Protein Level and Efficiency of Feed Mixture for Common Carp (Cyprinus Carpio)

The quality of fish feed and its nutritional value are important for fish production. From an economic point of view it is vital to ensure a cheaper final product while from the nutritional aspects it is essential to fulfill the requirements of fish. The aim of this study was to investigate the digestibility and effect of feed mixtures with different protein content on growth of carp fry. The experiment was carried out at the Laboratory for fish nutrition of the Faculty of Agriculture, University of Belgrade, for 90 days. Fish were fed with concentrate mixtures having 38% (A), 41% (B) and 44% (C) of proteins. The bigger share of the protein part in A were plant proteins (PP), in C fish meal (FM), while in B the share of FM and PP was approximately the same. Results showed significant differences between digestibility of different feed mixture. The digestibility of protein and fat were higher in fish fed diets with higher protein content. Digestibility of nitrogen-free extracts (NFE), energy and digestible energy was not statistically significant (p> 0.05) regardless of the level of protein in the diet. The results indicate that the increase in the digestibility of proteins is in accordance with the increase in protein content in the diet e.g. diets with higher content of FM

Uticaj količina hrane na prirast šaranske mlađi u tankovima

Šaran se gaji u sva tri sistema: ekstenzivni, poluintenzivni i intenzivni. Za razliku od ekstenzivnog gde je prirast ribe isključivo zavistan od prirodne hrane, poluintenzivni i intenzivan sistem gajenja riba su bazirani na delimičnoj, odnosno potpunoj zavisnosti od dodatne hrane. Kako tokom sezone gajenja, prirodna hrana u ribnjacima sa poluintenzivnim sistemom ima veoma izražen sezonalni karakter, u periodu sa optimalnim temperaturama za rast šarana (od sredine juna pa do kraja avgusta) prirast je u najvećoj meri zavistan od vrste i količine dodatne hrane. Sa ekonomskog, ali i ekološkog aspekta važno je obezbediti hranu koja će rezultirati niskim koeficijentom konverzije, visokim tempom rasta, dobrim zdravstvenim stanjem gajenih riba, visokim kvalitetom finalnog proizvoda, tj. ribljeg mesa i što manjim opterećenjem vodene sredine organskim materijama, fosforom i azotom. Od velike važnosti je i obezbeđivanje adekvatne količine dodatne hrane, odnosno ne dozvoliti da količina hrane bude manja od potreba gajene ribe, ali i ne preterati sa količinom koja od strane riba neće biti racionaln iskorišćena i time smanjiti profitabilnost gajenja riba. U cilju određivanja optimalnog procenta hrane u odnosu na ihtiomasu gajene mlađi šarana urađen je ovaj rad. Eksperiment je realizovan u Centru za ribarstvo i primenjenu hidrobiologiju, Poljoprivrednog fakulteta, Univerziteta u Beogradu tokom 90 dana. Za prihranu šaranske mlađi korišćena je ekstrudirana hrana sa 38% proteina i 8% masti proizvođača Vetrinarski zavod «Subotica», veličine peleta 2 mm. Eksperiment je realizovan u 4 tretmana sa po 3 ponavljanja. Tretmani su se razlikovali po procentualnom učešću količine hrane u odnosu na ihtiomasu u tanku na početku svakog tridesetodnevnog perioda. U prvom tretmanu je dnevni obrok riba 2%, u drugom 3%, u trećem 4%, dok su ribe u tretmanu četiri hranjene sa 5% hrane u odnosu na ihtiomasu. U svaki od 12 nezavisnih tankova nakon perioda adaptacije, nasađeno je po 40 jedinki šarana, prosečne mase 6,41 do 6,47 g. Hranjenje riba je obavljano svakodnevno upotrebom hranilica sa trakom. Na osnovu prosečnih masa riba po periodima i na kraju eksperimenta, statističkom analizom je ustanovljeno da postoje vrlo značajne razlike u prirastu u zavisnosti od dnevnog obroka. Ribe hranjene sa 5% hrane u odnosu na ihtiomasu ostvarivale su statistički značajno veći prirast u odnosu na ribe hranjene sa 2, 3 i 4% hrane. Korišćenjem ovog rezultata se otklanja dilema koja je količina hrane za prihranu gajene šaranske mlađi optimalna tokom gajenja šaranske mlađi u prvoj godini. Pored najboljeg prirasta, šaranska mlađ hranjena sa 5% hrane je imala i najbolji faktor kondicije, specifičnu stopu rasta, kao i termalni koeficijent rasta. U odnosu na ribe hranjene sa 3 i 4% hrane, mlađ hranjena sa 5% je imala nešto veći koeficijent konverzije (za oko 10%), međutim imajući u vidu značajnu razliku u prirastu između svake od 4 hrane, ovo povećanje koeficijenta konverzije je ekonomski opravdano

Novel Quorum Quenching YtnP Lactonase From Bacillus paralicheniformis Reduces Pseudomonas aeruginosa Virulence and Increases Antibiotic Efficacy in vivo

