Evaluation of a Photobiotic blend as a natural alternative to antibiotic growth promoters in broiler chickens

Introduction

The increasing global population has intensified the demand for affordable and high-quality sources of animal protein. Among the various livestock products, broiler chicken meat is recognized as one of the most economical and efficient sources of dietary protein. Consequently, the poultry industry has undergone rapid expansion and commercialization over the past few decades. However, intensive broiler production systems are frequently associated with several challenges, including increased disease susceptibility, reduced immune competence, environmental stress, poor growth performance, and economic losses resulting from higher mortality. To improve growth performance and production efficiency, synthetic growth promoters and various chemical feed additives have traditionally been incorporated into broiler diets. Although these additives have contributed to enhanced growth and feed utilization, their prolonged use is associated with several limitations, including increased production costs, adverse effects on bird health, and the risk of chemical residues in poultry products (Bhujbal et al., 2009) [3]. In addition, antibiotic growth promoters (AGPs) have long been used to improve growth rate, feed efficiency, and overall productivity in broiler production. However, the continuous use of AGPs has raised serious concerns regarding the emergence of antimicrobial-resistant bacteria and the presence of antibiotic residues in poultry products. These concerns pose significant risks to both animal and public health, leading to restrictions on the routine use of AGPs in several countries and encouraging the search for safer and sustainable alternatives. Among the available alternatives, phytobiotics, also known as phytogenic feed additives, have gained considerable attention as natural substitutes for antibiotic growth promoters. These plant-derived bioactive compounds contain a diverse range of secondary metabolites, including www.extensionjournal.com essential oils, flavonoids, alkaloids, tannins, saponins, and phenolic compounds, which possess antimicrobial, antioxidant, anti-inflammatory, antiviral, and immunomodulatory properties. By maintaining a balanced intestinal microflora (eubiosis), phytobiotics improve nutrient digestion and absorption, stimulate digestive enzyme secretion, enhance feed utilization, and strengthen the immune system. These combined effects ultimately improve growth performance, feed conversion efficiency, and the overall health status of broiler chickens. Several medicinal plants have been extensively investigated for their growth-promoting and therapeutic potential in poultry production. Supplementation of tulsi (Ocimum sanctum) has been reported to improve body weight gain, feed intake, feed efficiency, and overall growth performance in broilers (Islam et al., 2013; Hasan et al., 2016) [9,6] . These beneficial effects are likely attributable to the antimicrobial and antiprotozoal properties of tulsi (Kale et al., 2003) [12] , which help reduce the intestinal microbial load, thereby improving nutrient utilization, feed consumption, and overall feed efficiency (Pushpagadan and Sobti, 1977) [17] . Dietary supplementation with turmeric (Curcuma longa) has also been shown to improve feed conversion ratio and promote growth performance (Zeinali et al., 2009) [22] . Likewise, Nigella sativa supplementation has been reported to increase body weight gain, enhance immune response, and reduce plasma cholesterol concentration in poultry (Durrani et al., 2007; Hassan et al., 2004) [4,7] . Other medicinal plants, including neem (Azadirachta indica), ashwagandha (Withania somnifera), aloe vera (Aloe barbadensis), and punarnava (Boerhavia diffusa), have also demonstrated beneficial effects owing to their antimicrobial, antioxidant, and immunomodulatory activities. Their bioactive constituents help suppress pathogenic microorganisms, reduce oxidative stress, maintain intestinal integrity, and improve nutrient utilization, thereby enhancing productive performance in poultry. Considering the growing concerns regarding antibiotic growth promoters and the increasing consumer demand for safe and residue-free poultry products, the evaluation of herbal feed additives under farmers' field conditions has become increasingly important. Therefore, the present study was undertaken to evaluate the efficacy of a phytobiotic blend comprising neem leaves, tulsi leaves, turmeric rhizomes, ashwagandha roots, Nigella sativa, aloe vera, and punarnava roots included in the diet at 2% on growth performance, feed conversion ratio, mortality, and economic efficiency in broiler chickens under farmers' field conditions.

Materials and Methods

The present on-farm trial was conducted in Chandauli district, Uttar Pradesh, India, to evaluate the effect of a phytobiotic mixture on the productive performance of broiler chickens under farmers' field conditions. Five poultry farms were selected for the study. A total of 1000 day-old commercial broiler chicks were equally distributed among the five farms. Within each farm, birds were randomly allocated into two experimental groups: a control group (T₁) and a treatment group (T₂), comprising 100 birds per group. Thus, each treatment consisted of a total of 500 birds across all farms. Birds in both groups were managed according to the feeding and management practices recommended by the Bureau of Indian Standards (BIS). The birds in the control group (T₁) were fed a standard commercial broiler diet without any supplementation, whereas those in the treatment group (T₂) received the same basal diet supplemented with a phytobiotic mixture at 2% of the diet throughout the experimental period. The phytobiotic mixture consisted of neem leaves (Azadirachta indica), tulsi leaves (Ocimum sanctum), turmeric rhizomes (Curcuma longa), ashwagandha roots (Withania somnifera), Nigella sativa, aloe vera (Aloe barbadensis) and punarnava roots (Boerhavia diffusa). All birds were reared under a deep litter system with ad libitum access to feed and clean drinking water throughout the experimental period. Uniform management practices, including the recommended vaccination schedule, were followed for both experimental groups. Strict biosecurity measures were implemented to minimize the risk of disease. Before chick placement, the poultry houses were thoroughly cleaned and disinfected, followed by fumigation using formalin and potassium permanganate (KMnO₄). Feeders, drinkers, and all other equipment were cleaned, disinfected, and sanitized before use. During the trial, feeders and drinkers were disinfected daily with 0.02% potassium permanganate (KMnO₄) solution, and lime powder was maintained at the entrance of each poultry shed to reduce microbial contamination. The experiment was conducted to evaluate the effect of dietary phytobiotic supplementation on growth performance, feed conversion ratio (FCR), mortality and economic efficiency of broiler chickens under farmers' field conditions. The experimental data were analyzed using the Statistical Package for the Social Sciences (SPSS) software. Statistical significance was declared at p < 0.05.

