Current research on the use of plant-derived products in farmed fish

Over the years, aquaculture has shown increasing development in terms of production. However, due to intensive farming practices, infectious diseases represent the main problem in fish farms, causing heavy economic losses. The use of antibiotics for controlling diseases is widely criticized for its negative impact, including selection of antibiotic-resistant bacterial strains, immunosuppression, environmental pollution and accumulation of chemical residues in fish tissues. On the other hand, though vaccination is the most effective prophylactic method of preventing disease outbreaks, the development of effective formulations is often hindered by high production costs and the antigenic heterogeneity of the microbial strains. Recently, there has been increased interest in the possibility of using medicinal herbs as immunostimulants, capable of enhancing immune responses and disease resistance of cultured fish. Plant-derived products seem to represent a promising source of bioactive molecules, being at the same time readily available, inexpensive and biocompatible. The aim of this article is to provide an overview of recent research dealing with the use of medicinal plants in aquaculture. Special attention is given to the information about the effects of plant extracts/products on fish growth, haematological profiles, immune responses and resistance to infectious diseases

First report on proliferative kidney disease (PKD) in marble trout (Salmo trutta marmoratus, Cuvier 1817)

Proliferative kidney disease is a hyperplastic response of the principal lymphoid tissue of salmonid fish infected by Tetracapsidoides bryosalmonae, a myxozoan parasite. This parasite affects many rainbow trout farms in Europe and North America. The disease has also been reported in other salmonids as well as in pike (Esox lucius) and grayling (Thymallus thymallus). In autumn 2000, an outbreak of PKD induced mortality in a group of marble trout (Salmo trutta marmoratus) juveniles reared in a farm in north-east Italy. The fish were intended to restock public waters. Diseased fish showed a lethargic behaviour, skin darkening, abdominal dilatation, gill anaemia and, after necroscopy, increase in volume and a pale colour of the kidney. All fishes subjected to histological examination showed a marked granulomatous interstitial nephritis, as well as foci of pancreatic and hepatic necrosis. The immunohistochemistry and PAS stain allowed visualisation of the extrasporogonic phase of the parasite Tetracapsuloides bryosalmonae in several tissues of the host. This is the first reported outbreak of PKD in marble trout, and should receive full attention since this species is potentially under risk of extinction

Novel Therapeutic Approach for the Management of Mood Disorders: In Vivo and In Vitro Effect of a Combination of L-Theanine, Melissa officinalis L. and Magnolia officinalis Rehder & E.H. Wilson

Mood disorders represent one of the most prevalent and costly psychiatric diseases worldwide. The current therapies are generally characterized by several well-known side effects which limit their prolonged use. The use of herbal medicine for the management of several psychiatric conditions is becoming more established, as it is considered a safer support to conventional pharmacotherapy. The aim of this study was to investigate the possible anxiolytic and antidepressant activity of a fixed combination of L-theanine, Magnolia officinalis, and Melissa officinalis (TMM) in an attempt to evaluate how the multiple modulations of different physiological systems may contribute to reducing mood disorders. TMM showed an anxiolytic-like and antidepressant-like activity in vivo, which was related to a neuroprotective effect in an in vitro model of excitotoxicity. The effect of TMM was not altered by the presence of flumazenil, thus suggesting a non-benzodiazepine-like mechanism of action. On the contrary, a significant reduction in the effect was observed in animals and neuronal cells co-treated with AM251, a cannabinoid receptor type 1 (CB1) antagonist, suggesting that the endocannabinoid system may be involved in the TMM mechanism of action. In conclusion, TMM may represent a useful and safe candidate for the management of mood disorders with an innovative mechanism of action, particularly as an adjuvant to conventional therapies

Growth parameters, innate immune response and resistance to Listonella (Vibrio) anguillarum of Dicentrarchus labrax fed carvacrol supplemented diets

