Dietary effect of apple cider vinegar and propionic acid on immune related transcriptional responses and growth performance in white shrimp, Litopenaeus vannamei

An Overview of the Biological Functions and Mechanisms of Action of Medicinal Plants and Seaweeds in the Shrimp Culture

Diseases are major constraints to developing large-scale aquaculture practices in many countries. For decades, synthetic chemotherapeutic agents have been widely applied both as prophylactics and therapeutics to inhibit and control aquatic disease outbreaks. However, their use has become more restricted due to the negative impacts they have on the environment, the host and humans, as well as their limitations in preventing the emergence of antimicrobial-resistant bacteria. Therefore, there is a growing interest in the use of medicinal plants and seaweeds as potential alternatives to antibiotics and other synthetic chemotherapeutics. Medicinal plants and seaweeds can enhance the immune systems of animals, thereby providing protection against numerous diseases while minimizing the adverse effects associated with synthetic chemotherapeutics. Furthermore, the advantages of medicinal plants and seaweeds, such as their effectiveness, easy availability and ability to be applied on a large scale, make them appealing for use in the aquaculture industry. The main goal of this study was to review the existing knowledge of the effects of medicinal plants and seaweeds, as well as their extracts, on shrimp growth, immune response and disease resistance against bacterial and viral agents. Moreover, this paper discusses the application of seaweeds in shrimp culture. We also conducted a literature review to identify gaps in the research and provide recommendations for further advancement in this field of study. Further studies should focus on evaluating other physiological aspects, such as feed and mineral utilization, enzyme activities and histological examination.

Effect of paprika extracts on growth performance, haemolymph chemistry, intestinal microbiota and antioxidant enzyme activities of white-leg shrimp (Litopenaeus vannamei)

This study aims to evaluate the effects of paprika extract on the survival rate, growth performance and stimulation of the innate immune system of Litopenaeus vannamei. In this experiment, 240 healthy shrimp (3.22 ± 0.12 g) were randomly divided into four groups. The shrimp were fed diets with different concentrations of paprika oil extracts (0%, 0.5%, 1% and 2%) for 8 weeks. The results showed that growth performance, urea, uric acid, creatinine, cholesterol levels, aspartate aminotransferase and alkaline phosphatase activities were not significantly affected by adding paprika extract to the shrimp diet (p > 0.05). Diets containing 1% and 0.5% paprika extract showed the highest levels of total protein and triglyceride, respectively (p < 0.05). There was a significant decrease in haemolymph glucose concentration in shrimp-fed diets containing 1% and 2% paprika extract (p < 0.05). Moreover, a diet containing 0.5% paprika extract resulted in the highest levels of total heamocyte count, hyaline cells and large-granular cells in shrimp (p < 0.05). Higher catalase and superoxide dismutase activities were also exhibited in the paprika groups (p < 0.05). Vibrio sp. bacteria were not significantly reduced by paprika extract in the intestines of L. vannamei (p > 0.05). A significant decrease in heterotrophic bacteria was observed with increasing extract concentrations (p < 0.05). The shrimp culture industry can utilize paprika extract as a cost-effective, efficient and environmentally friendly immune stimulant at a concentration of 0.5%.

Evaluation of apple (Malus domestica) cider vinegar and garlic (Allium sativum) extract as phytogenic substitutes for growth-promoting dietary antibiotics in sexed broiler chickens

