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This study is conducted to examine the impacts of different rearing temperature and diet variation on haematological and serum biochemical parameters on the juvenile Lutjanus malabaricus, a commercially important fish species in Malaysia. Fish (16-18 cm) were divided into eight treatments (4 temperatures × 2 diets) each with three replicates of five juveniles each. Fish were subjected to four different rearing temperatures (22, 26, 30 and 34°C) and fed with a commercial pellet and a natural shrimp diet. After 30 days of experimental period, blood samples were collected and transferred into two different tubes from each sample: One containing EDTA as an anticoagulant agent and the other without EDTA for serum collection. All the haematological and biochemical parameters in all the treatments were within the normal range. Changing temperature and diet led to a significant change (p 0.05). The fish reared at 26°C and 30°C had significantly higher values than those reared at 22°C and 34°C (p

Laevistrombus canarium (Linnaeus 1758) or the dog conch is a highly important fishery species with great potential for introduction into aquaculture. The present study evaluates food consumption and assimilation by the adult conch at different temperatures (i.e. 22°C, 26°C, 30°C and 34°C). The conchs were acclimated for one week in stocking tanks with well-aerated seawater of 30 PSU salinity and at ambient temperature of 26°C. Prior to experimentation, the gastric emptying level of the conchs were standardized by allowing them to feed till satiation, followed by 24 h starvation. Ten similar sized aquaria (20 x 15 x 15 cm) were used, each containing one individual conch. Each conch was provided with similar quantity of food (~ 102.13 ± 0.45 mg of sinking pellets) and they were allowed to feed within a 24 h period. The food consumption rate for adult conchs was significantly different (p

Elevated ocean water temperature influences the physiological properties of fishes. This study is expected to characterize the oxygen consumption rate (OCR) and gill morphology in different temperature in hybrid grouper, tiger grouper × giant grouper (TGGGH). TGGGH specimens were distributed into four temperature groups starting from 22, 26, 30 and 34 °C within a recirculatory system under controlled conditions for 30 days in triplicates. Intermittent flow respirometry was directed to distinguish the impact of temperature on the OCR, and scanning electron microscopy was conducted to observe the gill morphology. Results indicated that the OCR of TGGGH increased significantly from 22.98 ± 1.16 mg O2 h−1 to 37.08 ± 1.56 mg O2 h−1 when temperature increased from 22 to 34 °C. Values of respired energy (RE) increased from 456.35 ± 11.41 Jh−1 at 22 °C to 737.88 ± 3.79 Jh−1 at 34 °C. Meanwhile, values of temperature quotients (Q10) were maximum at 22 °C–26 °C and minimum at 26 °C–30 °C. The favored temperature assessed from Q10 was between 26 °C and 30 °C. Gill lesions were significantly observed at 22 °C and 34 °C. The outcomes proposed that this fish species may neglect to maintain sufficient O2 uptake in future atmospheric situations. Thus, optimum oxygen consumption is required for maintaining the TGGGH in aquaculture environment.

Rising of temperature in conjunction with acidification due to the anthropogenic climates has tremendously affected all aquatic life. Small changes in the surrounding environment could lead to physiological constraint in the individual. Therefore, this study was designed to investigate the effects of warm water temperature (32 °C) and low pH (pH 6) on physiological responses and growth of hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) juveniles for 25 days. Growth performance was significantly affected under warm water temperature and low-pH conditions. Surprisingly, the positive effect on growth was observed under the interactive effects of warm water and low pH exposure. Hybrid grouper exposed to the interactive stressor of warm temperature and low pH exhibited higher living cost, where HSI content was greatly depleted to about 2.3-folds than in normal circumstances. Overall, challenge to warm temperature and low pH induced protein mobilization as an energy source followed by glycogen and lipid to support basal metabolic needs.