The research was aimed to assess the effect of dietary carvacrol (0.025% and 0.05%) on sea bass (Dicentrarchus labrax) growth, immune response and resistance to Listonella anguillarum. Fish (69.2 ± 0.22 g) were fed the experimental diets for 9 weeks. Dietary carvacrol did not negatively affect fish survival, growth performance, feed intake and feed conversion ratio (P > 0.05) nor carcass yield and viscerosomatic, hepatosomatic and mesenteric fat index (P > 0.05). Serum and head kidney leucocytes were collected after 1, 4 and 8 weeks of feeding. Carvacrol significantly reduced serum proteins, immunoglobulins and lysozyme activity (P < 0.01) and moderately increased phagocytosis and pinocytosis of head kidney macrophages. The release of reactive oxygen species by leucocytes was reduced in carvacrol-fed fish, even if significantly (P < 0.05) only in those fed 0.05% carvacrol for 1 week. Dietary carvacrol did not significantly affect the aspecific immune response, although a potential antioxidant activity might be speculated. Moreover, feeding carvacrol provided an appreciable resistance to a challenge with L. anguillarum, when a bacterial dose lower than the Lethal Dose50 was used. Cumulative mortality in fish fed 0.025% carvacrol was significantly lower than that of untreated controls (75% Relative Per cent Survival)

Zingiber officinale Roscoe rhizome extract alleviates neuropathic pain by inhibiting neuroinflammation in mice

Background: Current therapies for neuropathic pain are generally symptomatic and possess several side effects, limiting their prolonged usage. Hypothesis/Purpose: Thus, it is urgent to develop novel and safe candidates for the management of this chronical condition. For this purpose, we investigated the analgesic effect of a standardized extract from Zingiber officinale Roscoe rhizomes (ZOE) obtained by CO2 supercritical extraction, in a mice model of peripheral neuropathy. We also explored the mechanism of action of ZOE and its main constituents using an in vitro model of neuroinflammation. Methods: Peripheral mono-neuropathy was induced in mice, by spared nerve injury (SNI). The analgesic effect of ZOE after oral administration was assessed by measuring mechanical and thermal allodynia in SNI mice. The mechanism of action of ZOE and its main constituents were investigated using spinal cords samples and in an in vitro model of neuroinflammation by ELISA, western blotting and immunofluorescence techniques. Results: Oral administration of ZOE 200 mg kg 121 ameliorated mechanical and thermal allodynia in SNI mice, with a rapid and a long-lasting effect. ZOE did not alter locomotor activity. In BV2 cells and spinal cord samples, ZOE, 6-gingerol and 6-shogaol reduced pERK levels, whereas ZOE and terpene fraction reduced HDAC1 protein levels, inhibited NF-\u3baB signalling activation and decreased IL-1\u3b2, TNF-\u3b1 and IL-6 release. ZOE and each tested constituent had a positive effect on inflammation-impaired SH-SY5Y cell viability. Conclusions: The oral administration of ZOE attenuated SNI-induced neuropathic pain symptoms by reducing spinal neuroinflammation, suggesting ZOE as a novel and interesting candidate for the management of neuropathic pain

Quality and Safety of Beef Produced in Central African Sub-Region

Aim of this research is to provide a general situation of cattle slaughtered in Cameroon, as a representative example for the Central African Sub-region. The quality and safety of beef from the abattoir of Yaoundé, the largest in Cameroon, were considered. From January 2009 to March 2012, the pre-slaughter conditions and characteristics of 1953 cattle carcasses were recorded, as well as the pH of m. longissimus thoracis 24 h after slaughter. From these carcasses, 60 were selected to represent the bulls slaughtered. The quality parameters and composition of m. longissimus thoracis were carried out. The origin of most of the cattle was the Guinea High Savannah (74.6%), and transhumance was the common production system (75.5%). Gudali (45.6%), White Fulani (33.3%) and Red Mbororo (20.3%) breeds were predominant. Carcass weight was affected by rearing system and cattle category, and it markedly varied during year. Considering meat quality, the fat content was low (1.2%) and similar between breeds, moreover Gudali showed the toughest meat. Of the cows slaughtered, 27% were pregnant and the most common abnormal conditions encountered were ectoparasites, fatigue, lameness, fungal-like skin lesions, enlarged lymph nodes, respiratory distress, nodular lesions. More than 20% of the carcasses had some organs condemned, mainly for liver flukes (5.17%), and 1.0% of them were completely condemned due to tuberculosis, that also affected 3.28% of lungs. These data could aid authorities draw up programmes with the aim to strengthen cattle production, improve beef supply, control and prevent the observed diseases, and promote the regional trade

