Effect of Dietary Herbal Supplements on Some Physiological Conditions of Sea Bass Dicentrarchus labrax

Abstract

This study was conducted in order to investigate the effects of dietary thyme Thymus vulgaris, rosemary Rosmarinus officinalis, and fenugreek Trigonella foenum graecum as feed additives on total liver fat levels and biometric indices of Sea Bass Dicentrarchus labrax. Four isonitrogenous (48% crude protein) and isocaloric (21 kJ/g) diets were formulated to contain 0% (control), or 1% of thyme, rosemary, or fenugreek. In a 45-d feeding trial, 12 fiberglass tanks (140 L) were each stocked with 17 fish (20.43 ± 0.03 g). Herbal supplemented diets significantly decreased the total liver fat, visceral fat index, viscerosomatic index, hepatosomatic index, and increased the spleen–somatic index and bile–somatic index (P < 0.05). In conclusion, the results indicated that a dietary level of 1.0% for thyme, rosemary, or fenugreek could improve some of the physiological parameters of Sea Bass. Thus, this work provides a new perspective for the use of medicinal herbs that can be added to fish feed to improve the status of fish organs. Thyme, rosemary, and fenugreek contain a number of different active components, which possibly play an important role in improving these conditions, but the mechanism by which this is achieved needs further and more detailed study.

Received July 19, 2012; accepted January 15, 2013     

Experimental Transmission and Pathogenicity of a Viral Erythrocytic Infection in Sea Bass Dicentrarchus labrax

Abstract

The experimental transmission of a viral erythrocytic infection (VEI) in sea bass Dicentrarchus (=Morone) labrax of the Mediterranean is reported. Transmission procedures included the intraperitoneal inoculation of healthy fishes with blood and hematopoietic tissue extracts from VEI-affected fishes, direct contact between VEI-affected and unaffected fishes, and rearing of fishes in unfiltered, nonirradiated seawater that had been used for holding VEI-affected fishes. Successful transmission of the infection was achieved in all experimental conditions, as ascertained by the presence of inclusion bodies in Giemsa-stained blood cells and subsequently confirmed by indirect immunofluorescent staining. Transmission of VEI by the inoculation of filtered cell-free extracts from affected tissues confirmed not only the infectious character of the disease but also its viral etiology. Two different patterns of effects on the hematological variables were observed: an erythroblastic polycythemia occurred 3 months after infection, whereas a moderate anemia appeared after 5–6 months. Fish growth was also negatively affected by VEI. Sea bass infected with VET were found to be more susceptible to bacterial challenge infection with Vibrio anguillarum isolate AO 18 than were control fish; the V. anguillarum dose that was lethal to 50% of the test fish was lower for VEI-affected fish, and their cumulative mortality in the bacterial challenge was higher. The injection of cyclophosphamide produced immunosuppression in unaffected sea bass and an increase in the level of infection in VEI-affected fishes; these results suggest the role of the immunological status of the host sea bass in the development of VEI.     

Effects of Garlic and Ginger Oils on Hematological and Biochemical Variables of Sea Bass Dicentrarchus labrax

Abstract

This study was conducted to investigate the effects of garlic and ginger oils on hematological and biochemical health characteristics of sea bass Dicentrarchus labrax. Fish were exposed to garlic oil (0.01 or 0.02 mL/L), ginger oil (0.01 or 0.02 mL/L), or a combination of the two oils (each oil at a concentration of 0.005 or 0.01 mL/L) for 96 h via bath immersion. Results showed that the red blood cell count, hematocrit (%), hemoglobin (Hb) concentration (g/dL), mean corpuscular volume (μm³), mean corpuscular Hb (pg), and mean corpuscular Hb concentration (%) were not significantly affected by herb oil exposure. However, some changes in biochemical variables were observed. Sea bass exposed to the 0.005-mL/L garlic oil–ginger oil mixture exhibited a significant increase in serum glucose. Serum total protein and albumin levels decreased in sea bass that were exposed to a garlic oil–ginger oil mixture (0.005 or 0.01 mL/L) or to garlic oil at 0.02 mL/L. Serum globulin levels decreased and triglyceride levels increased in sea bass exposed to 0.02-mL/L garlic oil or to the 0.01-mL/L mixture. The serum lipase level decreased and the cholesterol level increased in fish that were exposed to 0.02-mL/L garlic oil. In summary, ginger oil at 0.01–0.02 mL/L can be used without negative effects, while the garlic oil or garlic oil–ginger oil mixture should be applied at a concentration below 0.005 mL/L for bath immersion of sea bass. This is the first study to examine how garlic oil and ginger oil exposure via bath immersion affects the hematological and biochemical status of sea bass.

