10.P4. Physiological responses of fish, Piaractus mesopotamicus, to infection with the freshwater fish louse, Dolops carvalhoi

Trichodinids are mobile peritrichous ciliated protozoa, and widely known as ectocommensals and/or parasites of fish andother aquatic organisms. Little is known about the trichodinid fauna in Brazilian fish. This study reports Trichodina het-erodentata Duncan, 1977 as a new parasite for freshwater fish Piaractus mesopotamicus Holmberg, 1887. This is the firstrecord of this trichodinid in southeastern Brazil. Fifty specimens impregnated with 2% silver nitrate and another fiftystained with Giemsa were used for morphometry on the taxonomic characteristics. T. heterodentata in this study is medi-um size, with a disc-shaped body measuring 49.0 to 61.0 µm, parasitizing the skin, fins and gills of pacu. Measurement comparisons between the present material and other records from different countries are presented.

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Growth, survival and bone alterations in Piaractus mesopotamicus larvae under different rearing protocols

Ciência Rural ◽

10.1590/0103-8478cr20141139 ◽

2015 ◽

Vol 45 (9) ◽

pp. 1667-1673

Author(s):

David Roque Hernández ◽

Carlos Hernán Agüero ◽

Juan José Santinón ◽

Alfredo Oscar González ◽

Sebastián Sánchez

Keyword(s):

Growth Rate ◽

Freshwater Fish ◽

Experimental Period ◽

Average Weight ◽

Important Species ◽

Piaractus Mesopotamicus ◽

Morphological Alterations ◽

Skeletal Malformations ◽

Osteological Development ◽

Experimental Treatments

The pacu (<bold>Piaractus mesopotamicus</bold>) is a neotropical freshwater fish. It is one of the most important species farmed in areas of the Parana and Paraguay Rivers basins. The effects of different rearing protocols on growth, survival and incidence of skeletal malformations in pacu larvae were analyzed. A total of six experimental treatments were considered, consisting of: a semi-intensive larviculture (LS) in ponds; intensive larviculture (LIn) in laboratory (both LS and LIn until 60 days of life); and mixed larviculture, with 20 days of semi-intensive larviculture into cages in ponds after 14 (L1), 21 (L2), 33 (L3) or 40 (L4) days of laboratory larviculture. At the end of the experimental period, LSlarvae showed higher growth rate, with average weight values (2.28g) and total length (TL-48.20mm) statistically higher than the rest (P<0.05). L1 to L4 treatments showed intermediate growth values, without differences between them (P>0.05), while LIn presented the lowest growth (P<0.05). Survival was around 75% in all experimental groups, except LS, that presented a significantly lower value (17.5%, P<0.05). Skeletal abnormalities were detected in all experimental treatments, but LIn and L1 presented the lowest incidence. In no case, visible morphological alterations were found. This study shows that prolonging pacu rearing under laboratory conditions at high densities improves temporal availability and survival of juvenile without affecting growth or subsequent osteological development of fish.

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Vitellogenesis and other physiological responses induced by 17-β-estradiol in males of freshwater fish Rhamdia quelen

Comparative Biochemistry and Physiology Part C Toxicology & Pharmacology ◽

10.1016/j.cbpc.2009.11.002 ◽

2010 ◽

Vol 151 (2) ◽

pp. 248-257 ◽

Cited By ~ 15

Author(s):

D.D. Moura Costa ◽

F. Filipak Neto ◽

M.D.M. Costa ◽

R.N. Morais ◽

J.R.E. Garcia ◽

...

Keyword(s):

Freshwater Fish ◽

Physiological Responses ◽

Rhamdia Quelen

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Physiological Responses of Largemouth Bass, Micropterus salmoides, Exposed to Salinity

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f90-262 ◽

1990 ◽

Vol 47 (12) ◽

pp. 2358-2363 ◽

Cited By ~ 20

Author(s):

M. R. Meador ◽

W. E. Kelso

Keyword(s):

Osmotic Stress ◽

Ion Transport ◽

Freshwater Fish ◽

Largemouth Bass ◽

Laboratory Experiments ◽

Micropterus Salmoides ◽

Physiological Responses ◽

Plasma Chemistry ◽

Elevated Plasma ◽

Active Ion Transport

Plasma osmotic and electrolyte concentrations as well as branchial Na+/K+ and Mg++ ATPase activities were determined in the field for largemouth bass, Micropterus salmoides, from a brackish marsh and freshwater lake in southcentral Louisiana. Laboratory experiments were conducted to evaluate plasma chemistry and gill ATPase activities of largemouth bass from both locations exposed to 0, 4, 8, and 12‰ salinity. No significant differences in physiological responses were detected between marsh and freshwater largemouth bass exposed to 0, 4, or 12‰. Exposure to 12‰ salinity resulted in osmotic stress in largemouth bass from both locations. At 8‰, marsh largemouth bass had significantly higher plasma solutes and lower gill ATPase activities than freshwater fish. Different physiological responses by marsh and freshwater largemouth bass during exposure to 8‰ salinity indicated that marsh largemouth bass have adapted to environments of variable salinity by reducing active ion transport and tolerating elevated plasma son levels.

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