Understanding the Pathogenesis of Red Mark Syndrome in Rainbow Trout (Oncorhynchus mykiss) through an Integrated Morphological and Molecular Approach

Red mark syndrome is a non-lethal widespread skin disease mainly reported in rainbow trout and caused by a Midichloria-like organism. Despite extensive research, its etiology and pathogenesis are still uncertain. In the present study, the authors used an integrated morphological and molecular approach, including gene expression, to elucidate the immune response and the complex immune interaction between the host and Midichloria-like organism. The results lead to the conclusions that the most severe skin lesions were characterized by a high level of inflammatory cytokines sustaining and modulating the severe inflammatory process. In contrast, in the moderate form, the response was driven to produce immunoglobulins and IL-10 to control the severity of the disease. Humoral immunity elicited during MLO infection appeared to have a fundamental role in controlling the severity of the skin disease, possibly through bactericidal antibody-mediated mechanisms

Rhabdomyosarcoma of Soft Tissues in an Adult Brook Trout (Salvelinus fontinalis)

This report describes a spontaneously arising rhabdomyosarcoma of soft tissues in a brook trout (Salvelinus fontinalis). The lesion was examined by means of histology, immunohistochemistry (IHC) and transmission electron microscopy (TEM). The cross-reactivity of the primary antibodies used in the IHC was investigated in silico using the Protein Blast system. Microscopically, the lesion appeared as a 'small round cell' undifferentiated sarcoma with rare myotube formation. IHC identified expression of sarcomeric actin and vimentin and these molecules showed the highest protein sequence identity. Lower protein sequence identity coincided with negative immunolabelling for desmin, MyoD1, myogenin and CD3. TEM revealed myofibrils, but without a defined sarcomeric architecture. The diagnosis of solid alveolar rhabdomyosarcoma of soft tissues was achieved on the basis of histological and ultrastructural finding

Protein Tyrosine Phosphatase Gamma (PTPγ) is a Novel Leukocyte Marker Highly Expressed by CD34+ Precursors

Protein Tyrosine Phosphatase gamma (PTPγ) is a receptor-like transmembrane protein belonging to the family of classical protein tyrosine phosphatases. PTPγ is known to regulate haematopoietic differentiation in a murine embryonic stem cells model. We have recently demonstrated that PTPγ mRNA is expressed in monocytes, tissue-localized myeloid dendritic cells and in both myeloid and plasmacytoid dendritic cells in peripheral blood. We now developed a PTPγ specific antibody that recognizes the protein by flow cytometry. PTPγ expression was detected in monocytes and both myeloid and plasmacytoid dendritic cells, while PMN showed a low but consistent staining in contrast with previous mRNA data. B cells were found to express the phosphatase while T cells were negative. In keeping with RNA data, PTPγ was detected in monocyte-derived dendritic cells and its expression rose upon LPS stimulation. Finally, we discovered that CD34+ haematopoietic precursors express high PTPγ level that drops during in vitro expansion induced by IL-3 and SCF growth factors. We therefore propose PTPγ as a new functionally regulated leukocyte marker whose role in normal and pathological context deserve further investigation

Computational modeling of immune system of the fish for a more effective vaccination in aquaculture

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