Sperm characteristics of cryopreserved Prochilodus lineatus semen after adding cholesterol-loaded cyclodextrin

The experiment evaluated the effect of adding cholesterol-loaded cyclodextrin (CLC) to Prochilodus lineatus fish (Curimata) semen on post-thaw sperm quality. Twelve adult fish were used for sperm collection after induced spermiation with carp pituitary gland. The semen was diluted and treated with CLC in concentrations of 0 (control), 0.5, 1.0, 2.0, 3.0, and 4.0 mg for 120 × 106 spermatozoa/ml, loaded in 0.5 ml straws, packaged and placed in dry vapor vessel cylinders for 24 h before being submerged in liquid nitrogen for storage. The samples were thawed in a water bath at 60 °C for 8 s, and the sperm parameters evaluated were motility, activation duration, longevity, plasma membrane integrity, and morphology. Data were tested for normal distribution and ANOVA, followed by Friedman test (P < 0.05). Spermatozoa treated with CLC displayed higher motility than the control (P < 0.05). The duration of sperm activation was longer in sperm treated with 0.5, 1.0, and 2.0 mg of CLC than in control (P < 0.05). The membrane integrity was higher in sperm treated with 0.5, 1.0, 2.0, and 3.0 mg of CLC than in control and four mg-treated samples (P < 0.05). The sperm longevity and morphology alterations did not differ between treatments (P > 0.05). Adding 0.5, 1.0, or 2.0 mg of CLC in Prochilodus lineatus semen before cryopreservation improves sperm motility and membrane integrity.

Effect of Melatonin on Cryopreserved Sperm of Prochilodus lineatus (Characiformes)

BACKGROUND

Semen cryopreservation is a technique widely used in commercial and conservation fish farms. However, the success of the technique will depend on the diluent and cryoprotectant solutions added to the semen prior to the freezing procedure.

OBJECTIVE

To evaluate the effects of different doses of melatonin on motility, morphology and fertilization capacity of cryopreserved semen of Prochilodus lineatus.

MATERIALS AND METHODS

Semen was diluted in cryoprotectant solution with added melatonin, resulting in three treatments. A Control Solution (DMSO8% + BTS5%), was compared with T1, T2 and T3 treatments: BTS (5%) + DMSO (8%) plus concentrations of 1, 2 and 3 mM of melatonin, respectively. The diluted semen was frozen in a cylinder of vapour nitrogen and stored at -190°C. The straws were thawed in a water bath at 40°C for 12 s for analysis of sperm motility and morphology, and for evaluation of fertilization rate. The data were submitted to ANOVA, and the means were compared by the Tukey test.

RESULTS

There was no statistical difference (P>0.05) between the progressive motility rates and the velocities of the cryopreserved semen in the different treatments. The total motility rate was higher (P <0.05) in the groups T1 and T2 when compared to T3, but did not differ from control. All treatments had similar values of total anomalies after thawing and did not differ in fertilization capacity (P>0.05).

CONCLUSION

The addition of melatonin on the cryoprotectant solution did not promote changes on motility, morphology and fertilization capacity of cryopreserved semen of Prochilodus lineatus.

Reproductive biology of pequira Bryconamericus stramineus (Eigenmann, 1908) in Funil Reservoir-MG, Brazil

In order to evaluate aspects of reproductive biology of the "pequira" ( Bryconamericus stramineus) in the elevator of the Funil Dam - MG, fish capture was carried out from November 2008 to January 2009 and 317 individuals were collected. The mean standard length (SL) of the population was 4.96 cm and mean weight 1.80 g. The females had SL of 5.0 cm, while males had a SL of 4.6 cm. A sex ratio of 2.20: 1 (females: male) was observed. Our results show that 73% of the individuals analyzed were considered adults. The species presented low fecundity, mean of 470.9 oocytes per female and a mean diameter of 221.08 μm, with an increase in oocyte diameter over the evaluation period. The length of the first gonadal maturation was estimated at 5.0 cm. The results obtained in this work suggest that the reproductive cycle of the species occurs in the analyzed period. Although this species does not have migratory reproductive habits, the presence of adults in the reproductive stage was observed in the transposition area, which suggests a search for new environments for spawning.

Canonical correlation analysis to identify the semen characteristics used to forecast the freeze survival of Curimba (Prochilodus lineatus) spermatozoa

　　OBJECTIVE: To identify which sperm characteristics were able to predict more accurately the quality of curimba (Prochilodus lineatus) semen upon freezing using canonical correlation analysis.

