Review: Mechanism, effectiveness, and the prospects of medicinal plants and their bioactive compounds in lowering ruminants' enteric methane emission.

Animal nutritionists continue to investigate new strategies to combat the challenge of methane emissions from ruminants. Medicinal plants (MPs) are known to be beneficial to animal health and exert functional roles in livestock due to their phytogenic compounds with antimicrobial, immunostimulatory, antioxidative, and anti-inflammatory activities. Some MP has been reported to be anti-methanogenic and can effectively lower ruminants' enteric methane emissions. This review overviews trends in MP utilization in ruminants, their bioactivity and their effectiveness in lowering enteric methane production. It highlights the MP regulatory mechanism and the gaps that must be critically addressed to improve its efficacy. MP could reduce enteric methane production by up to 8-50% by regulating the rumen fermentation pathway, directing hydrogen toward propionogenesis, and modifying rumen diversity, structure, and population of the methanogens and protozoa. Yet, factors such as palatability, extraction techniques, and economic implications must be further considered to exploit their potential fully.

[Leptin and hypothalamus-hypophysis-thyroid axis]. / Leptina ed asse ipotalamo-ipofisi-tiroide.

The leptin system is a major regulator of food intake and metabolic rate. The leptin, an adipose tissue hormone whose plasma levels reflect energy stores, plays an important rule in the pathogenesis of such eating disorders like bulimia and anorexia. Thyroid hormones are major regulators of energy homeostasis. It is possible that leptin and thyroid hormone exert their actions on thermogenesis and energy metabolism via the same common effector patways. Leptin influences feedback regulation of the hypotalamic TRH-secreting neurons by thyroid hormone. Low serum levels of thyroid hormones reflect a dysfunction of the hypotalamic-pituitary-thyroid (HPT) and hypotalamic-pituitary-adrenal (HPA) axis in patients with nervosa anorexia. Neuroendocrine effects of leptin include effects on the HPT and HPA axis. The aim of this work is to evaluated the interactions between leptina and HPT axis on the basis of recent published works and reviews in literature.

[Role of leptin in anorexia nervosa]. / Il ruolo della leptina nell'anoressia nervosa.

Anorexia and bulimia nervosa are the main psychiatric disorders characterised by abnormal models of feeding and perception of people's personal physical appearance and weight. These symptoms are associated with a severe psychosocial uneasiness that leads to severe medical complications and this, to its turn, has a big impact on morbidity and sick rate of general population. Although researchers have made big improvements in individualising some likely pathogenic mechanisms that include different factors (genetic, neurochemical and sociocultural) and psychological development, the pathogenesis of these kinds of feeding disorders is still unknown. Leptina is a neurochemical factor particularly relevant. It is a 17 KD hormone, produced by adipocytes. At hypothalamic level, it is essential for regulating body weight and body development. Recent studies have identified some factors responsible for the production and the secretion of leptina. They are micro and macronurishing factors, hormones and the sympatic neurotic system that is the most important among them. It plays a very important role for some disorders of feeding behaviour, specifically for the anorexia nervosa, where we notice a reduction of leptina levels strictly correlated to a reduction of the fat component. Since anorexia nervosa is associated to medical, nourishing and psychological components, it involves different areas and needs complete measurement and administration. Therefore the approach to this kind of pathology has necessarily to predict a multidisciplinary administration of patients. The aim of our work has been to point out the possible interactions between leptina and the development and progression of anorexia nervosa, on the basis of recent works and reviews in medical literature.