Tightening global regulations on the use of subclinical dietary antibiotics to enhance broiler growth are in response to increasing concern about the risk of resistance and their residues in animal products. The study evaluated the potential of apple cider vinegar (ACV) and garlic extract (GAE) as safer, phytogenic alternatives. A batch of 390 mixed-sex Ross 308-d-old broiler chicks was received into an open, deep litter house, and feather sexed in the second week into 30 experimental units of 13 birds per 2.03 m2 pen. From days 1 to 22, all chicks were on a 200 g/kg crude protein, coccidiostat-treated commercial starter diet. During the grower (16 to 28 days) and finisher (29 to 42 days) phases, chick pens were assigned treatments in a 2 (sex) × 5 (additives) factorial experiment replicated three times. The GAE was a pure extract, while ACV was produced by fermenting 1,000 g fresh apple and 80 g supplementary brown cane sugar in 1.3 liters of water for 4 wk. The five treatments comprised antibiotic (15% granular zinc bacitracin and 12% valinomycin sodium, each at 500 g/tonne) grower (190 g/kg crude protein, 13.0 MJ ME/kg) and finisher (165 g/kg crude protein, 13.2 MJ ME/kg) commercial diets with untreated drinking water as positive controls (PC), antibiotic-free duplicates of the PC diets with untreated drinking water as the negative controls (NC), with 3 mL/L filtered ACV in drinking water (T1), 2 mL/L filtered GAE-treated drinking water (T2), or mixed (3 mL/L ACV + 2mL/L GAE) additive drinking water (T3). Males had higher (P < 0.05) feed intake than females in both growth phases. Birds on the PC gained more (P < 0.05) weight than others. Birds on the PC consumed more feed (P < 0.05) during the finisher phase than T1, T2, and the NC. Birds on the PC had a lower (P < 0.05) grower-phase feed convesion (feed:gain) ratio (FCR) than others, and lower (P < 0.05) FCR during the finisher phase than birds on T1 and T3. Birds on the PC had higher (P < 0.05) percent spleen weight than birds on T1, with smaller proventriculi (P < 0.05) than on NC, T1, T2, and T3, and smaller gizzard weight than birds on the T2 and T3. Birds on the NC exhibited less dressing percentage (P < 0.05) than all other treatments. Meat pH was higher (P < 0.05) in males. In conclusion, in contrast to dietary antibiotics, except for improved dressing percentage, the ACV and GAE did not express phytogenic benefit at the experimental dosage.

The first reporting of prevalence Vibrio species and expression of HSP genes in rayed pearl oyster (Pinctada radiata) under thermal conditions

The main goal of the present study was to evaluate the influence of thermal exposure on Vibrio population and HSP genes expression (HSP 90, HSP70, and HSP20) in rayed pearl oyster (P. radiata). To this end, the oysters were reared for 30 days at temperatures of 22 °C (control), 25 °C, 27 °C, and 29 °C. The results showed that five dominate Vibrio strains including Vibrio hepatarius, V. harveyi, V. alginolyticus, V. parahaemolyticus, and V. rotiferianus were identified. The highest population of V. parahaemolyticus, V. alginolyticus, and V. harveyi, was found in 29οC group. According to real-time PCR, mantle exhibited the highest expression levels of HSP20, HSP70, and HSP90 genes. A higher level of HSP20 expression was observed at high temperatures (25 °C, 27 °C, and 29 °C) in the gonad and mantle compared to the control group (22 °C) while decrease in HSP90 expression level was recorded in 25 °C, 27 °C, and 29 °C groups. HSP20 expression level in adductor muscle was remarkably down-regulated in 27 °C and 29 °C groups. In this tissue, HSP70 was detected at highest levels in the 29οC group. In mantle, HSP90 gene expression was lowest at 22 °C water temperature. Several Vibrio strains have been identified from pearl Gulf oyster that haven't been previously reported. The identification of dominant Vibrio species is essential for epidemiological management strategies to control and prevent Vibrio outbreaks in pearl oyster farms. The expression pattern of HSP genes differs in rayed pearl oyster tissues due to differences in their thermal tolerance capability and physiological and biological characteristics. The present study provides useful molecular information for the ecological adaptation of rayed pearl oysters after exposure to different temperature levels.

Analysis of differentially expressed proteins after EHP-infection and characterization of caspase 3 protein in the whiteleg shrimp (Litopenaeus vannamei)

Whiteleg shrimp (Litopenaeus vannamei) is the most important species of shrimp farmed worldwide in terms of its economic value. Enterocytozoon hepatopenaei (EHP) infects the hepatopancreas, resulting in the hepatopancreatic microsporidiosis (HPM) of the host, which causes slow growth of the shrimp and poses a threat to the farming industry. In this study, differentially expressed proteins (DEPs) between EHP-infected and uninfected shrimp were investigated through proteomics sequencing. A total of 9908 peptides and 2092 proteins were identified. A total of 69 DEPs were identified in the hepatopancreas (HP), of which, 28 were upregulated and 41 were downregulated. Our results showed that the differences among the level of multiple proteins involved in the apoptosis were significant after the EHP infection, which indicated that the apoptosis pathway was activated in whiteleg shrimp. In addition, expression leve of caspase 3 gene were identified related to the EHP infection. Furthermore, predictions of spatial structure, analysis of phylogeny and chromosome-level linearity of the caspase 3 protein were performed as well. In conclusion, a relatively complete proteomic data set of hepatopancreas tissues in whiteleg shrimp were established in this study. Findings about genes involved in the apoptosis here will provide a further understanding of the molecular mechanism of EHP infection in the internal immunity of whiteleg shrimp.