METHODS

Eleven fish breeders with initial mean weight of 705.21 ± 111 g were used. For cryopreservation, 200 µL of semen were taken from each animal and diluted in the cryoprotectant solution (10% dimethyl sulfoxide and 5% Beltsville Thawing Solution Minitub) in a 1:4 ratio and placed into 0.5-mL straws. Sperm characteristics (motility, sperm abnormalities, total antioxidant activity and lipid peroxidation) were evaluated. A randomized block design with duplicate samples per treatment (fresh and frozen semen) was used. The block factor was the animals, and the experimental unit the ejaculates. Canonical correlation was used to evaluate the association between sperm characteristics of fresh semen and thawed semen.

RESULT

There was a significant association (P = 0.10) among the variables measured in fresh semen with the variables measured in thawed semen, and 78.6% of the difference observed in the thawed semen can be attributed to variation of variables measured in fresh semen. Sperm motility, motility duration and antioxidant activity of the thawed semen showed an inverse relationship with those of the fresh semen; whereas the minor sperm abnormalities, major sperm abnormalities and lipid peroxidation showed a direct relationship with those of the fresh semen. Only the rate and motility duration of the thawed semen presented high correlation (-0.63 and -0.73, respectively) with the canonical variable represented by the sperm characteristics of fresh semen.

CONCLUSIONS

The rate and motility duration of fresh semen may be used to predict the quality of the thawed sperm in Prochilodus lineatus.

Optimization of Artificial Propagation in Piracanjuba Fish Brycon orbignyanus Using Cryopreserved Semen

BACKGROUND: Cryopreserved semen could facilitate procedures during the artificial reproduction in fish. Factors affecting cryopreservation efficiency are important to define efficient protocols.

OBJECTIVE

This study investigated the application of cryoprotectants on the quality of piracanjuba fish semen, the sperm concentration required for oocyte fertilization and spermatic activation.

MATERIALS AND METHODS

We evaluated two intracellular cryoprotectant solutions (DMSO and methanol) and two extracellular cryoprotectant solutions (egg yolk and lactose) to cryopreserved piracanjuba semen. Sperm motility rate, motility duration and spermatic alterations were assessed.

CONCLUSION

The protocol for piracanjuba semen cryopreservation can use solutions including either DMSO or methanol as intracellular cryoprotectant and egg yolk or lactose as extracellular cryoprotectants.

Identificação do fator de crescimento semelhante à insulina i no plasma seminal de varrões e sua influência na qualidade espermática

A presente pesquisa foi realizada para investigar as relações entre os parâmetros dos espermatozóides e as concentrações de IGF-I no plasma seminal de varrões. Amostras de sêmen (duplicatas) foram coletadas de machos maduros (n=27). Em cada ejaculação, as características macroscópicas e microscópicas foram determinadas. Após a centrifugação para separar espermatozóides do plasma seminal, as concentrações de IGF-I em amostras de plasma seminal foram determinadas por kit de imunoensaio humano específico. A concentração média de IGF-I do plasma seminal de varrões foi de 1,5±0,2 ng/mL (n=54 amostras). Não houve correlação (p>0,05) entre IGF-I com a maioria dos parâmetros avaliados. Houve apenas uma correlação baixa negativa (-0,29, p=0,0331) entre a concentração de IGF-I no plasma seminal e a taxa de degradação da motilidade. Este estudo sugere que o IGF-I no plasma seminal de varrões não está relacionado com os parâmetros seminais iniciais do sêmen in natura. No entanto, o hormônio aumentou a duração da motilidade espermática.

Addition of IGF-I to storage-cooled boar semen and its effect on sperm quality

OBJECTIVE

To evaluate in vitro IGF-I treatment during warming of storage-cooled boar semen and its effect on seminal quality parameters and metabolism in spermatic cells.

DESIGN

Semen samples (n=7) warmed after stored at 15°C for 24 or 72h were divided into four equal parts. Different IGF-I concentrations (0, 50, 100 and 150ng/mL) were added to the semen samples. The samples were incubated at 37°C, and assessments were made after 0 and 120min of incubation.

