A new chlorosesquiterpene lactone from Ambrosia maritima

A new chloro-pseudoguaianolide-type sesquiterpene lactone, 11β-hydroxy-13-chloro-11,13-dihydrohymenin (1), was isolated from the Egyptian medicinal plant Ambrosia maritima. The structure was determined by spectroscopic methods, particularly high-resolution ¹H, ¹³C-NMR and 2D ¹H–¹H and ¹H–¹³C COSY NMR analysis.     

Dietary protein requirement of juvenile marbled spinefoot rabbitfish Siganus rivulatus

Rabbitfish are an Indo‐Pacific herbivorous marine fish that have good market demand and are suitable for aquaculture. The present work was performed to determine dietary protein inclusion necessary for optimal growth of juvenile rabbitfish Siganus rivulatus. Six diets with increasing levels of protein (10, 20, 30, 40, 50 and 60 g crude protein 100 g^?1 feed) and similar levels of gross energy (20 MJ kg^?1) were prepared and offered to S. rivulatus juveniles maintained in triplicate cages placed in two large water tanks for 49 days. Growth progressively improved with dietary protein for fish offered diets from 10% to 40% protein inclusion. Diets with greater protein levels did not improve fish growth beyond that observed in the 40% group. Daily feed intake, apparent protein utilization and feed conversion ratio decreased as dietary protein increased. Protein efficiency (PE) was greatest (1.47) in fish offered the 10% protein diet and least in fish offered the 60% protein diet (0.80). No differences in PE were observed among all other treatments (20–50%). Results of the present work suggest that minimum dietary requirement for suitable growth of S. rivulatus juveniles is 40% protein when digestible energy of the diet is 16–18 MJ kg^?1.     

The importance of dietary HUFA for meagre larvae (Argyrosomus regius; Asso, 1801) and its relation with antioxidant vitamins E and C

Despite the interest of meagre (Argyrosomus regius) as a fast‐growing candidate for Mediterranean aquaculture diversification, there is a lack of information on nutrition along larval development. Importance of highly unsaturated fatty acids (HUFA) and the antioxidant vitamins E and vitamin C has not been investigated yet in this species. Six diets with two levels of HUFA (0.4% and 3% dw), two of vitamin E (1500 and 3000 mg kg^?1) and two of vitamin C (1800 and 3600 mg kg^?1) were fed to 15 dah meagre larvae. Larval growth in total length and dry body weight was significantly lowest in larvae fed diet 0.4/150/180 and showed few lipid droplets in enterocytes and hepatocytes and lower HUFA contents than the initial larvae. Increase in dietary HUFA up to 3%, significantly improved larval growth and lipid absorption and deposition. Besides, among fish fed 3% HUFA, increase in vitamin E and vitamin C significantly improved body weight, as well as total lipid, 22:6n‐3 and n‐3 fatty acids contents in the larvae. Thus, the results showed that 0.4% dietary HUFA is not enough to cover the essential fatty acid requirements of larval meagre and a high HUFA requirement in weaning diets is foreseen for this species. Besides, the results also pointed out the importance of dietary vitamin E and C to protect these essential fatty acids from oxidation, increase their contents in the larvae and promote growth, suggesting high vitamin E and C requirements in meagre larvae (higher than 1500 and 1800 mg kg^?1 for vitamin E and vitamin C respectively).     

Differences in the effectiveness of reproduction among ten breeding strains of the common carp Cyprinus carpio L. after stimulation of ovulation with carp pituitary homogenate or [(D‐Ala6, Pro9NEt) mGnRH‐a + metoclopramide] (Ovopel)

This study focused on the reproduction effectiveness of 10 breeding strains of common carp (Polish strains 2, 3, 6; Hungarian strains 0, W, 7; Lithuanian strain B; French strain F; Israeli strain D and Yugoslavian strain J) after stimulation of ovulation with carp pituitary homogenate or Ovopel. The percentage of females with recorded ovulation became higher after Ovopel treatment in as many as eight breeding strains (2, 3, 6, 0, W, B, F, D). The interaction between the spawning agent and the breeding strain was statistically significant (P ≤ 0.05) for the mass of spawn and non‐significant for traits determining the quality of eggs. Among the 10 breeding strains, in 4 (3, 7, B, J) the least‐squares means (LSM) for the weight of egg (g) were higher for fish stimulated with Ovopel. Among the strains tested, in seven (3, W, F, J, 2, 7, B), the LSM for the percentage of living embryos after 36 h incubation were higher for fish treated with Ovopel. The evaluation of reproduction effects based on the values of such parameters as the percentage of ovulating females, weight of eggs (g) and the percentage of live embryos (36 h) showed that after Ovopel treatment the poorer effects were obtained only for strains 6, 0 and D.     

