Enhanced modulation of gut microbial dynamics affecting body weight in birds triggered by natural growth promoters administered in conventional feed

Abstract

This study explored the effects of natural growth promoters (phytogenic feed additives and organic acids) on animal performance, carcass characteristics, blood parameters, gut microflora composition, and microbe-host interactions in broiler chickens over a 42-day feeding period. Two-hundred-fifty-day-old chicks were randomly assigned to one of five treatments: (i) control diets (CON); (ii) control diets + 40 g/tons antibiotic growth promoter (AB); (iii) control diets + 3 kg/tons organic acids (ORG); (iv) control diets + 3 kg/tons phytogenic feed additives (PHY); (v) control diets + 3 kg/tons organic acids + phytogenic feed additive combination (COM). A non-significant differences (p > 0.05) were observed in broiler performance among treatments at 21 days of age; however, a gradually increasing body weight gain and reduced feed conversion ratio were observed at 42 days in treatments versus control group. Biochemical indices were non-significant (p > 0.05) except for decreased cholesterol (p < 0.05) and increased A/G ratio (p < 0.05) recorded in the treatment groups. The addition of PHY and ORG improved total counts of Enterococcus spp. and Lactobacillus spp. (p < 0.05) as well as reduced caecal and ileal Campylobacter spp. and Escherichia coli (p < 0.05). Correlation analysis elucidated beneficial bacteria (Enterococcus spp. and Lactobacillus spp.) were positively and pathogenic bacteria (Campylobacter spp. and E. coli) were negatively correlated (p < 0.05) with host weight gain. The findings indicated that dietary supplementation of PHY and ORG sustained balanced gut microflora, which in turn improved body weight. This study broadens the significance of using PHY and ORG as safe alternatives to antibiotic growth promoters for achieving healthier and economical broiler production.

Keywords: Broiler; Dietary modulation; Gut microbiota; Organic acids; Phytogenic feed additives; Weight gain.

Fig. 1

Microflora composition (log cfu/g) of study groups in broiler cecum and ileum regions at 42 days. Groups: CON: control, AB: antibiotic growth promoter, ORG: organic acid, PHY: phytogenic feed additives, COM: combination. ^A,B,C Bars (Means ± standard error of mean) with different letters within the same microbial group differ significantly at p < 0.05.

Fig. 2

Gel images of Salmonella spp. detection in cecum (a) and ileum (b) regions of broiler chickens. Groups: CON: control, AB: antibiotic growth promoter, ORG: organic acid, PHY: phytogenic feed additives, COM: combination. “+ve” = Positive control (Salmonella typhimurium, ATCC 14028).

Fig. 3

The relationship between body weight and targeted bacteria (a) Lactobacillus spp., (b) Enterococcus spp., (c) E. coli, and (d) Campylobacter spp. in chickens. Simple linear regression was performed to assess relationship based on Pearson’s correlation coefficient (r) and P values.