Abstract
Necrotic enteritis instigated by Clostridium perfringens is a foremost health and financial problem in poultry. Conventional antimicrobials such as metronidazole provide partial control, but concerns over drug resistance and residues have encouraged the use of natural adjuncts like flaxseed oil, which has hepatoprotective and immunomodulatory properties.
125 broiler chicks existed reared under standard husbandry conditions and vaccinated against common viral diseases. At 15 days of age, birds were stressed by Eimeria necatrix oocysts and challenged orally by C. perfringens type A. They were randomly assigned to five groups: negative control, infected untreated, infected treated with metronidazole, infected treated with metronidazole plus flaxseed oil (therapeutic), and infected prophylactically supplemented with flaxseed oil plus metronidazole. Clinical signs, mortality, bacterial counts, serum biochemical parameters, immunological markers, and metronidazole residues were assessed.
Infected untreated birds exhibited typical necrotic enteritis signs, increased mortality, higher intestinal bacterial counts, elevated hepatic and renal markers, and reduced protein fractions, particularly albumin. Metronidazole treatment partially improved outcomes, while its combination with flaxseed oil enhanced recovery of biochemical and immunological parameters. Prophylactic flaxseed supplementation produced the best results, with minimal clinical signs, zero mortality, lowest bacterial counts, near normal biochemical values, and significant downregulation of IL 1β expression. Importantly, metronidazole residues declined rapidly in all tissues, with flaxseed supplementation accelerating clearance. Birds receiving prophylactic flaxseed reached below detection limits earlier, ensuring food safety.
C. perfringens infection disrupts liver and kidney function and induces hypoproteinemia in broilers. Flaxseed oil, particularly when used prophylactically, enhances clinical recovery, immune modulation, and accelerates drug residue clearance, supporting its role as a natural adjunct to antimicrobial therapy in poultry production.

Key words: Necrotic enteritis, Linseed oil, Clostridium perfringens, poultry, Metronidazole