Trypsin and chymotrypsin as indicators of nutritional status of post‐weaned sea bass larvae

Abstract

The aim of the present work was to evaluate to what extent variation in the activity of either trypsin or chymotrypsin could be a sensitive and reliable indicator of nutritional deficiencies during post-weaning stages in a marine fish. Sea bass Dicentrarchus labrax larvae obtained from two different spawns classified as high quality (HQ) or low quality (LQ) on the basis of their hatching variables, were used to evaluate if enzyme production could be conditioned by factors other than those related to the feeding regime. In addition, larvae in each group were either fed normally or received a ration reduced by 60%. Trypsin and chymotrypsin activities were separately measured in larvae at days 3 and 15 after weaning. Changes in mass and final survival were also recorded. Food limitation resulted in a lower final mass only in the HQ larvae. Survival was significantly higher in HQ larvae, but also in larvae suffering food restriction, irrespective of the quality of the spawn. In both groups of larvae, lower food availability was correlated to increased values of trypsin, and particularly, of chymotrypsin. Variations were high enough to support the usefulness of such enzymes as indicators of a modified nutritional status. It is suggested that the noticeable increase in the activity of both enzymes observed in the restrictedly fed larvae could compensate initial deficiencies and explain the good results in growth and survival obtained in LQ larvae.

Starving/re-feeding processes induce metabolic modifications in thick-lipped grey mullet (Chelon labrosus, Risso 1827)

“…However, other species showed a different effect after a brief starvation, with an increase in enzymatic activities in the digestive tract (Gildberg, 2004). It follows that the analysis of these activities may be an easy and reliable method that can be used as indicator of the nutritional condition in a given species of fish (Hidalgo et al, 1999;Sunde et al, 2004;Cara et al, 2007).…”

Assessment of enzymatic efficiency on protein digestion in the tilapia Oreochromis niloticus

“…In the last years, a great number of papers have been focused to the characterization of the type and amount of enzymes present in the digestive tract of fish (Chan et al 2004;Papoutsoglou and Lyndon 2005;Liu et al 2008), as well as to their response to changes in food composition (Applebaum and Holt 2003;Papoutsoglou and Lyndon 2006a;Cara et al 2007). Such works offer highly valuable information about species-specific differences existing between enzymes in their ability to hydrolyze specific substrates, this being to a great extent a key factor explaining the observed differences in the digestibility of the main nutrients in feeds.…”

Developmental and moult cycle related biochemical changes in larvae of the spider crab, <i>Maja brachydactyla</i> (Brachyura: Majidae)

“…The effects of early feeding conditions on aquatic organisms are generally assessed with a number of indicators commonly referred to as "physiological condition indices". A variety of morphometrical, histological and biochemical parameters are routinely applied to evaluate condition and feeding history in wild and cultured populations of larval fish (Gisbert et al 2004, Cara et al 2007, Shan et al 2009) and crustaceans (Rotllant et al 2001, Johnston et al 2004, Figueiredo et al 2008.…”