Influence of Asparagus racemosus on energy metabolism and lipid profile in crossbred dairy cows under summer thermal stress

Introduction

Heat stress is a pervasive and economically significant constraint to tropical dairy production. When ambient conditions exceed the thermoneutral zone, lactating cows experience reduced dry matter intake (DMI), impaired rumination, and decreased nutrient absorption, while simultaneously facing elevated maintenance energy requirements [1] . These interacting factors drive heat-stressed cows into a state of negative energy balance (NEB), diminishing the substrate available for milk synthesis [2,3] . The Temperature-Humidity Index (THI), is the standard indicator of heat stress intensity; values ≥72 are considered physiologically stressful for dairy cattle [4] . When summer thermal stress coincides with lactation periods, the metabolic disruption is compounded, making supportive nutritional interventions critical [5,6] . Synthetic feed additives, hormones, and pharmacological agents used to sustain productivity carry documented risks of residues in milk, adverse health effects, and high cost, motivating a global search for safe herbal alternatives [7] . Asparagus racemosus Willd. (Shatavari) is classified under the family Asparagaceae, distributed across tropical India, Asia, Australia, and Africa, and grows at low altitudes in shaded, humid conditions. The therapeutic use of A. racemosus is officially recorded in both the Indian Pharmacopoeia and the British Pharmacopoeia, lending it a well-established safety profile [8] . The herb's diverse bioactivities including galactagogue and mammogenic [9] , antioxidant [10] , antistress [11] , and digestive-enhancing properties [12] are largely attributed to its steroidal saponin constituents. In peri-parturient crossbred cows, shatavari root powder supplementation increased milk yield and improves milk quality traits, while reducing somatic cell count and subclinical mastitis, further supporting its functional role in dairy cows [13] . Ayurvedic tradition specifically recommends Asparagus roots as a cooling agent to counter summer heat [14] , a property mechanistically aligned with its antistress and adaptogenic functions [15] . The herb also increases DMI, feed digestibility, and feed conversion efficiency [16,14] , thereby sustaining energy availability under heat stress conditions. Despite these wellcharacterised properties, systematic investigation of A. racemosus supplementation specifically during summer thermal stress in crossbred dairy cattle with focus on energy metabolites and lipid fractions is lacking in published literature. The present study was therefore undertaken to evaluate the influence of A. racemosus root powder supplementation on plasma glucose, triglycerides, NEFA, total cholesterol, and HDL in lactating Jersey crossbred cows under summer thermal stress conditions.

Materials and Methods

The experiment was conducted at the Livestock Farm Complex, VCRI, Orathanadu, TANUVAS, situated in the Cauvery delta region of Tamil Nadu, India. The summer trial was conducted during April-May 2020. Ambient temperature ranged from a minimum of 24 °C to a maximum of 41 °C, with relative humidity (RH) of 60-78%. The Temperature-Humidity Index (THI) was calculated using the formula of Mader et al. (2006) [4]: THI = (0.8 × Ambient Temperature) + [ (% Relative Humidity ÷ 100) × (Ambient Temperature -14.4)] + 46.4. THI ranged between 82 and 86 throughout the study (Table 1), consistently exceeding the established critical heat stress threshold of 72 for dairy cattle [17] . The animals received a standard basal ration in accordance with ICAR (2010) nutrient requirement guidelines [18] . (2010) [19] . The control group received the basal ration without supplementation. The supplementation period was four consecutive weeks during the summer stress phase (Table 2). Fresh A. racemosus roots were collected from the Herbal Garden, Ethno Veterinary Herbal Product Research and Development Centre, TANUVAS, Orathanadu, Thanjavur District, Tamil Nadu. The roots were cleaned, shade-dried, and ground into a fine powder. Collection was standardized, maintained batch uniformity and minimise seasonal phytochemical variation. Blood samples were collected aseptically from the jugular vein at 06:00 am each week (Weeks 0 through 4). Approximately 6 mL of whole blood per animal was collected into EDTA-coated vacutainers (10% ethylene diamine tetra-acetic acid). Plasma was separated by centrifugation at 3, 500 rpm for 20 minutes used for instant sample analysis and remaining stored at -20 °C until further biochemical analysis. Glucose was estimated by GOD-POD endpoint assay using an Eppendorf Biospectrometer at 505 nm with Arkay diagnostic kit (Arkay, India) following the protocol of Kaplan (1984) [20] . Triglycerides were estimated by GPO-PAP endpoint assay using an Eppendorf Biospectrometer at 505 nm with Arkay diagnostic kit (Arkay, India) following the protocol of Nader et al. (1994) [21] . Non-Esterified Fatty Acids (NEFA) were estimated by colorimetric endpoint assay using a semi-automatic biochemistry analyser (Clindiag Systems, SA-20) at 505 nm with a Randox NEFA kit (Randox Laboratories Ltd., Antrim, UK) following the protocol of Matsubara et al.

