T. L. Nedambale

24 RELATIONSHIP BETWEEN BOAR SPERM TRAITS AND FERTILITY RATE FOLLOWING ARTIFICIAL INSEMINATION UNDER SMALLHOLDER PRODUCTION SYSTEMS

The prediction of sperm fertility has a great economic importance to the pig breeding industry. The objective of the study was to determine the relationship between boar sperm quality and fertility following artificial insemination (AI) under smallholder production systems. A total of 18 ejaculates were collected from 3 breeding boars using a hand-gloved technique. Aliquots of diluted semen were assessed for sperm motility using a computer aided sperm analysis before AI. Sperm viability was evaluated using Synthetic Binding CD-14 (SYBR-14+)/propidium iodide (PI-), whereas sperm morphology was evaluated using Eosin Nigrosin staining. Fluorescent microscope was used at 100× magnification to count 200 sperm per slide. The semen was extended with Beltsville Thawing Solution and contained 3×109 sperm/dose. A total of 73 multiparous sows were inseminated twice. Fertility was measured by conception rate, farrowing rate, litter size and number of piglets born alive following AI. Sperm quality and fertility data were analysed using one-way ANOVA. Spearmans rank correlation was used to determine the relationship between sperm quality and fertility traits. The mean values for total sperm motility ranged from 93.5 to 96.8%. Progressive and rapid sperm motility differed significantly (P<0.05) among the boars. However, no significant differences were found for sperm velocity traits. The mean values for morphologically normal sperm ranged from 47.8 to 60.9% and live sperm ranged from 71.8 to 77.2%, but did not differ significantly among the boars (P>0.05). Conception rate from different boars varied (P<0.05) from 63.6 to 93.3%. Of all fertility traits studied, conception rate was significantly related to total sperm motility rate (r=0.34, P<0.0029), progressive motility (r=0.29, P<0.0141) and rapid motility (r=0.34, P<0.0032), although relatively low. There was a low positive relationship between morphologically normal sperm and fertility traits (P>0.05). In conclusion, total, progressive, and rapid sperm motility rate were the only sperm traits significantly related to conception rate. Conversely, litter size and number born alive were not correlated with sperm motility, viability, or morphology traits.

160 COMPARATIVE STUDY OF IN VITRO CULTURE MEDIA AND ASSISTED HATCHING TECHNIQUES ON MOUSE EMBRYOS

The in vitro culture media and assisted hatching techniques remain challenging obstacles to be utilised widely. Mechanical, chemical, enzymatic thinning, and laser-assisted techniques have been used previously but information is still lacking on its application in livestock. The aim of this study was to compare the effect of 2in vitro culture media (Hamster F10 and TMC-199) and 4 (mechanical, chemical, enzymatic, and laser) assisted hatching techniques on blastocyst formation and hatching rate using murine embryos as a model. The C57/b and Balb/c breeds were raised until they reached maturity and bred naturally to produce F1 generation. The light in the breeding house was controlled at 14h light and 10h dark. Feed and water were provided ad libitum for the mice. Superovulation of females were stimulated using equine chorionic gonadotropin and human chorionic gonadotropin. The F1 generation was used for the collection of the 400 blastocysts and randomly allocated into 4 assisted hatching techniques. Blastocysts were paired into a group of 10 and replicated 4 times for each assisted hatching technique. The general linear model of SAS version 9.4 (SAS Institute Inc., Cary, NC, USA) was used to analyse the data. Assisted hatching techniques of laser, mechanical, enzymatic, and chemical yielded 46.9±37.1, 51.1±40.2, 39.1±35.8, and 33.3±4.5%, respectively, under in vitro culture of Hamster F10. The TCM-199, laser, mechanical, enzymatic, and chemical assisted hatching techniques yielded 56.3±43.3, 52.6±35.5, 49.2±37.5, and 33.9±35.5%, respectively, with a significant difference. There was no significant difference observed in assisted hatching techniques and Hamster F10 culture medium. However, the hatching rate of embryos for all techniques was higher when in vitro cultured in TCM than cultured in Hamster F10. Hatching rate of blastocysts increased from chemical, enzymatic, mechanical, and laser with response to Hamster F10 and TCM; thus, laser is a suitable assisted hatching technique with TCM-199.

163 EVALUATION OF VIABILITY OF BULL SEMEN COLLECTED BY ELECTRO-EJACULATION USING COMMERCIAL SEMEN EXTENDER AND 2 CULTURE MEDIA AT CONTROLLED ROOM TEMPERATURE

Preservation of semen is an important process to ensure that semen quality is sufficient for assisted reproductive technologies. The aim of this study was to evaluate the viability of bull semen collected by electro-ejaculation using commercial semen extender and 2 modified culture media stored at controlled RT (24°C) for 72h. Two Nguni bulls were used for semen collection; after collection, the semen was evaluated macroscopically for volume, pH, and colour, and microscopically for sperm motility, viability, and morphology. Uncontaminated semen samples with progressive motility >70% and morphological defects <20% were pooled after collection before being aliquoted into 3 extenders, namely Triladyl, modified Hams F10, and TCM-199 culture media, at a dilution ratio of 1:4 and then stored at controlled RT (24°C). Sperm motility rate was analysed using the computer-aided sperm analyser after 0, 24, 48, and 72h of storage. Sperm morphology and viability was performed after staining the sperm cells with spermac and nigrosine-eosin stain, respectively. The study was replicated 4 times and data were analysed using ANOVA. Triladyl had a higher sperm viability rate (41.3%) and total motility rate (96.3%) for 72h (P<0.01) compared with the 2 modified culture media, Hams F10 (26.5 and 86.8%) and TCM-199 (25.0 and 86.7%), respectively. However, Hams F10 had higher progressive motility rate (37.8%) as compared with the other extenders, TCM-199 (31.7%) and Triladyl (23.4). There was no significant difference (P>0.05), in viability rate between Hams F10 (26.5%) and TCM-199 (25.0%). No significant difference (P>0.05) in straight line velocity was observed for the three extenders. Furthermore, no significant difference was observed in total sperm abnormalities, except for reacted acrosomes and absent tails (P>0.05), between the 2 Nguni bulls. Nguni semen can be preserved in Triladyl or modified Hams F10 and TCM-199 culture media stored at 24°C and stay viable for 72h. Triladyl proved to be the best suitable extender of the 3 extenders, showing higher sperm viability and total motility rate as compared with Hams F10 and TCM-199 modified culture media.