Abstract
To be profitable, producers must reduce diet costs,
which can be as high as 80% of the variable costs
of an aquaculture expense. As vitamin and mineral
premixes represent a significant cost, eliminating
addition of these premixes could reduce diet costs if
no adverse effects were observed for growth and
production parameters. A 105-day feeding trial was
conducted with juvenile Australian red claw cray-
fish (Cherax quadricarinatus) to evaluate the effects
of growth, survival, body composition, processing
traits and water quality when red claw were fed a
supplemental diet containing 28% crude protein
(CP) without vitamin and mineral premixes (and
supplemented alfalfa hay) compared with red claw
fed a diet (control diet) containing 42% CP, vitamin
and mineral premixes, and with supplemented
alfalfa hay, and compared with red claw only fed
alfalfa hay when grown in ponds. Juvenile red claw
(mean weight of 15.7 1.0 g) were randomly
stocked into nine 0.02-ha ponds at a rate of 640
per pond (3.2 per m2
), and each treatment was
used in three ponds. There were two feedings per
day, each consisting of one-half of the total daily
ration. At harvest, individual weight, percentage
weight gain, specific growth rate, survival and total
yield of red claw fed a control diet was significantl