Received March 19, 2012; accepted July 2, 2012     

The Post-larval Development of Lateral Musculature in Gilthead Sea Bream Sparus aurata (L.) and Sea Bass Dicentrarchus labrax (L.)

Fibre-type differentiation of lateral musculature has been studied in gilthead sea bream Sparus aurata (L.) and sea bass Dicentrarchus labrax (L.) during post-larval development using ultrastructural, histochemical and morphometric techniques. The study showed three muscle layers: red, intermediate (or pink) and white. Initially, most of the red muscle showed low myosin ATPase (m-ATPase) activity fibres, whereas near the transverse septum some small high m-ATPase activity fibres appeared and later acquired a rosette aspect. Afterwards, during adult growth the red muscle showed a histochemical mosaic appearance. The pink muscle in sea bass was observed at the beginning of juvenile development by the oxidative technique (NADH-RT reaction) whereas in gilthead sea bream it was also observed at the end of larval development. The pink layer consists of high m-ATPase activity fibres. However, along the muscle development other low and moderate m-ATPase activity fibres were observed close to the red and white muscles, respectively. The white muscle of juvenile fish showed a histochemical mosaic appearance near the pink muscle. In adult specimens the mosaic white muscle spread out occupying the whole of the myotome. Morphometric analysis shows a significant increase in mean fibre diameter during post-larval development, as shown by the Student's t-test (hypertrophic growth). Skewness and kurtosis values of fibre diameters point to the generation of a new fibres from the myosatellite cells (hyperplastic growth).     

Growth Dynamics of White Muscle Fibres in Relation to Somatic Growth of Larvae of European Sea Bass (Dicentrarchus labrax, L.)

The body length and diameter of muscle fibres from the right hypaxial tail myomeres were measured in 100 sea bass larvae (Dicentrarchus labrax, L.) at ages of 40 to 90 days, from a fish farm in Croatia. The larvae were kept at a temperature of 19-20 degrees C and fed with standard feed for their respective ages. Body lengths of larvae 40-90 days old varied from 8 to 42 mm, increasing significantly in 10-day intervals (p < 0.001), except between days 50 and 60 when there was no increase in the body length. The measured diameters of muscle fibres ranged from 10 to 80 microm, the mean value increasing except between days 50 and 60. The fibre diameter in larvae aged up to 60 days was 10-40 microm, while that in larvae older than 70 days was 51-80 microm. In 90-day-old larvae there were no fibres of 10-20 microm in diameter; however, the number of fibers of 61-80 microm diameter increased. A statistically significant concordance was determined between the body length and fibre diameter of larvae 70 to 90 days old. Between days 50 and 60, arrested growth of the larval body and corresponding decrease in fibre diameter was observed. From day 45 until days 59, larvae were fed with Artemia nauplii and microparticles of formulated diets. From the day 60, minced fish was added to formulated diets. This change in diet probably resulted in the observed growth arrest.     

