213 research outputs found
Effects of partially defatted Hermetia illucens meal in rainbow trout diet on hepatic methionine metabolism.
This study investigated, for the first time, the effects of replacement of fishmeal (FM) with insect meal from Hermetia illucens (HI) on the transcript levels of three genes involved in methionine (Met) metabolism in rainbow trout (Oncorhynchus mykiss) liver. Two target genes\u2014betaine-homocysteine S-methyltransferase (BHMT) and S-adenosylhomocysteine hydrolase (SAHH)\u2014are involved in Met resynthesis and the third one\u2014cystathionine \u3b2 synthase (CBS)\u2014is involved in net Met loss (taurine synthesis). We also investigated the levels of two Met metabolites involved in the maintenance of methyl groups and homocysteine homeostasis in the hepatic tissue: S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH). Three diets were formulated, an FM-based diet (HI0) and two diets in which 25% (HI25) and 50% (HI50) of FM was replaced with HI larvae meal. A 78-day feeding trial involved 360 rainbow trout with 178.9 \ub1 9.81 g initial average weight. Dietary replacement of up to 50% of FM with HI larvae meal, without any Met supplementation, did not negatively affect rainbow trout growth parameters and hepatic Met metabolism. In particular, Met availability from the insect-based diets directly modulated the transcript levels of two out of three target genes (CBS, SAHH) to maintain an optimal level of one-carbon metabolic substrates, i.e., the SAM:SAH ratio in the hepatic tissue
Uniqueness of Bogomol'nyi equations and Born-Infeld like supersymmetric theories
We discuss Bogomol'nyi equations for general gauge theories (depending on the
two Maxwell invariants and ) coupled to Higgs scalars. By analysing their supersymmetric extension,
we explicitly show why the resulting BPS structure is insensitive to the
particular form of the gauge Lagrangian: Maxwell, Born-Infeld or more
complicated non-polynomial Lagrangians all satisfy the same Bogomol'nyi
equations and bounds which are dictated by the underlying supersymmetry
algebra.Comment: 10 pages, Late
Potential of shrimp waste meal and insect exuviae as sustainable sources of chitin for fish feeds.
Aquaculture is one of the world’s fastest growing food-producing sectors, providing more than half of all fish
consumed globally for human nutrition. However, to maintain such growth and meet the increasing demand for
aquatic food, sustainable raw materials for fish feeds are needed. In this regard, insects represent one of the most
promising alternatives to fish meal (FM) protein source for use in aquafeeds. In addition to protein, insects
contain bioactive compounds, such as chitin, which is a natural polysaccharide abundantly present in the pupal
exuviae of some insects. Studies have shown that dietary chitin or its derivate chitosan acts as a prebiotic thus
modulating the gut microbial communities of fish. Accordingly, the present study aimed to evaluate the effect of
two waste products rich in chitin, i.e., shrimp head meal (SHM), and insect (Hermetia illucens) pupal exuviae on
the gut microbiota of rainbow trout (Oncorhynchus mykiss). Three isoproteic, isolipidic, and isoenergetic diets
containing either FM, SHD, or a combination of FM and 1.6% of pupal exuviae meal (PEM) were tested through a
91-day feeding trial. At the end of the experiment, no differences in final mean body weight, specific growth rate,
and feed conversion ratio values were observed between fish experimental groups. Mortality was <1% and it did
not correlate with diet for the entire duration of the trial. However, a modulatory effect of dietary pupal exuviae
on fish gut microbiota was detected. Indeed, gut bacterial species richness improved by including insect exuviae.
