Browsing by Author "Ferreira, L."
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- Biochemical and histological effects of sitagliptin on Zucker Diabetic Fatty rat pancreasPublication . Mega, C.; Vala, Helena; Teixeira de Lemos, E.; Fernandes, R.; Oliveira, J.; Ferreira, L.; Teixeira, F.; Reis, F.Background: Inhibition of dipeptidyl peptidase-4 (DPP-4) activity by sitagliptin has been shown to improve glycemic control in patients with type 2 diabetes Mellitus (T2DM) by prolonging the actions of incretin hormones, but the really impact of low-dose sitagliptin treatment on pancreas lesions is almost unknown. This study aimed to evaluate the effects of sitagliptin on biochemical and histological (pancreas) parameters of Zucker Diabetic Fatty (ZDF, fa/fa) rats, an animal model of T2DM. Methods: Diabetic (fa/fa) ZDF male rats were treated with vehicle or sitagliptin (10 mg/kg BW/day) during 6 weeks (n=8 each). The following parameters were assessed: serum glycaemia, HbA1c, insulin and lipid profile; serum and pancreas oxidative stress (MDA) and endocrine and exocrine pancreas histology, estimating and rating inflammatory infiltrate, fibrosis, vacuolization and congestion in a semiquantitative score ranging from 0 (minimal) to 3 (severe and extensive damage). Results: Sitagliptin in diabetic ZDF rats promoted beneficial effects on dysglycaemia, dyslipidaemia, inflammatory profile and pancreatic oxidative stress. Endocrine and exocrine pancreas presented a reduction/amelioration of fibrosis severity, inflammatory infiltrate, intra-islet vacuolation, and congestion vs the vehicle-treated diabetic rats. Conclusions: The favourable biochemical profile promoted by sitagliptin in the diabetic rats, together with a protection against endocrine and exocrine pancreas lesions, might represent a further advantage of low doses of sitagliptin in the management of T2DM.
- Composting of different agro-food wastes: Effects of the phenolic and lignocellulosic fractions on greenhouse gases emissionsPublication . Santos, C.; Fonseca, J.; Coutinho, J.; Ferreira, L.; Pereira, J.; Trindade, H.Currently, society faces a number of challenges related to the large amounts of organic wastes generated and accumulated by the increasing expansion of agroindustrial activities1. Most of these wastes are rich in lignocellulosic compounds, which represents a major fraction of all plant biomass (of above 90%), so, its degradation is crucial for global carbon cycle2. These organic wastes may be introduced directly on agriculture sector as soil organic amendment, however, these might contain phytochemicals, such as phenolic compounds which may introduce toxic effects to soil and to beneficial organisms. Transformation and degradation of these renewable organic wastes into composts (COMPOSTING) is a possible solution for these problems and an environmentally friendly processes that allows make use of natural resources efficiently3. The main potential handicap is generation and emission of greenhouse gases such as carbon dioxide (CO2 ), methane (CH4 ) and nitrous oxide (N2O) and another ones which may led serious problems like nitric oxide (NO) and ammonia (NH3) 4. For this reason, quantification of GHG emissions from composting and finding possible relations with the chemical and structural composition of the wastes used is crucial to the development of technologies for mitigating emissions and should help to make decisions concerning waste management.
- Dairy cattle-slurry treatment technologies: towards an integrating approach of crop production, animal feeding and environmental impactsPublication . Rodrigues, A.; Gomes, A.; Ferreira, L.; Trindade, H.; Fonseca, A.; Pereira, J.Dairy cattle farms have a well-known environmental impact that affects all ecological compartments: air, soil, water and biosphere [1]. Dairy cattle farming are a significant source of anthropogenic gases from enteric fermentation, manure storage and land application, mainly ammonia (NH3), nitric oxide (NO), nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4). The emission of such gases represents not only an environmental problem but also leads to energy and nitrogen (N) losses in ruminant production systems [2-5]. Several efforts are required on the development of new technologies and strategies that mitigate gaseous emissions, N losses and improve the efficiency of the energy and N cycles [6, 7]. In the Northwest of Portugal, dairy cattle production has a major impact on the economy, with strong repercussions at national scale. Therefore, our Ph.D. thesis project aims to: a) Study natural supplements as additives in the dairy cattle diet towards a decrease in GHG emissions from feeding operations; b) Compare commercial dairy cattle diets with and without additives on gaseous emissions from manure deposited in a simulated concrete floor; c) Assess the concentrations and emissions of NH3 and greenhouse gases from commercial dairy cattle facilities; d) Evaluate the effects of different additives on lowering gaseous emissions from dairy cattle excreta, using a laboratory system simulating a dairy house concrete floor.