A cost or a benefit? Counterintuitive effects of diet quality and cadmium in Lymnaea stagnalis

Abstract

Diet quality can have a strong impact on organismal fitness although diet quality is infrequently considered as a factor in toxicity tests. The purpose of this study was to assess how diets differing in nutritional content affect sensitivity to Cd as measured by several sublethal responses related directly to bioenergetics. We evaluated feeding rate, growth rate, behavior and macronutrient content in the pond snail Lymnaea stagnalis exposed to Cd and fed two different diets. Hatchlings were fed either lettuce or high-caloric pellets, and exposed to 5, 10, and 20 µg/L Cd for 12 days. Length and weight were measured at the beginning and end of the test. The amount of food eaten and behavior were determined every two days. Total lipids, proteins and carbohydrates were biochemically measured at test end. For the second part of the study, snails were fed either lettuce or pellets for 2 weeks and then exposed to high challenge concentrations of Cd. Growth coefficients based on length and weight were significantly higher for snails fed pellets. In addition, snails exposed to Cd had significantly smaller growth coefficients than those in the control for both diets. Total carbohydrates and lipids were higher for snails fed pellets while the protein content was not significantly affected by Cd or diets. Even though snails fed pellets grew significantly faster, contrary to expectations they were significantly more sensitive to Cd compared to those fed lettuce. This study provides evidence that a bioenergetics-based approach can been used to better understand how diet can affect the ecotoxicity of chemical stressors to freshwater gastropods.

Parental diet affects embryogenesis of the great pond snail (Lymnaea stagnalis) exposed to cadmium, pyraclostrobin, and tributyltin

“…In the present study, the high‐calorie pellet and a combination of pellet and lettuce increased snail size (at least for the first 4 mo) compared to snails fed only lettuce. In a previous study (Reátegui‐Zirena et al ), L. stagnalis hatchlings fed pellets consumed as much as 3 times more food compared to snails fed lettuce, likely because the pellet was easier to ingest and assimilate. Herbivorous gastropods’ diet varies in cell wall toughness, palatability, nutritional value, and digestibility (Foster et al ); but more research is necessary before broad generalizations can be reached.…”

Diet quality affects chemical tolerance in the freshwater snail Lymnaea stagnalis

“…Many studies incorporate a single common and supposedly proven laboratory diet (e.g., studies following guidelines of the Organisation for Economic Co-operation and Development [OECD]); however, in nature animals rarely consume a single, specific food item throughout their lives (Madsen 1992;Zimmer et al 2012). More recently, Reategui-Zirena et al (2016) showed that the freshwater snail Lymnaea stagnalis was more sensitive to cadmium when fed a diet higher in nutritional content. Whereas diet quantity has been shown to alter chemical toxicity to a variety of aquatic organisms (Postma et al 1994), less is known regarding how differences in food quality impact toxicity.…”

“…This type of dietary simplification is common in ecotoxicology but does not reflect the energetic and nutritive variety that many species in nature likely face, which may lead to additional uncertainties in extrapolating from laboratory to the field. Despite the obvious effects of dietary composition on growth and other fitness traits in snails (and other organisms), there are few studies that have explored how differences in diet quality translate to differences in toxicant sensitivity (see Reategui-Zirena et al 2016). Snails raised on different diets have shown significant differences in overall growth (Kimberly and Salice 2012;Sandland and Minchella 2003;Dorgelo et al 1995), susceptibility to parasitic infections (Sandland and Minchella 2003), and transgenerational chemical sensitivity (Plautz et al 2013).…”

“…In one example, however, Daphnia magna fed different diets showed significant differences in overall chemical sensitivity (Enserink et al 1990). More recently, Reategui-Zirena et al (2016) showed that the freshwater snail Lymnaea stagnalis was more sensitive to cadmium when fed a diet higher in nutritional content. Given that resources vary and are influenced by a wide range of anthropogenic activities, understanding how nutritional environments influence ecotoxicological responses could prove valuable, especially as the field continues to develop mechanistic, bioenergetic-based frameworks and models for predicting ecological effects (Congdon et al 2001;Nisbet et al 2000).…”

“…Snails raised on different diets have shown significant differences in overall growth (Kimberly and Salice 2012;Sandland and Minchella 2003;Dorgelo et al 1995), susceptibility to parasitic infections (Sandland and Minchella 2003), and transgenerational chemical sensitivity (Plautz et al 2013). Despite the obvious effects of dietary composition on growth and other fitness traits in snails (and other organisms), there are few studies that have explored how differences in diet quality translate to differences in toxicant sensitivity (see Reategui-Zirena et al 2016).…”