Browsing by Author "Srinivas Reddy, Bellur"
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ThesisItem Open Access Effect of induced stress and antistress agents on the physiological parameters in broiler chicken(Department of Physiology, College of Veterinary and Animal Sciences, Mannuthy, 2003) Srinivas Reddy, Bellur; KAU; Philomina, P TIn modern poultry production system various factors namely floor space reduction, feed and water restriction, high environmental temperature, vaccination, medication, debeaking etc. have the potential to induce stress in poultry which results in poor performance as well as reduction in immune response as the nutrients normally utilized for growth and production are diverted to counteract the stress and survival. The study was undertaken with the objective of evaluating the influence of induced stress and anti stress agents (dietary ascorbic acid and Zeetress®) on various physiological, biochemical and production parameters in broiler chicken. Fifty six numbers of day old broiler chicks (Vencob) procured from a commercial hatchery were reared in battery cages under the standard managemental conditions upto four weeks of age. Then they were randomly selected and divided into seven groups (G-I to G- VII) with eight birds per group. The birds in different groups were as follows: G-I as the control, G-II as floor space reduced group (33%), G-III as floor space reduced group supplemented with Zeetress® @ 0.01%, G-IV as floor space reduced group supplemented with ascorbic acid @ 0.02%, G- V as 30% feed restriction, G- VI as 30% feed restriction with dietary supplementation of Zeetress® @ 0.0 I % and G- VII as 30% feed restriction with dietary supplementation of ascorbic acid @ 0.02%. The birds were maintained in battery cages under standard managemental conditions on broiler ration with the exception of floor space reduction, feed restriction and incorporation of dietary anti stress agents. Production parameters such as weekly weight gain and feed efficiency were analyzed on weekly basis. Blood was collected with suitable anticoagulants, initially at fourth and then at sixth and eighth week of age. Whole blood was utilized for analysis of haematological parameters, heterophil: lyrnphocyte (H:L) ratio and mitogen induced lymphocyte proliferation test. Plasma was utilized for biochemical analyses i.e. for protein profile, lipid profile and estimation of glucose, uric acid and cortisol. The data were statistically analysed by appropriate tests. The birds of G- V group showed significantly lower values of TEC, Hb, VPRC and TLC at sixth and eight week of age. The dietary supplementation of Zeetress® and ascorbic acid in floor space reduced groups feed restricted groups did not show any significant influence on the values of TEC, Hb, VPRC, ESR, TLC when compared to the birds of respective stress induced groups G-II and G- V. The birds of stress induced groups G-II and G- V had lower lymphocyte count and higher heterophil and basophil count, higher H:L ratio and suppressed mitogen induced lyrnphocyte proliferation (probably due to a rise in level of plasma corticosteroids as a result of stress response) when compared to birds of G-J group, both at sixth and eighth week of age. Dietary supplementation of Zeetress® and ascorbic acid in floor space reduced groups and feed restricted groups elevated the lymphocyte counts, suppressed heterophil and" basophil counts, H:L ratio and considerably improved the mitogen induced lymphoblastogenic response both at sixth and eighth week of age. In the present study the birds of G-II and G- V group had no significant variation in plasma protein profile and glucose levels but had increased plasma concentration of ortisol (probably due to stress induced adrenal hyper activity) and decreased uric acid, when compared to birds of control group G-I, both at sixth and eighth week of age. Dietary Zeetress® and ascorbic acid supplementation in floor space reduced groups and feed restricted groups showed a lower plasma concentration of cortisol both at sixth and eighth week of age, and significantly increased uric acid at eighth week of age. Dietary supplementation of Zeetress® and ascorbic acid in floor space reduced groups decreased plasma concentration of cholesterol both at sixth and eighth week of age and total lipids at sixth week of age. In birds of feed restricted G- V group plasma concentration of cholesterol, triglycerides and total lipids were lower both at sixth and eighth week of age when compared to birds of control group G-I. The dietary supplementation of Zeetress® and ascorbic acid in feed restricted groups had no significant influence on plasma concentration of cholesterol both at sixth and eighth week of age. However, there was an increased concentration of triglycerides both at sixth and eighth week of age with significant increase in total lipids at eighth week of age, when compared to birds of G- V group. There was no significant variation In body weight and weight gain of birds in all floor space reduced groups compared to birds of control group (G-I) at all weeks of age with the exception of lower weight gain in G-IJI and G-IV when compared to G-II at eighth week of age. The body weight and weight gain in the birds of all feed restricted groups were lower when compared to birds of control group (0-1), at all weeks of age. A perusal of the overall feed efficiency from 5 to 8 weeks of age revealed that the birds of 0- VI group supplemented with Zeetress® recorded a superior FE (2.22) whereas an inferior value of 2.59 was noted in 0- V group without any dietary antistress agent. The control group recorded a FE of 2.29. Zeetress® supplementation improved overall FE in feed restricted group (0- VI). On the other hand this advantage was not observed in floor space reduced group (O-IlI). Dietary ascorbic acid improved overall FE only in case of feed restricted group 0- VII when compared to that of 0- V group. However, in floor space reduced group (O-IV), ascorbic acid supplementation could not improve the FE. The observations of the present study revealed that both feed restriction and floor space reduction resulted in some sort of chronic stress which led to variation in haematological and biochemical parameters, and impaired growth (in feed restricted groups). Analysis of TLC, OLC, mitogen induced Iymphocyte blastogenic response and plasma cortisol values indicated that there was a marked level of immunosuppression in the stressed birds. The magnitude of variation in most of these parameters was higher at sixth week of age when compared to that of eighth week values indicating some sort of habituation/ adaptation occurred upon chronic stress in the broiler chicken. The antistress agents - Zeetress® and ascorbic acid were equally effective in reversal of stress induced alterations in haematological, biochemical and production parameters.