One of the most critical steps in fish welfare occurs in the slaughter phase, with hormonal, biochemical, osmoregulatory and energetic alterations. These changes can affect the meat quality, with changes in colour and texture of the fillets, protein degradation, and lipid and metabolic oxidation (Daskalova et al.,2016;Zampacavallo et al., 2015).Various methods for stunning and killing fish have been studied, such as electrical current application, cranial percussion, hypothermia, asphyxiation, CO 2 narcosis, anaesthesia, and spiking. Among these methods, stunning by hypothermia has been one of the most used by the fish industry (Zampacavallo et al., 2015; Oliveira Filho, Oliveira, et al., 2015a; Oliveira Filho, 2015b). However, the rapid decline in the body temperature of fish can result in animal discomfort and delayed loss of consciousness Zampacavallo et al., 2015), increasing the plasma cortisol and catecholamines levels (Seth et al., 2013).CO 2 narcosis has various advantages, including the use of watersoluble gas, ease to apply and safe to handle (Rahmanifarah et al.,
AGRADECIMENTOSÀ Deus, por tudo... À minha orientadora, Profa. Dra. Mariza Pires de Melo, pela acolhida, paciência, empenho e dedicação; à minha co-orientadora Profa. Dra. Elyara Maria Pereira-daSilva, pela ajuda e acolhida e as duas por acreditar em mim além da amizade, Aos meus pais e irmã, que continuaram acreditando e me apoiando neste novo desafio, Ao Paulitico, meu namorado que acabou esposo no decorrer desta tese, obrigada pela compreensão e cumplicidade em todos os momentos, pela ajuda nas horas precisas e por torcer por mim e a sua e agora minha família, pelos bons momentos compartilhados, A família da minha saudosa amiga, Adriana A. Cuel Barone, Dri, agora minhas novas famílias, que tive a sorte de conquistar aqui em Pirassununga, Cuel -Assis - ABSTRACTThe aim of this study was to evaluate the hypothesis that the inclusion of lycopene in the commercial diet reduces the negative effects of stress and improves performance of juvenile Nile tilapia, Oreochromis niloticus. To this end was accomplished, first, a study that evaluated the effect of supplementation with lycopene (100, 200, 400 and 800 mg/kg of diet) on the attraction and palatability of the diet. In a second step, the effect of daily supplementation of lycopene (800 mg/kg of diet) for 60 days, to promote the welfare of juveniles subjected to restraint stress for 90 minutes.Zootechnical parameters were evaluated as weight gain, feed conversion, condition factor and specific growth rate, consumption and physiological and biochemical parameters as the plasma cortisol level, the content of lipid peroxidation, instrumental color of the fillet and the activity of antioxidant enzymes catalase (CAT) and glutathione reductase (GR) and activity of lactate dehydrogenase (LDH) in white muscle (fillet) and red muscle. The results were submitted to ANOVA and in case of significant effect between treatments, means were compared by Tukey test (p<0.05).The inclusion of lycopene did not affect the attraction and palatability of commercial feed in any of the concentrations studied. Supplementation with lycopene (800 mg/kg diet) did not alter any of the zootechnical parameters evaluated: weight gain, feed conversion, condition factor and specific growth rate. Likewise, did not alter the level of lipid peroxidation evaluated by thiobarbituric acid reactive substance (TBARS) and instrumental color of the fillet of fish. There was a reduction (34%) in catalase activity in white muscle of fish supplemented with lycopene, compared to the control group (no supplementation). However, catalase activity in red muscle was not altered by supplementation with lycopene, as well as GR activity and LDH in white muscle and red. It was demonstrated that restraint stress increased the plasma cortisol level (53%), level of lipid peroxidation of the fillet (28%) and activity of CAT, GR and LDH in white muscle (31%, 32% and 29%, respectively) and red muscle (48%, 46% and 44%, respectively) of animals subjected to stress. However, dietary supplementation with lycopene abolished the neg...
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