Determinacion del voltaje y el tamano del animal optimos para la extraccion de espermatoforos en el camaron de agua dulce Macrobrachium acanthurus

Abstract

RESUMEN.Hasta el momento los estudios sobre reproducción en Macrobrachium acanthurus están poco avanzados siendo importantes si se prevé la posibilidad de su cultivo. El objetivo de este trabajo fue identificar el voltaje más adecuado para la extracción de los espermatóforos y la menor talla con que estos langostinos los producen, como paso previo a desarrollar técnicas de fecundación in vitro. Se utilizaron voltajes de 4,5 y 6,0 voltios, realizándose el conteo de los espermatozoides en base a la supervivencia espermática en frotis coloreados con eosina-nigrosina. En el estudio de las tallas, los langostinos fueron separados en intervalos de clases y analizados en cuanto a la producción de espermatóforos y la supervivencia espermática. El mejor voltaje para la extracción del material seminal debido a menores mortalidades fue 6,0 voltios, a partir de 5 g de peso corporal y 18 mm de longitud de caparazón, cuando los langostinos pueden ser utilizados para la extracción de espermatóforos. Palabras clave: Macrobrachium acanthurus, Caridea, espermatozoides, reproducción, supervivencia espermática. Determination of adequate voltage and animal size for the extraction of spermatophores in the freshwater prawn Macrobrachium acanthurusABSTRACT. So far Macrobrachium acanthurus reproduction studies are poorly advanced being important if there is the possibility of cultivation. The aim of this study was to identify the most suitable voltage for the extraction of spermatophores and the smaller size at which these prawns produce them, as a prior step to develop in vitro fertilization techniques. Voltages of 4.5 and 6.0 were used, performing sperm count based on survival of sperm smears, colored with eosin-nigrosine. In the study of size, prawns were separated into class intervals and analyzed for production of spermatophore and sperm survival. The best voltage for the extraction of seminal material due to lower mortality was 6.0 volts and from 5 g of body weight, and 18 mm of length prawns could be used for the extraction of spermatophores.

Spermatophore production and sperm quality of the river prawn Macrobrachium americanum Spence Bate, 1868 fed with different diets

“…For example, spermatophore turnover of Penaeus setiferus (Linnaeus, 1767), Penaeus vannamei (Boone, 1931) and Penaeus stylirostris (Stimpson, 1871) occurs cyclically approximately every 15 days (Alfaro‐Montoya, ) and giant river prawn, M. rosenbergii, has a mean inter‐spermatophore production period that is considerably shorter (1–2 days) than that of M. americanum . This long inter‐spermatophore period can be explained because the M. americanum spermatophore is approximately five times heavier (10 mg, range = 3–47 mg) than the spermatophore of M. rosenbergii (2 mg) (Harris & Sandifer, ) and is almost ten times heavier than the spermatophore of Macrobrachium acanthurus (Wiegmann, 1836) (0.84 ± 0.47 mg), having an inter‐spermatophore period of 15 days (Viana da Costa et al, ).The decrease in spermatophore production (PSP%) observed during the present study implies a time limit for which M. americanum males can be used as broodstock prawns.…”

“…The spermatophores of M. americanum from the present study were extracted on average every 24 days (range 20–28 days) using an electro‐stimulation method with a 9 V battery (Sandifer et al, ). The sperm count and the record of the proportions of live/dead and normal/abnormal sperm morphology estimations were made by macerating the spermatophores in 0.5 ml of distilled water and staining the river prawn sperm with eosin‐nigrosin in 1.5 ml Eppendorf tubes (Viana da Costa et al, ). The sperm count was assessed using a Neubauer camera and observed with an optical microscope at 10, 20, 40 and 100× magnification (Leung‐Trujillo & Lawrence, ).…”

“…Sperm concentrations were reported as the number of sperm per microlitre (sperm/μl). The total number of sperm cells in each spermatophore and the proportion of dead sperm (DS%) and abnormal morphology sperm (AS%) were estimated according to Viana da Costa et al () as follows:where dS is the number of dead sperm observed in a sample and tS is the total number of live sperm plus dead sperm counted in a sample.where aS is the number of abnormal sperm cells in the Neubauer sample and tS is the total number of normal plus abnormal sperm counted in a sample. M. americanum normal sperm resemble an ‘inverted umbrella’ and have a long and straight spike, as was previously observed for M. rosenbergii (Poljaroen et al, ).…”

Sperm viability in wild-caught males of Macrobrachium tenellum (Smith, 1871) (Decapoda: Caridea: Palaemonidae) fed with different diets

“…Methods for evaluating sperm quality consist of determining the morphology, counting the number of sperm cells with the aid of optical microscopy, and the weight and regeneration of spermatophores (Coman et al, 2007;Leelatanawit et al, 2014;Harlıoğlu and Farhadi, 2017). The most widespread technique for spermatophore extraction in decapods is electrostimulation, since it is fast and can provide complete expulsions (Goldberg and Oshiro, 2000;Viana da Costa et al, 2016). This technique was first used in M. rosenbergii (see Harris and Sandifer, 1986), however, the use of electrostimulation may be a limiting factor for subsequent sperm extractions (Baskar et al, 2004), since there is evidence that it causes melanization of reproductive tissue (Harris and Sandifer, 1986).…”

“…These were carefully macerated using a glass tissue grinder to obtain complete release and homogenization of the sperm cells. Later, spermatic counts were performed using a Neubauer chamber (AmScope, model B020c, Irvine, CA, USA) (Viana da Costa et al, 2016). The percentage of dead sperm cells was determined through staining cells with Trypan blue (solution 0.1 %) (Ceballos-Vázquez et al, 2003).…”