Intestinal histomorphology, autochthonous microbiota and growth performance of the oscar (Astronotus ocellatus Agassiz, 1831) following dietary administration of xylooligosaccharide

The present study investigates the changes in intestinal histomorphology, autochthonous microbiota and growth performance of the oscar, Astronotus ocellatus, following dietary administration of different levels of xylooligosaccharide (XOS). One hundred forty-four oscars (8.88 ± 0.23 g; n = 144) were randomly stocked in 12 aquaria (100-L) assigned to four treatments repeated in triplicate. Fish were fed a commercial diet, Biomar, supplemented with different levels (0 control, 0.5, 1, 2%) of XOS for 8 weeks. Treatments were investigated under static aerated water conditions with a 70% daily water exchange. Evaluation of intestinal histomorphology (villus height, enterocytes height and thickness of the tunica muscularis) revealed no significant differences between XOS-fed groups and the control treatment (P > 0.05). However, administration of XOS in the oscar diet increased the total autochthonous intestinal heterotrophic bacteria significantly (P < 0.05). Autochthonous lactic acid bacteria levels were also significantly elevated in XOS-fed groups (P < 0.05). Furthermore, dietary XOS remarkably increased growth performance (control: 22.76 ± 2.79, 2% XOS: 29.13 ± 2. 8; n = 12) parameters of the oscar (P < 0.05). These results demonstrated the beneficial effects of XOS on the growth performance and intestinal microbiota of A. ocellatus. © 2016 Blackwell Verlag GmbH

Effects of date palm fruit extracts on skin mucosal immunity, immune related genes expression and growth performance of common carp (Cyprinus carpio) fry

The aim of this study was to investigate the effects of date palm fruit extracts (DPFE) on skin mucosal immunity, immune related genes expression and growth performance of fry common carp (Cyprinus carpio). One hundred and twenty specimens (4.06 ± 0.13 g) were supplied and allocated into six aquaria; specimens in three aquaria were fed non-supplemented diet (control) while the fish in the other 3 aquaria were fed with DPFE at 200 ml kg-1. At the end of feeding trial (8 weeks) skin mucus immune parameters (total immunoglobulins, lysozyme, protease and alkaline phosphatase activity) and immune related gene expression (tumor necrosis factor α [tnfa], lysozyme [ly] and interleukin-1-beta, [il1b]) in the head-kidney were studied. The results revealed that feeding carp fry with 200 ml kg-1 DPFE remarkably elevated the three skin mucus immune parameters tested (P 0.05) compared to control fish (fed control diet). Furthermore, growth performance parameters were significantly improved in fry fed DPFE (P < 0.05). More studies are needed to understand different aspects of DPFE administration in fry mucosal immunity. © 2015 Elsevier Ltd

Probiotics, lactic acid bacteria and bacilli: interesting supplementation for aquaculture

Probiotics administration in aquafeed is known to increase feed consumption and absorption due to their capacity to release a wide range of digestive enzymes and nutrients which can participate in digestion process and feed utilization, along with the absorption of diet components led to an increase in host’s health and well‐being. Furthermore, probiotics improve gut maturation, prevention of intestinal disorders, predigestion of antinutrient factors found in the feed ingredients, gut microbiota, disease resistance against pathogens and metabolism. The beneficial immune effects of probiotics are well established in finfish. However, in comparison, similar studies are less abundant in the shellfish. In this review, the discussions will mainly focus on studies reported the last 2 years. In recent studies, native probiotic bacteria were isolated and fed back to their hosts. Although beneficial effects were demonstrated, some studies showed adverse effects when treated with a high concentration. This adverse effect may be due to the imbalance of the gut microbiota caused by the replenished commensal probiotics. Probiotics revealed greatest effect on the shrimp digestive system particularly in the larval and early post‐larval stages, and stimulate the production of endogenous enzymes in shrimp and contribute with improved the enzyme activities in the gut, as well as disease resistance

The effects of prebiotic oligofructose on hematological, serum biochemical parameters and liver enzymes of juvenile beluga (Huso huso)

