As limitações ao uso de antibióticos promotores de crescimento vêm aumentando a procura por aditivos substitutos para manter a performance animal, a saúde intestinal e a resposta imune de frangos de corte. Este experimento foi conduzido para comparar o efeito e a dose resposta do produto Ava Cid P (composto por substância húmica, butirato de sódio 30% protegido e uma pequena porção de acidificantes) suplementado na dieta, sobre a performance, resposta imune e saúde intestinal de frangos de corte. O experimento seguiu um design inteiramente casualizado, envolvendo um arranjo fatorial 2 x 5 (2 sexos e 5 tratamentos) com 7 repetições de 15 aves por tratamento. Os tratamentos seguiram a suplementação em diferentes fases de 1 a 49 dias: 1) Controle: dieta basal sem nenhuma suplementação; 2) AVA1-21: aves receberam 0,91 kg/t de Ava Cid P de 1 a 21 d; 3) AVA1-35: 0,91 kg/t de Ava Cid P de 1-21 d e 0,45 kg/t de 22-35 d; 4) AVA1-42: 0,91 kg/t de Ava Cid P de 1 a 21 d e 0,45 kg/t de 22- 42 d; 5) AVA1-49: 0,91 kg/t de Ava Cid P de 1 a 21 d, 0,45 kg/t de 22-35 d e 0,23 kg/t de 36-49 d. A suplementação com Ava Cid P não influenciou a performance de machos e fêmeas, nem mesmo a densidade de células caliciformes (P > 0,05). No entanto, o Ava Cid P foi capaz de modificar a morfometria intestinal, aumentando a altura de vilosidades aos 9 e 35 d (P < 0,05). A área superficial aparente dos vilos e altura de vilos, nas aves que receberam Ava Cid P durante todas as fases experimentais, foi superior à das aves suplementadas somente na fase inicial. No íleo, a área superficial aparente dos vilos também foi superior nas aves suplementadas aos 9 d. Além disso, a expressão do gene para mucina 2 (MUC2) e para o fator de necrose tumoral (TNF-α) diminuiu nas aves recebendo Ava Cid P aos 21 d (P < 0,05), mas não foram observadas diferenças estatísticas para interleucina-1 beta e interleucina-10. Os resultados sugerem que Ava Cid P pode alterar a expressão de mRNA de algumas citocinas e MUC2 e a morfometria intestinal de frangos de corte, aumentando a superfície aparente e a altura dos vilos, o que demonstra a potencialidade do produto como alternativa aos antibióticos promotores de crescimento. / The limitations of the antibiotic growth promoter’s (AGP) usage have been increasing the search for new products to improve poultry performance, gut healthy and immune response. This experiment was conducted to compare the effect and dose response of Ava Cid P (consisted of a humic substance, coated sodium butyrate 30% and a small acidifier portion) diet supplementation on performance, immune response and gut health of broilers. Five dietary regimens were used: 1) birds didn’t receive Ava Cid P in any phase (Control), 2) birds received 0.91 kg/t of Ava Cid P from 1 to 21 d (AVA1-21), 3) 0.91 kg/t of Ava Cid P from 1 to 21 d and 0.45 kg/t from 22 to 35 d (AVA1-35), 4) 0.91 kg/t of Ava Cid P from 1 to 21 d and 0.45 kg/t from 22 to 42 d (AVA1-42), 5) 0.91 kg/t of Ava Cid P from 1 to 21 d, 0.45 kg/t from 22 to 35 d and 0.23 kg/t from 36 to 49 d (AVA1-49). They were applied in a completely randomized design, involving a 2 × 5 factorial arrangement with 2 sex and 5 levels of inclusion, and 7 replications with 15 birds each. The supplementation with Ava Cid P showed no influence on males and females growth performance and goblet cell density (P > 0.05). However, it modified the gut morphometry, increasing jejunum villi height at 9 and 35 days (P < 0.05). The apparent villus surface area and villi height on birds fed with Ava Cid P during all phases also increased in relation to those who received only in the early phase. The expression of mucin 2 (MUC2) and tumor necrosis factor-alpha (TNF-α) decreased on birds that received Ava Cid P at 21 days (P < 0.05), but no differences were seen for interleukin-1beta (IL-1β) and interleukin-10 (IL-10). The results suggest that Ava Cid P can alter the mRNA expression of some inter-leukins, MUC2 and intestinal morphometry in broilers, increasing apparent villus surface area and villi height, which demonstrates the product potential as an alternative growth promoter.

