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Animal ; 15(9): 100336, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34371468


Many of the studies in Campos grasslands focus on management aspects such as the control of herbage allowance, and application of nutrients and/or overseeding with legumes. However, there is little literature on how the Campos grassland resource is utilised, especially regarding the grazing pattern and the relationship between pasture quantity and quality on daily grazing activities. The study of the ingestive behaviour in species-rich and heterogeneous native grasslands during daylight hours, and understanding how animals prioritise quality or quantity of intake in relation to pasture attributes, are important to comprehend the ingestive-digestive processes modulating the energy intake of animals and to achieve a better grazing management. Therefore, the objective was to describe and quantify the daily grazing behaviour of growing cattle grazing native pasture with different structures as a result of different management practices, and study the relationship of pasture attributes and intake through multivariate analysis. The study was carried out at the Faculty of Agronomy, Paysandú, Uruguay. Treatments were native grassland, overseeding with Trifolium pratense and Lotus tenuis + phosphorus, and native pasture + nitrogen-phosphorus. Grazing activities were discriminated into grazing, searching (defined when animals take 1-2 bites in one feeding station and then change to another feeding station and so on), ruminating and idling. The probability of time allocated to each activity was continuously measured during daylight hours (0700-1930) and was related to pasture structure and forage quality using regression tree models, while the bite rate was determined every 2 h. The diurnal pattern of growing cattle showed grazing and searching sessions, followed by ruminating and idling sessions. The length of sessions (as the probability of time allocated to each activity) varied throughout the day. The grazing probability was greater during afternoon than morning and midday (0.74 vs 0.45 vs 0.46, respectively), and it was associated with higher bite rate (34.2 bites/min). Regression tree models showed different grazing, searching and ruminating strategies according to pasture attributes. During the morning, animals modified grazing, searching, ruminating and idling strategies according to bite rate, crude protein in diet and herbage allowance. At midday, they only adjusted ruminating and idling, while during afternoon sessions, grazing activities were modified by pasture quantity attributes such as herbage mass and herbage allowance. By controlling the herbage allowance, herbage mass and pasture height, animals prioritise quality in the morning and quantity in the afternoon, integrating and modifying the grazing-searching and ruminating-idling pattern.

Comportamento Alimentar , Pradaria , Ração Animal/análise , Animais , Bovinos , Dieta/veterinária , Ingestão de Alimentos , Feminino , Lactação
Nanoscale ; 7(15): 6527-33, 2015 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-25786779


In this work the selective uptake of native horse spleen ferritin and apoferritin loaded with MRI contrast agents has been assessed in human breast cancer cells (MCF-7 and MDA-MB-231). The higher expression of L-ferritin receptors (SCARA5) led to an enhanced uptake in MCF-7 as shown in T2 and T1 weighted MR images, respectively. The high efficiency of ferritin internalization in MCF-7 has been exploited for the simultaneous delivery of curcumin, a natural therapeutic molecule endowed with antineoplastic and anti-inflammatory action, and the MRI contrast agent Gd-HPDO3A. This theranostic system is able to treat selectively breast cancer cells over-expressing ferritin receptors. By entrapping in apoferritin both Gd-HPDO3A and curcumin, it was possible to deliver a therapeutic dose of 167 µg ml(-1) (as calculated by MRI) of this natural drug to MCF-7 cells, thus obtaining a significant reduction of cell proliferation.

Antineoplásicos/administração & dosagem , Neoplasias da Mama/tratamento farmacológico , Portadores de Fármacos , Proteínas de Ligação ao Ferro/química , Receptores de Superfície Celular/química , Ágar/química , Animais , Anti-Inflamatórios/química , Apoferritinas/química , Linhagem Celular Tumoral , Proliferação de Células , Meios de Contraste/química , Curcumina/química , Feminino , Ferritinas/química , Cavalos , Humanos , Células MCF-7 , Imageamento por Ressonância Magnética , Receptores Depuradores Classe A/metabolismo , Baço/metabolismo , Temperatura , Nanomedicina Teranóstica