Preliminary results upon the effect of various dietary lipid sources on growth and health status of African catfish, Clarias gariepinus
Pector, R.; Caers, G.; van Houdt, R.; Ollevier, F.P. (1993). Preliminary results upon the effect of various dietary lipid sources on growth and health status of African catfish, Clarias gariepinus, in: Seventh forum for applied biotechnology, PAND, Gent 30 September - October 1993, abstracts. pp. 55 In: (1993). Seventh forum for applied biotechnology, PAND, Gent 30 September - October 1993, abstracts. RUG: Gent. 150 pp., more |
| Available in | Authors | | Document type: Conference paper
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| Authors | | Top | - Pector, R.
- Caers, G.
- van Houdt, R., more
- Ollevier, F.P., more
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| Abstract | Six artificial diets, which only differed in their lipid composition, were administered in duplo to African catfish (± 8.2 g) at 28°C. The lipid sources used in the respective diets were: 1) safflower oil; 2) linseed oil; 3) soybean oil; 4) olive oil; 5) menhaden oil and 6) cocos fat. The following variables were used to study the evolution of the health status of the fish during the experiment: a) antibody production, b) hematocrit, c) spleen-index (weight of the spleen/total weight of the body x 100) and d) index of the head-kidneys (weight of the head-kidneys/total weight of the body x 100). After 89 days, growth was poor in all experimental groups, probably due to the low protein concentration of the diets. The highest mean weights were obtained with the diets in which soybean oil and olive oil were incorporated. Feeding diets supplemented with linseed oil and menbaden oil resulted in the significantly lowest mean weights. Antibody production capacity decreased in all groups during the experiment. After 3 months the antibody titer obtained in fish fed the diet with linseed oil was relatively low compared with the other experimental groups. Hematocrit values obtained in the different groups were low. After 1 month the diet with soybean oil or olive oil resulted in the highest hematocrit percentages, while the lowest were obtained in fish fed diet 2 or 6. During the second and third month no differences were noticed between the hematocrit values of the different groups. The spleen-index and the index of the head-kidneys remained more or less constant during the experiment and were out influenced by the administered diet. Since weight gain was rather low, conclusions upon the effect of the dietary lipid source on growth must be drawn carefully. Nevertheless, the results indicated that a relatively high concentration of 18:1n-9 (in olive oil and soybean oil) in the diet enbances growth at 28°C. Lipid sources rich in 18:3n-3 or n-3 highly unsaturated fatty acids (in respectively linseed oil and menhaden oil) on the contrary, have a negative effect on weight gain of African catfish. The decreasing antibody production capacity and the low hematocrit values can probably also be ascribed to the low protein content of the diets, which may have resulted in a poorer health status at the end of the experiment. |
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