Protective Effects Of Glutamine On The Lung Injury Induced By Cold Stress In Chicken

Cold is one of the most universal stressors for animals in cold region. Cold stress, which causes animal slow-growing, poor disease-resistance, even death, can lead to significantly economic loss and restrict the development of northern animal husbandry. Glutamine (Gln) can enhance immunity, and protect tissues from stress, infection, fatigue, oxidation. It has been widely applicated as a feed additive in animal husbandry. The study of anti-stress effect of Gln is less in poultry. Further research of the biochemical metabolism process of Gln in poultry, especially the effect of Gln for maintaining the normal physiological function in stress avian, is necessary.500 yisa chickens were randomly divided into five groups, including control group, stress group, (Gln) low dose group, (Gln) middle dose group, and (Gln) high dose group. Clinical symptoms, postmortem, microstructure and ultrastructure were observed. Degree of lung edema, antioxidative function, inflammatory response, expression of HO-1 and HSP70 mRNA in lung were measured to assess the effect of Gln on the lung injury induced by cold stress in chicken. The results showed as follows:1. Morphology changes were detected by HE staining, transmission electron microscope, which revealed that Gln had good effect on lung injury induced by cold stress in chicken.2. The result of detection on W/D of lung revealed that Gln could relieve the degree of lung edema induced by cold stress, improve the microcirculation of lung, and reduce the pathological injury of lung.3. The result of detection on MDA content, SOD and GSH-Px activity in serum and lung tissue, and DNA crosslinks coefficient in lung cell and protein-carbonyl content in lung tissue revealed that Gln could greatly depress the destruction of oxidation-antioxidant balance induced by cold stress, make the protein-carbonyl content in lung tissue and DNA crosslinks coefficient in lung cell close to normal. It indicated that the antioxidation of Gln plays an important role in reducing the lung injury induced by cold stress in chicken.4. The result of detection on MPO activity and expression of IL-1βand IL-2 mRNA in lung revealed that Gln could inhibit MPO activity and expression of inflammation-stimulating factors, thus exerting protective effect on the lung injury induced by cold stress in chicken.5. The result of detection on concentration of Gln in serum and lung revealed that cold stress could decrease the concentration of Gln in serum and lung. The addition of proper amount of Gln could make the concentration of Gln in serum and lung close to normal, so it was beneficial to adaptive reaction of body.6. The result of TUNEL showed that Gln could inhibit apoptosis of lung cells.7. The expression of HO-1 and HSP70 mRNA were detected by RT-PCR. The result showed that Gln could increase HO-1 and HSP70 mRNA expression. It indicated that Gln could strengthen endogenous protection of body, thus exerting protective effect on the lung injury induced by cold stress.This study revealed that Gln could reduce the lung injury induced by cold stress through the detection on the antioxidative function, inflammatory response and the expression of HO-1 and HSP70 mRNA in lung. It revealed that Gln could reduce the lung injury induced by cold stress in chicken. It provided the scientific theoretical foundation and experimental basis for solving the problem caused by cold stress in animal husbandry.