A. Couto

Effect of water temperature and dietary starch on growth and metabolic utilization of diets in gilthead sea bream (Sparus aurata) juveniles.

We evaluated the effect of dietary starch level on growth performance, feed utilization, whole-body composition and activity of selected key enzymes of intermediary metabolism in gilthead sea bream juveniles reared at 18 and 25 degrees C. A diet was formulated to contain 48% crude protein, 12% lipids and 30% gelatinized maize starch (diet 30GS). Two other diets were formulated to include the same level of ingredients as diet 30GS except for the gelatinized starch, which was included at 20% (diet 20GS) or 10% (diet 10GS). No adjustment to diet composition was otherwise made. Each diet was fed to triplicate groups of gilthead sea bream (30 g initial mass) for 8 weeks, on a pair-feeding scheme. The higher temperature improved growth performance but the opposite was true for feed efficiency and protein efficiency ratio. Independently of temperature, growth performance, feed efficiency and protein efficiency ratio were lower in fish fed diet 30GS. No effect of temperature or dietary starch level on whole-body composition was noticed. Hepatosomatic index and liver glycogen were higher at 18 degrees C and, within each temperature, in fish fed diet 30GS. Glycemia was not affected by temperature, but was lower in fish fed diet 10GS. Data on enzyme activities showed that increasing water temperature enhances liver glucokinase (GK) and pyruvate kinase (PK) activities, suggesting that gilthead sea bream is more apt to use dietary starch at higher temperatures. No effect of temperature was noticed on hexokinase (HK), fructose-1,6-bisphosphatase (FBPase), glucose-6-phosphate dehydrogenase (G6PD) and glutamate dehydrogenase (GDH) activities. Dietary starch enhanced PK and FBPase activities while depressed GDH activity, suggesting a lack of significant regulation of hepatic glucose utilization and production in this species. HK, GK and G6PD activities were unaffected by dietary composition. Irrespectively of water temperature, gelatinized starch may be included up to 20% in diets for gilthead sea bream juveniles; at higher dietary levels, growth and efficiency of feed utilization are depressed.

Prebiotics effect on immune and hepatic oxidative status and gut morphology of white sea bream (Diplodus sargus)

The aim of this study was to evaluate the effects of short-chain fructooligosaccharides (scFOS), xylooligosaccharides (XOS) and galactooligosaccharides (GOS) on immune and hepatic oxidative status, and gut morphology of white sea bream juveniles. Four diets were formulated: a control diet with fish meal (FM) and plant feedstuffs (PF) (30FM:70PF) and three test diets similar to the control but supplemented with 1% of scFOS, XOS or GOS. Dietary prebiotic incorporation did not affect total blood cell counts, hematocrit, hemoglobin, red blood indices or differential white blood cell counts. Fish fed GOS had lower ACH50 and nitric oxide than fish fed control diet. XOS enhanced immune status through the increase in alternative complement pathway (ACH50), lysozyme and total immunoglobulin. The higher activity of glucose 6-phosphate dehydrogenase in fish fed FOS compared to the other dietary groups was the only related antioxidant enzyme affected by prebiotics in the liver. GOS ameliorated the precocious adverse effects of PF based diet on gut histomorphology, as denoted by the lower incidence of histological alterations in fish fed GOS for 15 days. In conclusion, XOS and GOS at 1% might have potential to be used as prebiotics in white sea bream juveniles.

Temperature and dietary starch level affected protein but not starch digestibility in gilthead sea bream juveniles

A study was carried out with gilthead sea bream juveniles to assess the effect of water temperature (18 and 25°C) and dietary pregelatinized starch level (10, 20 and 30%) on digestibility of protein and starch and on the activity of proteolytic and amylolytic enzymes. ADC of pregelatinized starch was very high (>99%) irrespectively of dietary inclusion level, and it was not affected by water temperature. ADC of protein was also high (>90%) but improved at the higher water temperature. Dietary starch interacted with protein digestibility, which decreased as dietary starch level increased. Temperature affected both acid and basic protease activities, with acid protease activity being higher at 25°C and basic protease activity being higher at 18°C. However, total proteolytic activity and amylase activities were not affected by water temperature. Dietary carbohydrate exerted no effect on proteolytic or amylolitic activities. It is concluded that gilthead sea bream juveniles digest pregelatinized starch very efficiently irrespective of water temperature, due to adjustments of amylase activity to cope with temperature differences. Pregelatinized starch interacts negatively with protein digestibility, with the ADC of protein decreasing as dietary starch levels increase.

Gilthead seabream (Sparus aurata) immune responses are modulated after feeding with purified antinutrients.

The present study aimed to evaluate the effects of two purified antinutrients, soy saponins and phytosterols, in an important species for Mediterranean aquaculture. For this purpose, gilthead seabream (Sparus aurata) were fed six experimental diets containing two levels of those antinutrients, alone or in combination, and a control diet, to apparent visual satiation under controlled conditions. Blood and head-kidney were collected at 7, 15 and 48 days following first feeding in order to assess immune parameters and the expression of immune-related genes. Plasma bactericidal and alternative complement pathway activities increased in fish fed antinutrients compared to fish fed the control diet during the course of the experiment, with more important changes at 7 and 48 days for bactericidal activity and at 7 and 15 days for complement values. In contrast, plasma total immunoglobulins (Ig) increased in fish fed antinutrients only at 48 days. Caspase 1 (casp1), interleukin 18 (il18), colony-stimulating factor-1 receptor (csfr) and hepcidin (hep) presented similar patterns of expression with more important changes at 7 and 48 days, while interleukin 10 (il10) and β-defensin (def) were mainly up-regulated in fish fed antinutrients at 48 days. The level of expression of IgM increased already at 7 days in fish fed the low concentration of both saponins and phytosterols while a general up-regulation was observed at 48 days compared to fish fed the control diet. Results suggest that feeding seabream a diet with purified saponins and phytosterols, alone or in combination, induces a number of changes that are related to the development of inflammation, with most important changes in fish fed the lower phytosterols concentration.