RESULTS

For semen samples that were stored for 24h, the addition of IGF-I had no effect (p>0.05) on the total motility and intensity of movements by spermatic cells, osmotic resistance, live:dead cell ratio or total spermatic abnormalities. However, incubation with 150ng/mL IGF-I did decrease glutathione peroxidase activity (p<0.05) and reduce lipid peroxidation after 120min of incubation. For semen samples stored for 72h and incubated with IGF-I for 120min, there was a linear relationship between the IGF-I concentration and the live:dead ratio (p<0.05). There was a quadratic relationship between the IGF-I concentration and both the osmotic resistance (peak results at IGF-I=62.4ng/mL) and glutathione peroxidase activity (peak results at IGF-I=77.8ng/mL). There was no effect on lipid peroxidation (p>0.05) after 120min of incubation. Addition of IGF-I also decreased fructose utilization by spermatic cells regardless of semen storage time (p<0.05).

CONCLUSION

This study suggests that IGF-I may be beneficial to semen stored for longer periods of time. Adding 150ng/mL IGF-I improved the quality of semen stored for 24h, and adding 78ng/mL IGF-I improved the quality of semen stored for 72h.

Osmolaridade e taxa de diluição na ativação do sêmen criopreservado de Prochilodus lineatus

Objetivou-se avaliar a influência de ativadores com diferentes osmolaridades e taxa de diluição na ativação de sêmen criopreservado de curimba (Prochilodus lineatus). Foram utilizados quatro reprodutores machos capturados na Estação de Piscicultura da CEMIG, Itutinga, MG. As amostras de sêmen foram diluídas em duas soluções (DMSO + lactose e metanol + lactose) na proporção de 1:4 e congeladas. Foram avaliadas as taxas (%) e duração (s) da motilidade espermática dos tratamentos. Na ativação foram utilizados ativadores contendo as respectivas osmolarida-des: 30, 99, 183 e 293 mOsm nas taxas de diluição de 1:2, 1:4, 1:6, 1:8 sêmen: ativador. A taxa de diluição 1:2 e 1:8 foram estatisticamente significativas para duração da motilidade para o sêmen criopreservado com DMSO. Para a diluição 1:2, o sêmen ativado com o ativador contendo 30 mOsm, apresentou duração de motilidade maior em relação ao sêmen ativado com ativadores com 183 e 293 mOsm. No entanto, para a utilização do ativador com 30 mOsm, se obteve maior duração da motilidade na diluição de 1:2 em relação a diluição de 1:4. Na taxa de diluição 1:6, quando o sêmen foi ativado com o ativador de 30 mOsm, a taxa de motilidade foi superior à apresentada pelo sêmen que foi ativado com 293 mOsm. Na taxa de diluição de 1:8, o uso de ativador contendo 99 mOsm apresentou maior duração de motilidade em relação ao uso do ativador com 293 mOsm. Ativadores contendo altas osmolaridades podem proporcionar menores taxas e duração da motilidade em sêmen de curimba (Prochilodus lineatus) crio-preservado com os crioprotetores metanol ou DMSO.

