3356 research outputs found
Sort by
Effects of Low Salinity on Growth, Digestive Enzyme Activity, Antioxidant and Immune Status, and the Microbial Community of Litopenaeus vannamei in Biofloc Technology Aquaculture Systems
No full textBiofloc technology (BFT) culture systems based on low salinity can meet the needs of
shrimp growth and environmental protection, thus having potential application. To evaluate the
effects of BFT on water quality, the microbial community, growth, digestive enzyme activity, and
antioxidant and immune status of Litopenaeus vannamei under low salinity conditions, a four-week
experiment was conducted in a BFT culture system (C/N ratio of 12: 1) with three salinity conditions:
5.0? (S5 group), 10.0? (S10 group), and 15.0?. The results showed that water quality parameters
were all within the range suitable for the culture of L. vannamei. There were no significant differences
in growth parameters such as final weight or specific growth rate. Muscle moisture, crude protein,
and crude lipid contents of L. vannamei did not differ among groups (p > 0.05). In addition, intestinal
amylase and trypsin activities in the S5 group significantly increased (p < 0.05). In the S15 group,
the superoxide dismutase activity and total antioxidant capacity in the serum and hepatopancreas
of L. vannamei, as well as serum catalase, acid phosphatase, and alkaline phosphatase activities,
markedly increased (p < 0.05). The microbial diversity (Shannon and Simpson indices) and richness
(Chao1 and ACE indices) were higher in the S5 group than in the S15 group. Our findings indicated
that although the shrimp in BFT systems with a salinity of 5?had lower antioxidant and immune
levels, the digestive enzyme activity as well as the gut microbial diversity and richness improved
compared to other groups, suggesting the possibility of culturing L. vannamei in low-saline areas with
BFT systems
Cephalopod ontogeny and life cycle patterns
No full textLife cycle definitions provide the background for conceptualizing meaningful
questions to address the mechanisms that generate different life cycle patterns.
This review provides explicit definitions and explanations of the steps in a
cephalopod life cycle, from fertilization to death. Each large step, or phase, is
characterized by a particular developmental process and morphology. Each
phase is composed of smaller developmentally distinct steps, or stages. The
cephalopod life cycle is comprised of all or some of the following phases:
Embryonic, Paralarval, Juvenile, Subadult, Adult and Senescent, and each life
cycle is taxon-specific. All cephalopods have direct development and maintain a
consistent body plan throughout ontogeny (i.e., no true larval phase and no
metamorphosis). Most cephalopods have a life cycle marked by a long early life
and a short adult life followed by senescence. Cephalopods have two
developmental modes: they produce either small planktonic hatchlings as
paralarvae, or large hatchlings as juveniles. All cephalopods go through a
Hatchling stage soon after eclosion during which they rely on two modes of
nutrition: endogenous (yolk) and exogenous (prey). Many cephalopods with
planktonic paralarvae will become benthic early in their life cycle during their
Settlement stage or remain pelagic during their Metapelagic stage. Juvenile
growth is fast and ontogenetic changes (outside of gonadal maturation)
generally cease at the end of the Juvenile phase. The Subadult phase begins
when the definitive adult morphology (except for size and body proportions) is
acquired (e.g., full complement of photophores). Sexual organs undergo most of
their development during the Subadult phase. The Adult phase starts with
spawning competency and concludes when gonads are spent. The Senescent
phase begins with spent gonads and ends with death. Using this new
terminology, we examine the patterns of cephalopod life cycles and find that
there are four main patterns based on the presence of a Paralarval phase and the
habitat occupied by each phase: Holopelagic (all phases are pelagic),
Holobenthic (all phases are benthic), Merobenthic and Meropelagic (phases
alternate between benthic and pelagic environments). In these two last
patterns, the main difference is the presence of a Paralarval phase in
Merobenthic species. The definitions and terminology proposed here provide a
unifying framework for future ecological, evolutionary and life cycles research
on cephalopods
Broadband Scattering Characteristic Quantization Technique for Single Fish Based on a Split-Beam Echosounder
No full textThe utilization of broadband quantization data increases the possibility of practical applications
for fish target recognition based on the acoustic scattering theory. However, the quantification
of broadband data is more complex than that of narrowband systems, requiring consideration of the
broadband characteristics of split-beam transducers, seawater absorption, and circuits. This paper
