Aquaculture Nutrition doi: 10.1111/j.1365-2095.2009.00669.x 2010 16; 335342 1 1,2 1 State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, the Chinese Academy of Sciences, Wuhan, Hubei, China; Aquaculture Divisions, E-Institute of Shanghai Universities, Shanghai, China The eects of aatoxin B1 (AFB1) on growth, physiological responses and histological changes were investigated in juvenile gibel carp (Carassius auratus gibelio) Triplicate groups of gibel carp (3.53 0.02 g) were fed seven semipuried diets (Diet to 7) containing 3.20, 5.37, 7.08, 9.55, 12.70, 17.90 and 28.60 lg AFB1 kg)1 diet for months The results showed sh weight gain fed Diet was 112.6% of that of control group (Diet 1) after months, but there was no signicant dierence of weight gain between sh fed Diet and the control group Alanine aminotransferase (ALT) of sh hepatopancreas fed Diet was signicantly higher than the control group (P < 0.05), but no signicant dierence was observed in ALT activities of the sh fed with more than 10 lg AFB1 kg)1 (Diet 4, 5, and 7) No signicant histological lesions were identied between the control and increasing AFB1 treatments AFB1 accumulated in hepatopancreas was logarithmically related to the dietary AFB1 levels, and AFB1 also accumulated in muscles and ovaries of gibel carp fed Diet to Diet The present results indicated that sh fed with more than 10 lg AFB1 kg)1 diet showed impaired physiological responses and more AFB1 residue of muscles and ovaries above the safety limitation of European Union KEY WORDS: aatoxin B1, alanine aminotransferase, Carassius auratus gibelio, residue, weight gain Received 18 December 2008, accepted 13 March 2009 Correspondence: Dr Dong Han, State Key Laboratory of Freshwater and Biotechnology, Institute of Hydrobiology, the Chinese Academy of Sciences, Wuhan, Hubei, 430072, China E-mail: hand21cn@ihb.ac.cn Aatoxin, a polycyclic aromatic hydrocarbon, is produced mainly by Aspergillus avus and Aspergillus parasiticus, ể 2009 The Authors Journal compilation ể 2009 Blackwell Publishing Ltd which occurs naturally in several important plant feedstus Aatoxin B1 (AFB1) is the most toxic compound produced by these moulds The toxicity of AFB1 has been best reported for poor growth, hepatotoxic, nephrotoxic, carcinogenic, mutagenic, teratogenic and cytotoxic properties (Halver 1969; Jantrarotai & Lovell 1990; Chavez-Sanchez et al 1994; Sahoo et al 1996; Santacroce et al 2008) In studies of carcinogenic eect, the liver of sh is one of the organs most aected by dietary AFB1 (Hendricks et al 1985; McKean et al 2006) AFB1 has been found to be a potent immunomodulator in endotherms (Ottinger & Kaattari 1998; Sahoo & Mukherjee 2001) AFB1 is well known for the highest potency as a toxin and is classied as group I carcinogen by International Agency for Research on Cancer The consumption of AFB1 contaminated feed by sh brings contamination of products, which may result in secondary contamination for human from eating meat with residues of AFB1 (Madhusudhanan et al 2006) Globally, there are strict regulations with regard to the safe limits of AFB1 in domestic animal feed and food items (Gowda et al 2007) The European Union established lg kg)1 as the maximum allowable concentration of AFB1 in human food (Food and Agriculture Organization (FAO) 2004) and lg kg)1 as the limit of AFB1 in feed (van Eijkeren et al 2006) Under FDA regulations, upper limit of most feed ingredients and nonruminant feeds is 20 lg aatoxin kg)1 (Food and Drug Administration (FDA) 1989) In many countries including China, there are no ocial safe levels for aatoxins in sh feeds Although AFB1 has been studied in dierent shes, such as salmonoids (Hendricks et al 1977), channel catsh (Jantrarotai & Lovell 1990) and Nile tilapia (Tuan et al 2002), most of these reports were focused on the high AFB1 levels Actually, dietary AFB1 levels could be very low due to good care of dietary ingredients Therefore, it is very important and necessary to make clear the eect of low dietary AFB1 levels on sh Gibel carp, an omnivorous species, is an important aquaculture species in China and the annual production is