Effects of dietary onion (Allium cepa) powder on growth performance, hemolymph indices and fillet organoleptic properties of juvenile narrow-clawed crayfish, Astacus leptodactylus leptodactylus Eschscholtz, 1823

A 18-week feeding trial was carried out under controlled conditions to compare the effects of onion powder (OP) at six levels (5, 10, 20, 30, 40 and 50 g/kg) on the growth performance, nutritional efficiency indices, hemolymph indices and fillet organoleptic properties of juvenile (5.62 ± 0.39 g) crayfish. The significantly (p < .05) highest values of final weight (71.30 g) and SGR (2.02% per day) and the lowest FCR (1.03) were observed in the juvenile crayfish fed the diet containing 40 g OP/kg. The juvenile crayfish fed the diet containing 40 g OP/kg had the significantly (p < .05) highest THC (105.27 × 105 cell/ml), HC (98.33 × 105 cell/ml), SGC (38.54 × 105 cell/ml) and LGC (49.51 × 105 cell/ml). The crayfish fed the levels of dietary OP higher than 30 g/kg showed the significantly (p < .05) higher values of SOD (4.07–4.30 U/min) and LYZ (6.73–7.20 U/min) compared with those fed 5, 10, 20 and 30 g of dietary OP/kg and control. Polynomial regression of SGR, FCR, PPV and PER suggested that the optimum dietary OP level could be higher than 30 and <50 mg/kg in crayfish reared in culture conditions

Leptin and lipid metabolism in fish

The aim of this chapter is to highlight potential links between leptin and the lipid metabolism in fish, within the context of current research interests of the fish nutrition amd aquaculture sector. In fact, it is envisaged that the whole aquacuture and fish biology sector will significantly benefit from an increased knowledge of such a powerful hormone, and it is believed&nbsp;this will contribute in transforming current aquaculture industry into an environmental and economical means of producing nourishing fish and seafood for the growing global population. The context is framed by a brief introduction on the current challenges in aquaculture and fish nutrition, and susequently the chapter focuses on the potential roles of leptin on voluntary food intake and lipid digestion and absorption in fish. Following this, the possible roles of leptin on lipid deposition and utilisation and the fatty acid metabolism in fish are presented and discussed. Eventually the possible interrelationships between dietary lipids and leptin are analysed underlining how knowledge gained from human nutrition could be extremely useful to tentatively address current constraints and obstacles found in the aquaculture nutrition sector. The present analysis suggests that we are likely only able to see the tip of the iceberg, and great and significant breakthrough discoveries will be likely by fathoming such fascinating area of research

Digestive Enzymes in the Crayfish Cherax albidus: Polymorphism and Partial Characterization

We will deal with the partial characterization and the activity of the following digestive enzymes: amylase, pectinase, alginase, lipase, and protease present in the digestive tract of juvenile freshwater crayfishCherax albidus. Gastric juices, the hepatopancreas, and the intestine were sampled for enzyme analysis. Among carbohydratases, amylase activity was the highest. It was significantly higher in the intestine than in the gastric juice and hepatopancreas. Lipase activity was significantly higher in the hepatopancreas and the intestine compared to the gastric juice. Both alkaline and acid proteases were found. Alkaline proteases were characterized by employing specific protease inhibitors. Both trypsin and chymotrypsin activity was detected. The majority of alkaline protease activity was ascribable to trypsin. Several isoforms of digestive enzymes were identified by gel electrophoresis. This work provides basic information to study the digestive abilities of crayfish

1H‐NMR metabolomic profiling of the crayfish Astacus leptodactylus subjected to polyphenol‐enriched diets

1H-NMR analysis of the hepatopancreas, muscle and haemolymph of Astacus leptodactylus after feeding with polyphenol-enriched diet is reported. 1H-NMR spectra of lipophilic extracts showed the presence of cholesterol, fatty acid residues, phospholipids and triglycerides. 1H-NMR spectra of aqueous extracts identified 35 metabolites in the hepatopancreas, 31 in the muscle and 22 in the haemolymph. A total of 20 metabolites (amino acids and their derivatives) were present in the hepatopancreas, the muscle and the haemolymph. A total of 10 metabolites were present in both the hepatopancreas and the muscle (five amino acids, 2-hydroxybutyrate, choline, myo-inositol, glycogen and uracil). 2-Hydroxyisobutyrate and creatine were present in both the hepatopancreas and the haemolymph. Phosphorylethanolamine, phosphocholine and fumarate were present only in the hepatopancreas and isoleucine only in the muscle. Statistical analysis showed that the percentage of weight gain was statistically higher in polyphenol-enriched diet groups compared to the control and that polyphenols had a stimulating effect on the general metabolism. No stress-related metabolites were higher in crayfish fed with polyphenol-enriched diet. Conversely, phosphatidylcholine, cholesterol and DHA, linked to resistance to environmental stress and diseases, were higher compared to the control diet. This study indicates that 1H-NMR is a useful tool to study the metabolomics in relation to diet differences

