Response of immune system and microbial content of gut to feeding with different levels of crushed laurel leaves (Laurus nobilis) in broiler chickens


This experiment aimed to study the effect of dietary inclusion of different levels of crushed laurel leaves (Laurus nobilis) on the immune responses and microbial content of gut in broiler chickens. A total of 180 unsexed one-day-old broiler chickens were randomly divided into four treatments (45 birds per treatment) and each treatment consisted of three replicates (15 birds per replicate). The treatment groups were: control; without adding crushed laurel leaves to the diet, second treatment; Adding 1 g/kg feed crushed laurel leaves to diet, third treatment: Adding crushed laurel leaves with amount of (2 g / kg feed) and treatment Fourth: Adding crushed laurel leaves with amount of (3 g / kg feed). The experiment included the following traits: antibody titer against Newcastle disease, investigating sensitivity against Newcastle disease, the relative weight of bursa of Fabricius, bursa of Fabricius index, estimating the total number of bacterial, estimating the total number of coliform bacteria and estimating the total number of Lactobacillus bacteria. The results indicated that adding the crushed laurel leaves significantly improved cellular immunity and antibody titer against Newcastle disease as well as relative weight of bursa of Fabricius and bursa of Fabricius index. A significant decrease in the logarithmic numbers for the total aerobic bacteria and coliform bacteria with a significant increase in the logarithmic numbers for Lactobacillus bacteria in the duodenum contents for the small intestine as well as in the ceca compared to the control treatment. It is concluded that the addition of crushed laurel leaves to the diet can improve the immune response and microbial content of digestive tract in broiler chickens.


  • Admas S (2016) Review of Biological Impacts of Genetically Engineered Crops and Neonicotinoid Treated Seed Use on Staten Island. International Journal of Biotechnology, 5(4): 62-68.
  • Ali NA, Fadhil RA, Imad A, AL- Nassry AS (2019) Effect of adding white tea powder (camellia Sinensis) to the ration in the qualitative traits of Japanese quail eggs (Coturnix coturnix japonica). Bioscience Research 16(1): 459-464. Retrieved from
  • Ali NAL, Mamdooh GAAKD, AL-Nasrawi AM (2016) Effect of Addition Different Levels of Parsley Leaves Powder (petroselinum sativum) to the Ration on Some Blood Serum Biochemical Traits of Broiler Ross 308. Journal of Natural Sciences Research 6(20): 18-21.
  • Al-Shahat, NAZ (2000) Plants and medicinal herbs. Second Edition, Arab Publishing House. Cairo.
  • Al-Sheikhly FI (2003) Poultry Diseases. Second Edition. Atlas Company for Printing. Baghdad.
  • Alshukri AY, Ali NAL, Abbas RJ, Alkassar AM, Jameel YJ Effect of Dietary Supplementation with Differing Levels of Moringa oleifera Leaf Meal on the Productivity and Carcass Characteristics of Broiler Chickens.
  • APHA (American Public Health Association). (1978) Standard Methods for the Examination of Dairy Products.14th Ed. Marth. E.H. (Ed) American Public Health Association. USA, Washington, D.C.
  • Baytop T (1999) Therapy with Medicinal Plants in Turkey: Past and Present [in Turkish], İstanbul, Nobel Publications.
  • Bulbul T, Vural O, Aziz B (2015) Use of sage (Salvia triloba L.) and laurel (Laurus nobilis L.) oils in quail diets, Eurasian Journal of Veterinary Sciences 31(2): 95−101.
  • Erturk O, Ozbucak TB, Bayrak A (2006) Antimicrobial activities of some medicinal essential oils. Herba Polonica 52(1/2): 58-66.
  • Fdam EMA, Nafia HH, Hussein FM (2016) Effect of Supplementation crushed Melissa officinalis and laurus nobilis leaves and artificial antioxidant to broiler diets on Productive characteristics of broiler. Anbar Journal of Veterinary Science 9(1): 31-40. Retrieved from
  • Karaalp M, Genc N (2013) Bay laurel (Laurus nobilis L.) in Japanese quails feeding. 2. Fatty acid content and oxidative stability of breast meat. Bulgarian Journal of Agricultural Science 19(3): 606-610.
  • Kivcak B, Mert T (2002) Preliminary evaluation of cytotoxic properties of Laurus nobilis leaf extracts. Fitoterapia 73: 242-243. Retrieved from
  • Makki Al Rubaee MA (2018) Effect of bay laurel (Laurus nobilis L.) leaf powder dietary supplementation on dressing percents, carcass trait, carcass cuts and some internal organs of meat type quail. Indian Journal of Science and Technology 11(37).
  • Mukhtar F, Chisti H (2018) The Study of Heavy Metals in Sediments Sampled from Dal Lake. Journal of Environmental Treatment Techniques, 6(2): 33-35.
  • Musa K, Mahfuz E, Nusret G, Metin S, Musa Y, Mehmet O (2011) Bay Laurel (Laurus nobilis L.) in Japanese quails feeding 1. Performance and egg quality parameters. Journal of Animal and Veterinary Advances 10(4): 1883-1889.
  • National Research Council (NRC). (1994) Nutrient requirement of poultry then. National Academy Press. Washington, D. C. USA.
  • Nazia MAC, Perween T (2006) Bactericidal Activity of black pepper, bay leaf, aniseed and coriander against oral isolates. J. Pharm. Sci 19(3): 214-216. Retrieved from
  • SAS (2010) SAS/ STAT Users Guide for Personal Computers Release 9.1 SAS. Institute Inc. Cary and N.C USA. Retrieved from
  • Speak M (1984) Compendium of Method for the Microbiological Examination for Food. 2nd Ed. Washington, D.C. USA.
  • Voller A, Bidwell DE, Bartlett A (1977) The Enzyme-Linked Immunosorbent Assay (ELISA): 24-26. Flow-line Publications, Guernsey. Retrieved from
  • D8%AA%D9%86.pdf


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