Search

Hossain MK, Iehata S , Noordin NM, Kader MA, Emilia SN, Sung YY, Abol-Munafi AB. 2022. Isolation and identification of potential host probiotic bacteria from Malaysian mahseer, Tor tambroides for aquaculture practices. Biodiversitas 23: 5423-5430. The digestive tract has been revealed as a reservoir of potential probiotics derived from the host. The goal of this study was to isolate, identify, and characterize putative host-associated probiotic bacteria (HAPs) from the digestive tract of Malaysian mahseer Tor tambroides. To evaluate potential T. tambroides HAPs, in-vitro digestive enzyme activity (such as a cellulolytic, proteolytic, and lipolytic activity) and antibacterial activity against two fish pathogens (Vibrio parahaemolyticus and Aeromonas hydrophila) were utilized. Thirty-seven isolates with digestive enzyme activities were tested for their ability to inhibit pathogenic bacteria growth using an agar well-diffusion assay. Three isolates displayed in-vitro suppression of pathogenic bacteria, with two strains (KT03 and KM07) inhibiting the growth of V. parahaemolyticus and one strain (KT27) suppressing the proliferation of both harmful bacteria (V. parahaemolyticus and A. hydrophila). Strains KT03 and KM07 exhibited the most resemblance to Enterococcus faecalis (strains 2674 and FC11682, respectively) based on 16S rRNA sequences, whereas KT27 had a 97% similarity to Aeromonas sp. A8-29. The study’s findings provide valuable data on the prospective use of these three isolates (KT03, KT27, and KM07) as potential HAPs for better understanding their physiological activities, such as growth and disease resistance on T. tambroides.

The present research was conducted to investigate the effects of fish oil (FO) substitutions with corn oil (CO) on the gonad development of female Tor tambroides broodstocks, a high value freshwater fish. Three isonitrogenous (450 g kg−1 crude protein) and isolipidic (105 g kg−1 crude lipid) were formulated to contain FO and CO at a ratio of 1:0, 1:1 and 0:1, respectively, and fed to female fish (n = 10 fish × 3 replicate × 3 treatment; average weight = 910.0 ± 130.0 g) for five months. At the end of the feeding trial, there were no significant differences (p > .05) on the gonadosomatic index (GSI), hepatosomatic index, 17β-oestradiol (E2) concentration and muscle fatty acids (FA) composition. However, fish fed with diet containing FO to CO at a ratio of 1:1 demonstrated higher percentage of GSI, E2 concentration (ng ml−1) and the presence of vitellogenic oocytes in the histological data compared to the other two feeding diets. The FA composition also highlighted that T. tambroides broodstocks can elongate polyunsaturated FA to highly unsaturated FA. Based on these preliminary results, it shows that T. tambroides prefer diets with supplementation of both n3 and n6 oil source. However, more studies need to be done to strengthen this conclusion.

This study examined the effects of dietary cholesterol on the survival, molting pattern, and growth of early juveniles of the blue swimmer crab, Portunus pelagicus. Seven isocaloric diets were formulated to contain cholesterol at 0 (basal diet), 2.5, 5.0, 7.5, 10, 12.5, and 15 g/kg diet dry weight. Survival ranged from 20 to 47.5%, with the highest survival recorded for crabs fed the diet supplemented with 10 g/kg cholesterol, while the lowest survival was demonstrated by crabs fed the basal diet. The highest occurrence of molt death syndrome was found for crabs fed the diet with cholesterol supplementation of 15 g/kg. A general trend of decreasing development time to the crab 3 (C3) stage was observed with increasing dietary cholesterol supplementation up to a level of 10 g/kg, but this then decreased as dietary cholesterol level was increased to 12.5 and 15 g/kg. The specific growth rates of crabs, calculated for dry weight, carapace width, and carapace length, followed a similar trend. Our results suggest that, under the current feeding conditions, a dietary cholesterol level of 10 g/kg appears to be optimal for the culture of early juveniles of P. pelagicus.

A number of studies have investigated different crustacean food stuffs, feeding methods, 18 and feeding behavior, but little attention has been given to the interaction between these aspects in 19 crustaceans. The aim of the present review is to update knowledge, and examine challenges and 20 opportunities in the development of formulated diets, as pelleted feed, which is vital for developing 21 better quality of seed or broodstock in hatcheries, and adaptation of hatchery product to the aqua- 22 culture environment, and production systems.

