Dietary administration of chitooligosaccharides to enhance growth, innate immune response and disease resistance of Trachinotus ovatus

The present study was conducted to investigate the effects of dietary chitooligosaccharides (COS) supplementation on the innate immune response and protection against Vibrio harveyi infection in Trachinotus ovatus. A basal diet was supplemented with 0.0 (control), 2.0, 4.0 and 6.0 g COS kg^?1 to formulate four experimental diets. Each diet was randomly allocated to triplicate groups of ?sh in ?oating sea cages (1.5 × 1.0 × 2.0 m), and each cage was stocked with 80 ?sh (initial average weight 10.8 ± 0.05 g). After 8 weeks of feeding trial, Both the final weight and specific growth rate (SGR) signi?cantly increased with increasing dietary COS levels up to 4.0 g kg^?1, whereas there were no signi?cant differences for COS levels from 4.0 to 6.0 g kg^?1. A decreased feed conversion ratio (FCR) was observed with increasing dietary COS levels. The total leukocyte counts (WBC), differential leukocyte counts, respiratory burst activity, lysozyme and superoxide dismutase (SOD) activity were signi?cantly increased with the increased levels of dietary COS (P < 0.05), and reached a maximum at level of 4.0 g kg^?1 COS. There were no signi?cant differences in those immunological parameters between 4.0 and 6.0 g kg^?1 COS. Moreover, the dietary COS supplementation groups also exhibited a decrease in the cumulative symptom rates compared to the controls when challenged with V. harveyi. These results indicated that dietary intake containing COS could enhance the immune responses of fish and improve its resistance to infection by V. harveyi. Especially supplementation with 4.0 g kg^?1 COS to the fish for 56 days showed considerable improvement in the growth, survival and immune response of the fish.     

Growth,parasitic infection and hematology in Colossoma macropomum Cuvier, 1818 fed diets containing Allium sativum

The aim of this study was to investigate the effects of a dietary Allium sativum (garlic) addition on growth, parasite infestation and blood parameters in Colossoma macropomum (tambaqui) using 12 net‐cages (1 m³). There were four treatments with three replicates each (15 fish per replicate). Tambaqui of 112.4 g mean weight were fed for 45 days with diets containing 0, 15, 30 and 45 g of fresh garlic kg^?1 feed. Garlic did not affect the tambaqui survival, growth, feed conversion, body condition, plasma glucose levels, total plasma protein levels or red blood cells. Total leukocyte and lymphocyte numbers decreased in fish fed diets containing 45 g garlic kg^?1 feed, but neutrophils decreased in fish fed diets containing 15, 30 and 45 g garlic kg^?1 diet, while the number of immature leukocytes increased in fish fed 30 g and 45 g garlic kg^?1diet. Gills in fish fed 30 and 45 g kg^?1 diet had lower infestation (52% and 63%, respectively) of Anacanthorus spathulatus (Monogenea) compared to controls. The application of garlic in diets improved the response of leukocytes and enhanced the resistance to infections by monogeneans.     

Effect of dietary dextrin levels on the growth performance,blood chemistry,body composition,hepatic triglicerides and glycogen of Lebranche mullet juveniles (Mugil liza Valenciennes 1836, Mugilidae)

The effects of increasing levels of dietary dextrin on growth performance, body composition, blood chemistry and hepatic triglycerides and glycogen levels were evaluated for juvenile Lebranche mullet, Mugil liza Valenciennes 1836, Mugilidae). Five diets were formulated to be isonitrogenous (350 g kg^?1) and isolipidic (6 g kg^?1) with increasing dextrin levels (D150: 150 g kg^?1; D200: 200 g kg^?1; D250: 250 g kg^?1; D300: 300 g kg^?1; D350: 350 g kg^?1). The experimental diets were offered to the fish for 34 days, four times per day, until apparent satiation. Each treatment was tested in triplicate, with nine fish per tank (mean weight 4.69 ± 0.31 g). Fish were reared in a recirculating aquatic system of 15 fibreglass tanks each containing 50 L of saltwater. Growth parameters and body composition of the mullets were not significantly affected (P > 0.05) by the dietary treatments. Plasma glucose concentration declined (P < 0.05) when dietary dextrin increased from D250 to D300, but recovered to the previous values (in reference to D150 and D200) when fish were fed with D350. Glycated haemoglobin, plasma proteins, triglycerides and cholesterol showed no significant differences among these treatments. Hepatic glycogen reached a maximum in treatment D250, followed by D350, D200 and D300, with the lowest concentration of liver glycogen found in D150 (P < 0.05). The concentration of liver triglycerides showed an increase (P < 0.05) in treatments D300 and D350 compared with D200. In conclusion, Mugil liza juveniles can be fed diets with high levels of dietary dextrin with no deleterious effects to their growth or plasma biochemistry, hepatic glycogen or triglycerides.     