Le CTLA4 permet de maintenir la tolérance du soi et prévient le développement d’auto-immunités. Contenu au sein de vésicules intra-cytoplasmiques des lymphocytes T au repos, le CTLA4 est exprimé à la membrane plasmique suite à l’activation du TCR, on le qualifie de rétrocontrôle inhibiteur du système immunitaire (ICB). L’anticorps bloquant le CTLA4, l’ipilimumab induit un contrôle immunitaire à long terme chez une fraction de patients atteints de mélanomes métastatiques. Deux études cliniques de phase III ont conduit à son autorisation de mise sur le marché dans le traitement du mélanome métastatique par la FDA et l’EMA en 2011. Cependant le blocage du CTLA4 est souvent associé au développement d’effets indésirables liés à l’immunité, irAEs, majoritairement au niveau de la peau et de l’intestin, deux sites colonisés par la flore microbienne. Afin de continuer le développement des ICB et des combinaisons de traitements, de nombreux efforts visent à découpler l’efficacité anti-tumorale de la toxicité associée à l’anti-CTLA4. Bien que la stimulation du système immunitaire soit responsable des effets thérapeutiques de l’anti-CTLA4, aucun biomarqueur immunologique d’efficacité n’a été décrit. Dans notre première étude nous avons étudié le mécanisme d’action de l’anti-CTLA4 et nous avons décrit un rôle de l’IL-2 et de ses récepteurs dans l’activité anti-tumorale de l’anticorps. Nous avons également décrit la fraction soluble du récepteur à l’IL-2, le sCD25 comme un biomarqueur potentiel de résistance au traitement. Une concentration élevée de sCD25 dans le sérum des patients atteints de mélanome prédit la résistance à l’ipilimumab. Dans notre second projet, nous avons révélé le rôle du microbiote intestinale et particulièrement de bactéries Gram négatives, des Bacteroides, dans l’efficacité anti-tumorale de l’anti-CTLA4. L’absence d’efficacité du blocage du CTLA4 chez les animaux dépourvus de flore intestinale peut être rétablie par l’administration de Bacteroides fragilis, ou bien de DC, ou encore de lymphocytes T spécifiques de B. fragilis, sans déclencher de colites. Ces travaux suggèrent de nouvelles stratégies thérapeutiques pour espérer améliorer la balance bénéfice / toxicité / coût de l’ipilimumab. / CTLA4, cytotoxic T lymphocyte antigen-4, which is present in the intracytoplasmic vesicles of resting T cells, is upregulated at the surface of activated T cells where it maintains self-tolerance and prevents autoimmunity. The CTLA4-blocking antibody, ipilimumab, induces immune-mediated long term control of metastatic melanoma in a fraction of patients, leading to its approval by the US Food and Drug Administration (FDA) and the European Medical Agency (EMA) in 2011 for the treatment of advanced metastatic melanoma. However, blockade of CTLA4 by ipilimumab often results in immune-related adverse events (irAEs) at sites that are exposed to commensal flora, namely the gut and the skin. Uncoupling efficacy from toxicity is a challenge for the development of immune checkpoint blockers and therapeutic combinations. Although ipilimumab undoubtedly exerts its therapeutic effects via immunostimulation, relevant immune biomarkers that predict treatment efficiency remain elusive. Firstly, we unravel a role for IL-2 and IL-2 receptors in the anticancer activity of CTLA-4 blockade. Importantly, our study provides an immunologically relevant biomarker, elevated serum sCD25, which predicts resistance to CTLA-4 blockade in patients with melanoma. Secondly, we show that the antitumor effects of CTLA4 blockade depend upon intestinal Gram-negative bacteria, mostly Bacteroides species. These bacteria accumulate at the bottom of the intestinal crypts and elicit an IL-12-dependent Th1 immune response specific for distinct Bacteroides species, both in tumor bearing mice and in cancer patients. CTLA4 blockade lost its anticancer efficacy in antibiotic-treated or germ-free mice. This defect could be overcome by oral administration of Bacteroides fragilis (Bf), immunization with Bf polysaccharides, or adoptive transfer of Bf-specific T cells, all of which in the absence of colitis. Our study unravels the key role of Bacteroides in the immunostimulatory effects of CTLA4 blockade, suggesting novel strategies for safely broadening its clinical use