Ecdysis is a common phenomenon that happens throughout the life phase of the giant freshwater prawn Macrobrachium rosenbergii. It is vital to better understand the correlation between cannibalism and biochemical compound that exists during the moulting process. The objective of the present study was to determine the amino acid profile released by M. rosenbergii during the ecdysis process that promotes cannibalism. To accomplish this, changes in amino acid levels (total amino acid (TAA) and free amino acid (FAA)) of tissue muscle, exoskeleton, and sample water of culture medium from the moulting (E-stage) and non-moulting (C-stage) prawns were analysed using high-performance liquid chromatography (HPLC). Comparison study revealed that among the TAA compounds, proline and sarcosine of tissues from moulting prawn were found at the highest levels. The level of FAA from water that contains moulting prawns (E-stage) was dominated by tryptophan and proline. Significant values obtained in the present study suggested that these amino acid compounds act as a chemical cue to promote cannibalism in M. rosenbergii during ecdysis. The knowledge of compositions and compounds that were released during the moulting process should be helpful for better understanding of the mechanism and chemical cues that play roles on triggering cannibalism, and also for future dietary manipulation to improve feeding efficiencies and feeding management, which indirectly impacts productivity and profitability.

The data collection was initiated to evaluate the effects of supplementary phospholipid to non-fishmeal based diet in order to make functional diets for the Malaysian Mahseer, Tor tambroides. Four iso-nitrogenous and iso-lipidic diets were formulated to consist 100% fishmeal (FM100), 0% fishmeal or full fishmeal replacement (FM0), and 0% fishmeal supplemented with 4% phospholipids (FM0+4%PL), 6% phospholipids (FM0+6%PL). A 60-day feeding trial was conducted and data collection was carried out for the following parameters; growth indices, somatic parameters, whole body nutrient composition, muscle fatty acid composition, haematocrit value and serum lysozyme activity. Fish fed FM0 diets showed significantly poor performance (P

This study examined the effects of dietary phospholipid (PL) level on survival, growth, development and resistance to osmotic shock of early blue swimmer crab, Portunus pelagicus, juveniles. Six iso‐lipidic diets formulated to contain PL at 0 (basal), 30, 60, 90, 120 and 150 g/kg (dry matter) were offered to first‐stage crabs (C1) until they achieved C4 stage. Highest survival (93.3%) was achieved by crabs fed diets with PL supplementation levels of 120 and 150 g/kg. Crabs fed diets with PL supplementation levels of 120 and 150 g/kg developed to C4, on average, in 14 days, which was significantly faster (p 0.05). Dietary PL level markedly influenced survival of juveniles exposed to a stress test of low salinity (7 g/L); most crabs (>87%) fed diets supplemented with PL at 120 and 150 g/kg survived to the end of stress test. Dietary PL levels of 120 g/kg and 150 g/kg are suggested to maximize productivity in early P. pelagicus culture.

This study was investigated to examine supplemental effects of dietary inosine monophosphate (IMP) on growth performance, feed utilization, biochemical, hematological and immunological parameters of juvenile Nile tilapia Oreochromis niloticus. Disease resistance to experimental infection with Streptococcus agalactiae was also assessed. A semi-purified basal diet was supplemented with 0 (IMP0, Control), 1 (IMP1), 2 (IMP2), 4 (IMP4) and 8 (IMP8) g purified IMP kg−1 diet to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish (0.59 g) for 60 days. The results indicated that supplementation of IMP significantly (P 0.05). Among whole body proximate composition and somatic parameters, condition factor was significantly influenced by dietary supplementation of IMP. A wide variation in hematological parameters were observed and dietary supplementation increased the hematocrit content (P 0.05). Total serum protein (TSP), lysozyme activity (LA), superoxide dismutase activity (SOD) and bactericidal activity (BA) tended to increase with the supplementation of dietary IMP. TSP and SOD were significantly improved with ≥4 g kg−1 supplementation, while LA with 8 g kg−1 and BA with ≥1 g kg−1 supplementations. IMP supplemented groups showed higher (P > 0.05) cumulative survival compared to that of supplementation free control group. IMP supplemented diet groups also showed significantly higher BA in the post challenge test. Based on the overall performances, the results of the current study indicated that the inclusion of IMP in Nile tilapia diet can improve growth performance, feed utilization, haematological and immunological parameters; and disease resistance of juvenile Nile tilapia. Keywords: Nucleotides, Inosine monophosphate, Growth, Immunity, Disease resistance, Nile tilapia, Streptococcus agalactiae

This study aimed to determine the effects of different diets on morphological development and fatty acids profile of different ovarian developmental stages of mud crab Scylla olivacea. Captive crabs were fed with two different diets; blood cockle Anadara granosa and fish, Decapterus sp. Through the morphological examinations, ovarian maturation stages of wild (control group) and captive S. olivacea (experimental group) were classified into four stages; Stage 1 (translucent to off white in color), Stage 2 (pale yellow), Stage 3 (light yellow) and Stage 4 (reddish orange). Fatty acid composition obtained during ovarian maturation of S. olivacea indicated that, concentration of total fatty acids, saturated fatty acids, monounsaturated fatty acid and polyunsaturated fatty acid in wild crabs, crabs fed with blood cockle and fish increased from Stage 1 to 3 ovaries and showed a decline pattern in Stage 4. The difference between these treatments were not significant (P > 0.05). The results also demonstrated that ovarian maturation stages of S. olivacea were also closely related to fatty acid compositions. Anadara granosa and Decapterus sp. can be used to feed S. olivacea in captivity to induce their ovarian maturation. The results from the present study indicated the suitable selection of natural diets for broodstock of S. olivacea in captivity. Statement of relevance This article is suitable with Aquaculture journal because the findings contribute to the mud crabs' aquaculture industry and aquaculture scientist in the near future. Feed and feeding related to the ovarian maturation stages are important to farmers to manage the suitable food types and feeding time in the mud crabs hatchery seed production. In addition, the interesting data from the present study can also be used to develop feeding protocols for optimization in diets for mud crabs broodstock production.

