Uticaj hrane sa različitim udelom masnih kiselina na stresne reakcije kod šarana (preliminarni rezultati)

Riblje brašno i riblje ulje su važne komponente riblje hrane koja se koristi u akvakulturi. Oni sadrže nezasićene masne kiseline koje su važne kako u ishrani riba tako i u ishrani ljudi. Međutim, izvori ribljeg brašna i ulja su ograničeni. Cilj AQUAMAX projekta, koga finansira EU, je da se riblje brašno i ulje zamene ili dopune sa biljnim uljima. Tim za imunologiju u Institutu za ribarstvo, akvakulturu i irigaciju ispitivao je efekat dve različite hrane za ribe (hrana dostupna na tržištu i hrana sa dodatkom Camelina ulja) na pojavu stresa izazvanog ograničenim prostorom kod šarana. Na bazi rezultata ovog istraživanja može se zaključiti da primenjena ishrana nema uticaja na toleranciju šarana na stres izazvan ograničenim prostorom

Solid state treatment with Lactobacillus paracasei subsp. paracasei BGHN14 and Lactobacillus rhamnosus BGT10 improves nutrient bioavailability in granular fish feed

The aim of this research was to improve nutritive value of fishmeal-based feed by lactobacilli in order to achieve satisfactory nutrient availability needed to support fish development. Feed was solid-state treated at a laboratory scale with the combination of Lactobacillus paracaseisubsp. paracasei BGHN14 and Lactobacillus rhamnosus BGT10 in different experimental settings, which included the variation of strain ratio, total lactobacilli concentration, percentage of moisture and duration of incubation. Short peptides, soluble proteins, phospho-, neutral and unsaturated lipids were quantified. Differences among treated and control feeds were evaluated by Student t-test, while Gaussian process regression (GPR) modeling was employed to simulate the incubation process and define the optimal treatment combination in the context of overall feed nutritional profile. Treatment duration was shown to be the critical determinant of final outcome, either as single factor or via interaction with strain ratio. Optimal nutrient balance was achieved with 12 h incubation period, 260% moisture, 75:25 and 50:50 BGHN14:BGT10 ratios and 200 mg of lactobacilli per g of dry feed. This study should serve as the basis for large-scale tests which would simulate on-farm production of both fishmeal-based and unconventional, lower cost aquafeed with added value

Immune responses of resistant and sensitive common carp families following experimental challenge with Aeromonas hydrophila

Parameters of non-specific immune response and level of specific and natural antibodies were investigated after an experimental challenge with Aeromonas hydrophila in genetically different common carp (Cyprinus carpio) families. Ten resistant and ten sensitive families were used for the experiment, which had been selected out of 96 families, based on the results of a preliminary challenge test. Blood samples were collected 12 h, one week and 21 days following the challenge. Phagocytic and respiratory burst activities of phagocytic cells, lysozyme activity of the blood plasma were determined. Level of specific antibodies against A. hydrophila and level of natural antibodies were measured in the samples taken on the 28th day. Non-infected fish from resistant and sensitive families were used as controls. Significant differences of phagocytic and lysozyme activities were measured between the challenged resistant and sensitive families. The level of specific antibodies between the same families was also found to be significantly different. There were no significant differences of the studied parameters between the control groups. Based on our results, phagocytic activity of leukocytes, plasma lysozyme activity and specific antibody titre were found to be higher in the resistant families than in the sensitive ones following infection with A. hydrophila

Uticaj hrane sa različitim udelom masnih kiselina na stresne reakcije kod šarana (preliminarni rezultati)

Riblje brašno i riblje ulje su važne komponente riblje hrane koja se koristi u akvakulturi. Oni sadrže nezasićene masne kiseline koje su važne kako u ishrani riba tako i u ishrani ljudi. Međutim, izvori ribljeg brašna i ulja su ograničeni. Cilj AQUAMAX projekta, koga finansira EU, je da se riblje brašno i ulje zamene ili dopune sa biljnim uljima. Tim za imunologiju u Institutu za ribarstvo, akvakulturu i irigaciju ispitivao je efekat dve različite hrane za ribe (hrana dostupna na tržištu i hrana sa dodatkom Camelina ulja) na pojavu stresa izazvanog ograničenim prostorom kod šarana. Na bazi rezultata ovog istraživanja može se zaključiti da primenjena ishrana nema uticaja na toleranciju šarana na stres izazvan ograničenim prostorom

Supplementation of lactobacilli improves growth, regulates microbiota composition and suppresses skeletal anomalies in juvenile pike-perch (Sander lucioperca) reared in recirculating aquaculture system (RAS): A pilot study

This research aimed to test the effects of lactobacilli, applied to cultured pike-perch, either through hydrolyzed OTOHIME fish diet, or through Artemia nauplii, on fish growth, microbiota balance and skeletal development. On the 12th Day Post Hatching (DPH) fish were divided into following treatment groups: two groups received the combination of OTOHIME and nauplii enriched either with Lactobacillus paracasei BGHN14 + Lactobacillus rhamnosus BGTH or with Lactobacillus reuteri BGGO6-55 + Lactobacillus salivarius BGHO1, and one group received OTOHIME hydrolyzed by BGHN14 + BGT10 and non-enriched nauplii. Control group received non-enriched nauplii and non-hydrolyzed OTOHIME. The treatment lasted 14 days and fish were sacrificed on the 26th DPH for the assessment of digestive enzyme activity and microbiota composition. Individual total lengths and individual body weights were recorded at the end of the treatments, on the 26th DPH, and also on the 45th DPH, in parallel with the evaluation of skeletal deformities and fish survival. Our results indicated positive effect of Anemia enriched with BGGO6-55 + BGHO1 on fish growth, skeletal development and trypsin to chymotrypsin activity ratio (T/C), as an indicator of protein digestibility. Hydrolysis of OTOHIME was also associated with better skeletal development, higher T/C values and lower levels of Aeromonas and Mycobacterium spp., which are important fish pathogens. Though additional testing in larger cohort studies is needed, these observations are promising in terms of usage of probiotics for improved environmentally friendly production of pike-perch in Recirculating Aquaculture System (RAS)