Il est maintenant bien établi que le microbiote du tractus digestif humain joue un rôle important dans la santé humaine. Pourtant, nous commençons à peine à comprendre les mécanismes moléculaires par lesquels les bactéries agissent sur les cellules hôtes, des connaissances qui pourraient fournir des nouvelles orientations dans le traitement et la prévention de maladies. Cette dernière décennie a vu un développement rapide des études du microbiote intestinal, et à présent des quantités importantes de données métagénomiques ainsi que des centaines de séquences génomiques de bactéries commensales sont disponibles. Ensemble, ces données fournissent une plateforme pour des approches in silico pour l'identification de molécules bactériennes impliquées dans la communication moléculaire avec l'hôte. Le défi consiste à développer des stratégies efficaces d'exploration de données et de validation, permettant de passer de corrélations et prédictions à des interactions bactérie - hôte fonctionnelles, validées expérimentalement. Le travail présenté dans cette thèse vise à démontrer l'importance d'analyses in silico afin d'élargir nos connaissances sur les interactions bactéries - hôtes. Il montre également comment cette information peut être appliquée dans des études fonctionnelles visant à identifier des molécules effectrices bactériennes fonctionnelles. Les principaux résultats peuvent être divisés en trois parties. La première partie traite de l'élaboration et de la validation d'un système hôte - vecteur pour des études de (méta)génomique fonctionnelle. La deuxième partie décrit une étude fonctionnelle où un certain nombre d'effecteurs candidats ont été identifiés parmi les protéines sécrétées et de surface de bactéries à Gram positif par une approche d'exploration in silico. Il décrit également l'application du nouveau système hôte - vecteur pour l'évaluation du rôle de ces candidats dans l'immuno-modulation. Enfin, dans la troisième partie, nous présentons une étude in silico qui a permis l'identification de fonctions bactériennes sur- ou sous-représentées dans une sélection de bactéries à Gram positif du tractus digestif humain. / It is now well established that the human gastrointestinal tract microbiota plays an intricate role in human health. However, we are only beginning to understand the molecular mechanisms by which bacteria act on the host cells, knowledge that could provide new directions in treating and preventing disease. The last decade has seen a rapid development of the gut microbiota field, and presently abundant metagenome data and hundreds of genome sequences of individual commensal bacteria are available. Together, these data provide a platform for in silico mining approaches to identify bacterial molecules involved in communication with the host. The challenge is to develop efficient mining and validation strategies, in order to move from correlations and predictions to experimentally validated functional bacteria – host relationships. The work presented in this thesis aims to demonstrate the importance of in silico analyses to broaden our knowledge on bacteria - host interactions. It also shows how this information can be applied in functional studies aiming to identify functional bacterial effector molecules. The main results can be divided in three parts. The first part deals with the development and validation of a host - vector system for functional (meta)genomics studies. The second part describes a functional study where a number of candidate effectors were identified among secreted and surface-exposed proteins from Gram-positive bacteria using an in silico mining approach. It also describes the application of the newly developed host - vector system to evaluate the role of these candidates in immune modulation. Finally, in the third part we present an in silico study that identified new bacterial functions over- or under-represented in a selection of Gram-positive human gut bacteria.

