EFFECTS OF CALCIUM SOAPS OF FATTY-ACIDS ON SERUM HORMONES AND LIPID METABOLITES IN PELIBUEY EWES

Multiparous cycling, non-lactating Pelibuey ewes were used to determin e the influence of calcium soaps of fatty acids (CSFA) in diets on ser um concentrations of hormones and lipid metabolites. Eighteen ewes (n= 6 ewes per group) received 1 kg day(-1) per ewe of isoenergetic and is onitrogenous diets containing 0% (C, control), 2.5% (M25) or 5% of CSF A (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 I NS 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, respect ively) and high-density lipoprotein CHOL (28.1 +/- 2.5, 34.3 +/- 2.5 a nd 39.6 +/- 2.5 mg dl(-1) in C, M25, and M50, respectively) were highe r in CSFA-fed ewes (P < 0.01). On day 9 of the estrous cycle, serum pr ogesterone (P-4) 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 P-4 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 concentratio n of CHOL and HDL in ewes was associated with fed CSFA. Serum P-4 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. (C) 1997 El sevier Science B.V.