Open Veterinary Journal, (2025), Vol. 15(10): 5259-5265

Research Article

10.5455/OVJ.2025.v15.i10.42

Effect of vitamin E injection and seasonal changes on ram semen characteristics

Falah Abd-Allah Al-Asadi, Waleed Yousif Kassim^* and Hassan Nima Habib

Department of Animal Production, College of Agriculture, University of Basrah, Basrah, Iraq

*Corresponding Author: Waleed Yousif Kassim. Department of Animal Production, College of Agriculture, University of Basrah, Basrah, Iraq. Email: waleed.yosief [at] uobasrah.edu.iq

Submitted: 01/06/2025 Revised: 27/08/2025 Accepted: 06/09/2025 Published: 31/10/2025

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Abstract

Background: This study aimed to examine the effect of vitamin E injection and seasonal changes on semen characteristics (pH, ejaculation volume, mass motility, progressive motility, sperm concentration, live sperm, dead sperm, and abnormal sperm) in rams.

Aim: This study aimed to evaluate the effectiveness of vitamin E injections in improving semen characteristics in rams.

Methods: Twenty-one healthy rams were randomly divided into three groups (7 animals for each group) as follows: (1) control group injected with saline solution, (2) rams injected with 2 ml of vitamin E, and (3) rams injected with 4 ml of vitamin E. All doses were injected intramuscularly every 2 weeks during the cold season from December to the end of February 2022 and the hot season from June to the end of August 2023.

Results: The results showed significant (p < 0.05) differences between the treated groups in most of the semen characteristics. In summer, all of the semen characteristics were significantly increased (p < 0.05), except for the count of dead and abnormal sperm, compared with those in winter. Rams treated with 4 ml of E vitamin caused a significant increase (p < 0.05) in all semen characteristics, while this dose significantly decreased (p < 0.05) the percentage of dead and abnormal sperm in comparison with the control.

Conclusion: The study suggests that treating rams with 4 ml of vitamin E during the hot season could improve semen characteristics such as pH, ejaculation volume, mass motility, progressive motility, sperm concentrations, and live sperm.

Keywords: Vitamin E, Seasonal, Semen characteristics, Rams.

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Introduction

Many studies have indicated the role of vitamin E in increasing sexual desire and improving the characteristics and quality of semen in men (Al Rifaie et al., 2023). Seasonal factors (months of the year) may influence the sexual behavior of males through many factors, such as temperature, the rate of rain flow, lighting, available food, age, geographic location, humidity and rate and short generation period (Rosa and Bryant, 2003; Al-Ghalban et al., 2004; Farshad et al., 2012; Eman, 2019; and Ayyat et al., 2021). These factors play a role in stimulating or inhibiting sexual testosterone secretion, spermatogenesis, testicular size, and scrotal circumference (Zamiri and Khodaei, 2005; Kridli et al., 2007; Tajangookeh et al., 2007). Vitamins are organic compounds used in small doses. Vitamin E and selenium are powerful antioxidants that enhance animal immunity by protecting cells and tissues from oxidative damage caused by peroxides and free radicals. In addition, they play a significant role in boosting and improving fertility (Anita and Jacyno, 2005; Yue et al., 2010).

Furthermore, vitamin E plays an essential role in improving semen characteristics by improving sperm motility and increasing the concentration of sperm in the ejaculate, which leads to improved fertility rates in rams (Yousef et al., 2003). Vitamin E plays an important role in improving the characteristics of male semen in terms of maintaining sperm concentration, increasing and improving motility rates, maintaining sperm membranes, and balancing osmotic pressure within the sperm membrane (Ammar Bin et al., 2009; Soleimani et al., 2009; Mahmoud et al., 2013). Vitamin E and selenium (Se) are important nutrients that act synergistically and can affect several biological processes, including spermatogenesis and semen quality (Yousuf et al., 2003; Hussain et al., 2012). They also play a role in smooth and skeletal muscle movement by elevating the rates of Ca⁺⁺ and P absorption (Holick, 2006). In rabbits, Al-Rifaie et al. (2023) suggested that a diet supplemented with nutrients such as selenium and vitamin E can improve the health status of male rabbits and enhance the physical characteristics of their semen. Therefore, this study aimed to evaluate the effects of vitamin E injections during different seasons (winter and summer) on the characteristics of ram semen.