Muscle Development in Gilthead Sea Bream (Sparus aurata, L.) and Sea Bass (Dicentrarchus labrax, L.): Further Histochemical and Ultrastructural Aspects

The histochemical profiles - mATPase and NADH-TR reactions - of the red and white muscle fibres of gilthead sea bream and sea bass were determined from the first week after hatching. Modifications of the mATPase technique by combinations of pH/time/molarity were carried out in order to compare the sensitivity of the myosin ATPase of each muscle fibre type of the lateral muscle. Results showed that the staining of muscle fibres was independent of small modifications in the technique. The intermediate ‘pink’ muscle was histochemically defined towards the end of the larval life and is considered to be implicated in the growth of the myotome. A layer of external cells was observed, by electron microscopical examination, between the connective tissue of the skin and the superficial red muscle fibres of larvae and postlarvae. It is suggested that the external cells are unlikely to be a source of red muscle fibres and implicated on the growth of the myotome, but rather a part of the dermatome. The timing, areas and mechanisms of hyperplastic growth of the myotome were defined and discussed.     

Effect of long-term oral administration of an immunostimulant diet on innate immunity in sea bass (Dicentrarchus labrax)

Immunostimulants represent a modern and promising tool in aquaculture, enhancing the resistance of cultured fish to disease and stress. This study investigated the effect of a combination of dietary glucans, alpha-tocopherol and ascorbic acid on the innate immune response of cultured sea bass (Dicentrarchus labrax). After 5 weeks of adaptation on a commercial diet containing 100 p.p.m. ascorbic acid and 200 p.p.m. alpha-tocopherol, sea bass were switched to a diet supplemented with 2% beta-1.3/beta-1.6 glucans and ascorbic acid and alpha-tocopherol at 500 p.p.m. The supplemented diet was given at 2% of body weight per day over a 2-week period, every 3 months. Plasma lysozyme concentration, content and distribution of major plasma proteins and complement activity were measured prior to feeding the supplemented diet and after 40 weeks. Alternative pathways of complement activation and lysozyme activity were both significantly enhanced in fish fed on glucans and elevated doses of vitamins. No significant differences were observed in protein content or in albumin/globulin ratio. Compared to lysozyme activity, which showed marked individual variation, complement-mediated haemolytic activity has been shown to be a more reliable indicator of sea bass immunocompetence. Further studies are in progress to clarify the effect of each dietary component on the innate immune response and disease resistance.     

Comparison of the API 20E and BBL Crystal E/NF Identification Systems for Differentiating Bacterial Isolates from Apparently Healthy Reared Sea Bass (Dicentrarchus labrax)

The ability of two commercial rapid identification systems, API 20E and BBL Crystal E/NF, to reliably identify bacterial isolates from the internal organs of reared sea bass were compared. The tests gave different results: API 20E identified bacteria as Pseudomonas spp. with 37% accuracy, while BBL Crystal E/NF identified them as Flavobacterium odoratum with 99% accuracy. Although F. odoratum is not a marine fish pathogen, conventional tests conducted with the same isolates were more indicative of them being Flavobacterium spp. than Pseudomonas spp., suggesting that BBL Crystal E/NF was more reliable in this identification. Both systems were found to be applicable for diagnostics of marine fish pathogens, but should be used with caution because of possible misinterpretation.     

Blood Chemistry and Histological Properties of Wild and Cultured Sea Bass (<Emphasis Type="Italic">Dicentrarchus labrax</Emphasis>) in the North Adriatic Sea

Histological and biochemical procedures were employed to study liver histomorphology and plasma levels of aspartate aminotransferases (AST), alanine aminotransferase (ALT), triglyceride (TRIG), cholesterol (CHOL), glucose (GLU) and total protein (TP) in cultured (CSB) and wild sea bass (WSB) (Dicentrarchus labrax) from the northern part of the Adriatic Sea. Histopathological changes in liver included varying degrees of infiltration and lipid degeneration of hepatocytes in examined cultured fish. No significant differences between median AST values of CSB (44 IU) and WSB (45 IU) were observed. Values of ALT were <5 IU in both groups. TRIG, CHOL, GLU and TP levels were higher in CSB (2.08 mmol/L, 3.67 mmol/L, 10.66 mmol/L and 49 g/L, respectively) than in WSB (0.67 mmol/L, 2.74 mmol/L, 3.68 mmol/L and 36 g/L, respectively). The study showed differences between plasma biochemical parameters and liver histomorphology of CSB and WSB. This can be explained as a consequence of different diets (artificial in contrast to natural foods), which influence energy metabolism.     

