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An eight-week investigation was conducted to access the potential impact of dietary watermelon rind powder (WMRP) and L. plantarum CR1T5 (LP) administered individually or in combination on immunity, disease resistance, and growth rate of Nile tilapia fingerlings cultured in a biofloc system. Three hundred twenty fish (average weight 16.57 ± 0.14 g) were distributed into 16 tanks at a rate of 20 fish per tank. The fish were fed different diets: Diet 1 (0 g kg−1 WMRP and 0 CFU g−1 L. plantarum) (control), Diet 2 (40 g kg−1 WMRP), Diet 3 (108 CFU g−1 LP), and Diet 4 (40 g kg−1 WMRP + 108 CFU g−1 LP) for eight weeks. A completely randomized design (CRD) with four replications was applied. Skin mucus, serum immunity, and growth parameters were analyzed every 4 weeks, and a challenge study against S. agalactiae was conducted at the end of the experiment. The findings showed that the inclusion of WMRP + LP, administrated individually or in a mixture, significantly (P

The present study aimed to investigate the effects of dietary Spirulina (Arthrospira platensis) supplementation on the growth, survival, haematology, immune parameters and disease resistance of Rugose frog (Hoplobatrachus rugulosus) against Aeromonas hydrophila infection. Frogs were fed a formulated diet containing Spirulina as 0% (control), 1.5%, 3.0%, 4.5%, and 6.0% for a period of eight weeks. The results indicated that growth parameters; final body weight, weight gain, average daily gain, specific growth rate, feed conversion ratio, and survival rate of frog fed with A. platensis at the level of 4.5% showed best values but not significantly different (P>0.05). However, haematological values; leukocytes, erythrocytes, haemoglobin, and haematocrit levels were highest and significantly different (P

This research was aimed to study on biological aspects of giant snakehead fish (Channa micropeltes) in Huai Suea Ten wetland site, Nam Phong District, Khon Kaen Province in Thailand between April, 2017 and March, 2018. Thirty-six fish species belonging to 17 families were observed at 10 sampling sites. Three Channidae fishes, namely snakehead fish (Channa striata), giant snakehead fish (Channa micropeltes), and forest snakehead fish (Channa lucius), belonging to the family Channidae were reported. A total of 230 giant snakehead fish were found in this survey which consisted of 118 males and 112 females. The sex ratio (male: female) was 1:0.95. The gonadosomatic index value of the female (0.79±0.05%) was higher than that of the male (0.25±0.08%). The body length and body weight of a total of 230 giant snakehead fish observed in this study showed the average of a total body length was 43.71±11.72 cm; and the average of the body weight was 448±173 g/fish. The condition factor of giant snakehead fish observed in 12 months were in a range of 0.45-0.74 for the male and 0.39-0.70 for the female. The ratio of the body and intestinal length of giant snakehead fish was as 1: 0.70. The stomach digesta components, expressed as the percentages of a whole stomach content weight of this fish species consisted of 51.8% of fish fillet, 30.3% of small fish and 17.9% of digested digesta.

This study aims to develop an alternative field-based approach to interrupt the life cycle of O. viverrini. The effects of temperature, salinity, acidity, ultraviolet A, B, C radiation, and combinations of these physicochemical factors on the loss of infectivity of Opisthorchis viverrini cercariae were analyzed to determine values required for 50 and 95 % lethal concentrations (LC50 and LC95) and period of loss infection success (LI50 and LI95). Newly shed cercariae of O. viverrini were used. LC50 and LC95 values for temperature, salinity, and acidity on cercariae were 33.19 and 37.70 ºC, 7.29 and 8.40 ppt, 4.62 and 4.80 M H2CO3, respectively. The values of LI50 and LI95 on cercariae by exposure to UVA, UVB, and UVC were 19.54 and 20.11 h, 5.03 and 5.12 h, 3.37 and 6.02 min, respectively. Combinations of these factors in the presence of UVC proved damaging to cercariae most rapidly. The shortest loss infection time of LI50 and LI95 were 1.09 and 2.83 min. Cercariae were deemed to have lost the ability to infect cyprinid fish when they had shed their tails, even though they were still capable of some movement. In nature, temperature, salinity, acidity, ultraviolet radiation, and combinations of these factors, affect the ability of O. viverrini cercariae to infect cyprinid fish.

The diversity of fish parasites from freshwater fishes collected from the Nong Han wetland (Udon Thani Province, Thailand) was studied by visually examining 22 freshwater fish species (253 samples) from 19 genera for external and internal parasites. A majority of fishes in the Nong Han wetland were infected by parasites (75.89%). Twenty fish species (75.89%) were infected with a total of 29 species of parasites. These included 9 species of monogeneans, 5 crustaceans, 5 acanthocephalans, 4 nematodes, 3 digeneans, and 3 species of cestodes. Cyclocheilichthys apogon had the most diverse parasite community (8 species). Seasons affected the prevalence and mean intensity of parasitic infection; the prevalence was highest during the rainy (85.54%) and winter (84.75%) seasons, and lower during the summer (63.96%) season. Fish diversity and parasite diversity exhibited a positive correlation relationship. In the light of declining fish populations in the Nong Han wetland, this study may provide critical information for the sustainable management of this wetland. Furthermore, some of the identified fish parasites can be harmful to humans if fish is eaten raw or improperly cooked, as is the tradition in northeastern Thailand, so our findings may bear relevance for public health workers as well.

