Several semen characteristics were affected (P < 0.05) by week of collection (Table 2). For total sperm, there was a tendency (P = 0.06) for an effect of treatment week (Fig. 1). Other semen characteristics were not affected (P > 0.1) by treatment or treatment week.
Subsequent analysis revealed an effect (P = 0.02) of treatment period for total sperm cells; treatment with omega-3 fatty acids increased (P = 0.02) the total number of sperm from 84.3 2.3 109 (mean + S.E.M.) during Weeks 0–7 to 95.6 2.3 109 during Weeks 8–15. The total number of sperm in ejaculates of control boars was 86.3 2.3 109 during Weeks 0–7, and 86.4 + 2.3 109 during Weeks 8–15. Semen volume for Periods 1 and 2 was 280.9 and 260.4 mL, respectively for control boars and 276.9 and 275.5 mL, respectively for boars fed the diet supplemented with omega-3 fatty acids (S.E.M. = 8.7; treatment period, P = 0.28). Sperm concentrations for Periods 1 and 2 were 322.5 and 348.0 106 sperm/mL, respectively for controls, and 324.0 and 366.3 106 sperm/mL, respectively for supplemented boars (S.E.M. = 9.4; treatment period, P = 0.38).