Cymbopogon flexuosus essential oil as an additive improves growth, biochemical and physiological responses and survival against Aeromonas hydrophila infection in Nile tilapia

Abstract

The objective of the present study was to evaluate growth, biochemical, hematological and intestinal enzymes responses and survival of Nile tilapia juveniles fed a diet containing the essential oil of lemongrass Cymbopogum fl exuosus (EOCF) and infected by Aeromonas hydrophila. Five diets were evaluated (in quadruplicate) with increasing levels of EOCF (0.0 -control; 0.25; 0.50; 1.0 and 2.0 mL kg diet-1). On day 45, eight fi sh per treatment were sampled and blood, liver and intestine samples were taken. Others eight fi sh per treatment were infected with A. hydrophila followed by a 15day period of observation. Citral is the main constituent of EOCF. The inclusion of 2.0 mL EOCF kg diet-1 increased specifi c growth rate and survival after A. hydrophila infection and decreased feed conversion ratio of Nile tilapia. In general, higher concentrations of EOCF in the diet reduced plasma glucose and triglycerides levels, and increased plasma amino acids, alanine aminotransferase (ALT) and hepatic ALT levels, hematological parameters, and the activity of intestinal enzymes. It was concluded that the inclusion of 2.0 mL EOCF kg diet-1 improved growth performance, biochemical and physiological responses and decreased mortality of Nile tilapia after A. hydrophila infection.

Antibacterial and antibiofilm activities and synergism with florfenicol from the essential oils of Lippia sidoides and Cymbopogon citratus against Aeromonas hydrophila

“…Citral has considerable antibacterial activity against Gram‐negative and Gram‐positive bacteria (Lee et al, 2012; De Souza et al, 2020). Its main mode of action is related to its interaction with lipids to the cell membrane, causing leakage of potassium and cell constituents that can lead to cell death (Scariot et al, 2021).…”

“…Aeromonas hydrophila is one of the main bacteria involved in farmed fish diseases (Dawood et al, 2021; Majolo et al, 2017; Souza et al, 2020). It is a Gram‐negative bacterium, opportunistic in organisms produced in aquaculture, with a high capacity to produce biofilms and large micro colonies, which can be found in different types of aquaculture systems (Li et al, 2019; Lynch et al, 2002).…”

“…An increase in stress in aquatic animals is characteristic of super intensive systems due to reduced space and increased levels of nitrogen compounds (Lemos et al, 2018); these stresses can cause the suppression of the immune system and increase the susceptibility to infectious diseases caused by opportunistic bacteria such as those belonging to the genus Aeromonas (De Souza et al, 2017; Harikrishnan et al, 2010). This can cause an outbreak of infectious diseases in the aquaculture environment and, consequently, death of the cultivated species (Dawood et al, 2021; Souza et al, 2020). Synthetic chemical compounds (antimicrobial) have been widely used in the treatment of diseases in aquaculture.…”

“…According to De Souza et al (2017), essential oils (EOs) are secondary metabolites with enormous pharmacological potential, which can be a promising therapeutic alternative both for the synergistic action with antimicrobials and to inhibit the formation of biofilms. They have the potential to be used in the synthesis of new drugs, since EOs have a great diversity of volatile compounds that perform various biological activities with beneficial effects on animals (Dawood et al, 2021; Souza et al, 2020). The benefits of EOs already reported in aquaculture organisms include antimicrobial, antifungal, antiparasitic, antioxidant, anaesthetic, sedative, immunomodulatory and growth‐promoting activity (Bakkali et al, 2008; Burt, 2004; Da Cunha et al, 2018; De Souza et al, 2019; Teixeira et al, 2018).…”

Macrobrachium rosenbergii fed with essential oil from Lippia alba in the diet in low and high stocking density

“…Essential oils can be used as nutritional additives in fish and crustaceans, showing promising results for welfare and growth (Cagol et al, 2020;De Souza et al, 2020;Souza et al, 2020) and represent a viable alternative to synthetic antibiotics (Felix e Silva et al, 2022).…”