The effect of dietary supplementation with calcium salts of long chain fatty acids and/or l-carnitine on ovarian activity of Rahmani ewes

摘要

This study investigated the effect of dietary supplementation with calcium salts of long chain fatty acids with or without of l-carnitine on ovarian activity using 24 Rahmani ewes randomly allocated to four treatments. Control animals (n =6) were fed a basal diet of hay (64.2%) and barley grain (35.0%) plus minerals and vitamins (0.8%). Ewes on the three treatments received the same basal diet supplemented with calcium salts of long chain fatty acids (CSFA) at 3% of the basal diet dry matter intake (1.4kg/ewe/d); 250ppm l-carnitine (LC); or both these supplements (CSFA+LC). All use exhibited natural estrus on one or two occasions and were weighed at the start and the end of the study as well as body condition score was assessed at the end of study. All ewes were then synchronised for estrus using intravaginal sponges for 12 d prior to the start of the nutritional treatments and three weeks after the nutritional treatments began. The nutritional treatments were imposed for a total of 8 weeks. Blood samples were collected prior to the start of treatments and every two weeks thereafter except after sponge removal of first and second synchronisation where the blood samples were collected daily for progesterone assay. The results revealed that Rahmani ewes received basal diet (control) and l-carnitine had significantly decrease final body weight and body condition score (36.3pl0.4; 36.8pl0.3; 2.2pl0.04; 2.1pl0.05; p <0.05, respectively) than those on CSFA and CSFA+LC (38.6pl0.9; 39.5pl0.6; 3.3pl0.07; 3.4pl0.06; respectively). At the second ultrasound examination, the control animals had significantly fewer total follicles (7.3pl0.8; p <0.05) than those on the CSFA (8.4pl0.8), l-carnitine (8.7pl1.5) and CSFA+LC (8.0pl0.6) treatments. The increased numbers occurred in the medium and large categories of follicles. In addition, the ovulation rates were significantly lower (p <0.05) for control (1.3pl0.2) and l-carnitine (1.5pl0.00) than for CSFA (2.5pl0.3) and CSFA+LC (2.3pl0.2). Furthermore, serum progesterone concentrations had risen and were significantly higher (p <0.05) for CSFA (2.5pl0.3ng/ml) and CSFA+LC (2.7pl0.1ng/ml) than for control (1.1pl0.7ng/ml) and l-carnitine (1.5pl0.4ng/ml). It was concluded that supplementation of the basal diet with l-carnitine alone did not improve performance of ewes or the ovarian response. However, the addition of calcium salts of long chain fatty acids to the basal diet alone or in combination with l-carnitine significantly improved the number and size of ovarian preovulatory follicles, and the ovulation rate of Rahmani ewes. Further evidence was required to study their influence on follicular atresia.