Effects of dietary yeast culture on health status in digestive tract of juvenile Pacific white shrimp Litopenaeus Vannamei

A feeding trial was conducted to investigate the effects of dietary yeast culture (YC) on health status in digestive tract of juvenile Pacific white shrimp Litopenaeus Vannamei. Shrimps (initial weight: 3.33 ± 0.06 g) were fed with graded levels of dietary YC (control, 0.3%, 0.5% and 1.0%). Results of the present study showed that villus height and the ratio between villus height and crypt depth in the digestive tract of juvenile shrimp was significantly increased by dietary 0.5% and 1.0%YC (P < 0.05). Besides, dietary 0.5% and 1.0%YC significantly activities of phenoloxidase (PO), lysozyme (LZ), acid phosphatase (ACP) and alkaline phosphatase (AKP) (P < 0.05), significantly up-regulated mRNA levels of prophenoloxidase (propo), lysozyme (lz), anti-lipopolysaccharide factor (alf), crustin and penaienadin (P < 0.05) and down-regulated mRNA levels of caspase-1, nuclear factor κB p65 (nf-κbp65) myeloid differentiation primary response protein (myd88) and toll like receptor (tlr) in the digestive tract of juvenile shrimp (P < 0.05). Compared with the control, dietary 0.5%YC increased Chao1 index in the digestive tract of juvenile shrimp. In addition, compared with the control, dietary 0.5% and 1.0%YC significantly increased relative abundance of Lactobacillus (P < 0.05). It can be concluded that dietary YC made positive contribution to health status in digestive tract of juvenile shrimp through improving morphology and microbiota, enhancing immune function, and inhibiting inflammation of digestive tract.

Chronic toxicity of shrimp feed added with silver nanoparticles (Argovit-4®) in Litopenaeus vannamei and immune response to white spot syndrome virus infection

In recent years, the application of silver nanoparticles (AgNPs) as antibacterial compounds has been widely used in human and veterinary medicine. In this work, we investigated the effects of AgNPs (Argovit-4®) as feed additives (feed-AgNPs) on shrimp (Litopenaeus vannamei) using three different methods: 1) chronic toxicity after 28 days of feeding, 2) Effects against white spot syndrome virus (WSSV) challenged by oral route, and 3) transcriptional responses of immune-related genes (PAP, ProPO, CTL-3, Crustin, PEN3, and PEN4) following WSSV infection. The results showed that the feed-AgNPs did not interfere with the growth and survival of shrimp. Also, mild lesions in the hepatopancreas were recorded, proportional to the frequency of the feed-AgNP supply. Challenge test versus WSSV showed that feeding every 7 days with feed-AgNPs reduced mortality, reaching a survival rate of 53%, compared to the survival rates observed in groups fed every 4 days, daily and control groups of feed-AgNPs for the 30%, 10%, and 7% groups, respectively. Feed-AgNPs negatively regulated the expression of PAP, ProPO, and Crustin genes after 28 days of treatment and altered the transcriptional responses of PAP, ProPO, CTL-3, and Crustin after WSSV exposure. The results showed that weekly feeding-AgNPs could partially prevent WSSV infection in shrimp culture. However, whether or not transcriptional responses against pathogens are advantageous remains to be elucidated.

