Effects of dietary thyme essential oil on hemato-immunological indices, intestinal morphology, and microbiota of Nile tilapia
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Thyme (Thymus vulgaris) essential oil (TVEO) is a herbal medicine with one of the highest levels of antimicrobial activity. Although TVEO has been broadly used in poultry and swine production due to its immunostimulatory and growth-promoting characteristics, the effects of TVEO on fish are poorly characterized. In this study, Nile tilapia (Oreochromis niloticus L.) were fed 0, 0.1, 0.5, and 1% TVEO for 15 days. Subsequently, blood parameters, intestinal morphology, and the population of Bacillus bacteria in the intestine were evaluated. The numbers of lymphocytes (p < 0.05) and leukocytes (p < 0.05) significantly increased in the blood of the fish fed the highest dose of TVEO. Based on the normal behavior of the fish and the alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, which were not altered (p > 0.05), this study concluded that the diets were safe and showed no negative or toxic effects. Even at doses as high as 1%, TVEO did not alter the population of beneficial Bacillus bacteria in the gut. In conclusion, supplementation with TVEO stimulated the cellular components of the non-specific immune response of Nile tilapia without causing deleterious effects or altering the population of important intestinal bacteria.
KeywordsBacillus Herbal medicine Immunostimulant Innate immunity Plant extract
The authors thank Dra. Vany P. Ferraz (Chromatography Laboratory, Department of Chemistry, UFMG) for the assistance with the analysis of the EOs. The manuscript was edited for proper English language, grammar, punctuation, spelling, and overall style by one or more of the highly qualified native English speaking editors at American Journal Experts.
This work was supported by grants from the National Council for Scientific and Technological Development-CNPq (140487/2014-0), and the São Paulo Research Foundation-FAPESP and the Coordination of Superior Level Staff Improvement-CAPES (2014/14039-9).
Compliance with ethical standards
The experiment was approved by the Ethics Committee on the Use of Animals (CEUA) of the School of Agricultural Sciences and Veterinary Medicine at Universidade Estadual Paulista (UNESP), Jaboticabal, SP, Brazil, under protocol number 13019/15. The approval was consistent with the ethical principles adopted by the Brazilian College of Animal Experimentation.
Conflict of interest
The authors declare that they have no conflict of interest.
- Abdollahzadeh E, Rezaei M, Hosseini H (2014) Antibacterial activity of plant essential oils and extracts: the role of thyme essential oil, nisin, and their combination to control Listeria monocytogenes inoculated in minced fish meat. Food Control 35:177–183. https://doi.org/10.1016/j.foodcont.2013.07.004 CrossRefGoogle Scholar
- Al-Sagheer AA, Mahmoud HK, Reda FM, Mahgoub SA, Ayyat MS (2017) Supplementation of diets for Oreochromis niloticus with essential oil extracts from lemongrass (Cymbopogon citratus) and geranium (Pelargonium graveolens) and effects on growth, intestinal microbiota, antioxidant and immune activities. Aquac Nutr 24:1006–1014. https://doi.org/10.1111/anu.12637 CrossRefGoogle Scholar
- AOAC (2006) Official methods of analysis, 18th edn. Association of Official Analytical Chemists, GaithersburgGoogle Scholar
- Ellis AE (1990) Lysozyme Assays. In: Stolen JS, Fletcher TC, Anderson DP, Roberson BS, Muiswinkel WB (eds) Techniques in fish immunology. Sos Publications, California, pp 101–103Google Scholar
