an efficient precursor for NO synthesis [43]. NO is involved in multiple physiological processes in the GIT, particularly the regulation of gastrointestinal motility, gastroprotection, and mucosal blood flow [35].…”

“…Citrulline has been widely known for its antioxidant properties, which has been attributed either to the direct effects of citrulline and/or indirect effects via NO production [160,172]. Citrulline directly mediated antioxidant defense by influencing the enzyme activities of catalase, superoxide dismutase (SOD), and the total antioxidant capacity, but decreased MDA contents, abolishing the degree of lipid peroxidation [43]. L-citrulline was shown to protect the gastric mucosa during ethanol-induced oxidative stress by recovering SOD, and GSH-Px activities approximately to the control levels [19].…”

Ultra-Performance Liquid Chromatography-Mass Spectrometry-Based Untargeted Metabolomics Reveals the Key Potential Biomarkers for Castor Meal-Induced Enteritis in Juvenile Hybrid Grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂)

“…The available information regarding the use of citrulline in animals is very limited; nevertheless, it is slightly gaining research interest as a result of its unique metabolism. Citrulline not only serve as functional marker for gut barrier dysfunction, but it has been associated also with several intestinal diseases, including short bowel syndrome, necrotizing enterocolitis and gastric ulcers ( 119 ). The observed increase in Citrulline metabolite intensity might have been due to the increased arginine content analysed ( Supplementary Table 1 ) in the CM ingredient, which was higher than observed in the FM.…”