Abstract This study evaluated the growth performance and parasite load of angelfish juveniles Pterophyllum scalare kept at different stocking densities using two rearing systems. The experiment was ...conducted in a factorial design (4x2) with four stocking densities (0.1, 0.4, 0.7, and 1.0 g/L), two type of aquarium tanks (glass and ceramic aquariums), and four replicates. The experiment lasted 60 days using 148 juvenile fish (3.05 ± 0.09 g) randomly placed in 32 aquariums (50 L) equipped with filters and aeration. All fish received two meals a day ad libitum (8:00 and 16:00). Water quality parameters such as temperature, dissolved oxygen, pH, and total ammonia were measured. At the end of the experiment, all fish were measured and weighed to determine growth performance and then subjected to parasitological analysis. The data were analyzed with a two-way ANOVA with post-hoc Tukey test (p<0.05). No effects on growth performance at different stocking densities were observed. However, there was an increase in Capillaria pterophylli infestation in the high stocking density within ceramic aquariums. Thus, this study recommends the use of 1.0 g/L for the intensive aquaculture system of freshwater angelfish, and applying cleaning management to avoid parasite infestation, particularly in ceramic aquariums.
Resumo Este estudo avaliou o desempenho de crescimento e a carga parasitária de juvenis de peixe anjo Pterophyllum scalare mantidos em diferentes densidades de estocagem usando dois sistemas de criação. O experimento foi conduzido em esquema fatorial (4 x 2) com quatro densidades de estocagem (0,1, 0,4, 0,7 e 1,0 g/L), dois aquários (aquários de vidro e cerâmica) e quatro repetições. O experimento durou 60 dias utilizando 148 peixes juvenis (3,05 ± 0,09 g) distribuídos aleatoriamente em 32 aquários (50 L) equipados com filtros e aeração. Todos os peixes receberam duas refeições diárias ad libitum (8h e 16h). Parâmetros de qualidade da água como temperatura, oxigênio dissolvido, pH e amônia total foram medidos. Ao final do experimento, todos os peixes foram medidos e pesados para determinação do desempenho de crescimento e posteriormente submetidos à análise parasitológica. Os dados foram analisados por meio de ANOVA a dois fatores com teste post-hoc de Tukey (p<0,05). Não foram observados efeitos no desempenho do crescimento em diferentes densidades de estocagem. Entretanto, houve um aumento na infestação por Capillaria pterophylli na alta densidade de estocagem dentro dos aquários cerâmicos. Assim, este estudo recomenda o uso de 1,0 g/L para o sistema intensivo de aquicultura de acarás de água doce, e aplicação de manejo de limpeza para evitar a infestação parasitária, principalmente em aquários cerâmicos.
Among the potential feed additives, β-glucans are known to positively affect the growth performance, blood parameters, and intestinal microbiota of fish, even the ornamental species. Therefore, the ...present study evaluated the effects of the dietary supplementation of different Saccharomyces cerevisiae β-glucans concentrations (0, 0.05, 0.1, and 0.2%) in juvenile angelfish (Pterophyllum scalare) over a 42-day period. Regarding growth performance, no effects were observed on most parameters. However, 0.2% β-glucans supplementation produced higher condition factor values, indicating a better nutritional status. Furthermore, β-glucans supplementation did not affect blood parameters. Regarding intestinal microbiota, β-glucans supplementation increased the abundance of the potentially beneficial bacterial genus Phascolarctobacterium. The high abundance of bacteria from the phylum Bacteroidetes, which can degrade β-glucans, may be attributed to the increased abundance of Phascolarctobacterium spp. In addition, 0.2% β-glucans supplementation produced more operational taxonomic units and higher Sobs (observed species richness), indicating effects on the overall bacterial community structure. These results demonstrate the potential application of β-glucans as a dietary supplement to improve the performance and modulate the intestinal microbiota of angelfish.
Nontuberculous mycobacteria infection is one of the most common chronic bacterial diseases in ornamental aquarium fish and appears to be directly related to stressful husbandry practices. ...Furthermore, it also represents zoonotic potential. Here we present the isolation and characterization of non-tuberculous mycobacteria from diseased freshwater angelfish (Pterophyllum scalare) in São Paulo, Brazil. Nine discarded breeding females with signs of disease were evaluated. The fish exhibited lethargy, loss of appetite, cachexia, skin ulcers, and exophthalmia. At necropsy, four fishes presented macroscopic granulomas in the spleen. Mycobacterium chelonae, M. fortuitum, M. gordonae, M. intracellulare and M. peregrinum were isolated and identified by hsp65 PCR restriction analysis. Histopathological analysis revealed microscopic lesions compatible with mycobacteriosis, and Mycobacterium bacillus were observed by Ziehl-Neelsen stain. Notably, all Mycobacterium species identified in this study have already been reported in human patients; therefore, diseased animals may be a source of infection for people who handle fish and aquariums.
