Effect of lemon balm (Melissa officinalis) extract on growth performance, digestive and antioxidant enzyme activities, and immune responses in rainbow trout (Oncorhynchus mykiss)

Effect of Melissa officinalis L. leaf extract on manganese-induced cyto-genotoxicity on Allium cepa L

Although the antioxidant properties of Melissa officinalis extract (Mox) are widely known, little work has focused on its protective capacity against heavy metal stress. The primary objective of this study was to determine the potential of Mox to mitigate manganese (II) chloride (MnCI2)-induced cyto-genotoxicity using the Allium and comet assays. Physiological, genotoxic, biochemical and anatomical parameters as well as the phenolic composition of Mox were examined in Allium cepa (L.). Application of 1000 µM MnCl2 reduced the rooting percentage, root elongation, weight gain, mitotic index and levels of chlorophyll a and chlorophyll b pigments compared to the control group. However, it increased micronuclei formation, chromosomal abnormality frequencies, tail DNA percentage, proline amount, lipid peroxidation level and meristematic damage severity. The activities of superoxide dismutase and catalase also increased. Chromosomal aberrations induced by MnCl2 were fragment, sticky chromosome, vagrant chromosome, unequal distribution of chromatin and bridge. Application of 250 mg/L Mox and 500 mg/L Mox along with MnCl2 significantly alleviated adverse effects dose dependently. The antioxidant activity bestowed by the phenolic compounds in Mox assisted the organism to combat MnCl2 toxicity. Consequently, Mox exerted remarkable protection against MnCl2 toxicity and it needs to be investigated further as a potential therapeutic option.

Dietary flaxseed (Linum usitatissimum) oil supplementation affects growth, oxidative stress, immune response, and diseases resistance in rainbow trout (Oncorhynchusmykiss)

This paper describes the effects of flaxseed (Linum usitatissimum) oil (FSO) as a feed additive on growth performance, oxidative stress, immunity, and disease resistance in rainbow trout (Oncorhynchus mykiss). Four-hundred-and-twenty rainbow trout individuals (mean weight: 25.66 ± 1.33 g) were fed with different doses of FSO (0.5, 1, and 1.5%) ad libitum two times a day for 9 weeks. At the end of the feeding, growth performance was evaluated and the fish were challenged with two different bacteria (Yersinia ruckeri and Aeromonas hydrophila). At the end of the 3rd, 6th, and 9th weeks, blood and tissue samples were collected from 9 fish per treatment to evaluate innate immune response, cytokine gene expression levels, antioxidant enzyme activities and lipid peroxidation levels, and digestive enzyme activities. Determination of haematological parameters and histological examination was also carried out to evaluate the general health status of the fish. Results showed that the final weight and specific growth rate of fish supplemented with FSO increased significantly (p < 0.05). FSO-supplemented fish showed higher resistance to Y. ruckeri infection than the control group (p < 0.05). However, survival rates of all groups in A. hydrophila challenge test were similar (p > 0.05). Among the investigated innate immune response parameters, the potential killing activity of phagocytes, myeloperoxidase activity, and lysozyme activity increased in the FSO-supplemented groups (p < 0.05). Almost all cytokine gene expression levels in the experimental groups up-regulated especially after 9 weeks of feeding in the head kidney and intestine (p < 0.05). Similarly, superoxide dismutase and catalase activities were found to be significantly higher in the FSO group than in the control (p < 0.05) whereas, the lipid peroxidation levels drastically declined as a result of the FSO supplementation (p < 0.05). These results suggest that FSO can improve growth, enhance immune response, and lower oxidative damage in rainbow trout when supplemented at the rates of 0.5-1.5% for 9 weeks.

