ESTUDIO PROTEÓMICO Y NEUROFISIOLÓGICO DEL ESTRÉS PSICOSOCIAL Y METABÓLICO EN UN MODELO PORCINO

Abstract

Animal welfare in the livestock industry is an issue of essential importance. Poor animal welfare can cause large economic losses due to low productivity, and low acceptance in the market for ethical issues and public opinion. Therefore, its study is imperative to reliably detect the welfare state of an animal._x000D_ When an animal manages to adapt to the adverse environment at the expense of a certain biological cost, it is considered to be subject to stress._x000D_ This work consists of three chapters focused on analyzing the effects of psychosocial stressors produced by the interaction with other individuals and the human-animal relationship, and metabolic stressors, specifically the nutritional stress due to overfeeding or food restriction and by intrauterine growth restriction (IUGR). The effects were studied by determining stress markers, neurotransmitters (NTs) and their metabolites in the brain and by proteomic approaches. The tissues were peripheral blood mononuclear cells (PBMC) and several brain areas._x000D_ The variation in hair cortisol levels and serum acute phase proteins suggests that these changes during the experimental period were mainly due to the decrease of stress by readaptation of the animals after mixing. Changes in the PBMC proteome reflects the consequences of the variation of endogenous cortisol and the degree of stress. However, handling treatments applied to the animals were not strong enough to provoke clear changes in porcine physiology. All results described in this study show a complex relationship between stress, animals management and immune cells._x000D_ Animals fed for 10 weeks with a High Fat Diet (HFD) presents changes in the concentration of hypothalamic neuropeptides involved in food intake and NTs in ventral hippocampus and hypothalamus, mainly from the dopaminergic pathway. While adding Bifidobacterium breve, omega-3 fatty acids or the combination of both in the HFD diet partially reverses the effects of the HFD diet on neuropeptides and NTs._x000D_ Reducing maternal diet to 70 % or overfeeding the mothers up to 130 % caloric intake, provoke alterations in the NTs profile in the hippocampus and hypothalamus of the piglets. On the other hand, treating these piglets with metformin, an anorexigenic signal is induced in the central nervous system (CNS) by changes in the NTs profile. In addition, the sympathetic nervous system is inhibited by reducing organism “fight and flight” response._x000D_ If maternal diet is reduced to 50 % from the first month of gestation, an IUGR effect occurs in the litter of piglets, which some individuals born with lower weight and asymmetric underdevelopment, which maintains a normal cranial size in detriment of the rest of the body (LBW). The IUGR effect specially alters in females and males the NTs of the dopaminergic pathway in the hippocampus, especially the degradation ratio of dopamine. Hippocampus of normal-weight female (NBW) piglets shows evidences of greater structural and neuronal development and metabolic activity than normal-weight males, according to the results of the proteomic analysis. However, stress produced by IUGR attenuates these differences in hippocampus structural and neuronal development between females and males. In addition, hippocampal female neurons affected by IUGR show evidences of greater resistance than male neurons to metabolic stressors such as lack of nutrients._x000D_ These studies reveal some of the mechanisms of response to psychosocial or metabolic stressors by immune cells and the central nervous system, increasing the knowledge about the underlying molecular mechanisms.

Date of Award	20 Jul 2018
Original language	Spanish
Supervisor	Anna Maria Bassols Teixido (Director)