The Mediterranean diet (Medi) has been highlighted as the golden diet rich in protective properties associated with cognitive- and emotional health. The foundation of the Medi comprises vegetables, fruits, nuts and seeds, legumes, and extra virgin olive oil. Research has been conducted in both holistic dietary approach and single nutrient approach regarding the impact of nutrition and diet, in this case, the Medi‟s effect on brain health. This review aims to give an up to date overview of the Mediterranean diet, outline some of the diet's abundant nutrients, and discuss studies linking the nutrient's potential effect on depression, cognitive decline, dementia, and brain structure and function. In addition, this review will attempt to assess whether the Medi as a whole or if a single nutrient approach is accountable for the health-promoting findings. Furthermore, the gut-brain axis, and other potential underlying mechanisms involved in the modulation of food- and nutrient intake and their effects on the brain, will be outlined. A diet high in fruit-, vegetable-, polyunsaturated fatty acid-, and monounsaturated fatty acid content has great power for health-maintenance and decreases the risk of suffering cognitive decline, dementia, and potentially depression. More randomized controlled trials are however eagerly awaited to give more substance to previous findings.

From animal experimentation, and studies using in vitro models, there was evidence in the literature to suggest that dietary fibre may influence contractility and motility of the gastrointestinal tract and long chain (LC) n-3 polyunsaturated fatty acids (PUFAs) from marine sources may influence contractility of smooth muscle cells in blood vessels. The hypothesis of this thesis was that dietary fish oil and/or fibre influence the contractility of isolated intact sections of gut smooth muscle tissue from small animal models. Methodology was established to measure in vitro contractility of intact pieces of guinea pig ileum with the serosal side isolated from the lumen. It was demonstrated that four amino acid peptides from κ-casein (casoxins) applied to the lumen overcame morphine-induced inhibition of contraction. Using this established technology, the guinea pig was used to investigate the effects of dietary fibre and fish oil supplementation on gut in vitro contractility. In separate experiments, changes in sensitivity to electrically-driven and 8-iso-prostanglandin (PG)E₂-induced contractility were demonstrated for dietary fibre and fish oil. A modified, isolated gut super-perfusion system was then established for the rat to validate these findings. It was subsequently shown that LC n-3 PUFA from dietary fish oil significantly increased maximal contraction in response to the G-protein coupled receptor modulators, acetylcholine and the eicosanoids PGE₂, PGF₂α, 8-iso-PGE₂ and U-46619 in ileum but not colon, without changes in sensitivity (EC₅₀), when n-3 PUFA as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) had been incorporated to a similar degree into the gut total phospholipid membrane pool. It was further established that the spontaneously hypertensive rat (SHR) had a depressed prostanoid (PGE₂and PGF₂α) response in the gut that could be restored by dietary fish oil supplementation (5% w/w of total diet) in the ileum but not the colon. Importantly, the muscarinic response in the colon of the SHR was increased by fish oil supplementation with DHA likely to be the active agent. Dietary fish oil dose experiments deduced differential increases in response occurred at fish oil concentrations of 1% for muscarinic and 2.5% (w/w) for prostanoid stimulators of the ileum with no difference in receptor-independent KCl-induced depolarization-driven contractility. Studies combining high amylose resistant starch (HAMS, 10% w/w) and fish oil (10% w/w) fed to young rats demonstrated a low prostanoid response that was enhanced by dietary fish oil but not resistant starch. There was however, an interactive effect of the HAMS and fish oil noted for the muscarinic-mimetic, carbachol. Generally, resistant starch increased the large bowel short chain fatty acid pool with a