Evaluation of growth performance and nutritional quality of diets using digestive enzyme markers and in vitro digestibility in Siamese fighting fish (Betta splendens Regan, 1910)

Digestive enzymes and their effects on in vitro digestibility of feeds and feedstuffs, as well as on growth performance quality were studied in Siamese fighting fish (Betta splendens Regan, 1910). The specific activities of total protease, amylase, trypsin and chymotrypsin increased during development and were higher in females than in males at maturation (P < 0.05). The activity ratio of trypsin to chymotrypsin corresponded to fish growth, and showed lower values in females than in males. White muscle levels of RNA decreased during development, with females having higher levels than males, while the protein levels increased with no difference between sexes. In the oocytes, trypsin-like and chymotrypsin-like specific activities were very low, and the concentrations of RNA, protein and protein/lipid ratio were higher than in the muscle. For in vitro digestibility, wheat gluten, soybean meal and fish meal were among good protein sources while the meals from peanut, fish and soybean were good carbohydrate sources. Golden apple snail meat was a good source for both protein and carbohydrate. The crude enzyme extracts from different growth stages and sexes had different abilities to digest the same feeds and feedstuffs. This will make it possible to preliminarily study the authenticated nutritional quality of raw materials for future feed formulations for B. splendens.Keywords: Betta splendens, digestive enzymes, feedstuff, in vitro digestibility, muscle quality, oocyte quality, Siamese fighting fishAfrican Journal of Biotechnology Vol. 12(14), pp. 1689-170

Diversity, biogeography and conservation of freshwater mussels (Bivalvia: Unionida) in East and Southeast Asia

Recent research efforts have significantly advanced our knowledge on Asian freshwater mussel (Bivalvia: Unionida) diversity and distribution. Here we provide a modern consensus of the diversity, biogeography and conservation of Unionida in the region comprising East and Southeast Asia (excluding Wallacea) and Asian Russia. A data review confirmed the presence of 228 native and 3 non-native Unionida (98% Unionidae, 2% Margaritiferidae), rendering the region a global hotspot of freshwater mussel diversity. Species richness was highest in China (particularly Yangtze basin) in absolute numbers and Cambodia when correcting for country area, and decreased gradually towards the south and steeply towards the north and east. Six of the seven unionid subfamilies are native to the region, with species richness peaking in Southeast Asia for Rectidentinae, Gonideinae, Parreysiinae and Modellnaiinae, China for Anodontinae and Unioninae, and Asian Russia for Margaritiferidae. Conservation status and data collected after 1980 were not available for 61 and 24% of species, respectively. Dams, deforestation and pollution are likely the major threats to mussels in the region, though data in this respect are scarce. The Philippines, Laos, Indonesia, Myanmar and Malaysia are among the countries with the poorest data availability and urgently require research.AZ was supported by a Postdoctoral Research Fellowship by the School of Environmental and Geographical Sciences, University of Nottingham Malaysia Campus. EF was supported by the Portuguese Foundation for Science and Technology (FCT) under grant SFRH/BPD/ 108445/2015

Mesozoic mitogenome rearrangements and freshwater mussel (Bivalvia: Unionoidea) macroevolution

© 2019, The Author(s), under exclusive licence to The Genetics Society. Using a new fossil-calibrated mitogenome-based approach, we identified macroevolutionary shifts in mitochondrial gene order among the freshwater mussels (Unionoidea). We show that the early Mesozoic divergence of the two Unionoidea clades, Margaritiferidae and Unionidae, was accompanied by a synchronous split in the gene arrangement in the female mitogenome (i.e., gene orders MF1 and UF1). Our results suggest that this macroevolutionary jump was completed within a relatively short time interval (95% HPD 201–226 Ma) that coincided with the Triassic–Jurassic mass extinction. Both gene orders have persisted within these clades for ~200 Ma. The monophyly of the so-called “problematic” Gonideinae taxa was supported by all the inferred phylogenies in this study using, for the first time, the M- and F-type mitogenomes either singly or combined. Within Gonideinae, two additional splits in the gene order (UF1 to UF2, UF2 to UF3) occurred in the Mesozoic and have persisted for ~150 and ~100 Ma, respectively. Finally, the mitogenomic results suggest ancient connections between freshwater basins of East Asia and Europe near the Cretaceous–Paleogene boundary, probably via a continuous paleo-river system or along the Tethys coastal line, which are well supported by at least three independent but almost synchronous divergence events

