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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetics, Physiology, and Health Research to Improve Catfish Production

Location: Warmwater Aquaculture Research Unit

Title: Mitochondrial fuction and growth in channel catfish strain and diet effects

Authors
item Ashame, Martha -
item Eya, Jonathan -
item Pomeroy, Charles -
item Manning, Bruce -
item Peterson, Brian

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 5, 2010
Publication Date: February 1, 2011
Citation: Ashame, M.F., Eya, J.C., Pomeroy, C.F., Manning, B.B., Peterson, B.C. 2011. Mitochondrial fuction and growth in channel catfish strain and diet effects. Meeting Abstract. P. 19.

Interpretive Summary: An experiment was conducted to evaluate the effects of commercial diets (32/4 or 36/6 percent protein/fat) and channel catfish strains (A, B, C, D, E, or F) on feed efficiency (FE), mitochondrial respiratory chain enzyme activities and gene expression levels in the liver, muscle, and intestine. The analyses of mitochondrial respiratory chain enzyme activities and gene expression analyses were performed on strains C and D with the lowest and highest FE. Mitochondrial complex enzyme activities showed that the activities of the liver mitochondrial complexes (I, II, III, IV) were all lower in low FE compared with those in high FE strain. The activities of intestine mitochondrial complexes (II, III, IV) were all lower in low FE compared with those in high FE with the exception of intestine complex I which was numerically higher but not significant for high FE compared to low FE strain. The activities of the muscle mitochondrial complexes (I, II III) were not affected by strain; however, the activity of complex IV in the muscle was higher for the high FE than for the low FE. There were considerable differences in enzyme activity between the diets for muscle mitochondrial complex I, liver complex II, and muscle complex IV. The effect of strain on the expression of the five selected genes in liver, intestine, and muscles showed an up-regulation of ND1 (NADH dehydrogenase) in the liver and its down-regulation in the intestine and muscle for high FE strain compared to low FE. Cytochrome B (CYTB) gene was down-regulated in the intestine and muscles in high FE but was not affected in the liver. This study provides the first information regarding the effects of mitochondrial respiratory chain activities and FE in channel catfish. Knowledge gained from this study will be used to select catfish for improved FE.

Technical Abstract: A 2 x 6 factorial experiment was conducted to evaluate the effects of commercial diets (32/4 or 36/6 percent protein/fat) and channel catfish strains (A, B, C, D, E, or F) on the growth performance, mitochondrial respiratory chain enzyme activities and gene expression levels in the liver, muscle, and intestine. The analyses of mitochondrial respiratory chain enzyme activities and gene expression analyses were performed on strains C and D with the lowest and highest feed efficiency. Results indicate that feed consumption per fish and feed efficiency (FE) were significantly affected by the fish strain but not by diets. Feed intake was significantly (P<0.05) different between strain C and the rest of the five strains. Strain D had the highest FE compared to strain C that had the least FE. Data regarding mitochondrial complex enzyme activities showed that the activities of the liver mitochondrial complexes (I, II, III, IV) were all significantly lower in low FE compared with those in high FE strain. When expressed as a percentage of high FE, low FE complex activities ranged from 35% lower (for liver complex II) to 26% lower (for complex IV) with 34 and 28% reductions for complexes I and III, respectively. The activities of intestine mitochondrial complexes (II, III, IV) were all significantly lower in low FE compared with those in high FE with the exception of intestine complex I which was numerically higher but not significant for high FE compared to low FE strain. The activities of the muscle mitochondrial complexes (I, II III) were not significantly (P>0.05) affected by strain, however, the activity of complex IV in the muscle was significantly higher (P<0.0001) for the high FE than for the low FE. There were considerable differences in enzyme activity between the diets for muscle mitochondrial complex I (P=0.0107), liver complex II (P=0.0004), and muscle complex IV (P=0.0169). A significant diet X strain interaction effect was only observed in the liver for complex I (P=0.0462). The effect of strain on the expression of the five selected genes in liver, intestine and muscles showed a significant up-regulation of ND1 (NADH dehydrogenase) in the liver (P = 0.0186) and its down-regulation in the intestine (P < 0.0001) and muscle (P = 0.0001) for high FE strain compared to low FE. Cytochrome B (CYTB) gene was significantly down-regulated in the intestine (P = 0.0008) and muscles (P = 0.0205) in high FE but was not significantly affected in the liver. Diet had no significant effect (P > 0.05) on the expression of genes in the liver and muscles of both strains.

Last Modified: 12/20/2014
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