Poultry is one of the lucrative food industries worldwide (Oso et al., 2021). The livestock industry faces many challenges for achieving higher productivity because of the increasing demand for animal protein (Vargas et al., 2025). Any nation’s economic development is significantly influenced by the poultry industry (Singh et al., 2020 and Devi et al., 2024). There has been a recent surge in the poultry sector for the complete removal of antibiotics from the animal and poultry production systems (Sheoran et al., 2018). Phytogenic feed additives such as clove (Syzygium aromaticum) and tulsi (Ocimum sanctum) are widely recognized for their rich phytochemical composition, including ursolic acid, eugenol and rosmarinic acid. These bioactive compounds exhibit antioxidant, antimicrobial and anti-inflammatory properties, which contribute to improved growth performance and immunity in broiler chickens. The increasing concern over antibiotic resistance has resulted in the search for the natural alternatives in poultry production. Medicinal plants like tulsi and clove possess antimicrobial, antioxidant and immunomodulatory properties that can enhance broiler performance. Although the individual effects of clove and tulsi are well documented, studies on their combined supplementation remain limited, but indicate potential synergistic benefits. Therefore, the present study evaluated the combined effect of tulsi and clove on performance, growth, immunity, carcass traits and blood parameters in broiler chickens.

The study was carried out after obtaining due Ethical Approval vide no. 433/GO/Re/S/01/CCSEA of the Institutional Ethical Committee (IEC). A total of 120 day-old Vencobb broiler chicks were distributed randomly into four treatment groups viz. T₁ (Basal diet), T₂ (Basal diet +1% tulsi powder), T₃ (Basal diet +1% clove powder) and T₄ (Basal diet + 0.5% tulsi + 0.5% clove powder) with each group comprising three replicates of 10 birds. Basal diets were formulated according to BIS (2007) recommendations for pre-starter (1-14 days), starter (15-21 days) and finisher (22-35 days) phases (Table 1 and Table 2). Feed and water were given ad libitum throughout the experimental period.





Tulsi leaves and clove buds were procured from the local market, sun-dried, ground into powder and incorporated into the feed as per treatment levels (Table 3). Birds were reared under standard deep litter management.



At 35 days of age, six birds from each treatment were slaughtered for blood and carcass evaluation. Blood samples were collected for haematological and biochemical analyses. Serum glucose, cholesterol, triglycerides, total protein, albumin, calcium and phosphorus were estimated. Haemoglobin (Hb), total erythrocyte count (TEC) and packed cell volume (PCV) were determined using standard laboratory methods. Cell-mediated immunity was assessed using the Phyto haemagglutinin-P (PHA-P) induced cutaneous basophil hypersensitivity (CBH) test. Humoral immunity was evaluated by haemagglutination (HA) test following antigen administration. Five birds per treatment were slaughtered to evaluate carcass traits, including dressing percentage, eviscerated yield and cut-up parts (breast, thigh, drumstick, wings, back and neck).

The data were statistically analyzed using one-way ANOVA in SPSS (version 16.0) at P<0.05 significance level.

Effect on body weight
 
Dietary supplementation significantly influenced growth performance of broiler chickens. Body weight did not differ among groups at the initial stage (P>0.05). However, from the first week onwards, supplemented groups showed higher body weight compared to control. By 5th week, the highest body weight was noted in T₄ (1770.90±21.84 g), followed by T₂, T₃ and T₁, respectively. The combined supplementation (T₄) showed significantly (P<0.05) higher body weight than other groups. The present study demonstrated a notable influence of dietary supplementation on body weight of broiler chicks. During the first week, the highest body weight was noted in the T₂ group, followed by a continued increase in the second week. However, no discernible differences were recorded during the third week. By the fourth week, birds in the T₄ group exhibited significantly (P<0.05) higher body weight as compared to other treatment groups. At the end of the experimental period, T₄ (mixture of tulsi and clove @0.5%) showed significantly higher body weight than the control, tulsi (1%) and clove (supplemented 1%) groups. The improved growth performance may be attributed to enhanced secretion of digestive enzymes, improved nutrient absorption and neutralization of harmful bacterial toxins and gastric acids. These findings were in line with Vasanthakumar et al., (2013), who observed the increased feed intake with 0.5% tulsi supplementation. Similarly, Arif et al., (2022) observed significantly higher weight gain in birds supplemented with a combination of aloe vera and clove. Bhosale et al., (2015) also reported improved weight gain with tulsi leaf powder supplementation. The beneficial effects of tulsi may be linked to its bioactive compounds such as eugenol, apigenin, cirsilineol and cirsimaritin, which possess antioxidant and antimicrobial properties (Hossain et al., 2021). The supplementation of Clove may enhance amino acid utilization by reducing their degradation, thereby promoting growth.
 
Effect on feed intake and feed conversion ratio (FCR)
 
The cumulative feed intake increased with age and differed significantly (P<0.01) among treatments. The highest feed intake was observed in T₃, followed by T₄ and T₂, while the control group recorded the lowest intake, which indicated that tulsi and clove supplementation enhanced feed palatability and nutrient utilization efficiency. Feed conversion ratio (FCR) significantly improved (P<0.05) in supplemented groups (Table 4). The best FCR was observed in T₄ (1.62±0.02), followed by T₂, indicating better feed efficiency with combined tulsi and clove supplementation. These findings are consistent with Dalkilic and Guler (2009), who reported improved FCR with 400 ppm clove supplementation. Arif et al., (2022) also observed significantly better FCR in birds receiving combined herbal supplementation. Similarly, Bhosale et al., (2015) reported a significantly lower FCR (P<0.05) in birds supplemented with tulsi leaf powder and vitamin E compared to the basal diet group.


