From freshwater to marine aquaponic: new opportunities for marine fish species production

Due to the increasing world population, by 2050 food production should be increased of about 70% to 100%. Tanks to the lowest “carbon footprint”, aquaculture seems to be the most sustainable system for producing food (protein) of animal origin. Despite that, progress can be done for further improving aquaculture sustainability through the “aquaponic” system (IAS). A IAS is based on the bacteria nitrogen cycle which convert fish waste (faeces and uneaten feed) into nitrite and nitrate, this latter absorbed by plants grown in the hydroponic section of the aquaponic system; as a results, water is “depurated” and recycled into the fish tanks. Advantages of this system are the high productivity, the reduced water requirement, the neglectable waste production, the reduced plant disease incidence and pesticides utilization, the modularity of the system which allow its uses for a wide range of purposes (urban agriculture, people resilience in developing countries, marginal land exploitation, etc.); for a contrary, disadvantages are the relevant initial investments, the required high education level of the employees, the “sensitivity” of the systems and some minor others. A relevant future challenge for scientists is to develop “marine aquaponic system” for producing more valuable fish and crops, interesting also for the EU and ‘developed countries’ market

Beta glucan enhances the wound healing process in zebrafish

β-glucans are natural compounds that interact with the innate immune system. Macrophages play an important role in wound healing process and appear to act as the key regulatory cells for skin repair by removing dead tissues and killing pathogens. Macrophages also produce growth factors that stimulate cells involved in wound healing (production of extracellular matrix). Discovering natural products which may enhance the wound healing process in fish, has numerous health benefits and 1,3-1,6 ß-glucans may reduce the negative effect of stress, inflammatory reactions, and secondary infections. In this study, the effects on wound healing process in zebrafish (Danio rerio) of 1,3-1,6 ß-glucan extracted from yeast cell wall was investigated. Ninety female fish were distributed into 3 groups (3 replicates). Two products were used as source of 1,3-1,6 ß-glucan: MacroGard® and new MacroGard (Biorigin©), MI and MII respectively; fish daily feed intake was estimated in advance (3.88% BW) and both MI and MII included into the feed for reaching the dose of 12.5 mg kg-1 BW. Treatments started 2 weeks before injuring. Afterwards, two circular shape wounds were made using a laser source on the dorsal edge of the abdomen. Wounds were then digitally photographed at 2, 4, 10, 16, 20, 30 days post wound (dpw). Wound area was measured by Image J® software and wound size given as a mean of the two wounds for each fish. The first clear differences of wound sizes (1.882, 1.725 and 1.665 mm2, for Control, MI and MII, respectively) were observed already at 4 dpw and differences were statistically significant between MI and MII compared to Control group (P<0.05); this early effect seems to suggest a rapid influx of immune cells to a wound in particular when "activated" by 1,3-1,6 ß-glucan (Paul and Fend 2009). Again, at 16 dpw groups MI (0.766 mm2) and MII (0.634 mm2) showed significantly (P<0.05) lower wound area than Control (0.994 mm2); at 20 dpw, wound area of MII (0.518 mm2) was significantly (P<0.05) different from Control (0.702 mm2) and MI (0.713 mm2). Analysis of final wound status (at 30 dpw) showed that 67.9% of fish from MII group had completely healed wounds while that was significantly (P<0.05) lower with 23.1% and 41.4% in control and MI groups, respectively suggesting that MII has better wound healing potential than MI. The present study demonstrate that 1,3-1,6 ß-glucan (MacroGard®) have potential to be applied as natural wound healing agent in fish. Particularly interesting seems mainly to be their early effect that may imply a higher protection from possible secondary infections. However, further studies are required to determine the optimal feed inclusion in diets for different fish species as well as to explain the slightly higher wound healing effects observed for MII than MI

Pheasant (Phasianus colchicus) hens of different origin. Dispersion and habitat use after release