Effect of dietary encapsulated organic salts (Na‐acetate, Na‐butyrate, Na‐lactate and Na‐propionate) on growth performance, haemolymph, antioxidant and digestive enzyme activities and gut microbiota of juvenile narrow clawed crayfish, Astacus leptodactylus leptodactylus Eschscholtz, 1823

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Supplementation of dietary apple cider vinegar as an organic acidifier on the growth performance, digestive enzymes and mucosal immunity of green terror (Andinoacara rivulatus)

The present study was designed to investigate the effects of dietary apple cider vinegar (ACV) on digestive enzyme activity and growth performance as well as immune responses and antibacterial activity of skin mucus in green terror (Andinoacara rivulatus). Fish were fed diets supplemented with 0%, 1%, 2% and 4% of ACV (40.830 ppm acetic acid concentration) for 63 days. The final weight and weight gain values were observed to be significantly higher in fish fed with 2% of ACV compared to the control group (p .05). ACV treatment resulted in a significant increase in the intestinal protease, α‐amylase, lipase and alkaline phosphatase activities compared to control (p < .05). The activities of digestive enzymes in fish fed with 2% and 4% of ACV diets were significantly higher than the other groups (p < .05). The total protein content, alternative haemolytic complement, alkaline phosphatase, total immunoglobulins and lysozyme activities of skin mucus increased significantly in fish fed with ACV diets (p < .05). In conclusion, administration of ACV enhanced digestive enzyme activity, growth performance, immune responses and the immune properties of skin mucus, and it can be used as a natural growth promoter and immunostimulant in green terror culture

The effects of dietary nucleotide content on the growth performance, digestibility and immune responses of juvenile narrow clawed crayfish, Astacus leptodactylus leptodactylus Eschscholtz, 1823

A 126-day experiment was carried out under controlled conditions to compare the effects of five levels (0.5, 1.0, 1.5, 2.0 and 2.5 g kg � 1 ) of dietar

Development of Biopolymers as Binders for Feed for Farmed Aquatic Organisms

Feed for farmed aquatic organisms should guarantee reasonable degree of stability in aquatic medium, long enough for organisms to consume it. Indeed, there is a general complaint about the loss of nutritional and attractive properties upon exposure of a diet to water. Natural substances able to generate firm pellet feed are therefore highly sought. Such binders should improve the stability of feed, be low cost, and hopefully make and extra source of energy. Biopolymers, have properties that make them suitable for use as aquatic feed binders. Some biopolymers are derived from biomass, biodegradable and renewable. The purpose of this chapter is therefore to review recent reports and progress surrounding the possible employment of sustainable biopolymers as binders for feed for farmed aquatic organisms

Influence of Extraction Techniques on Physicalchemical Characteristics and Volatile Compounds of Extra Virgin Olive Oil

The purpose of this study was to investigate three types of extraction methods of extra virgin olive oil (EVOO) from the same cultivar (Ortice olive cultivar): traditional or pressing (T) system, decanter centrifugation (DC) system and a patented horizontal axis decanter centrifugation (HADC) system. Oil samples were subjected to chemical analyses: free acidity, peroxide value, ultraviolet light absorption K232 and K270, total polyphenols, antioxidant capacity, volatile compounds and olfactory characteristics by electronic nose. The two centrifugation systems showed better free acidity and peroxides value but total polyphenol content was particularly high in extra virgin olive oil produced by patented HADC system. Same volatile substances that positively characterize the oil aroma were found in higher amount in the two centrifugation systems, although some differences have been detected between DC and HADC system, other were found in higher amount in extra virgin olive oil produced by T system. The electronic nose analysis confirmed these results, principal component analysis (PCA) and correlation matrix showed the major differences between EVOO produced by T and HADC system. Taken together the results showed that DC and HADC systems produce EVOO with better characteristics than T system and patented HADC is the best extraction system

Influence of polyphenols from olive mill wastewater on the gastrointestinal tract, alveolar macrophages and blood leukocytes of pigs

In the last years, great importance has been given to the beneficial effects of polyphenols. Among the most relevant health promoting effects, there is the capacity to reduce the amount of free radicals and stimulate the immune response. In this study, polyphenols extracted from olive mill wastewater (OMWW), were fed to adult 'Casertana' pigs during the finishing period. No significant differences in the length of the jejunum-ileum villi and the depth of the colon crypts were detected between control and polyphenols fed pigs. Instead, intra-epithelial and lamina propria leukocytes were more abundant in pigs fed polyphenols (p < .05). Cyclooxygenase-2 immunoreactivity in the gastrointestinal tract, employed as marker of inflammation, was more intense in the control group. Superoxide anion production in primary cell cultures of both blood leukocytes and alveolar macrophages was lower in pigs fed polyphenols (p < .05). Taken together these data indicate that, according to our in vitro studies, OMWW polyphenols seem to be potent antioxidants, while the interpretation of the in vivo experiments is more problematic and further studies are necessary on the interactions between bioactive feed compounds and intestinal status. Such studies can contribute to a better understanding of both positive and negative interactions in vivo and to the identification of new functional feeds.HIGHLIGHTS The effects of polyphenols extracted from olive mill wastewater (OMWW) have been studied in pigs. Gut morphology, inflammation and immune response were investigated. OMWW polyphenols act as potent antioxidants