Optimal dietary carbohydrate‐to‐lipid ratios for silvery‐black porgy (Sparidentex hasta) juveniles |
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Authors: | M. Torfi Mozanzadeh V. Yavari J.G. Marammazi N. Agh E. Gisbert |
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Affiliation: | 1. Fisheries Department, Faculty of Marine Natural Resources, Khorramshahr Marine Science and Technology University, Khorramshahr, Iran;2. South Iranian Aquaculture Research Center, Ahwaz, Iran;3. Artemia and Aquatic Research Institute, Urmia University, Urmia, Iran;4. IRTA, Centre de Sant Carles de la Rápita (IRTA‐SCR), Unitat de Cultius Experimentals, Sant Carles de la Rápita, Spain |
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Abstract: | Four isonitrogenous diets containing different carbohydrate:lipid (CHO:L) ratios (0.3, 0.6, 1.1 and 1.8) were tested in triplicate groups (16 fish per replicate) of silvery‐black porgy juveniles for 8 weeks. Growth performance was not affected by different dietary CHO:L ratios (P > 0.05); however, the viscerosomatic index, the intraperitoneal fat, whole‐body lipid, energy and n‐3 long chain polyunsaturated fatty acids levels increased with decreasing dietary CHO:L ratios (P < 0.05). Fish fed with 1.8 CHO:L diet had the lowest apparent digestibility coefficients of protein and lipid, as well as the lowest plasma haemolytic and lysozyme activities (P < 0.05). Red blood cell counts and plasma glucose levels were higher in fish fed with 1.1 and 1.8 CHO:L ratio diets than in the other groups (P < 0.05). Plasma alkaline phosphatase and alanine aminotransferase, as well as the level of lipid peroxidation and total antioxidant capacity in the liver and plasma increased as dietary CHO:L ratios decreased (P < 0.05). The results of the current study indicated that the diets with CHO:L ratios between 0.6 and 1.1 are optimal for silvery‐black porgy, whereas higher ratios may result in hyperglycaemia and immune suppression, and lower CHO:L ratios may lead to oxidative stress and liver dysfunction. |
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Keywords: | carbohydrate:lipid ratios haemato‐immunological parameters oxidative status plasma biochemical parameters sparidae |
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