Demonstration of natural killer cells (NK) in the breeding perch (Dicentrarchus labrax). Effect of breeding temperature

The role of temperature on NK cells was studied in the spleen of a fish (Dicentrarchus labrax). NK cells presence was demonstrated with a maximal cytotoxicity when animals were maintained at 18°C. An in vitro study confirmed these results.     

Gill morphology in two Mediterranean Sea fishes of similar feeding preferences: sea bream (Sparus aurata L) and sea bass (Dicentrarchus labrax)

The aim of the present study was to describe the gill morphology of the gilthead sea bream and sea bass fishes that showed the same feeding habits. Our study focused on the gross morphological, scanning and light microscopical features of the gills, where a many differences in the gill arches and gill rakers surface in both species were explained. Our results marked that; there was an interbranchial median elevation appeared in sea bream. The gill arches length and the gaps between decreased medial wards in both species. The gill rakers had similar arrangement and varied number in both species. The first lateral rakers row was the longest one in sea bass. However the gill filaments appeared in double rows. Gill filaments were long at middle and short at extremities of gill arch in both species. Scanning electron microscopy revealed the surfaces of gill arch covered by a mosaic of pavement cells, varied sized pores of chloride cells and many pointed spines on the rakers ventral border in both species. Two types of taste buds marked on the gill arches and rakers in sea bass. Many lamellae appeared on filaments in both species.     

MDA5在先天性免疫抗病毒作用中的研究进展

黑色素瘤分化相关基因5(melanoma differentiation-associated gene-5,MDA5)是胞浆内核酸受体,与病原相关分子模式(pathogen-associated molecular patterns,PAMPs)相结合,特异性地识别较长的双链RNA,功能与视黄酸诱导表达基因Ⅰ(retinoic acid-inducude gene Ⅰ,RIG-Ⅰ)相似,通过自身级联激活和招募结构域(CARD)与接头蛋白CARD同源相互作用之后,与接头蛋白线粒体连接蛋白(MAVS)(也叫VISA、Cardif或IPS-1)结合,相互作用后会导致RIG-Ⅰ样受体(RLR)在内膜上重新定位,一边招募来TRAF2/TRAF6活化IKK激酶复合物,从而激活转录因子NF-κB;另一边招募来TRAF3和TBK1,从而促进IRF3的磷酸化激活,活化后的转录因子NF-κB及IRF会进入细胞核,共同协作促进Ⅰ型干扰素基因的表达.     

Comparison of Efficacy of Long‐term Oral Treatment with Telmisartan and Benazepril in Cats with Chronic Kidney Disease

Background

The efficacy and benefits of telmisartan in cats with chronic kidney disease (CKD) have not previously been reported.

Hypothesis

Long‐term treatment of cats with CKD using telmisartan decreases urine protein‐to‐creatinine ratio (UP/C) similar to benazepril.

Animals

Two‐hundred and twenty‐four client‐owned adult cats with CKD.

Methods

Prospective, multicenter, controlled, randomized, parallel group, blinded clinical trial with noninferiority design. Cats were allocated in a 1 : 1 ratio to either telmisartan (1 mg/kg; n = 112) or benazepril (0.5–1.0 mg/kg; n = 112) PO q24 h. The primary endpoint was prospectively defined as the change in proteinuria (benazepril:telmisartan) based on a log transformed weighted average of UP/C change from baseline (AUC 0→t/t) as a percentage compared using a confidence interval (CI) approach. Changes of UP/C from baseline were assessed on all study days and corrected for multiple comparisons.