elucidates the scatterer acoustic field equation, transducer power equation, and signal processing
flow in split-beam broadband quantization technology for engineering applications. A broadband
calculation model based on transducer parameters is proposed to enhance the generalization ability of
broadband quantization technology to different types of sonar. The classical echo integration method
is combined with Fourier transform to meet the requirements of target strength (TS) estimation
under broadband signals. This paper includes a series of experiments to prove the rationality and
effectiveness of the method. The results demonstrate that the provided calculation model can more
accurately reflect the backscattering characteristics of the scatterer, but certain errors remain. This
article analyzes the sources of errors and validates the effectiveness of the new TS calculation metho
Merungkaikan potensi daun pokok pisang (musa x paradisiaca) dalam pengeluaran ikan laga siam (betta spendens)
Get PDF
HUBUNGKAIT ANTARA PENGAMBILAN PEMAKANAN, STATUS PEMAKANAN DAN AKTIVITI FIZIKAL TERHADAP PRESTASI KOGNITIF DALAM KALANGAN ANAK-ANAK NELAYAN DI TERENGGANU
No full textANALISIS PROTEOMIK IKAN BILIS; PENILAIAN KAEDAH PENGEKSTRAKAN PROTEIN DAN ANALISIS PEPTIDA AKTIF SECARA IN SILICO
No full textLength-weight relationships of three endemic fish species of the Arabian Peninsula
No full textLength-weight relationships (LWRs) were evaluated for three endemic fish species
collected from the north and south of inland waters of Oman in 2022 including Garra sindhae,
G. smartae, and Oxyurichthys omanensis by using foldable shrimp and crab fishing traps (mesh size
of 3*3mm) and hand nets (mesh size of 3*3mm). The parameter of b for all three species was between
the estimated ranges of 2.5-3.5 as proposed for different other fish species, and there was high and
significant coefficient of determination for all three species
Effect of Tetraselmis suecica microalgae isolated from the Persian Gulf on the expression level of AKT/mTOR genes in the liver cancer cell line, Huh7
No full textThe medicinal and therapeutic properties of microalgae, especially their anti-cancer
properties in modulating cellular mechanisms such as cytotoxicity, reducing tumor cell invasion, and
increasing apoptosis, have drawn attention to their therapeutic application in cancer. However, there are
few reports on the effects of Tetraselmis suecica microalgae on liver cancer. As the aim of this study,
after ethanolic extracting from T. suecica, and IC50 determination, the effect of T. suecica microalgae
extract on cytotoxicity and apoptosis of Huh7 cells was investigated by MTT and Annexin V/PI staining,
respectively. In addition, the expression of AKT/mTOR genes was measured by real-time PCR test.
Based on the results, ethanolic extract of T. suecica to the Huh7 cell line significantly decreased the
expression of AKT and mTOR genes compared to the control group. The vitality of cancer cells in
concentrations of 500 and 1000 ?g/ml of T. suecica extract in a 48-hour culture, decreased significantly.
In addition, in the 72-hour treatment, a significant decrease in cell viability was observed in the
concentrations of 250, 500, and 1000 ?g/ml. According to the results, T. suecica microalgae can offer
good benefits as valuable natural materials for the pharmaceutical industry, especially anticancer drugs
Experimental study on the effect of sound stimulation on hearing and behavior of juvenile black rockfish (Sebastes schlegelii)
No full textAssessing the potential impacts of wind farm noise on fish is a crucial aspect of
Environmental Impact Assessment (EIA) studies. There is increasing evidence of
disturbances and effects on hearing and behavior in animals. The black rockfish
(Sebastes schlegelii) is a commercially valuable rocky reef fish native to East Asia.
However, empirical studies that measure the actual consequences are lacking. In
this study, we used auditory evoked potentials (AEP) to assess the effects of
dominant frequency noise emitted by offshore wind farms on the auditory
sensitivity, hearing threshold, swimming, and feeding behavior of juvenile black
rockfish. The experimental findings revealed that the most sensitive sound
frequency was 200 Hz, with the lowest hearing threshold recorded at 86.4 ?
3.4 dB re 1 mPa. Following 3 and 7 days of exposure to 200 Hz noise at 110 dB,
threshold shifts in black rockfish reached 19.0 dB and 13.3 dB, respectively.
During the subsequent recovery phase, these shifts decreased to approximately
9.8 dB after 3 days, respectively. The noise-exposed group exhibited higher
swimming duration, moving distance, and caudal fin swing frequency compared
to the control group without noise exposure. Furthermore, noise prolonged the
feeding rate of black rockfish. Our findings provide the first evidence of noiseinduced
temporary threshold shift and behavioral disturbances in juvenile black
rockfish, implying potential fitness consequences associated with
noise pollutant