EFICIí­Å NCIA DE ANESTÉSICOS EM Fí­Å MEAS DO GASTRÓPODE Littoraria angulifera

Abstract

The present study evaluated the effect of three anesthetics at three concentrations, menthol (C10H20O) (1%, 1.5%, 2%), eugenol (C10H12O2) (0.5%, 1%, 1.5%) and magnesium chloride (MgCl2) (4%, 7%, 10%) diluted in distilled water on the gastropod Littoraria angulifera. Twenty females were tested for each concentration with shell height varying between 18.3 and 26.1 mm (n = 180), all collected from the same site. The time of induction and recovery of the sedative effect, as well as the survival rate, were assessed. The animals were kept within aquaria at a temperature of 25±1°C and observations were made every 30 minutes since the beginning of the anesthesia for up to 2 hours. After this period, the animals were kept in aquaria and observed during the following 15 days for survival evaluation. Only MgCl2 caused a sedative effect on L. angulifera. At 4% and 7% MgCl2 solutions, 20% and 95% of animals were anesthetized after 2 hours, respectively, and at 10% all animals were anesthetized after 1 hour. In conclusion, L. angulifera can be efficiently anesthetized in a 10% MgCl2 solution for 1 h and the recovery occurs in 30 minutes with no apparent side effects on behavior and survival.

Morphometric analysis of Littoraria angulifera (Caenogastropoda) in estuarine regions of northeastern Brazil

“…In relation to the use of the morphometric parameters (prostate length and distance between the opening of the prostate to the anus in males; oviduct length and distance between the vulva to the anus in females), although until the present study, this morphometry has not been used for L. angulifera, morphophysiological changes in the reproductive system, to the detriment of organotin contamination, were observed in Europe by Bauer et al (1995) in Littorina littorea (L.), an oviparous species, which reported a gradual replacement of the oviduct by a prostate, and in the latter stage there may be the development of a penis and a seminal sulcus, with sterilization of the female called intersex. Zeidan et al (2018) confirmed that morphometric changes occurred in the gonads of L. angulifera females submitted to injections and feed contaminated with tributyltin, which presented palial oviduct more elongated than the negative control, indicating masculinization and possibly impairment of larval release to the environment.…”

“…The processing was done at the Laboratory of Marine Mollusks (LMM / UESC, Ilhéus, Brazil) and complemented at the Laboratory of Estuarine Marine Ecology (LEME, University of Aveiro, Portugal). After the macroscopic shell analysis of color and texture, the specimens were measured in relation to the main axis (height), using a digital caliper with 0.01 mm precision and anesthetized with 10% Magnesium Chloride (MgCl 2 ) in distilled water for 1 hour, following the recommendation of Zeidan et al (2018). The shell was broken with a table vise for sex observation and analyzes of the reproductive tract.…”

“…Nevertheless, few studies have used it as a sentinel species of environmental quality in mangroves/ estuaries (Martínez et al, 2013). Recent studies in Southeast (Costa et al, 2013) and Northeast Brazilian coast (Zeidan et al, 2018), suggest the feasibility of using L. angulifera as bioindicator for organotin contamination that still been used in antifouling paints of boats.…”

Population attributes of Littoraria angulifera (Gastropoda: Littorinidae) in mangroves in Bahia State, northeastern Brazil

“…The study was conducted in two mangroves located in the municipalities of Ilhéus (14°88'33.38"S;39°02'06.45"W) and Uruçuca (14°34'26.25"S;39°3'8.20"W), in southern Bahia (northeastern Brazil), in the study denominated (Lots A and B); (ii) anesthesia with 10% Magnesium Chloride (MgCl 2 ) in distilled water (Lots A and B), a procedure that does not cause damage or death to the animal, but which facilitates the handling of specimens (Zeidan et al, 2018); (iii) weighing with shell on scale (Marte, with precision of 0.001g) (Lot A) and (iv) sexing (Lot A), with the naked eye, using the presence/absence of the penis as a visual parameter.…”