more than million tonnes Increased use of plant ingredients in aquafeed for gibel carp has intensied the potential for aatoxicosis The purpose of the present study is to investigate the eects of low dietary AFB1 levels on growth, physiological, histological characteristics and tissue AFB1 residue in gibel carp Table Supplemented and determined aatoxin B1 levels of the experimental diets Experimental diets Diet Diet Diet Diet Diet Diet Diet Supplemented AFB1 (lg kg)1) Determined AFB1 (lg kg)1) 10 20 40 80 3.20 5.37 7.08 12.70 17.90 28.60 9.55 sh oil were used as the main protein and lipid source Diets were made into pellets (2 mm, diameter), oven-dried at 60 C and stored at C until fed Puried aatoxin B1 was purchased from Sigma (St Louis, MO, USA) According to the method of Sahoo & Mukherjee (2003), AFB1 was rst dissolved in chloroform and sh oil was then added into the mixture After adding oil, the chloroform was allowed to evaporate Seven experimental diets (Diet 1-7) were formulated to contain 3.20, 5.37, 7.08, 9.55, 12.70, 17.90 and 28.60 lg AFB1 kg)1 diet, which were isonitrogenous (394.7 g kg)1 crude protein), isoenergetic (16.75 kJ g)1 diet) and isolipidic (85.4 g kg)1 crude lipid) Diet is the control diet without supplementing puried aatoxin B1 The formulation of the basal diet and the determined AFB1 levels of the experimental diets are shown in Tables & White sh meal and Table Formulation and chemical composition of the basal diet (in dry weight) Ingredient White fishmeal (from USA) Corn starch a-Starch Fish oil Mineral premix1 Vitamin premix2 Vitamin C Cellulose Carboxymethyl cellulose Chemical composition (in dry matter) Crude protein Crude fat Gross energy (kJ g)1) Content (g kg)1) 570.0 220.0 30.0 25.0 50.0 3.9 1.1 70.0 30.0 394.7 85.4 16.75 Mineral premix (mg kg)1 diet): NaCl, 500; MgSO4ặ7H2O, 7500; NaH2PO4ặ2H2O, 12500; KH2PO4, 16000; Ca (H2PO4) 2ặH2O, 10000; FeSO4, 1250; C6H10CaO6ặ5H2O, 1750; ZnSO4ặ7H2O, 176.5; MnSO4ặ 4H2O, 81; CuSO4ặ5H2O, 15.5; CoSO4ặ6H2O, 0.5; KI, 1.5; starch, 225 Vitamin premix (mg kg)1 diet): thiamin, 20; riboflavin, 20; pyridoxine, 20; cyanocobalamine, 2; folic acid, 5; calcium patotheniate, 50; inositol, 100; niacin, 100; biotin, 5; starch, 3226; Vitamin A, 110; Vitamin D3, 20; Vitamin E, 100; Vitamin K3, 10; Choline chloride, 1100 Gibel carp was obtained from the hatchery of the Institute of Hydrobiology, the Chinese Academy of Sciences Before the experiment, the juveniles were acclimated to the experimental condition for weeks During the acclimation, sh were fed twice daily with the control diet The experiment was carried out in a ow-through system consisting of 21 polythene tanks (60 ã 47 ã 50 cm, water volume: 140 L) Water owing rate into each tank was 0.2 l min)1 During the experiment, water temperature was maintained at 24 C The dissolved oxygen content was kept above 7.5 mg O2 L)1, pH between 7.0 and 7.6, ammonia-N less than 0.5 mg L)1, and the photoperiod was 12D : 12L with the light period from 0800 to 2000 Before the experiment, sh were deprived of feed for day Twenty-three sh (3.53 0.02 g ind)1) were bulk weighed and randomly transferred into each tank During the experiment, the sh were fed to apparent satiation twice a day (0900, 1500), and daily feed intake was recorded The faeces were removed by siphoning twice a day just before each feeding Fish in each tank were batch-weighed every month after 1-day food deprivation to evaluate the toxic eect of dietary AFB1 on growth performance The trial lasted for months At the end of the experiment, 10 sh per tank were anesthetized with MS-222, and the length and weight of sh were measured Blood was withdrawn from dorsal vessels using the syringe, and centrifuged at 4000 g (4 C) for 15 to get the serum The hepatopancreas of four sh were collected on ice, weighed and stored in liquid nitrogen for enzyme determination The muscles, hepatopancreas, and ovaries of six sh were pooled on ice and used for AFB1 residue analysis Another three sh per tank were sampled for histological studies ể 2009 The Authors Journal compilation ể 2009 Blackwell Publishing Ltd Aquaculture Nutrition 16; 335342 