Effects of different levels of canola meal on growth, body composition and biochemical parameters in rainbow trout (Oncorhynchus mykiss).
2009
Gorji Pur, E`yn Ol-Lah | Shafaei Pur, Ariya | Hosseini, Mohammad Reza | Asadi, Mahmud | Gandom Kar, Habib Ol-Lah | Taheri Mir Qaed, A`li
Rainbow trout (initial body weight 4.16 ± 0.25 g) were fed diets (crude protein 42%gross energy 4400 Kcal/kg DMcrude fat 10%) containing graded levels of either a canola meal (CP 35% DM). A growth trial was conducted over 16 weeks at a water temperature of 12 ± 1 °C. At the end of the growth trial, in addition to body composition analyses, plasma triiodothyronine (T3) and thyroxin (T4), cholesterol and liver fatty acid composition were measured. Replacement of fish meal with canola meal (10 to 57% replacement) was not significant affect on growth performance (P0.05). At 16th week, plasma cholesterol levels were reduced in fish fed all diets in comparison to 8th week. Plasma T4 levels were significantly higher in the canola meal-fed fish sampled after 16 weeks, but no significant differences in T3 levels were obtained (P0.05). Proximate composition was affected by dietary treatments. The liver fatty acid composition reflected that of the diet with a higher level of polyunsaturated (n-6) fatty acids in fish fed diet canola meal and a higher content in n-3/n-6 ratio in fish fed diet without canola meal. With increasing canola meal in diets, was reduced the cost of final food. This study shows that canola meal has potential to replace substantial levels of fish meal in diets for carnivorous fish without compromising performance.
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