Oxidative stress parameters
Superoxide dismutase
The mean concentration of plasma superoxide dismutase showed non-significant difference between all the groups (Table 2). The pattern of results indicates that, the maximum concentration of plasma superoxide dismutase was observed in combination of organic mineral supplemented group (T13) whereas, in groups supplemented with separately Zn, Se or Cr, the maximum concentration of plasma superoxide dismutase was observed in organic Zn supplemented group (T4) followed by T3 than T2 group.
In present investigation the level of superoxide dismutase (SOD) was increased by Zn supplementation. The probable reason for the increase might be the fact that zinc act as a structural component of SOD. Superoxide dismutase is localized in cytoplasm, which includes Cu and Zn at its catalytic site. The enzyme SOD acts as the first line of antioxidant defence by catalyzing the conversion of the superoxide anion into hydrogen peroxide and oxygen.
Present findings are in accordance with earlier work of
Rama Rao et al., (2016). They reported that improvement in activity of SOD with supplementation of Se, Zn or Cr as compared to those fed the control diet without OTM. In another study Suri, (2015) reported that the activity of superoxide dismutase differed significantly with variation in source of Zn supplementation and the activity of SOD (p<0.05) was highest at 70 ppm (5.27 units/mg protein.).
Glutathione peroxidase
The mean concentration of plasma glutathione peroxidase showed non-significant difference between all the groups (Table 3). The pattern of results indicates that the maximum concentration of plasma glutathione peroxidase was observed in organic mineral supplemented group (T13) whereas, in groups supplemented separately with Zn, Se or Cr, the maximum concentration of plasma glutathione peroxidase was observed in organic Se supplemented group (T7) followed by T6 than T5 group. The probable reason for this might be the activation of glutathione peroxidase requires small amounts of Se (selenocysteine), probably substituting sulphur in the glutathione molecule and causing development of modified enzyme GPx4. Lipid peroxidation in plasma was decreased, while activities of GPx and glutathione reductase in plasma increased linearly with Se concentration in a broiler chicken diet as reported by
Rama Rao et al., (2013).
Catalase
On day 35 the mean concentration of plasma catalase showed significant (p<0.01) difference between all the groups (Table 4). Significantly (p<0.01) higher level of plasma catalase was found in T4 (16.265 ± 0.80 ng/ ml), T12 (17.287 ± 2.76 ng/ ml) and T13 (20.230 ± 1.66 ng/ ml) groups.
Present findings are in accordance with Rama Rao
et al., (2013) who found that red blood cell catalase (RBCC) increased linearly (p<0.01) with increase in Se concentration in diet. Catalase is a heme-containing antioxidant enzyme that acts sequentially with SOD in the conversion of hydrogen peroxide to water thereby protecting the cells against hydrogen peroxide toxicity and LPO (
Suri, 2015).
Thio-barbituric acid value
The mean plasma thio-barbituric acid value showed significant difference (p<0.01) between all the groups (Table 5). The maximum plasma thio-barbituric acid value was observed in T1 group whereas, minimum plasma thio-barbituric acid value was observed in T13 group during experimental period. The decrease in plasma MDA concentration could be due to the increased activity of SOD, Gpx and CAT and decrease in the damage of tissues by OTM (
Rama Rao et al., 2016).
Present findings were much similar to findings of
Sahin et al., (2005). They observed linear decrease (P<0.05) in malondialdehyde (MDA) concentration in heat stressed Japanese quails by addition of 30 or 60 mg Zn/kg basal diet either from organic (zinc picolinate) or inorganic source (Z
nSO
4), with relatively higher improvement in birds supplemented with organic zinc source compared to inorganic source.
Attia et al., (2015) reported that dietary supplementation of chromium, selenium and vitamin C separately or in combination decreased MAD concentration (p<0.05) in heat
-tressed birds as compared with the control group. Rama
Rao et al., (2016) found that the lipid peroxidation was reduced (p<0.05) with supplementation of Se or Cr compared to the broilers fed the control diet, while the lipid peroxidation in Zn supplemented groups was intermediate. Contrary to these findings,
Echeverry et al., (2016) studied that organic trace mineral supplementation showed no difference in plasma MDA level between control and OTM treatment (p
>0.05) groups.
Biochemical parameters
Plasma glucose concentration
The statistical analysis showed non-significant (p>0.05) difference in plasma glucose concentration among the different treatment groups but the pattern of results indicates minimum concentration of plasma glucose in organic chromium supplemented group of broilers (Table 6). The lower circulatory glucose concentration in the Cr supplemented birds was perhaps indicative of an increased turnover rate and utilization of glucose at the tissue level.
Tawfeek et al., (2014) reported that serum glucose level was significantly lowered in Cr; vitamins and Zn + Se groups which ranged from 80 to 87% as compared to control group (280 mg/dl).
