Effect of dietary Phyllanthus emblica supplementation on biochemical stability of heat stressed Salem Black Goats

Introduction

Indigenous goat breeds are naturally adapted to harsh agro-climatic environments and are capable of surviving under poor feeding and stressful conditions more efficiently than exotic and crossbred animals (Akinyi, 2008) [1] . Their smaller body size and adaptive genetic potential enable them to maintain stable productivity even under limited nutritional and environmental resources (Nyamushamba et al., 2017) [7] . Among the different climatic stressors, heat stress is considered one of the major factors affecting livestock production, welfare and physiological stability, especially in tropical and subtropical regions (Banerjee et al., 2014) [3] . Prolonged exposure to elevated environmental temperatures adversely affects metabolic activities, growth and reproductive efficiency in goats. Salem Black goats, an important indigenous meat breed of Tamil Nadu, are well suited to hot and humid climatic conditions and are commonly reared in Salem, Dharmapuri, Krishnagiri, Erode and Namakkal districts (Aleena et al., 2018) [2] . However, continuous heat load can still induce physiological and biochemical disturbances. Nutritional supplementation using antioxidants has been suggested as a practical strategy to alleviate heat stress where conventional cooling systems are difficult to adopt (Kumar, 2009) [6] . Phyllanthus emblica (amla), a rich natural source of vitamin C, flavonoids and polyphenols, possesses strong antioxidant properties that help reduce oxidative stress and improve thermotolerance in goats (Randhawa et al., 2013) [9] .

Materials and Methods

The experiment was carried out at Livestock Farm Complex, Veterinary College and Research Institute, Namakkal, located between approximately 11°00′-12°55′ N latitude and 77°28′-78°50′ E longitude, at an elevation of approximately 192 m above mean sea level. The experiment was conducted during the summer season (March -May). The trial was carried out using eighteen adult, non-pregnant Salem Black does (3-5 years), randomly allotted into three groups (n = 6): T₁ (penhoused control), T₂ (sunlight exposure from 10:00 a.m. to 4:00 p.m. without supplementation) and T₃ (sunlight exposure with Phyllanthus emblica supplementation at 15 g/day/goat), following one week of acclimatization. The average meteorological data for the entire study period both inside the shed as well as outside are given in Table 1. Temperaturehumidity index (THI) was calculated using the formula (Marai et al., 2007): THI= [(0.8xT db ) +{(RH/100) x(T db -14.4)} +46.4]; where T db is dry bulb temperature (℃) and RH is relative humidity in per cent. Blood samples were collected aseptically from the external jugular vein of experimental goats at fortnightly intervals using heparinized tubes. Plasma was separated by centrifugation and stored at -20°C until further biochemical and endocrine analyses. Parameters including total protein, albumin, globulin were estimated periodically throughout the study.

Results

Plasma biochemical parameters were markedly influenced by heat stress during the experimental period. Plasma total protein, albumin and globulin concentrations showed a progressive decline in heat-stressed goats without supplementation (T₂), with significantly lower (P < 0.05) values observed on the 30 th and 45 th day compared to control (T₁) and supplemented goats (T₃). The reduction was more pronounced on the 45 th day, where T₂ recorded the lowest total protein (4.61 ± 0.11 g/dL), albumin (3.91 ± 2.68 g/dL) and globulin (1.91 ± 2.45 g/dL) levels. In contrast, Phyllanthus emblica supplemented goats (T₃) maintained biochemical values closer to control animals, indicating the ameliorative effect of supplementation against heat stressinduced alterations in protein metabolism.

