Metabolic response of yellow mealworm larvae to two alternative rearing substrates.

INTRODUCTION: Mass insect rearing is becoming increasingly pursued by food and feed industry due to its high sustainability and low environmental impact. Yellow mealworm larvae (Tenebrio molitor) are conventionally reared on wheat bran (WB), but alternative substrates, such as several by-products of the agri-food industry, have shown good prospects for insect rearing. OBJECTIVES: The objective of this study was to investigate on the metabolic and nutritional response of yellow mealworm larvae to dried brewer's spent grains (BSG) and WB used as rearing substrates. METHODS: Proximate, fibre and fatty acid compositions of durum WB and dried BSG were first characterized. Mealworm larvae were fed either WB (WB-L) or BSG (BSG-L) in a trial reproducing a scale rearing condition. Feed efficiency parameters together with proximate and FA composition were determined. Metabolic pathways affected by the dietary treatments were evaluated by means of a targeted metabolomics approach. Proton nuclear magnetic resonance (1H NMR) spectra were acquired on lipid and polar extracts of WB-L and BSG-L and then coupled to multivariate data analysis. Absolute quantitative 1H NMR data were carried out on selected metabolites. RESULTS: BSG-L exhibited better feed conversion ratio and efficiency in conversion of ingested food (P < 0.05) and almost half fat content (P < 0.001) than WB-L. BSG-L also showed higher ω-3 and ω-6 poliunsaturated fatty acids (P < 0.001) and lower content of monounsaturated fatty acids (P < 0.001) than WB-L. BSG-L mobilized body fat towards methylamine accumulation and led to enhanced trehalose catabolism. CONCLUSIONS: Our findings are useful to gain knowledge on the metabolic features that finally affect growth and body composition in reared yellow mealworm larvae.

Molecular details on gilthead sea bream (Sparus aurata) sensitivity to low water temperatures from 1H NMR metabolomics.

Biometric and metabolic responses of gilthead sea bream to cold challenge are described following a growth trial divided into three water temperature steps, namely cooling, cold maintenance and recovery. Experimental data provide a useful description of fish response to thermal stress at both zootechnical and molecular level. Although no mortality has been observed, Nuclear Magnetic Resonance-based metabolomics confirms the marked sensitivity of this fish species to low water temperature, and explains some key molecular events associated to fish response to cold. Increase in hepatosomatic index is associated to liver fat accumulation, as a consequence of lipid mobilization from muscle and other extrahepatic tissues, and metabolic rearrangements linked to homeoviscous adaptation of cellular membranes are observed. Following primary responses to descending temperature from 18°C to 11°C, the energetic metabolism (insulin signaling, glycolysis) is first clearly affected; then, at constant low water temperature (11°C), the most perturbed metabolic pathways are related to methionine cycle in liver, while osmoregulatory function is exerted by TMAO in muscle. Water temperature recovery from 11°C to 18°C stimulates gluconeogenesis and glycogen synthesis activities at hepatic level, although the rate of a thermo-compensatory response seems to be slower than that of the cooling phase. The obtained results are intended to guide novel high-performance feed formulations for gilthead sea bream reared during winter.

Territorial origin of olive oil: representing georeferenced maps of olive oils by NMR profiling.

Proton NMR profiling is nowadays a consolidated technique for the identification of geographical origin of food samples. The common approach consists in correlating NMR spectra of food samples to their territorial origin by multivariate classification statistical algorithms. In the present work, we illustrate an alternative perspective to exploit territorial information, contained in the NMR spectra, which is based on the implementation of a geographic information system (GIS). Nuclear magnetic resonance spectra are used to build a GIS map permitting the identification of territorial regions having strong similarities in the chemical content of the produced food (terroir units). These terroir units can, in turn, be used as input for labeling samples to be analyzed by traditional classification methods. In this work, we describe the methods and the algorithms that permit to produce GIS maps from NMR profiles and apply the described method to the analysis of the geographical distribution of olive oils in an Italian region. In particular, we analyzed by 1 H NMR up to 98 georeferenced olive oil samples produced in the Abruzzo Italian region. By using the first principal component of the NMR variables selected according to the Moran test, we produced a GIS map, in which we identified two regions incidentally corresponding to the provinces of Teramo and Pescara. We then labeled the samples according to the province of provenience and built an LDA model that provides a classification ability up to 99% . A comparison between the variables selected in the geostatistics and classification steps is finally performed. Copyright © 2016 John Wiley & Sons, Ltd.

The metabolic footprint of Vero E6 cells highlights the key metabolic routes associated with SARS-CoV-2 infection and response to drug combinations.

