Development of digestive biochemistry in the initial stages of three cultured Atherinopsids

Abstract

The early development of the digestive biochemistry of three cultured Atherinopsids (two Odontesthes species and Chirostoma estor) was investigated. Relatively high lipolytic and high alkaline proteolytic activities were found in all species. In addition, gene expression of lipase and trypsin during the early development of C. estor not only indicates an early onset of the lipase activity but also demonstrates a major importance of protein digestion in this species. However, despite all of them share similar habitats, differences in their digestive activities were evident. The rise in the activities of brush border membrane enzymes correlated with the decrease in cytosolic activities, used as indicator of maturation of the digestive tract, was detected in both species of Odontesthes at 9 weeks after hatching. In contrast, no similar signs were measured in C. estor, this being in agreement to the long weaning period (nearly 5 months) reported for this species.

Regulation of somatic growth and gene expression of the GH–IGF system and PRP-PACAP by dietary lipid level in early juveniles of a teleost fish, the pejerrey (Odontesthes bonariensis)

“…The different results in terms of growth between our study and Chalde et al (2011), which was developed in the same experimental facilities than ours, might be provoked by many factors, including variations in the broodstock origin and the initial size of the fish at hatching, the water temperature (that in our study oscillated between 17 ± 1°C, whereas they kept constant at 17°C), the diet composition and the starting date of the artificial feeding (27 vs. 42 dah). The mentioned studies by Toledo-Cuevas et al (2011) and Chalde et al (2011) do not show the formulations of their experimental diets; therefore, it is possible to speculate that in our study the lack of additional sources of phospholipids to those provided by fishmeal (i.e., soy or marine lecithin) might have been a contributing factor responsible of the lower growth rates exhibited by our fish. In this sense, previous studies developed with marine fish larvae have addressed the convenience of including a small amount of phospholipids in the diets, in order to maximize growth and survival, among others (Cahu et al 2003;Villeneuve et al 2007).…”

“…One of the main limitations to promote rapid growth rates under rearing conditions arise from the lack of knowledge about the nutritional requirements of larvae and juveniles of pejerrey. So far, most of the practical research developed in this fish species has been focused on the improvement of the rearing techniques and the obtaining of high-quality eggs in indoor tanks but, to our knowledge, very few studies have been focused on the effects of dietary formulations alternative to live prey on the growth performance and nutrition physiology of both larvae and juveniles of this fish species (Piedras et al 2004;Hualde et al 2011;Toledo-Cuevas et al 2011).…”

Pituitary–thyroid axis development during the larval–juvenile transition in the pejerrey Odontesthes bonariensis

“…For instance, the transition of feeding stage from live food to artificial diet in this species can be done after reaching a body length of 20 mm (Strüssmann & Yasuda, ), which is generally attained between 5 and 6 wph. Moreover, the morphology and function of alimentary tract, as well as the ability to produce the digestive enzyme trypsin, is completely developed at this size (Toledo‐Cuevas et al, ). The increase in THs at stage E could also be related to gonadal differentiation during the transition from larva to juvenile and the acquisition of the final sex phenotype, since the first signs of ovarian differentiation in O. bonariensis reared under similar conditions have been observed between 4 and 7 wph (Ito et al, ).…”

A complete chitinolytic system in the atherinopsid pike silverside Chirostoma estor: gene expression and activities

“…Ad hoc balanced diets are essential for fish cultures and the development of an adequate diet has been supported by studies on the digestive biochemistry (Kolkovski, ; Cahu et al , ; Zambonino Infante & Cahu, ) of C . estor (Toledo‐Cuevas et al , ). Given that C .…”