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Materials and Methods

This study was conducted in the animal field of the College of Agriculture at Basrah University from December to the end of February or 2022 (winter season) and from June to the end of August or 2023 (summer season) to study the effect of vitamin E injection on the fresh semen characteristics of rams during different months. Twenty-one healthy rams, aged (2.0–2.5) years old and weighing (45–50 kg body weight), were randomly divided into three groups (7 animals for each group) as follows: (1) the control group was injected with saline solution (0.9%); (2) the rams were injected with 2 ml of vitamin E (Tianjin Glory Technology Co., Ltd., China); and (3) the rams were injected with 4 ml of vitamin E intramuscularly every 2 weeks. All animals were housed in the semi-open yard and fed the same diet, which included 400 g/head of concentrate food (45% barley, 40% wheat bran, 10% yellow corn, and 5% fish meal). Additionally, they were grazed on natural pasture during the day (from 7:00 to 11:00 o`clock in the morning and from 3:00 to 6:00 o`clock in the evening), and clean water was preferred ad libitum. Table 1 shows the means of maximum and minimum temperatures in the months of the experiment.

Table 1. Mean of the maximum and minimum temperatures (°C).

Rams were trained to collect semen using an artificial vagina at the beginning of the experiment. When the exercise period ended, monthly semen collection was performed from all animals. Semen samples were placed in a plastic tube and covered with medical cotton to protect the samples from both the lighting and cold shocks. Semen pH, ejaculation volume, mass motility, progressive motility, sperm concentration, live sperm, dead sperm, and abnormal sperm were measured according to the method of Carrillo-González and Hernández (2016).

The obtained data were statistically analyzed using the general linear models within SPSS (2023). The study included two factors: the first factor was vitamin E with three levels, and the second factor was 6 months. The statistical analysis determined significant differences at the p < 0.05 level. The general statistical model was as follows:

y_ijk=µ + T_i. + M_j + TM_ij + e_ijk

where: y_ijk is the observation of the treatment within the month; µ, common mean; T_i. is the effect of the vitamin E levels [i=3, (0, 2, and 4 ml)]; M_j, the effect of the month (j=6 (January, February, June, July, August, and December); TM_ij, the effect of the interaction between treatment and months; and e_ijk, the experimental error, randomly and naturally distributed on all observations.

Ethical approval

All applicable national and international guidelines for animal care and use were followed.

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Results

Table 2 shows the effect of prolonged vitamin E injection on the pH of the ram semen. A noticeable increase (p < 0.05) in pH values was recorded during January and December in all groups compared to other months. However, lower values were observed in July, ranging from 7.07 to 6.55. The pH values decreased significantly (p < 0.05) when rams were injected with 4 and 2 ml of vitamin E compared with the control. The mean values were 7.54, 7.19, and 7.35. The pH of semen dropped in rams treated with 2 ml of vitamin E, particularly in July (7.00), while the highest levels were recorded in December (7.30) and January (7.35) in the control group. Vitamin E injections improved the pH values and brought them closer to neutrality, especially during the winter months.

Table 2. Effect of vitamin E injection on the pH and ejaculation volume of fresh semen from Arabi rams during different seasons.

The mean values of ejaculation volume, mass motility, and progressive motility were significantly different between months (Tables 2 and 3). These parameters were markedly higher in July, August, and June (summer) than in the winter. The ejaculation volumes of rams treated with two doses (4 and 2 ml) of vitamin E and the control group were 1.62, 1.25, and 1.38 ml, respectively, and 79.22%, 74.35%, and 69.11% to mass motility, respectively, and 80.74%, 75.56%, and 71.01% to progressive motility, respectively. Lower values of ejaculation volume (1 ml) were observed in December, January, and February, whereas the lowest values of both mass and progressive motility were recorded in February. There was no significant increase in the ejaculating volume of rams treated with 4 ml of vitamin E compared with rams treated with 2 ml of vitamin E. The mass and progressive motility increased significantly (p < 0.05) when the rams were injected with 4 ml of vitamin E compared with the control and rams treated with 2 ml of vitamin E. Furthermore, the increases in the trials above were clearer in July than in other months.

Table 4 shows that the sperm concentration increased significantly (p < 0.05) in February and August compared with other months. The lowest values were observed in January, which ranged between 2.03 and 1.85 × 10⁹/ ml. The interaction between vitamin treatment and the month of the year showed that injection of 4 ml of vitamin E into rams caused a decrease in sperm concentration, especially in January.

Table 3. Effect of vitamin E injection on mass and progressive motility (%) of fresh ram semen during different seasons.

Table 4. Effect of vitamin E injection on sperm concentration and live sperms of fresh ram semen during different seasons.