Research priorities for freshwater mussel conservation assessment

Freshwater mussels are declining globally, and effective conservation requires prioritizing research and actions to identify and mitigate threats impacting mussel species. Conservation priorities vary widely, ranging from preventing imminent extinction to maintaining abundant populations. Here, we develop a portfolio of priority research topics for freshwater mussel conservation assessment. To address these topics, we group research priorities into two categories: intrinsic or extrinsic factors. Intrinsic factors are indicators of organismal or population status, while extrinsic factors encompass environmental variables and threats. An understanding of intrinsic factors is useful in monitoring, and of extrinsic factors are important to understand ongoing and potential impacts on conservation status. This dual approach can guide conservation status assessments prior to the establishment of priority species and implementation of conservation management actions.NF-R was supported by a post-doctoral fellowship (Xunta de Galicia Plan I2C 2017-2020, 09.40.561B.444.0) from the government of the autonomous community of Galicia. BY was supported by the Ministry of Science and Higher Education (no. 0409-2016-0022). DLS was supported by the G. E. Hutchinson Chair at the Cary Institute of Ecosystem Studies. AO was supported by the Russian Foundation for Basic Research (no. 17-44-290016). SV was funded by European Investment Funds by FEDER/COMPETE/POCI- Operacional Competitiveness and Internacionalization Programme, under Project POCI-01-0145-FEDER-006958 and National Funds by FCT-Portuguese Foundation for Science and Technology, under the project UID/AGR/04033/2013. NF-R is very grateful to the University of Oklahoma Biological Survey for providing space to work in the U.S. and especially to Vaughn Lab members. Authors are very grateful to Akimasa Hattori, Allan K. Smith, Andrew Roberts, Daniel Graf, David Stagliano, David T. Zanatta, Dirk Van Damme, Ekaterina Konopleva, Emilie Blevins, Ethan Nedeau, Frankie Thielen, Gregory Cope, Heinrich Vicentini, Hugh Jones, Htilya Sereflisan, Ilya Vikhrev, John Pfeiffer, Karen Mock, Mary Seddon, Katharina Stockl, Katarzyna Zajac, Kengo Ito, Marie Capoulade, Marko Kangas, Michael Lange, Mike Davis, Pirkko-Liisa Luhta, Sarina Jepsen, Somsak Panha, Stephen McMurray, G. Thomas Watters, Wendell R. Haag, and Yoko Inui for their valuable contribution in the initial selection and description of extrinsic and intrinsic factors. We also wish to thank Dr. Amanda Bates, Chase Smith, and two anonymous reviewers for comments on earlier drafts of this manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government

Effects of different modified diets on growth, digestive enzyme activities and muscle compositions in juvenile Siamese fighting fish (Betta splendens Regan, 1910)

The effects of four modified diets (gamma-irradiated, microwave-irradiated, probiotic-supplemented and carbohydrase-supplemented diets) were studied on digestive enzyme specific activities and growth performance quality of juvenile Siamese fighting fish (Betta splendens Regan, 1910) during 2 weeks of critical and intensive rearing period. The modified procedures did not change biochemical compositions and gross energy of diets, but generally resulted in relatively higher in vitro digestibilities of protein and carbohydrate and fish survival rate, albeit insignificant. Only gamma irradiation significantly increased in vitro protein digestibility of the diet, and microwave irradiation increased starch gelatinization and water solubility (Pb0.05). Fish fed microwave-treated diet showed highest values in all studied growth indicators and digestive enzyme specific activities (except lipase), with significantly higher amylase specific activity and activity ratio of amylase to trypsin (A/T ratio). Correlation analysis indicated significant relationships (Pb0.05) among the levels of total protease, amylase and trypsin, and between SGR and A/T ratio. Muscle and body compositions of juveniles fed on microwave- or gamma-irradiated diets were similar to the control, while the juveniles fed on probiotic- or carbohydrase-supplemented diets showed lower protein depositions (Pb0.05). Similar levels of RNA, RNA/Protein ratio, and Protein/Lipid ratio in body andmuscle in all dietary groups fed ad libitumsuggested that the improved growth performance in juvenile Siamese fighting fish fed on microwave-irradiated diet may not be only due to improved physicochemical properties of the diet but also improved fish consumption rate

Temperature and pH Characteristics of Amylase and Lipase at different developmental stages of Siamese fighting fish (Betta splendens Regan, 1910)

Temperature (20-80°C) and pH (2-12) profiles of amylase and lipase at three stages (10-dayold, 1.5-month-old and 3-month-old) in Siamese fighting fish Betta splendens Regan, 1910) were studied. At least nine amylase activities were observed during development: pH 7 at 40°C, pH 9 at 30°C and 50° C, pH 8 and pH 11 at 50°C in females and pH 8 and pH 11 at 40°C and 60°C in males. At the younger stage (≤ 1.5 month old), activity at pH 7 and 40°C, and at pH 9 and 30°C and 50°C was observed. At the older stage (≥ 1.5 month old), amylase activity at pH 8 and pH 11 in the temperature range of 40-60°C was found. Lipase had at least five levels of activity: pH 7 at 20°C and 40°C, pH 8 at 20-40°C and 60°C, and at pH 11, where the activity peak disappeared in the maturing stage (3 month old) in both sexes. Amylase had very low specific activity at the 10-day-old stage, while lipase had a high specific activity, similar to older stages. The most suitable pH to determine amylase and lipase activity in Siamese fighting fish was pH 8, whereas a temperature of 50°C was appropriate for amylase and 40°C was suitable for lipase, regardless of sex and age. This information is a prerequisite for future studies of the in vitro digestibility evaluation of nutrient utilization in Siamese fighting fish