(1983) [22] . Total cholesterol and HDL were each estimated by CHOD-PAP endpoint assay using an Eppendorf Biospectrometer at 505 nm with Arkay diagnostic kit (Arkay, India) following the protocol of Herbert (1984) [23] . All data were statistically analysed using methods described by Snedecor and Cochran (1994) [24] .

Results

Plasma Glucose

The mean plasma glucose concentrations (mg/dL) are presented in Table 3

Total Cholesterol

Mean plasma total cholesterol concentrations are presented in Table 4. The experimental group exhibited a consistent numerical elevation across all weeks (Week 4: 151.00±9.27 vs. 142.50±10.93 mg/dL); however, no statistically significant between-group or within-group differences were detected at any time point. Values in both groups remained within the normal reference range.

Plasma HDL

Mean plasma HDL concentrations are presented in Table 4. The control group showed progressive decline throughout the summer period, from 87.27±6.18 mg/dL at Week 1 to 78.91±4.20 mg/dL at Week 4. The experimental group showed a rising trend, reaching a peak of 108.42±8.54 mg/dL at Week 3 and 107.50±6.76 mg/dL at Week 4. Between-group differences were significant from Week 2 (p<0.05), Week 3 (p<0.05), and Week 4 (p<0.01).

Discussion

The weekly mean THI values of 84.08-84.63 recorded throughout the study were consistently above the critical threshold of 72 for dairy cattle in southern Indian summer conditions [17] , confirming sustained severe thermal stress. Under such conditions, reduced DMI and consequent negative energy balance are well-documented physiological responses in lactating dairy cows [1,2] .

Glucose

Plasma glucose values in both groups were within the normal reference range for lactating dairy cows, consistent with earlier reports [25,26,27] . The progressive decline in control group glucose concentrations reflects the negative effect of thermal stress on gluconeogenesis, reduced DMI. In contrast, the experimental group maintained significantly higher glucose levels at Weeks 2 and 4 (p<0.05). This glucogenic property is not attributable to the herb serving directly as an energy source [32] but to its saponins enhancing ruminal propionate production the principal gluconeogenic precursor in ruminants [31] as corroborated by Hu et al. (2006) [29] and Abreu et al. (2004) [30] . Additionally, A. racemosus increases DMI, feed digestibility, and feed conversion efficiency [16,17,14] , providing a greater flux of gluconeogenic substrate to the liver.

Triglycerides

Plasma triglyceride values were within the normal range in both groups, consistent with Piccione et al. (2012) [33] and Yehia et al. (2021) [34] . The experimental group maintained consistently lower triglyceride levels compared with controls from Week 2 onwards, though between-group differences did not reach statistical significance. The variation in both groups with the nadir at Week 2, aligns with the known effect of peak heat stress on hepatic lipid processing [35] . The numerical attenuation of triglycerides in the supplemented group is best explained by A. racemosusmediated mitigation of the heat stress response, reducing metabolic drive toward tissue lipid breakdown [28] .

NEFA

Circulating NEFA concentration is a sensitive indicator of adipose mobilisation and NEB severity; a relatively constant proportion of NEFA is utilised by the liver, making elevated NEFA a reliable biomarker of metabolic stress [36] . The progressive rise in NEFA in the control group (0.308 to 0.395 mmol/L) mirrors escalating energy deficit under sustained summer thermal stress and is consistent with findings of Barletta et al. (2017) [37] and Vaidya et al. (2017) [27] . High milk production demands combined with reduced feed intake represent the most critical phase for energetic drain, frequently culminating in ketogenesis [38] . The experimental group's significantly lower NEFA at Week 4 (p<0.05) and consistently suppressed values throughout the supplementation period demonstrate that A. racemosus effectively attenuated adipose lipolysis, mechanistically explained by saponin-enhanced propionate production [29,30] . Elevated NEFA during heat stress is strongly associated with postpartum metabolic disease and reproductive failure [38] , making this a practically important finding.