subsequent lower pH. Binding studies determined that while the total muscarinic receptor binding properties of an isolated ileal membrane fraction were not affected in mature rats by dietary fish oil, young rats had a different order of muscarinic receptor subtype response with a rank order potency of M₃ > M₁ > M₂ compared to mature animals of M₃ > M₂ > M₁ with fish oil altering the sensitivity of the M₁ receptor subtype in isolated carbachol-precontracted ileal tissue. In conclusion, experiments using the guinea pig and rat gut models demonstrated that dietary fish oil supplementation, and to a lesser degree fibre, increased receptor-driven contractility in normal and compromised SHR ileum and colon. Further, changes in responsiveness were demonstrated in the developing rat gut prostanoid and muscarinic receptor populations that could be altered by dietary fish oil. Preliminary evidence suggested that fish oil as DHA may alter receptor-driven gut contractility by mechanisms involving smooth muscle calcium modulation. Defining the role that dietary fibre and fish oil, and other nutrients, play in normal and diseased states of bowel health such as inflammatory bowel disease (IBD), where contractility is compromised, are among the ongoing challenges. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1316907 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2008

A recent study using human fecal samples in conjunction with a culture-independent approach revealed immense diversity of antibiotic resistance (AR) genes in the human gut microflora. We hypothesize that food animal gut microflora also contain diverse and novel AR genes which could contribute to the emergence and transmission of AR in pathogens important in animal and human health. To test this, we examined AR reservoir in chicken gut microflora using a metagenomic, functional cloning method. Total genomic DNA was extracted from individual cecal contents of two free range chickens and two conventionally raised chickens. The DNAs were physically sheered into 1 to 3 kb fragments, cloned into expression vector pZE21-MCS, and transformed into E. coli TOP10 host strain, resulting in four metagenomic libraries of a total size of 108 base pairs per library. The AR transformants from the libraries were selected on plates containing the specific antibiotic of interest; six antibiotics including ampicillin, tetracycline, chloramphenicol, spectinomycin, ciprofloxacin and norfloxacin were used for screening. Plasmids from selected transformants were extracted and subjected to sequence analysis of inserted fragments. Identified AR genes were annotated and aligned with homologs that have been deposited in GenBank. A total of 12 AR genes and 3 AR genes were identified from the microbiome in conventionally raised chickens and free-range chickens, respectively. Of the identified 15 AR genes, 8 genes that confer resistance to ampicillin, spectinomycin or chloramphenicol shared low sequence similarity (58% - 76% at amino acid level) with the corresponding AR genes previously identified using culture-dependent approaches. Notably, among the 8 novel AR genes identified in this study, 4 genes also shared low sequence similarities (59%-76% at amino acid level) with recently identified AR genes in human gut. An E. coli-Campylobacter shuttle vector bearing the flaA sigma 28 promoter was constructed. Two novel genes conferring resistance to ampicillin (FRAmp1.1) and spectinomycin (FRSpe1.1) were cloned into this new expression vector, respectively. The derived vectors have conferred increased AR in C. jejuni, a leading zoonotic bacterial pathogen causing human gastroenteritidis in many industrialized countries. Together, findings from this study showed the effectiveness of the metagenomic approach for examination of AR reservoir in food animals, revealed novel AR resistance genes in chicken gut microflora, and demonstrated the functionality of such AR genes in foodborne human pathogens.