This study was aimed to determine the ovarian maturation stages of wild and captive orange mud crab, Scylla olivacea fed with different diets via gonadosomatic status, oocyte diameter and histological examinations. Captive crabs were fed with blood cockle, Anadara granosa, or fish, Decapterus spp. Through the histological examinations, ovarian maturation stages of wild and captive S. olivacea was classified into four stages: Immature (Stage 1), Early maturing (Stage 2), Pre-maturing (Stage 3) and Fully matured (Stage 4). Gonadosomatic Index of wild and captive crabs remained low during immature and 2 but increased significantly (p

Culturing microalgae using commercial media is expensive. Proliferation of aquaculture is generating high amount of wastewater containing nitrogen and phosphorus and this could be a source of nutrient for cultivating microalgae thereby reducing the production costs. This study compared the growth, productivity, and proximate composition of Chaetoceros calcitrans, Nannochloris maculate, and Tetraselmis chuii cultured in aquaculture wastewater and Conway medium. Results indicated that selected microalgae cultivated in wastewater and Conway medium did not show any significant differences (p > 0.05) in terms of cell density, optical density, and biomass. Further, volumetric and areal productivity showed similar trend for all the three species. But lipid productivity (LP) in N. maculate was significantly higher (p 0.05) for C. calcitrans and T. chuii in terms of LP when cultivated in the...

Identifying suitable alternatives to fish oil for inclusion in formulated diets for aquaculture species is becoming increasingly important; however, relatively few studies have assessed the potential of terrestrial oils as possible replacements for fish oil in diets for marine crustaceans. This study examined the potential of soybean oil as a partial or complete replacement for fish oil in diets for blue swimmer crab Portunus pelagicus juveniles. Seven iso-nitrogenous and iso-lipidic diets were formulated to contain soybean oil to fish oil ratios of 1:0. 3:1. 2:1. 1:1. 1:2. 1:3. and 0:1. They were fed to first-stage crabs over four molts and survival, development, and growth of the crabs were measured. Crabs fed the diet containing soybean oil as the sole lipid source (i.e., soybean oil:fish oil ratio 1:0 treatment) recorded the lowest survival among treatments, significantly longer intermolt duration, and significantly lower specific growth rates compared with other treatments. Improved performance was shown by crabs fed diets containing fish oil at the same, or higher, dietary level than soybean oil but the best survival, shortest intermolt duration, and fastest growth rates were recorded for crabs fed the diet containing the soybean oil:fish oil ratio of 1:1. The results indicated that P. pelagicus juveniles require a balance of dietary n-3 and n-6 fatty acids and thus dietary lipid requirements can be met partially by soybean oil. Diets containing soybean oil are cheaper to produce than traditional fish oil—based diets and soybean oil is a more sustainably sourced ingredient than fish oil. Our results should support further development of the P. pelagicus aquaculture industry.

Blue swimmer crab, Portunus pelagicus , juveniles are weak osmoregulators leading to reduced survival and growth outside salinities of 15–35‰. Therefore improving the performance of this commercially important crab at sub-optimal salinities through diet manipulation will likely benefit the aquaculture industry. The aim of the current experiment was to determine whether increased dietary LC-PUFA, in the form of fish oil, could improve the survival, growth and hemolymph ion maintenance of early P. pelagicus juveniles at salinities of 14, 30 and 42‰. Crabs were fed five diets containing 0, 3, 6, 9 and 12% fish oil inclusion levels (% dry diet weight) and their survival and growth were measured over 20 days. After 20 days, the hemolymph Na + , K + and Ca 2+ levels of the crabs were measured. Seven replicates, with three crabs in each replicate, were used in each salinity/dietary treatment (total of 315 crabs). Results showed diets containing 0% fish oil inclusion led to the lowest survival in all salinities, although this was only significant (p 0.05) compared with those fed the same diet but at a salinity of 30‰. Between salinities of 14 and 30‰, no significant growth difference was detected although the growth benefit to increased dietary LC-PUFA at 14‰ was more obvious than at 30‰. Meanwhile, at salinities of 14 and 42‰, hemolymph Na + regulation was significantly improved through dietary LC-PUFA supplementation, indicating that LC-PUFA is an essential nutrient for undisrupted ion-regulation. These findings indicate that the productivity of P. pelagicus juveniles may be increased at sub-optimal salinities through dietary LC-PUFA supplementation, which may be linked with improved hemolymph ion maintenance.