Total Cholesterol

The numerically higher but statistically non-significant total cholesterol concentrations in the experimental group across all weeks suggest improved hepatic function, consistent with the glucogenic and DMI-enhancing effects of A. racemosus. Values in both groups were within normal range, in agreement with Seifi et al. (2007), Piccione et al. (2012) [33] and Omur et al. (2016) [26] . Summer-induced reduction in DMI limits cholesterol synthesis substrate, and the resulting NEB may impose additional constraints on hepatic cholesterol synthesis in thermally stressed animals [39] . Saponins in A. racemosus may further modulate cholesterol metabolism by inhibiting pancreatic lipase activity and delaying intestinal fat absorption [40] .

HDL

The most statistically robust finding was the significant and progressive elevation of plasma HDL in the supplemented group, with significance at Weeks 2 and 3 (p<0.05) and at Week 4 (p<0.01)the strongest statistical outcome across all parameters. The control group exhibited a continuous HDL decline throughout the summer period (87.27 to 78.91 mg/dL), consistent with known adverse effects of thermal and metabolic stress on lipoprotein profiles [41,42] . The divergent HDL trajectory between groups was attributable to altered metabolic activity during summer stress [43] , modulated by A. racemosus in the experimental group. This HDL-elevating property is strongly corroborated by Visavadiya and Narasimhacharya (2005) [11] , who demonstrated an 11% increase in HDL-cholesterol with A. racemosus supplementation in hypercholesterolaemic rats, accompanied by significant reductions in LDL and VLDL. Elevated HDL facilitates reverse cholesterol transport, protecting hepatic integrity and reducing fatty liver risk in heat-stressed cows [44] .

Conclusion

Supplementation of Jersey crossbred dairy cows with Asparagus racemosus root powder at 200 mg/kg body weight/day for four weeks during summer thermal stress (THI 82-86) significantly elevated plasma glucose (Weeks 2 and 4; p<0.05), significantly attenuated NEFA concentrations (Week 4; p<0.05), and produced a progressive and statistically significant elevation in HDL (Weeks 2 and 3: p<0.05; Week 4: p<0.01), with consistent numerical improvements in triglycerides and total cholesterol.

Asparagus racemosus supplementation effectively ameliorated summer thermal stress-induced negative energy balance and dyslipidaemia through its saponin-mediated glucogenic, anti-lipolytic, and hypolipidaemic mechanisms, demonstrating its potential as a safe and effective herbal feed additive for tropical dairy management.

Acknowledgement

AcknowledgementsThe authors gratefully acknowledge the Livestock Farm Complex, VCRI, Orathanadu, TANUVAS, for providing experimental facilities and animal resources, and the Ethnoveterinary Herbal Product Research and Development Centre, TANUVAS, Orathanadu, for supplying the Asparagus racemosus plant material.

