Bioenergetic Pathways in the Sperm of an Under-Ice Spawning Fish, Burbot (Lota lota): The Role of Mitochondrial Respiration in a Varying Thermal Environment

Abstract

Regarding the sperm of cold-water fish, the contributions of different bioenergetic pathways, including mitochondrial respiration, to energy production at the spawning temperature and its adaptation at the maximum critical temperature (CTmax) are unclear. The roles of glycolysis, fatty acid oxidation, oxidative phosphorylation (OXPHOS) at 4 °C, and OXPHOS at 15 °C for energy production in burbot (Lota lota) spermatozoa were studied by motility and the oxygen consumption rate (OCR) (with and without pathway inhibitors and the OXPHOS uncoupler). At both temperatures, the effects of the inhibitors and the uncoupler on the motility duration, curvilinear velocity, and track linearity were insignificant; in addition, the OCRs in activation and non-activation media differed insignificantly and were not enhanced after uncoupler treatment. After inhibitor treatment in both media, OXPHOS was insignificantly different at the 2, 30, and 60 s time points at 4 °C but was reduced significantly at the 30 and 60 s time points after treatment with sodium azide at 15 °C. In conclusion, for burbot sperm at both the spawning temperature and the CTmax, the energy synthesized via OXPHOS during motility was insufficient. Therefore, the majority of the energy required to sustain motility was derived from pre-accumulated energy produced and stored during the quiescent state of the spermatozoa.

Impacts of global warming on fertility of male fishes: evidence from meta-analysis of temperature effects on spermatozoa motility

“…55 Also, VAP was available for Waigieu seaperch and gilthead seabream, showing negative effects of IWT. 31,56 Our meta-analysis suggests species-specificity to environmental temperature in terms of spermatozoa velocity, however a larger set of data is required for a clear conclusion. In this regard, Lahnsteiner and Caberlotto 31 reported no change in spermatozoa velocity of gilthead seabream within the temperature of 4 to 22 o C. Our meta-analysis showed no impacts of IWT on LIN (VSL/VCL) in both cold-water and warm-water species.…”

“…In total, 63 figures (including line charts and histograms) and six tables were extracted from these studies (Supplementary S2). The studies involved in the present review were Billard and Cosson (1992) 25,27,[30][31]35,[43][44][45][46][47][48][49][50][51][52][53][54][55][56][57] , For cold-water species, the overall effect size was 105 including k = 35 (for MOT), 11 (for DSM), 7 (for VCL), 8 (for VAP), 2 (for LIN), 20 (for EAES) and 22 (for ANEA). For warm-water species, the overall effect size was 112 including k = 32 (for MOT), 17 (for DSM), 17 (for VCL), 19 (for VSL), 3 (for VAP), 24 (for LIN) (Tables S1-S7).…”

Potential implications of sperm DNA methylation functional properties in aquaculture management

“…155,156 Also, energy required to maintain adequate ATP for spermatozoa motility in fish is generated through mitochondrial respiration. 157 Rahi et al 158 verified that most of the sperm energy was derived from stored ATP which was synthesized in a quiescent state but bioenergetically active state. The expression of Cyt b and Co I genes is associated with ATP production and spermatozoa motility in fish.…”