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VALORE NUTRIZIONALE E PROPRIETÀ FUNZIONALI DELLA FARINA DI INSETTI NEI MANGIMI PER PESCI
No full textL’inclusione di farina di insetti nei mangimi per l’acquacoltura ha effetti positivi per la salute dei pesci, benché in letteratura siano stati riportati risultati controversi sulle prestazioni di crescita e sulla biodisponibilità dei nutrienti. Ciò sembra essere dovuto al contenuto di chitina presente nella farina di insetti, che sembra avere un’azione dose-risposta nel metabolismo dei pesci. Alla luce di queste considerazioni, sono state condotte due diverse ricerche: (1) valutare la cinetica post-prandiale della funzione digestiva nella trota iridea (Oncorhynchus mykiss) come strumento pratico a fini nutrizionali, (2) valutare l'effetto in vitro e in vivo della chitina nei mangimi per la trota iridea. Il capitolo 1 tratta il valore nutrizionale e le proprietà funzionali della farina d’insetto nei mangimi per pesci, soffermandosi sulla necessità di una produzione mangimistica sostenibile. Inoltre, si considera l’inclusione degli insetti come potenziale fonte di nutrienti, e i suoi effetti sulle prestazioni di crescita, sulla digeribilità dei nutrienti, sulla funzionalità intestinale, sulla capacità antiossidante, sulla risposta immunitaria e sulla resistenza alle malattie. Il capitolo 2 illustra i risultati presenti in letteratura sull'effetto della chitina sul metabolismo dei pesci, sugli effetti della chitina, sulla performance di crescita, sulla modulazione del microbiota, sulla risposta immunitaria e sull’effetto antinfiammatorio; inoltre, sono state descritte le proprietà chimiche della chitina, le sue possibili applicazioni, la sua determinazione analitica e la sua digestione enzimatica. Ogni ricerca volta ad ampliare la conoscenza dell’effetto della chitina negli aquafeed risulta quindi estremamente interessante. I capitoli successivi andranno a investigare livelli crescenti di chitina, in vivo e in vitro, somministrata alla trota iridea. A tal proposito, per valutare l’effetto digestivo e l’assorbimento della chitina, è stata considerata la cinetica post-prandiale nella trota iridea dopo un singolo pasto. Il capitolo 3 valuta la cinetica postprandiale dell’espressione genica degli enzimi digestivi gastrici e intestinali, dei trasportatori di nutrienti, dell’attività enzimatica della Brush Border Membrane (BBM) e della biochimica del sangue attraverso la spettroscopia NMR nella trota iridea alimentata con mangimi commerciali. I risultati mostrano che l’espressione dei geni coinvolti nella digestione e nel trasporto dei nutrienti, l’attività degli enzimi BBM e la presenza di metaboliti nel sangue vengono stimolati in diversi modi dalla presenza di mangime nel tratto digestivo. Il capitolo 4 si concentra sull'effetto in vitro di diversi livelli di chitina sulla degradazione delle proteine, utilizzando l'estratto enzimatico ottenuto dal tratto intestinale della trota iridea, e misurando se un livello crescente di chitina (0, 1.5, 3.0, 4.5%) in una miscela altamente digeribile di proteine purificate e una formulazione completa di mangime influenza l'idrolisi delle proteine. I risultati hanno rivelato che il livello di chitina nella dieta, fino al 4.5% di inclusione, non interferisce con l'idrolisi proteica in vitro da parte delle proteasi digestive della trota iridea. Il capitolo 5 mira a valutare la risposta in vivo della trota iridea alimentata con livelli crescenti di chitina (0, 1.5, 3.0, 4.5%) in una dieta basale semi-purificata. Dopo 10 prove, i pesci sono stati soppressi per valutare le prestazioni di crescita, la digeribilità delle proteine e dei lipidi, la biochimica del sangue, l'attività degli enzimi della BBM e degli enzimi chitinolitici, l'espressione genetica degli enzimi e dei trasportatori di nutrienti, nonché delle principali citochine intestinali proinfiammatorie. Nel complesso, i risultati dimostrano una buona tolleranza della trota iridea giovanile alle diete che includono fino al 3% di chitina.Insect meal inclusion in aquafeed has been claimed to be beneficial for fish health, even if controversial results on growth performance and nutrient bioavailability have been reported in the literature. This appears to be due to the chitin content of insect meal, which seems to have a dose-response action in fish metabolism. Given these considerations, we carried out two different research, the first for the evaluation of post-prandial kinetics of digestive function in rainbow trout (Oncorhynchus mykiss) as a practical tool for nutritional studies, and the second was the evaluation of the in vitro and in vivo effect of chitin in feeds for rainbow trout.
Chapter 1 focuses on the nutritional value and functional properties of insect meal in fish feed, firstly introducing the need for sustainable aquafeed production followed by specific nutritional properties of the eight insect species authorized for aquaculture. The chapter continues reporting studies focusing on insect inclusion as potential nutrient sources in aquafeeds and the effects on growth performance, nutrient digestibility, gut functionality, antioxidant capacity, immune response, and disease resistance.