Effect of altering linoleic acid and linolenic acid dietary levels and ratios on the performance and tissue fatty acid profiles of Nile tilapia <Emphasis Type="Italic">Oreochromis niloticus</Emphasis> fry

This experiment was conducted to study the effect of altering the linoleic acid (LA) and linolenic acid (LNA) levels and ratios in the diet of Nile tilapia (Oreochromis niloticus) on fry performance. Twelve diets were formulated to be isonitrogenous, isocaloric, and differed only in their main lipid source. An oil rich in n-3 fatty acids [linseed oil (L)] and two oils rich in n-6 fatty acids [soybean oil (S) and corn oil (C)] were added at 6% of the basal diet either separately or in equal combinations (L1:S1 or L1:C1 or S1:C1) or at ratio 2:1 (L2:S1 or L2:C1 or C2:L1 or C2:S1 or S2:L1 or S2:C1). The fish were fed twice daily (09 and 16 h) to apparent satiation throughout the duration of the trial (16 weeks). Survival rates increased in a linear pattern with increasing the LA level in the diets (R ² = 0.764). Final body weight was significantly higher in fish fed S, S2:L1, and L2:C1 diets, being 14.29, 14.14, and 14.09 g/fish, respectively. However, tilapia fed C, S1:C1, and C2:S1 diets exhibited low final body weight (11.41, 11.60, and 11.76 g/fish, respectively). The final body weight was negatively affected by increasing the LA/LNA ratios (R ² = 0.647). Either LA or arachidonic acid (%) in the whole body of fish increased in a linear patterns (R ² = 0.641 and 0.746, respectively) with increasing dietary LA. Besides, LNA, eicosapentaenoic, acid and docosahexaenoic acid (%) in the whole body increased in a linear pattern (R ² = 0.777, 0.501, and 0.8148, respectively) the increasing dietary LNA level. The present study indicated that LA/LNA ratio less than 13 is recommended for nutrition of tilapia fry.     

Lysine limitation alters the storage pattern of protein,lipid and glycogen in on‐growing Atlantic salmon

This experiment aimed to test the interaction of lysine limitation with nutrient accretion and muscle carnitine depot in Atlantic salmon. Fish were fed adequate or low‐lysine diets for 3 months. Lysine intake was significantly less (48%) in fish fed the low‐lysine diet as compared with that fed the adequate one. There was no difference in dietary amino acids between treatments, with the exception of lysine. The lower lysine intake was reflected in plasma free lysine being 52% less while the free lysine concentration in the liver and muscle were unaffected. Although there was no significant difference between voluntary feed intakes among treatments, fish fed the low‐lysine diet had reduced growth, protein and energy deposition as compared with fish fed the adequate lysine diet. White trunk muscle contained more glycogen and less protein in fish fed the low‐lysine diet while no difference in lipid was observed. The livers from fish fed the low‐lysine diet contained less glycogen and slightly more fat and protein than the livers from fish fed the adequate lysine diet. Lysine limitation reduced carnitine in the liver without affecting muscle carnitine depot. Thus, low‐lysine diets did not likely affect the fatty acid oxidation capacity. This fact was supported by unaffected fatty acid profiles and lipid classes between treatments during the 3‐month study. In conclusion, lysine limitation does not deplete the muscle carnitine depot during the on‐growing seawater phase of Atlantic salmon, but affects the deposition pattern of nutrients.     

Evaluation of dietary chitosan effects on growth performance,immunity, body composition and histopathology of Nile tilapia (Oreochromis niloticus) as well as the resistance to Streptococcus agalactiae infection

The present investigation aimed to evaluate the effect of dietary chitosan supplementation on growth performance, body composition, immune response and histopathology of Nile tilapia, and also the in vitro antibacterial activity of chitosan against Streptococcus agalactiae (S. agalactiae). About 180 fish (average body weight 39.3 ± 0.3 g) were randomly divided into three groups according to chitosan supplementation: control group (basal diet without chitosan), Ch3 group (3 g chitosan/kg diet) and Ch5 group (5 g chitosan/kg diet). Growth performance parameters and body proximate composition were measured before infection but biochemical parameters and lysozyme and antibacterial activities before and after experimental infection. Results of the present investigation showed dietary chitosan (5 g chitosan/kg diet) significantly (p < .05) improved growth performance parameters, body composition (dry matter, crude protein, ether extract, ash, and carbohydrate) and serum biochemistry (total protein, albumin, globulin, with no effect on AST, ALT, urea and creatinine) before infection in Ch5 group than the control. After infection, liver enzymes (serum AST and ALT) were maintained lower in fish fed Ch3 or Ch5 than the control. Serum lysozyme and bactericidal activities significantly increased (p < .05) in chitosan groups before and after the challenge. The mortality rate was markedly reduced in the Ch3 group and prohibited in the Ch5 group after the experimental infection. In conclusion, feeding 3 or 5 g chitosan/kg diet increased the growth rate and improved FCR of Nile tilapia. In addition, it reduced mortality by its antibacterial and immunostimulant effects.     

