AMELIORATION OF HEAT STRESS INDUCED OXIDATIVE DISTURBANCES BY HERBAL ANTIOXIDANTS IN BROILER CHICKEN
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Date
2011-04
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SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA
Abstract
ABSTRACT:
A study was petformed to evaluate the antioxidative potential of herbals Tulsi
(Ocimum sanctum) and Turmeric (Curcuma longa) in combating heat stress with
two batches of broiler chicks in hot summer months. Each batch consisted of a
total of 108 one day OM Vencobb broiler chicks which were grouped and offered 9
types of dietary regimens wtth variable concentrations and combinations of
antioxidants. A group of 12 chicks was raised separately in stress free
environment on basal diet without any antioxidant supplementation as control.
Body weights and feed intake were measured at weekly intentab. The blood
samples were colleded at 4" and 6" wk of age and haernatological estimations
(RBC, WBC, Hb. & PCV) were carried out within 2 hrs of collection. While serum
samples were preserved at -20°C until utilized for estimation of protein profiles
(TP, albumen, globulin concentrations and A:G ratios), serum cortisol
concentrations, humoral and cell mediated immune responses. Plasma samples
were prepared by centrifugation, stored and utilized for analysis of enzymatic and
non enzymatic antioxidant concentration. At the end of trail, breast and meat
samples were procured by excision of sacrificed birds for studying organoleptic
properties and lipid peroxidation. Histopathological studies of liver, bursa, brain
and spleen were conducted to observe the tissue changes at the end of the
experiment. The performance parameters (Body weights and feed efficiency),
haernatologoical parameters (RBC, Hb. PCV and WBC), enzymatic (GSH-PX,
Catalase and SOD), non enzymatic (Reducedglutathione) antioxidant
concentrations, immunological indices (HI titers and CMI responses) were
signifiintly low (PsO.01) in heat stressed birds compared to control and
antioxidant supplemented groups. However, WBC count, serum cortisol
concentrations, serum ALP and ALT activities were significantly (PS0.01) higher in
heat stressed birds compared to control group. Histopathological study evidenced
degenerative changes and pathological lesions in tissues collected from heat
8tmssed birds, While no lesions of pathological importance were observed with the
tissues d control group. Sensory chamderistics of breast meat samples from heat
stressed birds scored low on 5 point hedonic scale (3.42 for colour, 3.12 for
texture, 3.42 for juiciness, 3.22 for tlavour and 3.14 for overall acceptability)
compared to higher scores recorded for meat samples of control group.
Dietary supplementation with herbals Tulsi and Turmeric was proved beneficial
in terms of broiler performance, haematological, serological values. immunological
indims and antioxidant status. Their inclusion also contributed to low levels of
serum cortisol and improved sensory characteristics and reduced lipoperoxidative
damage of broiler meat. Of the two herbals employed for the study. Turmeric had contributed to
hgher body weights (1629.17 g and 1627.50 g with 0.2% and 0.4% level of
inclusions, respectively), which were comparable with the weights achieved by
supplementing the diet either with vitamin E alone (1637.52 g) and its combination
with Selenium (1656.67 g) end control group (1684.17 g) at the end of 6'" week,
Feed efficiency though low in the initial stages, an accelerated trend was noticed
from 4m wk onwards wrth Turmeric supplementation. And even sensory
attributes showed higher sensory scores with Turmeric supplementation at either
of the dose. While, Tulsi, contributed to significantly (Ps0.01) higher concentration
of enzymatic and non enzymatic antioxidants, blood and serum variables, and
immunological indices at either of the dose supplemented. Herbals at higher
concentration (Ocimum at 0.5% and Turmeric at 0.4%) had shown improved
antioxidant -8. However, the two herbals when given in combination at
different doses could not yield any additive effect.
The benefdal results obtained with the supplementation of herbals at different
doses were however remained low when compared to the values obtained with
the diets inclusive of vitamin E alone, or its combination with Se and control
group. But, considering the cost of these synthetic antioxidants vitamin E and Se
and maintaining the birds in stress free environment, the herbals employed Tulsi
and Turmeric in this study may be suggested as natural and economical
alternatives in amelioration of heat stress and achieving higher performance
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