突變生成(mutagenesis)的方式有許多種，其中insertional mutagenesis為果蠅上常使用建立突變株的方式，本篇論文利用p[GawB]隨機插入果蠅genome中產生大量突變株，並篩選出會影響壽命的突變果蠅M2。進一步的實驗發現M2果蠅為Vha16-1基因的突變，並造成其mRNA表現量的下降，且在低卡路里(5% yeast、5% dextrose)與高卡路里(15% yeast、15% dextrose)的環境下homozygous mutant果蠅皆有減少平均壽命的現象。 Vha16-1所表現的蛋白為Vacuolar-type H+-ATPase (V-ATPase)上的subunit c，V-ATPase主要的功能為藉由消耗ATP來運送氫離子，並可調節胞器或胞外腔室的酸鹼平衡。V-ATPase主要表現在果蠅腸道的copper cell上，此細胞的功能類似於哺乳動物的胃壁細胞(parietal cells)，與胃酸的分泌有關，我們發現M2 homozygous mutant果蠅因Vha16-1基因的缺失而有減少腸道酸化的情形發生，符合我們觀察到其在腸道上的表現。此一現象亦在另一株突變果蠅Vha16-1EP2372上加以證實。先前研究顯示果蠅腸道酸鹼平衡的破壞會影響到對養分的吸收，而Vha16-1的缺失亦導致M2果蠅體重與三酸甘油酯的上升，並增加對飢餓的耐受性，而這些代謝上的變化並不會改變M2果蠅對食物的攝取量或者生育能力。綜合這些實驗結果，我們推測Vha16-1基因的缺失會改變腸道功能，並影響果蠅體內代謝的狀態，表現出類似肥胖(obesity)的性狀，而終導致平均壽命的縮短。 / Mutagenesis can be induced by many ways and one of the most common approaches used in Drosophila is insertional mutagenesis. In this study, we screened pGawB insertion lines and identified M2 as a novel mutant with affected lifespan. The mutant allele of M2 carried a pGawB inseration at the 5’ end of the Vha16-1 gene, which caused a reduced Vha16-1 mRNA expression level and a shorten lifespan in homozygous mutants under both low calorie (5% yeast and 5% dextrose) and high calorie (15% yeast and 15% dextrose) foods. Vha16-1 encodes the c subunit of the Vacuolar-type H+-ATPase (V-ATPase) which is known to regulate pH homeostasis by pumping protons across organelle and plasma membranes. V-ATPase is highly expressed by the Copper cells which are located at the Drosophila middle midgut and functionally similar to the gastric acid producing parietal cells in mammals. Along the same line, we found that Vha16-1 pGawB drives GFP reporter was observed along the Drosophila gastrointestinal tract. M2 as well as the other Vha16-1 hypomorphic mutant line, EP2372, also showed reduced midgut acidification. This disrupted pH homeostasis in the Drosophila midgut region may be associated with increased body weight, triglyceride, and starvation resistance that observed in M2 mutants. The feeding behavior and reproductive function, however, were not affected in M2 mutant flies. In summary, our data suggested Vha16-1 deficits may alter normal intestinal function or internal metabolic status that ultimately induces obesity phenotypes with reduced lifespan.

Se evaluaron los efectos de formulas infantiles suplementadas con poliaminas y con fructooligosacaridos a dosis fisiológicas, sobre la maduración intestinal en lechones destetados precozmente. Se alimentaron 40 cerdos neonatales con leche materna, fórmula control, fórmula suplementada con poliaminas (5 nmol/ml espermina y 20 nmol/ml espermidina) y fórmula suplementada con FOS (8 g/l) (n=10/grupo experimental) durante un periodo de 13 días (del día 2 al 15 postparto). Nuestros resultados mostraron un aumento significativo en la profundidad de las criptas a nivel de yeyuno en el grupo de animales alimentado con poliaminas. El efecto bifidogénico de los FOS se asoció con una mayor concentración de poliaminas en el contenido cecal de cerdos neonatales y con una disminución de los parámetros de maduración intestinal analizados. Las cepas seleccionadas por el consumo de FOS, Bifidobacterium spp, Lactobacillus fermentum y Lactobacillus acidophilus fueron capaces de producir poliaminas in vitro. El estudio in vitro, no mostró una relación dosis-dependiente entre la concentración de FOS y la producción de poliaminas bacterianas. / It was evaluated the effects of infant formula supplemented with polyamines and fructooligosaccharides at physiological doses on gut maturation in newborn piglets. Forty newborn piglets were fed maternal milk, a control formula, a formula supplemented with polyamines (5 nmol / ml and 20 nmol spermine / spermidine ml) or a formula supplemented with FOS (8 g/l) (n = 10/experimental group) for 13 days (day 2 after birth through day 15). Animals fed polyamines showed a significant increase in crypt depth of jejunum. The bifidogenic activity of FOS was associated with an increased polyamine concentration in the cecal content of piglets and a decrease in gut maturation parameters analyzed. The Bifidobacterium spp., L. fermentum and L. acidophilus, the most predominant strains after FOS supplementation, were able to produce polyamines in vitro. However, there was not a dose-dependent relationship between FOS addition to the bacterial cecal content and polyamine production in vitro.