- FAO (2016) The state of world fisheries and aquaculture 2016. Contributing to food security and nutrition for all. Rome, p 200Google Scholar
- Gundersen H J G (1977) Notes on the estimation of the numerical density of arbitrary profiles: the edge effect. J Microsc 111:219–223Google Scholar
- Gutierrez J, Rodriguez G, Barry-Ryan C, Bourke P (2008) Efficacy of plant essential oils against foodborne pathogens and spoilage bacteria associated with ready-to-eat vegetables: antimicrobial and sensory screening. J Food Prot 71:1846–1854. https://doi.org/10.4315/0362-028X-71.9.1846 CrossRefGoogle Scholar
- Han GQ, Xiang ZT, Yu B, Chen DW, Qi HW, Mao XB, Chen H, Mao Q, Huang ZQ (2012) Effects of different starch sources on Bacillus spp. in intestinal tract and expression of intestinal development related genes of weanling piglets. Mol Biol Rep 39:1869–1876. https://doi.org/10.1007/s11033-011-0932-x CrossRefGoogle Scholar
- Hernández A, García BG, Caballero MJ, Hernández MD (2016) The inclusion of thyme essential oil in the feed of gilthead seabream (Sparus aurata) promotes changes in the frequency of lymphocyte aggregates in gut-associated lymphoid tissue. Aquac Res 47:3341–3345. https://doi.org/10.1111/are.12758 CrossRefGoogle Scholar
- Navarrete P, Toledo I, Mardones P, Opazo R, Espejo R, Romero J (2010) Effect of Thymus vulgaris essential oil on intestinal bacterial microbiota of rainbow trout, Oncorhynchus mykiss (Walbaum) and bacterial isolates. Aquac Res 41:667–678. https://doi.org/10.1111/j.1365-2109.2010.02590.x Google Scholar
- Osorio A, Silva TM, Duarte LP, Ferraz VP, Pereira MT, Mercadante-Simões MO, Evangelista FCG, Sabino AP, Alcântara AF (2015) Essential oil from flowers of Solanum stipulaceum: composition, effects of γ-radiation, and antileukemic activity. J Braz Chem Soc 26:2233–2240. https://doi.org/10.5935/0103-5053.20150209. Google Scholar
- Pfaffl MW (2004) Quantification strategies in real-time PCR. In: Bustin SA (ed) A-Z of quantitative PCR. International University Line, California, pp 87–112Google Scholar
- Ren P, Xu L, Yang Y, He S, Liu W, Ringø E, Zhou Z (2013) Lactobacillus planarum subsp. plantarum JCM 1149 vs. Aeromonas hydrophila NJ-1 in the anterior intestine and posterior intestine of hybrid tilapia Oreochromis niloticus♀× Oreochromis aureus♂: an ex vivo study. Fish Shellfish Immunol 35:146–153. https://doi.org/10.1016/j.fsi.2013.04.023 CrossRefGoogle Scholar
- Saleh N, Allam T, El-latif AA, Ghazy E (2014) The effects of dietary supplementation of different levels of thyme (Thymus vulgaris) and ginger (Zingiber officinale) essential oils on performance, hematological, biochemical and immunological parameters of broiler chickens. Glob Vet 12:736–744. https://doi.org/10.5829/idosi.gv.2014.12.06.83189 Google Scholar
- Sönmez AY, Bilen S, Alak G, Hisar O, Yanık T, Biswas G (2015) Growth performance and antioxidant enzyme activities in rainbow trout (Oncorhynchus mykiss) juveniles fed diets supplemented with sage, mint and thyme oils. Fish Physiol Biochem 41:165–175. https://doi.org/10.1007/s10695-014-0014-9 CrossRefGoogle Scholar
- Valladão GMR, Gallani SU, Pala G, Jesus RB, Kotzent S, Costa JC, Silva TFA, Pilarski F (2017) Practical diets with essential oils of plants activate the complement system and alter the intestinal morphology of Nile tilapia. Aquac Res 48:5640–5649. https://doi.org/10.1111/are.13386 CrossRefGoogle Scholar
- Zadmajid V, Mohammadi CH (2017) Dietary thyme essential oil (Thymus vulgaris) changes serum stress markers, enzyme activity, and hematological parameters in gibel carp (Carassius auratus gibelio) exposed to silver nanoparticles. Iran J Fish Sci 16:1063–1084Google Scholar