This study aims to elucidate the gastric emptying process of clownfish fed on artificial diet using two gastric evacuation models and to determine the pepsin activity in the digestion process in relation to feeding time. Regression analysis was used to evaluate the adequacy of 2 models; Anderson’s [St = So(1-So(α-1)ρ(1-α)t)1/(1-α) + ξ ] and Grove’s model [St = (Soα – αKt)1/α ], in describing the gastric emptying rate. Grove’s model provided a better fit with higher r2 value, with the calculated parameters of maximum meal size at time 0 (S0) = 0.195 g and gastric emptying rate (K) = 0.0165 g h-1. There was no initial delay phase as predicted and the evacuation followed a curve. Pepsin activity in the stomach showed rapid responses to food intake, where activity was detected at 1 h after feeding and reached its peak at 2 h after feeding. Pepsin activity decreased since then until the 12th h after feeding where it reached the lowest point. An increase of pepsin activity was detected later, where a small boost was detected at 24 h after feeding to digest the remaining food item in the stomach before the pepsin secretion decreased and maintained at pre-feeding level. Fast response of digestive enzyme in stomach implied that clownfish is equipped to utilize infrequent and irregular meals effectively.

The effects of salinity on the gastric emptying time (GET) and absorption of nutrient along the alimentary tract of tiger grouper (TG) × giant grouper (GG) (Epinephelus fuscoguttatus × E. lanceolatus) hybrid were studied. Juveniles TG×GG hybrid grouper (10.0 ± 0.5 cm total length; 50.5 ± 2.0 g) were reared in different salinities (10, 15, 20, 25 and 30 parts per thousand (ppt)) and fed with commercial pellet diet during the 60-day experimental period. The fish were then slaughtered sequentially at different time intervals after initial feeding to obtain GET. Our results showed that low salinity (10-20 ppt) lead to a shorter GET in the hybrid grouper. The shortest and longest GETs were observed in 15 ppt (12 h) and 30 ppt (18 h) treatments, respectively. Apparent digestibility coefficient (ADC) using ash contents was measured to determine the absorption of nutrient in each treatment. The absorption of macronutrient in TG×GG hybrid grouper was increased as the salinity decreased. The highest absorption occurred in 15 ppt (72% protein, 75% lipid, 68% carbohydrate and 74% energy) while the lowest absorption occurred in 30 ppt (59% protein, 64% lipid, 34% carbohydrate and 55% energy). The findings of this study suggested that 15 ppt salinity facilitates faster digestion and maximize the nutrient absorption of TG×GG hybrid and may enhance the growth rate of this newly developed grouper species.

In this study we analyzed the effects of water temperature and diet on the growth properties and gastric emptying period of juvenile Malabar blood snapper (Lutjanus malabaricus) over a 30 day experimental period. Fish were collected from a local hatchery of Pulau Ketam, Selangor, Malaysia and immediately transferred to flow-through sea water system and subjected to four different temperatures (22, 26, 30, and 34 °C) and two diets (formulated pellet and shrimp). Body weight gain, food consumption, food conversion ratio, food consumption efficiency, specific growth rate, relative growth rate, daily growth rate, and gastric emptying time were significantly influenced by temperature and diet (P

An integrated experiment was performed on juvenile Malabar blood snapper (Lutjanus malabaricus) to investigate the effect of temperature and diet in their pepsin activities in relation with digestive somatic index (IDS) and relative gut length (RGL). One hundred twenty L. malabaricus juvenile (13–15 cm) were equally distributed among four exposed temperature treatments (22, 26, 30 and 34 °C) representing their seasonal range and to account for end of century predicted temperatures, and two diets as commercial pellet and natural shrimp. After 7 days of acclimation period fish were reared for 30 days in twenty four 400 l glass aquaria at a stocking density of 5 fish tank−1. All treatments were three replications. The result showed that, IDS and RGL gradually decreased with increasing temperature up to 30 °C and again increase at 34 °C. And the values were also higher in pellet feeding fish than shrimp feeding fish at all the temperatures. Alternatively, in pepsin activity, an increased activity was seen between 26 °C to 30 °C and this activity was significantly higher than the 22 °C and 34 °C (P

