|
Title
|
Effects of the addition of Calanopia elliptica, Artemia
franciscana, and Brachionus rotundiformis in a nursery
biofloc system on water quality, growth, gut morphology,
health indices, and transcriptional response of immune
and antioxidant‑related genes in Penaeus vannamei
|
|
Abstract
|
A 56-day study was carried out to examine the addition of live foods a biofloc technology
(BFT) system on Penaeus vannamei postlarvae performance (PL25, initial weight: 0.15 g).
Four treatments were designed, including 1) control: PL were only fed with an artificial
diet (38% crude protein; 9%, crude fat) in a clear seawater system; 2) CBC: inclusion of
copepod (Calanopia elliptica, 0.2 organisms/mL) in the BFT; 3) ABC: inclusion of Artemia
nauplii (Artemia franciscana, 0.1 organisms/mL) in the BFT and 4) RBC: inclusion of
rotifer (Brachionus rotundiformis, 0.3 organisms/mL) in the BFT. Postlarvae were stocked
into twelve tanks that contained 200 L seawater (70 PL/tank). The mean values for water
temperature, salinity, and dissolved oxygen were 31.0 °C, 36 ppt, and > 5 ppm, respectively.
Total ammonia and nitrite nitrogen in BFT system were lower than the control. The highest
and lowest weight gain (4296.5 vs. 3242.2%) was in CBC and the control, respectively.
The best feed conversion ratio (FCR) value (1.22) was in CBC group. The gut’s epithelial
cell length in BFT groups was higher than the control. The highest total hemocyte count
(152.2 × 105/
mL) and total plasma protein (122.31 g/L) were in CBC group (P < 0.05). The
relative abundance of lysozyme, prophenoloxidase, superoxide dismutase, and catalase
genes mRNA transcript in the hepatopancreas of shrimps reared in the BFT that supplemented
with different live foods was higher than the control (P < 0.05). According to the
findings of the present study, the inclusion of Calanopia elliptica at a density of 0.2 organisms/
mL in BFT led to higher growth rate, better FCR, and greater immunocompetence in
P. vannamei compare to rotifer and Artemia nauplii.
|