Growth Performance, Immune Response, Antioxidative Status, and Antiparasitic and Antibacterial Capacity of the Nile Tilapia (Oreochromis niloticus) After Dietary Supplementation With Bottle Gourd (Lagenaria siceraria, Molina) Seed Powder

Medicinal plants are a potential safe source of bioactive compounds. Fish diet supplemented with the medicinal plant bottle gourd (Lagenaria siceraria) seed powder was evaluated in this study for the potential effect on growth performance, antioxidative status, immunological response, and resistance to infectious pathogens in the Nile tilapia (Oreochromis niloticus). Nile tilapia fingerlings with mean weight ( ± SD)= (25.64 ± 0.17 g), were fed four L. siceraria seed supplemented diets (LSSD) at 0.0, 1, 2, and 3% for 60 days. Specimens were then challenged with the bacterium Aeromonas hydrophila for 10 days. Also, three different concentrations (2.5, 5, and 10 ml/L) of Lagenaria siceraria ethanolic extract (LSEE) were tested for their antibacterial and antiparasitic efficacy on four selected bacterial and one parasitic species. All parameters’ values generally improved with elevating the content of the L. siceraria seed powder in the diet. Dietary administration of LSSD-3% enabled significant (P &lt; 0.05) higher growth performance, and feed utilization efficiency. It reduced the mortality induced by A. hydrophila infection, increased crude protein content in the fish body and exhibited the highest in vitro antibacterial and antiparasitic efficiency. RBCs, WBCs, Hb, PCV, MCV, MCH, and total serum protein values in pre- and post-challenge groups were significantly higher (P &lt; 0.05) in the LSSD-3% group. While MCHC, ALT, AST and glucose levels were significantly lower (P &lt; 0.05) than those of the other groups. Lysozyme and antioxidant enzyme activities in pre- and post-challenge groups were also higher (P &lt; 0.05) in the LSSD-3% group compared to the other groups. LSEE provided good efficacy against Gram-negative bacterial strains, mild efficacy against Gram-positive bacterial strains, and an antagonistic effect on the parasite Cichlidogyrus Tilapiae. The 10 ml/L concentration was the most effective against the pathogens followed by the 5 ml/L concentration and then 2.5 ml/L. Our findings suggest the feasibility of supplementation of Nile tilapia (O. niloticus) diet with L. siceraria seed powder by 3% to improve the growth performance, immunity, and vital parameters.

The Impact of LED Lighting Spectra in a Plant Factory on the Growth, Physiological Traits and Essential Oil Content of Lemon Balm (Melissa officinalis)

With the recent development of LED lighting systems for plant cultivation, the use of vertical farming under controlled conditions is attracting increased attention. This study investigated the impact of a number of LED light spectra (red, blue, green and white) on the growth, development and essential oil content of lemon balm (Melissa officinalis), a herb and pharmaceutical plant species used across the world. White light and red-rich light spectra gave the best outputs in terms of impact on the growth and yield. For blue-rich spectra, the development and yield was lower despite having a significant impact on the photosynthesis activity, including Fv/Fm and NDVI values. For the blue-rich spectra, a peak wavelength of 450 mn was better than that of 435 nm. The results have practical value in terms of increased yield and the reduction of electricity consumption under controlled environmental conditions for the commercial production of lemon balm.

Egg enrichment with n-3 fatty acids in farmed hens in sub-optimum temperature: A cold-temperament additive mix alleviates adverse effects of stress on performance and health

