Supplementation with glutamine(Gln) has beneficial effects on intestinal and immune functions. Cage-reared chicks suffer from various stressors during early growth, but the effect of Gln supplementation on growth performance and stress hormones is uncertain. We investigated the effect of Gln on growth performance and blood corticosterone levels in Hyline chicks. Groups of 3-day-old chicks were fed one of three diets: normal feed(CTL group), normal feed supplemented with a low level of Gln, or normal feed supplemented with a high level of Gln. Growth and various physiological and biochemical parameters related to stress were assessed. On day 30, after a 24-h fast, blood was analyzed for corticosterone and other parameters, including glutamic oxaloacetic transaminase, gamma-glutamyl transpeptidase, total bilirubin, lactate dehydrogenase, total cholesterol, high-density lipoprotein cholesterol, blood urea nitrogen, blood total protein, and inorganic phosphate. Growth performance was maintained in Gln supplemented groups. The corticosterone level was decreased in the two groups receiving Gln supplementation compared to the CTL, and all other humoral factors did not differ between the groups. We suggest that Gln supplementation is a safe and useful strategy for reducing the effects of stress in cage-reared chicks.

ABSTRACT
 Introduction
 Materials and Methods
  1 Animals and their care
  2 Experimental design
  3 Biochemical analyses of blood
  4 Glutamine synthetase activity assay
  5 Western blot analysis
  6 Enzyme-linked immunosorbent assay(EIA) of plasmacorticosterone
  7 Hematoxylin and eosin stain
  8 Statistics
 Results
  1 Effects of Gln supplement on growth and bloodcorticosterone
  2 Effects of Gln-supplementation on liver and brain tissues
  3 Effects of Gln-supplementation on aspects of physiology
 Discussion
 Acknowledgement
 References

• Minhee Kim(Department of Anatomy and Convergence Medical Science, Bio Anti-Aging Medical Research Center, Institute of Health Sciences, Gyeongsang National University Medical School, Gyeongsangnam-do Livestock Veterinary Research Institute)
• Soonwoong Jung(Department of Anatomy and Convergence Medical Science, Bio Anti-Aging Medical Research Center, Institute of Health Sciences, Gyeongsang National University Medical School)
• Hyeonwi Son(Department of Anatomy and Convergence Medical Science, Bio Anti-Aging Medical Research Center, Institute of Health Sciences, Gyeongsang National University Medical School)
• Hyun Joon Kim(Department of Anatomy and Convergence Medical Science, Bio Anti-Aging Medical Research Center, Institute of Health Sciences, Gyeongsang National University Medical School) Corresponding author