References

1. Beede DK, Collier RJ. Potential nutritional strategies for intensively managed cattle during thermal stress. J Anim Sci. 1986;62:543-554.
2. Moore CE, Kay JK, Collier RJ, VanBaale MJ, Baumgard LH. Effect of supplemental conjugated linoleic acids on heat-stressed Brown Swiss and Holstein cows. J Dairy Sci. 2005;88(5):1732-1740.
3. Shwartz G, Rhoads ML, Vanbaale MJ, Rhoads RP, Baumgard LH. Effects of a supplemental yeast culture on heat-stressed lactating Holstein cows. J Dairy Sci. 2009;92(3):935-942.
4. Mader TL, Davis MS, Brown-Brandl T. Environmental factors influencing heat stress in feedlot cattle. J Anim Sci. 2006;84(3):712-719.
5. Ingvartsen KL, Andersen JB. Integration of metabolism and intake regulation: a review focusing on periparturient animals. J Dairy Sci. 2000;83:1573-1597.
6. Ronchi B, Bernabucci U, Lacetera N, Nardone A. Oxidative and metabolic status of high yielding dairy cows in different nutritional conditions during the transition period. Proc 51st Annual Meeting EAAP, Vienna; 2000. p. 125.
7. Krishana L, Swarup D, Patra RC. An overview of prospects of ethano-veterinary medicine in India. Indian J Anim Sci. 2005;75(12):1481-1491.
8. Bopana N, Saxena S. Asparagus racemosus - ethnopharmacological evaluation and conservation needs. J Ethnopharmacol. 2007;110(1):1-15.
9. Pandey SK, Sahay A, Pandey RS, Tripathi YB. Effect of Asparagus racemosus rhizome (Shatavari) on mammary gland and genital organs of pregnant rat. Phytother Res. 2005;19(8):721-724.
10. Visavadiya NP, Narasimhacharya AVRL. Hypolipidemic and antioxidant activities of Asparagus racemosus in hypercholesteremic rats. Indian J Pharmacol. 2005;37(6):376-380.
11. Jayashree GV, Rachitha P, Krupashree K. Effect of roots of Asparagus racemosus (Shatavari) on stress in rats. Ethnopharmacology. 2000;71:425-435.
12. Dalvi SS, Nadkarni PM, Gupta KC. Effect of Asparagus racemosus shatavari on gastric emptying time in normal healthy volunteers. J Postgrad Med. 1990;36:91-94.
13. Kumar S, Saharan V, Sihag ZS, Sihag S. Dietary Supplementation of Shatavari (Asparagus racemosus) During Transition Period Influences Blood Metabolites, Milk Production and its Quality in Cattle . Indian J Anim Nutr. 2024; 41(1): 95-104.
14. Kumar V, Babu S, Revale AK, Meena RK, Kumar M, Ranjan, et al. Cultivation of medicinal plants in natural ecosystem in Gujarat (India). J Plant Dev Sci. 2014;6(3):425-435.
15. Saggu S, Kumar R, Singh VK, Govil JN. Stress management and herbal adaptogens. Chem Med Value. 2009;25:253-271.
16. Gupta N, Kumar A, Tiwari DP. Effect of herbs as feed additive on nutrient utilization and growth in crossbred heifers fed paddy straw based ration. Indian J Anim Sci. 2005;75(1):52-55.
17. Du Preez JH, Giesecke WH, Hattingh PJ, Eisenberg BE. Heat stress in dairy cattle under southern African conditions. Onderstepoort J. 1990;57:77-87.
18. ICAR. Nutrient requirements of cattle and buffalo. 3rd ed. Indian Council of Agricultural Research, New Delhi; 2010.
19. Kumar S, Mehla RK, Gupta AK, Meena RK. Influence of Asparagus racemosus (Shatavari) supplementation during different stage of lactation on oestrus behaviour and reproductive performance in Karan Fries crossbred cows. Livest Res Rural Dev. 2010;22(5):1-12.
20. Kaplan A. Carbohydrates and metabolites. In: Kaplan LA, Pesce AJ, editors. Clinical Chemistry: Theory, Analysis and Correlation. C.V. Mosby, Toronto; 1984. p. 1032-1040.
21. Nader R, Paul B, John A. Lipids, lipoproteins and apolipoproteins. In: Burtis CA, Ashwood ER, editors. Tietz Textbook of Clinical Chemistry. 3rd ed. W.B. Saunders, Philadelphia; 1994. p. 809-852.
22. Matsubara C, Neshikawa Y, Yoshida Y, Tatemura K. A spectrophotometric method for the determination of free fatty acid in serum using acyl-CoA synthetase and acylCoA oxidase. Anal Biochem. 1983;130:128-133.
23. Herbert K. Lipids. In: Kaplan LA, Pesce AJ, editors. Clinical Chemistry: Theory, Analysis and Correlation. C.V. Mosby, Toronto; 1984. p. 1182-1230.
24. Snedecor GW, Cochran WG. Statistical Methods. 8th ed. Affiliated East West Press Pvt. Ltd., New Delhi; 1994.
25. Singh SP, Mehla RK, Singh M. Plasma hormones, metabolites, milk production, and cholesterol levels in Murrah buffaloes fed with Asparagus racemosus in transition and postpartum period. Trop Anim Health Prod. 2012;44(8):1827-1832.