Because of the importance of pheasants as a game bird species in many European Countries, information on the success of the restocking programs is interesting for evaluation. For this reason the survival, behaviour and habitat selection of 10 wild translocated and 20 released ring-necked pheasants (10 offspring of wild captured and 10 from the farmed strain, both farm-reared) was studied using radio-telemetry during March-August (fixes were grouped in 3 categorized periods: March 2 - April 18; April 19 - May 28; May 29 - August 16). All the captive reared pheasants were reared according to the new disciplinary rules set forth by the Toscana region for the production of pheasants destined to be released in the wild as part of a game repopulation program. The study was carried out in a hilly area of the Tuscany characterised by 18.1% woodland (core: 1654895E, 4850468N). Results showed that live weights were higher in the farm-reared pheasants (either directly captured or offspring of the captured, P<0.05). The tarsus length statistically differed between the farmed offspring of the captured pheasants and the farm strain (P<0.05). The survival rates and breeding success of the surviving subjects were very high and did not differ between groups (survival rates: 50.0%, 70.0% and 80.0%, and breeding success: 60.0%, 28.6% and 50.0%, for the captive-reared offspring of captured wild pheasants, the captive-reared farm pheasants and the captured wild pheasants, respectively). The dispersion increased with time in the wild translocated pheasants (576 m, 889 m and 1209 m) while the offspring of the captured wild pheasants and the farm strain remained in the vicinity of the releasing site. The wild pheasants showed an increasing distance from the country houses, contrary to the offspring of captured wild pheasants and the farm strain. Artificial feeding stations were better used by the farmreared pheasants, which remained in the vicinity of the artificial feeding points. The results of our study showed that pheasants, reared according to the disciplinary rules stated for the production of pheasants for wildlife reproduction programs, although more expensive, can guarantee the genetic identity with the resident populations and are able to provide good survival rates and breeding success of the released pheasants, of course when restocking is carried out in areas suitable for pheasant wildlife

EFFECTS OF 1,3-1,6 ß-GLUCAN FEED INCLUSION ON CAUDAL FIN REGENERATION PERFORMANCES OF ZEBRAFISH Danio rerio

Zebrafish (Danio rerio) are considered an interesting animal model for studying the tissue regeneration mechanisms because able to regrow amputated fins. Neutrophils and macrophages have shown functionally important role in tissue repair. Macrophages appear to act as the key regulatory cells for skin repair by removing dead tissues and killing pathogens. Macrophages also produce growth factors that stimulate other cells involved in wound healing. Since β-glucans may "activate" immune cells and macrophages in particular, our hypothesis is that they may positively affect the tissue regeneration process. For these reasons, we investigated the effect 1,3-1,6 β-glucan (extract form yeast cell wall) on caudal fin regeneration in zebrafish. Ninety fish were distributed into 3 groups (3 replicates). Two products were used as source of 1,3-1,6 ß-glucan: MacroGard® and new MacroGard (Biorigin©), MI and MII, respectively. Fish daily feed intake was estimated in advance (3.75% BW) and both MI and MII included into the feed for reaching the dose of 12.5 mg kg-1 BW. Feeding treatment with MI and MII was started just after amputation. The fin regeneration process was observed and described by measuring the fin regenerated area (RA=(x dpa fin area/pre-amputation fin area)*100) and calculating the daily regenerated area (DRA=(x dpa fin area-x+1 dpa fin area)/pre-amputation fin area)*100). The fin regeneration process is also described by a quadratic equation. MacroGard® showed a significantly (P0.05) were observed between the two experimental groups. Further studies are necessary for understanding the mode of action of 1,3-1,6 ß-glucan on fin regeneration

Application of a smart dynamic scale for measuring live-fish biomass in aquaculture

— The need of measuring the fish biomass, either for in-land facilities or offshore cages, drove recently to develop a cheap dynamic scale (by MEGA Materials srl), based on a board of the Arduino family, suitable to measure live-fish weights. Via a Bluetooth transmitter and a specific app the communication with smartphones is allowed. The estimation of live-fish biomass is extremely relevant to precisely quantify the daily dose of feed to be supplied and to avoid a reduction of fish growth. We present the comparison between ‘static’ and ‘dynamic’ weight measures of seabream juveniles reared in tanks

Quantification of noradrenergic-, dopaminergic-, and tectal-neurons during aging in the short-lived killifish Nothobranchius furzeri

