Impact of Nutrition on Oocyte Quality: Cumulative Effects of Body Composition and Diet Leading to Hyperinsulinemia in Cattle1

Abstract

The present study sought to assess the combined effects of body composition and diet (level of feeding) on the postfertilization developmental potential of oocytes recovered from heifers using ultrasound-guided transvaginal follicular aspiration and to relate oocyte quality to the metabolic status of these animals. By collecting oocytes on repeated occasions spanning several weeks, it was possible to assess the cumulative effects of changes in nutritional status on oocyte quality over this period. Twenty-four heifers of low and moderate body condition were placed on one of two levels of feeding (equivalent to once or twice the maintenance requirements of these animals). Oocytes were recovered at two defined time points within each of three successive estrous cycles and were matured, fertilized, and cultured to the blastocyst stage in vitro. The results show that the effect of feeding level on oocyte quality is dependent on the body condition of the animal, with the high level of feeding being beneficial to oocytes from animals of low body condition but detrimental to oocytes from animals of moderately high body condition. Furthermore, the effects of high levels of feeding on oocyte quality were cumulative, with blastocyst yields for relatively fat heifers on twice the maintenance requirement deteriorating with time relative to yields for relatively thin heifers on the same level of feeding. Finally, a significant proportion of the moderately fat animals on the high level of feeding were hyperinsulinemic, and we show, to our knowledge for the first time in ruminants, that this condition is associated with impaired oocyte quality.

Feeding frequency has diet-dependent effects on plasma hormone concentrations but does not affect oocyte quality in dairy heifers fed fibre- or starch-based diets

“…Oestrus was synchronised using a 10-day progesteronereleasing device (CIDR; SmithKline Beecham, Tadworth, Sinclair et al (2000) and Adamiak et al (2005 and.…”

“…Full details of in vitro embryo production methodologies are given in Adamiak et al (2005 and. Cumulus-oocyte complexes (COCs) were graded according to the number of compact cumulus cell layers and granulation of the oocyte cytoplasm; denuded oocytes were rejected.…”

“…Plane of nutrition has been shown to affect the developmental competence of oocytes and this effect is dependent on the fatness of the donor animal. Adamiak et al (2005) showed that blastocyst yields were increased when lean heifers were fed at twice maintenance rather than at maintenance energy requirements, but the opposite was true for heifers in moderate body condition.…”

“…Adamiak et al (2006) showed that increased dietary starch concentration was associated with both increased plasma insulin concentrations and changes in oocyte quality, which were again dependent on the fatness of the donor heifer. In both the Adamiak et al (2005 and studies, diets were fed as two meals per day and dietary treatments altered basal plasma insulin concentrations. It is likely that these dietary treatments would have also altered post-prandial peaks in plasma insulin concentration, as a result of rapid increases in production of propionic acid in the rumen.…”

“…A secondary aim was to investigate the effect of changes in glucagon concentration on oocyte quality as glucagon concentration is known to respond to feeding (Bassett, 1975) and to be dependent on diet composition (Thorp et al, 2000). Heifers of low body fatness (body condition score (BCS) , 2.5) were used because such animals (Adamiak et al, 2005 and were more responsive to nutrition than those of greater fatness (BCS . 3.0).…”