Bacterial infections have become increasingly difficult to treat due to the occurrence of antibiotic-resistant strains. A promising strategy to increase the efficacy of therapy is to combine antibacterials with agents that decrease pathogen virulence via the modulation of the quorum sensing (QS). Lactonases inhibit acylated homoserine lactone (AHL)-mediated QS in Gram-negative bacteria, including the leading nosocomial pathogen Pseudomonas aeruginosa. Here we describe the characteristics of heterologously expressed YtnP lactonase from Bacillus paralicheniformis ZP1 (YtnP-ZP1) isolated from agricultural soil using the culture enrichment method. Purified YtnP-ZP1 hydrolyzed different AHLs with preference to substrates with long acyl residues as evaluated in assays with biosensors and HPLC. The enzyme showed good thermostability and activity in a wide temperature range. YtnP-ZP1 in 50 μg mL–1 concentration reduced the amount of P. aeruginosa-produced long-chain AHLs by 85%, while it hydrolyzed 50% of short-chain AHLs. Incubation of P. aeruginosa PAO1 with YtnP-ZP1 reduced its swarming motility and elastolytic activity without bactericidal effect. YtnP-ZP1 caused the inhibition of biofilm formation and disintegration of mature biofilms in P. aeruginosa PAO1 and multiresistant clinical strain BR5H that was visualized by crystal violet staining. The treatment with YtnP-ZP1 in concentrations higher than 25 μg mL–1 improved the survival of P. aeruginosa PAO1-infected zebrafish (Danio rerio), rescuing 80% of embryos, while in combination with tobramycin or gentamicin survival rate increased to 100%. The treatment of P. aeruginosa PAO1 biofilms on infected zebrafish tail wounds with 50 μg mL–1 YtnP-ZP1 and 2 × MIC tobramycin led to infection clearing in 2 days. The extensive toxicity studies proved YtnP-ZP1 was non-toxic to human cells and zebrafish. In conclusion, novel YtnP-ZP1 lactonase with its effective anti-virulence activity could be used to increase the efficacy of clinically approved antibiotics in clearing both systemic and biofilm-associated P. aeruginosa infections

Evaluation of growth and histology of liver and intestine in juvenile carp (Cyprinus carpio, L.) fed extruded diets with or without fish meal

Growth and histology of intestine and liver of carp fed diets with or devoid of fish meal (FM) was studied. Carp were fed four experimental diets formulated to contain 38% protein for 90 days. FM was incorporated at 30% in feed A, 15% in feed B and C, and was completely replaced with a mixture of plant proteins in feed D. Feed C and D were supplemented with methionine and lysine. The results showed that carp fed feed D had the lowest weight gain, length and\ud height compared to the other three diets, whereas no differences were observed between A, B and C for the measured morphometric parameters. Inclusion of methionine and lysine tended to improve SGR of carp fed feed C compared to those fed feed B, but growth rate was lower than carp fed feed A. FCR differed for nearly 90 % between the FM rich and solely plant protein diet. No major pathological changes were recorded. At the end of the study\ud shortening of intestinal folds’ length was found for all groups, except for fish fed feed D. The height of enterocytes was significantly lower for carp fed diet D compared to other diets. According to the results obtained the best diet is feed A, but feed C with 15% FM and added methionine and lysine represents an acceptable replacement due to its lower price and effect on growth that are the most similar to feed A

Mogućnost zamene ribljeg brašna sojinim koncentratom u ishrani pastrmke

U uslovima intenzivnog gajenja kalifornijske pastrmke (Oncorhynchus mykiss), troškovi ishrane čine 50 do 70% ukupnih troškova u proizvodnji. Tokom višegodišnjih istraživanja, došlo se do zaključaka da proteinska hraniva biljnog porekla u određenoj meri mogu da zamene riblje brašno (FM) i smanje troškove proizvodnje. Najčešće korišćeni biljni proteini u ishrani riba su sojini proizvodi. Međutim, uspešnost zamene ribljeg brašna zavisi od vrste ribe koja se gaji, uzrasta riba kao i tipa korišćenog sojinog proizvoda. Kao jedan od boljih alternativnih izvora proteina navodi se sojin proteinski koncretat (SPC). SPC se dobija ekstrakcijom proteina iz sojinog brašna i sadrži oko 70% proteina. U akvakulturi predstavlja dobru zamenu za riblje brašno, jer sadržaj i svarljivost proteina u SPC su slični kao u FM. Neutralnog je ukusa i standardno je dobrog kvaliteta u odnosu na promenljiv kvalitet FM. Istraživanje je sprovedeno u „Centru za ribarstvo i primenjenu hidrobiologiju“ ODPF Radmilovac. Mlađ kalifornijske pastrmke, prosečne nasadne mase 33,62g, hranjena je smešama koncentrata (44/20 Extra, proizvođača Veterinarski zavod Subotica) sa različitim procentualnim učešćem FM:SPC, i to: 100:0, 75:25, 50:50, 25:75 i 0:100. Na osnovu dobijenih rezultata, nakon 60 dana hranjenja riba smešama koncentrata sa različitim učešćem FM i SPC, mogu se konstatovati statistički vrlo značajne razlike u masi i dužini tela. Najbolju završnu masu, kao i BWG, SGR, TGC i FER uz najmanji FCR imale su ribe hranjene smešom gde je odnos FM:SPC bio 75:25. Nasuprot tome, ribe hranjene smešom koncentrata bez učešća FM, imale su statistički vrlo značajno niže vrednosti BWG, SGR, TGC i FER, pri čemu je FCR bio statistički vrlo značajno veći nego upotrebom drugih smeša. Dobijeni rezultati ukazuju da je u ishrani mlađi kalifornijske pastrmke najopravdanije koristiti smešu u kojoj je odnos FM:SPC bio 75:25, kako zbog proizvodnih rezultata tako i zbog smanjenja cene koštanja samog proizvoda