Parkinson's disease (PD) is characterized by phosphorylation and aggregation of the protein alpha-Synuclein and ensuing neuronal death progressing from the noradrenergic locus coeruleus to midbrain dopaminergic neurons. In 2019, Matsui and colleagues reported a spontaneous age-dependent degeneration of dopaminergic neurons and an even greater neurodegeneration of the noradrenergic neurons in the short-lived killifish Nothobranchius furzeri. Given the great possible relevance of a spontaneous model for PD, we assessed neurodegeneration of noradrenergic and dopaminergic neurons in two further laboratory strains of N. furzeri. We implemented, for the first time in N. furzeri, a whole-brain clarification technique and proceeded to entire 3D nuclei reconstruction to quantify total cell numbers in two different stains of N. furzeri. In both strains, we observed that age-dependent neurodegeneration is limited to the locus coeruleus and does not involve the posterior tuberculum. We also applied 3D counting to the optic tectum, an area of active adult neurogenesis, and detected an increase of neurons with age. Our results confirm age-dependent neurodegeneration of noradrenergic neurons, a condition reminiscent of the presymptomatic stage of PD indicating that N. furzeri could be used in the future to identify modifying factors for age-dependent neurodegeneration and open the intriguing possibility that natural genetic variation may influence the susceptibility of dopaminergic neurons

Utjecaj dijetalnog ribljeg ulja na razinu n-3 polinezasićenih masnih kiselina, trans-kiselina i konjugirane linolne kiseline u ovčjem mlijeku

Three groups of ten lactating Sardinian ewes were used between 3rd and 6th month of lactation to determine the effects of supplementing diets with n-3 fatty acids on milk production and milk fat composition. The control group (A) was fed on a mixture of Gramineae hay with a pelleted alfalfa and concentrate; the other groups (B and C) were given the control ration supplemented with graded levels of fish oil. Milk content of nutritionally important fatty acids (n-3 polyunsaturated fatty acids, PUFA; trans acids and conjugated linoleic acid, CLA) was determined by gas chromatography. Unlike cow milk, milk of normally fed ewes contained detectable quantities of n-3 PUFA and higher amounts of CLA. The supplementation with fish oil resulted in an increased milk fat levels of n-3 PUFA, CLA and trans isomers. There was a positive correlation (R2 = 0.964) between the trans and n-3 fatty acid content in ewe milk, and a close positive correlation (R2 = 0.996) between CLA and trans monoenoic fatty acid contents. PUFA supplementation resulted in a slightly, but not statistically significative, decrease of milk fat percentage. On the contrary, dietary fish oil markedly affected milk production: ewes fed on the n-3 supplemented diet produced more milk than the ewes fed with the control diet.Izdvojene su tri skupine od po 10 ovaca sa Sardinije između 3. i 6. mjeseca laktacije kako bi se utvrdio utjecaj dodatne ishrane s n-3 masnim kiselinama na proizvodnju mlijeka i sastav masnoća u mlijeku. Kontrolna skupina (A) hranjena je smjesom sijena od Gramineae s kuglicama lucerne i koncentratom; ostale skupine (B i C) hranjene su kao i kontrolna, ali uz sve veću količinu ribljeg ulja. Plinskom kromatografijom određene su u mlijeku nutritivno važne masne kiseline (n-3 polinezasićene masne kiseline, PUFA; trans-kiseline i konjugirana linolna kiselina, CLA). Za razliku od kravljeg mlijeka, mlijeko normalno hranjenih ovaca sadržavalo je primjetne udjele n-3 PUFA i veće količine CLA. Dodatak ribljeg ulja očitovao se u povećanoj količini n-3 PUFA, CLA i trans-izomera u mliječnoj masti. U ovčjem mlijeku postoji pozitivna korelacija (R2 = 0,964) između količine trans- i n-3 masnih kiselina, a uska pozitivna korelacija (R2 = 0,996) između udjela CLA i trans-monoenskih masnih kiselina. Dodatak PUFA uzrokovao je slabo, ali statistički nesignifikantno, snizivanje postotka mliječne masti. Dijetalno riblje ulje značajno je utjecalo na proizvodnju mlijeka: ovce hranjene dodatnim n-3 masnim kiselinama proizvele su više mlijeka od onih koje su bile u kontrolnoj skupini

Social Preference Tests in Zebrafish: A Systematic Review

The use of animal models in biology research continues to be necessary for the development of new technologies and medicines, and therefore crucial for enhancing human and animal health. In this context, the need to ensure the compliance of research with the principles Replacement, Reduction and Refinement (the 3 Rs), which underpin the ethical and human approach to husbandry and experimental design, has become a central issue. The zebrafish (Danio rerio) is becoming a widely used model in the field of behavioral neuroscience. In particular, studying zebrafish social preference, by observing how an individual fish interacts with conspecifics, may offer insights into several neuropsychiatric and neurodevelopmental disorders. The main aim of this review is to summarize principal factors affecting zebrafish behavior during social preference tests. We identified three categories of social research using zebrafish: studies carried out in untreated wild-type zebrafish, in pharmacologically treated wild-type zebrafish, and in genetically engineered fish. We suggest guidelines for standardizing social preference testing in the zebrafish model. The main advances gleaned from zebrafish social behavior testing are discussed, together with the relevance of this method to scientific research, including the study of behavioral disorders in humans. The authors stress the importance of adopting an ethical approach that considers the welfare of animals involved in experimental procedures. Ensuring a high standard of animal welfare is not only good for the animals, but also enhances the quality of our science

Effects of dietary yeast beta-1,3-1,6-glucan on growth performance, intestinal morphology and chosen immunity parameters changes in Haidong chicks

Objective: This study investigated the effects of 1,3-1,6 beta-glucan added to the diet of Haidong chicks reared under hypoxic conditions, to ascertain the growth performances, immunity and intestinal morphology changes. Methods: A total of 750 chicks were divided into five groups and fed diets containing 0.5g/kg, 1.0g/kg and 2.0g/kg 1,3-1,6 beta-glucan from yeast (G1, G2, G3, respectively), 0.2g/kg Taylor rhizomorph (T) and a control feed (C). Results: The body weight and body weight gain was higher in chicks fed 1,3-1,6 beta-glucan and Taylor rhizomorph than in control group. Feed conversion ratio significantly differed for G2 and G3 groups in comparison to control group. The relative weight of bursa was higher in G1, G2 and G3 groups. The white blood cells and lymphocytes were significantly increased in groups fed 1,3-1,6 beta-glucan. The IgG of serum peak appeared in the G3 group. The villous height of the duodenum was higher in 1,3-1,6 beta-glucan feed groups. In the jejunum, the villous height was higher in G2 and G3 groups and crypt depth for all the groups fed β-glucan. At ileum level the villous height and crept depth was higher for groups G1, G2 and G3. Conclusion: The growth performance of Haidong chicks is improved when 10 and 20 g/kg 1,3-1,6 beta-glucan is included in the diet; hence, it is suggested to diet include 1,3-1,6 beta-glucan in poultry diet to reduce and replace the use of antibiotics

Selenium and vitamin E diet inclusion for optimal reproduction performances of red-legged partridge (Alectoris rufa)

To date there is little knowledge regarding the requirements of Se and vitamin E of red-legged partridges (Alectoris rufa). For this reason, in the present study four different Se and vitamin E diet inclusions have been tested. A total of 360 parents were used and randomly divided into four groups; diets were supplemented with 0.2, 0.3, 0.4 and 0.5mg/kg of Se and Se to vitamin E ratio was kept approximately constant in all groups. The effects of the diets on parents’ reproduction performances and on embryos visceral organs were investigated. The best laying rate was reached with 0.4mg/kg Se diet supplementation while the best hatching rate was reached with 0.3mg/kg (p&lt;0.05). The relative weight of duodenum, jejunum and ileum in embryo was higher (p&lt;0.05) in the groups fed 0.4 and 0.5 mg/kg Se compared to the other groups. Significant differences (p&lt;0.05) were also observed for jejunum and ileum length as animals were fed the highest Se to vitamin E ratios. The number and height of villi and goblet cells density of jejunum were higher (p&lt;0.05) in the groups fed 0.4 and 0.5 mg/kg of Se than in the group fed 0.2 mg/ kg. Epithelial buds density in the Bursa of Fabricius of embryos was significantly higher (p&lt;0.05) for 0.4 and 0.5mg/kg Se supplemented groups than in the others. In conclusion our results suggest that 0.4 mg/kg of selenium and 100 mg/kg vitamin E should be included in the parents’ diet in order to optimise red-legged partridges performances