Serum analysis Serum superoxide dismutase (SOD) activity was determined using the method of McCord & Fridovich (1969) One unit of SOD activity is described as the amount of sample required to cause 50% inhibition of the rate of reduction of cytochrome c by O2) Serum catalase (CAT) activity was measured using the method of Aebi (1984) in which the initial rate of hydrogen peroxide decomposition is determined One unit of catalase activity was dened as the amount of enzyme that catalysed the decomposition of 1.0 lmol of H2O2 per second Hepatopancreas analysis Fish hepatopancreas were thawed, rinsed with 0.65% physiological saline, and then homogenized in ve volumes v/w of ice-cold 0.65% physiological saline using a hand held glass homogenizer on ice The homogenate was centrifuged at 10 000 g for 10 at C The supernatant was stored at C as the crude extract All assays were conducted within 24 h after extraction The enzyme activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured at an absorbance of 505 nm according to the method of Hứrder & Rej (1981) The protein content of the supernatant was determined using Bradford assay with bovine serum albumin as a standard, and the specic activity of the enzymes was dened as activity unit per mg protein enzyme-link immunosorbent assay (ELISA) method using a commercial assay kit (Brins-LivePro Biotechnology Corporation, Beijing, China) For this determination, the absorbance at 490 nm was recorded using a microplate spectrophotometer (PowerWave XS; BioTek Instruments Inc., Winooski, Vermont, USA) The sensitivity of AFB1 measurement was less than 0.01 lg kg)1 Duncanếs multiple range test was used to detect the signicance of dierences of means between groups followed by one-way analysis of variance (ANOVA) Eects with a probability of P < 0.05 were considered statistically signicant The hepatopancreas samples were xed in Bouinếs uid for 12 h and dehydrated in a graded ethanol series The hepatopancreas slices were then embedded in paran, thin sectioned to lm, stained with hematoxylin and eosin (H & E) and observed under light microscopy During the experiment, the average weight gain (WG) of sh was signicantly aected by dietary aatoxin B1 concentrations (Table 3) After month, sh WG increased with the increasing dietary AFB1, and the sh WG fed with highest AFB1 level (Diet 7) was signicantly higher than the low dietary AFB1 groups (Diet or 2) (P < 0.05) After months, no signicant dierence was observed in WG between the highest AFB1 level group (Diet 7) and the others At the end of the experiment, WG of the sh fed Diet was signicant lower than that fed Diet (P < 0.05) Table showed condition factor (CF) in the sh fed Diet was signicantly higher than CF in the other groups (P < 0.05) There was no signicant eect on hepatosomatic index (HSI) and feed conversion ratio (FCR) between all groups (P > 0.05) There was no mortality observed during the experiment Crude protein, lipid and energy content were analysed for the experimental diets Dry matter content was determined by drying to constant weight at 105 C Nitrogen content was analysed by the Kjeldahl method Crude lipid was determined by ether extraction using a Soxtec system (Soxtec System HT, 1043 Extraction Unit, Tecator, Sweden) and energy by bomb calorimeter (Phillipson microbomb calorimeter; Gentry Instruments Inc., Aiken, SC, USA) AFB1 measurement of the experimental diets, muscles, hepatopancreas and ovaries of sh were carried out by the The activities of catalase (CAT), superoxide dismutase (SOD), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of gibel carp fed with dierent dietary AFB1 for months were shown in Table Serum SOD activities of sh fed with more than 10 lg AFB1 kg)1 diet (Diet 4, 5, and 7) were signicantly higher than the control diet (P < 0.05) Hepatopancreas ALT activities of sh fed Diet were signicantly higher than the control (P < 0.05), while the activities of serum CAT and hepatopancreas AST showed no signicant dierence between dierent groups (P > 0.05) ể 2009 The Authors Journal compilation ể 2009 Blackwell Publishing Ltd Aquaculture Nutrition 16; 335342 Table Growth