Abstract

Background:
Heat stress is a key challenge faced by sheep production in arid/semi-arid areas, with implications for metabolic capacity and function, productivity, and immunity. Nutritional interventions (including the incorporation of bioactive compounds such as β-glucan, vitamin C, and zinc) for adaptive adaptation have been suggested to mitigate stress-related physiological derangements.

Aim:
This study aimed to undertake a comparative assessment of the beneficial effects of dietary supplementation with β-glucan, vitamin C + zinc, and their combination on productive performance, hematologic and biochemical characteristics, physiological parameters, and hormonal levels of heat-stressed Awassi rams.

Methods:
Twenty-four adult Awassi rams (1.5 years old; 55 ± 1 kg) were randomly allocated to four treatment protocols, namely, Control, β-glucan (4 g/kg body weight /day), vitamin C + zinc (100 mg + 200 mg/day), and β-glucan + vitamin C + zinc. The summer trial covered 90 days. Laboratory procedures were used to assess productivity traits, hematological indices, biochemical markers, stress physiological measures, and hormone levels.

Results:
Supplementation was associated with significantly greater efficacy in promoting growth, maintaining hematological morphology, and maintaining biochemical and hormonal balance than the control group. The effect was most pronounced for the combined β-glucan + vitamin C and zinc treatment, with maximal body weight (72.5 ± 1.13 kg), growth rate (26.97 %), feed efficiency (feed conversion ratio 3.13), and increase in the hematological indices (red blood cells 10.73 × 10⁶/μl; white blood cells 10.7 × 10³/μl). Biochemical indices showed reduced glucose, cholesterol, triglycerides, and liver enzymes, as well as elevated protein fractions and antioxidant status. Hormonal analysis showed lower cortisol and increased levels of anabolic hormones (T3, T4, and growth hormone). Taken together, these findings suggest that increased supplementation acts as an interplay tool to improve physiological resilience and overall productivity among heat-stressed Awassi rams by enhancing metabolic efficiency.

Conclusion:
When β-glucan, vitamin C, and zinc were included, the greatest improvement in growth performance, physiological stability, biochemical status, and hormonal balance was recorded in heat-stressed Awassi rams. Combining these supplements improved metabolic efficiency, immune function, and stress resilience far more than individual treatments alone. Thus, this nutritional strategy is effective in improving the health and productivity of
thermally stressed animals.

Key words: β-Glucans; Biochemical traits; Rams; Vit C; Zinc.