S. M. Nurul Amin

Improvement of feed pellet characteristics by dietary pre-gelatinized starch and their subsequent effects on growth and physiology in tilapia

A 9-week study was conducted to compare dietary corn starch (CS) or tapioca starch (TS), with or without being pre-gelatinized (PG), on the growth, feeding efficiencies, plasma and muscle biochemistry, intestinal short chain fatty acids (SCFA), and liver glycogen of triplicate groups of 20 red hybrid tilapia (Orecohromis sp.). Various pellet characteristics were evaluated, along with their surface and cross sectional microstructure. The PG diets had significantly higher water stability, bulk density, and protein solubility, along with a smoother surface. Tilapia fed the TS diet had lower growth than had all other tilapia, but were significantly improved when diet was pre-gelatinized. In the PG treatments, intestinal SCFA significantly decreased while plasma glucose, cholesterol and triglycerides, as well as liver glycogen, significantly increased. Fish fed the CS diet had significantly more long chain polyunsaturated fatty acid than had those fed by other treatments. Pre-gelatinization may improve fish productivity and offer greater flexibility during aquafeed production.

A mini review on immune role of chemokines and its receptors in snakehead murrel Channa striatus

ABSTRACT Chemokines are ubiquitous cytokine molecules involved in migration of cells during inflammation and normal physiological processes. Though the study on chemokines in mammalian species like humans have been extensively studied, characterization of chemokines in teleost fishes is still in the early stage. The present review provides an overview of chemokines and its receptors in a teleost fish, Channa striatus. C. striatus is an air breathing freshwater carnivore, which has enormous economic importance. This species is affected by an oomycete fungus, Aphanomyces invadans and a Gram negative bacteria Aeromonas hydrophila is known to cause secondary infection. These pathogens impose immune changes in the host organism, which in turn mounts several immune responses. Of these, the role of cytokines in the immune response is immense, due to their involvement in several activities of inflammation such as cell trafficking to the site of inflammation and antigen presentation. Given that importance, chemokines in fishes do have significant role in the immunological and other physiological functions of the organism, hence there is a need to understand the characteristics, activities and performace of these small molecules in details. Graphical abstract Figure. No caption available. HighlightsInformation of chemokines in teleost is still in the early stage.This review provides an overview of chemokines and its receptors in a teleost, Channa striatus.Pathogen in the teleost mounts an immune response involving cytokines.Chemokines in fishes have significant role in the immunological functions.Chemokine receptors have a comprehensive perception on the chemokine immune complex.

Trypsin-modulating oostatic factor (TMOF) decreased the survival, growth and digestion enzymes of Macrobrachium rosenbergii

Trypsin-modulating oostatic factor (TMOF) is an effective mosquito larvicide, but information on its potential toxicity to non-target organisms is limited. To investigate this, triplicate groups of 10 Macrobrachium rosenbergii were exposed to 0, 10, 50 or 100 mg/L nominal TMOF concentrations for 12 days. Tail moisture, crude protein, and hepatopancreatic glycogen/histopathology were unaffected, but increasing TMOF linearly decreased survival and growth. TMOF at the lowest concentration employed significantly decreased trypsin and chymotrypsin activities.

Length–weight relationships of the tropical cephalopod Uroteuthis chinensis (Gray, 1849) from Sabah, Malaysia

This study focuses on the length–weight relationships (LWR) and the relative condition factor (Kn) of Uroteuthis chinensis from the Marudu Bay, Malaysia. The mean mantle length (±SE) and the total body weight (±SE) of U. chinensis were 29.02 ± 1.31 mm and 3.37 ± 0.46 g, respectively. The calculated growth coefficient b was 2.579, which indicated the hypoallometric growth of the animals from the study area. The study also showed that the dorsal mantle length and the total body weight were highly correlated (r = 0.930, p < 0.001). The mean values of the relative condition factor (Kn) of U. chinensis were found to be 1.0062 ± 0.1134. To our knowledge, the LWR and condition indices of U. chinensis collected from the Marudu Bay presented herein represent the first reference available to Malaysian waters.

The influence of environmental parameters on fish larval distribution and abundance in the mangrove estuarine area of Marudu bay, Sabah, Malaysia

The aim of this study was to estimate the influence of selected environmental parameters on the fish larval distribution and abundance between October 2012 and September 2013 in the Mangrove estuarine area of Marudu bay, Sabah, Malaysia. Fish larvae samples were collected monthly using plankton net of 350 m of mesh size with a mouth opening of 40.5 cm in diameter through 20 min surface tows. Five different stations were chosen in this study. In total 3,879 larvae, belonging to 20 families were recorded, with a mean abundance of 118 larvae per 100 m 3 . Among 20 families, top four families such as Sillaginidae (44%), Engraulidae (14%), Mugilidae (12%) and Sparidae (10%) occurred consistently around the year in the study areas. Sillaginidae was the most abundant larval fish families. In situ environmental parameters such as water temperature, dissolved oxygen (DO), salinity, pH and conductivity were recorded during the sampling times. Significant variations were found in the environmental parameters among the five stations except DO and pH (p < 0.05). It is revealed that mainly four families (centriscidae, Engraulidae, Mugilidae, and Sillaginidae) were significantly influenced by the abiotic factors. Of the environmental parameters recorded, salinity appeared to be the main factor affecting the distribution and abundance of Mugilidae families. Overall, regression analysis test indicated a weak overall correlation between larval assemblage and environmental parameters in the estuary of Marudu Bay.

