Characterization of molting stages in the giant freshwater prawn, Macrobrachium rosenbergii using setagenesis of pleopod

This paper characterizes the molting stages of giant freshwater prawn, Macrobrachium rosenbergii under laboratory conditions. Using the distal fifth pleopod as the main reference region and applying Drach’s classification system, we checked the epidermis and carapace hardness and documented major structural changes, such as the retraction of epidermal tissues from the cuticle and setal development. Our findings showed that in early postmolt, no development of seta matrix was observed. A closer examination of seta lumen during the intermolt stage showed that the epidermis was a densely granular structure and the internal cone was developed. In the premolt stage, a retraction of the epidermis from the cuticle (apolysis) and the formation of new seta were recorded. This study shows that using internal seta development changes is apparently a useful, easy, and practical method of determining molting stage in order to facilitate the study of molt-linked processes and metabolism

Lactic Acid Bacteria Producing Sorbic Acid and Benzoic Acid Compounds from Fermented Durian Flesh (Tempoyak) and Their Antibacterial Activities Against Foodborne Pathogenic Bacteria

Background and Objective: Antibacterial compounds produced by lactic acid bacteria are believed to replace functions of chemical preservatives. The objectives of this study were to identify lactic acid bacteria, which produced antibacterial compounds, from fermented durian flesh (tempoyak) and to assess antibacterial activities of the isolates. Material and Methods: Two bacterial identification techniques were used, including API 50 CHL kit with supplementary medium and matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF/MS). Results and Conclusion: Four various lactic acid bacteria strains of Lactobacillus buchneri, Lactobacillus plantarum, Lactobacillus brevis I and Lactobacillus acidophilus I were identified using API 50 CHL Kit and five various others of Lactobacillus paracasei DSM 2649, Lactobacillus buchneri DSM 20057T, Lactobacillus parabuchneri DSM 57069, Lactobacillus paracasei DSM 20020 and Lactobacillus farcimini CIP 103136T using MALDI-TOF/MS. Cell-free supernatant extracted from Lactobacillus plantarum, Lactobacillus buchneri, Lactobacillus brevis I and Lactobacillus acidophilus I included strong inhibitory effects against Vibrio cholera O1 (Inaba type), Vibrio cholera O139 (Bengal type), Vibrio parahaemolyticus ATCC 17802, Escherichia coli ATCC 11795, Escherichia coli O157, Salmonella typhimurium ATCC 14028 and a total of 23 serotypes of Salmonella spp. associated with outbreaks of food poisoning from raw chicken, egg shell and water samples. Only Lactobacillus buchneri DSM 20057T was identified by MALDI-TOF/MS as a strain producing sorbic and benzoic acids. This strain can potentially be used as food preservative to decrease growth of foodborne pathogenic bacteria

Effects of different extenders, cryoprotectants, equilibration and vapour exposure on freezability of African catfish(Clarias gariepinus) sperm / Noor Azlina Kamaruding

The aim of this study was to develop an optimal freezing protocol for African catfish(Clarias gariepinus) sperm with special reference to type of extender and cryoprotectant, molarity, equilibration duration, vapour temperature and vapour exposure duration. Using Tris-Citric Acid Yolk Extender (TCAYE), a 3x3x3x3 factorial experiment was carried out consisting of 3 molarities of glycerol (0.5, 1.0 and 2.0 M), 3 equilibration durations (120,140 and 160 minutes), 3 vapour temperatures (-80, -90 and -100oC) and 3 vapour exposure durations (5, 10 and 15 minutes). In addition, using Fish-Ringer Extender (FRE), a 3x3x3 factorial experiment was also conducted involving 3 equilibration durations (120, 140 and 160 minutes), 3 vapour temperatures (-80, -90 and -100oC) and 3 vapour exposure durations (5, 10 and 15 minutes). The molarity of cryoprotectant in FRE extender was fixed at 10% DMSO. Briefly, the straws containing the sperm were placed in refrigerator at 4oC with the fixed equilibration duration after which exposed to liquid nitrogen vapour at the fixed vapour temperature with the fixed vapour exposure duration. Subsequently, the straws were directly plunged into liquid nitrogen. The frozen sperm were thawed at 30oC for 30 seconds to evaluate the sperm motility characteristics using the automated semen analyzer (IVOS; Hamilton Thorne, USA). The effects of factors and parameters measured were analysed using Analysis of Variance (ANOVA) followed by Duncan Multiple Range Test (DMRT). In Experiment 1, large body weight (BW) of African catfish gave the highest fresh sperm total motility (82.40±4.59%) followed by medium BW (51.64±9.82%) and small BW (40.40±12.16%), whereby small BW fish were significantly different in total motility compared with the other two groups studied. In Experiment 2, glycerol with molarity of 0.5 M showed significantly the highest value of frozen-thawed sperm total motility (32.27±2.05%) as compared to 1.0 M (24.50±1.81%) and 2.0 M (2.63±0.29%). At 140 minutes equilibration duration, the value of total motility (31.69±2.19%) was 24 significantly higher as compared to 120 minutes (25.26±1.76%). There were no significant differences (P>0.05) in value of total motility for -80, -90 and -100oC which were ranged from 25.95±2.34% to 29.41±1.69%. The value of total motility did not show any significant differences (P>0.05) among the three vapour exposure durations (5, 10 and 15 minutes), which were ranged from 27.63±2.02% to 28.45±2.14%. In Experiment 3, there were no significant differences (P>0.05) in values of total motility at 120 minutes(76.65±2.27%) and 160 minutes equilibrations (76.01±2.04%), but these durations gave comparatively higher values of total motility than 140 minutes (66.90±2.60%). The values of total motility for vapour temperatures of -90oC (74.07±2.02%) and -100oC (74.95±1.88%) did not show any significant differences (P>0.05), but they were significantly different with -80oC, which gave comparatively lower values (64.59±5.08%).There were no significant differences (P>0.05) in values of total motility for 5, 10 and 15 minutes which were ranged from 72.67±2.27% to 73.99±2.34%. In Experiment 4, there were no significant differences (P>0.05) for values of total motility between 1.0 M(24.50±1.81%) and 2.0 M of glycerol in TCAYE (26.74±2.14%), but they were comparatively lower than 0.5 M of glycerol that showed higher significant value(32.27±2.05%). On the other hand, combination of DMSO (10%) in FRE extender showed the highest significant value of total motility (73.52±1.35%) as compared to the three molarities of glycerol in TCAYE extender. In summary, the best combination to obtain the highest frozen-thawed sperm motility characteristics for TCAYE extender was 0.5 M of glycerol, 140 minutes equilibration duration, -90oC vapour temperature and 5 to 15minutes vapour exposure duration, whereas for FRE extender was 120 minutes equilibration duration, -100oC vapour temperature and 5 to 15 minutes vapour exposure duration. In conclusion, results obtained in this study showed that 10% DMSO with FRE extender produced higher frozen-thawed sperm total motility than TCAYE extender.25 Future studies are needed through refinement in factors involved during freezing process that influence sperm survival before it can be used routinely in the reproduction of African catfish (Clarias gariepinus)