26. Omur A, Kirbas A, Aksu E, Kandemir F, Dorman E, Kaynar O, et al. Effects of antioxidant vitamins (A, D, E) and trace elements (Cu, Mn, Se, Zn) on metabolic and reproductive profiles in dairy cows during transition period. Pol J Vet Sci. 2016;19(4):697-706.
27. Vaidya MM, Singh SV, Upadhyay RC, Aggarwal A. Plasma profile of hormones and energy metabolites in low and high producing periparturient Sahiwal cows during summer and winter season. Indian J Anim Res. 2017;51(3):431-437.
28. Ahmad M, Bhatti JA, Abdullah M, Javed K, Ali M, Rashid G, et al. Effect of ambient management interventions on the production and physiological performance of lactating Sahiwal cattle during hot dry summer. Trop Anim Health Prod. 2018;50(6):12491254.
29. Hu WL, Liu JX, Guo YD, Wu YM. Effect of saponin on rumen fermentation and methanogenesis in vitro. Proc 12th AAAP Congress, Busan, South Korea; 2006. p. 221.
30. Abreu A, Carulla JE, Lascano CE, Diaz TE, Kreuzer M, Hess HD. Effects of Sapindus saponaria fruits on ruminal fermentation and duodenal nitrogen flow of sheep fed a tropical grass diet with and without legume. J Anim Sci. 2004;82:1392-1400.
31. Wiltrout DW, Satter LD. Contribution of propionate to glucose synthesis in the lactating and nonlactating cow. J Dairy Sci. 1972;55(3):307-317.
32. Kumar S, Mehla RK, Meena RK. Pre-and postpartum managemental intervention through herbal feed supplement (Asparagus racemosus) and its effect on production and reproduction performance in crossbred cows. Indian J Anim Sci. 2011;81(7):669-675.
33. Piccione G, Messina V, Marafioti S, Casella S, Giannetto C, Fazio F. Changes of some haematochemical parameters in dairy cows during late gestation, post partum, lactation and dry periods. Vet ir Zootech. 2012;58(80):59-64.
34. Yehia SG, Ramadan ES, Megahed EA, Salem NY. Influence of season and lactation stage on oxidative, haematological, and metabolic profile parameters in Holstein dairy cows. Adv Anim Vet Sci. 2021;9(12):2095-2102.
35. Teama FEI. Apolipoprotein B100 and some lipid components during transition period in cows under hot and thermoneutral environmental conditions. J Anim Plant Sci. 2016;26(2):366-372.
36. Pullen DL, Palmquist DL, Emery RS. Effect on days of lactation and methionine hydroxy analog on incorporation of plasma fatty acids into plasma triglycerides. J Dairy Sci. 1989;72(1):49-58.
37. Barletta RV, Maturana Filho M, Carvalho PD, Del Valle TA, Netto AS, Renno FP, et al. Association of changes among body condition score during the transition period with NEFA and BHBA concentrations, milk production, fertility, and health of Holstein cows. Theriogenology. 2017;104:30-36.
38. Fronk TJ, Schultz LH, Hardie AR. Effect of dry period overconditioning on subsequent metabolic disorders International Journal of Advanced Biochemistry Research https://www.biochemjournal.com and performance of dairy cows. J Dairy Sci. 1980;63(7):1080-1090.
39. Bobe G, Ametaj BN, Young JW, Beitz DC. Effects of exogenous glucagon on lipids in lipoproteins and liver of lactating dairy cows. J Dairy Sci. 2003;86:28952903.
40. Morehouse LA, Bangerter FW, DeNinno MP, Inskeep PB, McCarthy PA, Pettini JL, et al. Comparison of synthetic saponin cholesterol absorption inhibitors in rabbits: evidence for a non-stoichiometric, intestinal mechanism of action. J Lipid Res. 1999;40(3):464-474.
41. Kargar S, Ghorbani GR, Fievez V, Schingoethe DJ. Performance, bioenergetic status, and indicators of oxidative stress of environmentally heat-loaded Holstein cows in response to diets inducing milk fat depression. J Dairy Sci. 2015;98(7):4772-4784.
42. Tana S, Saraswati TR, Yuniwarti EY. Hematology and blood chemistry status of most frequently consumed ruminants in community. Biosaintifika. 2018;10(2):341-347.
43. Fujita M, Harada K, Yamashiro H, Kubota H, Yamamoto S. Difference in profiles of circulating lipoproteins and thyroid hormones in milking cows between the autumn and the summer. Nihon Chikusan Gakkaiho. 1996;67(6):519-525.
44. Martin D, Snider J, McGarry D, Hanson RW. Lipid metabolism I: synthesis, storage, and utilization of fatty acids and triacylglycerols. In: Devlin TM, editor. Textbook of Biochemistry with Clinical Correlations. 7th ed. John Wiley and Sons; 2010. p. 674-703.