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Hydroxamic Acid Isolated from Maize Roots Exhibits Potent Antimicrobial Activity Against Pathogenic Escherichia coli in Broiler Chickens

Year: 2025

Type: article

Abstract: Restrictions on adding antibiotics to animal diets have posed challenges in managing gut pathogens, emphasizing the significance of effective non-antibiotic growth promoters to maintain animal health and productivity. This study assessed the efficacy of hydroxamic acid (HA), derived from local maize varieties, as a non-antibiotic growth promoter in broilers. Among 10 different maize varieties, the Azam variety yielded the highest HA concentration (35 ± 7 μg/g of roots), as quantified by high-performance liquid chromatography (HPLC). In vitro antimicrobial assays demonstrated the lowest minimum inhibitory concentration (MIC) of 0.022 mg for Azam-derived HA against pathogenic E. coli. To further assess in vivo efficacy, 108 birds were allocated at random to six treatment groups. The treatments include birds fed a basal diet without an E. coli challenge (negative control); an antibiotic-treated group challenged with E. coli and treated with enrofloxacin at a dosage of 5 milligrams (mg) per kilogram (kg), administered orally once daily from day 5 post-infection (dpi) for 7 consecutive days (standard); broilers challenged with E. coli and supplemented with a basal diet with HA at concentrations of 1, 10, or 100 mg/kg of feed from 5 dpi for one week (HA 1 mg, HA 10 mg, and HA 100 mg, respectively); and broilers challenged with E. coli without enrofloxacin/HA (positive control). The results demonstrated that birds fed a diet supplemented with the HA-100 mg improved the body weight (BW) and feed conversion ratio (FCR) compared to the positive control group. There were no significant differences (p > 0.05) observed for BW and FCR observed for the broilers fed on the standard and HA 100 mg groups. The addition of HA at 100 mg improved (p < 0.05) the hemoglobin (Hb) and packed cell volume (PCV) and reduced (p < 0.05) levels of malondialdehyde (MDA) compared to positive control group. A significantly low carcass weight (p < 0.05) was shown for positive control birds compared to other groups. Our findings indicate that maize-derived HA presents a phytogenic alternative to antibiotics by controlling enteric pathogens and improving health and performance affected by E. coli infection in broilers.

Source: Microbiology Research

DOI: 10.3390/microbiolres16100222