Changes in digestive enzyme activities during larval development of leopard grouper (Mycteroperca rosacea)

Abstract

The leopard grouper is an endemic species of the Mexican Pacific with an important commercial fishery and good aquaculture potential. In order to assess the digestive capacity of this species during the larval period and aid in the formulation of adequate weaning diets, this study aimed to characterize the ontogeny of digestive enzymes during development of the digestive system. Digestive enzymes trypsin, chymotrypsin, acid protease, leucine-alanine peptidase, alkaline phosphatase, aminopeptidase N, lipase, amylase and maltase were quantified in larvae fed live prey and weaned onto a formulated microdiet at 31 days after hatching (DAH) and compared with fasting larvae. Enzyme activity for trypsin, lipase and amylase were detected before the opening of the mouth and the onset of exogenous feeding, indicating a precocious development of the digestive system that has been described in many fish species. The intracellular enzyme activity of leucine-alanine peptidase was high during the first days of development, with a tendency to decrease as larvae developed, reaching undetectable levels at the end of the experimental period. In contrast, activities of enzymes located in the intestinal brush border (i.e., aminopeptidase and alkaline phosphatase) were low at the start of exogenous feeding but progressively increased with larval development, indicating the gradual maturation of the digestive system. Based on our results, we conclude that leopard grouper larvae possess a functional digestive system at hatching and before the onset of exogenous feeding. The significant increase in the activity of trypsin, lipase, amylase and acid protease between 30 and 40 DAH suggests that larvae of this species can be successfully weaned onto microdiets during this period.

Changes in digestive enzyme activities during larval development of Chinese loach Paramisgurnus dabryanus (Dabry de Thiersant, 1872)

“…In the present study, the alkaline phosphatase specific activity of Chinese loach showed abrupt increase between 10 and 20 DAH, indicating the rapid development and/or formation of brush border enterocyte (Moyano et al 1996;Ribeiro et al 1999;Kvåle et al 2007) and an important development of the intestinal mucosa in terms of villi size and number (Pradhan et al 2013). Our results are in agreement with many other studies on the digestive physiology of fish larvae that reported an increase in intestinal brush border enzymes around the first weeks of their life stage (Babaei et al 2011;López-Ramírez et al 2011;Uscanga-Martínez et al 2011), indicating the onset of juvenile-like digestive mode (Ribeiro et al 1999;Martínez-Lagos et al 2014). The decrease in alkaline phosphatase specific activity was observed after 20 DAH as observed in yellowtail kingfish (Seriola lalandi) (Chen et al 2006), Mayan cichlid (López-Ramírez et al 2011) and butter catfish (Pradhan et al 2013).…”

“…Both amylase and lipase specific activities were detected as early as 1 DAH, suggesting that these enzymes were also genetically pre-programmed as reported in some other fish species (Cuvier-Péres and Lazo et al 2007;Martínez-Lagos et al 2014;Ma et al 2014). The amylase specific activity around 5 DAH was low coincided with the initial feeding, suggesting the poor ability of Chinese loach to utilize carbohydrates at mouth opening (4 DAH).…”

“…The sharp increase in pancreatic enzymes total activity of observed 10 DAH coincides with the initial supply of Cladocera. Several studies have found changes in enzyme activities in response to the quantity and quality of food, because this has been shown to stimulate digestive enzyme secretion in organisms (Cara et al 2007;Martínez-Lagos et al 2014). In addition, the increase in trypsin activity may be related to the formation of exocrine pancreas (Gisbert et al 2004;Tong et al 2012) from a morphohistological point of view.…”

“…Over the past decades, many new larval culture protocols have been developed with the aid of studies aiming to increase our knowledge with respect to larval digestive physiology (i.e., digestive enzyme activities and larval nutrition) of a species of interest, for example, for the Mayan cichlid (Cichlasoma urophthalmus) (López-Ramírez et al 2011), the butter catfish (Ompok bimaculatus) (Pradhan et al 2013), the common carp (Cyprinus carpio) (Farhoudi et al 2013), the meager (Argyrosomus regius) (Suzer et al 2013), the leopard grouper (Mycteroperca rosacea) (Martínez-Lagos et al 2014) and the three-spot cichlid (Cichlasoma trimaculatum) (Toledo-Solís et al 2015). These studies reflect the development of the digestive tract and digestive capability of the organism and can thus be used as an indicator of nutritional status at early life stage (Yúfera and Darías 2007) and can provide information for improving the feeding protocols of larviculture and offering a more suitable food item.…”

Reproductive cycle of leopard grouper Mycteroperca rosacea (Streets, 1877) held in captivity: relation ship between gonad development and sex steroid concentration

“…Wild mature individuals were induced to spawn with HCG producing >40,000 eggs/female (Gracia-López et al, 2004a) and hormonal induction on captive fish with HCG and LHRHa was successful producing over 2×10 6 eggs and fertilization rate of 62% (Kiewek-Martínez, 2004;. Embryonic development and egg and larval morphology and larval enzyme activity until the first feeding were described (GraciaLópez et al, 2004a;Martínez-Lagos & Gracia-López, 2009;Martínez-Lagos et al, 2014) and the effects of temperature and salinity on eggs and larvae also were studied (Gracia-López et al, 2004b). More than 1.7×10 6 eggs and 1.2×10 6 newly hatched larvae were achieved with a survival rate of 2.66% (Gracia-López et al, 2005).…”