Archives

The following table 1 shows the ambient temperature of autumn & winter as recorded at 15th day interval at different period for the shades of experimental animals.

Table1: Ambient temperature (ºC) of autumn and winter season at different periods (Mean±SE)

NS - P≥0.05; *P<0.05 - Significant; **P<0.01- Highly Significant

As observed from table no-I, mean ambient temperature in autumn recorded 15th day interval was 17.27±0.40, 15.29±0.53, 16.43±1.07 and 10.74±1.03 at 15th, 30th, 45th and 60th day respectively (Table 1, Fig 1). The mean ambient temperature was found to be significantly lower (p<0.01) on day 60th during autumn. Similarly, during winter season, the mean ambient temperature recorded on 15th day was found to be significantly (p<0.01) higher as compared to that was on day 30th and 45th. The mean ambient temperature was found to be 6.91±0.62, 3.55±0.60, 3.89±0.40 and 5.16±0.88 on 15th day, 30th, 45th and 60th respectively. Significantly lower level of ambient temperature (p<0.01) was observed on day 60 as compared to day 15, 30 and 45 during autumn. The difference in ambient temperature between autumn and winter was found to be highly significant on each fortnight, it was higher during autumn whereas it was lower than the thermal comfort zone (12-24) during winter, and it was ≤ 5 which creates cold stress in animals.
2.6.2 Relative humidity (%)

Table-2 suggests that the difference between Relative humidity was non-significant between Autumn and Winter at all the fortnights except for that at day 15th the t-value (p critical) in that case was 0.04 (p<0.05) and thus the relative humidity was significantly higher in Autumn (69±0.33) than in winter (66.4±1.22). Relative humidity on 15th, 30th, 45th and 60th day in Autumn was observed to be 69±0.33, 70.06±1.29, 66.4±2.43, and 65.26±1.76 respectively (Table 2, Fig 2), while during winter, the relative humidity was found to be 66.4±1.22, 66.73±1.65, 67.8±0.50 and 67.53±0.74 on 15th, 30th, 45th and 60th day respectively.

Table 2: Relative humidity (%) of autumn and winter season at different periods (Mean±SE)

NS - P≥0.05; *P<0.05 - Significant; **P<0.01- Highly Significant

Statistically, non-significant differences were observed in average relative humidity (%) on different fortnights during autumn as well as during winter. There was a gradual fall in relative humidity during winter whereas a rise was observed on day 30 during autumn followed by a gradual fall on day 45 and 60. In our finding the average relative humidity during winter was higher than the findings of Rathwa et al. (2017), because of heavy rainfall in this region (tropical humid).
2.6.3 Temperature humidity index

The mean (Temperature humidity index) THI value have been found to be 72.48±0.45, 70.45±0.60, 72.73±1.23 and 66.64±0.97 for 15th, 30th, 45th and 60th day respectively. The F value of 10.54 (P<0.01) was highly significant indicating significant variation in THI value at periodical interval. The highest mean THI value was 63.87±0.56 as recorded at 15th day of winter followed by mean value of 57.58±0.91, 58.29±0.68 and 60.89±1.13 at 30th, 45th and 60th day respectively. The difference between THI value of autumn and winter was found to be highly significant (P<0.01) at 15th, 30th, 45th day interval and significant (P<0.05) at 60th day interval. Although the (Table 3, Fig 3) THI value of autumn was higher than winter at all the four fortnightly intervals.

Table 3: Temperature humidity index of autumn and winter season at different periods (Mean±SE)

NS - P≥0.05; *P<0.05 - Significant; **P<0.01- Highly Significant

In the present study, significant differences were observed within season as well as between seasons. Significantly lower level of THI (p<0.01) was observed on day 60 during autumn whereas significantly lower level of THI (p<0.01) was observed on day 30 and 45 as compared to day 60 and 45. The THI was significantly higher during autumn as compared to winter is in consistent with the findings of Rathwa et al. (2017) who also reported a higher THI during summer.
2.7 Oxidative Stress Parameter:
2.7.1 Lipid peroxidation (LPO)
Lipid peroxidation in tissue homogenate was estimated in terms of malondialdehyde (MDA) production by the modified method of Stock and Dormandy (1971) as described by Jain (1988).
0.5 ml of tissue homogenate was suspended in 0.5 ml of PBS. To this 0.5 ml of 30 % TCA was added. Tubes were vortexes and allowed to stand on ice for at least 2 h. Tubes were centrifuged at 2000 rpm for 15 minutes. 1 ml of the supernatant was transferred into another tube and to this 0.075 ml of 0.1 M EDTA and 0.25 ml of 0.67 % thiobarbituric acid in 0.05 M NaOH was added. It was mixed and the tubes were kept in a boiling water bath for 15 min and then allowed to cool at room temperature. Absorbance was read at 532 nm. The amount of lipid peroxidation is expressed in nanomoles of MDA formed per mg of protein.

nM/mg protein =	OD	x	Total vol. in cuvette	x	Path length (cm)
	€		Vol. of sample		mg/protein/ml sample

 

2.7.2 Superoxide Dismutase Activity (SOD)

Superoxide dismutase (SOD) was estimated as per the method described by Mahesh and Balasubramanian (1998). It involves generation of superoxide by pyrogallol autoxidation and the inhibition of superoxide dependent reduction of the tetrazolium dye MTT [3-(4-5 dimethyl thiazole 2-xl) 2.5 diphenyltetrazolium bromide] to its formazan, measured at 570 nm. The reaction was terminated by the addition of dimethyl sulfoxide (DMSO), which helps to solubilize the formazan formed. Briefly, the reaction mixture contained (0.65 ml PBS), pH 7.4, 30 µl 3-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT; 1.25 Nm), 75 µl pyrogallol (100 Mm), and 10 µl hemolysate or tissue homogenate. The mixture was incubated at room temperature for 5 min and the reaction was stopped by adding 0.75 ml of dimethyl sulfoxide. The absorbance was read at 570 nm in a spectrophotometer. The enzyme activity has been expressed as uM MTT formazan formed/min/mg protein, using a molar extinction coefficient of 17000 M-1 cm-1 The colour evolved is stable for many hours, and expressed as uM of MTT formazan formed/mg protein.