Hybrid grouper (Epinephelus fuscoguttatus [TG] × E. lanceolatus [GG]) juveniles were evaluated in terms of their blood hematology and biochemical levels after 60 days of exposure to different temperatures (22 °C, 26 °C, 30 °C, and 34 °C) in triplicate (20 fish/tank; body weight 200 ± 15 g; length 22.5 ± 1 cm). The fish were fed daily with commercial pellets (42% protein, 9% ash, and 11% lipid) or shrimp (42% protein, 9% ash, and 11% lipid). Results showed that the blood hematologic parameters of the fish fed with shrimp at 26 °C were significantly better than those at other temperatures. The lowest stress level measured in terms of glucose (26 ± 10 mg dL−1) and cortisol concentrations (0.5 ± 0.1 ng mL−1) after 60 days of the experiment were observed in the fish fed with shrimp at 26 °C compared with those fed with other diets and at other temperatures. Overall, the TGGG hybrid showed the highest red blood cell and total protein counts in fish fed with a shrimp diet at 26 °C, which were healthful and less stressful conditions. Thus, the health of TGGG hybrid fed with shrimp was better than that of fish fed with other diets and at other temperatures. These findings would be useful for further studies on the management of the TGGG hybrid to increase production. Keywords: Aquaculture, Hematology, Cortisol, Grouper, Temperature

This study tested the oxygen consumption rates (OCR), energy, and thermal coefficient of juvenile Lutjanus malabaricus (60 fish, size: 4.53 ± 1.14 g) at four temperatures of 22, 26, 30 and 34 °C. During 30 days of experimental period 5 fish tank−1 were reared at four temperatures with three replicates in intermittent flow respirometers in a recirculatory system under laboratory conditions. As expected, oxygen consumption rates increased significantly (P

The influences of live and formulated feeds on growth performances, muscle fibers morphometry and muscle growth-related gene expression of Malaysian mahseer, Tor tambroides larvae were evaluated in indoor nursery rearing system. Quadruplicate groups of T. tambroides larvae (0.07 ± 0.01 g, mean ± SE) were stocked in sixteen aquaria (60 × 30 × 30 cm), randomly arranged in four dietary treatments viz. larvae fed artemia (LA), moina (LM), daphnia (LD) and formulated feed (FF) with stocking density of 34 larvae per aquarium. The larvae were fed to visually near satiation in two equal feedings per day, seven days per week for 75 days. The growth-related parameters (mean weight gain and specific growth rate) were significantly highest in treatment FF, followed by treatment LA and the lowest in treatment LD or LM. Histological observation and muscle morphometric analysis revealed that mosaic hyperplasia was observed after 50 days of the feeding trial. Hypertrophic (diameter class 50 = 40 > d ≤ 50 μm and class 60 = d > 50 μm), but not hyperplastic (diameter class ≤10 μm), muscle fibers frequencies were significantly highest in larvae fed FF compared to those fed live feeds. The entire open reading frame cDNA sequences of two important growth-related genes, myogenin and MyoD, were successfully amplified and cloned from T. tambroides larvae. The nucleotide sequences alignment using CLUSTAL W in BioEdit program of both MyoD and myogenin genes showed the sign of existence of isoforms and highly conserved with other cyprinid fishes. Real-time PCR data demonstrated that myogenin and MyoD gene expressions were significantly upregulated in larvae fed FF. The results of the present experiment concluded that the nursery rearing of T. tambroides larvae with formulated feed showed augmented muscle growth and upregulated growth-related gene expression than feeding live feeds.