Gut morphology and hepatic oxidative status of European sea bass ( Dicentrarchus labrax ) juveniles fed plant feedstuffs or fishmeal-based diets supplemented with short-chain fructo-oligosaccharides and xylo-oligosaccharides

The effects of short-chain fructo-oligosaccharides (scFOS) and xylo-oligosaccharides (XOS) on gut morphology and hepatic oxidative status were studied in European sea bass juveniles weighing 60 g. Fish were fed diets including fishmeal (FM diets) or plant feedstuffs (PF diets; 30 FM:70 PF) as main protein sources (control diets). Four other diets were formulated similar to the control diets but including 1 % scFOS or 1 % XOS. At the end of the trial, fish fed PF-based diets presented histomorphological alterations in the distal intestine, whereas only transient alterations were observed in the pyloric caeca. Comparatively to fish fed FM-based diets, fish fed PF diets had higher liver lipid peroxidation (LPO), superoxide dismutase (SOD) and catalase (CAT) activities, and lower glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase activities. In fish fed the PF diets, prebiotic supplementation decreased SOD activity and XOS supplementation further decreased CAT activity. In fish fed the FM diets, XOS supplementation promoted a reduction of all antioxidant enzyme activities. Overall, dietary XOS and scFOS supplementation had only minor effects on gut morphology or LPO levels. However, dietary XOS reduced antioxidant enzymatic activity in both PF and FM diets, which indicate a positive effect on reduction of hepatic reactive oxygen species production.

Immersion and distancing during assimilation of problematic experiences in a good-outcome case of emotion-focused therapy

Abstract Objective: Some studies have suggested that a decrease in immersion (egocentric perspective on personal experiences) and an increase in distancing (observer perspective on personal experiences) are associated with the resolution of clinical problems and positive outcome in psychotherapy for depression. To help clarify how this change in perspectives relates to clinical change, the present study compared changes in immersion and distancing across therapy with progress in one client’s assimilation of her problematic experiences. Method: We analyzed all passages referring to the central problematic experience in a good-outcome case of emotion-focused therapy for depression using the Measure of Immersion and Distancing Speech and the Assimilation of Problematic Experiences Scale. Results: Results showed that immersion and distancing were associated with different stages of assimilation. Immersion was associated with stages of emerging awareness and clarification of the problem and in the application of new understandings to daily life. Distancing was associated with problem-solving and attaining insight. Conclusion: The decrease of immersion and increase of distancing associated with therapeutic improvement should not be taken as a recommendation to avoid immersion and encourage distancing. Immersion and distancing may work as coordinated aspects of the processes of psychotherapeutic change.

Humoral and mucosal immune responses in meagre (Argyrosomus regius) juveniles fed diets with varying inclusion levels of carob seed germ meal

ABSTRACT Many studies have assessed the effects of incorporation of plant feedstuffs in fish diets on growth performance, whereas few studies have addressed the effects of fish meal replacement by plant protein sources on fish immune parameters. Thus, the aim of this study was to evaluate the effects on immune response of different inclusion levels of carob seed germ meal (CSGM) as partial replacement for fish meal in diets for meagre (Argyrosomus regius) juveniles. Fish were fed four experimental diets with increased CSGM inclusion levels [0% (control), 7.5% (CSGM7.5), 15% (CSGM15) and 22.5% (CSGM22.5)]. After 1, 2, and 8 weeks of feeding fish were sampled to determine haematological profile and several humoral parameters in plasma and intestine. Results showed that dietary inclusion of CSGM did not negatively affect the immune parameters of meagre. In addition, total numbers of red and white blood cells, as well as thrombocytes, lymphocytes, monocytes, and neutrophils counts were not affected by dietary treatments. All parameters evaluated in plasma were unaffected by dietary CSGM inclusion after 1 and 2 weeks of feeding, with only the haemolytic complement activity showing an increase in fish fed diets with CSGM after 1 week and in fish fed CSGM22.5 diet after 2 weeks. Regarding the innate immune parameters analysed in the intestine, it could be highlighted the increase in alkaline phosphatase and antiprotease activities in fish fed the diet with the higher inclusion of CSGM at 8 weeks. Overall, results suggest that high dietary CSGM inclusion do not compromise immune status or induce an inflammatory response in meagre juveniles. HIGHLIGHTSHaematological profile did not affect by any inclusion levels of CSGM in diets.Minor effects of the experimental diets on humoral immune responses were observed.Haemolytic complement activity in fish plasma was modulated by CSGM diets in all experimental times.Alkaline phosphatase and antiprotease activities were increased in intestine by the CSGM22.5 diet at 8 weeks.Dietary CSGM do not compromise immune status and do not induce an inflammatory response in meagre.