Modulation of key metabolic enzyme of Labeo rohita (Hamilton) juvenile: Effect of dietary starch type, protein level and exogenous α-amylase in the diet

Department of Fish Nutrition and Biochemistry, Central Institute of Fisheries Education, Versova, Mumbai 400061, India.
Fish Physiology and Biochemistry (Impact Factor: 1.62). 06/2009; 35(2):301-15. DOI: 10.1007/s10695-008-9213-6
Source: PubMed


A 60-day feeding trial was conducted to delineate the effect of both gelatinized (G) and non-gelatinized (NG) corn with or without supplementation of exogenous alpha-amylase, either at optimum (35%) or sub-optimum (27%) protein levels, on blood glucose, and the key metabolic enzymes of glycolysis (hexokinase, HK), gluconeogenesis (glucose-6 phosphatase, G6Pase and fructose-1,6 bisphosphatase, FBPase), lipogenesis (glucose-6 phosphate dehydrogenase, G6PD) and amino acid metabolism (alanine amino transferase, ALT and aspartate amino transferase, AST) in Labeo rohita. Three hundred and sixty juveniles (average weight 10 +/- 0.15 g) were randomly distributed into 12 treatment groups with each of two replicates. Twelve semi-purified diets containing either 35 or 27% crude protein were prepared by including G or NG corn as carbohydrate source with different levels of microbial alpha-amylase (0, 50, 100 and 150 mg kg(-1)). The G corn fed groups showed significantly higher (P < 0.05) blood glucose and G6PD activity, whereas G6Pase, FBPase, ALT and AST activity in liver was higher in the NG corn fed group. Dietary corn type, alpha-amylase level in diet or their interaction had no significant effect (P > 0.05) on liver HK activity, but the optimum crude protein (35%) fed group showed higher HK activity than their low protein counterparts. The sub-optimum crude protein (27%) fed group showed significantly higher (P < 0.05) G6PD activity than the optimum protein fed group, whereas the reverse trend was observed for HK, G6Pase, FBPase, ALT and AST activity. Addition of 50 mg alpha-amylase kg(-1) feed showed increased blood glucose and G6PD activity of the NG corn fed group, whereas the reverse trend was found for G6Pase, FBPase, ALT and AST activity in liver, which was similar to that of the G or NG corn supplemented with 100/150 mg alpha-amylase kg(-1) feed. Data on enzyme activities suggest that NG corn in the diet significantly induced more gluconeogenic and amino acid metabolic enzyme activity, whereas G corn induced increased lipogenic enzyme activity. Increased amino acid catabolic enzyme (ALT and AST) activity was observed either at optimum protein (35%) irrespective of corn type or NG corn without supplementation of alpha-amylase irrespective of protein level in the diet.

