The changes in digestive enzymes and hormones of gilthead seabream larvae (Sparus aurata, L 1758) fed on Artemia nauplii enriched with free methionine

Abstract

Variations in digestive enzymes and hormones during the larval development of gilthead seabream (Sparus aurata) fed on live prey (Artemia nauplii) enriched with free methionine were investigated for 16 days (from day 24 to day 40). Prior to initiation of the experiment, newly hatched larvae were transferred from incubators to fiber glass tanks (300 l) with black walls and fed with same diets until day 24. Each experiment was performed in triplicate. In the experimental group, the content of the free methionine in the Artemia nauplii was increased by adding a 5.3 mM free methionine solution to the culture water during a 16-h enrichment period. The larvae of both the control and enrichedmethionine groups were sampled four times, with 4-day intervals between samplings, during a 16-day period. The larvae in the control group had a significantly lower growth than those of the methionine group at the end of the study (P \ 0.05). The highest trypsin activity and leucine aminopeptidase N/leucine-alanine peptidase ratios were observed in the control group. A significant difference between bombesin activities in the treatment groups was not found at 5th minute after the initiation of feeding (P [ 0.05), but they were significant at 15th minute post-initiation of feeding (P \ 0.05). A significant difference between the cholecystokinin levels of the treatment groups was found (P \ 0.05).

The effects of methionine‐enriched Artemia nauplii on growth, amino acid profiles, absorption enzyme activity and antioxidant capability of common carp ( Cyprinus carpio var. Jian) larvae

“…Artemia nauplius obtains enough methionine from marine water rich in methionine mainly through non‐selective filter feeding (Tonheim, Koven, & Rnnestad, ). The methionine will accumulate in the intestinal tract, where it can be absorbed into the tissue and body fluids to increase the level of methionine (Naz & Tu¨rkmen, ; Tonheim et al, ). For fish living in freshwater, the availability of methionine is severely limited without artificial supplementation in the diet (Nwanna, Lemme, Metwally, & Schwarz, ).…”

“…As one of the main limiting amino acids for fish living in freshwater, methionine plays a vital role in the transition from larval to juvenile fish. Research has shown the effect of methionine on food consumption, thereby increasing the growth of larvae (Mamauag et al, ; Naz, et al, ; Nordrum, Krogdah, Røsjø, Olli, & Holm, ). During the first period of this experiment (1–7 days), the addition of more than 400 mg/L methionine led to significant increases in SGR and BLGR values.…”

“…At first feeding, the digestive function of larvae is relatively weak and the activities of enzymes for digestion and absorption are low (Naz, et al, ; Rønnestad et al, ). During the experiment period, the activities of γ‐GT and Na+/K+‐ATPase in carp larvae feeding on Artemia nauplii enriched with different levels of methionine increased as the level of supplemental methionine increased.…”

“…Methionine acts via various mechanisms, such as the regulation of fish growth, the improvement of digestion and absorption capacity, the increase in the protein utilization ratio, and sulphur metabolism (Alam, Teshima, Ishikawa, & Koshio, ; Espe, Hevrøy, Liaset, Lemme, & El‐Mowafi, ; Sveier, Nordas, Berge, & Lied, ). Mamauag et al () showed that the growth performance of Pagrus major larvae could be improved with the addition of methionine and Naz and Türkmen () demonstrated that methionine could increase the digestive enzyme activity and hormone levels of gilthead seabream larvae ( Sparus aurata , L 1758). However, the studies only focused on the effect of methionine on the physiological function of larval and juvenile fish living in marine habitats.…”

Different tolerances of jellyfish ephyrae (Aurelia sp. 1) and fish larvae (Paralichthys olivaceus) to nutrient limitations

“…A reduction in amino acid contents affects fish larvae, especially at the start of exogenous feeding (Rønnestad et al 1999, Park et al 2000, Wright & Fyhn 2001, Alam et al 2002, Kim et al 2003, Aragão et al 2004). In the early stages, the larval digestive system is not fully developed, and complex proteins are not easily digested (Rønnestad et al 1999, Aragão et al 2004, Naz & Türkmen 2009. Because the free amino acid (FAA) content could be absorbed by fish larvae rapidly and efficiently (Alam et al 2001, Applebaum & Rønnestad 2004, Ohkubo et al 2008, the FAAs were essential for fish larvae.…”