Effect of dietary carbohydrate sources on growth performance and utilization for gibel carp (Carassius auratus gibelio) and Chinese longsnout catfish (Leiocassis longirostris Gunther)

Abstract

The nutritional function of monosaccharides, disaccharides and polysaccharides for omnivorous gibel carp and carnivorous Chinese longsnout catfish were investigated and the ability of these two species to utilize carbohydrates was compared. For each species, triplicate groups of fish were assigned to each of five groups of isoenergetic and isonitrogenous experimental diets with different carbohydrate sources: glucose, sucrose, dextrin, soluble starch (acidmodified starch) and a-cellulose. The carbohydrates were included at 60 g kg )1 in Chinese longsnout catfish diets and at 200 g kg )1 in gibel carp diets. A growth trial was carried out in a recirculation system at 27.8 ± 1.9°C for 8 weeks.The results showed that fish with different food habits showed difference in the utilization of carbohydrate sources. For gibel carp, better specific growth rate (SGR) and feed efficiency (FE) were observed in fish fed diets containing soluble starch and cellulose, but for Chinese longsnout catfish, better SGR and FE were observed in fish fed diets containing dextrin and sucrose. Apparent digestibility coefficient of dry matter (ADC d ) and apparent digestibility coefficient of energy (ADC e ) were significantly affected by dietary carbohydrate sources in gibel carp. ADC d and ADC e significantly decreased as dietary carbohydrate complexity increased in Chinese longsnout catfish except that glucose diet had medium ADC d and ADC e . In both species, no significant difference of apparent digestibility coefficient of protein was observed between different carbohydrate sources. Dietary carbohydrate sources significantly affected body composition, and liver phosphoenolpyruvate carboxykinase (PEPCK), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PD) and malic enzyme (ME) activities also varied according to dietary carbohydrate complexity. Fish with different food habits showed different abilities to synthesize liver glycogen, and the liver glycogen content in gibel carp was significantly higher than in Chinese longsnout catfish. The influence of carbohydrate source on gluconeogenesis and lipogenesis was also different in the two fish species.KEY WORDS

Nutritional regulation of hepatic glucose metabolism in fish

“…Thus, in gibel carp plasma glucose levels were higher in fish fed dextrin compared to fish fed glucose or starch, whereas in Chinese longsnout catfish plasma glucose levels were higher in fish fed the glucose diet than in fish fed the dextrin or starch diets. The significant correlation observed between plasma glucose levels and liver PEPCK activities in both species (r = 0.6355 in gibel carp and r = 0.6073 in Chinese longsnout catfish) supports this hypothesis (Tan et al 2006).…”

“…Thus, in European sea bass, a higher induction of liver PK activity by glucose than by starch was observed (Enes et al 2006b), whereas in gibel carp Carassius auratus and Chinese longsnout catfish Leiocassis longirostris, PK activity was significantly higher in fish fed diets containing sucrose than glucose, dextrin or starch (Tan et al 2006). In common carp, comparatively to fish fed a high protein diet without carbohydrates, dietary supplementation with 30% of starch, glucose, or fructose had no effect on hepatic PK activity, whereas supplementation with 30% of galactose depressed PK activity (Shikata et al 1994).…”

“…The effect of dietary carbohydrate complexity on PEPCK activity was studied in the liver of gibel carp and Chinese longsnout catfish (Tan et al 2006). While in gibel carp higher PEPCK activities were observed in fish fed dextrin than glucose and starch, in Chinese longsnout catfish, PEPCK activity was higher in fish fed glucose and sucrose than dextrin or starch.…”

Effect of Dietary Lipid Sources on Body Fatty Acid Composition of Chinese Longsnout Catfish Leiocassis longirostris

“…In recent years, cultures of this fish species have been expanding due to an increasing demand from consumers. Some studies on protein, lipid and carbohydrate requirements of this species have been conducted (Lim et al, 2013;Tan et al, 2006Tan et al, , 2007Pei et al, 2004Pei et al, , 2005. In considering studies on optimum levels of lipid, 7-14% seems to be enough for energy need of this species, but limited information is available on using different lipid source in diet.…”

Transcriptomic and Metabolomics Analyses Show that High Carbohydrate Induces Fatty Liver in Blunt Snout Bream (<em>Megalobrama amblycephala</em>)<strong></strong>

“…Compared with mammals, the utilization of carbohydrate in fish is limited and can be affected by the level and source of the dietary carbohydrate. For example, reduced growth performance and feed utilization were observed in several fish species fed a glucose diet compared with those of fish fed a starch diet [11,12]. Overingestion of simple carbohydrates, such as sucrose and fructose is a major cause of nonalcoholic fatty liver disease (NAFLD) [13].…”