Effect of chronic immobilization stress on growth and plasma lipid composition in young broiler chicken
M. SIRAJUDEEN, JAGMOHAN, JAGBIR SINGH TYAGI, AND K.V.H. SASTRY
Division of Physiology and Reproduction
Central Avian Research Institute, Izatnagar - 243122
Day old unsexed broiler chicks (n=90) were raised under standard managemental conditions with ad-lib provision of feed and water. After 8 weeks, 50 birds were randomly distributed into three experimental groups. Group A served as control, group B and C were subjected to immobilization stress for 30 min. and 2 hour respectively. Daily feed intake and body weight gain in all the birds were monitored for 7 weeks. After 21 days of trial plasma lipid components were analyzed in all the groups. It was observed that throughout the experimental period stressed birds (group B and C) consumed significantly (P<0.5) less feed as compared to unstressed control birds (groups A). Between groups B and C, group B birds had higher feed intake than group C, however this difference narrowed down as the trial progressed. Mean body weight gain was significantly (P<0.5) higher in-group A than either of the other two groups. This immobilization stress induced suppression of body growth was more severe and pronounced in-group C than in-group B especially towards the later stages of the study. After 21 days of stress enforcement, assay of blood plasma for lipid constituents like total cholesterol, phospholipids, triglycerides did not reveal significant differences between the groups. However, in-group C a significant (P<0.5) decline in plasma HDL- cholesterol was noticed when compared to group B and A (94.07mg Vs 119.76mg and 124.96mg). Group B did not differ significantly from group A in either HDL-or LDL- cholesterol concentration (100.59mgVs 103.0mg). Interestingly group C had significantly (P<0.5) elevated plasma levels of LDL-cholesterol when compared to group A (121.68mg Vs103.3mg). From the above study, it can be concluded that immobilization stress when applied repetitively for chronic duration caused a dose-dependent suppression of feed intake and body growth in young broiler chicken. Further, immobilization stress altered the critical balance between HDL-and LDL- cholesterol unfavorably without affecting the total plasma lipid concentration.