Follicular dynamics and production of oocytes in young Nellore heifers with energetic supplementation

Abstract

-To verify the effects of energy supplementation and fat on follicular dynamics, metabolic profile and the production of oocytes, 15 young heifers (Bos taurus indicus) with an average age of 14 months and with an initial weight of 256.35 kg were assigned to two treatments according to weight and follicular population as evaluated by ultrasonography: in T1 (1.0 × M), animals received 100% of the energy requirements for maintenance; in T2 (1.7 × M), animals received 170% of the energy requirements for maintenance, achieved by the addition of 200 g of Megalac ® . After a period of adaptation to the diet, the treatments, blood collection and follicular aspirations were started using a randomized design. The dry matter intake and weight gain were lower in the 1.0 × M group than in the 1.7 × M group. No differences were found in the plasma progesterone concentrations, albumin, glucose, urea or gonadotropin (FSH and LH) levels between the groups. The mean concentrations of cholesterol were higher in the 1.7 × M group. The total number of small (<4 mm) and medium follicles (4-8 mm) was not altered by the treatments, but the number of small follicles increased on days 1 and 2 of the estrous cycle, with higher values found in the 1.7 × M group. The average of the oocytes also increased (9.50±2.1 and 12.5±4.4 for the 1.0 × M and 1.7 × M groups, respectively). The rapid increase in the amount of energy offered in the diet changes the amount of follicles and oocytes available for follicular aspiration (OPU) in young heifers without changing their metabolic profile.

Effects of different supplemental soya bean oil levels on the performance of prepubertal Saanen goats: Oestrogen and progesterone release

“…In general, a high level of urea decreases the number of viable follicles and reduces the fertility of ruminants (Leroy et al., ; Ferreira et al., ; Ying et al., ). In contrast, other authors have associated the inclusion of fat in the ruminant diet with an increased cholesterol concentration in the plasma (Grummer and Carroll, ; Nogueira et al., ). These effects were not observed in the present study, because the prepubertal goats did not present a negative energy balance, and the inclusion of soya bean oil did not increase urea and cholesterol levels.…”

“…Furthermore, the inclusion of fat in the diet of heifers results in a significant increase in the synthesis of steroid hormones (Butler et al., ; Mattos et al., ; Nogueira et al., ), and the inclusion of 3% soya bean oil in the diet of heifers is sufficient to induce puberty (Whitney et al., ; Fouladi‐Nashta et al., ). Similarly, the inclusion of soya bean oil in the diet of prepubertal goats may be used as a management strategy to accelerate puberty and increase the reproductive efficiency of the herd (Whitney et al., ; Ying et al., ).…”

Supplementation of cows with linseed: effects on antral follicle count, oocyte quality, and nutritional and plasma metabolite parameters

“…After seven OPU sessions, no difference was observed in AFC among sessions of cows supplemented or not supplemented with linseed. The effects of the addition of PUFAs in the diet of cattle on AFC are quite controversial, and studies showing positive effects or no effect can be found (BILBY et al, 2006;FOULADI-NASHTA et al, 2009;PONTER et al, 2012;NOGUEIRA et al, 2012).…”

“…Diets rich in linoleic acid, similar to that present in linseed, or with the addition of soybean oil to their formulations increase hepatic gluconeogenesis owing to the increase of rumen propionate production (THOMAS;WILLIAMS, 1996). The increase in gluconeogenesis has been associated with elevations in plasma concentrations of insulin and IGF-1, which are capable of increasing the number of small and medium follicles in Nelore heifers (NOGUEIRA et al, 2012). On the contrary, Bilby et al (2006) found that supplementing dairy cows with mono and polyunsaturated fatty acids did not lead to a difference in the number of follicles present in the ovaries.…”

“…The effects of the supply of fat on ovarian follicular count have been observed for dairy and beef cattle in all stages of lactation (GUARDIEIRO et al, 2011;FOULADI-NASHTA et al, 2009). Some authors have observed an increase in follicular count as a result of fat supplementation with Megalac® in beef cows (NOGUEIRA et al, 2012).…”