Small-scale environmental enrichment and exercise enhance learning and spatial memory of Carassius auratus, and increase cell proliferation in the telencephalon: an exploratory study

Abstract

Carassius auratus is a teleost fish that has been largely used in behavioral studies. However, little is known about potential environmental influences on its performance of learning and memory tasks. Here, we investigated this question in C. auratus , and searched for potential correlation between exercise and visuospatial enrichment with the total number of telencephalic glia and neurons. To that end, males and females were housed for 183 days in either an enriched (EE) or impoverished environment (IE) aquarium. EE contained toys, natural plants, and a 12-hour/day water stream for voluntary exercise, whereas the IE had none of the above. A third plus-maze aquarium was used for spatial and object recognition tests. Different visual clues in 2 of its 4 arms were used to guide fish to reach the criteria to complete the task. The test consisted of 30 sessions and was concluded when each animal performed three consecutive correct choices or seven alternated, each ten trials. Learning rates revealed significant differences between EE and IE fish. The optical fractionator was used to estimate the total number of telencephalic cells that were stained with cresyl violet. On average, the total number of cells in the subjects from EE was higher than those from subjects maintained in IE (P = 0.0202). We suggest that environmental enrichment significantly influenced goldfish spatial learning and memory abilities, and this may be associated with an increase in the total number of telencephalic cells.

Environmental enrichment increases the number of telencephalic but not tectal cells of angelfish (Pterophyllum scalare): an exploratory investigation using optical fractionator

“…Our findings are consistent with previous descriptions in both Danio rerio and C. auratus (von Krogh et al 2010;Abreu et al 2019) and showed the differential effects of environmental enrichment on the In contrast to endotherms, ectothermic animals exhibit cell proliferation due to nonspecific influences of the environment, such as changes in body temperature (Rieder and Cole 2002;Radmilovich et al 2003), sex (Perry and Grober 2003), age (Zikopoulos et al 2000;Traniello et al 2014), or somatic and neural injuries followed by regeneration (Ilieş et al 2014). Either in isolation or in combination these effects alter cell counts (Dunlap 2016).…”

“…Thus, we expect that the significant differences found between total telencephalic cell estimates in individuals maintained in environmentally enriched and impoverished aquaria are rather specific and associated with the contrasting environments. Although we did not investigate the subjacent mechanisms in the present study, we extended to P. scalare previous observations on telencephalic cell proliferation in the forebrain of zebrafish (von Krogh (Abreu et al 2019), demonstrating that the cell cycle in the telencephalon is also altered by environmental enrichment.…”

“…Although previous studies are not directly comparable, many of them investigated the influences of these two types of environment on neural mechanisms, especially in the cerebral cortex and the limbic system of mice (Kempermann et al 1997;Branchi et al 2006;Rossi et al 2006;Schloesser et al 2010), rats (Pham et al 2002), zebrafish (von Krogh et al 2010, Brachyhypopomus gauderio (Dunlap et al 2011), Oncorhynchus kisutch, Salmo salar (Lema et al 2005;Salvanes et al 2013) and C. auratus (Abreu et al 2019), demonstrating that the telencephalic cell cycle is influenced by environmental enrichment. From these analyses it has emerged that the sensory, motor and social stimuli of the enriched environment act on the brain by inducing plastic responses in the local and projection circuitry related to higher levels of neurotrophins and glial and neural plasticity, thereby increasing encephalic cellular proliferation in a variety of neurogenic niches (Pham et al 2002;Branchi et al 2006;Rossi et al 2006;Zhu et al 2006;Mora et al 2007;Angelucci et al 2009).…”

Environmental Enrichment Improved Learning and Memory, Increased Telencephalic Cell Proliferation, and Induced Differential Gene Expression in Colossoma macropomum

“…Although we did not investigate the subjacent mechanisms in the present report, we expanded our previous observations to C. auratus (Abreu et al, 2019), demonstrating that small-scale physical EE also alters cell cycling in the telencephalon of C. macropomum and that these changes coincide with enhanced performance on spatial learning and memory.…”

Medicinal Plants in Physical Exercise: A Review

“…The use of some types of supplements may be positive, on improving heavy training, relief of muscular pain, recovery of exercise lesion, changes of the physical structure, and mood improvement. Nevertheless, according to World Anti-Doping Agency (WADA) there are several substances, which are considered illegal, and that infringes the antidoping rule, such as peptide hormones, growth factors and related substances; beta-2 agonists; hormone and metabolic modulators; diuretics and masking agents [1][2][3].…”