The aim of the present study was to investigate the effects of dietary oligofructose (1, 2 and 3%) on blood profiles of beluga Huso huso juveniles (18.77±0.76g). After 7 weeks feeding on experimental diets hematological parameters, metabolic products (cholesterol, glucose and total protein) and serum enzymes (lactate dehydrogenase, alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase) were measured. Compared to the control group (0% oligfructose), oligofructose had no effects on red blood cell counts (RBC), mean corposcular volume (MCV), mean cellular hemoglobin concentration (MCH) or mean cell hemoglobin concentration (MCHC) (P>0.05). However, hematocrit (Hct), hemoglobin concentration (Hb) and leucocyte counts (WBC) were significantly higher in fish fed 2% oligofructose (P0.05). These results indicate an immunomodulatory effect and the potential to reduce serum cholesterol levels in beluga sturgeon

The effects of glucan on hematological parameters, immune response and intestinal microbiota of Rutilus frisii kutum fry

The purpose of this study was to determine the effect of dietary glucan on some haematological parameters, immune response and intestinal microbiota of Rutilus frisii kutum. In the present study, various levels of ingredient so called Hoplit (0, 0.5, 1.0, 1.5, and 2.0%) containing glucan was added to a basal formulated diet. Twenty and five kutum fry with a mean (±SD) weight of 1.15±0.06g were stocked in each experimental tank (100 l capacity) filled with 80 liter of water. Fish were fed on experimental diet for 56 days and biometry was performed every 15 days. At the end of the trial blood samples were collected for measurement of haematological parameters including: Red and white blood cells count, differential count of white blood cells, hematocrit and hemoglobin, and innate immune factors (Immunoglobulin and Lysozyme). Fries in 1.5% treatment had highest serum immunoglobins (Ig) and eosinophil, although when compared with control but with no significant differences. Highest MCHC, hematocrit and hemoglobin were observed in the 0.5 and 1% treatments and the highest MCV and red blood cell count were in 0.5 percent treatment. The highest white blood cells count and neutrophils was observed in 2% treatment. The highest and lowest levels of lysozyme activity were observed in 1% and control treatments, respectively. Evaluation of the total bacteria and LAB counts revealed significant increase in 0.5% treatment. According to these results administration of dietary glucan can be considered for stimulation of innate immune response of white fish fry

The probiotic effects of dietary inactive yeast Saccharomyces cerevisiae var. ellipsoideus on growth factors, survival, body composition and intestinal microbiota of Beluga juvenile (Huso huso)

The probiotic effects of inactive yeast, Saccharomyces cerevisiae var. ellipsoideus was studied on growth performance, survival and intestinal microbiota of beluga juveniles (Huso huso). The study was done in complete randomize design that included feeding of beluga juveniles with diets supplemented with 0 (control), 1, 2 and 5% yeast (4 treatments with 3 replicates). Beluga juveniles (11.40±0.56g) were randomly allocated in 12 oval tanks at a density of 35 fish per tank and triplicate group were fed with experimental diets. At the end of the trial, growth factors (final weight, weight gain, SGR, CF) as well as feed conversion ratio (FCR), body composition (protein, lipid, ash, moisture) and intestinal microbiota (total viable bacteria and Lactobacillus spp. levels) were determined. Our results confirmed that juveniles fed on diet supplemented with 5% S. cerevisiae var. ellipsoideus had significantly higher final weight, weight gain, specific growth rate (SGR) and lower food conversion ratio compared to control and 1% treatment (P0.05). The study of body composition showed no significant difference between treatments (P>0.05). Total viable bacteria and Lactobacillus spp. count were significantly higher in 5% treatment compared to control (P0.05)

Analysis and identification of Iranian shrimp hatcheries challenges

Risk identification and consideration are vital for the development and future planning of shrimp aquaculture. For surveying the production and development characteristics of shrimp hatcheries in Iran, a questionnaire was prepared based on international standards and references, and several stockholders of shrimp hatcheries were consulted. Results indicated feed, foreign technicians, and financial resources as the major challenges of Iranian shrimp hatcheries. The major objective of this research was to obtain the opinions and experiences of stockholders active in shrimp hatcheries in Iran. The identification of the present challenges of Iranian shrimp hatcheries was another objective of the study

