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Post Hatching (post + hatching)
Selected AbstractsEarly development of the digestive tract (pharynx and gut) in the embryos and pre-larvae of the European sea bass Dicentrarchus labraxJOURNAL OF FISH BIOLOGY, Issue 6 2009E. Sucré The European sea bass Dicentrarchus labrax is a marine teleost important in Mediterranean aquaculture. The development of the entire digestive tract of D. labrax, including the pharynx, was investigated from early embryonic development to day 5 post hatching (dph), when the mouth opens. The digestive tract is initialized at stage 12 somites independently from two distinct infoldings of the endodermal sheet. In the pharyngeal region, the anterior infolding forms the pharynx and the first gill slits at stage 25 somites. The other three gill arches and slits are formed between 1 and 5 dph. Posteriorly, in the gut tube region, a posterior infolding forms the foregut, midgut and hindgut. The anus opens before hatching, at stage 28 somites. Associated organs (liver, pancreas and gall bladder) are all discernable from 3 dph. Some aspects of the development of the two independent initial infoldings seem original compared with data in the literature. These results are discussed and compared with embryonic and post-embryonic development patterns in other teleosts. [source] Assessment of digestive enzymes activity during the fry development of the endangered Caspian brown trout Salmo caspiusJOURNAL OF FISH BIOLOGY, Issue 4 2009A. Zamani The study of digestive enzymes activity at Salmo caspius fry showed that enzymes were available at the moment of mouth opening on the first day post hatching (dph) and the activity of enzymes showed no significant difference from the hatching day 28 dph. An increased activity was seen between 32 and 43 dph and this activity was significantly higher than the activity during the first 28 days. In the primary stages after yolk sac resorption (43,58 dph), enzymes activity showed an increased profile, however none of them showed a significant difference between 43 and 58 dph. [source] Effects on growth and survival of loach (Misgurnus anguillicaudatus) larvae when co-fed on live and microparticle dietsAQUACULTURE RESEARCH, Issue 4 2009Youji Wang Abstract The effectiveness of co-feeding loach (Misgurnus anguillicaudatus) larvae with live and microparticle diets on weaning performance was described here. Dry weight, total length, length and weight-specific growth rate (SGR) and survivals were monitored at 23,25 °C from the 4th day post hatching (dph) in different diet regimes, which included: microparticle diets (A), live cladocerans (B), enriched cladocerans (C), half microparticle diets plus half live cladocerans (D) and half microparticle diets plus half enriched cladocerans (E). The SGR (L and W) were significantly lower in treatment A than in other treatments after completing metamorphosis (day 4,20, P<0.05). On 30 dph, dry weight (mg) and total length (mm) were significantly lower in treatment A than in other treatments (P<0.05). There were no significant differences in growth in treatments B, C, D and E before 30 dph. However, when live feed was withdrawn from 31,60 dph, in metamorphosed fish, there were significant differences (P<0.05) among the treatments in survival and growth. Metamorphosed fish in treatment E had higher survival than the fish in other treatments at the end of the experiment. The SGR (L and W) of weaned fish in treatments B and C were similar but lower than in treatments A, D and E respectively. However, dry weight and total length in treatment A were significantly lower than in treatments D and E. It is suggested that weaning of M. anguillicaudatus from early development would appear to be feasible and that larval co-feeding improves the growth and the survival. [source] Morphological development of post hatch larval goldlined seabream Rhabdosargus sarba (Forskål, 1775)AQUACULTURE RESEARCH, Issue 12 2006Fahad S Ibrahim Abstract Ultrastructural changes in Rhabdosargus sarba larva in early life history were investigated. At hatching, the digestive system was histologically undifferentiated. The digestive tract was a straight tube attached to the dorsal end of the yolk-sac and was not connected to either the mouth or the anus. The layer of gut epithelium at some regions of the luminal surface was straight and microvilli were not present. These straight borders were not observed at 1 day post hatching (DPH) onwards as microvilli increased in number on the luminal surface and became more regular. At 2 DPH, the digestive system was well differentiated and the separation of the mid- and hindgut by the intestino-rectal valve became more advanced. At 0 DPH, the eye was spherical and the retina had a zonation with undifferentiated cells. The eye also lacked differentiated photoreceptors (PR). The retinal PRs increased in length and in number as the yolk-sac was absorbed. By 2 DPH, the eye was fully pigmented, suggesting that the larval vision system was functional. The larvae had a pure cone retina at the onset of exogenous feeding. Morphological and functional differentiation of the digestive tract and the eye of the larvae preceded the completion of yolk and oil globule absorption. The oil globule was exhausted at 4 DPH and at 2 DPH, the yolk-sac was completely absorbed. Food particles were observed at 3 DPH. Food particle ingestion and absorption of the yolk-sac were observed as vision became fully functional. [source] | ||||||||||