Rearing of the Nile tilapia (Oreochromis niloticus) on diets containing cotton seed meal enriched with vitamin E

Soltan, Magdy; Saudy, Abdel-Nasser; Fath El-Bab, Ahmed

doi:10.21608/ejabf.2011.2080

Rearing of the Nile tilapia (Oreochromis niloticus) on diets containing cotton seed meal enriched with vitamin E

Document Type : Original Article

Authors

¹ Faculty of Agriculture, Moshtohor, Banha University, Egypt.

² National Organization for Drug Control and Research, Egypt

³ Central Laboratory for Aquaculture Research - Abbassa, Sharkyia governorate

10.21608/ejabf.2011.2080

Abstract

The present experiment was conducted to evaluate the effect of α-tocopherol as an antioxidant for avoiding the side effects of incorporation of cottonseed meal (CSM) in the diet of the Nile tilapia as a replacer of fish meal (FM). Two
diets were prepared; the first one contained fish meal and was considered as a control, in the second diet, FM was completely replaced by CSM. The second diet was divided into ten parts, the first one is a control and the other 9 diets were enriched with increased levels of vitamin E (1, 5, 10, 15, 20, 25, 30, 35 and 40 times of gossypol in CSM). Each diet was offered in three aquaria (3 replicates for each diet) and each aquarium was stocked with 25 fish (2.0-2.1g). Results are summarized in the following:
- The highest average body weight (9.91 g) was recorded for the control group fed on the
basal diet (contained FM) and the lowest BW (5.66 g) was obtained for fish fed the diet
D2 in which FM was completely replaced by CSM without vitamin E. Incorporation of
vitamin E in the experimental diet significantly improved the BW. Similar trend was
observed for the other growth performance parameters body length (BL), weight gain
(WG) and specific growth rate (SGR).
- The best feed conversion ratio (FCR) was recorded for fish group fed on the diets D1
and D3 which significantly differed from values recorded for the other treatments. The
worst FCR was recorded in fish group fed on the diet D2 in which FM was completely
replaced by CSM without addition of vitamin E. Incorporation of vitamin E in the
experimental diets improved FCR specially fish group fed on the diet D3.
- Protein content of the whole fish body ranged between 41.33 to 50.97% and the
differences were significant. Fat content of fish fed the diet D2 significantly higher
than those obtained for fish fed the other groups. Compared to the two control diets
D1 and D2 all vitamin levels in the experimental diets increased ash content of the
fish whole body and the graded levels of vitamin E in the diets significantly altered
the ash content of tilapia fish.
- The highest values for hematocrite (Ht) and haemoglobin (Hb) were obtained for
fish fed on the control diet (D1). Incorporation of vitamin E in the experimental
diets at increasing levels significantly affected Hb and Ht. Compared to the
control group (Diet1) aspartate transaminase (AST) and alanine transaminase
(ALT) levels significantly increased fish groups fed on the other experimental
diets.

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