# Effects of Herbal Supplementation on Growth Performance of Kenguri Sheep Exposed to Heat Stress

## TL;DR

This study shows that herbal supplements can help heat-stressed Kenguri sheep by improving hormone levels and gene activity related to growth, even if they don't increase body weight.

## Contribution

The study introduces herbal supplementation as a novel strategy to mitigate heat stress effects on growth-related endocrinology and gene expression in Kenguri sheep.

## Key findings

- Herbal supplements increased feed intake and growth-related hormones in heat-stressed ewes.
- Herbal supplements reversed heat stress-induced downregulation of growth-related genes like GHR, IGF1, and PRLR.
- Despite no change in body weight, herbal supplements improved endocrine and gene expression profiles.

## Abstract

Sheep husbandry has played a crucial role in supporting rural livelihoods. However, climate change associated heat stress in sheep has a detrimental impact on growth performance. In order to address the negative effects of heat stress on animal growth, scientists have been exploring nutritional solutions like herbal supplements as they have significant effects on feed intake, water intake, and hormonal and molecular mechanisms governing growth in major livestock. However, negligible studies have delved into these aspects in heat-stressed sheep. Thus, the study targeted addressing these concerns focusing on the native Indian sheep breed, Kenguri. The 60-day study conducted using 24 ewes was divided into four groups under different treatments in climate-controlled chambers, including herbal supplementation. The results indicated that herbal supplements improved feed intake and growth-related hormones in heat-stressed ewes. Further, the herbal supplement had a significant role in increasing the expression pattern of genes governing growth. The study established that herbal supplements support the growth performance of heat-stressed sheep. The conclusions show promise for improving climate resilience in Kenguri ewes and open the way for navigating future strategies that sustain sheep production through innovative nutrition and breeding strategies.

A study was designed to explore the possibility of using herbal supplementation to sustain growth performance during heat stress exposure in Kenguri sheep. This 60-day study was conducted on 24 Kenguri ewes (1–2 years old), randomly assigned to four treatment groups (n = 6 per group) as follows: KC (n = 6; Kenguri Control), KHS (n = 6; Kenguri Heat Stress), KCS (n = 6; Kenguri Control and herbal supplement), and KHSS (n = 6; Kenguri Heat Stress and herbal supplement). The herbal mixture of Ocimum sanctum (Tulsi), Emblica officinalis (Amla), Morinda citrifolia (Noni), Withania somnifera (Ashwagandha), and Phyllostachys edulis (Bamboo) was used in this study. The herbal supplement used in the present study was given to the KCS and KHSS groups’ animals in dry powder form at a dose of 0.8 g/Kg BW/Day. All variables were recorded fortnightly, and gene expression analysis was performed at the end of the experiment. The results indicated that the recorded temperature–humidity index (THI) provided thermal comfort for KC and KCS while inducing extremely severe heat stress to the KHS and KHSS groups. Heat stress did not alter the feed intake, while the herbal supplement during heat stress increased the feed intake from day 30 onwards. Furthermore, heat stress significantly (p < 0.001) increased the water intake, while the herbal supplement did not alter the heat stress-induced water intake. In addition, neither heat stress nor herbal supplements influenced the body weight and allometric measurements studied. Furthermore, heat stress significantly (p < 0.01) decreased the level of plasma tri-iodo-thyronine (T3) and thyroxin (T4) and had a non-significant effect on plasma growth hormone (GH), insulin-like growth factor-1 (IGF-1), while the herbal supplements significantly (p < 0.01) increased the levels of all these hormones studied. Likewise, in peripheral blood mononuclear cells (PBMCs) the expression patterns of growth hormone receptor (GHR), Insulin-like growth factor 1 (IGF1) and prolactin receptor (PRLR) were significantly (p < 0.001) downregulated during heat stress (0.25, 0.3, and 0.48-fold change, respectively). However, the herbal supplement significantly (p < 0.01) increased the heat stress-induced reduction in the expression pattern of these three genes (0.65, 0.61, and 0.61-fold change, respectively). Therefore, from this study, it could be concluded that although the herbal supplements did not bring positive changes in body weight and allometric measurements, it still had a beneficial impact on the endocrinology and genes governing growth performance in Kenguri ewes. Thus, the herbal feed additive used in the study shows promise for relieving heat stress in Kenguri ewes.