Effect of garlic (Allium sativum) extract on growth, enzymological and biochemical responses and immune-related gene expressions in giant freshwater prawn (Macrobrachium rosenbergii)

In the current study, growth performance, biochemical constituents of muscle, activities of enzymes in the haemolymph, and expressions of immune-related genes were evaluated in the giant freshwater prawns Macrobrachium rosenbergii fed diets supplemented with aqueous garlic (Allium sativum) extract at 0, 5, 10 and 20 g/kg (w/w) for 60 days. At the end of the feeding trial, weight gain and specific growth rate were significantly improved in garlic-fed prawn groups compared with the control (p < 0.05). Moreover, feed conversion ratio was significantly lower in the garlic-fed groups than in the control (p < 0.05). Activities of catalase, superoxide dismutase and glutathione peroxidase in the hepatopancreas, activities of alanine aminotransferase, aspartate aminotransferase and levels of albumin and total protein in the hemolymph were significantly increased in the garlic treatments (p < 0.05). Furthermore, garlic supplemented diets improved muscle biochemical profiles, particularly contents of crude protein and total ash and upregulations of immune deficiency and heat shock proteins (HSP70) gene expression (p < 0.05). Therefore, garlic has positive effects on growth performance and physio-biochemical responses of M. rosenbergii, and thus, it can be used as an additive for stress resistance and as a growth promoter in sustainable aquaculture.

Agavin induces beneficial microbes in the shrimp microbiota under farming conditions

Prebiotics and probiotics have shown a number of beneficial impacts preventing diseases in cultured shrimps. Complex soluble carbohydrates are considered ideal for fostering microbiota biodiversity by fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPS). Here we evaluated the growth performance and microbiota composition of the white shrimp Litopenaeus vannamei after dietary intervention using agavin as a FODMAP prebiotic under farming conditions. Adult L. vannamei were raised at a shrimp farm and the effect of agavin supplemented at 2% (AG2) or 10% (AG10) levels were compared to an agavin-free basal diet (BD). After 28 days-trial, the feed conversion ratio, total feed ingested, and protein efficiency ratio was significantly improved on animals fed with AG2. At the same time, no effect on growth performance was observed in AG10. Surprisingly, after sequencing the V3-V4 regions of the 16S rRNA gene a higher microbial richness and diversity in the hepatopancreas and intestine was found only in those animals receiving the AG10 diet, while those receiving the AG2 diet had a decreased richness and diversity, both diets compared to the BD. The beta diversity analysis showed a clear significant microbiota clustering by agavin diets only in the hepatopancreas, suggesting that agavin supplementation had a more substantial deterministic effect on the microbiota of hepatopancreas than on the intestine. We analyzed the literature to search beneficial microbes for shrimp's health and found sequences for 42 species in our 16S data, being significantly increased Lactobacillus pentosus, Pseudomonas putida and Pseudomonas synxantha in the hepatopancreas of the AG10 and Rodopseudomonas palustris and Streptococcus thermophiles th1435 in the hepatopancreas of the AG2, both compared to BD. Interestingly, when we analyzed the abundance of 42 beneficial microbes as a single microbial community "meta-community," found an increase in their abundance as agavin concentration increases in the hepatopancreas. In addition, we also sequenced the DNA of agavin and found 9 of the 42 beneficial microbes. From those, Lactobacillus lactis and Lactobacillus delbrueckii were found in shrimps fed with agavin (both AG2 and AG10), and Lysinibacillus fusiformis in AG10 and they were absent the BD diet, suggesting these three species could be introduced with the agavin to the diet. Our work provides evidence that agavin supplementation is associated with an increase of beneficial microbes for the shrimp microbiota at farming conditions. Our study provides the first evidence that a shrimp prebiotic may selectively modify the microbiota in an organ-dependent effect.

Influence of bamboo vinegar powder (BVP) enriched diet on antioxidant status, immunity level, and pro-anti-inflammatory cytokines modulation in Asian sea bass, Lates calcarifer (Bloch 1790) against Vibrio anguillarum

Effect of bamboo vinegar powder (BVP) on growth, immunity, disease resistance, and immune-related gene expressions in juvenile Asian sea bass (barramundi), Lates calcarifer against Vibrio anguillarum was investigated. V. anguillarum infected fish fed by 2g BVP kg^-1 diet exhibited significant growth, albumin (AB), serum total protein (TP), and globulin (GB) levels. Similarly, enhanced lysozyme (LZM), phagocytic (PC), anti-protease (AP), respiratory burst (RB), bactericidal (BC) activities and total immunoglobulin (Ig) levels were observed in fish fed 2g BVP kg^-1. In addition, use of 2g BVP kg^-1 in diet modulated several immune related gene expressions against Vibrio disease. This study exhibited a positive effect of dietary 2g BVP kg^-1 diet on hemato-biochemical and immunological responses, which enhance the immunocompetence and health status of L. calcarifer against V. anguillarum infection.