Anesthetic efficacy and biochemical effects of citronellal and linalool in common carp (Cyprinus carpio Linnaeus, 1758) juveniles

Present study reports the anesthetic and biochemical effects of citronellal and linalool in common carp (Cyprinus carpio) juveniles (about 110 g). The fish were anesthetized with citronellal (200, 300, 400, 500, 600, 800, 1000 and 1200 mg/L) and linalool (200, 400, 600, 800, 1200, 1600, 2000 and 2400 mg/L) and their behavioral responses to anesthesia were recorded to determine anesthesia stages. Then, required concentration of each anesthetic was calculated to induce deep anesthesia within 5 min. The fish were exposed to these concentrations, along with 43 mg/L eugenol (as a reference anesthetic) for 5 min prior to blood sampling. In addition, the fish were exposed to 10 and 20 mg/L of either citronellal, linalool or eugenol for 3 h to find long-term effects of the compounds on fish blood health characteristics. At the concentration of 200 mg/L, both citronellal and linalool failed to induce deep anesthesia. Citronellal induced deep anesthesia within 457–114 s at the concentrations of 300–1000 mg/L; recovery time was 113–204 s. Further increase in citronellal concentration has no significant effects on the induction and recovery time. Linalool at the concentrations 400–2000 mg/L induced deep anesthesia within 467–118 s with recovery time of 174–215 s. Further increase in linalool concentration has no significant effects on the induction and recovery time. Increase in citronellal or linalool concentrations significantly decreased induction time of anesthesia with strong relationship. Short-term anesthesia with citronellal and linalool caused significantly lower AST and LDH activity compared to eugenol; however, long-term exposure to linalool caused higher AST and LDH activity compared to citronellal and eugenol. Plasma total protein and globulin levels of the citronellal- and eugenol-anesthetized fish were similar and significantly higher than that of the linalool-anesthetized fish. The present study demonstrated that citronellal is suitable for general fish handling, but not rapid blood sampling and surgery. Citronellal anesthetic efficacy was higher than linalool in the present study, but lower than other anesthetics previously used for carp fingerling anesthesia. Biochemical data after short-term anesthesia show that fish anesthetized with citronellal and linalool may experience lower tissue problems compared to eugenol; however, linalool had adverse effects on plasma protein and globulin levels compared to citronellal and eugenol. Under long-term exposure, linalool may cause higher tissue problems compared to citronellal and eugenol. Citronellal is less efficacious than eugenol for carp anesthesia, however is beneficial in the case of fish health as it causes less tissue problems. © 201

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−1 L. casei), LACV (contains 1% ACV), HACV (contains 2% ACV), Pro + LACV (contains 107 CFU g−1 L. casei plus 1% ACV) and Pro + HACV (contains 107 CFU g−1 L. 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. © 2017 Elsevier Lt

Non-specific immune parameters, immune, antioxidant and growth-related genes expression of common carp (Cyprinus carpio L.) fed sodium propionate

The present study investigates the effects of different levels (0, 0.5, 1 and 2) of sodium propionate (SP) on serum and mucus non-specific immune response as well as the expression of genes related to antioxidant enzymes, mucosal immunity and growth in common carp. Compared control group, skin mucus total Ig and lysozyme activity significantly increased in SP-fed fish (P 0.05). There was significant difference between control and SP treatments in case of serum immune parameters (P < 0.05). The highest serum total Ig levels and lysozyme activity were observed in 2 SP treatment. Evaluation of antioxidant and mucosal immune-related genes expression revealed notable upregulation in SP-fed carps with respect to the value found in fish from control treatment (P < 0.05). However, upregulation of those genes was more pronounced in 1 and 2 SP treatments. Also, transcript levels of IGF1 and GH were significantly upregulated along with the increasing SP inclusion level (P < 0.05). The present results revealed beneficial effects of SP inclusion (1 and 2) in carp diet on mucosal and non-specific immune responses as well as above-mentioned genes expression. © 2017 John Wiley & Sons Ltd