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Histopathological Observation of Aeromonas hydrophila Infection and Influences on Immune-related Enzyme Activity Indexes in Carassius auratus indigentiaus subsp. Nov.
Get PDFBacterial sepsis caused by Aeromonas hydrophila infection is one of the most common infectious diseases of Carassius auratus indigentiaus subsp. Nov. It has characteristics of quick onset, high morbidity, and high mortality. Bacterial sepsis has become an important constraint against the industrialization of aquaculture of Carassius auratus indigentiaus subsp. Nov. In this study, Carassius auratus indigentiaus subsp. Nov. were immersed in 1.0×109 CFU/mL Aeromonas hydrophila for infection, the cumulative mortality at 1d, 3d, 5d, 7d and 14d were 10%, 26.67%, 40%, 40% and 40%, respectively. After being challenged with Aeromonas hydrophila, hemorrhage focus and suppuration were observed on the body surface, pelvic fin, anal fin, and tail fin base of Carassius auratus indigentiaus subsp. Nov. Dissecting Carassius auratus indigentiaus subsp. Nov., blackening of the spleen and hemorrhage at the liver were discovered at 3d after being infected with Aeromonas hydrophila. Through tissue section observation, liver tissue was found to have to hemorrhage focus, and vacuolated liver cells, accompanied by inflammatory cell penetration. Inflammatory cell infiltration was also observed in spleen tissues and was most serious at 3d day after infection. After being infected with Aeromonas hydrophila, the gill filaments of Carassius auratus indigentiaus subsp. Nov. were deformed and shortened, gill filament cells fell off, intestinal villi are shortened and mucus cells are increased. After Aeromonas hydrophila infection to Carassius auratus indigentiaus subsp. Nov., the lysozyme content and activities of catalase, alkaline phosphatase, and total superoxide dismutase (T-SOD) in the liver began to increase significantly after the first day and reached a peak on the third day. However, they began to decrease gradually on the fifth day. The acid phosphatase (ACP) activity increased dramatically after the first day, peaked on the fifth day, and then decreased on the seventh day. It is speculated that such changes were attributed to the following two aspects: 1) On the one hand, Aeromonas hydrophila infection stimulates the nonspecific immune system of Carassius auratus indigentiaus subsp. Nov. 2) On the other hand, lesion of tissues occurs after Aeromonas hydrophila infection of Carassius auratus indigentiaus subsp. Nov. reaches a certain extent, thus influencing lysozyme content and the catalase activities, ACP, alkaline phosphatase and T-SOD in the liver
The effects of different stocking densities and feed types on frogs' growth and survival rates (Rana tigerina Dubois, 1981) reared in composite tanks
Get PDFWe performed two independent experiments, each with a completely random design in three repetitions and lasting 80 days, on the growth and survival of the artificially reared Thailand frog (Rana tigerina Dubois, 1981). Experiment 1 compared three stocking densities: 75 (D75), 100 (D100), and 125 (D125) individuals m−2. Experiment 2 used a stocking density of 100 individuals m−2 to study the effects of different feed types: frog feed, snakehead fish feed, catfish feed, and tilapia feed. Daily weight gain (DWG) and specific growth rate (SGR) did not differ between D75, D100, and D125, but these parameters tended to be higher at D100. At the end of the experiment, the average final weight and survival rate in D75 (204.59 ± 35.4 g and 79.67 ± 4.04%) and D100 (215.05 ± 38.65 g and 79.00 ± 2.75%) were not different, but both were significantly higher than those in D125 (184.64 ± 37.75 g and 57.00 ± 6.56%). In addition, frogs fed snakehead fish feed showed the highest DWG, SGR, and yield and the lowest feed conversion ratio (FCR), followed by frogs given frog feed, tilapia feed, and catfish feed, which showed decreasing yields and increasing FCR. In conclusion, a stocking density of 100 individuals m−2 using snakehead fish feed is suitable for rearing the Thailand frog under our experimental conditions
Association analysis of alpha-amylase (AMY) and cathepsin L (CTSL) SNPs with growth traits in giant tiger shrimp Penaeus monodon
Get PDFAlpha-amylase (AMY) and cathepsin-L (CTSL) were selected as candidate genes for SNP discovery for growth traits of P. monodon. Six SNPs were found in AMY and three in CTSL in P. monodon. Association analyses for the candidate SNPs with important economic traits were performed in populations. That allele A at CTLS-213 SNP, AA, and GA, tended to be associated with increased body weight. Shrimps with genotype GG had significantly smaller CL, CW, and CH values than those with GT and TT genotypes (P < 0.05). While CTLS-820 SNP was found to be significantly associated with CH and FSL (P <0.05). These SNPs will be valid for marker-assisted selection breeding programs in P. monodon
17α-Methyltestosterone enhances growth and reproductive performance of immature male Asian catfish (Clarias macrocephalus)
Get PDFThis study aimed to assess the effects of 17α-methyltestosterone (MT) on the growth and reproductive performance of male Asian catfish (Clarias macrocephalus). A total of 36 immature male Asian catfish (ABW = 125.97 g) were randomly distributed into 12 circular tanks, and fed with either the control diet (with no MT) or diets containing MT at 60 mg·kg-1, 90 mg·kg-1, or 120 mg·kg-1 for 45 days. Results showed that weight gain (WG), specific growth rate (SGR) and feed intake (FI) were significantly higher in the male catfish fed with diets containing 60 and 90 mg·kg-1 MT than in those fed with the control diet. Also, the diet attractability test revealed that the 60 and 90 mg·kg-1 MT groups significantly attracted more catfish than did the control diet; however, increasing MT to 120 mg·kg-1 reduced its attractability to the immature male catfish. MT-treated male catfish exhibited significantly heavier and significantly longer testes than male catfish fed the control diet at the termination of the feeding trial. These male catfish also exhibited significantly higher gonadosomatic indices (GSI) than catfish in the control group. Following induced spawning of nontreated female catfish and artificial fertilization of its eggs using testis preparation from the experimental male catfish at the termination of the feeding trial, results showed that testis preparations from all MT-treated males resulted in significantly higher fertilization (FR) and hatching rates (HR) of the eggs. In conclusion, incorporating MT to the diet improved both the growth and reproductive performance of the male Clarias macrocephalus. Precisely, dosages of optimal dietary MT using a quadratic model for maximal SGR, GSI, FR, and HR values were estimated to be 58.3, 75.0, 90.6, and 78.2 mg·kg-1, respectively
Report on the 9th International Conference on Austroasiatic Linguistics (ICAAL9) at Lund University, Sweden, November 18–19, 2021
Get PDFThis is a report on the 9th International Conference on Austroasiatic Linguistics (ICAAL9) at Lund University, Sweden, November 18–19, 2021, as well as a summary of the history and future plans of ICAAL