Comprehensive investigations for a potential natural prophylaxis-A cellular and murine model for apple cider vinegar against hydrogen peroxide and scopolamine induced oxidative stress

Oxidative stress is the critical marker of neurological complications such as Alzheimer's disease (AD). Apple cider vinegar (ACV) is known to have health benefits due to its antidiabetic, anti-inflammatory, and high antioxidant properties. Therefore, we hypothesized that regular consumption of ACV would protect against AD-like neurological diseases via inhibition of oxidative stress. Authors have compared the efficacy of ACV with that of Chrysin and Rivastigmine in cellular and animal studies. In the cellular study, oxidative stress was induced in Neuro2A cells (1 × 10⁷ ) via H₂ O₂ (50 μM) treatment. Subsequently, acetylcholinesterase (AChE) activity was performed, and cell viability, SOD, GSH, lipid peroxidation (MDA) levels were measured. Similarly, in the animal study, oxidative stress was introduced in Swiss albino mice (10-11 weeks old, 20-25 g, n = 30) via scopolamine (1 mg/kg). Subsequently, histopathological experiments were performed; cognitive ability, AChE activity, and SOD, GSH, and MDA levels were measured. The in vitro results indicated that ACV (2 μM) provided better protection than Chrysin and Rivstigmine in cell viability. ACV has also performed better in restoring the antioxidants markers (SOD, GSH levels) and reducing MDA and AChE levels. In the in vivo study, test compounds (ACV, Chrysin, and Rivastigmine) improved cognitive impairment, increased the SOD and GSH level, reduced the MDA level and AChE activity, and protected the cortex-hippocampal neurons from degeneration. Here also, ACV (0.7%) showed better neuroprotection than the other two compounds. Therefore, these results supported our hypothesis that moderate consumption of ACV might prove to be beneficial prophylaxis against AD-like neurological diseases.

Selenium nanoparticle and selenomethionine as feed additives: effects on growth performance, hepatic enzymes' activity, mucosal immune parameters, liver histology, and appetite-related gene transcript in goldfish (Carassius auratus)

The aim of this study was to assess the effects of different dietary selenium sources, selenium nanoparticle (nSe), and selenomethionine (SeMet) as feed additives on growth performance, hepatic enzymes' activity, biochemical, mucosal immune parameters, liver histology, and appetite-related gene transcript in goldfish (Carassius auratus). At first, goldfish juveniles (n=480; mean 4.54 g) were fed dietary selenium nanoparticle at 0, 0.3, 0.6, and 0.9 mg nSe/kg diet and SeMet at 0, 0.3, 0.6, and 0.9 mg Se/kg for 9 weeks. Growth performance was evaluated using standard procedures. Blood, skin mucus, and tissue samples (liver and intestine) were collected for biochemical, mucosal immune response, histology, and ghrelin and insulin-like growth factor-I (IGF-I) gene expression. The results showed that fish fed diets fortified with 0.6 mg nSe/kg and 0.6 mg Se/kg had a significant higher weight gain, specific growth rates (SGR), and lower feed conversion ratios (FCR) than fish fed basal diets (p<0.05). Furthermore, dietary nSe and SeMet enhanced blood biochemical profiles especially alkaline phosphatase (ALP) (p < 0.05) and mucosal immunity than the control group in goldfish. Moreover, the liver histological investigation showed that fish fed 0.9 mg of SeMet and nSe kg^-1 diets had higher liver lesion scores such as karyolysis, lipidosis, and hyperemia while fish fed 0, 0.3, and 0.6 mg of SeMet and nSe kg^-1 diets had small liver changes at 9 weeks. The study further established that inclusion of nSe and SeMet in the diet of goldfish greatly promoted ghrelin and IGF-1genes expressions (p <0.05). Overall, dietary nSe performs better than SeMet and basal diets. The results evoked that nSe and SeMet stimulate the growth, biochemical, and mucosal immunity in goldfish at 0.6 mg/kg.

