Effects of ploidy and nutritional conditions on muscle morphology, proliferation and myogenic proteins expression in Rhamdia quelen larvae

Although Rhamdia quelen is a promising species for farming in South America, many aspects of its development and optimal conditions of culture remain unknown. In this sense, we explore muscle development and some proteins related to myogenic process in diploid and triploid larvae submitted to fasting-refeeding. Regarding muscle morphology, within diploid groups, fasted larvae (FD) showed a significant decrease in white muscle fiber area compared with control (CD) and refed (RD-1) groups. Then, when food was provided, area values restored nearly to control. Based on these results, it is probable that temporary muscle fiber atrophy takes place in fasted diploid fish. Conversely, no significant morphological changes were observed among triploid groups. When the effects of ploidy on somatic growth were assessed, FD and RT-1 groups registered a significantly higher percentage of fibers with an area smaller than 500 μm2 compared with fasted triploid larvae (FT) and RD-1 groups, respectively. Additionally, immunolocalization of the proliferating cell nuclear antigen (PCNA) decreased during starvation in fish of both ploidies and only recovered to normal after refeeding in triploid fish. An increase in PCNA related to ploidy was detected in CD and RD-1 compared with their triploid counterparts. In relation to myogenic proteins, Myog showed a significant increase expression in diploid larvae during starvation. Mstn was not affected by ploidy or alimentary variations. Our results show that diploid fish are more affected by short-term starvation than triploid fish, which could be indicative of differential physiological responses of diploid and triploid larvae to alimentary changes in culture. This might be relevant to optimize conditions of culture for both diploid and triploid fish.Fil: Boaglio, Andrea Carolina. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Cátedra de Histología y Embriología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mendía Broda, Andrea Cecilia. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Cátedra de Histología y Embriología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Muñoz, Lautaro H.. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias; ArgentinaFil: Mascambroni, Maria Belen. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias; ArgentinaFil: López, Pablo A.. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias; ArgentinaFil: Morón Alcain, Esteban. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias; ArgentinaFil: Arranz, Silvia Eda. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; ArgentinaFil: Vigliano, Fabricio Andrés. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Cátedra de Histología y Embriología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Effects of heat and cold shock-induced triploidy on productive parameters of silver catfish (Rhamdia quelen) late-hatched in the reproductive season

This study was carried out in order to assess the productive performance of triploids of silver catfish (Rhamdia quelen) obtained by heat (HT) and cold shock (CT) at the end of the reproductive season. In hatchery, HT larvae reached the highest survival rate since they exhibited the lowest cannibalism rate among all groups. Although mean weight of larvae in HT group was lower in comparison with CT and diploid counterparts, the final biomass of HT was the highest due to the great survival rate observed in this group. At the end of the fattening trial both HT and CT groups showed better productive parameters than diploid control group. The mean weight of HT and CT were significantly higher than diploids. The condition factor was significantly higher in HT in comparison with CT and diploid fish. However, only CT males and females showed significantly higher carcass weight than control fish. Also carcass yield was greater in triploid females although only CT males displayed significantly higher carcass yield than their diploid counterparts. The gonadosomatic index (GSI) exhibited a different pattern in each sex. In males, CT showed a significantly lower GSI in comparison with HT and diploid fish. Control females displayed the highest GSI with significant differences with both triploid groups. In addition, CT males and females accumulated significantly higher percentage of abdominal fat than their control counterparts. A strong negative correlation between GSI and carcass yield in females was observed. These results demonstrate that HT and CT of R. quelen exhibited superior productive parameters than control fish in both hatchery and fattening period. Since some variables assessed were better in HT while others were improved in CT group, the election of heat or cold shock-induced triploids for culture should be based on the productive aims of each fish farm.Fil: Morón Alcain, Esteban. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias; ArgentinaFil: Mendía Broda, Andrea Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Cátedra de Histología y Embriología; ArgentinaFil: Muñoz, Lautaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Cátedra de Histología y Embriología; ArgentinaFil: Boaglio, Andrea Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Cátedra de Histología y Embriología; ArgentinaFil: Cerutti Burbe, Pablo Adolfo. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias. Instituto de Ictiología del Nordeste; ArgentinaFil: Hernandez, David Roque. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias. Instituto de Ictiología del Nordeste; ArgentinaFil: López, Pablo Andrés. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias; ArgentinaFil: Vigliano, Fabricio Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias; Argentin