Dietary TAG source and level affect performance and lipase expression in larval sea bass (Dicentrarchus labrax)

Abstract

The influence of dietary TAG source (fish oil, triolein, and coconut oil) and level (7.5 and 15% of the diet) on growth, lipase activity, and mRNA level was studied in sea bass larvae, from mouth opening until day 24 and from day 37 to 52. Fish oil and triolein induced better growth in both experiments, this being significant at a higher dietary level. Coconut oil significantly decreased growth at the higher level, possibly as the result of an excessive supply of medium-chain TAG. Growth was not related to lipase specific activity, suggesting a production in excess to dietary needs. Body lipid content was positively related to dietary lipid level and was affected by lipid quality. In addition, larval FA composition generally reflected that of the diet. The source of dietary lipid, but not the quantity, was shown to affect lipase activity significantly. Coconut oil diets induced the highest lipase activity, whereas the effect of fish oil was age dependent-it was similar to coconut oil at day 24 but induced the lowest lipase activity in 52-d-old larvae. The differential lipase response was probably caused by differences in the FA composition of the diet, related to the specificity of lipase toward FA differing in chain length and degree of saturation. No significant differences were found in lipase/glyceraldehyde-3-phosphate dehydrogenase mRNA, which suggests the existence of a posttranscriptional regulation mechanism.

Ontogenetic development of digestive enzymes and effect of starvation in miiuy croaker Miichthys miiuy larvae

“…For example, we observed that lipase activity increased gradually throughout the yolk-sac period and peaked at the onset of exogenous feeding on 4 dah; it then decreased until 11 dah but increased again from 20 to 25 dah. This developmental pattern is similar to that observed in yellowtail kingfish (Chen et al 2006a) and sea bass (Zambonino Infante and Cahu 1994; Morais et al 2004) larvae but differs from that of California halibut and Cuban gar, which was found to show a continuous increase in lipase activity until a specific point is reached and the maintenance of a stable level thereafter (Alvarez-González et al 2006;Comabella et al 2006). Our observed increase in lipase activity during the yolk-sac period and peaking at the onset of exogenous feeding suggests that miiuy croaker larvae were ready to digest food prior to mouth opening.…”

Developmental changes in digestive enzyme activity in American shad, Alosa sapidissima, during early ontogeny

“…In addition, lipase activity then declined slightly from 14 to 27 DAH, which was followed by a rapid increase that coincided with the alteration of feeding regimes (cladocerans at 12 DAH and microdiet at 30 DAH). Lipase activity is strongly influenced by food type, lipid content, and composition of fatty acids in the diet, rather than lipolytic digestive capability (Morais et al 2004;Rønnestad et al 2013;Martínez-Lagos et al 2014). Moreover, Øie et al (2011) reported that a decrease in specific lipase activity was correlated with the lower lipid content of cladocerans.…”

Dietary neutral lipid level and source in Senegalese sole (Solea senegalensis) larvae: Effect on growth, lipid metabolism and digestive capacity

“…At 34 DAH the LS treatment was responsible for a significantly lower lipase segmental activity than the LF Artemia (one-way ANOVA). In a previous study performed with seabass larvae, the dietary lipid level was not found to affect lipase activity but the source of dietary lipid had a significant affect (Morais et al, 2004a). The differential lipase response was explained as being possibly caused by differences in the FA composition of the diet, related to the specificity of lipase towards FA differing in chain length and degree of saturation.…”

“…In terms of specific activity (i.e., after standardizing for larval size using protein content), no significant differences were found, even if there was a trend for a lower specific activity in larvae fed the HFArtemia. A reduction in lipase specific activity caused by formulated diets containing fish oil has been noted in 52 DAH seabass by Morais et al (2004a), where it was suggested that the higher digestibility of the diets containing PUFA and HUFA could eventually cause an adaptative response leading to lower lipase secretion. Regarding the alkaline phosphatase activity, a trend for higher activity was noted when larvae were fed lower lipid diets (particularly LF), and this "lipid level" effect was significant when a two-way ANOVAwas performed, both in terms of segmental and specific activity.…”

“…Trypsin activity was assayed using BAPNA (Na-benzoyl-DL-argininep-nitroanilide) (Sigma-Aldrich) as substrate (Tseng et al, 1982), while the activity of alkaline phosphatase was measured following the method of Bessey et al (1946), using as subtrate p-nitrophenylphosphate (pNPP) (Sigma-Aldrich). Lipase activity was assayed according to a spectrophotometric method slightly modified from Iijima et al (1998), using as substrate pnitrophenyl myristate (Sigma-Aldrich) (Morais et al, 2004a). Enzyme specific activities were expressed as μmoles of substrate hydrolyzed per minute, per mg of protein (i.e., U mg protein − 1 ) at 25°C for trypsin, 37°C for alkaline phosphatase and 30°C for lipase.…”