Antibacterial apple cider vinegar eradicates methicillin resistant Staphylococcus aureus and resistant Escherichia coli

Methicillin-resistant Staphylococcus aureus (MRSA) and resistant Escherichia coli (rE.coli) infections can spread rapidly. Further they are associated with high morbidity and mortality from treatment failure. Therapy involves multiple rounds of ineffective antibiotics alongside unwanted side effects, alternative treatments are crucial. Apple cider vinegar (ACV) is a natural, vegan product that has been shown to have powerful antimicrobial activity hence we investigated whether ACV could ameliorate these resistant bacteria. The minimum dilution of ACV required for growth inhibition was comparable for both bacteria (1/25 dilution of ACV liquid and ACV tablets at 200 µg/ml were effective against rE. coli and MRSA). Monocyte co-culture with microbes alongside ACV resulted in an increase in monocyte phagocytosis by 21.2% and 33.5% compared to non-ACV treated but MRSA or rE. coli stimulated monocytes, respectively. Label free quantitative proteomic studies of microbial protein extracts demonstrated that ACV penetrated microbial cell membranes and organelles, altering the expression of key proteins. This resulted in significant reductions in total protein expression, moreover we could only detect ribosomal proteins; 50 s 30 s, enolase, phosphenol pyruvate and the ATP synthase subunit in rE. coli. Elongation factor iNOS and phosphoglycerate kinase OS were the only proteins present in MRSA samples following ACV treatment.

Postbiotics Applications as Infectious Disease Control Agent in Aquaculture

Aquaculture is developing so fast that infectious disease outbreak happens regularly. Antibiotic treatment results in development of antibiotic resistance pathogens, thus cause urgent action in searching of other alternative treatment method. Postbiotic was one of the explored strategies among various proposed alternatives. Due to its benefits in agriculture industry, it may be useful in aquaculture industry. Although many reviews were reported on other alternative strategies, the review on postbiotic in aquaculture is limited. This mini review provides an overview of different postbiotics as aquaculture disease control agents. Peptides and exopolysaccharides have antimicrobial properties against bacterial pathogens. Then, short chain fatty acids have both antimicrobial activities against bacterial pathogens and immunostimulating effects to aquatic organism. Vitamins, peptidoglycan and lipopolysaccharide are reported as immunostimulants. Finally, cell surface proteins and teichoic acid can act as vaccine.

Improvement of non-specific immunity, growth, and activity of digestive enzymes in Carassius auratus as a result of apple cider vinegar administration to diet

This study was conducted to evaluate the effects of apple cider vinegar (ACV) administration on non-specific immunity of serum and skin mucus, growth indices, and activity of digestive enzymes (amylase, lipase, and protease) in Carassius auratus. For this purpose, 180 fish (weighing 7.35 ± 0.19 g) were allocated to 4 treatment groups with 3 replications in a completely randomized design. Fish were fed for 105 days using a basal diet supplemented with 0% (control), 1% (T 1), 2% (T 2), and 4% (T 3) ACV (contained 5% acetic acid). Results showed a significant increase in lysozyme activity, ACH50, and total immunoglobulin of skin mucus in fish fed with T2 diet (p < 0.05). Total immunoglobulin and lysozyme activity were significantly lower in the serum of fish fed with control diet than those fed with the mentioned treatment (p < 0.05). The highest value was observed in fish fed with T2 diet. Minimum (p < 0.05) complement activity (1.52 ± 0. 25 U ml^-1) was observed in fish fed with control diet. The mean of the final weights (17.35 ± 1.39 g), daily growth (1.0 ± 0.01 g), and specific growth rate (2.19 ± 0.14) was significantly higher in T3 diet group than the controls (p < 0.05). While the highest amylase-specific activity was observed in the controls (p < 0.05), there was a significant increase in specific activity of protease, lipase, and alkaline phosphatase in T2 diet group (p < 0.05). According to the results of this study, the inclusion of a limited quantity of ACV (4%) into the diet can improve immunity and growth parameters in C. auratus.