 
Effect on hematological parameters
 
The hemoglobin (Hb), total erythrocyte count (TEC), packed cell volume (PCV), mean corpuscular hemoglobin concentration (MCHC) and mean corpuscular volume (MCV) did not vary significantly (P>0.05) among the treatment groups. All values remained within normal physiological ranges. These findings were in agreement with Biswas et al., (2020) and Kohri et al., (2022), who also reported no significant changes in blood parameters with tulsi supplementation. Kaswan and Dhuria (2022) similarly observed non-significant differences in most hematological parameters across treatment groups, with values remaining within normal physiological ranges. In contrast, Hasan et al., (2016) reported a significant (P<0.05) increase in erythrocyte count and PCV, while Sultana et al., (2023) observed significant changes in MCH, but not in MCV. Overall, normal hematological values indicate adequate nutritional status and physiological well-being of the birds (Church et al., 1984).
 
Effect on serum biochemical parameters
 
Serum biochemical parameters showed selective responses to dietary treatments. Glucose, albumin and urea levels remained unaltered. However, total protein and globulin levels were significantly (P<0.05) higher in T₃ and T₄ (Table 5). The levels of serum cholesterol and triglyceride were significantly reduced (P<0.01) in all supplemented groups as compared to control, with the lowest triglyceride levels observed in T₃. Dietary supplementation with tulsi and clove did not significantly affect serum glucose, albumin, or urea levels; however, total protein levels showed a significant increase. These findings aligned with Tanwar et al., (2021), who reported elevated total protein and glucose levels in supplemented birds. A significant (P<0.05) reduction in the levels of triglycerides and cholesterol was observed in supplemented groups. Similarly, Tanwar et al., (2021) reported reductions in lipid fractions. Tulsi exhibits hypolipidemic effects due to bioactive compounds such as eugenol, which may inhibit cholesterol synthesis (Saxena et al., 2019). The combination of tulsi and clove may exert synergistic effects, resulting in enhanced lipid-lowering activity (Singh et al., 2020).


 
Effect on immune status
 
Both humoral and cell-mediated immune responses were significantly enhanced (P<0.01) by supplementation. The highest antibody titre and CBH response were recorded in T₄, then in T₂ and T₃, with lowest values were noted in the control group (Table 6). The study demonstrated a significant improvement in immune response, as evidenced by increased footpad swelling following PHA-P injection, indicating enhanced cell-mediated immunity. This response may be attributed to increased T-lymphocyte activity and improved antigen recognition. Additionally, higher antibody titers suggested enhanced humoral immunity in supplemented birds. These findings are supported by Singh and Doley (2014), who reported improved humoral and cell-mediated immune responses with increasing levels of tulsi supplementation. Tulsi possesses immunomodulatory properties, stimulating antibody production and immune cell activation due to compounds such as eugenol (Saxena et al., 2019). Clove also exhibits immunostimulatory effects, enhancing immune responses through similar mechanisms (Al-Daraji et al., 2018).


 
Effect on carcass characteristics and organ weights
 
Dressing percentage was significantly (P<0.05) higher in T₄ and T₂ as compared to control. Back yield also showed significant improvement in supplemented groups (Table 7). However, other carcass traits such as neck, wing, breast and thigh yields remained unaffected. The relative weights of internal organs (liver, kidney, gizzard and heart) were not significantly influenced (P>0.05) by dietary treatments, indicating no adverse effect on organ development. A significant improvement was observed in carcass traits such as dressing percentage and back yield. However, Sultana et al., (2023) observed improved muscle fiber development and increased breast and thigh yield at specific inclusion levels of tulsi and clove. Mohata et al., (2020) also reported significant improvements in eviscerated weight with tulsi supplementation.



The organ weights (heart, liver, kidney and gizzard) were not significantly affected by dietary treatments (Table 8), which was in line with the reports of Vasanthakumar et al., (2013). However, Gandomani et al., (2014) noted increased splenic weight at higher clove inclusion levels, indicating possible immunological stimulation.

The bioactive compounds like tulsi, clove, etc. exhibit antimicrobial, anti-inflammatory and antioxidant properties, which contribute to improved growth performance, immunity and metabolic functions in birds. The increasing concern over antibiotic resistance has led to the search for natural alternatives in poultry production. In the present study, the birds in T4 showed significantly (P<0.05) higher body weight and better feed conversion ratio (FCR) than control. Serum cholesterol and triglycerides were significantly reduced in supplemented groups, while immune responses were enhanced. Hematological parameters and organ weights were unaffected. Therefore, it can be concluded that the combined tulsi and clove supplementation in T4 group of broiler birds fed a Basal diet and 0.5% each of tulsi and clove powder significantly improved the growth, lipid profile and immunity in broiler chicken.

The Authors and Co-authors are indebted to the Dean, CVSc. and A.H., OUAT, Bhubaneswar for providing necessary amenities, facilities for the successful completion of this research work in time.

There exists no conflict of interest among the authors.