RESUMO
BACKGROUND: Sulfated polysaccharides from the skin of Nile tilapia (Oreochromis niloticus), added to the tambaqui (Colossoma macropomum) semen diluting medium, can be potential antioxidants and promote the maintenance of sperm quality. OBJECTIVE: To evaluate the use of different concentrations of glycosaminoglycans (GAGs) from the skin of Nile tilapia as a supplement in two cryogenic media for tambaqui semen. MATERIALS AND METHODS: Tambaqui males received a single dose of pituitary carp extract. The semen was collected for pool analysis and, later, cryopreserved in liquid nitrogen. The pools were diluted and frozen in a solution containing fish-specific powdered coconut water (ACP-104) and 10% DMSO or 5% Glucose and 10% DMSO and supplemented with different concentrations of GAGs. The controls had no GAGs addition. After 45 days, the samples were thawed by immersion in a water bath and evaluated for membrane and DNA integrity, morphology and sperm kinetics. RESULTS: The parameters of linearity (LIN), straightness (STR) and DNA integrity of sperm frozen in 5% Glucose showed better results than ACP-104. For membrane integrity, concentrations of 0 and 1.0 mg/mL were better than 5 mg/mL. Semen motility in 5% Glucose showed superior results at concentrations lower than 5 mg/mL of GAGs. For VCL and VAP, in ACP-104, 3.0 mg/mL exceeded the other treatments. In 5% Glucose, for VCL, 4.0 mg/mL showed the lowest results compared to concentrations of <3.5 mg/mL and, for VAP, it also differed from 4.5 mg/mL CONCLUSION: Therefore, the skin of Nile tilapia has GAGs, in low concentrations, capable of improving the post-thawed sperm quality of tambaqui, especially in 5% Glucose medium.