Results and Discussion-

The effect of dietary supplementation of a 2% phytobiotic mixture on the productive performance of broiler chickens under farmers' field conditions is presented in Table 1. The results demonstrated that supplementation of the phytobiotic blend significantly improved growth performance, feed efficiency and economic efficiency without adversely affecting bird health. The average initial body weight of chicks did not differ significantly (p > 0.05) between the control (41.00±0.63 g) and treatment (43.00±0.82 g) groups, indicating that chicks were uniformly distributed at the commencement of the experiment. Thus, the observed differences in productive performance at the end of the trial can be attributed primarily to the dietary supplementation of the phytobiotic mixture rather than to any initial variation in body weight. Dietary supplementation of the phytobiotic mixture resulted in a significant (p < 0.05) improvement in growth performance. Broilers receiving the phytobiotic blend attained a significantly higher final body weight (2299.92±16.73 g) compared with the control birds (2189.88±14.22 g), representing an increase of approximately 5.02% in live body weight. Likewise, the average daily gain was significantly (p < 0.05) greater in the treatment group (54.76±0.40 g) than in the control group (52.14±0.34 g). The improved growth performance observed in the present study may be attributed to the www.extensionjournal.com synergistic action of bioactive phytochemicals present in the herbal mixture, which stimulate digestive enzyme secretion, improve intestinal morphology, maintain a favourable gut microbial ecosystem and enhance nutrient digestion and absorption. In addition, phytobiotics possess antioxidant, antimicrobial and anti-inflammatory properties that reduce oxidative stress and improve metabolic efficiency, thereby promoting better growth and body weight gain in broiler chickens. Mortality was numerically lower in the phytobiotic-supplemented birds (3.00±0.32%) than in the control group (3.60±0.40%); however, the difference was statistically non-significant (p > 0.05). The lower mortality recorded in the treatment group may be associated with the immunomodulatory and antimicrobial activities of phytobiotics, which help improve disease resistance and maintain gut health under field conditions. Although the reduction was not statistically significant, the trend suggests that phytobiotic supplementation may contribute to improved flock health and survivability under commercial production systems. Feed conversion ratio (FCR) was significantly (p < 0.05) improved following phytobiotic supplementation. Birds receiving the phytobiotic mixture recorded a lower FCR (1.56±0.01ᵇ) than those in the control group (1.60±0.01ᵃ), indicating superior feed utilization efficiency. Improved FCR reflects the enhanced ability of birds to convert feed nutrients into body mass. This improvement is likely due to increased digestive efficiency, stimulation of digestive enzyme activity, improved intestinal absorptive capacity and suppression of pathogenic microorganisms and better maintenance of intestinal integrity by phytogenic bioactive compounds. Enhanced feed efficiency ultimately contributes to higher production efficiency and reduced feed cost per unit of body weight gain. Economic analysis further revealed that supplementation of the phytobiotic mixture substantially improved profitability. Similarly, the benefit: Cost (B:C) ratio was significantly (p < 0.05) higher in the treatment group (1.25±0.01ᵃ) than in the control group (1.22±0.01ᵇ). The higher B:C ratio clearly demonstrates that the additional expenditure incurred on phytobiotic supplementation was effectively compensated by improved growth performance and feed efficiency, thereby improving the economic efficiency of broiler production. These findings indicate that dietary supplementation of phytobiotics is not only biologically effective but also economically viable under farmers' field conditions. The findings of the present investigation are in close agreement with those reported by Javed et al. (2009), who observed significantly higher body weight gain, dressing percentage, breast weight and leg weight in broilers supplemented with herbal formulations containing Withania somnifera (Ashwagandha). Similarly, Srivastava et al. (2013) [20] reported significant improvements in dressing percentage following herbal supplementation. The enhanced growth performance observed in the present study is also consistent with the reports of Prajapat et [16,15,2] who attributed improved body weight gain to enhanced digestive activity, improved nutrient absorption, antimicrobial effects and antioxidant properties of phytogenic feed additives. The numerical reduction in mortality observed in the present investigation corroborates the findings of Eevuri and Putturu (2013) [5] , who reported improved survivability in broilers supplemented with Aloe vera. The immunomodulatory, antibacterial, antiviral and antioxidant properties of phytobiotics may collectively contribute to improved health status and lower mortality under field conditions. Similar improvements in body weight gain and feed efficiency have also been reported by Mohamed et [14,8,3,10,19,1] , who demonstrated that supplementation of turmeric, ginger, basil and polyherbal mixtures significantly enhanced broiler performance. Furthermore, the significant improvement in FCR observed in the present study agrees with the findings of Urusan and Bolukbas (2017) [21] , whereas the enhanced economic efficiency are in accordance with the observations of Rawat et al. (2016) [18] , who reported improved profitability following supplementation of phytobiotics and organic acids in broiler diets. Overall, the present findings clearly demonstrate that supplementation of a 2% phytobiotic mixture effectively improved growth performance, feed utilization efficiency and economic efficiency under farmers' field conditions. The results suggest that phytobiotic supplementation can serve as a promising, safe and economically viable alternative to antibiotic growth promoters for sustainable broiler production.

Conclusions

The findings of the present on-farm trial demonstrated that dietary supplementation of a 2% phytobiotic mixture significantly improved the productive performance and economic efficiency of broiler chickens under farmers' field conditions. Birds receiving the phytobiotic-supplemented diet exhibited significantly higher average daily gain and final body weight, along with a significantly lower feed conversion ratio and a significantly higher benefit-cost (B:C) ratio than those fed the conventional diet. Although the reduction in mortality was not statistically significant, a favourable numerical decline was observed in the treatment group. The improved growth performance, feed efficiency and higher benefit-cost (B:C) ratio indicate the economic viability of phytobiotic supplementation. Overall, the study suggests that incorporation of a 2% phytobiotic mixture in broiler diets can be recommended as a safe, effective and economically sustainable feeding strategy to enhance productivity under field conditions. Furthermore, phytobiotic supplementation offers a promising natural alternative to antibiotic growth promoters, www.extensionjournal.com thereby supporting sustainable poultry production and addressing the increasing demand for antibiotic-free broiler meat.

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