µM MTT formazen =	ODt-ODc	x	Total vol. in cuvette	x	Path length (cm)
	€		Vol. of sample		mg/protein/ml sample

 

2.7.3 Reduced Glutathione (GSH)
GSH was estimated by the method of Prins and Loos (1969). Briefly, 0.2 ml of whole blood or tissue homogenate was mixed with 4 ml of 0.08 N H2SO4. After 10 min, 0.5 ml of tungstate solution (0.3 M Sodium tungstate and 0.1 M EDTA) was added and mixed vigorously for 5 min to clear the brown hemolysate. After allowing it to stand for 5 min to avoid crust formation on top of the supernatant, it was centrifuged for 20 min at 2000 rpm at room temperature. Two ml of supernatant was mixed with 2.5 ml of Tris buffer (1M; pH 8.0 and 0.2 ml of 5, 5-dithiobis-2-nitrobenzoic acid reagent. The absorbance was read immediately at 412 nm in spectrophotometer. The GSH content has been expressed as mM/ml blood or mM/g tissue by using a molar extinction coefficient of 13.6  103 M-1 cm-1.

RESULT AND DISCUSSION

Climatic changes have range of impact on physical, mental & community health of animals. The present experiment was conducted to study the effect of meteorological variables on oxidative stress in Black Bengal Goat. Harsh environments constitute stressful conditions to animals raised in extreme climatic areas, and as a result, animals develop various adaptive mechanisms that enable them to survive under conditions of extreme heat or extreme cold.
3.1 Lipid Peroxidation (mol of MDA produced /ml)
The process of lipid peroxidation is one of oxidative conversion of polyunsaturated fatty acids known as melanodialdehyde (MDA), which is the most commonly studied, biologically relevant free radical reaction (Esterbauer et al., 1991 & Celi, 2011) and considered to be the best indicators of oxidative stress (Nielsen et al., 1997 & Georgieva, 2005).

Lipid peroxidation level (mol of MDA) in Black Bengal goats was compared during autumn and winter. Using independent t- test, the periodical variation in the lipid peroxidation level at fortnightly interval was analyzed with one way ANOVA. The effect of 15-day interval was highly significant during both autumn as well as during winter (P<0.01). In the present study, the mean value of lipid peroxidation level (nmol of MDA/ml of packed cells) of Black Bengal Goat was 0.51±0.01, 0.54±0.008, 0.55±0.006, 0.56±0.005 in Autumn and 0.59±0.009, 0.62±0.012, 0.65±0.012, 0.67±0.011 in Winter (Table 4, Fig 4) on day 15th, 30th, 45th& 60th. The independent t test (t value P critical) shows that the effect of season on the above-mentioned parameter was highly significant (P<0.01) at all the periodical intervals. While the mean value of lipid peroxidation (mol of MDA) in winter was greater than autumn at all the periodical interval mentioned.

Table 4: Lipid peroxidation (nmol of MDA/ml) of Black Bengal Goats in autumn and winter season at different periods (Mean±SE)

NS - P≥0.05; *P<0.05 - Significant; **P<0.01- Highly Significant

Increasing trend was observed in the level of LPO during winter. Significantly higher levels of LPO were observed on each fortnight during winter as compared to autumn. Which indicates stress level was increased during this period. However, the level was lower in comparision to the findings of Rathwa et al. (2017).
3.2 Superoxide dismutase (IU/ml)
Super dismutase (SOD) is the important antioxidant enzyme present in the body and provides defensive mechanism against free radical mediated oxidative damage. Antioxidant activity of SOD mediated by dismutation reaction, where SOD scavenges highly reactive superoxide radical and converts it to oxygen molecule and less reactive H2O2 molecule (Fridovich, 1972). Superoxide dismutase (U) of Black Bengal Goats in Autumn and Winter season was found out at different periods (Mean±S.E) namely 15th, 30th, 45th and 60th day i.e at an interval of 15 days between the two periods. The effect was found to be highly significant between autumn and winter season (P<0.01) at all the periodical intervals on the basis of t -values. The mean values were greater during autumn than winter in all the cases. The one-way ANOVA predicted non- significant effect during autumn and highly significant effect during winter for the variation due to 15-day interval.
The mean value of SOD in the present study was 616.42±15.30, 563.23±14.32, 505.59±14.06 and 485.76±18.39 during autumn while the mean value of SOD during winter was 696.32±19.59, 689.39±19.49, 676.96±20.72 and 651.08±17.10 respectively (Table 5, Fig 5) on day 15th, 30th, 45th and 60th.

Decreasing trend was observed in the level of SOD, which was significantly higher on day 15 and 30 as compared to day 60 during autumn. Our findings were in agreement with the findings of Rathwa et al.(2017) in sheep. The higher SOD activity in black Bengal goats during winter season was probably a response to higher superoxide generated in these animals. Superoxide dismutase catalyzes the dismutation of superoxide to oxygen and hydrogen peroxide. Thus, a higher SOD activity leads to increase in hydrogen peroxide level in the cells which is metabolized by intra cellular components by GPx which protecting the organism against deleterious effects of free radicals.

Table 5: Superoxide dismutase (IU) of Black Bengal goats in autumn and winter season at different periods (Mean±SE)