Endorhizosphere of indigenous succulent halophytes: a valuable resource of plant growth promoting bacteria

The adaptability of halophytes to increased soil salinity is related to complex rhizosphere interactions. In this study, an integrative approach, combining culture-independent and culture-dependent techniques was used to analyze the bacterial communities in the endorizosphere of indigenous succulent halophytes Salicornia europaea, Suaeda maritima, and Camphorosma annua from the natural salt marshes of Slano Kopovo (Serbia). The 16 S rDNA analyses gave, for the first time, an insight into the composition of the endophytic bacterial communities of S. maritima and C. annua. We have found that the composition of endophyte microbiomes in the same habitat is to some extent influenced by plant species. A cultivable portion of the halophyte microbiota was tested at different NaCl concentrations for the set of plant growth promoting (PGP) traits. Through the mining of indigenous halotolerant endophytes, we obtained a collection representing a core endophyte microbiome conferring desirable PGP traits. The majority (65%) of the selected strains belonged to the common halotolerant/halophilic genera Halomonas, Kushneria, and Halobacillus, with representatives exhibiting multiple PGP traits, and retaining beneficial traits in conditions of the increased salinity. The results suggest that the root endosphere of halophytes is a valuable source of PGP bacteria supporting plant growth and fitness in salt-affected soils. © 2023, The Author(s)

Genomics-Based Insights Into the Biosynthesis and Unusually High Accumulation of Free Fatty Acids by Streptomyces sp NP10

Schneider O, Ilic-Tomic T, Rückert C, et al. Genomics-Based Insights Into the Biosynthesis and Unusually High Accumulation of Free Fatty Acids by Streptomyces sp NP10. FRONTIERS IN MICROBIOLOGY. 2018;9: 10.Streptomyces sp. NP10 was previously shown to synthesize large amounts of free fatty acids (FFAs). In this work, we report the first insights into the biosynthesis of these fatty acids (FAs) gained after genome sequencing and identification of the genes involved. Analysis of the Streptomyces sp. NP10 draft genome revealed that it is closely related to several strains of Streptomyces griseus. Comparative analyses of secondary metabolite biosynthetic gene clusters, as well as those presumably involved in FA biosynthesis, allowed identification of an unusual cluster C12-2, which could be identified in only one other S. griseus-related streptomycete. To prove the involvement of identified cluster in FFA biosynthesis, one of its three ketosynthase genes was insertionally inactivated to generate mutant strain mNP10. Accumulation of FFAs in mNP10 was almost completely abolished, reaching less than 0.01% compared to the wild-type strain. Cloning and transfer of the C12-2 cluster to the mNP10 mutant partially restored FFA production, albeit to a low level. The discovery of this rare FFA biosynthesis cluster opens possibilities for detailed characterization of the roles of individual genes and their products in the biosynthesis of FFAs in NP10

Expression Pattern of Long Non-Coding RNA Growth Arrest-Specific 5 in the Remission Induction Therapy in Childhood Acute Lymphoblastic Leukemia

Background: Long non-coding RNA growth arrest-specific 5 (GAS5) is deregulated in many cancers because of its role in cell growth arrest and apoptosis. Additionally, GAS5 interacts with glucocorticoid receptor, making it a potential pharmacotranscription marker of glucocorticoid (GC) therapy. In this study, we aimed at analysing GAS5 expression in the remission induction therapy phase of childhood acute lymphoblastic leukemia (ALL), in which GCs are mandatorily used, and to correlate it with therapy response. Methods: GAS5 expression was measured in peripheral blood mononuclear cells taken from 29 childhood ALL patients at diagnosis, on day 15 and day 33 ofremission induction therapy using RT-qPCR methodology. Results: Our results have shown interindividual differences in GAS5 expression at all time points. For each ALL patient, GAS5 expression was higher on day 15 in comparison to its level at diagnosis (p<0.0005). On day 33, the level of GAS5 expression decreased in comparison with day 15 (p<0.0005), but it was still significantly higher than at diagnosis for the majority of patients (p=0.001). Patients whose number of blasts on day 8 was below 100 per mL of peripheral blood had a higherGAS5 expression at diagnosis (p=0.016), and lower ratio day 15/diagnosis (p=0.009). Conclusions: Our results suggest that the expression level of GAS5 could be a potential marker of therapy response in remission induction therapy of childhood ALL