Alleviation of heat stress by Chlorophytum borivilianum: impact on stress markers, antioxidant, and immune status in crossbred cows

Eighteen crossbred Karan Fries (KF) cows in mid-lactation (av. 130 days) were selected from the livestock herd of the institute. The treatment for the experimental cows was as follows: no supplement (control), a low dose of Chlorophytum borivilianum (CB) at a dose rate of 40 mg/kg BW/day (T1, n=6), and a high dose of CB at a dose rate of 80 mg/kg BW/day (T2, n=6) for a period of 90 days in hot-humid season. Physiological responses like respiration rate (RR), pulse rate (PR), and rectal temperature (RT) were recorded in the morning (8.00 A.M.) and afternoon (2.30 P.M.) at weekly intervals. The expression of pro-inflammatory (IL-1 beta and TNF-alpha) and anti-inflammatory cytokine (IL-10) in PBMCs, the plasma level of antioxidants (SOD, catalase, TBARS, and TAC), hormones (cortisol, prolactin), and energy metabolites (glucose, NEFA, urea, and creatinine) were determined. Dry and wet bulb temperatures and minimum and maximum temperatures were recorded, and the THI was calculated. The values of PR and RT were decreased (p<0.01) in the T2 group in comparison to T1. Plasma glucose level was lower, and NEFA, urea, and creatinine level were higher (p<0.01) in the control group as compared to T2 and T1 groups, respectively. Plasma cortisol and prolactin levels were significantly higher (p<0.01) in the control group and were lower in T1 and T2 groups. Feeding of CB in high dose decreased (p<0.01) plasma SOD, catalase, TBARS, and improved TAC levels in T2 over the T1 group. The dietary supplementation of CB at a dose rate of 80 mg/kg BW/day was more effective in lowering the stress level and augments the immunity by downregulating pro-inflammatory and anti-inflammatory cytokine levels. Therefore, dietary CB supplementation could be used as an effective heat stress ameliorator in dairy cows.