Semen production capacity among boar breeds and effect of organic antioxidant supplementation on sperm characteristics during the hot season in Thailand

Abstract

The present study was carried out to investigate semen production capacity among boar breeds and measure the efficiency of a new organic antioxidant supplementation on semen production and qualities during the hot season in Thailand. A total of 711 ejaculates from 87 boars (i.e., 26 Duroc, 15 Landrace, 30 Yorkshire and 16 crossbred Landrace × Yorkshire) were included in the study. Semen samples were allocated into two treatments – without organic antioxidant (CONTROL; n = 397) and with organic antioxidant supplementation (TREATMENT; n = 314). The experiment was carried out for three months during the hot season in May (n = 184), June (n = 255) and July (n = 272). Semen volume (VOL), sperm concentration (CONC), total sperm production per ejaculate (TSP), subjective sperm motility (MOL), sperm head with abnormal morphology (AHM) and sperm tail with abnormal morphology (ATM) were evaluated. On average, there was a significant difference (P < 0.001) regarding VOL, TSP and MOL among the four breeds of boars, but no difference in the semen parameters compared between the two treatments (P > 0.05). Duroc semen volume was lower than Landrace, Yorkshire and Landrace × Yorkshire boars (177.7 ± 66.4 versus 222.1 ± 76.5, 230.0 ± 78.3 and 224.2 ± 73.5 ml, respectively, P < 0.05). Similarly, Duroc TSP was lower than Landrace, Yorkshire and Landrace × Yorkshire boars (65.1 ± 28.8 versus 87.5 ± 30.6, 81.6 ± 31.5 and 82.0 ± 33.6 × 109 sperm per ejaculate, respectively, P < 0.05). Across breeds, TSP of the semen collected in May was higher than those in June and July (86.5 ± 2.8 versus 78.3 ± 2.2 and 74.9 ± 2.0 × 109 sperm per ejaculate, respectively, P < 0.05). In conclusion, under a tropical climate, semen production of Duroc boars was inferior to other dam line breeds and the semen quality collected in June and July was lower than those collected in May. Supplementation of the current doses of the organic antioxidant cannot improve boar semen production during the hot season.