Study Of Oxidative Stress Model In Broiler Chicks

Two experiments were arranged to evaluate the effect of ACTH, DEX, Ru486 and cortisone onmeat quality, performances, digestion and metabolism, immune function, total antioxidant status ofbroiler chickens firstly. Satellite Cells (SCs) from breast and thigh muscle of broilers were collected andcultured to evaluate the effect of DEX on SCs livability and Ca²⁺ content intracellular. Three kinds ofoxidative stress model were evaluated in this study, which were: acute stress, ACTH and DEX injection;chronic stress: drink cortisone water and cell oxidative stress: DEX was added in culture medium of theSCs. The results indicate that all the three oxidative stress models can induce the change of meat quality,hormone, and SCs livability in broilers.1 Study of acute oxidation stress model in broiler chicksAbstract: The two-hundred and twenty Arbor Acres male broilers, 21 day-old, were used to studythe effect of PSS (Physiological Saline Solution), DEX (Dexamethasone), ACTH (AdrenocortisotropicHormone), and/or R (Ru486, Mifepristone) injection on meat quality. The treatment included: thecontrol group, PSS (1 mL/head), PSS+R, DEX (6mg/kg BW), DEX+R, ACTH (6 IU/kg BW), orACTH+R. Dosage of Ru486 (mifistone) was 50mg/kg BW. The treatments were repeated at 40d. Themain results are shown as follows,The meat qualities were influenced by the injection of ACTH, DEX, and PSS, which include pHvalue reduced, drip loss and shear strength raised. When Ru486 was injection at the same time, theabnormality of the meat quality was mitigated and did not recover to the quality of no injection. The pHvalue, drip loss and shear strength of thigh meat (LM) were all higher than that of the breast meat (BM,P＜0.01). The pH value and drip loss of slaughter at 29-day-old were all higher than that of the 40d(P＜0.01), shear strength were lower than that of the 40d (P＜0.01). The pH value decreased, drip lossand shear strength increased as the time prolonged after injection.The protein and MDA content of the homogenizered tissues (BM, TM, liver and heart) increasedsignificantly, GSH-Px and SOD decreased significantly after the injection of DEX and ACTH. Theabnormalities of tissues were ameliorated when Ru486 was injected at the same time. As the prolongedof the time after hormone treatment, 4h, 8h, 12h and 24h, the redox status of the tissues weredifferenced from tissues. In conclusion, 8h-12h after the injection of ACTH and DEX should be theoptimal time for oxidative stress.The T-AOC, GSH-Px and SOD of blood of DEX and ACTH treatment were all reduced to thelowest, lower than the control group (P＜0.01). The CAT, MDA, CK and AST of blood of DEX andACTH treatment were raised to the highest level and higher than that of the control group (P＜0.01).There were no significant difference between DEX and ACTH treatment on the seven determinedparameters (P＞0.05). The abnormal of blood biological value of the DEX and ACTH treatment were allrejuvenation (P＜0.01) after Ru486 injection at the same time. But the value of T-AOC, MDA, CK andAST of the 3 Ru486 injection treatments were higher than that of the control group (P＜0.01), and GSH-Px, SOD, CAT of the 3 Ru486 injection treatments were lower than that of the control group(P＜0.01). As the prolonged of the time after hormone treatment, 4h, 8h, 12h and 24h, blood T-AOCbecame lower and lower, there have no difference between the value of 8h and 12h (P＞0.05). BloodGSH-Px became lower firstly, 8h and 12h were lower than 4 and 24h (P＜0.05). Blood SOD becamelower also, and the value of 4h and 8h were lower than that of 24h (P＜0.05). Blood CAT, MDA, CKreach the highest level at 8h and then became lower. Blood AST rose to the theist at 12h and 24h. Inconclusion, 8h after the injection of ACTH and DEX should be the optimal time for oxidation stress.Compared to 29d, T-AOC, GSH-Px, SOD, CAT and CK of 40d broiler were lower (P＞0.05), MDA andAST were higher. CAT of 40d was lower and MDA was higher than 29d significantly (P＜0.05). Therewere no deference between 40d and 29d for other parameters.In conclusion, 40 day old birds, 8h after the injection ofACTH (61U/kg BW) or DEX (6mg/kg BW)can be used