At some stage, laying hen farming is likely to be subjected to sub-optimum temperatures (SOTem) due to climate change. While egg enrichment with n-3 fatty acids is a common practice in the poultry industry, in SOTem it has been less investigated. This study tested the effects of egg enrichment through extruded flaxseed (FLX) (180 g/kg) alone or along with hulled-soaked barley (H-SB) (170 g/kg), namely FLBA, with and without a cold-temperament additive mix (CTA) (25 g/kg: 5 g/kg flixweed (Descurainia sophia), 10 g/kg dried herb-extraction residues from pussy willow (Salix aegyptiaca) and 10 g/kg dried lemon (Citrus limon) residue) in two temperatures (20°C and SOTem: 27°C) on egg performance, yolk fatty acids, lipid components, blood biochemistry, serological enzymes, antioxidant and immune system of Hy-Line W-36 53-week-old for 9 weeks. Two hundred seventy layers were randomly distributed to nine treatments, resulting in six replicates with five hens. Hens fed flaxseed diets, regardless of temperature or CTA, had higher levels of n-3 fatty acids in yolks than others. Temperature negatively influenced feed intake and egg production. FLX + H27 and FLBA + H27 groups outperformed the other groups regarding cholesterol in yolk (10.1, 10.3 mg/g yolk), high-density lipoprotein (HDL) (5.19, 4.93 mg/g yolk), total protein (FLX + H27: 6.82 mg/dl), HDL in the blood (FLBA + H27:83.8 mg/dl), superoxide dismutase (FLBA + H27:90.4 U/ml), glutathione reductase (FLBA + H27: 1042.1 U/ml), glutathione peroxidase (FLX + H27: 1149.7 U/ml) and catalase (FLBA + H27: 12.5 U/ml). Total antibody, immunoglobulin G and immunoglobulin M after 42 days were significantly higher in chicks fed CTA-added diets (p < 0.05). Replacing corn and soya bean meal with H-SB did not negatively change the above-mentioned factors. Our findings collectively suggest that egg enrichment with n-3 fatty acids through dietary FLBA + H27 (180 g/kg flaxseed, 170 g/kg H-SB, and 25 g/kg CTA) in SOtem is suggested without any adverse impacts.

Methodologies to Assess the Bioactivity of an Herbal Extract on Immunity, Health, Welfare and Production Performance in the Chicken: The Case of Melissa officinalis L. Extract

The potential of herbal extracts containing bioactive compounds to strengthen immunity could contribute to reducing antimicrobial use in poultry. This study aimed at developing a reliable and robust methodological pipeline to assess the ability of herbal extracts to strengthen chicken innate defenses, especially concerning inflammation and oxidative stress. This methodology was applied to Melissa officinalis L. (MEL) extract, recognized for its biological activities including antioxidant and anti-inflammatory properties. Different methods were used to (1). guarantee the quality of MEL extract and its capacity to stimulate the innate immune system; (2). evaluate the relevance of an ex vivo model to mimic inflammatory and oxidative stress challenges to replace LPS injection in chickens; (3). analyse the effects of feed supplemented with MEL extract on inflammation and oxidative stress induced ex vivo; (4). assess the effects of MEL extract on the redox balance, health, welfare and performance in broilers exposed to suboptimal starting conditions through a large-scale approach. The quality of MEL extract preparations, through phytochemical quantification of rosmarinic acid (RA), revealed varying concentrations of RA in the different MEL extracts. RA concentrations remained stable for at least 9 months and in feed three months after incorporating MEL extract. When incubated with chicken cell lines MEL extract showed potential metabolic activation and ability to stimulate immune functions but induced cytotoxicity at high concentrations. The original ex vivo model of inflammation developed on chicken blood cells enabled inflammation and oxidative stress biomarkers to be expressed and revealed antioxidative and anti-inflammatory properties of blood cells from chickens fed MEL extract. The experimental model of chicken suboptimal starting conditions validated beneficial effects of MEL extract on the redox balance and also evidenced improved performance during the growth phase, a tendency for fewer muscle defects but a higher severity of pododermatitis lesions without affecting other welfare indicators. This study grouped methods and tools that could be combined according to the plant extract, the needs of professionals working in poultry production systems and staff responsible for animal health, welfare and feeding.

Modulatory effects of laurel-leaf cistus (Cistus laurifolius) ethanolic extract on innate immune responses and disease resistance in common carp (Cyprinus carpio)