Download full-text


Available from: Asim K Pal, Apr 13, 2015
  • Source
    • "Additionally, the authors reported an increased activity of intestinal amylase and proteases in nongelatinized diets supplemented with 50 mg α-amylase kg −1 (Kumar et al., 2006c). The addition of α-amylase also increased blood glucose and glucose-6-phosphate dehydrogenase activity in the liver; whereas, activities of glucose-6-phosphatase, fructose-1,6-biphosphatase, alanine aminotransferase and aspartate aminotransferase were reduced (Kumar et al., 2009). Farhangi and Carter (2007) determined the effect of enzyme supplementation (Energex™ [hemicellulases], Bio-Feed™ [protease] and Alpha galactosidase™ [α-galactosidase]) of dehulled lupin-based diets on rainbow trout performance. "
    [Show abstract] [Hide abstract]
    ABSTRACT: A current priority in the aquaculture industry is the replacement of fishmeal with alternative feedstuffs, including plant-based protein ingredients, to ensure its sustainability. However, most plant-based feedstuffs have a wide variety of anti-nutritional factors, which may impair nutrient utilization, interfering with fish performance and health. The use of exogenous enzymes as feed additives to improve nutrient digestibility of plant-based feedstuffs has been researched extensively in poultry and swine. In aquaculture, the use of phytase to improve phosphorus utilization has emerged quite readily. However, the use of carbohydrase enzymes has not been as nearly as common in aquatic species, despite their promising effects in improving nutrient digestibility by hydrolyzing non-starch polysaccharides present in plant feedstuffs. Based on the information gathered in this review, supple-mentation of exogenous carbohydrases to plant-based fish diets should improve nutrient digestibility and reduce nutrient excretion. On the other hand, the effects of exogenous carbohydrases on fish performance are still unclear due to the difficulty in cross-study comparisons. Overall, based on the information gathered in this review, it is clear that research on exogenous carbohydrase supplementation in aquaculture nutrition is not extensive. According to promising results and opportunities found in other non-ruminant animals, and favorable effects found in aquaculture species studied to date, it may be significant to increase research on this subject because it could be a useful tool to improve and sustain commercial aquaculture.
    Full-text · Article · Jan 2015 · Aquaculture
  • Source
    • "Indeed, omnivorous fish (such as common carp, Indian major carps, and many catfish) and herbivorous fish (Nile tilapia) are relatively tolerant and effectively use dietary carbohydrates. This observation is illustrated by the absence of negative effects on growth and on postprandial glycaemia in these fish species fed with up to 30–50 % of carbohydrates (Kumar et al. 2009; Panserat et al. 2000c; Tan et al. 2009). Moreover , glucose tolerance tests with omnivorous fish show reduced glycaemic increases that exist for a shorter period of time than in carnivorous fish confirming a more efficient use of glucose by these species (see Figs. 3, 4) (Legate et al. 2001; Moon 2001; Peres et al. 1999; Polakof et al. 2011f). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Teleost fishes represent a highly diverse group consisting of more than 20,000 species living across all aquatic environments. This group has significant economical, societal and environmental impacts, yet research efforts have concentrated primarily on salmonid and cyprinid species. This review examines carbohydrate/glucose metabolism and its regulation in these model species including the role of hormones and diet. Over the past decade, molecular tools have been used to address some of the downstream components of these processes and these are incorporated to better understand the roles played by carbohydrates and their regulatory paths. Glucose metabolism remains a contentious area as many fish species are traditionally considered glucose intolerant and, therefore, one might expect that the use and storage of glucose would be considered of minor importance. However, the actual picture is not so clear since the apparent intolerance of fish to carbohydrates is not evident in herbivorous and omnivorous species and even in carnivorous species, glucose is important for specific tissues and/or for specific activities. Thus, our aim is to up-date carbohydrate metabolism in fish, placing it to the context of these new experimental tools and its relationship to dietary intake. Finally, we suggest that new research directions ultimately will lead to a better understanding of these processes.
    Full-text · Article · Apr 2012 · Journal of Comparative Physiology B
  • Source
    • "Energy production through this intermediate takes place either by its entering to the Krebs cycle or by its oxidation. The liver is the main site of amino acid deamination in many fish species Aquacult Int (2010) 18:859–868 865 studied so far (Fynn-Aikins et al. 1993; Enes et al. 2006; Kumar 2009). There are, in addition, reports of muscle aminotransferase activity in fishes (Sarma et al. 2009). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The effect of higher packing density and increased duration of transport on the survival and key metabolic enzymes of Labeo rohita fry was investigated. L. rohita fry (length 40±5mm, weight 0.60±0.13g) were packed in two different densities 40 and 80g/l and sampled at 0, 12, 24, and 36h after packing. Results showed that packing density and length of confinement severely affected the survival of the fry. The whole-body glucose level and the activities of the enzymes, lactate dehydrogenase (LDH), malate dehydrogenase (MDH), glucose-6-phosphatase (G6Pase), fructose-1, 6-bisphosphatase (FBPase), aspartate amino transferase (AST), alanine amino transferase (ALT), and adenosine triphosphatase (ATPase) assayed from the fish whole-body significantly (P<0.05) increased due to increase in the length of the confinement. However, acetylcholine esterase (AchE) activity decreased significantly (P<0.05) with increase in the length of confinement. Similarly, higher packing density also significantly (P<0.05) increased the glucose level and activities of all these enzymes (except AchE). The results revealed that both higher packing density and increased transportation duration mobilize protein resources for glucose production via gluconeogenesis and subsequently activate the glycolysis pathway for energy. The rise in the ATPase activity indicates disruption of the osmoregulatory function and the role of this enzyme in ameliorating it. Overall results suggest that normally practiced packing density of 40g/l is optimum up to 24-h duration for seed transportation. KeywordsTransportation-Packing density-Metabolic enzymes-Stress
    Full-text · Article · Aug 2010 · Aquaculture International
Show more