to model the accurate oxidative stress.2 Study of Chronic Oxidation Stress Model in Broiler ChicksAbstract: The three-hundred and twenty Arbor Acres male broilers, 21 day-old, were used to studythe effect of drinking cortisone water on meat quality. The birds were randomly divided into four groupsby weights, with 8 replicates of each treatment. The treatment included: 0, 10, 20 and 30 mg/L cortisonewater drinking (â… ,â…¡,â…¢andâ…£). Cortisone was applied to the birds via drinking water for 10 d.Feed and water were provided ad libitum. The main results are shown as follows,Drinking cortisone water had little influence on weight gain, feed intake and feed efficiency (F/G)in broilers (P＞0.05), the same results were observed in HDL, LDL. CHO. TG. GRE of blood (P＞0.05).Compared with groups 1, blood TP (P＜0.05) and uric acid (P＜0.01) ofâ…¢andâ…£increasedsignificantly at 10d, and blood AST groupsâ…£increased at 1d (P＜0.05). Compared with control groups,the apparent digestibility of protein and fat of groupsâ…¢andâ…£decreased during 3-4d (P＜0.05), and theapparent digestibility of crude ash of groupsâ…¢andâ…£had decreased significantly during 1-2d and 3-4d(P＜0.05). The results indicated that drink 20-30mg/L cortisone water can be used to simulate thechronic oxidative stress in broilers.Cortisone water drinking had significantly increased meat drop loss of breast and thigh at 6d and10d in broilers (P＜0.01). pH₁ of breast meat was increased significantly of birds that dinked thecortisone water, but pH₁ of the thigh meat had little influenced. Cortisone water drinking had littleincreased pH₂₄ of breast meat, excepted 3d (P＜0.05), but pH₂₄ of thigh meat increased for all thetreatments in broilers (P＜0.05). The relative weight, moisture and protein content of breast and thighmeat did not influenced by the cortisone water drinking (P＞0.05). Compared with the control group, thelipid content of breast meat decreased significantly for all the cortisone treatments at 2d. 6d (P＜0.05).Compared to the control group, the moisture of thigh meat of groupsâ…¢decreased at 6d significantly(P＜0.05), the protein content of thigh meat of groupâ…¡andâ…¢decreased significantly (P＜0.01).Compared with the control group, the lipid content of thigh meat decreased significantly of groupâ…¢at2d, groupsâ…¡andâ…¢at 6d (P＜0.05). The results indicated that drinking cortisone water had little influence on relative weight of meat, but the nutrients content of the meat were influenced significantly(P＜0.05).Compared with control group, blood CS content of groupâ…£increased significantly at 3d, bloodGLU concentration increased significantly at 2d (P<0.05). Compared with the control group, the bloodT₃ and T₄ concentration of groupâ…£increased obviously at 2d and 3d respectively (P＜0.05). Comparedwith contrast group, blood MDA content of groupâ…£increased significantly at 1-3d and 6d respectively(P＜0.05), blood SOD and GSH-Px activity of groupâ…£decreased significantly at ld and3d (P＜0.05),T-AOC activity of groupâ…£decreased at 2d (P＜0.05), CK activity of groupâ…£increased at 6d (P＜0.05).The results indicated thatâ…£group had successfully induced oxidative stress.The relative weights of heart, liver, thymus and bursa of Fabricius were not influenced by thecortisone water drinking (P＞0.05), but the relative weight of spleens was increased at 2d (P＜0.05). Theabdominal fat and liver moisture did not influenced by the cortisone water drinking (P＞0.05) also.However, the lipid content of the liver was increased significantly at 10d of cortisone water drinking(P＜0.01). The MDA content of the heart was increased at 2-3d and decreased at 10d significantly(P＜0.01), the GSH-Px content was increased at 1 d (P＜0.01), the SOD content decreased significantly atld (P＜0.05). The MDA content of the liver was increased at 2-3d significantly (P＜0.01), the GSH-Pxand SOD activity was significantly decreased throughout the test period except 6d (P＜0.01). The resultsindicated that chronic oxidative stress had little influence on develop of the immune organs in broilers,but the peroxidative status of tissues were significantly Influenced.3 Study of Oxidation Stress Model in satellite cells from Broiler