Introduction

The world food production is relying more and more on animal source of protein. The broiler industry has become an important economic activity in many countries for the production of meat to balance the human diet. The efficiency of broilers to convert feed into meat plays a key role in economics of broiler industry. In addition, the world poultry sector is also facing the dual challenges of sufficiency and safer production. The use of medicinal plants or herbs as feed additives to promote growth and health is gaining popularity worldwide due to their suitability and preference, low cost of production, reduced risk of toxicity, minimum health hazards and environment friendliness (Owen, 2011).

Withania somnifera popularly called as Indian Ginseng has long been used as an anti-oxidant, adaptogen, aphrodisiac, liver tonic, anti-inflammatory agent, astringent, antibacterial and antifungal agent (Punetha et al., 2010). Various parts of the plant have been reported to possess antiserotogenic and anabolic properties (Prakash et al., 2001). A trial in broilers revealed that W. somnifera root extract effectively reversed enhanced proteolysis and lowered serum protein level and enhanced the serum albumin as well as total protein that never deviated from the normal range throughout the trial period (Udayakumar et al., 2009). An another advanced approach to maximize the utilization of feed stuff is combined use of probiotics and prebiotics in the form of synbiotic which beneficially affects the host by activating the metabolism of one or a limited number of health promoting bacteria and stimulating their growth selectively, improving the host’s welfare (Gibson and Roberfroid, 1995). PER is one of the oldest measures of assessment of efficiency of conversion of dietary protein into body mass. Therefore keeping in view, the anabolic properties of W. somnifera and growth stimulating effect of synbiotic substance, the present study was conducted with the objectives to observe the effect of supplementation of Withania somnifera and synbiotic on protein efficiency ratio in broilers chicks.

Materials and Methods

Day old unsexed Vencobb broiler chicks (N=360) of similar body weight and in good condition were procured from commercial hatchery. The Withania root powder and synbiotic in sufficient quantity were procured from local market. The readymade broiler starter and finisher feed were procured from reputed poultry feed manufacturers. The proximate composition of broiler starter, broiler finisher, Withania and synbiotic is presented in Table 1.

Table 1: Proximate composition¹ of broiler starter, broiler finisher, W. somnifera root powder and synbiotic

¹Average of the values determined on samples compounded on three occasions

PER values were calculated during each studied weekly growth period according to equations of Ali (1999) as follows:

The experimental data were subjected to statistical analysis (SPSS Ver. 20.0) using one way analysis of variance to test for significant variation between treatment groups. Probabilities values of less than 0.05 (p<0.05) were considered significant. Comparison of mean values was carried out by Duncan’s Multiple Range Test. The results were interpreted and expressed as means ± pooled SEM.

Table 2: Experimental design for different treatment groups

Results and Discussion

The results on effect of different feed additive and their combination on broiler performance indices of protein efficiency ratio is presented in Table 3. Supplementation of any of the feed additive or their combination significantly increased PER in all the treatments during finisher phase and in most of the treatments during starter phase (p˂0.05) of trial. Moreover, cumulatively this index was highest (p<0.05) in broilers fed 1% and 1.5% ashwagandha root powder than those of control and synbiotic fed groups at the end of 42 day trial. In starter phase, numerically higher but nonsignificant PER variation was recorded in 0.5% Withania fed group (T₂) and T₇ treatment group than control group during first and second week of trial which indicates insufficiency of feed additive quantity in initial two weeks. The comparable decrease in PER of control group and antistress effect of ashwagandha become evident on PER with advancement of age. The cumulative PER varied between 2.50 (T₁) to 2.93 (T₃).

Table 3: Weekly protein efficiency ratio of broilers in different treatment groups

Means in the same row bearing different superscripts are significantly different (p<0.05); C: Control; W S: Withania somnifera; Syn:                Synbiotic

The study is in agreement with the findings of Ashayerizadeh et al. (2011) who also observed higher performance of synbiotic supplemented groups in terms of PER than control broilers in both starter and finisher period however the PER observed in synbiotic supplemented groups was lower than 1% and 1.5% ashwagandha treated broilers (p˂0.05). Similarly, El- Katcha et al. (2014) also reported significant improvement in PER when broiler diets were supplemented with organic growth promoter.  The study is in concurrence with findings of Thakur (2017) who also observed significant anabolic effect of Withania somnifera and synbiotic on growth and performance of broiler chicks.

The PER is affected by the composition of intestinal microflora. The efficiency of protein utilization decreases in the presence of harmful gut bacteria due to increased breakdown of proteins (Mikulec et al., 1999). In the present study, the beneficial effects of synbiotic products and Withania on broiler performance are in agreement with previous studies (Falaki et al., 2010). The synergistic effect of probiotic and prebiotic in synbiotic mixture and their multiplicative effect on PER with the addition of ashwagandha could be due to reduction in count of unfavorable bacteria and corresponding increase in beneficial microflora in the gut (Kumari and Gupta, 2015). The resultant favourable medium in gut with effective increase in absorptive surface area of gut could be responsible for improvement in protein efficiency ratio (Santin et al., 2001). In contrast, Willis et al. (2007) reported that addition of these additives in the broiler ration had no significant effect on growth performance of broiler chickens.

Conclusion

The present study concluded that the supplementation of Withania somnifera or ashwagandha significantly improved PER at 1% level of supplementation with comparable effect of 0.50% Withania+0.05% synbiotic in broilers and could be utilized as growth promoter in broiler farming.

Acknowledgement

The authors are thankful to Dean, College of Veterinary and Animal Science, Bikaner, RAJUVAS, for providing infrastructure and necessary facilities.

References

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