Phylogenetics and population genetics of Plotosus canius (Siluriformes: Plotosidae) from Malaysian coastal waters

Plotosus canius (Hamilton, 1822) is a significant marine species in Malaysia from nutritional and commercial perspectives. Despite numerous fundamental research on biological characteristics of P. canius, there are various concerns on the level of population differentiation, genomic structure, and the level of genetic variability among their populations due to deficiency of genetic-based studies. Deficiency on basic contexts such as stock identification, phylogenetic relationship and population genetic structure would negatively impact their sustainable conservation. Hence, this study was conducted to characterize the genetic structure of P. canius for the first time through the application of mitochondrial Cytochrome Oxidase I (COI) gene, cross amplification of Tandanus tandanus microsatellites, and a total of 117 collected specimens across five selected populations of Malaysia. The experimental results of the mitochondrial analysis revealed that the haplotype diversity and nucleotide diversity varied from 0.395–0.771 and 0.033–0.65 respectively. Moreover, the statistical analysis of microsatellites addressed a considerable heterozygote insufficiency in all populations, with average observed heterozygosity (Ho) value of 0.2168, which was lower than the standard heterozygosity in marine populations (Ho = 0.79). This alongside the high Fis values estimation, high pairwise differentiation among populations and low within population variations are supposed to be associated with small sample size, and inbreeding system. Besides, the significant finding of this study was the sharing of common haplotype KR086940, which reflects a historical genetic connectivity between Peninsular Malaysia and Borneo populations due to the geological history of Southeast Asia during Pleistocene era. Demographic analyses showed that all populations were in an equilibrium state with no significant evidence of population expansion. To put it briefly, the current study has managed to provide an initial genomic database toward understanding of the genetic characterization, phylogenetic, molecular diversification and population structure in P. canius, and should be necessary highlighted for appropriate management and conservation of species. Further studies must be carried out involving more geographical and sampling sites, larger population size per site, and utilization of species specific microsatellites loci.

A comparative transcriptome approach for identification of molecular changes in Aphanomyces invadans infected Channa striatus

Snakehead murrel, Channa striatus is an economically important aquatic species in Asia and are widely cultured and captured because of its nutritious and medicinal values. Their growth is predominantly affected by epizootic ulcerative syndrome (EUS) which is primarily caused by an oomycete fungus, Aphanomyces invadans. However, the molecular mechanism of immune response in murrel against this infection is still not clear. In this study, transcriptome technique was used to understand the molecular changes involved in C. striatus during A. invadans infection. RNA from the control (CF) and infected fish (IF) groups were sequenced using Illumina Hi-seq sequencing technology. For control group, 28,952,608 clean reads were generated and de novo assembly was performed to produce 60,753 contigs. For fungus infected group, 25,470,920 clean reads were obtained and assembled to produce 58,654 contigs. Differential gene expression analysis revealed that a total of 146 genes were up-regulated and 486 genes were down regulated. Most of the differentially expressed genes were involved in innate immune mechanism such as pathogen recognition, signalling and antimicrobial mechanisms. Interestingly, few adaptive immune genes, especially immunoglobulins were also significantly up regulated during fungal infection. Also, the results were validated by qRT-PCR analysis. These results indicated the involvement of various immune genes involved in both innate and adaptive immune mechanism during fungal infection in C. striatus which provide new insights into murrel immune mechanisms against A. invadans.

Effects of Feeding Frequencies on the Growth, Plasma Biochemistry, and Liver Glycogen of Jade Perch Scortum barcoo in a Recirculating System

AbstractJade Perch Scortum barcoo having an initial average weight of 7.28 ± 0.13 g (mean ± SE) were cultured in a recirculating system at different feeding frequencies that included one, two, three, or four meals a day at 5% body weight per day. Treatments were performed in triplicate using 65 fish in each replicate. After 72 d, the survival, growth, feeding efficiencies, body indices, plasma biochemistry, whole-body proximate composition, and muscle cholesterol were measured while histological sections of the liver were stained for glycogen with periodic acid Schiff. Results showed that growth was best when fish were fed three times a day, which was significantly higher than those fed one, two or four times a day. Feeding efficiencies were significantly better for fish fed two or three times a day. Plasma glucose, plasma cholesterol, periodic acid Schiff staining intensity of the liver, and hepatosomatic index were significantly higher for fish fed three times a day compared with once a day. Whole-body ...

Temperature induced variation in oxygen consumption of juvenile and adult stage of the dog conch Laevistrombus canarium (Linnaeus 1758)

Laevistrombus canarium Linnaeus, 1758 is one of the important edible sea snail within the western Johor Straits, Malaysia. In this study, the impact of temperature on oxygen consumption (MO2) of L. canarium based on their ontogenetic changes (juvenile and adult) was measured in the laboratory condition at 22.0, 26.0, 30.0 and 34.0°C. Measurement of MO2 were taken every 1 s for 60 min on 4.20 – 34.00 g dog conch using respirometry chamber. All experiments were carried out in static conditions in five replicates with one snail per chambers. The results of oxygen consumption showed that juvenile dog conch respired at the rate of 0.163 ml h−1 and adult respired at the rate of 0.119 ml h−1. Consequently, the oxygen consumption in juvenile and adult dog conch was expressed as a total energy spends. The results indicates that total energy spend for oxygen consumed (ml h−1) of L. canarium at different temperature regimes (22.0 to 34.0°C) slightly increased over time period (0.63 ± 0.12 to 3.24 ± 0.05 J h−1) respectively. This finding of the present study suggested L. canarium is well adapted for life in high temperature environment.