Medicinal herbs are used for growth promotion, disease control and other health benefits in aquaculture industry. Here, we examined the effect of dietary laurel-leaf cistus (Cistus laurifolius) ethanolic extract on growth performance, digestive enzyme activity, haematological profile and nonspecific immune responses in common carp (Cyprinus carpio). In addition, resistance against Aeromonas hydrophila infection was examined. Common carp was fed diets containing 0 (Control), 0.1 (CL0.1), 0.5 (CL0.5) and 1 (CL1) g kg^-1 laurel-leaf cistus extract for 45 days. After 30 days, superoxide anion production (SAP) increased in CL0.1 and CL0.5 fish groups and at the end of the study all experimental fish groups had higher SAP compared to that of the control (P ˂ 0.05). Lysozyme activity (LA) was elevated in CL0.5 and CL1 treated groups on 30th day (P < 0.05), and this increase was only observed in C0.1 fish group at the end of study compared to control (P ˂ 0.05). Myeloperoxidase activity was significantly increased in CL0.5 and CL1 fish groups at the end of study. IL-1βgene expression was significantly increased in treated fish in a dose-depended manner. Similar results were observed for transcription of IL-6 and IL-8 (P < 0.05). Anti-inflammatory cytokines, IL-10 and TGF-β were highly up-regulated in the intestine and head kidney of CL treated fish groups compared to control (P < 0.05). At the end of experiment, significantly higher final body weight, weight gain, and specific growth rate were obtained in CL0.1 treated fish group compared to control. However, growth was negatively affected in CL1 fish group (P < 0.05). CL1 fish group had also a significantly higher FCR. Amylase activity was significantly increased in all experimental fish groups compared to control (P ˂ 0.05). Trypsin activity was decreased in CL0.1 and CL1 fish groups (P ˂ 0.05). WBC and RBC were significantly increased (P ˂ 0.05) in CL0.5 and CL1 fish groups, whereas haemoglobin, haematocrit, mean cell, mean cell haemoglobin contents were no significantly changed among control and treatment groups. Result of challenge test with A. hydrophila exhibited that survival rate in all treatment groups was significantly higher than that of control. These findings demonstrated that laurel-leaf cistus at 0.1 g kg^-1 can be a suitable candidate for growth promotion, immune system induction and infection control in fish.

Antioxidant enzyme activities and immune responses in rainbow trout (Onchorhynchus mykiss) juveniles fed diets supplemented with dandelion (Taraxacum officinalis) and lichen (Usnea barbata) extracts

In the present study, antioxidant activity, immune responses, and growth performance of rainbow trout (Onchorhynchus mykiss) juveniles fed with diets supplemented with dandelion (Taraxacum officinalis) and lichen (Usnea barbata) extracts were assessed. Four different concentrations of aqueous methanolic extract of the plants (0% (control), 0.1%, 0.5%, and 1% (D, dandelion; L, lichen) were added to the diets, and fish were fed for 75 days. On the 15^th, 45^th, and 75^th day of the study, liver antioxidant enzyme activities were determined, and immune responses were determined every 15^th day. The results showed that SOD activity increased in the fish group of 0.1% D on the 15^th and 45^th day compared to control; however, it was lower in all the lichen extract-treated groups than in control at almost all sampling times, except on the 15^th day in the 0.1% L group. CAT activity showed an increased value (P < 0.05) in 0.5% L and 1% L treated fish groups on the 15^th day, in fish of 1% D and 1% L groups on 45^th and on 75^th day in 0.1% D group. GPX activity increased on the 15^th day of the study in fish of 0.1% D group, on the 45^th day in 1% D and 1% L groups and on the 75^th day in fish of 0.5% D, 0.1% D, and 0.5% L groups (P < 0.05). G6PDH enhanced in all treatment groups compared to control on the 15^th day, except in 0.1% L and 0.5% L groups. An elevated G6PDH activity was also observed on the 75^th day of the study in 0.5% D, 1% D, and 0.5% L fish groups. An increase on lipid peroxidation (LP) was observed in all L groups on the 45^th day of the study. Lysozyme activity was determined to be the highest in 0.5% and 1% L on the 45^th day, in 0.1% L on the 60^th day and in the 0.5% L fish group on the 75^th day compared to control (P < 0.05). Myeloperoxidase was found to be the highest at the end of the study in 1% L fish group compared to the control (P < 0.05). In conclusion, we suggest the use of dandelion to combat oxidative stress and to lower FCR and the use of lichen to modulate the immune response in rainbow trout. The use of such products will be economical for aquaculture and harmless for the environment.