232 OIL SOURCES AND VITAMIN E IN THE DIET ON THE BOAR SEMEN QUALITY PRESERVED AT 5°C

Spermatozoa experience physical and chemical stresses during cooling and freezing as a result of ice formation and osmotic changes in the medium. Sperm cryosurvival appears to depend on intrinsic properties of the sperm plasma membrane, such as biochemical composition, thermal behavior, osmotic resistance, and the physical stresses determined by the protocol. The objective of this study was to evaluate the addition of oil sources and dietary supplementation of the vitamin E on boar sperm characteristics cooled at 5°C. Twenty-four mature Dalboard 85 boars, of proven fertility and in routine semen production for artificial insemination, were randomly divided, in factorial arrangement 2 × 3, with 2 oil sources (35 g kg–1 of soybean or salmon oil were added to the basal diet as a supplement) and 3 levels of antioxidants (150, 300, and 450 vitamin E mg kg–1). The antioxidant used in this study was vitamin E provided as DL-α-tocopheryl acetate. At the start of the experiment, the age of the boars ranged from 1 to 2 years old. Sperm samples were collected after 0, 1a, 4a, 7a, and 10a weeks of feeding the experimental diets, and total motility, vigor, hypoosmotic swelling (HOST), sperm morphology, and the fatty acid composition of the sperm were determined. Ejaculates from each of 24 boars were diluted to 3 × 109 sperm to 80 mL in a Beltsville thawing solution diluent and cooled to 5°C in a bottle (3 bottles/boar were cooled). After 24, 48, and 72 h, sperm samples from 1 bottle/boar were analyzed. Treatment differences for sperm parameters were determined using ANOVA. Dietary supplementation with salmon oil reduced (P < 0.05) the proportion of ω6 fatty acid in fresh sperm, specifically of docosapentaenoic acid (22:5ω6), and it increased (P < 0.05) the proportion of docosahexanoic acid (22:6ω3). The motility and HOST of the animals sperm treated with salmon oil at 5°C was superior (P < 0.05) than animals treated with soybean oil, after 24, 48, and 72 h. Feeding salmon oil also increased (P < 0.05) sperm vigor after 24 and 48 h. The motility, vigor, and HOST of sperm at 5°C differed (P < 0.05) over the time they were preserved, with values at 24 h of storage being superior to sperm stored for 48 h and both being superior to sperm stored for 72 h. The percentages of sperm with abnormal morphology increased (P < 0.05) in the semen from animals treated with soybean oil. The percentages of sperm with abnormal morphology were higher (P < 0.05) in the semen at 5°C after 24, 48, and 72 h. Feeding boars salmon oil improved the sperm characteristics of boar semen cooled at 5°C during the 24 and 48 h of preservation time without using a specific diluent designed for this temperature. Supported by grants from: CNPq, FAPEMIG, Perdigao S/A., MINITUB, and Lagoa da Serra.

Crecimiento y supervivencia de postlarvas de Piracanjuba (Brycon orbignyanus)

Este trabajo fue desarrollado en el laboratorio de reproducción de peces de la Estación Ambiental de Itutinga, CEMIG, en enero de 2002. El objetivo fue evaluar el crecimiento y supervivencia de postlarvas de piracanjuba (Brycon orbignyanus), en diferentes densidades de siembra y frecuencias de alimentación. Las postlarvas fueron distribuidas en dieciocho cajas plásticas rectangulares con un volumen de 30 litros cada una. Todas las cajas con suministro y drenaje de agua individual, con renovación constante y temperatura del agua controlada (27oC), a través de un sistema de calentamiento. Los tratamientos experimentales consistieron en tres densidades de siembra (10, 20 e 30 postlarvas/litro) y dos frecuencias de alimentación (de tres en tres horas y de seis en seis horas). El diseño fue completamente al azar con tratamientos en esquema factorial 3 x 2 (densidad de siembra x frecuencia de alimentación) con tres repeticiones por tratamiento. Los resultados mostraron que el aumento de la densidad de siembra reduce linealmente la supervivencia de los peces. Se registró una diferencia significativa (p0,05). De acuerdo con los resultados, se concluye que la mejor supervivencia se obtiene con la densidad de 10 postlarvas/litro de piracanjuba, alimentadas de tres en tres horas.

Estudo comparativo de diferentes técnicas de avaliação da concentração espermática em suínos

A determinação precisa e acurada da concentração espermática do ejaculado suíno é importante na produção de doses inseminantes com um número determinado de espermatozóides. O objetivo do trabalho foi comparar a eficiência de algumas técnicas de mensuração da concentração espermática no sêmen e determinar equações de predição, estabelecendo uma correlação entre elas. Foram coletados 93 ejaculados que tiveram as concentrações espermáticas determinadas de forma direta (câmara de Neubauer, CN) ou indireta (espermiodensímetro, ED e espectrofotômetro, EF). Foi utilizado um delineamento em blocos casualizados, com 93 repetições e duas análises por parcela experimental. Os valores foram submetidos à análise de variância, as médias submetidas ao teste SNK e os tratamentos interrelacionados pelo ajuste do modelo linear entre os dados (equações de predição). Não houve diferença na determinação da concentração espermática obtida com ED (361,7 x 106 sptz/ml) e EF (343,7 x 106 sptz/ml), porém estes valores foram maiores com relação a CN (245,3 x 106 sptz/ml). As equações obtidas foram: ED= -0,30 [volume (em ml)] + 0,61 EF + 213,47 (R2= 0,72) e ED= -0,50 [volume (ml)] + 0,47 CN (R2= 0,7). As técnicas de mensuração da concentração espermática pelo ED e EF superestimam os valores em relação à CN. Novos estudos devem ser conduzidos para determinar a verdadeira eficiência com que essas técnicas são empregadas a campo.