Diets containing 3.5, 1.0 and 0.1% @entity460 were fed from the age of 42 weeks to individually caged laying hens. Ovaries were examined at 46-49 and 70 weeks of age for changes in the follicular population corresponding to the lowered egg production rates of birds given @entity460 -deficient diets (1.0% and 0.1%) and older birds given a normal diet (3.5%). Growth rates of follicles from 3.5 mm diameter to ovulation were not changed by the level of dietary @entity460 in 46-49-week-old birds. The number of atretic small follicles (less than or equal to 8 mm diam.) increased in old and @entity460 -deprived birds, resulting in lower numbers of viable follicles in the intermediate stages of growth (3-8 mm diam.). There was also an increase in the number of small follicles (1-2 mm diam.) starting to grow in 70-week-old birds which may have partly compensated for the increased loss by @entity1146 . Birds of all ages on all diets were able to produce large follicles up to ovulable size. The main feature of poor laying birds was a reduction in the ovulation rate due to the loss of large follicles (greater than 8 mm diam.) by @entity1146 , an event seen rarely in the birds with good laying performance. As @entity1146 is the normal fate of most of the small follicles, the mechanisms controlling @entity1146 in the small follicles and the large follicles appear to be independent.

Follicular growth and XXXX in the ovaries of hens (Gallus domesticus) with diminished egg production rates.

@entity1146 :: ('MESH:D018633', 'Disease') :: ['atresia'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium']
@entity1146 :: (MESH:D018633,Disease) :: ['atresia']