Effects of Greek juniper (Juniperus excelsa) extract on immune responses and disease resistance against Yersinia ruckeri in rainbow trout (Oncorhynchus mykiss)

This study investigated the effects of Greek juniper extract on immune responses of rainbow trout. In this experiment, 4 doses [0 (Control), 1 (J1), 4 (J4) and 8 (J8) mg/kg] of the extract were administered orally using an oral gavage twice a day for 14 days. Immune responses were measured on 7th and 14th days. On 14th day, Yersinia ruckeri was injected intraperitoneally to all fish of all groups. On 14th day, ORP in fish of J1 group increased significantly. Lysozyme activity (LA) was increased in J8 group on 7th day (p < .05). On 14th day, a significant decrease was determined in J1 and J4 treatments in LA. Myeloperoxidase activity was significantly decreased in all groups irrespective of sampling times (p < .05). Interleukin (IL)-1β was significantly elevated in fish of J8 group on 7th day. IL-8 increased in fish of J8 and J4 groups on 7th day of the study. IL-12 gene expression was significantly up-regulated in J8 fish group on 7th day, and in J4 fish group on 14th day. Survival rate was higher in J8 treatment compared to the control and other treatments (p < .05). The results suggest that Juniperus excelsa provides protection against Y. ruckeri in rainbow trout.

A novel herbal immunostimulant for rainbow trout (Oncorhynchus mykiss) against Yersinia ruckeri

In this 21-day study, we examined the effects of the aqueous methanolic extract of thin-skinned plum (Prunus domestica) on growth, immune response and resistance to a pathogenic bacterium, Yersinia ruckeri in rainbow trout (Oncorhynchus mykiss). Fish were fed with diets containing thin-skinned plum extract doses as 0 (Control) 0.1 (PD01), 0.5 (PD05) and 1% (PD1) ad libitum twice in a day. At the end of the study, growth was affected positively but not significantly. Feed conversion ratio (FCR) was decreased in the PD01 group (P < 0.05). There were elevated respiratory burst and potential bacterial killing activities on the 7th day in the PD1 fish group. No differences were observed in lysozyme activity (P > 0.05). An increased myeloperoxidase activity was recorded on the 14th day of study. Expression of interleukin and COX-2 genes was elevated on the 7th day of study in the kidney and intestine of treated fish. Histological results indicated no marked changes in organs (gill, kidney, liver and spleen) of PD treated fish groups. Challenge results of fish in all plum extract-treated groups showed an increased survival rate against Y. ruckeri (P < 0.05). This study indicated that the thin-skinned plum aqueous methanolic extract could improve innate immunity, survival against Y. ruckeri and decrease the FCR level.

Effects of ribwort plantain (Plantago lanceolata) extract on blood parameters, immune response, antioxidant enzyme activities, and growth performance in rainbow trout (Oncorhynchus mykiss)

In this study, we examined changes occurred in blood parameters, immune responses, antioxidant enzyme activities, and growth performance of rainbow trout (Oncorhynchus mykiss) administered with ribwort plantain (RP) through feed. Fish (mean weight 36.56 ± 1.99 g) were fed a diet supplemented with an aqueous methanolic extract of RP at variable doses, 0 (control), 1 (RP1), 2 (RP2), and 3 g kg^-1 (RP3) for 90 days. The final weight, weight gain, and specific growth rate were significantly increased in RP1, RP2, and RP3 treatment groups compared to that of the control. Among examined blood parameters, hemoglobin value in RP1 group (9.77 ± 0.10 g dl^-1) only was significantly high on the 30th day of the study. When immune response parameters were evaluated, we observed that oxidative radical production and lysozyme activities were affected positively in experimental groups (P < 0.05). The highest oxidative radical production was determined in fish of RP3 group. Glutathione peroxidase and glucose 6 phosphate dehydrogenase were increased in RP3 group compared to control and other treatment groups. Based on these results, it is concluded that ribwort plantain promotes growth, enhances immune responses and antioxidant enzyme activities in rainbow trout, and therefore, may be used in aquaculture.