The primary function of spermatozoa is to fertilize the oocyte, which depends on their motility and is directly associated with their metabolic state. The oxygen consumption rate (OCR) of spermatozoa reflects the respiratory capacity of sperm mitochondria under various physiological conditions and is an essential marker of sperm quality. We determined the OCR of common carp (Cyprinus carpio) sperm using two respirometry methods: the conventionally used polarographic method with a Clark-type electrode and fluorometric assay with an Oxo Dish optochemical oxygen sensor. The latter was used for the first time to evaluate spermatozoa oxygen consumption in various metabolic states (under different treatments) at different dilution rates. These two methods were compared using Bland-Altman analysis, and the applicability of the optochemical oxygen sensor for evaluating carp sperm oxygen consumption was discussed. Sperm motility and progressive velocity parameters were also assessed to evaluate the effect of sperm respiration under different metabolic states and dilution rates and preincubation period on the physiological status of spermatozoa. The comparison of these respirometry methods clearly shows that while the polarographic method allows immediate measurement of oxygen levels after adding a sperm sample, the optochemical oxygen sensor has a priority in the amount of data obtained due to simultaneous measurements of several samples (e.g., different males, different fish species, repetitions of the same sample or various experimental conditions), even at a later time after adding sperm to the measuring chamber. However, the compared methods are complementary, and the proposed methodology can be applied to other fish species.

• Keywords
• Clark-type electrode, Common carp, Optochemical oxygen sensor, Oxygen consumption rate, Sperm motility, Spermatozoa,
• MeSH
• Cell Respiration physiology   MeSH
• Fluorometry * methods   veterinary   instrumentation   MeSH
• Carps * physiology   metabolism   MeSH
• Oxygen metabolism   MeSH
• Sperm Motility physiology   MeSH
• Polarography * methods   instrumentation   veterinary   MeSH
• Spermatozoa * physiology   MeSH
• Oxygen Consumption * physiology   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Oxygen MeSH

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.

• Keywords
• cold-water fish, fatty acid oxidation, glycolysis, maximum critical temperature, oxidative phosphorylation, spawning temperature, sperm motility,
• Publication type
• Journal Article MeSH

Influence of in vitro temperature on sperm antioxidant enzyme activity, thiobarbituric acid-reactive substance (TBARS) content and motility parameters was evaluated in sterlet Acipenser ruthenus and rainbow trout Oncorhynchus mykiss. Sperm activation was conducted at 4, 14 and 24 °C in both species. Duration of motility was significantly longer at 4 °C than at 14 and 24 °C in both species. At 60 s post-activation, the velocity of sterlet spermatozoa was highest at 24 °C. This trend continued to 420 s post-activation. In rainbow trout, at 10 s post-activation, the highest velocity was observed at 14 °C. Significantly higher catalase activity was seen at 4 °C in both species. No significant difference in spermatozoon superoxide dismutase activity among temperatures was observed. In sterlet, TBARS content was significantly higher at 24 °C compared to other temperatures, but, in rainbow trout, it was highest at 4 °C. The results presume species-specific level of antioxidant enzyme activity and TBARS content at studied temperatures.

• Keywords
• Antioxidant enzyme, Fish, Sperm function, Temperature,
• MeSH
• Antioxidants metabolism   MeSH
• Thiobarbituric Acid Reactive Substances metabolism   MeSH
• Sperm Motility * MeSH
• Oncorhynchus mykiss physiology   MeSH
• Lipid Peroxidation MeSH
• Fishes physiology   MeSH
• Spermatozoa enzymology   MeSH
• Superoxide Dismutase metabolism   MeSH
• Temperature * MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Antioxidants MeSH
• Thiobarbituric Acid Reactive Substances MeSH
• Superoxide Dismutase MeSH

Sexually mature males (BW = 1600 ± 150 g and TL = 235 ± 30 mm) of northern pike (Esox lucius L.) were randomly selected from a pond to record changes in their sperm quality parameters (spermatozoa morphology, sperm volume, density, and motility parameters) during the spawning season. The morphological and motility parameters changed significantly during the reproductive season with following trends. Only, head width was not changed during the spawning season. The longest spermatozoa and its flagellar length were found at the middle of spawning period (TL = 38.24 ± 0.37 μm and 35.14 ± 0.26 μm) and shortest at the beginning of spawning period (TL = 34.81 ± 0.29 μm and 32.53 ± 0.18 μm). Other morphological characters were always the lowest at the beginning of spawning period. Sperm volume was changed from 0.33 ± 0.3 ml in February, 0.43 ± 0.2 ml in March to 0.24 ± 0.1 ml in April, and density from 16.2 ± 0.2 × 109 spermatozoa ml-1 in February, 19.4 ± 0.2 × 109 spermatozoa ml-1 in March to 4.8 ± 0.2 × 109 spermatozoa ml-1 in April. Same sperm velocity was observed in all spawning terms at 10 and 20 s after activation. Higher velocity was found at 30 and 40 s after activation in sperm collected at the middle and the end of spawning period. Significantly, higher percentage of motile sperm was observed at 20, 30, and 40 s after activation in sperm sampled at the end of spawning period. This study supports the hypothesis that longer spermatozoa swim faster.

• Keywords
• Esox lucius L., Gamete, Male, Quality, Reproduction,
• MeSH
• Semen Analysis veterinary   MeSH
• Esocidae anatomy & histology   growth & development   physiology   MeSH
• Sperm Motility * MeSH
• Seasons MeSH
• Reproduction MeSH
• Sexual Behavior, Animal * MeSH
• Spermatogenesis * MeSH
• Spermatozoa physiology   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH