Adding Iranian oak acorn (Quercus brantii) to the diet of common carp (Cyprinus carpio Linnaeus, 1758) and its effects on growth performance, carcass composition and resistance to salinity stress

At this study, the effects of adding Iranian acorn flour on growth performance, carcass composition and resistance to salinity stress of common carp were investigated. Experimental diets included: 1) without acorn and not autoclaved diet; 2) without acorn and autoclaved diet for 2 minutes; 3) without acorn and autoclaved diet for 10 minutes; 4) with 10 percent acorn and not autoclaved diet; 5) with 10 percent acorn and autoclaved diet for 2 minutes; 6) with 10 percent acorn and autoclaved diet for 10 minutes. After 6 weeks results showed that weight and total length in the treatment 2 were higher than the rest. This increase was significantly higher than all treatments except 4 (p<0.05). Autoclaving reduced carcass protein and increased its moisture contents significantly and this effect intensified with an increase in the duration of autoclaving. Short-term autoclaving caused a significant increase in carcass fat while long-term autoclaving resulted its significant reduction. Adding acorn flour into the diet reduced amounts of carcass protein and fat and increased its moisture content significantly. Accordingly, although there was no significant difference between fish weights of treatments 1 and 4, replacement of wheat flour with acorn flour at 10% of diet was undesirable. In not autoclaved or short-term autoclaved diets, oak acorn flour reduced carcass ash significantly. In salinity stress test, the highest and lowest survival time were observed in the treatment 2 and treatments 1 and 6, respectively. When autoclaving (heat) was used in food production, the addition of oak acorn flour to the diet significantly reduced survival time at the salinity stress. Overall, considering the growth performance, carcass composition and resistance of carp to stress, it is recommended to study oak acorn flour consumption at levels less than 10% of the diet.