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Multiparous cycling, non-lactating Pelibuey ewes were used to determine the influence of calcium soaps of fatty acids (CSFA) in diets on serum concentrations of hormones and lipid metabolites. Eighteen ewes (n = 6 ewes per group) received 1 kg day−1 per ewe of isoenergetic and isonitrogenous diets containing 0% (C, control), 2.5% (M25) or 5% of CSFA (M50). Serum insulin (INS) was higher (P < 0.01) in ewes fed C (3.3 ± 0.1 ng ml−1) than ewes fed CSFA (2.7 ± 0.1 ng ml−1). Serum INS was greater (P < 0.001) in M25 (3.4 ng ml−1) than in M50 (2.1 ng ml−1). Serum concentrations of total cholesterol (CHOL; 85.7 ± 4.7, 110.1 ± 4.7 and 108.6 ± 4.7 mg dl−1 in C, M25 and M50, respectively) and high-density lipoprotein CHOL (28.1 ± 2.5, 34.3 ± 2.5 and 39.6 ± 2.5 mg dl−1 in C, M25, and M50, respectively) were higher in CSFA-fed ewes (P < 0.01). On day 9 of the estrous cycle, serum progesterone (P4) was lower (P = 0.07) in C (2.9 ± 0.36 ng ml−1) than in CSFA-fed ewes and higher (P < 0.01) in M25 (4.9 ± 0.36 ng ml−1) than in M50 (2.2 ± 0.36 ng ml−1). A similar tendency was observed in P4 on day 12 of the estrous cycle. Mean blood gonadotrophin (GnRH)-induced LH concentration on day 10 of the estrous cycle was greater (P < 0.001) in CSFA-fed ewes (24.7 ± 0.56, 25.3 ± 0.56 and 30.1 ± 0.56 ng ml−1 in C, M25 and M50, respectively) and it was affected by the CSFA level (P < 0.001). The area under the GnRH-induced LH curve was not affected by the diet (P = 0.22). Increased serum concentration of CHOL and HDL in ewes was associated with fed CSFA. Serum P4 and LH were higher in CSFA-fed ewes and they were affected by the level of CSFA used. Serum INS was lower in CSFA-supplemented ewes. |
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