The effects of temperatures (22, 26, 30 and 34 °C) and diets (commercial pellet and shrimp) on the growth properties and gastric emptying time (GET) of the tiger grouper × giant grouper (TGGG) hybrid were analyzed over a 30 day experimental period under controlled laboratory conditions. Food consumption (FC), food conversion rate (FCR), specific growth rate (SGR) and GET were significantly influenced by temperature and diet type. The highest mean SGR (1.00% BM day−1, p 0.05) were observed between any of the groups at 22 and 34 °C fed on either the shrimp or the pellet diet. The lowest statistically significant (p

In this study we aimed to analyze the effects of water temperature and diet on the length-weight relationship and condition of juvenile Malabar blood snapper Lutjanus malabaricus over a 30-d experimental period. The experiment was conducted in the laboratory using a flow-through-sea-water system. The fish were subjected to four different temperatures (22, 26, 30, and 34 °C) and two diets (commercial pellet and natural shrimp). Fish were fed twice daily. L. malabaricus exhibited negative allometric growth (b3) at 30 °C fed with shrimp diet, which indicated that fish weight increases faster than their length. The rest of the temperatures represented negative allometric growth (b

Temperature- and prey-specific gastrointestinal evacuation times and gastrointestinal emptying rates were estimated for Lutjanus malabaricus under laboratory condition by using X-radiography and serial slaughtering techniques. Fish were collected from Pulau Ketam, Selangor, Peninsular Malaysia and subjected to four different experimental temperatures (22 °C, 26 °C, 30 °C and 34 °C) and two different types of feeding (pellet diet or shrimp (Acetes sp.)). The results of X-radiography and serial slaughtering showed that the initial voidance of faecal matter began 4–8 h after feeding at all temperatures. The fastest gut emptying time and rates were seen in the 30 °C group fed with shrimp diet (16 h), where the proportion of meal remaining in the stomach decreased from 100% to less than 8% after 12 h of starvation. A significant delay in gut emptying was observed in the 22 °C group fed with formulated pellet diet (28 h). The best performance was observed at 30 °C group fed with shrimp diet. L. malabaricus fish mass (W, g) was also incorporated into a modified square root model, which fitted the wet mass gut evacuation data obtained by the serial slaughtering method regardless of temperature and prey type (adjusted r2 > 0.99). The results of this study suggested that L. malabaricus should be cultured in 30 °C and fed with shrimp diet to optimize its commercial production and condition.

The newly developed hybrid grouper: tiger grouper (Epinephelus fuscoguttatus) × giant grouper (Epinephelus fuscoguttatus) (TG×GG), has a high resistance towards different environmental condition (eg. in euryhaline environment) due to its genetic improvement. This study aims to investigate the effects of different salinities (10, 15, 20, 25 and 30 ppt) on the gastric emptying time (GET) of the TG×GG hybrid grouper juveniles. The fish were fed with commercial pellet over a 30 days experimental period under controlled laboratory conditions. The GET was determined by X-radiographic method, using barium sulfate (BaSO4) as an inert food marker. The X-radiography images showed that the shortest GET (12 h) was observed in the 15 ppt group, whereas the longest GET (18 h) in 30 ppt group. The results suggests to culture TG×GG hybrid grouper juveniles in 15 ppt with commercial pellet diet as this salinity proliferates faster digestion process which may contribute faster growth rate of this important fish species. Overall, these findings would be useful for the betterment of TG×GG hybrid grouper aquaculture which will eventually boost up the production of this newly developed hybrid grouper species.

