Liquid storage of Ostrich (Struthio camelus) semen at 5 °C through intermediate dilution.

Dilution rate, dilution temperature and storage time have been recognized as vital steps in the processing of semen for storage before artificial insemination. The objective of this study was to determine optimal dilution and dilution temperature with an ostrich-specific semen extender for chilled storage. Four preselected ostrich (Struthio camelus var. domesticus) males, known for their ease of collection and specific semen quality parameters, were collected using the "dummy" female method. Dilution of 384 semen samples, at rates of 1:1, 1:2, 1:4 and 1:8 semen/diluent ratio with a diluent set at 5, 21 and 38 °C was performed and stored for 48 h at 5 °C. In vitro sperm function tests were conducted to evaluate treated semen during different storage intervals of 1, 5, 24 and 48 h. Motility and kinematic parameters were measured by the Sperm Class Analyzer®, the percentage live sperm measured by fluorescence SYBR14®/PI (LIVE/DEAD®), the percentage of sperm able to resist the hypo-osmotic swelling (HOS) stress test and sperm morphology determined by Nigrosin-Eosin staining. Progressive motility (PMOT), motility (MOT), sperm kinematics, LIVE and HOS were best (P < 0.05) maintained at a higher dilution of 1:4-1:8. The beneficial effect (P < 0.05) of a higher dilution temperature (21 °C) was prominent in terms of PMOT at a higher dilution. Storage of chilled semen at 5 °C requires dilution, at interpolated rates of 1:6-1:7, together with an extender temperature of 21 °C, to maintain optimal sperm function with minimal loss over a 48 h storage period.

Mineral profiling of ostrich (Struthio camelus) seminal plasma and its relationship with semen traits and collection day.

Successful assisted reproduction techniques, with specific focus on in vitro semen storage for artificial insemination, are dependent on certain key elements which includes the biochemical profiling of semen. The objective of this study was to complete an ostrich seminal plasma (SP) evaluation by inductively coupled plasma mass spectrometry (ICP-MS) among seven males at different daily intervals (day 1, 3, 7, 11, 15, 19, 21, 23, 25, 26, 27, 28) for a period of 28 days during spring (August to September) for mineral profiling. The effect of collection day and male on sperm concentration, semen volume and seminal plasma volume, was explored as well as the relationships amongst these specific sperm traits and SP minerals. Variation amongst SP mineral concentrations, accounted for by the fixed effects of sperm concentration, semen volume, seminal plasma volume, collection day and male, ranged from 18% to 77%. Male had the largest effect on variation in SP minerals, namely: phosphorus (P), potassium (K), calcium (Ca), sodium (Na), boron (B), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), molybdenum (Mo), barium (Ba), arsenic (As) and selenium (Se). Sperm concentration instigated fluctuations of P, magnesium (Mg), B, zinc (Zn), Fe, aluminium (Al), Se, manganese (Mn) and lead (Pb). Semen volume had an effect on Na, K, B, Pb and Ba while seminal plasma volume only influenced variation in Na. There were fluctuations among collection days of specific micro minerals, Ni and Mo, with initial Ni concentrations being relatively greater and Mo at lesser concentrations. Semen volume, seminal plasma volume and sperm concentration varied amongst males. Sperm concentrations during the initial collection days, 1 and 3, were less than that for days 7 to 28. Significant variation of SP minerals and sperm characteristics among ejaculates and males suggest an association of these specific elements with sperm function and are, therefore, considered to be of potential importance to success of assisted reproduction technology for the ostrich. The relationship amongst sperm concentration and collection day confirms the need to conduct an initial period of collection to stabilise a greater sperm concentration to optimise sperm numbers for artificial insemination purposes.

Ostrich specific semen diluent and sperm motility characteristics during in vitro storage.

The dilution of semen is a very important initial process for semen processing and evaluation, storage and preservation in vitro and efficient artificial insemination. The aim of the study was to evaluate the effect of two synthetic diluents (OS1 and OS2) on ostrich sperm motility parameters during in vitro storage. Formulation of OS1 was based on macro minerals (Na, K, P, Ca, Mg) and OS2 on the further addition of micro minerals (Se and Zn), based on mineral concentration determined in the ostrich seminal plasma (SP). Sperm motility was evaluated at different processing stages (neat, after dilution, during storage and after storage) by measuring several sperm motility variables using the Sperm Class Analyzer® (SCA). Processing (dilution, cooling and storage) of semen for in vitro storage purposes decreased the values for all sperm motility variables measured. The percentage motile (MOT) and progressive motile (PMOT) sperm decreased 20% to 30% during 24 h of storage, independent of diluent type. Quality of sperm swim (LIN, STR and WOB), however, was sustained during the longer storage periods (48 h) with the OS2 diluent modified with Se and Zn additions. Quality of sperm swim with use of OS1 was 6% to 8% less for the LIN, STR, and WOB variables. Male fitted as a fixed effect accounted for >60% of the variation for certain sperm motility variables (PMOT, MOT, VCL, VSL, VAP and ALH) evaluated at different processing stages. Semen from specific males had sustained sperm motility characteristics to a greater extent than that of other males during the 24-h storage period.

Classification of ostrich sperm characteristics.

The success of assisted reproduction techniques is dependent on a sound foundation of understanding sperm characteristics to evaluate so as to improve semen processing. This study offers a descriptive basis for ostrich semen quality in terms of sperm function characteristics (SFC) that include motility, measured by computer assisted sperm analysis CASA (SCA(®)), viability (SYBR14/PI) and membrane integrity (hypo-osmotic swelling test). Relationships among these SFC's were explored and described by correlations and regressions. Certain fixed effects including the dilution of semen, season, year and male associated with semen collection were interpreted for future applications. The seasonal effect on sperm samples collected throughout the year suggested that it is prudent to restrict collections to spring and summer when SFC's and sperm concentration are maximized, compared to winter when these aspects of sperm quality are suppressed. Dilution of ejaculates helped to maintain important SFC's associated with fertilization success. The SFC's and sperm concentration varied among males, with specific males, having greater values for the percentage of motile (MOT) and progressively motile (PMOT) sperm, as well as sperm velocity (VCL, VSL, VAP) and linearity (LIN) variables. Males may thus be screened on these variables for inclusion in an artificial insemination (AI) programme to optimize fertility success rates.