Chapter 2 shows the results of the literature revision to investigate the effect of chitin on fish metabolism. In addition to the effects of chitin on growth performance, microbiota modulation, immune response, and anti-inflammatory effect, the chemical properties, the possible application, the resource, the analytical determination, and the enzymatic digestion of chitin were also described.
Given those considerations, it could be reasonable to assume that any research aiming at expanding the knowledge of the chitin effect when included in aquafeed would be relevant. In this regard, the following chapters focus on the in vivo and in vitro evaluation of increasing levels of pure chitin carried out with rainbow trout. To have a comprehensive picture of the digestive and absorptive effect of the main factor of our study, we took into consideration the post-prandial kinetics of digestive function in rainbow trout after a single meal.
Chapter 3 evaluates the postprandial kinetics of gene expression of gastric and intestinal digestive enzymes and nutrient transporters, Brush Border Membrane (BBM) enzyme activity, and blood biochemistry through NMR spectroscopy in rainbow trout (Oncorhynchus mykiss) fed a commercial aquafeed. The results showed that the expression of the genes involved in digestion and nutrient transport, the activity of BBM enzymes, and the presence of metabolites in blood were stimulated in different ways by the presence of feed in the digestive tract.
Chapter 4 focuses on the in vitro effect of different chitin levels on protein degradation using the enzymatic extract obtained from the intestinal tract of rainbow trout. The in vitro assay investigated if and to what extent a graded increasing level of chitin (0, 1.5, 3.0, and 4.5%) in a highly digestible blend of purified proteins and a complete aquafeed formulation could affect protein hydrolysis. Overall results revealed that the dietary chitin level, until 4.5% of inclusion, does not interfere with the in vitro protein hydrolysis by digestive proteases of rainbow trout.
Chapter 5 aims to assess the in vivo response of rainbow trout (Oncorhynchus mykiss) when fed with increasing levels of chitin (0, 1.5, 3.0, and 4.5%) in a semi-purified basal diet. After 10 trials, fish were euthanized for the evaluation of growth performance, protein and lipids digestibility, blood biochemistry, brush border membrane enzyme and chitinolytic enzymes activity, gene expression of enzymes and nutrients transporters as well as the major pro-inflammatory intestinal cytokines. Overall, the results demonstrate a good tolerance of juvenile rainbow trout to diets including up to 3% chitin inclusion
Effect of feed restriction and refeeding on body condition, digestive functionality and intestinal microbiota in rainbow trout (Oncorhynchus mykiss)
No full text: The aim of the present work was to investigate the influence of fasting and refeeding on body condition, gut physiology and microbiota in reared O. mykiss. Ninety-six fish were randomly allotted among three groups subjected to different feeding plan: C (control, fed for 5 weeks); R (restricted ration over 3 weeks followed by 2 weeks feeding); F (fasted over 3 weeks followed by 2 weeks feeding) in a well's fresh water flow-through rearing plan. Sampling occurred at 0, 1, 2, 4, 7, 14 days during the refeeding period. At day 0 and throughout the feeding period until day 14, the weight of the fish was significantly affected by the feeding restriction. Feed deprivation reduced significantly the viscerosomatic and hepatosomatic indexes. Brush border membrane enzymes' specific activity was modulated by feeding regimes until day 7, to level in all experimental groups at day 14. At the end of the restricted/fasted period, the microbiota of the C group was made up of 70% of Actinobacteria, 24% of Proteobacteria, 4.2% of Firmicutes and < 1% of Bacteroides, while the restricted and fasted group were characterized by a strong reduction of Actinobacteria, and a significant increase in Bacteroidetes and Firmicutes. The feed deprivation determined a dysbiosis, allowing the development of different commensal or pathogenic bacteria. In conclusion, the effects of 2 weeks of feed deprivation, excluding those related to body weight, are gradually mitigated by refeeding, which allows the restoration of digestive functions and a healthy intestinal microbiota
Single-cell proteins polyhydroxyalkanoates-rich microbial biomass from municipal and winery waste as potential additive for aquafeeds
Full text linkThis study evaluated single-cell protein production from PHA-rich mixed microbial cultures obtained from fermentation and subsequent PHA storage, using urban (namely food waste and municipal sewage sludge; FW-MSS) and agricultural waste (namely wine lees; WL) streams as substrates. FW-MSS fermentation achieved stable short-chain fatty acid (SCFA) production and a high CODSCFA/CODSOL ratio of 0.77 ± 0.01, which allowed to select a mixed microbial culture (MMC) with intracellular PHA content of 15.1 wt%, which aligns with fish dietary standards and yielded a MMC biomass with a protein level of 55.1 wt% and a balanced essential amino acid (EAA) profile. In contrast, WL fermentation showed lower SCFA content and stability, yielding a MMC with 45.8 wt% of protein along with a high non-conformance rate (53.65 %), and 7.2 wt% PHA, making the resulting MMC more suited as a supplemental protein source. Distinct microbial communities developed in the two SBRs due to different feedstocks, influencing the abundance of PHA-storing bacteria, with no known fish pathogens detected in either sample. Statistical analysis confirmed FW-MSS's superior product consistency, supporting its potential as a good quality SCP for aquafeed, especially for rainbow trout, as confirmed by its high essential amino acid index (EAAI)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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