ABSTRACT
Seahorses are one of the most unique and enigmatic animals, recognized as flagship species for several conservation issues. Unfortunately, seahorses' populations have been declining and their unique lifestyle may constrain the ability of these animals to evolve in the future climate scenarios. They inhabit shallow coastal waters that display daily or seasonal environmental fluctuations. Yet, few studies have scrutinized the impacts of climate changes on these iconic species. Within this context, the objective of this work was to test the effects of an extreme hypoxia exposure (~27 % dissolved oxygen for approximately 7 h) on the metabolism, behaviour and food intake of the temperate seahorse Hippocampus hippocampus. Regarding metabolism, hypoxia exposure led to a significant reduction in metabolic rates and an increase in ventilation rates. Seahorses showed signs of movement lethargy under oxygen depletion. The results show that a small but extreme exposure to hypoxia is tolerable by seahorses despite inducing metabolic and behavioural changes, that may jeopardize the future development and survival of these iconic organisms.
Subject(s)
Smegmamorpha , Animals , Hypoxia/veterinaryABSTRACT
Fish fortification with iodine-rich macroalgae (Laminaria digitata) and Selenium-rich yeast is expected to promote nutritional added value of this crucial food item, contributing to a healthy and balanced diet for consumers. However, it is not known if steaming can affect these nutrient levels in fortified fish. The present study evaluates the effect of steaming on nutrients contents in fortified farmed gilthead seabream (Sparus aurata) and common carp (Cyprinus carpio). Fortified seabream presented enhanced I, Se and Fe contents, whereas fortified carp presented enhanced I, Se and Zn contents. Steaming resulted in increased I and Se contents in fortified seabream, and increased Fe and Zn levels in fortified carp, with higher elements true retention values (TRVs >90%). The consumption of 150 g of steamed fortified seabream contributes to a significant daily intake (DI) of I (up to 12%) and Se (up to >100%). On the other hand, steamed fortified carp contributes to 19-23% of I DI and 30%-71% of Se DI. These results demonstrate that steaming is a healthy cooking method, maintaining the enhanced nutritional quality of fortified fish. Moreover, the present fortification strategy is a promising solution to develop high-quality farmed fish products to overcome nutritional deficiencies.
Subject(s)
Cooking/methods , Food, Fortified/analysis , Iodine/analysis , Nutritive Value , Seafood/analysis , Selenium/analysis , Animals , Aquaculture , Carps , Hot Temperature , Sea Bream , Seaweed , Water/chemistry , YeastsABSTRACT
Developing tailor-made fortified farmed fish is a promising solution to overcome nutritional deficiencies and increase consumer confidence in these products. This study evaluated the supplementation of three fortified diets with I-rich seaweed and selenised-yeast on essential and toxic elements levels in gilthead seabream (Sparus aurata) and common carp (Cyprinus carpio). Fortified diets resulted in increased I, Se and Fe in fish muscle. Biofortified seabream and carp revealed lower Cu and Br. The reduction of fishmeal and fish oil in fortified diets resulted in lower Hg and Cd in seabream muscle. Contrarily, fortified diets increased As and Hg in carp fillets. The consumption of 150 g of fortified seabream enabled a significantly higher contribution to the daily recommended intake (DRI) of I (10%) and Se (76%) than non-fortified fish, whereas fortified carp fulfilled 23% of I DRI and 91% of Se DRI. Moreover, the exposure to Pb decreased with the consumption of biofortified seabream (23-82% BMDL01) and carp (26-92% BMDL01). These results support the strategy of developing eco-innovative biofortified farmed fish using sustainable, natural, safe and high-quality ingredients in feeds, to enable consumers to overcome nutritional deficiencies without significantly increased feed costs.
Subject(s)
Animal Feed , Carps , Dietary Supplements , Iodine/administration & dosage , Nutritive Value , Sea Bream , Selenium/administration & dosage , AnimalsABSTRACT
We investigated the effect of Alpinia zerumbet essential oil on the quality and shelf life of tambaqui (Colossoma macropomum) fillets stored under refrigeration (10.0 ± 0.5 °C) for 14 days. The treatments were A. zerumbet essential oil at 0.75% v v-1 (AEO 0.75%), A. zerumbet essential oil at 1.5% v v-1 (AEO 1.5%) and a control (no essential oil). The sample quality and shelf life were determined by the total psychrotrophic count (TPC) and chemical parameters (pH, total volatile basic nitrogen, centesimal composition and thiobarbituric acid reactive substances - TBARS) at zero, seven and 14 days of storage time. The TPC decreased significantly (p < 0.05) with an A. zerumbetessential oil level of 1.5% until seven days of storage. The concentration of A. zerumbet essential oil at 0.75% resulted in lower pH, TBARS, and TVBN values in comparison with the other treatment and the control. Thus, A. zerumbet essential oil was efficient in extending the shelf life of refrigerated tambaqui fillets up to approximately seven days. (AU)
Subject(s)
Quality Control , Oils, Volatile , Fisheries , AntioxidantsABSTRACT
Studies carried out with variation of protein concentration in the fish feed have shown an increase in the activity of alkaline proteases, acid proteases, trypsin and chimotrypsin from the digestive tract of silver catfish (Rhamdia quelen). These facts suggest that products released by digestion in the lumen of this tract can influenced the synthesis and secretion of digestive enzymes. The secretion of these enzymes by the pancreas in vertebrate responses to neural and humoral influences. In the present study, four concentration (0, 3, 6 and 12%) of an amino acid mix (threonine, phenylalanine, leucine, valine, arginine and thryptophan, in equal amounts) were tested in isocaloric (3500 Kcal of digestible energy/Kg of feed) and isoproteic (20% of protein) diets on juveniles of silver catfish. It was used 10 specimens per treatment stocked in a water recirculation system, with controlled and constant temperature. The fish submitted to the treatments presented alkaline activity in the anterior region of the gut, responding to the different levels of amino acid in the feed. Although there was alkaline proteases activity in the liver, the amylase activity of the liver and anterior gut was not observed.
Em estudos realizados com variação no teor de proteína na ração para peixes, foi demonstrado o aumento das atividades de protease alcalina, protease ácida, tripsina e quimiotripsina do trato digestório de jundiá (Rhamdia quelen). Esses fatos sugerem que produtos liberados pela digestão na luz desse trato podem influenciar a síntese e a secreção de enzimas digestivas. A secreção destas enzimas pelo pâncreas, em vertebrados, responde à influência neural e humoral. No presente trabalho, foram testadas quatro concentrações (0, 3, 6 e 12%) de uma mistura de aminoácidos (treonina, fenilalanina, leucina, valina, arginina e triptofano em iguais proporções) em dietas isocalóricas contendo 3.500 kcal de energia digestível kg-1 de ração, e dietas isoproteicas contendo 20% de proteína, em juvenis de jundiá. Foram utilizados dez animais por tratamento, sendo os peixes estocados num sistema fechado com recirculação de água e temperatura controlada. Os peixes submetidos a estes tratamentos apresentaram atividade da protease alcalina na região anterior do intestino, responsiva aos diferentes níveis aminoácidos da alimentação. Todavia, as atividades protease alcalina do fígado e amilase do fígado e intestino anterior não foram detectadas. Estes resultados sugerem que a atividade protease alcalina do intestino anterior seja induzida por aminoácidos liberados na luz do trato digestório.