Chitosan Polymeric Nanoparticles as a Carrier of <i>Thymbra spicata</i> Hydroalcoholic Extract: Effect on Growth Parameters in Rainbow Trout (<i>Oncorhynchus mykiss</i>)

Abstract

This study aimed to investigate the effect of using chitosan polymeric nanoparticles (CNPs) on improving the efficiency of hydroalcoholic extract of Thymbra spicata (TS) on the growth parameters of rainbow trout (Oncorhynchus mykiss) fed with the experimental diets containing different levels of TS extract with and without CNPs. Thymbra spicata loaded chitosan polymeric nanoparticles (TSCNPs) were prepared by ionic gelation methods in the presence of sodium tripolyphosphate (TPP). The fourier transform infrared spectroscopy (FT-IR) of TSCNPs showed that the strong peaks due to hydroxyl groups (OH) and alcohol and amine (NH) were shifted to 3427 cm−1, and peak wide has expanded due to increased hydrogen bonds. The FT-IR results were proved the interaction of CNPs and TS extract. The scanning electron microscope (SEM) imaging showed a spherical shape, smooth and homogeneous structure for nanoparticles. In zetasizer results, nanoparticles size average, poly dispersity index (PDI), zeta potential (ZP), and zeta average (d.nm) were 86.1 nm, 0.21, 31.3 mV, and 83.3, respectively. In energy dispersive spectroscopy (EDS) results, the major compounds of TSCNPs included C, O, Al, Cl, Mg, K, and Ca. At the UV-Visible spectrum, the absorption of TS extract based on the absorption of flavonoids was observed at 430 nm. Obtained results showed that the encapsulation efficiency (EE) of the nanoparticles was 94.1%. In vitro, a gradual and acidic dependent period of 120 h was observed in TS release conditions. After eight weeks of feeding, the addition of 400 mg kg-1 diet of TSCNPs resulted in significant improvement in the final weight, final length, specific growth rate (SGR), and survival (S) (P < 0.05). This research suggests that loading Thymbra spicata hydroalcoholic extracts on chitosan polymeric nanoparticles increased the efficiency of plant extract compared to extract pure form and improved the growth performance in rainbow trout.