Effects of an organic acids blend and coated essential oils on broiler growth performance, blood biochemical profile, gut health, and nutrient digestibility

This study aimed to evaluate the effects of an organic acid blend and essential oils individually and in combination on growth performance, blood biochemical profile, gut health, and nutrient digestibility of broilers fed a higher level of an animal protein concentrate. Five hundred day-old Ross-308 male broiler chicks (average body weight, 39 +/- 1.2 g) were randomly assigned to five replicated (5 replicates/treatment; 20 birds/replica) dietary treatments (100 birds/treatment). Birds in these group were given five different experimental diets that were prepared and designated as (i) basal diet (negative control, NC); (ii) basal diet plus Enramycin (positive control, PC), 50 mg/kg feed; (iii) basal diet with the addition of organic acid (OA) at 200 mg/kg feed; (iv) basal diet plus essential oils (EO) at 150 mg/kg feed; (v) basal diet plus combination of OA and EOs 200 and150 mg/kg feed (OA + EO). Experimental diets were prepared and fed in two phases i.e. starter (1-21 d) and finisher (22-42 d) phases of rearing. The findings of the present study revealed that feed intake did not vary significantly among the treatment groups, however, better (p < .05) body weight gain (BWG) and feed conversion ratio (FCR) was observed in OA, EO and OA + EO supplemented groups, respectively. The growth of Clostridium perfringens, Escherichia coli and Salmonella were reduced (p < .05) in OA, EO, OA + EO groups, while, Lactobacillus growth was positively improved (p < .05). Notably, the intestinal lesion score was significantly reduced, and villus height was improved in the OA, EO, OA + EO groups compared to birds in the NC group. Moreover, the serum level of calprotectin and liver enzymes were significantly reduced in the OA + EO treated group. At the end of the trial five birds from each experimental replicate of all five treated groups were shifted to metabolic cages on day-36 till day-42 for daily excreta collection and euthanized for ileal digesta to asses apparent metabolisable energy AME and nutrients digestibility. All dietary treated groups compered to birds in the NC group enhanced nutrients digestibility and AME. It was deduced that supplementing organic acids and essential oils are beneficial in improving birds performance, health, nutrient digestibility and subsequently could potentially replace antibiotic as growth promoters and could enhance the utilisation of animal protein concentrate without compromising performance and gut health in the poultry feed industry.