2.1. Experimental fish and rearing condition
Eggs obtained from seven female goldfish, Carassius
auratus, were fertilized with sperm taken from five males.
After hatching, larvae were fed with freshly hatched brine
shrimp nauplii (Artemia salina) for a period of 4 weeks.
Fish were fed with the commercial goldfish pellets (Energy,
Thailand). The experiment emerged 20 weeks after hatching
(June 2011). The fish (the mean body weight 2 g) were
divided evenly among four groups (120 fish per group).
Each group was placed in a 400 l fiberglass aquarium, fed
and maintained for one year until maturation. The fish
were fed with experimental diets, presented in Table 1.
In order to accustom the fish to experimental food, fish
were gradually fed with experimental diet within a week
by 20%, 40%, 60%, 80% and 100% replacement to granulated
food. The time we completely commenced feeding fish
with experimental diet was designed as zero point. Feeding
with experimental diets lasted from June to December for
a period of 28 weeks. The amount of genistein and diadzein
within the food is presented in Table 1 showing each treatment
diet composition