Pseudolaguvia moinensis, a new benthic miniature Asian catfish (Teleostei: Sisoridae) from Arunachal Pradesh, north-eastern India

A new species of miniature sisorid catfish is described, from the upper Brahmaputra river drainage in northeastern India. The new species is distinguished from all its congeners except P. ferruginea and P. focusa by having an elongate light brown to cream marks either side on ventro-lateral margin just above anus. Further, distinguished from its congeners by the following combination of characters: presence of a W-shaped dark brown band on caudal fin, thoracic adhesive apparatus extending closer to pelvic-fin base, smooth anterior margin of dorsal spine, a narrow V-shaped light brown to cream bands on side of the body, dorsal-spine length (10.7-14.7% SL), dorsal-fin base length (10.7-14.2% SL), pectoral-fin spine length (14.0-21.1% SL), pelvic-fin length (13.5-16.6% SL), caudal peduncle length (14.4-18.2% SL) and depth (7.8-9.9% SL), total vertebrae (30-31), caudal fin with a complete medial hyaline bands towards its anterior end, reaching outer margin of each lobe. Other combination of characters differentiating the new species from its congeners are provided in the respective diagnoses.

Effects of Dietary Mannan Oligosaccharide on Growth Performance, Feed Utilization, Body Composition and Haematological Parameters in Asian Catfish (Clarias batrachus) Juveniles

The influence of dietary supplementation of mannan oligosaccharide (MOS) on growth performance, feed utilization, body composition and haematological parameters were evaluated in Asian catfish (Clarias batrachus) juveniles. Triplicate groups of juveniles Asian catfish (21.23 ± 1.01 g) were fed twice per day at 3 % of body weight for 12 weeks, with 0 (control), 0.2, 0.4 or 0.6% MOS diets. Compared to control, those fed with MOS supplemented diets had significantly improved (P<0.05) specific growth rates, protein efficiency ratio and survival rate. Significantly lower hepatosomatic index was noted in 0.2% and 0.4% MOS diets compared to those fish fed control. Similarly, intraperitoneal fat was significantly lowest in those fish fed with 0.4% diet over the control group. The highest protein content was (81.86±0.36) in fish fed with 0.4% MOS diet, whereas ash content was highest (7.33±1.23) in fish group fed with 0.6% MOS. Significantly decreased erythrocyte sedimentation rate and increased packed cell volume were observed when the fish fed with 0.4% and 0.6% MOS diets compared to the remaining treatments. MOS supplemented diets showed significant influence on the white blood cell count compared to the control. Thus, 0.4% MOS is sufficient to improve growth and haematological parameters in Asian catfish.

Seasonal Dynamics of Stomach Contents, Trophic Level, Length-Weight Relationship and Condition Factor of Mystus bleekeri (Day, 1877)

The Asian catfish Mystus bleekeri is a popular food fish along with favored as an ornamental fish in Bangladesh. Till now detailed report on stomach contents, trophic level, length-weight relationship and condition factor of this fish species in the agro-climatic context of Bangladesh is lacking. Hence, the aims of this study were to describe the stomach content, trophic level, length-weight relationship (LWR) and condition factors of Mystus bleekeri collected from Dekhar Haor, Sylhet, Bangladesh from July 2017 to June 2018. A total of 600 specimens ranging from 6.9-24.6 cm total length (TL) and 5.7-72.4 g body weight (BW) was analyzed in this study. Stomach content analysis showed that the fish fed mostly on Mollusca with a frequency of occurrence (fo: 25.36%) and worms (fo: 21.68%), followed by plant matters (fo: 3.32%), Cladocerana (fo: 1.18%), Copepoda (fo: 0.95%), and Teleostei (fo: 0.36%). The estimated mean trophic level (TROPH) ranged from 2.35±0.13 in December to 3.02±0.23 in August, indicating that they are opportunistic feeder. The LWR analysis showed negative allometric growth (b<3) throughout the year. The values of the exponent b in the LWR (W=aLb) vary between 1.474 and 2.490.The mean K value was significantly higher in October indicating the heavier weight and better condition of the fish (P<0.05). The data obtained from this study would be useful to introduce sustainable management of Mystus bleekeri not only in Dekhar Haor but also in other inland waters of Bangladesh.

Alterations of Stress Parameters and Histology of Asian Catfish (Pangasius hypophthalmus) in Transport

Stress parameter changes (cortisol, glucose, sodium and chloride) and histological alterations (gills, liver, kidney, and spleen) in Asian Catfish (Pangasius hypophthalmus) in transport were investigated. In this study, three separated trials were fulfilled. These were without tricaine, 40 and 60 mg L-1 of tricaine, respectively. Each trial consisted of 4 stages, control (C), transfer (AT), transport (TP) and recovery (24 h). After each stage, blood samples were taken and then, gills, liver, kidney, and spleen samples were collected for histological examination. In the transport without tricaine, the fish glucose increased from 50-60 mg dL-1 to 70-80 mg dL-1 and cortisol increased from 30 ng dL-1 to 90 ng dL-1 in. Sodium was 127-132 meq L-1 in the AT and TP, while 138 meq L-1 in the C and recovery. Cloride changed 103 meq L-1 in the TP, while approximately 107 meq L-1 in C, AT and recovery in the transport without tricaine. In the second trial, the fish glucose increased from 50-65 mg dL-1 to 80-90 mg dL-1 cortisol decreased from 60-70 ng dL-1 to 35-45 ng dL-1 in the transport with 40 mg L-1 of tricaine. Sodium was 130-140 meq L-1 in the C and recovery, while 125 meq L-1 in the AT and TP. Chloride was about 110 meq L-1 in the C, AT and recovery, while 102 meq L-1 in the TP in the transport with 40 mg L-1 of tricaine. In the third trial, the fish glucose was 40-55 mg dL-1 in the C, AT and TP, while 25-30 mg dL-1 in the recovery. Cortisol was 35-40 ng dL-1 in the C and AT, while 25 ng dL-1 in the TP and recovery. Sodium was 126-128 meq L-1 in the C, AT and recovery, while about 119-122 meq L-1 in the TP. Chloride was 110 meq L-1 in the C, AT and recovery, while 104-106 meq L-1 in the TP in the transport with 60 mg L-1 of tricaine. The end of the experiment, it is realized that the usage of the tricaine had positive effects on Asian catfish transport.

Potentially new emerging diseases on two species of Indonesian freshwater aquaculture: giant gourami (Osphronemus gourami) and Asian catfish (Pangasius hypophthalmus)

Disease outbreaks and mortality in giant gourami and Asian catfish (pangasius) culture have been frequently reported during the last decade. Etiological agents of the disease have remained unknown, so it is needed to explore epidemiological studies to know the main causative agents. The study aimed to know the main pathogenic agents who were identified during disease outbreaks on giant gourami and pangasius. Data and information were collected through active and passive surveillance at the production centers of each species. Analysis was carried out according to standard fish disease diagnosis and eventually was focused on two suspected new emerging diseases (NED), namely Infectious Spleen and Kidney Necrosis Virus (ISKNV) belonging to Megalocytivirus on giant gourami and Enteric Septicemia of Catfish (ESC) caused by Edwardsiella ictaluri on pangasius. The results showed that ISKNV was detected on most of the diseased giant gourami samples and that E. ictaluri was identified on most diseased pangasius samples. This study concluded that both pathogenic agents, Megalocytivirus and E. ictaluri were suspected to be potentially NED on freshwater aquaculture, especially infecting giant gourami and pangasius respectively.