X-radiography can be used to estimate gastric emptying time, which is valuable in calculating food consumption and growth rates in fishes. The movement of food through the alimentary tract (gastric motility) of banded archerfish, Toxotes jaculatrix (Pallas, 1767), was observed in the laboratory under natural conditions of temperature (27 °C) and salinity (28) using X-radiography, with barium sulphate (BaSO4) as an inert food marker. Nutrient absorption along the alimentary tract (expressed as relative percentage absorption gradient) was calculated using the apparent digestibility coefficient (ADC) based on ash contents of adjacent samples. We found that initial voiding of fecal matter began 6-12 hrs after feeding commenced, and that alimentary tracts were completely emptied within 96 hrs. Considerable proportions of all macronutrients were absorbed in the short region (anterior intestine/pyloric caeca), but active absorption continued along the longer middle and posterior intestinal segments. The macro- nutrient in wild-fed T. jaculatrix differed (51% protein, 63% lipid, 20% carbohydrate, and 40% energy) from that of laboratory-fed fish (75% protein, 96% lipid, 50% carbohydrate, and 87% energy), due to the fact that the proximate contents of macronutriet in the wild-fed fish were unknown, while the diet of the laboratory-fed fish was initially known. Gut passage times in T. jaculatrix was longer than those reported in various temperate carnivorous fishes, which is surprising given the higher temperatures in the tropics, however, all previous studies were performed on cultured fish fed commercial pellets and therefore direct comparisons are not possible. Slow gut passage may depend on the types of food ingested (e.g., high chitinous mealworm) that correlated to lower food consumption. Our results generally indicated that T. jaculatrix is opportunistic feeders regardless of the macronutrient content of the prey.

Increasing carbon dioxide (CO2) in the ocean are predicted to affect vital physiological functions and possibly reduce growth of marine fish. Yet, studies on the impacts on marine fish with the increasing CO2 is still limited. Therefore, this study aimed to explore the elevated CO2 effect on the growth and welfare (condition factor, blood parameters, stress analysis, gill histology) of newly developed commercially important marine fish, tiger grouper (Epinephelus fuscoguttatus) × giant grouper (E. lanceolatus) hybrid or TGGG. TGGG juveniles were exposed for 120 days in a laboratory condition of CO2 groups: 390 μatm (control-current CO2), 610 μatm (moderate) and 1010 μatm (high) consistent with projections for CO2 concentrations in the ocean over the next 50–100 years. The experiments were done in triplicate (20 fish/tank; N = 180, total length = 20.0 ± 0.5 cm, weight = 94.0 ± 3.0 g). Results showed that the lowest specific growth rate (SGR) (0.65 ± 0.05% day−1) and condition factor (1.12 ± 0.01) were observed in high CO2. Unfavourable blood haematological and biochemical parameters were observed in high CO2 group. The highest stress level measured by glucose (102 ± 8 mg dL−1) and cortisol concentration (1.0 ± 0.1 ng mL−1) were also observed in the high CO2. Gill lesions were histologically observed in high CO2 treatment. The results suggested that high CO2 negatively affected the growth and welfare of TGGG. Outputs of this study would offers a simple tool to evaluate the potential risk of elevated CO2 to an important commercial marine grouper.

Water temperature can influence the metabolic rate of ectothermal animal such as, fish. This study aims to investigate the gastric emptying time (GET) of malabar blood snapper (L. malabaricus) at different temperature (22, 26, 30, 34°C) fed with commercial diet pellet. The gastric emptying times at different temperatures were determined X-radiographically, using barium sulfate (BaSO4) as a contrast medium food marker. The food marker and X-radiography showed that initial voidance of fecal matter began 4-8 h after feeding at all temperature. The fastest GET (18 h) was obsereved at 30°C, whereas the longest (28 h) GET was seen at 22°C. GET was increased with increasing temperature up to 30°C whereas decreased at extreme (34°C) and stress temperature (22°C). The findings of this study suggest to culture L. malabaricus at 26-30°C with commercial diet pellet as this temperature ranges escalate the faster digestion process which may contribute faster growth rate of this commercially important fish species. Overall, the data obtained from this study may have important consequences for optimization of commercial production of malabar blood snapper.

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.