performance of gibel carp fed with different concentrations of AFB1 for months (mean SE)* Average weight gain (%)1 Supplemented AFB1 (lg kg)1) Initial weight (g) month 10 20 40 80 3.52 3.53 3.52 3.54 3.52 3.51 3.54 122.9 127.3 128.6 128.8 130.3 132.5 135.7 0.01 0.01 0.01 0.003 0.02 0.01 0.01 months 3.8a 2.0ab 2.1abc 2.3abc 0.9abc 2.8bc 2.5c 371.5 382.6 389.3 387.8 391.8 401.6 391.8 12.0a 3.4ab 4.2ab 2.4ab 5.4ab 3.8b 17.9ab months 739.0 746.2 736.4 802.6 774.4 842.3 774.7 35.8a 15.8a 10.0a 11.7ab 15.1a 25.9b 12.3a HSI (%)2 CF3 3.87 3.55 3.34 4.10 3.73 3.50 3.56 1.45 1.53 1.60 1.63 1.56 1.76 1.59 0.27 0.14 0.25 0.20 0.33 0.19 0.27 FCR4 0.02a 0.05ab 0.03b 0.03b 0.02ab 0.07c 0.03b 1.26 1.16 1.23 1.14 1.15 1.12 1.16 0.10 0.01 0.05 0.01 0.01 0.02 0.004 * Different superscript letters within each row represent significant differences (P < 0.05) Weight gain = 100 ã (Final weight)initial weight)/(initial weight) HSI (Hepatosomatic index) = 100 ã (liver weight)/(fish weight) CF (Condition factor) = 100 ã final weight (g)/[fork length (cm)]3 FCR (Feed conversion ratio) = total dry feed fed (g)/total wet weight gain (g) Table The activities of catalase (CAT), superoxide dismutase (SOD), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of gibel carp fed with different concentrations of AFB1 for months (mean SE)* In serum Supplemented CAT AFB1 (lg kg)1) (U ml)1) SOD (U ml)1) 10 20 40 80 211.4 238.9 245.2 278.0 285.9 293.0 305.8 2.6 2.0 2.6 1.9 2.0 2.3 2.6 0.34 0.29 0.66 0.31 0.13 0.38 0.29 residue in muscle and ovary was 4.08 and 3.16 lg kg)1 (Fig 3) In hepatopancreas 6.1a 13.9ab 30.7abc 17.1bc 20.1bc 19.8bc 10.4c AST ALT (IU g)1 pro) (IU g)1 pro) 70.1 65.9 69.3 82.4 79.5 67.0 63.5 9.3 10.5 13.4 14.4 13.2 4.6 15.7 153.3 156.2 166.2 205.8 205.1 216.6 244.5 19.2a 11.6a 4.9a 32.0ab 21.6ab 6.8ab 36.5b * Different superscript letters within each row represent significant differences (P < 0.05) After months, no signicant histological lesions were identied in hepatopancreatic tissues of gibel carp between the control and dierent dietary AFB1 groups Hepatocytes and nuclei were uniform in size and shape and prominent cytoplasm was present in most hepatocytes of the control sh and AFB1 treated sh (Fig 1) After months, AFB1 residue in sh hepatopancreas increased signicantly and was logarithmically related to dietary AFB1 (Fig 2) However, AFB1 residue in muscle and ovary of sh was not detected in the control group and Diet Groups of Diet 4, 5, and produced more than lg kg)1 of AFB1 residue in muscles and ovaries, and the highest The phenomenon of hormesis for toxic or harmful substances, a doseresponse characterized by a low dose stimulation and a high dose inhibition, has been widely discussed (Calabrese & Baldwin 1998, 2003; Calabrese 2005, 2008; Murado & Vazquez 2007; Belz et al 2008) In the present study, weight gain of sh fed Diet was 112.6% of that of the control group after months, but there was no signicant dierence of weight gain between sh fed Diet and the control group This growth hormesis response was similar to the results in chickens (Diaz et al 2008) However, decreased growth was reported in many species fed dierent dietary AFB1, which is not agreed to the present study (Boonyaratpalin et al 2001; Tuan et al 2002; Madrigal-Santillan et al 2006; Han et al 2008) The reasons for the dierence were probably that: (1) many reports studied the toxic eects of high dietary AFB1 (Jantrarotai & Lovell 1990; Chavez-Sanchez et al 1994; Boonyaratpalin et al 2001; Tuan et al 2002); (2) many research species were sensitive to even very low dietary AFB1 levels (Lovell 1989; Lim et al 2001); (3) the homesis could be usually elicited for the low response of 1020% (Johnson & Bruunsgaard 1998) Fish fed Diet showed the signicant growth-suppressing eects of AFB1 over time during the experiment, which suggested that the hormesis response could change as experimental time went on The condition factor (CF) expressed the condition of sh, such as the degree of well being, plumpness or fatness, and determined from observed weights and fork length In this study, ể 2009 The Authors Journal compilation ể 2009 