This article experimentally examines voluntary contributions when group members' marginal returns to the public good vary. The experiment implements two marginal return types, low and high, and uses the information that members have about the heterogeneity to identify the applied contribution norm. We find that norms vary with the information environment. If agents are aware of the heterogeneity, contributions increase in general. However, high types contribute more than low types when contributions can be linked to the type of the donor but contribute less otherwise. Low types, on the other hand, contribute more than high types when group members are aware of the heterogeneity but contributions cannot be linked to types. Our results underline the importance of the information structure when persons with different abilities contribute to a joint project, as in the context of teamwork or charitable giving. (author's abstract) / Series: Department of Economics Working Paper Series

Il fattore antisecretivo (AF) è una proteina secreta nel plasma e nei tessuti dei mammiferi, che ha dimostrato di essere un potente inibitore dell’ipersecrezione intestinale e dell'infiammazione. Dopo il bando degli AGP, diversi approcci nutrizionali finalizzati all’ottimizzazione della fase di transizione dello svezzamento e alla riduzione delle malattie intestinali sono stati proposti, ma con scarsi risultati rispetto agli antibiotici. Le diete in grado di indurre la secrezione endogena di AF potrebbero essere una valida alternativa agli AGP. Si ritiene che AF contenuto nel colostro e nel latte delle scrofe possa essere un fattore di protezione contro la diarrea nei suinetti. E’ stato dimostrato che è possibile incrementare il livello di AF nel plasma attraverso la dieta, sia nell’uomo che negli animali, con l’ingestione di cereali sottoposti ad un particolare processo idro-termico (HPC). In questa tesi è stato studiato l’effetto dell’aggiunta di HPC alla dieta di suinetti svezzati, sulle performance e sullo stato infiammatorio dell’epitelio intestinale. La supplementazione della dieta con HPC ha migliorato ADG e FCR durante tutto il periodo sperimentale. I valori I-FABP, considerato un parametro del danneggiamento della mucosa intestinale, nel plasma dei suinetti sono risultati bassi in tutti i gruppi e non influenzati dalla dieta. L'attività antisecretiva di AF-16, il dominio attivo della proteina, è stata valutata mediate su colture cellulari IPEC-J2 trattate con tossina colerica (CT) in Ussing chamber. AF-16 non ha inibito l’incremento di Isc indotto da CT. E’ stato osservato un ridotto incremento di Isc durante la somministrazione contemporanea di AF-16 e CT. L'attività anti-infiammatoria di AF-16 è stata studiata in colture di macrofagi RAW 264,7, trattati con LPS, e su macrofagi alveolari di suino stimolati con PMA. AF-16 ha ridotto la produzione di NO nei macrofagi stimolati con LPS in funzione del dosaggio, con maggiori effetti a dosaggi più elevati. L’effetto antiinfiammatorio di AF-16 non è stata confermata dai ROS test, neanche usando dosi elevate di peptide. I risultati confermano l’efficacia dei cereali HPC come promotori della crescita nei suinetti. Ulteriori studi in vitro sono necessari per capire il meccanismo d’azione di AF. / The antisecretory factor (AF) is a protein secreted in plasma and other tissue fluids in mammalians which was shown to be a potent inhibitor of intestinal fluid secretion and inflammation. After the AGP ban, several nutritional approaches aimed to the optimization of the weaning transition and reduction of gut diseases have been proposed, but the success rates are really low compared to antimicrobials. AF-inducing diets appear to be suitable alternatives to AGP. Indeed AF content in sows’ colostrum and milk appears to be a protection factor against diarrhoea in suckling piglets. Increased AF level in plasma by dietary means, such as feeding hydro-thermally processed cereals (HPC), has been demonstrated in human and animals. We tested the effect of two different HPC level of inclusion in a wheat-barley based diet on weaned piglets growth performance, reared in an experimental farm. The results confirmed the efficacy of HPC as growth promoters in piglet nutrition: HPC supplementation improved ADG and FCR. In vitro test were made to study the antisecretory and anti-inflammatory properties of the AF protein and its mechanism of action by using AF-16, the active region of the protein. The Ussing chamber experiments performed on polarized IPEC-J2 cells confirmed the neuronal involvement in the antisecretory activity of AF. In fact, AF-16 did not inhibit CT-induced Isc. A slower rate of Isc increase was observed during the simultaneous administration with AF-16 and CT. High dosages of AF-16 were found to reduce the LPS-stimulated NO production in RAW264.7 cell, thus supporting the hypothesis of an anti-inflammatory action. On the contrary, no significant results were obtained on PMA-stimulated ROS generation in pig alveolar macrophages.