In particular, Firmicutes and Actinobacteria phyla, mainly represented by Bacillus, Facklamia, Brevibacterium, and
Corynebacterium genera, were enriched in trout receiving pupal exuviae. These genera are chitinolytic and shortchain fatty acids (SCFAs)-producing bacteria. SCFAs production was confirmed by gas chromatography analysis,
which detected the highest amount of butyrate in feces of trout fed with pupal exuviae meal. Functional inference
analysis of intestinal microbiota using PICRUST metagenome prediction tool, showed differences in response to
diet. In particular, eleven pathways were significantly different between control fish (FM) and fish fed the PEM
diet, whereas twenty functional traits were significantly different between the FM and SHM fish groups. Overall,
our data confirmed that chitin from insect’s pupal exuviae represents a promising functional ingredient, better
than SHM, for positively modulating gut microbiota communities of rainbow trout
Portal vein thrombosis may alter the correct evaluation of hepatocellular carcinoma with the sonographic contrast pulse sequence technique
[No abstract available
Effect of partial substitution of fishmeal with insect meal (Hermetia illucens) on gut neuromuscular function in Gilthead sea bream (Sparus aurata)
Alternative nutrient sources to fishmeal for fish feed, such as insect meals, represent a promising sustainable supply. However, the consequences for fish digestive function have not been exhaustively investigated. In the present study we evaluated the effect of partial fishmeal substitution with 10% Hermetia illucens (Hi10) larvae meal on the neuromuscular function of proximal and distal intestine in gilthead sea bream. In animals fed with insect meal, weight and growth parameters were similar to controls fed with conventional fishmeal. In addition, no anomalies in intestinal gross morphology and no overt signs of inflammation were observed. The gastrointestinal transit was significantly reduced in Hi10 fed animals. In the proximal and distal intestine longitudinal muscle, Hi10 feeding downregulated the excitatory cholinergic and serotoninergic transmission. Sodium nitroprussideinduced inhibitory relaxations increased in the proximal intestine and decreased in the distal intestine after Hi10 meal. Changes in the excitatory and inhibitory components of peristalsis were associated with adaptive changes in the chemical coding of both proximal and distal intestine myenteric plexus. However, these neuromuscular function alterations were not associated with considerable variations in morphometric growth parameters, suggesting that 10% Hi meal may represent a tolerable alternative protein source for gilthead sea bream diets
New value from food and industrial wastes - bioaccumulation of omega-3 fatty acids from an oleaginous microbial biomass paired with a brewery by-product using black soldier fly (Hermetia illucens) larvae.
Research on bioconversion based on insects is intensifying as it addresses the problem of reducing and reusing
food and industrial waste. To reach this goal, we need to find more means of pairing waste to insects. With this
goal, brewers\u2019 spent grains (BSG) - a food waste of the brewing industry - paired with the oleaginous biomass of
the thraustochytrid Schizochytrium limacinum cultivated on crude glycerol - a major waste of biodiesel production
- were successfully used to grow Hermetia illucens larvae. Combining BSG and S. limacinum in the diet in an
attempt to design the lipid profile of H. illucens larvae to contain a higher percentage of omega-3 fatty acids is
novel. Insect larvae were grown on three different substrates: i) standard diet for Diptera (SD), ii) BSG, and iii) BSG + 10% S. limacinum biomass. The larvae and substrates were analyzed for fatty acid composition and larval growth was measured until 25% of insects reached the prepupal stage. Our data showed that including omega-3-rich S. limacinum biomass in the BSG substrate promoted an increase in larval weight compared to larvae fed on SD or BSG substrates. Furthermore, it was possible, albeit in a limited way, to incorporate omega-3 fatty acids, principally docosahexaenoic acid (DHA) from BSG + S. limacinum substrate containing 20% of DHA into the larval fat (7% DHA). However, H. illucens with this level of DHA may not be suitable if the aim is to get larvae with high omega-3 lipids to feed carnivorous fish
Bogomol'nyi Bounds and the Supersymmetric Born-Infeld Theory
We study N=2 supersymmetric Born-Infeld-Higgs theory in 3 dimensions and
derive Bogomol'nyi relations in its bosonic sector. A peculiar coupling between
the Higgs and the gauge field (with dynamics determined by the Born-Infeld
action) is forced by supersymmetry. The resulting equations coincide with those
arising in the Maxwell-Higgs model. Concerning Bogomol'nyi bounds for the
vortex energy, they are derived from the N=2 supersymmetry algebra.Comment: 24 pages, Latex fil
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