Effect of dietary supplementation with apple cider vinegar and propionic acid on hemolymph chemistry, intestinal microbiota and histological structure of hepatopancreas in white shrimp, Litopenaeus vannamei

This experiment was conducted to evaluate the effects of dietary supplementation of Apple cider vinegar (ACV) and propionic acid (PA) on biochemical parameters of hemolymph, intestinal microbiota and histology of hepatopancreas in white shrimp (Litopenaeus vannamei). Five experimental diets were evaluated in this study including diets supplemented with 1.0, 2.0 and 4.0% of ACV, 0.5% propionic acid, and a control diet with no supplements. Shrimps (initial weight of 10.2 ± 0.04 g) in triplicate groups with the density of 25 shrimps per tank were fed the diets for 60 days. At the end of the feeding trial, shrimps fed with ACV and PA supplemented diets had significantly higher total protein level than those fed the control diet (P < 0.05). The number of Vibrio spp., R-cells (lipid storage cells) of hepatopancreas and cholesterol level in shrimps fed the diets containing ACV and PA were lower compared to the control group (P < 0.05). However, there was no remarkable variations in glucose concentration, B-cell number and tubule diameter among the experimental diets (P > 0.05). In addition, shrimps fed the ACV diets had significantly lower total heterotrophic marine bacteria compared to the control or PA groups, and the lowest bacterial number was observed in shrimp fed 4% ACV supplemented diet (P < 0.05). Supplementation of 2 and 4% ACV as well as 0.5% PA in the diet led to a significantly higher calcium concentration than the control treatment (P < 0.05). The lowest triglyceride concentration was observed in the shrimps fed diets containing 2.0 and 4.0% ACV, which resulted in 15 and 20% reduction, respectively (P < 0.05). Overall, the findings indicates that ACV and PA possess antimicrobial activity and demonstrate beneficial effects on health status, so they can be potentially used as feed additive in the feeding of L. vannamei.

Trans-cinnamic acid application for rainbow trout (Oncorhynchus mykiss): I. Effects on haematological, serum biochemical, non-specific immune and head kidney gene expression responses

The present study investigated the effects of dietary trans-cinnamic acid (CA) on pre- and post-challenge haematological, serum biochemical, non-specific immune and head kidney gene expression responses of rainbow trout, Oncorhynchus mykiss juveniles. In this regard, fish with an average weight of 17.01 ± 0.05 g were divided into five groups, and fed daily with an additive free basal diet (control); 250, 500, 750 or 1500 mg kg^-1 CA for a 60-day period. Fish were sampled every 20 days during the experiment. On days 20, 40 and 60 (the pre-challenge period), the dietary CA especially at 250 and/or 500 mg kg^-1 significantly increased blood granulocyte percentage, and serum total protein, globulin, lysozyme and total immunoglobulin values. Furthermore, dietary CA increased activities of phagocytic activity, respiratory burst and potential killing, and increased the expression levels of immune related genes [serum amyloid A (SAA), interleukin 8 (IL-8), interleukin 1, beta (IL-1β), transforming growth factor beta (TGF-β), tumor necrosis factor (TNF-α), and immunoglobulin T (IgT)] in the head kidney of fish fed with 250 and/or 500 mg kg^-1 CA. Following 60 days of feeding, fish were challenged with Yersinia ruckeri and mortality was recorded for 20 days. Highest percentage survival (%) rate was found in the 250 and/or 500 mg kg^-1 CA-supplemented feeding groups. During the post-challenge period, red blood cell (RBC) count, hematocrit (%), respiratory burst activity, and total antiprotease activity increased in fish fed with feed containing 500 mg kg^-1 content. Moreover, markedly up-regulated the expression of related genes (SAA, IL-8, IL-1β, TGF-β, TNF-α, IFN-γ and IgM) in fish fed 250, 500 and/or 750 mg kg^-1 CA. Therefore, feeding O. mykiss for 60 days with dietary CA at 250-500 mg kg^-1 CA incorporation levels can be suggested as optimal to enhance the immunity and disease resistance against Y. ruckeri.

Dietary effects of succinic acid on the growth, digestive enzymes, immune response and resistance to ammonia stress of Litopenaeus vannamei

