Copepods play a major role as food link for larger animals and it is also important as a live food source for the aquaculture industry. There are only few reports on the influence of temperature and salinity towards the growth and development of tropical copepods. In this study, the effect of temperature (5 and 25°C) and salinity (5, 10, 25 and 30 psu) on population growth and density of a marine harpacticoid, Pararobertsonia sp. in a laboratory condition is investigated. The species was first obtained from seagrass samples from Merchang estuary, Terengganu, which receives seawater from the South China Sea. It has been cultured in the laboratory condition through generations. The findings show that there is a significant difference (P<0.05) detected between the salinity treatment and it shows that difference in salinities give different effects on the population number of the harpacticoids cultured in the same temperature (25 ± 1°C). On the other hand, harpacticoids reared in cold temperature (5 ± 1°C) did not survive the condition. Harpacticoids reared in 25 psu salinity show the highest population density (mean of 3.7 ind./ml), but the most stable population growth is shown in 35 psu treatment as shown by its high value of maximum specific growth rate (K). From this experiment, it can be concluded that 35 psu and temperature of 25 ± 1°C is the optimum condition for the maximum production of a tropical Pararobertsonia sp. in the laboratory condition.
The purpose of this study was to evaluate the influence of a synbiotics between Lactobacillus plantarum and mannan-oligosaccharides (MOS) extract and probiotics (Lactobacillus plantarum) on growth performance in red hybrid tilapia (Oreochromis mossambicus x Oreochromis.niloticus). The fishes with initial average weight 11.9 ± 0.7g were randomly assigned to three dietary treatments which were fed on a diet containing probiotics only and a diet combination of probiotics and prebiotic (synbiotics), with four replicates for each treatment. The control group was fed without supplementation of any probiotics or prebiotics for the same duration. All the diets were isocaloric and isonitrogenous. All fish were fed daily at 3% of the body weight per day in two equal instalments. The feeding rate was kept at 4% body weight day-1 for the whole rearing period of 30 days, and the amount of feed was adjusted every tenth day following a bulk weighing of each group of fish. All diets contained about 32% of crude protein. Significantly (P < 0.05) high growth performance (percent gain body weight, weight gain and feed intake) were observed in the group fed diet containing synbiotics as compared to probiotics and control group. Similarly, significantly (P < 0.05) low FCR was recorded in synbiotics as compared to probiotics and control group. This result revealed that a feeding regime with synbiotics for 30 days led to a significant increase in growth performance, survival rate and feeding efficiency in red hybrid tilapia fingerlings.