Zingiber officinale and Glycyrrhiza glabra,individually or in combination,reduce heavy metal accumulation and improve growth performance and immune status in Nile tilapia,Oreochromis niloticus

This study evaluated the impact of dietary ginger and liquorice supplementation on growth performance, physiological and histopathological profiles and heavy metal accumulation in Nile tilapia fingerlings. Fish (n = 1,800, 17.5 ± 0.11 g BW) were randomly distributed into four treatment groups in triplicates and received no supplementation (control group), 5 ml aqueous ginger extract/kg feed (ginger group), 4 ml aqueous liquorice extract/kg feed (liquorice group) or 2.5 ml ginger plus 2 ml liquorice aqueous extracts/kg feed (mix group). The ginger‐liquorice mix supply improved the growth performance and feed efficiency (p < .05), increased the haematocrit and haemoglobin (p < .05), leucocytes (p = .108), neutrophils (p = .054), serum total protein (p < .05), albumin (p = .011) and globulin (p = .094) but decreased (p < .05) the blood urea nitrogen and creatinine than feeding liquorice or ginger lonely compared to the control. Heavy metal loads in pond water induced lamellar telangiectasis of gills and necrosis with sloughing of intestinal villi tips. These detrimental effects were alleviated, and the intestinal villus length (p = .041) and crypt depth (p = .069) were increased with liquorice supply. In all treatment groups, heavy metal contents in fish flesh were lower compared to the control. Thus, using ginger and/or liquorice aqueous extracts can decrease heavy metal accumulation in the fish flesh and exert positive effects on growth performance, metabolic profile and the intestinal and gill morphology of Nile tilapia.     

Dietary nucleotides enhance growth performance,feed efficiency and intestinal functional topography in European Seabass (Dicentrarchus labrax)

Nucleotides, nucleosides and nucleic acids (NU) have many critical functions in supporting life and increasing evidence suggests that exogenous supply can benefit the health of mammals and fish. For these reasons, a 6‐week feeding trial was conducted on juvenile European seabass (Dicentrarchus labrax) with diets containing 0%, 0.15% and 0.3% inclusion of a NU mixture (Laltide^®) derived from the yeast Saccharomyces cerevisiae. At the end of the study no significant differences were found in fish performance, although a tendency towards better performance was indicated in fish fed the Nu0.3 diet. In relation to histological assessment, a significantly greater perimeter ratio; internal to outer (IP/OP) was observed in the posterior intestine of fish fed supplemental NU. Microvilli heights in the posterior intestine were also shown to be significantly promoted in fish fed NU diets (p < 0.05). Goblet cell abundance was shown to be unaffected by the inclusion of NU in the diet (p > 0.05). Overall, this study indicates that orally administered NU may be effective promoters of gut functional topography with marginal associated improvements to fish performance. Nonetheless, longer exposure and/or commercial scale application, and in diets that were challenging in use of high inclusion levels of plant by‐products would potentially amplify improvements in production characteristics, in turn benefiting fish culturists.     

Dietary supplementation with low molecular weight sodium alginate improves growth,haematology, immune reactions and resistance against Aeromonas hydrophila in Clarias gariepinus

A few studies have illustrated the effects of sodium salt derived from alginic acid on different fish species. However, little is known about the effect of sodium alginate on catfish (Clarias gariepinus). Therefore, this study was performed to assess the use of low molecular weight sodium alginate ( LMWSA) in C. gariepinus. A total of 180 apparently healthy C. gariepinus with a mean body weight of 45 g were randomly divided into three equal groups (D1, D2 and D3). D1 the control group received a control diet, while D2 and D3 received 1% and 3% LMWSA, respectively, for 8 weeks. A challenge test against Aeromonas hydrophila was performed on 15 randomly selected catfish for 15 days. At the end of the experiment, catfish in D3 that received a diet of 3% LMWSA showed significant increases in the final body weight, weight gain and thermal‐unit growth coefficient compared with those in D2 and D1. There was a significant decrease in the erythrogram in D1 after the 4‐day pathogen challenge. A leucogram revealed leucocytosis, heterophilia and lymphocytosis in catfish in D2 and D3 compared with those in D1. After the 4‐day challenge, the following changes took place: lysozyme, nitric oxide, phagocytic activity and the respiratory burst were significantly elevated in catfish that received LMWSA and were more pronounced in D3 than in D1. The mortalities of catfish have been stopped after pathogen challenge from 8‐day in D1 and D2 where at 6‐day in D3. Thus, administration of 1% and 3% LMWSA enhances the growth, immune response and resistance of C. gariepinus against A. hydrophila.