Extrativos vegetais com propriedades sedativas utilizados no transporte de jundiá (Rhamdia quelen)

Abstract

Management practices used in aquaculture are among the main stressful factors to fish and can cause adverse physiological reactions, affecting their essential functions. Due to the increasing use of anesthetics and sedatives on fish transport, it is important to analyze the effect of these agents in native fish, as well as standardization of alternative methods such as the use of plant extracts. Consequently this study evaluated the effectiveness of the use of eugenol (EUG), essential oil of Lippia alba (EOL) and methanolic extract of Condalia buxifolia (MECB) in the transport of silver catfish (Rhamdia quelen). In the first experiment fish (301.2 ± 21.4 g, 28.9 ± 1.3 cm, loading density 169.2 g L-¹) were transported for 4 h in plastic bags, divided into five treatments: control, EUG 1.5 or 3.0 μL L-¹ and EOL 10 or 20 μL L-¹. The analyzed parameters were acetylcholinesterase (AChE) activity (brain and muscle); non- enzymatic oxidative markers such as protein carbonyl content (PC) and formation of thiobarbituric acid reactive species (TBARS) and antioxidant activity of reduced glutathione (NPSH) and glutathione -S- transferase (GST) in the liver. In addition, general parameters related to metabolism were analyzed: glycogen, lactate and protein (liver and muscle). In the second experiment fish (420.1 ± 8.8 g, 21.2 ± 2.3 cm, loading density 275.1 g L-¹) were transported in plastic bags for 6 h, divided into five treatments: control, EOL 30 or 40 μL L-¹ and MECB 5 or 10 μL L-¹. In this experiment the ionorregulatory balance, water and blood parameters, activity of the enzymes AChE, NTPDase and 5'-nucleotidase (in the whole brain) and biochemical parameters such as: levels of NPSH, CAT, GST, GPx, SOD, ascorbic acid, TBARS and PC in liver, gill, muscle and kidney were evaluated. In these tissues, metabolic parameters were also evaluated. The results showed that, regardless of transport time (4 or 6 h), concentrations and extractives tested reduced biochemical activity in most tissues. There was oxidative stress in some tissues, but these variations do not indicate that these extractives are harmful to fish during transport. MECB was effective in reducing the ions loss and ammonia excretion. Therefore, based on these data it is recommended the use of EOL and MECB in the transport of silver catfish.