ChicksThe effect of DEX on SCs morphology and number of living SCs was observed under microscope,detected by means of MTT assay, by nitro blue tetrazolium (NBT) reduction test, and MDA detection.Then the oxidant model was verified by vitamin C addition. The main results are shown as follows,With the increasing of DEX concentration in the medium, the lively SCs were decreased markedly,and when DEX concentration was higher than 0.625g/L in the medium, there few lively SCs were seenin the microscope. The numbers of lively SCs from thigh muscle were higher than that of SCs frombreast muscle at the same DEX concentration.With the increasing of DEX concentration in the medium, number of lively SCs decreasedsignificantly and Trypan blue staining rate of SCs increased significantly. The function relation modelbetween the two parameter should be: Y (numbers of lively SCs,×10⁴) =35.186e^-0.7821X; Y (Trypan bluestaining rate of SCs, mortality,ï¼…)=44.039X^-0.3492;The relative livability of SCs from breast and thigh muscle was influenced by the added DEX inthe medium significantly. The function relation model between DEX concentration (X, g/L) and relativelivability of SCs (Y,ï¼…) should be: for BM, DEX: y=14.944X^-0.6082; DEX+VC: y=19.642X^-0.4663; for TM:DEX: y=17.091X^-0.5193; DEX+VC: y=40.418X^-0.2536.Lipid peroxidation on the membrane of SCs was enhanced by the added DEX in the medium. Thefunction relation model between DEX concentration(X, g/L) and relative MDA producing of SCs (Y,ï¼…) should be: for BM: Y=1.5723x^0.0983; TM: Y=1.3213x^0.0789.DEX in the medium accelerated the reduction of NBT; the rate of photochemical acceleration wasconnected with the concentration of DEX. With the increasing of DEX concentration in the medium, therectified absorbency of NBT was increased markedly. The function relation model between DEXconcentration (X, g/L) and rectified absorbency of NBT should be: for BM: Y=0.832gx^0.457; and for TM:y=0.3898x^0.334.The livability of SCs was improved since VC was added in the medium, and the improvementbecame lower as the increasing of DEX concentration. The function relation model between DEXconcentration(X, g/L) and the livability of SCs (Y) should be: for VC:Y=1.5451x^0.1007; VC+DEX:Y=1.3099x^0.0685. In conclusion, we can establish the oxidant stress model through added DEX in themedium of SCs. This model would be used to develop additives to improve the meat quality.4 Effect of DEX treatment on Ca²⁺ content in the satellite cell from broiler muscleAbstract: The effect of glucocorticoid (GC) on Ca²⁺ content of satellite cells (SCs) from broilermuscle was determined to confirm if GC can activities Ca²⁺ signal transmit system in the muscle cells.The SCs were picked up from leg and breast muscle of day-old Abor Acres broilers respectively, andcultured in DMEM culture medium which content 20ï¼…FBS. After 2 days' cultured the SCs was markerwith Fluo-3/AM. Using laser scanning confocal microscope (LEICA TCS SP2 SE) and highly sensitiveCa²⁺ fluorescent dye, Fluo-3/AM, we measured the kinetic changes of Ca²⁺ in single intact living SCs,before and after Dexamethasone (DEX) directly treatment. The results showed that:Intraceilular Ca²⁺ content reduced as DEX concentration reduced. The max value of intracellularCa²⁺ content of SCs from breast muscle and thigh muscle was 144, 80, 63 and 66, 60, 48 for treatment10^-4, 10^-5 and 10^-6 mol/L DEX respectively. The time consumed to reach the max value became longer asDEX concentration reduced, for treatment 10^-4, 10^-5 and 10^-6 mol/L DEX, SCs from breast muscle andthigh muscle was 59s, 130s, 158s and 80s, 98s, 216s respectively. The SCs need more time to go downto the stillness level DEX concentration reduced, for treatment 10^-4, 10^-5 and 10^-6 mol/L DEX, SCs frombreast muscle and thigh muscle was 542s, 389s, 606s and 260s, 675s, 533s respectively. Compared tothe SCs from leg muscle, the SCs from breast muscle were more sensitive to DEX treatment. DEX at10^-4-10^-6 mol/L can enhance the intracellular Ca²⁺ content. These results indicate that extra cellular DEXcan enhance intracellular Ca²⁺ content through activize Ca²⁺ signal transmit system in the muscle cellsfrom broiler.