Effects of ursodeoxycholic acid on growth and digestive enzyme activities of Japanese flounderParalichthys olivaceus(Temminck & Schlegel)

Abstract

Three experiments were conducted to elucidate the effects of ursodeoxycholic acid (UDCA) on growth performance and digestive enzyme activities of Japanese¯ounder Paralichthys olivaceus (Temminck & Schlegel) juveniles and larvae. In experiment 1 (growth study), duplicate groups of juveniles of about 7 g initial body weight were fed a UDCA diet (containing 0.025% UDCA) and a control diet (without UDCA) to apparent satiation twice a day for 6 weeks at 18±21°C. In experiment 2 (enzyme study), triplicate groups of juveniles (7 g) were also fed the UDCA and control diets for 6 weeks under similar feeding and water management conditions to those for the growth study, digestive organs were collected every 2 weeks and their enzyme (aamylase, lipase and protease) activities were assayed. In experiment 3, duplicate groups of 48day-old larvae were fed two test microdiets (UDCA and control diets) for 30 min and assayed for enzyme activities 6, 12, 24, 36 and 48 h after a single feeding in the morning. The weight gain and feed conversion ef®ciency of the juveniles fed the UDCA diet in the growth study did not show any signi®cant difference compared to juveniles fed the control diet. Total lipids, neutral lipids and triglycerides of the whole body and apparent body retention (%) of dietary lipids were notably higher (P < 0.05) in the UDCA group than the control. In the juveniles fed the UDCA diet, the activities of a-amylase and protease did not increase with holding time compared to the control diet. Lipase activity of the juveniles fed the UDCA diet was signi®cantly higher than those fed the control diet. By contrast, the activities of a-amylase, lipase and protease of the larvae at 6, 12, 24, 36 and 48 h after ®nal feeding did not show any difference between the dietary groups. These results suggest that UDCA may have an important role in lipid assimilation by increasing enzyme activity of the juvenile Japanese¯ounder, but there are few effects on growth performance of the juveniles and digestive enzyme activities of the larvae.

Effect of dietary bile acids on growth, body composition, lipid metabolism and microbiota in grass carp (Ctenopharyngodon idella)

“…These results were consistent with previous studies that showed that BA improved growth performance in S. quinqueradiata (Deshimaru et al., ), A. japonica (Maita et al., ) and P. olivaceus (Alam et al., ). In this context, data from nutritional studies conducted in A. japonica (Maita et al., ), P. olivaceus (Alam et al., ) and S. prenanti (Zheng et al., ) indicated that BA might enhance lipase activity; thus, improving lipid digestion as it has been reported in in vivo and in vitro studies in higher vertebrates (Knarreborg, Jensen, & Engberg, ). In addition, BA might improve the emulsification of lipidic compounds, as well solubilizing them and enhancing lipid transport and absorption (Mukhopadhyay & Maitra, ; Romański, ).…”

“…Bile acids (BA), which are defined as amphipathic sterol compounds (Kortner, Gu, Krogdahl, & Bakke, ; Romański, ), have important roles in digestion and absorption of dietary lipids in the intestine (Hofmann & Hagey, ; Li, Jadhav, & Zhang, ) by contributing to the emulsification of fats in the chime and increasing the activity of bile salt‐activated lipase, as it has been described in Japanese flounder ( Paralichthys olivaceus ; Alam, Teshima, Ishikawa, & Koshio, ), Japanese eel ( Anguilla japonica ; Maita, Tachiki, Kaibara, Itawaki, & Ikeda, ) and in humans (Bauer, Jakob, & Mosenthin, ; Romański, ). In addition, dietary BA have been reported to improve growth performance in yellowtail ( Seriola quinqueradiata ; Deshimaru, Kuroki, & Yone, ), A. japonica (Maita et al., ), P. olivaceus (Alam et al., ), Prussian carp ( Carassius auratus gibelio ; Tan, Wei, & Zen, ) and cobia ( Rachycentron canadum ; Zhou et al., ). Bile acids have been reported to decrease lipid deposition in the liver of turbot ( Scophthalmus maximus ; Sun et al., ), giant prawn ( Macrobrachium rosenbergii ; Ma et al., ) as well as in higher vertebrates like rats (Pieters, Schouten, & Bakkerren, ), whereas they have also been reported to decrease body lipid deposition in R. canadum (Zhou et al., ) and in the cyprinid Schizothorax prenanti (Zheng et al., ).…”

Optimization of a gastrointestinal model applicable to the evaluation of bioaccessibility in fish feeds

“…Although some authors have not found a significant effect of including bile salts in the diet of fish on the activity of their digestive enzymes,32 a positive effect of conjugated bile acids on the rate of protein hydrolysis by human trypsin and chymotrypsin has been demonstrated in vitro 33. In that experiment, conjugated bile acids dramatically enhanced the proteolysis of several dietary proteins such as beta‐lactoglobulin, bovine serum albumin, myoglobin, and a commercially available dietary protein supplement.…”

Partial characterization of pyloric-duodenal lipase of gilthead seabream (Sparus aurata)

“…Although bile salts are recognized as factors affecting the functionality of fish lipases (Iijima et al 1998), very few papers have studied the composition or their role in the digestion of cultured fish. From such studies, it is deduced that teleosts have principally taurocholate and taurochenodeoxycholate (the taurine derivative) in their bile salts (Une et al 1991;Alam et al 2001). In fact, classification of fish lipases recognized such a strong dependence by identifying some activities reported in different species as ''bile salt-dependent lipases'' (BSDL).…”