Evaluation of oregano (Origanum vulgare) essential oil supplementation on growth performance, digestive enzymes, intestinal histomorphology and gut microbiota of Black Sea salmon, Salmo labrax

Abstract

This study aimed to determine the effect of dietary oregano (Origanum vulgare) essential oil (EO) on the growth performance, digestive enzyme activity, intestinal histomorphology, and intestinal microbiota of the Black Sea salmon juvenile (Salmo labrax). Fish fed with diets have at different levels oregano EO such as 50, 100, 200, and 400 mg kg−1. For this purpose, a total of 675 fish were distributed randomly in triplicate into 5 experiment groups in 15 experiment tanks. Fish with average initial weights of 3.52±0.01g were fed by hand 3% level of live weight for 90 days. At the end of the study, feeding with oregano EO supplementation didn’t significantly affected the growth performance of fish. Except for pepsin, there were no significant differences in the activity of digestive enzymes among the control and oregano EO groups. Besides, oregano EO at the doses of 50 or 400 mg kg−1 may have the potential to increase the surface area required for digestion by increasing intestinal villi length. Moreover, all doses of oregano EO showed antimicrobial properties by decreasing the count of lactic acid bacteria in the intestine. Supplementation with 100 and 200 mg kg−1 oregano EO in diets decreased the total coliform, Escherichia coli and lactic acid bacteria counts when compared to the control group. The results showed that oregano EO may affect positively digestion and absorption without adverse effects on the growth performance of Black Sea salmon juvenile.

Effect of dietary oregano oil on growth performance, disease resistance, intestinal morphology, immunity, and microbiota of hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂)

“…In this study, OO supplementation did not affect the growth performance of fish. The current study is consistent with a previous study that showed that feeding with OO supplementation also did not significantly affect the growth performance of Black Sea salmon, Salmo labrax (Ozel et al, 2022). However, some research (Magouz et al, 2022) reported that 0.5 and 1 g OO/kg diet could not only relieve the impacts of heat stress but also markedly enhance the final weight, weight gain, and SGR of Nile tilapia.…”

Tarragon (Artemisia dracunculus) Essential Oil at Optimized Dietary Levels Prompted Growth, Immunity, and Resistance to Enteric Red-Mouth Disease in the Rainbow Trout (Oncorhynchus mykiss)

“…The improving effects of TGO may be due to the increases in the amylase, protease, and lipase activities, as their levels were higher in TGO groups [69]. Although there were many studies regarding the inducing impacts of essential oils on digestive enzyme activity in fish [70][71][72][73], we found no literature with TGO. Generally, it seems that essential oils induce digestive enzymes by affecting the pancreas, where they are produced.…”

Oregano Leaf Extract Dietary Administration Modulates Performance, Redox Status, Intestinal Health, and Expression of Some Related Genes of Nile Tilapia (Oreochromis niloticus L.)

“…Particularly, medicinal herbs and their extracts are commonly employed in farmed fish as effective feed additives (Naiel et al, 2019;Sönmez et al, 2021;Amoush et al, 2022;Sönmez et al, 2022 b;Abdel-Latif et al, 2023). In particular, Origanum vulgare L., as a leaf powder or essential oil, is well known for its potency as a therapeutic medication in aquaculture (Khafaga et al, 2020;Özel et al, 2022). Origanum vulgare L. leaf extracts (OVLE) with a high amount of carvacrol are being investigated for their potential application in nutrition as well as their influence on the performance and immunity of fish such as zebrafish (Rashidian et al, 2021) and rainbow trout (Haghighi et al, 2018).…”