Two experiments were conducted at Khon Kaen University, Nong Khai campus, Thailand during May to December 2015 to justify effects of chitosan of Experiment 1 on growth performance of rice-field crabs. The Experiment 1 had five chitosan treatments, i.e. 0, 1, 2, 3 and 4 % (on dry matter basis). Experiment 2 had two treatments, i.e. the best treatment of Experiment 1 (T3) was chosen in comparison with flesh fish meat treatment. A Completely Randomized Design (CRD) with four replications was used for Experiments 1 and 2. The results of the Experiment 1 showed that a chitosan level of 2 % of T3 gave significantly (p < 0.05) better growth performance on final weight gained, weight gained, average daily growth rate, specific growth rate and survival rate (%) of the rice-field crabs than the rest, except that of the feed conversion ratio where T1 (control) was the highest. Thus a chitosan level of 2 % (T3) in the feed diet is recommended for rice-field crab culture. With the Experiment 2, the feed diet of T3 of Experiment 1, i.e. with 2 % chitosan gave significantly (p < 0.05) higher survival rate (%) of rice-field crabs than the flesh fish meat of T1.

The optimal level of dietary moringa leaf was determined on the growth performance, feed utilization, digestibility and serum biochemistry of Bocourti's catfish with mean wet weights of 3.72 ± 0.06 g per fish. Fish were fed with diets containing isonitrogenouse (350 g/kg crude protein) and isoenergetic (3000 kcal/kg) supplemented with dietary moringa leaf at 0 g/kg fish, 100 g/kg fish, 150 g/kg fish and 200 g/kg fish for 60 d. Fish were hand fed to apparent satiation twice a day. At the end of the experiment, a significant (p 0.05). The study indicated that dietary moringa leaf could be included in the Bocourti's catfish diet at possibly not over 100 g/kg fish without a negative effect on the growth, feed utilization, digestibility and serum biochemistry.

Opisthorchis viverrini is an important public health problem, a major cause of cholangiocarcinoma in the Greater Mekong subregion including Lao PDR, Cambodia, Vietnam and Thailand. Humans acquire the infection by consumption of raw, fermented or partially cooked freshwater cyprinid fish containing infective metacercariae. This study examined the effect of cercarial infection dosage (25-200 cercariae), age (1-60 day) and size (1-24mm) of Barbonymus gonionotus fish on infection success of O. viverrini cercariae. Additionally, the site of cyst formation of O. viverrini cercariae and subsequent development to the metacercariae was examined. The result showed that cercarial infection dose (F4,95=8.52, P

Objective To explore larvicidal effects of anthelmintic drugs on Opisthorchis viverrini (O. viverrini) for alternative approach to interrupting its cycle for developing a field-based control program. Methods The larvicidal activities of albendazole (Al), artesunate (Ar), praziquantel (Pzq) and miltefosine (Mf) on O. viverrini cercariae and mature metacercariae were investigated. Lethal concentrations (LC50 and LC95) of these drugs were determined. Mature metacercariae previously exposed to various concentrations of the drugs were administered to hamsters. Worms were harvested 30 d post infection and worm recovery rates calculated. Al, Ar, Pzq and Mf produced morphological degeneration and induced shedding tails of cercariae after 24 h exposure. Results The LC50 and LC95 of Al, Ar, Pzq and Mf on cercariae were 0.720 and 1.139, 0.350 and 0.861, 0.017 and 0.693, and 0.530 and 1.134 ppm, respectively. LC50 and LC95 of Ar on mature metacercariae were 303.643 and 446.237 ppm and of Mf were 289.711 and 631.781 ppm, respectively but no lethal effect in Pzq- and Al-treated groups (up to 1 ppt). No worms were found in hamsters administered Pzq-treated metacercariae. The adult worms from Al-treated metacercariae were significantly bigger in size compared to the control group (P Conclusions The larvicidal effects of these drugs were high efficacy to O. viverrini cercariae but lesser efficacy to metacercariae. It should be further studied with the eventual aim of developing a field-based control program.

Opisthorchiasis caused by Opisthorchis viverrini infection, is a serious public health problem in Lao PDR, Cambodia, Vietnam and Thailand. Cyprinid fish are required for the transmission of O. viverrini metacercariae to fish eating-mammal hosts including humans. The transmission of infective metacerariae is an important event, potentially resulting in the development of cholangiocarcinoma in cases of chronic opisthorchiasis. For a better understanding of the development of O. viverrini metacercariae in the second intermediate host, Barbonymus gonionotus (Cyprinidae), the immune response of infected B. gonionotus through fibrous tissue formation and superoxide dismutase (SOD) activity were investigated. The immunosuppressant (prednisolone) was administered to B. gonionotus infected with O. viverrini cercariae to study infectivity and development of the metacercariae. Additionally, the effects of prednisolone were studied by the investigation of fibrous tissue formation around the metacercariae, as well as SOD activity. In our study, prednisolone administered prior to infection in B. gonionotus had higher metacercarial recovery when compared to the non-administered control group. On the other hand, the administration of prednisolone after the O. viverrini infection allowed metacercariae to develop to the infective stage. Energy consumption from encystation to the infective stage required 443.9-463.7degree-days. The results show that immunosuppression decreases fibrous tissue and SOD activity in infected fish, and also affects the ability of O. viverrini metacercariae to develop to the infective stage. The immune response to metacercarial development of O. viverrini in cyprinid fish should be further studied to gain a greater understanding of this process, and hence, a better understanding of the mechanism(s) involved in metacercarial wall formation.