Tambaqui (Colossoma macropomum) is a native freshwater fish that is of great importance for Brazilian aquaculture. Because of this importance, several techniques have been developed to improve the reproduction of this species in captivity. One of these techniques is the cryopreservation of sperm. In an effort to increase the efficiency of cryopreservation protocols, researchers have tried to determine suitable diluting solutions and freezing methods, which will provide a better post-thaw sperm quality. Thus, this study aimed to evaluate the efficiency of different diluents and freezing methods for the cryopreservation of tambaqui (C. macropomum) sperm. Samples of fresh semen were diluted in different treatments (Glucose 5% + 10% Dimethyl sulfoxide -DMSO, Glucose 5% + 10% Methyl glycol -MG, BTS + 10% DMSO and BTS + 10% MG) at a 1:9 dilution rate and frozen in a programmed freezing machine and a dry shipper. The semen samples were thawed and evaluated for vitality, sperm morphology and kinetics. Cryopreserved semen with DMSO and using the programmed freezing machine provided a greater percentage of motile sperm (15.44 ± 1.04%) after thawing compared to the dry shipper (3.99 ± 0.55%), regardless of the diluent. Additionally, DMSO showed better sperm velocities than MG regardless of the freezing method and the extender employed. A higher percentage of living spermatozoa was observed when glucose (37.28 ± 1.32%) (regardless of the freezing method and cryoprotectant) and DMSO (37.98 ± 1.25%) was used in the programmed freezing machine. For morphology, a greater amount of normal spermatozoa (46.10 ± 1.82%) was observed when the semen was cryopreserved using a freezing machine programmed with DMSO as the cryoprotectant and Glucose or BTS (38.16 ± 1.9% and 39.26 ± 1.87%, respectively) as extenders. Therefore, we suggest the use of the DMSO (10%) cryoprotectant in association with the Glucose (5%) extended in the programmed freezing machine for cryopreservation of C. macropomum semen. ResumoO tambaqui (Colossoma macropomum) é uma espécie nativa de peixe de água doce de grande importância para aquicultura brasileira. Devido a isso, diversas técnicas têm sido desenvolvidas para aperfeiçoar a reprodução desta espécie em cativeiro, dentre elas a criopreservação de sêmen de peixe. Como uma forma de melhorar os protocolos de criopreservação, tem-se buscado utilizar soluções diluidoras e métodos de congelação adequados, proporcionando uma boa qualidade seminal pós-descongelação. Dessa forma, este estudo objetivou avaliar a eficiência de diferentes diluidores e métodos de congelação na criopreservação do sêmen de tambaqui (C. macropomum). As amostras de sêmen fresco foram diluídas em diferentes tratamentos (Glicose 5% + 10% Dimetilsufóxido -DMSO; Glicose 5% + 10% Metil glicol -MG; Beltsville Thawing Solution -BTS + 10% DMSO e BTS + 10% MG) na proporção 1:9 e congeladas em máquina de congelação programada e em Dry shipper. As amostras seminais foram descongeladas e avaliadas para vitalidade, morfologia e cinética espermát...

This study evaluated the effect of glucose or Beltsville Thawing Solution (BTS™) combined with dimethyl sulfoxide (DMSO) or methylglycol (MG) under two different freezing protocols on the kinetics and morphology of cryopreserved Prochilodus brevis sperm. The semen samples were diluted using one of four different treatments (glucose+DMSO, glucose+MG, BTS™+DMSO, and BTS™+MG), loaded into 0.25-ml straws and subjected to two different freezing processes (programmed freezing machine and dry shipper). After 10 days, the semen samples were thawed, and the sperm morphology and kinetics were evaluated. The physicochemical parameters of the semen in natura were similar to those observed in other studies of Characiformes, indicating the feasibility of semen cryopreservation. Glucose, when used as a diluent with the cryoprotectant MG (glucose+MG), yielded higher percentages of mobile spermatozoa after freezing in a dry shipper (76.88 ± 4.84%) and in a programmed freezing machine (70.95 ± 1.76%) compared with the combination of glucose and DMSO. Moreover, the glucose+MG treatment yielded a higher sperm velocity (curvilinear velocity: 79.52 ± 2.88 µm s -1 ; straight-line velocity: 45.46 ± 3.01 µm s -1 ; average path velocity: 67.92 ± 3.08 µm s -1 ) than the other studied treatments, and a higher amount of normal sperm (74.56 ± 0.77%) was observed in the semen samples cryopreserved using a programmed freezing machine. The sperm abnormalities observed included a bent tail morphology. Therefore, the use of glucose+MG in combination with either a dry shipper or a programmed freezing machine is recommended for the cryopreservation of P. brevis sperm because these methods yielded high numbers of motile and morphologically normal spermatozoa.

Resumo O objetivo deste trabalho foi avaliar o efeito da adição de gema de ovo (GO) sobre a cinética dos espermatozoides de tambaquis após a criopreservação. Utilizaram-se vinte machos de tambaquis (n= 4 pools), que foram induzidos hormonalmente com extrato hipofisário de carpa, para espermiação. Quatorze horas após a indução, realizou-se a coleta seminal. O sêmen de cada pool foi diluído em Ringer adicionado de 10% de dimetilsulfóxido (DMSO) acrescido ou não de GO (T1: sem acréscimo de GO; T2: com 5% de GO e T3: com 10% de GO). O sêmen tratado foi envasado em palhetas de 0,5 mL, congelado em vapor de nitrogênio líquido (dry shipper-30 min/-153 °C) e posteriormente transferidas para nitrogênio líquido. As palhetas foram descongeladas em banho-maria a 37 °C/30 segundos. A taxa de motilidade (%) e a velocidade curvilinear espermática (µm/s) foram analisadas em sistema computadorizado (CASA). Os dados foram expressos em média ± desvio padrão e foi aplicado o teste de Tukey (P<0,05). Houve uma redução significativa na porcentagem de espermatozoides móveis e velocidade curvilinear após a adição de GO independente da concentração. Logo, a adição de GO ao Ringer + DMSO teve efeito negativo sobre a motilidade do sêmen congelado de tambaqui.

, however, observed motility above 59% (59.8-67.8%), and low levels of spermatic abnormalities (19.3-19.5%) suggested that the ACP-104 can be used as a suitable medium for cryopreservation of common carp semen in any of the tested dilution ratios.

The objective was achieved by dividing the research into two experiments: (1) improving the freezing protocol using powdered coconut water (ACP-104) as a diluent for the cryopreservation seminal of common carp; (2) evaluating the effect of supplementation of vitamins C (ascorbic acid) or vitamin E (α-tocoferol) with the best extenders tested in experiment