Production and efficacy of an Aeromonas hydrophila recombinant S-layer protein vaccine for fish

A recombinant protein for the S-layer protein of Aeromonas hydrophila was produced and its ability to protect common carp Cyprinus carpio L. against six virulent isolates of A. hydrophila was assessed. A group of 120 carp (30-40 g) were vaccinated intra-peritoneally with 0.1 ml of adjuvanted vaccine (30 μg protein per fish). Another group of 120 carp were injected with 0.1 ml of PBS-adjuvant mixture to serve as controls. Twenty fish from each group were challenged with each one of six virulent isolates of A. hydrophila 35 days post-vaccination. The fish were maintained in 12 separate tanks before terminating the experiment at 16 days post-challenge. The relative percentage survival (RPS) for the six isolates of A. hydrophila ranged from 56 to 87%. The difference in survival rate of fish challenged with four of the isolates was statistically significant in vaccinated fish compared to control fish, when analysed using a Chi-square test. The results of the study suggest that the recombinant S-layer protein of A. hydrophila could be useful as a vaccine antigen to protect fish against different isolates of this pathogenic bacterium

The effect of live and inert feed treatment with lactobacilli on weaning success in intensively reared pike-perch larvae

Weaning to inert diet in intensively reared pike-perch larvae is confronted with significant fish loss, which prevents successful commercialization of pike-perch production. Achievement of satisfactory feed quality and effective assimilation of nutrients by larval fish is the major challenge in larval production process. Aim of this study was to evaluate whether treatment of live and inert feed with lactobacilli could alleviate growth retardation associated with early weaning of pike-perch reared in recirculating system. Weaning started on 18th day post-hatching (DPH) either as sudden weaning (SW) or by co-administration of Anemia for six days (gradual weaning, GW). Prior to administration to fish, Anemia was treated with Lactobacillus salivarius BGHO1/Lb. reuteri BGGO6-55, while inert feed was treated with Lb. paracasei subsp. paracasei BGHN14/Lb. rhamnosus BGT10. Treatment with lactobacilli slightly raised neutral lipid level in Anemia nauplii, but significantly reduced their content in dry feed. Fish were sampled on the 24th DPH. Survival, morphometric indices, skeleton differentiation, digestive enzyme activity and opportunistic pathogenic bacteria level were assessed in whole fish specimens. GW fish were presented with better survival, body growth and phospholipase A2 (PLA2) activity. Alongside, Vibrio spp. growth was suppressed in these fish and skeleton development was improved, according to Alizarin Red staining and ColIA1/Sparc mRNA expression data. Lactobacilli application in GW fish correlated with an increase of survival, condition factor and growth rate, according to trypsin and chymotrypsin activities, indicating better utilization of dietary proteins for muscle building. In SW fish, lactobacilli elevated chymotrypsin activity, PLA2 to lipase activity ratio and improved survival and ossification, as evident from Alizarin Red staining and ColIA1/Sparc mRNA expression. This indicated improved fatty acid absorption and control of metamorphosis process. Furthermore, lactobacilli suppressed Vibrio spp. growth in SW fish. Aside from demonstrating the ability of lactobacilli to aid weaning in pike-perch larvae, this study indicated that different types of food treatment may direct fish growth in a predictable manner, allowing further cost-effective improvements of larval pike-perch rearing in intensive system

Lactobacillus salivarius BGHO1 and Lactobacillus reuteri BGGO6-55 modify nutritive profile of Artemia franciscana nauplii in a strain ratio, dose and application timing-dependent manner

This study aimed to analyze an impact of Lactobacillus salivarius BGHO1 and Lactobacillus reuteri BGGO6-55 supplemented to Anemia franciscana cultivation medium on biochemical profile of hatched nauplii. Impacts of different BGHO1:BGGO6-55 ratios (75:25, 50:50 and 25:75) and their total concentrations (250 and 500 g/kg of Anemia cysts) at different timings of bacteria application (pre- and post-hatching) were examined. The effects were evaluated by quantification of naupliar peptide, soluble protein, phospho-, neutral and unsaturated lipid content. Uni and multifactorial analysis of variance (ANOVA) were used to estimate the effects of treatments relative to control and to model factor interactions, respectively Statistical analysis indicated that posthatching application of 75:25 strain ratio at high dose was associated with an increase of neutral lipid amount. Furthermore, factor interaction profiling identified positive correlation of lacto-bacilli concentration with the level of free amino acids/short peptides, phospho-, neutral and unsaturated lipids, but only at 50:50 strain ratio combination. Application of lower lactobacilli dose at 75:25 strain ratio caused an increase of soluble protein and phospholipid amount. Hypothetically, graded response of Artemia nauplii to lactobacilli supplementation was induced with different BGHO1 doses. It assumedly ranged from stress-response protein synthesis at lower doses to membrane permeability alterations and triglyceride-mediated defense mechanism activation at higher BGHO1 doses. In contrast to lactobacilli supplementation after Anemia hatching, pre-hatching application of lactobacilli was not associated with an increase of Anemia nutritive profile, though again there was a positive association of lactobacilli concentration with nutrient amount. This implicates interference of lactobacilli with the hatching process. Results presented here facilitate the design of future studies aiming to modify Artemia nutritive profile in accordance with nutritional demands of cultivated fish species