Blackwell Publishing Ltd Aquaculture Nutrition 16; 335342 (a) 50 àm (b) (d) (c) 50 àm (e) 50 àm 50 àm 50 àm (f) 50 àm (g) 50 àm Figure Hepatopancreas of gibel carp fed with (a) the control diet, (b) Diet 2, (c) Diet 3, (d) Diet 4, (e) Diet 5, (f ) Diet and (g) Diet for months H&E, Bar = 50 lm there was a signicant increase of CF in sh fed Diet and above and sh fed Diet showed the highest CF It was suggested that sh fed Diet and above grew shorter in shape than the control group In this study, FCR was not signicantly aected by the dietary AFB1 levels Similar ndings were reported for Nile tilapia that FCR was not aected by AFB1 levels as high as 30 mg kg)1 (Chavez-Sanchez et al 1994) The dierent nding in tilapia was reported that FCR of the control was signicantly lower than that of the group fed with 100 lg AFB1 kg)1 diet (Lim et al 2001) This might due to the dietary soybean meal was substituted by the aatoxincontaminated palm kernel meal Aatoxin B1 has been reported to impact the liver of sh (Tuan et al 2002) AST and ALT were used as the ể 2009 The Authors Journal compilation ể 2009 Blackwell Publishing Ltd Aquaculture Nutrition 16; 335342 peroxidation or chromosomal damage through the release of oxygen free radicals (Amstad et al 1984; Shen et al 1994), which suggested that increasing oxidative damage might contribute to the cytotoxic eects of AFB1 These ndings supported the results found in this study that sh consumed more than 10 lg AFB1 kg)1 diet showed no alarming signs except increasing serum SOD activities On the other hand, Rastogi et al (2001) reported that SOD activity in liver of rats was decreased when intraperitoneally administered at a dose of mg AFB1 kg)1 body weight Aflatoxin B1 in hepatopancreas (AH, àg kg1) 40 35 30 25 AH = 13.91 + 18.73 * log10 (AD) R = 0.8976, P < 0.05 20 15 10 0 10 15 20 25 Aflatoxin B1 in diets (AD, àg kg1) 30 Aflatoxin B1 residue in tissues (àg kg1) Figure The relationship between AFB1 in hepatopancreas (AH, lg kg)1) and in diets (AD, lg kg)1) Muscle Ovary In histological studies of AFB1, the liver of sh was one of the organs most aected by dietary AFB1 (Hendricks 1994) However, in this study, no signicant changes were observed in HSI and hepatopancreatic histology of gibel carp among dierent groups, which suggested the low dietary AFB1 could not cause the hepatopancreatic histological changes of gibel carp This was supported by the eects of low dietary AFB1 as 0250 lg kg)1 on Nile tilapia (Tuan et al 2002) and 0100 lg kg)1 on black tiger shrimp (Boonyaratpalin et al 2001), but a concentration as low as 0.5 lg of AFB1 kg)1 diet fed for months had been found to cause liver tumours in rainbow trout (Halver 1969) Our results indicated that gibel carp is much less sensitive than rainbow trout to the histopathological eects of AFB1 (Halver 1969) 10 15 20 25 Dietary aflatoxin B1 (àg kg1) 30 Figure AFB1 residue in muscle and ovary of gibel carp fed with different dietary AFB1 for months, and AFB1 residue in tissues of sh was not detected in the control group and Diet biochemical indicators for hepatic damage (Cheng et al 2001; Allameh et al 2005) In this study, the increase in ALT activity of sh fed with the highest dietary AFB1 was statistically signicant, which suggested that AFB1 slightly damaged the hepatopancreas of gibel carp This result agreed with the previous nding in broilers (Bintvihok & Kositcharoenkul 2006) Similarly, Han et al (2008) also described a marked increase by 9.6% or 13.8% in serum ALT activities of ducks fed the diets containing 20 lg kg)1 or 40 lg kg)1 AFB1-contaminated rice when compared to the value of the control group free of AFB1 The increase in activation of SOD conferred protection against oxidative damage (Mattson et al 1995) Many studies have observed that AFB1 was able to induce lipid A number of studies have reported analysis of aatoxin residues in cattle (Cook et al 1986), broilers (Bintvihok & Kositcharoenkul 2006) and lambs (Fernandez et al 1997) but not in aquatic animal species Ngethe et al (1992) reported that the highest AFB1 disposition was observed in the bile, liver, kidney and pyloric caeca of