Knowledge of fish gastric emptying time is a necessary component for understanding the fish feeding rates, energy budgets and commercial production of fishes in aquaculture. The hybrid grouper Epinephelus spp. is getting popular as a culture species in Malaysia for their faster growth rate compared to commonly cultured grouper species (giant grouper Epinephelus lanceolatus and tiger grouper Epinephelus fuscoguttatus). There are data suggests that elevated sea water temperature affects gastric emptying time (GET) of fishes. Hence, this study aims to study the GET of hybrid grouper at different temperature (22, 26, 30, 34°C) in laboratory condition with commercial diet pellet. The gastric emptying times (GETs) at different temperatures were determined X-radiographically, using barium sulfate (BaSO4) as a contrast medium food marker. The food marker and X-radiography showed that initial voidance of fecal matter began 4-6 h after feeding at all temperature. The fastest GET (13 h) was obsereved in the 30°C gro...

The present study was conducted to investigate the food consumption pattern and gastric emptying time using x-radiography technique in scats fish, Scatophagus argus feeding to satiation in laboratory conditions. Prior to feeding experiment, fish of various sizes were examined their stomach volume, using freshly prepared stomachs ligatured at the tips of the burret, where the maximum amount of distilled water collected in the stomach were measured (ml). Stomach volume is correlated with maximum food intake (S{sub max}) and it can estimate the maximum stomach distension by allometric model i.e volume=0.0000089W{sup 2.93}. Gastric emptying time was estimated using a qualitative X-radiography technique, where the fish of various sizes were fed to satiation at different time since feeding. All the experimental fish was feed into satiation using radio-opaque barium sulphate (BaSO{sub 4}) paste injected in the wet shrimp in proportion to the body weight. The BaSO{sub 4} was found suitable to track the movement of feed/prey in the stomach over time and gastric emptying time of scats fish can be estimated. The results of qualitative X-Radiography observation of gastric motility, showed the fish (200 gm) that fed to maximum satiation meal (circa 11 gm) completely emptied their stomach within 30 - 36more » hrs. The results of the present study will provide the first baseline information on the stomach volume, gastric emptying of scats fish in captivity.« less

This study was conducted to analyze variation in Strombus canarium larvae development, growth and survivals when cultured during wet (main reproductive period) and dry seasons. Larvae were reared at 200 larvae L(-1) in filtered seawater (0.22 microm) and fed with Isochrysis galbana at 1000 cells mL(-1) ad libitum. The culture environment was maintained at 29 +/- 1 degrees C, salinity of 30 +/- 1 PSU and photoperiod of 12:12 light dark cycle. Growth of the larvae was described on a length-at-age basis using the modified Gompertz regression. There was high correlation in shell length-at-age relationship for both wet season (R2 = 0.99) and dry season (R2 = 0.98) culture experiments. The maximal growth rate (M) and survival rate (S) were higher for larvae cultured during wet season (M = 62.44 microm day(-1), S = 14.36-2.31%), compared with dry season (M = 43.05 microm day(-1), S = 5 +/- 1.15%). The maximal attainable larval size (a) was however lower during wet season (950.19 +/- 66.93 microm shell length) compared with dry season (1343.05 +/- 586.51 microm shell length), which might be due to significantly low larvae density in the latter. Further studies are needed to investigate variation in bio-chemical composition of the egg mass, which was suggested as the main reason for the differences.

A study on elemental composition in the otolith of giant mudskipper, Periophthalmodon schlosseri, was done from June to October 2003. Specimens were obtained from the mangrove areas of Kuala Selangor, Sepang and Melaka in the west coast of Peninsular Malaysia. A total of 70 sagitta otoliths were analyzed to detect variation of Sr, Ba and Mg, replacing the natural chemical composition of the otolith, which is the calcium carbonate (CaCO3). The average ratio of Sr:Ca was 0.11 x 10(-4), Ba:Ca was 5.7 x 10(-3) and Mg:Ca was 0.2 x 10(-3). Strong correlation (R > 0.8) between fish body size and otolith weight ofmudskipper (p < 0.01) also found during this study.