Encapsulation of essential oils of rosemary (

Abstract

Context Dietary supplementation with phytobiotics may form part of an alternative strategy to the use of antibiotics as growth promoters in the poultry industry. Essential oils of rosemary (Rosmarinus officinalis L.) may have antimicrobial and antioxidant properties. Aims The aims were to evaluate in vitro characteristics of non-encapsulated and encapsulated rosemary essential oils, and to investigate their effects on growth performance, intestinal morphology and microbial population in broiler chickens. Methods Essential oil main components were determined, and the minimum inhibitory concentration and 2,2-diphenyl-1-picrylhydrazyl radical assay methods were applied for determination of antimicrobial and antioxidant activities, respectively. In an in vivo study of performance, 1-day-old male chicks (n = 420) were randomly assigned to seven dietary treatments with five replicates of 12 birds in a completely randomised experimental design. Treatments were control (basal) diet, and basal diet supplemented with chitosan (encapsulating agent) at 150 mg/kg, encapsulated and non-encapsulated rosemary essential oils at both 150 and 300 mg/kg, and the antibiotic flavophospholipol at 650 mg/kg. Key results Non-encapsulated essential oil had stronger antioxidant activity than the encapsulated form (IC50 values 0.969 and 1.879 mg/mL, respectively). Non-encapsulated essential oil had greater antimicrobial effect against Escherichia coli, whereas the encapsulated form was more effective against Staphylococcus aureus. During the whole growing period of the in vivo study, supplementation with different levels of non-encapsulated or encapsulated essential oils significantly (P < 0.01) improved bodyweight gain and feed conversation ratio compared with control and antibiotic diets. Furthermore, feed intake in birds receiving essential oils (150 or 300 mg/kg) was lower (P < 0.01) than in other groups. Villus height was increased (P < 0.01) in birds supplemented with essential oils compared with all other treatments. Ileal coliform count was lower in birds supplemented with non-encapsulated essential oil at 150 mg/kg than in birds fed the control diet. Conclusion Use of non-encapsulated rosemary essential oils at 150 mg/kg is recommended. Encapsulation did not provide additional benefits for most parameters. Implications Rosemary essential oils offer a potential replacement to conventional antibiotics in poultry nutrition, reducing the spread of antibiotic-resistant bacteria and presence of antibiotic residues in animal tissues.

Encapsulation as a Way to Improve the Phytogenic Effects of Herbal Additives in Broilers – An Overview

“…In respect to the antioxidant activity, Amiri et al (2021) showed that the chitosannanoencapsulated garlic essential oil had significantly better antioxidant activity than the free form. As reported by Mousapour et al (2020), antioxidant activity also increased with chitosan encapsulation in savory essential oil. Ke et al (2021) comprehensively review the detailed antibacterial properties and the application of chitosan as well as the potential synergistic effect between chitosan and other active compounds.…”

“…In an in vitro (inhibition zone) study, chitosan-nanoencapsulated garlic essential oil was more effective against E. coli than the free form (nonencapsulated) (Amiri et al, 2021). Similar to the abovementioned study, Mousapour et al (2020) found that savory (Satureja hortensis L.) essential oil encapsulated with chitosan exhibited stronger antibacterial action against E. coli than the nonencapsulated form. Note that savory essential oil possesses unique biological properties, such as antibacterial properties, due to the presence of key chemical components, including carvacrol and thymol (Vitanza et al, 2019).…”

“…Moreover, Mousapour et al (2020) reported no substantial effect of encapsulated savory essential oil as compared to the nonencapsulated savory essential oil in terms of growth rate, gut morphology, and bacterial population in broilers. Owing to these facts, some factors may determine the efficacy of encapsulated herbal additives on broilers, including the nature of herbs (types, quality, the concentration of bioactive compounds, etc.…”

“…In contrast, water-soluble polymers provide gentle and simple preparation procedures that do not require the use of an organic solvent or a significant shear force (Meimandipour et al, 2017). Among the water-soluble coating materials that have been used, chitosan has recently received a lot of attention from poultry nutritionists (Mousapour et al, 2020;Amiri et al, 2021). Chitosan is a nontoxic, biodegradable, mucous adhesive and biocompatible amino polysaccharide that may be used to encapsulate a variety of active substances for a variety of uses.…”

“…Meimandipour et al (2017) confirmed that chitosan had better delivery system of herbal extract on the absorption site (intestine) of broilers. Apart from its potential as a coating material, chitosan's antibacterial properties have piqued poultry nutritionists' interest in using it not only as a coating material but also as an antimicrobial agent that is helpful to broiler health (Mousapour et al, 2020;Amiri et al, 2021).…”