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Nutritional Regulation (nutritional + regulation)
Selected AbstractsNutritional regulation of intestine morphology in larval cyprinid fish, silver bream (Vimba vimba)AQUACULTURE RESEARCH, Issue 12 2008Teresa Ostaszewska Abstract The present study includes the evaluation of morphological changes in the digestive tract of larval, stomachless fish silver bream (Vimba vimba) fed with various diets , live Artemia nauplii, commercial feed Aglo Norse (NOR) and semi-purified formulated diets: casein,gelatin (CG), dipeptide-protein (50P), dipeptide (100P), no-arginine dipeptide diet (100Pw/oArg) and a free amino acid (FAA) mixture diet. The supranuclear area of enterocytes in the posterior intestine contained enlarged absorptive vacuoles in the FAA, 100P and 100Pw/oArg groups, compared with the remaining groups. Hepatocytes' cytoplasm in fish fed with FAA, 100P and 100Pw/oArg contained mainly glycogen, and no lipid vacuoles were found. Fish fed with 100Pw/oArg showed the lowest hepatocyte surface areas while in those fed with 50P, the largest nuclei diameters were observed. Fish fed with Artemia, NOR and CG diets showed significantly (P<0.05) higher number of proliferating cells compared with the remaining groups. Chromogranin A staining showed endocrine-immunoreactive cells (CgA-IR) in the taste buds in the oral cavity and in the enterocytes' supranuclear areas of the anterior and posterior intestine. We conclude that the growth rate and histological examination of the digestive tract in the 50P group of silver bream showed no nutritional deficiency. [source] The effects of nutritional imbalance on compensatory feeding for cellulose-mediated dietary dilution in a generalist caterpillarPHYSIOLOGICAL ENTOMOLOGY, Issue 2 2004Kwang Pum Lee Abstract. The interactive effects of macronutrient balance [protein (P) : carbohydrate (C) ratio] and dietary dilution by cellulose on nutritional regulation and performance were investigated in the generalist caterpillar Spodoptera littoralis (Boisduval). Caterpillars were reared through the final stadium on one of 20 foods varying factorially in macronutrient content (P + C%: 42, 33.6. 25.2 or 16.8%) and P : C ratio (5 : 1, 2 : 1, 1 : 1, 1 : 2 or 1 : 5). The animals compensate by eating more of diluted foods, but suffer reduced nutrient intake in proportion to the degree of dilution. Increase in food intake with dilution is greater on balanced than imbalanced foods and this is reflected in greater reduction of dry pupal mass with dilution in the latter. Whereas dilution results in a reduction in the amount of whichever macronutrient is in excess in the food, by contrast, the ability to compensate for the deficient macronutrient in the food is unaffected by nutrient imbalance. Excess protein intake due to nutritional imbalance (diets with high P : C ratios) results in a regulatory decrease in the efficiency of retention of ingested nitrogen relative to restricted protein intake on oppositely imbalanced foods (low P : C ratios). By contrast, decreased protein intake due to dietary dilution is associated with a non-regulatory reduction in the efficiency of retention, irrespective of P : C ratio. Dilution is similarly associated with reduced utilization efficiency of ingested carbohydrate. The ecological implications of these results are discussed. [source] Molecular cloning, characterization and nutritional regulation of key enzymes required for the effective utilization of marine wax esters by Atlantic salmon (Salmo salar L.)AQUACULTURE NUTRITION, Issue 5 2010M. MINGHETTI Abstract Previous studies had shown that wax ester-rich lipid extracted from calanoid copepods could be a useful alternative to fish oil as a provider of long-chain n-3 polyunsaturated fatty acids in diets for use in salmon aquaculture. Effective utilization of wax ester requires digestion and metabolism in the intestine with the fatty alcohol component being oxidized to fatty acid in intestinal cells through the combined activities of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). We studied wax ester utilization in Atlantic salmon using a candidate gene approach, focusing on ADH and ALDH as sequence information was available for these genes, including fish sequences, facilitating isolation of the cDNAs. Here, we report on the isolation and cloning of full-length cDNAs for ADH3 and ALDH3a2 genes from salmon intestinal tissue. Functional characterization by heterologous expression in the yeast, Saccharomyces cerevisiae, showed the products of these cDNAs had long-chain ADH and ALDH enzyme activities. Thus, ADH3 was capable of oxidizing long-chain fatty alcohol, and ALDH3a2 was capable of oxidizing long-chain fatty aldehyde to the corresponding fatty acid. The genes were highly expressed in intestinal tissue, particularly pyloric caeca, but their expression was not increased in salmon fed dietary copepod oil in comparison to fish fed fish oil. [source] Hormonal and nutritional regulation of insect fat body development and functionARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 1 2009Ying Liu Abstract The insect fat body is an organ analogue to vertebrate adipose tissue and liver and functions as a major organ for nutrient storage and energy metabolism. Similar to other larval organs, fat body undergoes a developmental "remodeling" process during the period of insect metamorphosis, with the massive destruction of obsolete larval tissues by programmed cell death and the simultaneous growth and differentiation of adult tissues from small clusters of progenitor cells. Genetic ablation of Drosophila fat body cells during larval-pupal transition results in lethality at the late pupal stage and changes sizes of other larval organs indicating that fat body is the center for pupal development and adult formation. Fat body development and function are largely regulated by several hormonal (i.e. insulin and ecdysteroids) and nutritional signals, including oncogenes and tumor suppressors in these pathways. Combining silkworm physiology with fruitfly genetics might provide a valuable system to understand the mystery of hormonal regulation of insect fat body development and function. © 2009 Wiley Periodicals, Inc. [source] | ||||||||||