SARS-CoV-2 burdens healthcare systems worldwide, yet specific drug-based treatments are still unavailable. Understanding the effects of SARS-CoV-2 on host molecular pathways is critical for providing full descriptions and optimizing therapeutic targets. The present study used Nuclear Magnetic Resonance-based metabolic footprinting to characterize the secreted cellular metabolite levels (exometabolomes) of Vero E6 cells in response to SARS-CoV-2 infection and to two candidate drugs (Remdesivir, RDV, and Azithromycin, AZI), either alone or in combination. SARS-CoV-2 infection appears to force VE6 cells to have increased glucose concentrations from extra-cellular medium and altered energetic metabolism. RDV and AZI, either alone or in combination, can modify the glycolic-gluconeogenesis pathway in the host cell, thus impairing the mitochondrial oxidative damage caused by the SARS-CoV-2 in the primary phase. RDV treatment appears to be associated with a metabolic shift toward the TCA cycle. Our findings reveal a metabolic reprogramming produced by studied pharmacological treatments that protects host cells against virus-induced metabolic damage, with an emphasis on the glycolytic-gluconeogenetic pathway. These findings may help researchers better understand the relevant biological mechanisms involved in viral infection, as well as the creation of mechanistic hypotheses for such candidate drugs, thereby opening up new possibilities for SARS-CoV-2 pharmacological therapy.

Quality Evaluation of Fresh Pasta Fortified with Sourdough Containing Wheat Germ and Wholemeal Semolina.

Pasta is a staple food in the Mediterranean diet, primarily manufactured with two essential ingredients, semolina and water; nowadays, it is often supplemented with functional ingredients. In this work, a sourdough obtained with wheat germ and wholemeal semolina was used, in order to improve sensorial and nutritional properties of fresh pasta, to prevent lipids oxidation, and to improve the shelf life. Three different formulations were prepared, a first one using semolina, a second one with raw wheat germ, wholemeal semolina, and semolina, and the last one with semolina and sourdough. The study highlighted the improved nutritional properties of pasta with sourdough (reduced phytic acid content, higher antioxidant activity and phenolic content). Proteins, ashes, dietary fibers, lipids, and tocols (vitamin E) increased in pasta with wheat germ and wholemeal semolina, and with sourdough. The amount of tocols decreased in pasta samples after cooking, except for the ß-tocopherol in sourdough pasta, the amount of which remained high, surprisingly. Lipase and lipoxygenase enzymes likely decreased as an effect of the pasteurization process. The NMR analysis showed that lipid oxidation was higher in semolina pasta than in pasta with wheat germ, most likely due to the protective effect of antioxidants deriving from wheat germ.

On the Compatibility of Fish Meal Replacements in Aquafeeds for Rainbow Trout. A Combined Metabolomic, Proteomic and Histological Study.

The sustainable development of modern aquaculture must rely on a significant reduction of the fish meal (FM) used in aquafeed formulations. However, FM substitution with alternative ingredients in diets for carnivorous fish species often showed reduced nutrient absorption, significantly perturbed metabolisms, and histological changes at both hepatic and intestinal levels. In the present study, rainbow trout (Oncorhynchus mykiss) were fed three different experimental aquafeeds. A control diet with higher FM content (27.3%) than two test formulations in which FM was substituted with two more sustainable and promising alternatives: insect meal (Hermetia illucens larvae = 10.1%, FM = 11.6%) and poultry by-products meal (PBM = 14.8%; FM = 11.7%). Combined metabolomics and proteomics analyses of fish liver, together with histological examination of liver and intestine demonstrated that a well-balanced formulation of nutrients in the three diets allowed high metabolic compatibility of either substitution, paving the way for a deeper understanding of the impact of novel raw materials for the fish feed industry. Results show that the main metabolic pathways of nutrient absorption and catabolism were essentially unaltered by alternative feed ingredients, and also histological alterations were negligible. It is demonstrated that the substitution of FM with sustainable alternatives does not have a negative impact on fish metabolism, as long as the nutritional requirements of rainbow trout are fulfilled.

Identification of milk mixtures by 1H NMR profiling.

Nuclear magnetic resonance profiling, combined with a single-layer artificial neural network, is used for the evaluation of the content of mixtures of different kinds of milk. In particular, aqueous fractions of cow and sheep milk mixtures are analyzed by (1) H NMR. The spectral differences are highlighted by an analysis of the variance and a principal component analysis. The species classification problem is solved by a linear discriminant analysis. The quantification of the relative amount of the milk of two different species is then achieved by solving the appropriate multilinear problem.

Nuclear magnetic resonance profiling of wine blends.

Nuclear magnetic resonance (NMR) profiling is used for characterization of monocultivar binary wine mixtures. Classification and quantification of the relative amount of wine in the mixture are made in two steps. First, each sample is classified as a mixture of a determined type by solving the appropriate classification problem using NMR profiles. The relative amount of the two corresponding monovarietal wines is then evaluated by multilinear regression of a selected set of NMR variables. Linear discriminant analysis (LDA), used in the classification step, gives a very good separation among the different mixture classes. On the other hand, a single layer artificial neural network, used to solve the multilinear problem, gives the relative amount of wine type in the mixture with a precision of about 10%.