Carbohydrate utilization by herbivorous and omnivorous freshwater fish species: a comparative study on gibel carp (Carassius auratus gibelio. var CAS III) and grass carp (Ctenopharyngodon idellus)

Abstract

Two 8-week feeding trials were conducted to evaluate dietary carbohydrate utilization by omnivorous gibel carp (Carassius auratus gibelio) (2.4 AE 0.1 g) and herbivorous grass carp (Ctenopharyngodon idellus) (6.5 AE 0.1 g). Five isonitrogenous (370 g kg À1 ) and isolipid (70 g kg À1) diets were formulated with increasing corn starch levels (60, 140, 220, 300 and 380 g kg À1 ). Resultsshowed that specific growth rate (SGR), feed efficiency (FE) and protein retention efficiency (PRE) of gibel carp significantly increased from dietary starch of 60 to 300 g kg À1 and then decreased from 300 to 380 g kg À1 , but those of grass carp showed no significant differences between treatments. Independent of dietary starch levels, grass carp gained significantly higher FE and PRE than gibel carp. Feeding rate (FR) of gibel carp was significantly higher than that of grass carp. In two fish species, high dietary starch (300 and 380 g kg À1 ) tended to obtain higher hepatosomatic index (HSI), serum triglyceride, hepatic lipid and body lipid contents. Serum glucose concentration of grass carp was not affected, while that of gibel carp fed the starch of 300 g kg À1 diet was significantly lower than those of the fish fed other four diets (60, 140, 220 and 380 g kg À1). Grass carp showed high tolerance to dietary starch while dietary corn starch should be no more than 300 g kg À1 for gibel carp. High starch contents may cause lipid accumulation in the liver and body.

Regulations on glucose metabolism affected by dietary carbohydrate in different strains of juvenile gibel carp (Carassius gibelio)

“…The present study found that the inclusion of digestible carbohydrate increased feeding rate (30C and 45C diet), but failed to improve fish growth. It is different with previous report that higher SGR of gibel carp was found in 30% corn starch diet when carbohydrate supplement from 6% to 38% (Li et al, 2016); this may associate with formulation of diets, especially for the fish meal content, and also with the difference in fish size. High carbohydrate diet showed presently protein-sparing effect of digestible carbohydrates by higher FE and PRE of 45C diet in accordance with previous reports (Kaushik, Medale, Fauconneau, & Blanc, 1989;Kim & Kaushik, 1992;Wilson, 1994).…”

Effects of dietary carbohydrate level on growth, biochemical composition and glucose metabolism of juvenile sea cucumber Apostichopus japonicus (Selenka)

“…Digestive enzyme activities were determined by a series of factors, such as food, gene and nutritional habits (Zhang et al, 2010). Amylase activity could be induced by appropriate dietary carbohydrate level (Li et al, 2014); however, it was not found further increased but decreased when dietary carbohydrate level was higher than 45.31%, which indicated that excess carbohydrate level could inhibit amylase activity. Moreover, some researchers thought that there was no relationship between amylase activity and dietary carbohydrate level, and it was determined by genome and development (Drewe et al, 2004;German et al, 2004).…”

Molecular adaptations of glucose and lipid metabolism to different levels of dietary carbohydrates in juvenile Japanese flounderParalichthys olivaceus

“…Fish, especially carnivorous fish, tend to be poor users of dietary carbohydrates (NRC, ). Diets for herbivorous and omnivorous fish species can be formulated containing 300–500 g/kg of carbohydrates (Boonanuntanasarn, Jangprai, et al, ; Li et al, ; NRC, ). However, for carnivorous species such as yellowtail kingfish ( Seriola lalandi ), largemouth bass ( Micropterus salmoides ) and Chinese longsnout catfish ( Leiocassis longirostris ), the amount of carbohydrates included in diets is generally <200 g/kg (Booth, Moses, & Allan, ; Liu et al, ; Tan, Xie, Zhu, Lei, & Yang, ).…”