Organic acids acts as an growth promoter and antimicrobial agent in aquaculture. The present study investigated the effects of a natural organic acid - succinic acid (SA) on the growth, digestive enzymes, immune response and resistance to ammonia stress of Litopenaeus vannamei. The shrimps were firstly fed with diets containing different levels of SA: 0% (Control), 0.25% (SA1), 0.50% (SA2), and 1.0% (SA3) (w/w) for 56 days, followed by an acute ammonia stress for 48 h. The results indicated that dietary of SA improved the growth of shrimp, and increased the survival rate of shrimp after ammonia stress for 48 h. The amylase, lipase and pepsin activity increased in hepatopancreas in three SA group, while trypsin activity was only increased in the SA1 and SA2 groups. At 56 d, T-NOS activity, proPO and HSP70 gene expression level increased in the three SA group, PO activity increased in the SA1 and SA2 groups, T-AOC content and Toll gene expression level increased in the SA2 and SA3 groups, Trx and SOD gene expression level increased in the SA2 group, while Imd, GS and GDH gene expression level was no changes. After exposure to ammonia stress for 48 h, immune biochemical parameters (T-AOC and PO) and genes (proPO, HSP70, Trx and GDH) expression level increased in the three SA group, T-NOS activity, Toll, Imd and GS gene expression level increased in the SA2 and SA3 groups, while SOD gene expression level increased in the SA1 and SA2 groups. These results indicated that SA improved growth, enhanced digestive and immune capacities of L. vannamei against ammonia stress, and may be a potential feed additive for shrimp. The optimal dietary supplementation dosage is 0.50% (w/w) in diet.

Antimicrobial activity of apple cider vinegar against Escherichia coli, Staphylococcus aureus and Candida albicans; downregulating cytokine and microbial protein expression

The global escalation in antibiotic resistance cases means alternative antimicrobials are essential. The aim of this study was to investigate the antimicrobial capacity of apple cider vinegar (ACV) against E. coli, S. aureus and C. albicans. The minimum dilution of ACV required for growth inhibition varied for each microbial species. For C. albicans, a 1/2 ACV had the strongest effect, S. aureus, a 1/25 dilution ACV was required, whereas for E-coli cultures, a 1/50 ACV dilution was required (p < 0.05). Monocyte co-culture with microbes alongside ACV resulted in dose dependent downregulation of inflammatory cytokines (TNFα, IL-6). Results are expressed as percentage decreases in cytokine secretion comparing ACV treated with non-ACV treated monocytes cultured with E-coli (TNFα, 99.2%; IL-6, 98%), S. aureus (TNFα, 90%; IL-6, 83%) and C. albicans (TNFα, 83.3%; IL-6, 90.1%) respectively. Proteomic analyses of microbes demonstrated that ACV impaired cell integrity, organelles and protein expression. ACV treatment resulted in an absence in expression of DNA starvation protein, citrate synthase, isocitrate and malate dehydrogenases in E-coli; chaperone protein DNak and ftsz in S. aureus and pyruvate kinase, 6-phosphogluconate dehydrogenase, fructose bisphosphate were among the enzymes absent in C.albican cultures. The results demonstrate ACV has multiple antimicrobial potential with clinical therapeutic implications.

Apple cider vinegar boosted immunomodulatory and health promoting effects of Lactobacillus casei in common carp (Cyprinus carpio)

The present study was performed to investigate the immunomodulatory and health promoting effects of combined or singular administration of apple cider vinegar (ACV) and Lactobacillus casei in common carp (Cyprinus carpio) diet. An 8-week feeding trial was designed with following treatments: Control (basal diet), Pro (contains 10⁷ CFU g^-1L. casei), LACV (contains 1% ACV), HACV (contains 2% ACV), Pro + LACV (contains 10⁷ CFU g^-1L. casei plus 1% ACV) and Pro + HACV (contains 10⁷ CFU g^-1L. casei plus 2% ACV). Evaluation of skin mucus revealed notable increase of total Ig level and lysozyme activity in Pro + LACV and Pro + HACV treatments compared other groups (P < 0.05). Similarly, serum total Ig and lysozyme activity in HACV, Pro + LACV and Pro + HACV fed carps was remarkably higher than other groups (P < 0.05). However, regarding serum alternative complement (ACH50) activity significant difference was observed just between Pro + HACV and control treatment (P < 0.05). The highest expression of immune related (LYZ, TNF-alpha, IL1b, IL8) and antioxidant enzymes genes (GSR, GST) were observed in carps fed Pro + HACV and Pro + LACV. The expression of GH gene expression in Pro, LACV and HACV treatments was significantly higher than those in control group (P < 0.05). The highest expression level of GH and IGF1 was observed in fish fed combined Pro and ACV (P < 0.05). These results indicated that co-administration of ACV boosted immunomodulatory and health promoting effects of L. casei and can be considered as a promising immunostimulants in early stage of common carp culture.