Skeletal Anomalies of Pacu, Piaractus mesopotamicus, Larvae from a Wild‐caught Broodstock

Abstract

Skeletal anomalies in fish are frequent, representing a major problem for the aquaculture industry. The anomalies usually arise in the larval phase and worsen, persist, or recover over the ensuing stages of development. In addition to impairing larval quality, they compromise the growth, health, and food conversion of fish, lowering their economic value. This study evaluated the occurrence of skeletal anomalies in pacu larvae during the first 30 d of development. The newly hatched larvae of six breeding pairs taken from the Paranapanema River (offspring A, B, C, D, E, and F) and subjected to induced spawning were reared separately for 30 d, feeding on live prey (Artemia nauplii). Nearly 20 larvae from each breeding pair were killed and stored 1, 2, 4, 6, 8, 10, 13, 16, 19, 22, 25, and 30 days post‐hatching. The larvae were stained to differentiate cartilage and bones and examined under a stereo microscope. A total of 1310 larvae were checked for the presence (1) or absence (0) of anomalies in the head, vertebral column, and fins. Associations between growth parameters (total length [TL] vs. standard length [SL]; SL vs. vertebral column length [VL]) were obtained by regression. Correspondence analysis was used to correlate data on the different parameters evaluated. On completion of observation, larvae from pair E had the highest SL, whereas offspring F were the shortest. All types of skeletal anomalies were detected in the larvae irrespective of the offspring, affecting the normal growth of pacu larvae obtained from wild‐caught breeders.

Predicted 2100 climate scenarios affects growth and skeletal development of tambaqui (Colossoma macropomum) larvae

“…The aforementioned anomalies were also found in larvae deriving from wild broodstocks, as verified by Lopes et al. () in pacu Piaractus mesopotamicus , a phylogenetically closely related species of tambaqui. In this case, the appearance of anomalies is unpredictable, as several factors are involved in fish ontogeny.…”

“…Tambaqui larvae will not develop its skeleton in a normal way when facing climate change expected for the end of the century, especially under moderate and extreme conditions of high temperatures, dissolved CO 2 and water acidity, as observed in the A1B and A2 scenarios (IPCC, ). These climatic conditions resulted in severely structurally compromised skeletons, with marked notochord curvatures (lordosis, scoliosis and kyphosis), certainly affecting the animal's welfare and its fitness both in natural and artificial environments (Boglione et al., , ; Izquierdo et al., ; Lopes, Freitas, Jomori, Carneiro, & Portella, ). Poorly developed structures in the craniofacial skeleton were also observed (e.g., crooked upper and lower jaws), which may hinder larvae growth by directly affecting food capture (Boglione et al., ), as verified in the A2 scenario.…”

“…It is noteworthy that almost 40% of the larvae exposed to the A2 scenario showed at least one type of bone malformation, while in the remaining controlled rooms, the occurrence of anomalies was significantly lower. In pacu larvae obtained from wild broodstock and reared in captivity, the incidence of cranial and column anomalies were 10.9% and 15.8%, respectively (Lopes et al., ).…”

“…a better larval quality index was observed for the larvae exposed to the current conditions ( Figure 3). (Boglione et al, 2009Izquierdo et al, 2010;Lopes, Freitas, Jomori, Carneiro, & Portella, 2014). Poorly developed structures in the craniofacial skeleton were also observed (e.g., crooked upper and lower jaws), which may hinder larvae growth by directly affecting food capture (Boglione et al, 2009), as verified in the A2 scenario.…”

Growth, survival and bone alterations in <italic>Piaractus mesopotamicus</italic> larvae under different rearing protocols

“…This is in agreement with the results of LOPES et al (2014) who reported absence of skeletal abnormalities on the vertebral axis in pacu larvae after 30 days of rearing under laboratory conditions. In contrast, the incidence of skeletal abnormalities observed on vertebral centrum in L S could be associated to a possible deficiency or imbalance of some nutrients in the feeding of specimens that have high growing potential under these systems.…”