Discussion

Total protein, albumin and globulin are considered important indicators of nutritional and physiological status in livestock exposed to environmental stress conditions (Attia et al 2016). In the present study, plasma total protein, albumin and globulin concentrations showed a progressive decline in heatstressed goats without supplementation (T₂), particularly on the 30 th and 45 th day of the experiment. The reduction in these parameters may be attributed to decreased feed intake, altered protein metabolism and enhanced protein catabolism during heat stress conditions. Similar reductions in plasma protein fractions under heat stress were previously reported in goats and sheep by Singh et al (2016) [11] and Pandey et al (2012) [8] , who attributed these changes to impaired hepatic synthetic activity and increased maintenance energy requirements during thermal stress. In contrast, goats supplemented with Phyllanthus emblica (T₃) maintained plasma total protein, albumin and globulin values closer to control animals throughout the study period, indicating the protective effect of supplementation against heat stress-induced metabolic alterations. Similar ameliorative effects of herbal antioxidant supplementation on plasma protein profile under heat stress conditions were also reported by Banerjee et al (2015) [4] and Sejian et al (2013) [10] . However, Helal et al (2010) [5] observed increased plasma protein and albumin concentrations during short-term heat exposure in goats, which could be due to differences in duration and intensity of heat stress as well as breed adaptability.

Conclusion

The study revealed that heat stress significantly affected the biochemical profile of Salem Black goats by reducing plasma total protein, albumin and globulin concentrations in nonsupplemented animals. These changes indicate impaired metabolic and physiological stability under thermal stress conditions. Supplementation with Phyllanthus emblica powder effectively alleviated the adverse effects of heat stress and maintained biochemical parameters closer to normal values. The findings suggest that Phyllanthus emblica supplementation improves thermotolerance and adaptive capacity in Salem Black goats under tropical heat stress conditions. Therefore, it can be recommended as a beneficial nutritional strategy for maintaining goat health and productivity during summer stress.

References

1. Akinyi OI. Economic analysis of indigenous small ruminant breeds in the pastoral system: A case of sheep and goats in Marsabit District, Kenya. 2008.
2. Aleena J, Sejian V, Bagath M, Krishnan G, Beena V, Bhatta R. Resilience of three indigenous goat breeds to heat stress based on phenotypic traits and PBMC HSP70 expression. International Journal of Biometeorology. 2018. doi:10.1007/s00484-018-1604-5.
3. Banerjee D, Upadhyay RC, Chaudhary UB, Kumar R, Singh S, Ashutosh GM, et al. Seasonal variation in expression pattern of genes under HSP70 family in heat and cold adapted goats. Cell Stress and Chaperones. 2014;19:401-408.
4. Banerjee D, Upadhyay RC, Chaudhary UB, Kumar R, Singh S, Ashutosh, Das TK, De S. Seasonal variations in physio-biochemical profiles of Indian goats in the paradigm of hot and cold climate. Biological Rhythm Research. 2015;46:221-236.
5. Helal A, Hashem ALS, Abdel-Fattah MS, El-Shaer H. Effects of heat stress on coat characteristics and physiological responses of Balady and Damascus goats in Sinai, Egypt. American-Eurasian Journal of Agriculture and Environmental Science. 2010;7:60-69.
6. Kumar M. Reproductive performance and blood biochemical profile of summer stressed goats following antioxidant supplementation. Ludhiana, India: Guru Angad Dev Veterinary and Animal Sciences University; 2009.
7. Nyamushamba GB, Mapiye C, Tada O, Halimani TE, Muchenje V. Conservation of indigenous cattle genetic resources in Southern Africa's smallholder areas: Turning threats into opportunities-A review. AsianAustralasian Journal of Animal Sciences. 2017;30:603621.
8. Pandey N, Kataria N, Kataria AK, Joshi A. Ambient stress associated variations in metabolic responses of Marwari goats of arid tracts in India. Journal of Stress Physiology and Biochemistry. 2012;8:120-127.
9. Randhawa HK. Effect of amla powder supplementation on physiological and blood biochemical responses in heat stressed goats. Ludhiana, India: Guru Angad Dev Veterinary and Animal Sciences University; 2013.
10. Sejian V, Indu S, Naqvi SMK. Impact of short-term exposure to different environmental temperatures on the blood biochemical and endocrine responses of Malpura ewes under semi-arid tropical environment. Indian Journal of Animal Sciences. 2013;83:1155-1160.
11. Singh KM, Singh S, Ganguly I, Ganguly A, Nachiappan RK, Chopra A, et al. Evaluation of Indian sheep breeds of arid zone under heat stress condition. Small Ruminant Research. 2016;141:113-117.