rainbow trout following oral and intravenous administration over a period of days The nding was in close agreement with this study that AFB1 residue in hepatopancreas was much higher than that in muscles and ovaries On the other hand, Divakaran & Tacon (2000) observed that Aatoxin B1 was not detected in faeces, whole shrimp or tail muscle of Penaeus vannamei when fed with dietary afaltoxin B1 (300, 400 and 900 lg AFB1 kg)1) in weeks Plakas et al (1991) found that AFB1 residue in tissues were rapidly depleted and there was a very low potential for the accumulation of AFB1 and its metabolites in the edible esh of channel catsh through the consumption of AFB1contaminated feed However, concern of indirect AFB1 ể 2009 The Authors Journal compilation ể 2009 Blackwell Publishing Ltd Aquaculture Nutrition 16; 335342 hazard of secondary contamination from eating sh esh for human has been raised (Madhusudhanan et al 2006) In European Union, the regulatory level for AFB1 in foods adopted is ppb posed on risk assessments (Food and Agriculture Organization (FAO) 2004) In this study, AFB1 residue in muscles and ovaries of sh fed with more than 10 lg kg)1 diet was more than ppb The growth hormesis response at low AFB1 levels of the present study indicated that the eect of AFB1 could not be eectively observed from the growth of sh, especially at low concentrations Fish fed with more than 10 lg AFB1 kg)1 diet showed impaired physiological responses and more AFB1 residue of muscles and ovaries above the safety limitation of European Union The authors are grateful Guanghan Nie for his technical help This study was supported by National Key Technology R&D Program (2007BAD37B02, 2001BA505B06) and partly by Natural Science Foundation of China (30700626) and Key Project of Hubei Provincial Science and Technology Department (2006AA203A01) Aebi, H (1984) Catalase in vitro Methods Enzymol., 105, 121126 Allameh, A., Safamehr, A., Mirhadi, S.A., Shivazad, M., RazzaghiAbyaneh, M & Afshar-Naderi, A (2005) Evaluation of biochemical and production parameters of broiler chicks fed ammonia treated aatoxin contaminated maize grains Anim Feed Sci Technol., 122, 289301 Amstad, P., Levy, A., Emerit, I & Cerutti, P (1984) Evidence for membrane-mediated chromosomal damage by AFB1 in human lymphocytes Carcinogenesis, 5, 719723 Belz, R.G., Cedergreen, N & Sứrensen, H (2008) Hormesis in mixtures Can it be predicted? 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335342 Aquaculture Nutrition 2010 16; 343350 1,2 doi: 10.1111/j.1365-2095.2009.00670.x Department of Fisheries Research Division, North Beach, WA, Australia; Present address, CSIRO Marine and Atmospheric Research, Cleveland, Queensland, Australia Several dietary strategies to ameliorate poorer growth observed to occur at temperatures above the upper thermal optima were examined with juvenile barramundi (Lates calcarifer) A reference (REF) and three experimental diets, one with an increased protein to energy ratio (PRO), another with an increased level of the amino acid histidine (HIS) and a third with supplementation of dietary nucleotides (NUC), were each fed to sh at either 30 C or 37 C for a 28-day period Growth was aected by both temperature and diet Fish fed the PRO diet at 30 C grew fastest, but not faster than those fed the NUC diet at the same temperature The addition of the amino acid histidine to the diet did not improve growth rates at either temperature At water temperatures of 37 C, only the sh fed the PRO diet had growth rates equivalent to those of sh at the 30 C temperatures Other key factors including feed intake, feed conversion rate, nutrient and energy retention and plasma enzymology were also all aected by temperature and diet This study shows that the use of a diet with an increased protein to energy ratio provides signicant benets in terms of reducing the impact of growth retardation at higher temperatures KEY WORDS: Asian seabass, heat, stress, temperature Received 26 September 2008, accepted March 2009 Correspondence: Brett Glencross, CSIRO Marine and Atmospheric Research, PO Box 120, Cleveland, QLD 4163, Australia E-mail: Brett Glencross@csiro.au Barramundi production in Australia occurs in water temperatures that range from [...]