Tables 4 and 5 show the effects of vitamin E on live, dead, and abnormal sperm. The live sperm percentage increased significantly (p < 0.05) in August and July (86.46, 82.96, and 83.42, 82.50, and 81.66, 79.38) in rams treated with 4 and 2 ml of vitamin E and in the control group, respectively, compared with that in winter. The lowest values of live sperm in all groups were shown in February. The percentage of dead sperm decreased significantly (p < 0.05) during August and December (Table 5).

Table 5. Effect of vitamin E injection on dead and abnormal sperms (%) of the fresh semen of rams during different seasons.

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Discussion

Lower pH values were observed in July than in other months, probably as a result of the sharp thermal elevation in the Middle East region, which led to a decrease in scrotal sac activity and scrotal circumference. Consequently, sperm motility was limited due to a decrease in energy consumption. At this stage, the pH value was closer to the basic point. Additionally, in the summer and autumn (high temperature) months, the scrotal sacs spread and the circumference of the testes increases, which gives free space to increase sperm motility and subsequently increase energy consumption. At this stage, the pH value is closer to the acidic point (Bezerra et al., 2009). This result is compatible with those of Barkawi et al. (2006), Hussain et al. (2012), Oliveira et al. (2012), and on different breeds of rams and buck. Vitamin E maintains sperm motility at moderate levels during cold weather, thus preserving the energy reserve (fructose) and preventing it from being converted into lactic acid, lowering the pH values during winter. Conversely, vitamin E injections increased the speed of sperm motility, increased their consumption of fructose and lactic acid, and lowered the pH values during high temperatures (Tajangookeh et al., 2007). This result was in accordance with Moghaddam et al. (2012) and Morton et al., (2010) reports on different breeds of rams.

Lower values of ejaculation volume (1 ml) were observed in December, January, and February, whereas the lowest values of both mass and progressive motility were recorded in February. The concentration of testosterone increases in the summer, leading to improved mass and progressive motility. Mia et al. (2013), Mohamed et al. (2012), and Gündoğan (2007) reported that ejaculation volume, mass, and progressive motility in different breeds of sheep and goat males increase significantly in the hot months compared with the cold months.

The mass and progressive motility increased when the rams were injected with 4 ml of vitamin E compared with the control and rams treated with 2 ml of vitamin E. The increases in the trials above were clearer in July compared with other months. This could be due to the activation of Leydig cells by vitamin E for further releasing testosterone, which improves the production of plasma semen by accessory glands (Soleimani et al., 2009; Mahamoud et al., 2013). Additionally, vitamin E has an important role in reducing the antioxidants and peroxides that affect the energy supply for sperm motility (Yue et al., 2010).

The lowest sperm concentration values were observed in January, due to the variation in environmental conditions and their direct effect on spermatogenesis (Potemina, 2008). This result agrees with the results of Kridli et al. (2007) and Hussain et al. (2012). The interaction between vitamin treatment and the month of the year showed that injection of 4 ml of vitamin E into rams caused a decrease in sperm concentration, especially in January. Vitamin E is considered an antioxidant compound that prevents semen from oxidizing and peroxiding. Furthermore, vitamin E improves the levels of energy necessary for semen production from particular cells, which ultimately leads to an increase in the amount of sperm in the semen plasma (Yue et al., 2010; Hussain et al., 2012).

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Conclusion

This study concluded that the hot season could improve semen characteristics such as pH, ejaculation volume, mass motility, progressive motility, sperm concentrations, and live sperm. Therefore, we believe that summer and early autumn are the best seasons for breeding or collecting semen from local Arabian rams in the Basrah Governorate because of the abundance of green fodder and moderate light exposure, which improves their sexual behavior. Furthermore, to improve the same results in Arabian rams, a dose of 4 ml of vitamin E is considered the best. Therefore, more studies are necessary to investigate the effect of vitamin E on some production tracks, such as milk yield in females and wool growth in both females and males.

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Acknowledgments

The authors extend their sincere thanks to the Deanship of the College of Agriculture and Animal Husbandry at the College and the College of Veterinary Medicine for conducting the analysis in their laboratories. The authors also thank Dr. Sabah Kazim for conducting the statistical analysis of the research data.

Conflict of interest

The authors declare no conflict of interest.

Funding

The authors self-financed the research.

Authors' contributions

Falah Abd-Allah AL-Asadi1: administration and sample collection; Waleed Yousif Kassim: study design and laboratory work; Hassan Nima Habib: manuscript writing and revision.

Data availability

All data were provided in the manuscript.

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