Seasonal Variations in Semen Quality, Testosterone Levels, and Scrotal Size following Dietary Flaxseed Oil and Ascorbic Acid in South African Indigenous Rams

Jabulani Nkululeko Ngcobo; Tshimangadzo Lucky Nedambale; Takalani Judas Mpofu; Khathutshelo Agree Nephawe; Tlou Caswell Chokoe; Fhulufhelo Vincent Ramukhithi

doi:10.3390/ani13071213

Seasonal Variations in Semen Quality, Testosterone Levels, and Scrotal Size following Dietary Flaxseed Oil and Ascorbic Acid in South African Indigenous Rams

Animals (Basel). 2023 Mar 30;13(7):1213. doi: 10.3390/ani13071213.

Authors

Jabulani Nkululeko Ngcobo^{1

2}, Tshimangadzo Lucky Nedambale^{1

2}, Takalani Judas Mpofu¹, Khathutshelo Agree Nephawe¹, Tlou Caswell Chokoe³, Fhulufhelo Vincent Ramukhithi^{1

2}

Affiliations

¹ Department of Animal Sciences, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa.
² Agricultural Research Council, Germplasm, Conservation, Reproductive Biotechnologies, Private Bag X02, Irene 0062, South Africa.
³ Department of Agriculture, Land Reform and Rural Development, Directorate Farm Animal Genetic Resource, Private Bag X250, Pretoria 0001, South Africa.

Abstract

The purpose of this study was to determine the seasonal variations in semen quality, testosterone levels, and scrotal size, following dietary flaxseed oil and ascorbic acid in South African indigenous rams. A total of 22 South African indigenous rams were randomly distributed into five treatment diets from June 2021 to May 2022 (12 months). To allow for the spermatogenesis period, semen was collected after sixty days of dietary supplementation with treatment diets. Blood was collected twice a week using an 18-gauge needle and vacutainer tubes and sent to the laboratory for testosterone analysis. Semen and blood collection were repeated eight times each season. The scrotal size (circumference, length, and width) was measured using a flexible measuring tape. Data was subjected to the General Linear Model (GLM) in Minitab^® 2017. Treatment means were separated using Fisher's t-test and considered significantly different when the p-value was less than 0.05. Seasons and diet had an effect on progression, total motility, and testosterone levels. For instance, NC during the spring season had the lowest progressive motility (42.84 ± 5.32), followed by the summer (49.38 ± 4.49), winter (62.46 ± 4.35), and autumn (63.26 ± 3.58). Notably, when treatment diets were introduced, improvements were realized, and there were significant differences (p < 0.05) among the seasons following supplementation of FLAX, ASCA, and FLAX + ASCA, except for FLAX in the autumn season (53.83 ± 4.16). Total motility did not differ significantly (p > 0.05) between the seasons when the NC and PC diets were supplemented; nevertheless, there was an improvement when FLAX, ASCA, and FLAX + ASCA were supplemented. Testosterone levels were significantly influenced by the seasons when negative and PC diets were supplemented. It is noteworthy that supplementing FLAX + ASCA can reverse the influence of the season on the testosterone levels (spring, 27.52 ± 4.42; summer, 20.23 ± 5.11; autumn, 25.24 ± 3.96; and winter, 25.92 ± 4.42). In conclusion, seasons do affect semen quality and testosterone levels of South African indigenous rams. However, flaxseed oil and ascorbic acid can reverse the seasonal variations in semen quality and testosterone levels.

Keywords: conservation; docosahexaenoic acid; fertility; omega n-3; semen quality.

Grants and funding

21.1.1/18/GR-02/API/Department of Agriculture, Land Reform and Rural Development