Rosebrough and Steele (1981) reported Cr as a cofactor for insulin activity and that it is necessary for normal glucose utilization and healthy animal growth. Insulin regulates metabolism of carbohydrate, fat and protein, stimulating amino acid uptake and protein synthesis as well as glucose utilization in tissues.
Total protein, Albumin and Globulin concentration
The mean total plasma protein, albumin and globulin concentration showed significant difference (p<0.01) between all the groups (Table 7, 8 and 9 respectively). Total plasma protein, albumin and globulin were higher for organic chromium supplemented groups.
The present findings were in agreement with
Tawfeek et al., (2014) who reported that supplementation of Zn + Se and Cr significantly increased total protein levels in plasma.
Attia et al., (2015) also reported that separately or in combination, supplemental Cr, Se or Vitamin C increased serum concentrations of total protein, albumin and globulin which are in agreement with present findings.
The probable reason behind increased serum concentration of total protein may be due to the involvement of Cr in protein metabolism. Chromium is thought to have a role in nucleic acid metabolism because it increased in the stimulation of amino acid incorporation into liver protein. It is expected that Cr might have effects on circulating proteins because of its role in protein synthesis. The increase in serum albumin may be due to increased amino acid synthesis in the liver, suggesting that Cr may improve amino acid synthesis.
Contrary to these findings
Echeverry et al., (2016) reported that the overall analysis of total protein, fibrinogen, total protein/fibrinogen ratio, albumin, globulin did not show any difference among OTM treatments (p
>0.05) and control group.
Production performance parameters of broilers
Body weight
Significant difference (p<0.01) was observed in body weight gain between all the groups (Table 10). The maximum body weight gain (2141.25 ± 49.53 g) was attained in T13 group, supplemented with combination of organic form of Zn, Se and Cr followed by T7 group which were supplemented with organic form of selenium whereas, minimum body weight gain (1403.29 ± 21.24 g) was attained in T1 (control group). It may be due to the use of organic minerals which can improve intestinal absorption of trace elements as they reduce interference from agents that form insoluble complexes with the ionic trace elements and thereby enhancing their bioavailability and body weight gain.
Present findings were in agreement with the results of Rama
Rao et al., (2016), they reported that supplementation of Se, Cr and Zn as organic form significantly increased (p<0.05) body mass gain as compared to those fed the control diet. Among the trace minerals supplemented groups, the growth was significantly (p<0.05) higher in broilers fed with Se as compared to those fed Zn or Cr.
Echeverry et al., (2016) also reported that body weight was not different in OTM treatments compared to control (p
>0.05).
Feed intake
Significant difference (p<0.01) in total feed intake (Kg) was observed between all the groups during entire experimental duration (Table 11). Maximum feed intake was observed for T13 (2.40 ± 0.09 kg) group and minimum feed intake was observed for T5 (1.87 ± 0.09 g) group. This might be due to synergistic effect of stress alleviating nutritional agents (OTM), they in turn may had helped in improvement of feed intake in broilers.
The present findings of significant influence of feed consumption was in agreement with the results of
Rahaman et al., (2008), they reported that Ross broilers fed with zinc- methionine (40, 80 and 120 mg/kg) showed significantly higher feed intake as compared to inorganic source fed groups.
Hamidi et al., (2016) found that improved cumulative weight gain was observed with diet supplemented with Chromium Picolinate in birds.
Feed efficiency ratio
FER differ also significantly (p<0.01) for all the treatment groups as compare to control group (Table 12). Maximum FER was observed for T7 (0.90 ± 0.02 g) followed by T13 (0.89 ± 0.01 g) and T12 (0.88 ± 0.01 g) group whereas, minimum FER was observed for T1 (0.65 ± 0.01 g) group.
Performance index
Significantly (p<0.01) maximum performance index was observed in T7 (1843.20 ± 64.28) and T13 (1944.44 ± 89.56) group whereas, minimum PI was observed for T1 (921.17 ± 28.09 g) and T2 (1030.47 ± 32.85 g) group (Table 12).
FER and PI were also significantly (p<0.01) different for the all treatment groups as compared to control group. Maximum FER and PI were observed in T7 followed by T13 and T12 group whereas, minimum FER and PI was observed for T1 group. This might be due to improvement in body weight gain and feed intake in broilers.
The present observations are in agreement with the findings of
Krstic et al., (2012), they reported that increased feed efficiency and body weight gain in broilers diet supplemented with Se-enriched yeast.
Mortality
On perusal of data, it was observed that, mortality in broilers was found in only T8 (4.17%) and T9 (4.17%) group (Table 12).
Tawfeek et al., (2014) reported that supplementation of antioxidants improved the viability and decreased the mortality to the degree that no deaths occurred in the Zn + Se and Cr supplemented group.
Echeverry et al., (2016) also reported that mortality in the OTM treatment group was 20% lower as compared to control.