This study verified the effects of essential oils from
Lippia sidoides
(EOLS) and
Cymbopogon citratus
(EOCC) on the anesthesia of freshwater angelfish (
Pterophyllum scalare
) of two different sizes ...(juveniles I (0.82 g) and II (2.40 g)) and the transport (8 h) of juveniles II. Fish were exposed to different concentrations of EOLS and EOCC: 0, 10, 25, 50, 75, 100, 150, 200, and 250 mg L
−1
. Ventilatory rate (VR) and transport for 8 h with 0, 10, and 15 mg L
−1
of each essential oil were evaluated in juveniles II. The major components found in EOLS and EOCC were carvacrol (44.50%) and α-citral (73.56%), respectively. The best sedation and anesthesia times for both essential oils were obtained with 10 and 25 mg L
−1
and 200 and 250 mg L
−1
for juveniles I and II, respectively. Fish sedated with EOLS had lower VR values than the other treatments. Blood glucose levels were higher in ornamental fish transported with 10 and 15 mg EOLS L
−1
and 15 mg EOCC L
−1
. Hepatic glycogen values were higher in the control group. In general, fish transported with 10 mg EOLS L
−1
showed fewer gill histological alterations than other transported fish. When the type of lesion was evaluated, the highest gill alterations occurred in fish transported with EOCC. In conclusion, 10 mg EOLS L
−1
could be used to transport of juveniles II because although this concentration increased blood glucose levels, it decreased the VR and muscle glycogen levels and caused only mild alterations to the gills.
Pterophyllum scalare belongs in the family Cichlidae of Cichliformes. This species and its congeners are characterized by a compressed and disc-shaped body with dorsal and anal spiny rays increasing ...in length from anterior to posterior part of the fin. In this study, we determine and describe the complete mitogenome sequence of Pterophyllum scalare for the first time, which is 16,494 bp in length, and contains 37 genes, including 13 protein-coding genes, 2 rRNAs, 22 tRNAs, 1 origin of replication on the light-strand (O
L
) and a putative control region. The overall base composition is 27.5% A, 26.8% T, 30.1% C and 15.6% G, with a slight AT bias (54.3%). All protein-coding genes share the start codon ATG, except for COI that begins with GTG. These results are expected to provide useful molecular data for phylogenetic studies of Cichlidae and Cichliformes. Maximum Likelihood (ML) tree and Bayesian analyses based on partitioned nucleotide sequences of 12 mitochondrial protein-coding genes were constructed and both yielded trees with identical topologies.
Shoal choice studies have revealed that fish have cognitive abilities to discriminate between groups of different composition. In this work, the role of social status (based on aggressive acts) of ...both the test fish and the fish in the stimulus shoals was examined because of the fitness-related consequences that group association may have for the test individual. Single angelfish of high and low social status (dominant and subordinate) were presented with a choice between two stimulus shoals composed of three conspecifics of equal size and familiarity but of social status equal to, and different from that of the test fish in the same dominance hierarchy. Test fish, irrespective of the social status, spent significantly more time shoaling with subordinates that with dominants. They also initiated shoaling behaviour with subordinates more readily and the number of visits to the preference zone close to the subordinates was greater than that to dominants. The tendency was greater in subordinate fish, which showed longer latency in approaching the shoals of dominants, and spent more time in proximity to the subordinates per visit than did dominant fish. A replicate preference test indicated that this general pattern was relatively stable for at least 2 1/2 hr. A possible factor mediating this association preference, that of familiarity, was then tested. The same protocol as before was used but unfamiliar conspecific dominants and subordinates served as stimulus shoals. In this second experiment, generally test fish did not show any significant shoaling preference. The results indicate that angelfish are capable of distinguishing the social status of conspecifics and can discriminate between shoals composed of dominants and subordinates on the basis of previous interactions. It is suggested that the tendency to avoid shoals of dominant companions may be due to the disadvantage of enhanced competition, subordinates being more affected.
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