... 2009 Blackwell Publishing Ltd Aquaculture Nutrition 16; 343350 Li, P & Gatlin, D.M (2006) Nucleotide nutrition in sh: current knowledge and future applications Aquaculture, 251, 141152 Maynard, L.A & Loosli, J.K (1969) Animal Nutrition, 6th edn McGraw-Hill Book Co., New York, NY McMeniman, N (1998) Digestibility of feed ingredients in barramundi In: Fishmeal Replacement in Aquaculture Feeds for Barramundi... reared in cool water Aquacult Res., 37, 914927 ể 2009 The Authors Journal compilation ể 2009 Blackwell Publishing Ltd Aquaculture Nutrition 16; 343350 Aquaculture Nutrition 2010 16; 351358 1 1 1 1 doi: 10.1111/j.1365-2095.2009.00671.x 2,3 College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam; 2 Department of Fisheries Research Division, North Beach,... The Authors Journal compilation ể 2009 Blackwell Publishing Ltd Aquaculture Nutrition 16; 351358 This experiment was conducted in three settlement tanks Mass of faeces collected, ADC of DM, energy and nitrogen for the reference diet were calculated and compared with faeces collected by every 2 h after feeding (2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24 h) Fish were stocked 7 days prior to the start... calcarifer based on Australian production conditions Aquacult Nutr., 14, 360373 Helland, S., Grisdale-Helland, B & Nerland, S (1996) A simple method for the measurement of daily feed intake of groups of sh in tanks Aquaculture, 139, 156163 Katersky, R & Carter, C.G (2005) Growth eciency of juvenile barramundi, Lates calcarifer, at high temperatures Aquaculture, 250, 775780 Kopp, J., Loos, B., Spilker, G & Horch,... methods Aquaculture, 245, 211220 Glencross, B.D., Booth, M & Allan, G.L (2007) A feed is only as good as its ingredients a review of ingredient evaluation for aquaculture feeds Aquacult Nutr., 13, 1734 Hajen, W.E., Beames, R.M., Higgs, D.A & Dosanjh, B.S (1993) Digestibility of various feedstus by post-juvenile chinook salmon Oncorhynchus tshawytscha.in sea water: I Validation of technique Aquaculture, ... digesta collection Aquaculture, 77, 6170 Sugiura, S.H., Dong, F.M., Rathbone, C.K & Hardy, R.W (1998) Apparent protein digestibility and mineral availabilities in various feed ingredients for salmonid feeds Aquaculture, 159, 177 202 Sullivan, J.A & Reigh, R.C (1995) Apparent digestibility of selected feedstus in diets for hybrid striped bass (Morone saxatilis female x Morone chrysops male) Aquaculture, 138,... of common feed ingredients for channel catsh Prog Fish-Cult., 47, 154 ể 2009 The Authors Journal compilation ể 2009 Blackwell Publishing Ltd Aquaculture Nutrition 16; 351358 Aquaculture Nutrition doi: 10.1111/j.1365-2095.2009.00673.x 2010 16; 359369 1 2 3 1 1 1 1 3 1 Laboratorio de Enzimologia (LABENZ), Departamento de Bioqumica; Laboratorio de Imunopatologia Keizo Asami (LIKA),... Litopenaeus vannamei (Boone, 1931) Comp Biochem Physiol A, Mol Integr Physiol., 140, 2939 Guillaume, J (1997) Protein and amino acids In: Crustacean Nutrition, Advances in World Aquaculture (Abramo, L.R., Conklin, D.E & Akiyama, D.M eds), pp 2650 World Aquaculture Society, Baton Rouge Jiang, S.T., Moody, M & Chen, H.C (1991) Purication and characterization of proteases from digestive tract of grass... shrimp: digestive proteinases, proteinase inhibitors and feed digestibility Aquaculture, 186, 89105 Lemos, D., Garcia-Carreno, F.L., Hernandez, P & Navarrete Del Toro, A (2002) Ontogenetic variation in digestive proteinase activity, RNA and DNA content of larval and postlarval white shrimp Litopenaeus schmitti Aquaculture, 2 14, 363380 Lemos, D., Navarrete Del Toro, A., Cordova-Murueta, J.H & Garcia-Carreno,... Blackwell Publishing Ltd Aquaculture Nutrition 16; 359369 No claim to original US government works Asian bony tongue Scleropages formosus (Osteoglossidae) Aquaculture, 233, 305320 Nunes, A.J.P & Parsons, G.J (2000) Eects of the Southern brown shrimp, Penaeus subtilis, predation and articial feeding on the population dynamics of benthic polychaetes in tropical pond enclosures Aquaculture, 183, 125147