Results

Telmisartan proved noninferior to benazepril in controlling proteinuria (CI, −0.035 to 0.268). At Day 180, UP/C compared to baseline in the telmisartan group was significantly lower (−0.05 ± 0.31; P = .016), whereas in the benazepril group the change (−0.02 ± 0.48) was not statistically significant (P = .136). Similar results were obtained at all assessment points with significant decrease in UP/C occurring with telmisartan but not benazepril.

Conclusion and Clinical Importance

Both telmisartan and benazepril were well tolerated and safe. Telmisartan proved to be noninferior to benazepril and significantly decreased proteinuria relative to baseline at all assessment points whereas benazepril did not.     

Methicillin‐resistant Staphylococcus aureus in Resident Animals of a Long‐term Care Facility

Animals provide benefits to elderly and chronically ill people by decreasing loneliness, increasing social interactions, and improving mental health. As a result, many hospitals and long‐term care facilities allow family pets to visit ill or convalescing patients or support animal‐assisted therapy programs. These include programs that have resident animals in long‐term care facilities. Despite the benefits, there are concerns about disease transmission between pets and patients. Antibiotic‐resistant bacteria, such as methicillin‐resistant Staphylococcus aureus (MRSA), are a recognized problem in healthcare settings leading to refractory infections and potentially life‐threatening illnesses. MRSA has been isolated from numerous animal species, yet few studies are available on the carriage of this pathogen in animals residing in long‐term care facilities. Our objective was to characterize MRSA carriage among resident animals in a long‐term care facility. Methods: To document MRSA colonization, nasal swabs from 12 resident animals (one dogs and 11 cats) of a long‐term care facility were collected weekly for 8 weeks. Staphylococcus isolates were characterized by antimicrobial susceptibility and MRSA isolates were further characterized by pulsed‐field gel electrophoresis (PFGE). PFGE isolate patterns were compared with an existing database of MRSA isolate patterns at the Minnesota Department of Health. Results: Two of 11 cats were colonized with MRSA. MRSA was recovered from five of eight weekly samples in one cat and two of eight weekly samples in the other cat. All isolates were classified as USA100 (healthcare‐associated strains). Discussion: Long‐term care resident animals may acquire MRSA. Clonally related strains were identified over the 8‐week sampling period. It is unclear if pets serve as an on‐going source of infection to their human companions in long‐term care facilities.     

Long‐term administration of a commercial porcine reproductive and respiratory syndrome virus (PRRSV)‐inactivated vaccine in PRRSV‐endemically infected sows

The purpose of this study was to investigate the safety and efficacy of a commercial European porcine reproductive and respiratory syndrome virus (PRRSV)‐inactivated vaccine after 18‐month use in gilts/sows at a farm with high seroprevalence. In a farrow‐to‐finish farm with 1100 sows, all sows and gilts were systematically vaccinated with the PRRS‐inactivated PROGRESSIS® vaccine for a period of 18 months. Farm's reproductive and litter characteristics were longitudinally recorded for this period and historically compared with those of the year prior to vaccination. Serology, employing immunoperoxidase monolayer assay, had confirmed a high prevalence of PRRS‐specific antibodies in most age groups within the farm prior to vaccination. Seroprevalence during the experiment ranged between 0% and 100% in weaners and growers, but remained at stable high levels (>93%) in finishing pigs and gilts throughout all 2‐year period of serology measurements. No local or systemic vaccine side effects were noted throughout the trial period. Vaccinations had resulted over time in a significant improvement of sow reproductive performance (e.g. reduction of premature farrowings, abortions and increase of farrowing rate) and litter characteristics (e.g. increase of the number of live born and weaned pigs and decrease of stillborn, mummified, weak and splay‐legged piglets). It has also been observed that the higher the degree of immunization of a sow, the better the improvement of her reproductive parameters. Sows after vaccination have shown improved characteristics compared to homoparous sows prior to the application of vaccinations in the farm.