Effects of β‐xylanase and 6‐phytase on digestibility,trace mineral utilisation and growth in juvenile red tilapia,Oreochromis niloticus (Linnaeus, 1758) x O. mossambicus (Peters, 1852), fed declining fishmeal diets

In response to the global sustainability drive to lower fishmeal (FM) inclusion in aquatic feeds, exogenous enzymes can improve nutrient digestibility in monogastric plant‐based diets. A 80‐day experiment was conducted to evaluate the combined effects of xylanase and phytase on digestibility, trace mineral utilisation and growth in juvenile red tilapia, Oreochromis niloticus x O. mossambicus, (48.8 g ± 13.9; μ ± STD) fed declining FM diets. Basal diets were formulated to contain 0, 3 and 5% FM with and without xylanase (0.385 g kg^?1) and phytase (0.075 g kg^?1), forming six treatments. Each treatment was randomly assigned to four replicates, 20 fish tank^?1; mean water temperature 28.98 ± 0.73°C. Although the size of the effects was modest, growth performances (feed intake, FCR, growth rate) decreased with lower FM levels (P < 0.05) but improved with enzyme supplementation. Enzyme supplementation increased P digestibility and trace mineral uptake (P < 0.05), but no effects were seen on protein digestibility and N retention. Nevertheless, tilapia fed the enzyme‐supplemented 3% FM and control 5% FM diets performed comparably (P < 0.05). This potentially justifies a 2% FM reduction for tilapia diets using exogenous xylanase and phytase without significant effects on digestibility, trace mineral utilisation and growth.     

Immunomodulatory effect of sodium alginate enriched diet in kelp grouper Epinephelus brneus against Streptococcus iniae

The effect of diets containing sodium alginate at 0, 0.5, 1.0, and 2.0 g kg^?1 following challenge with Streptococcus iniae in kelp grouper Epinephelus bruneus were assessed with reference to survival rate and innate immune parameters such as alternative complement, lysozyme, natural haemagglutination, respiratory burst, superoxide dismutase, and phagocytic activities on week 1, 2, and 4. Fish fed with sodium alginate containing diet at 1.0 and 2.0 g kg^?1 after being challenged with S. iniae had higher survival rates of 75% and 60%, respectively than those fed with control diet (0 g kg^?1). With any enriched diet the percentage of macrophages significantly decreased from week 1–4, while the percentage of neutrophils and lymphocytes significantly increased. The alternate complement activity, natural haemagglutination, and phagocytic activities of infected fish fed with sodium alginate containing diet at 1.0 g kg^?1 on week 2 and 1.0 and 2.0 g kg^?1 diets on week 4 were significantly higher when compared to the control. The lysozyme, respiratory bursts, and superoxide dismutase activities of fish fed with enriched diets at 1.0 and 2.0 g kg^?1 were significantly increased on week 2 and 4. We therefore recommend that at 1.0 or 2.0 g kg^?1 dietary administration of sodium alginate can enhance innate immunity and disease resistance in kelp grouper against S. iniae.     

Partial replacement of monocalcium phosphate with neutral phytase in diets for grass carp,Ctenopharyngodon idellus

A 9‐week experiment was designed to study the effects of partial replacement of monocalcium phosphate (MCP) with neutral phytase on growth, body compositions, serum biochemical statuses and intestinal digestive enzyme activities of grass carp, Ctenopharyngodon idellus. The control diet (designated as P2.0) was prepared with 2.0% MCP but without phytase. The three other diets (designated as PP1.5, PP1.0 and PP0.5, respectively) were supplemented with 1.5, 1.0 and 0.5% MCP, respectively, along with 500 FTU of neutral phytase kg^?1 diet in each. After a 9‐week feeding trial, fish (initial body weight: 43.44 ± 2.37 g) fed with PP1.5 and PP1.0 had no significant change in weight gain (WG), specific growth rate (SGR), protein efficiency rate (PER) or feed conversion ratio (FCR) compared with the control (P > 0.05) whereas fish fed with PP0.5 showed significantly lower growth performance in the above parameters. The crude lipid content in whole body or muscle of the fish fed with PP1.5 was significantly lower than the control while significantly higher in fish fed with PP0.5 (P < 0.05), whereas no obvious change was observed in the fish fed with PP1.0. For serum indices, higher serum alkaline phosphatase (Alkp), phosphorus (P) and calcium (Ca) contents were observed in fish fed with phytase‐supplemented diets in comparison with the control. In addition, dietary phytase supplementation increased amylase activity and decreased lipase activity in both foregut and hindgut. The present study suggests that dietary MCP can be reduced when neutral phytase is added to the grass carp diet, and that the maximum MCP reduction level can be up to 1% when neutral phytase is supplemented at 500 FTU kg^?1 diet.     

Coriolus versicolor polysaccharides enhance the immune response of crucian carp (Corassius auratus gibelio) and protect against Aeromonas hydrophila

To investigate the effect of Coriolus versicolor polysaccharides (CVPS) on the immune response of crucian carp (Corassius auratus gibelio), fish were fed diets containing CVPS at different concentrations including 0.5, 1.0 and 2.0 g kg^?1 for 5 weeks. Other groups of fish were vaccinated by intraperitoneal injection (i.p.) against Aeromonas hydrophila with a killed bacterin at the beginning of the experiment and fed the same diets as described above. Additionally, control fish and vaccinated‐only fish were fed basal diets without CVPS supplementation. The phagocytosis, lysozyme activity, complement components C3 and C4, E‐C3bRR (Erythrocyte‐C3b rosette rate) and E‐CIRR (Erythrocyte‐immune complex rosette rate) levels and circulating antibody titers in the serum were monitored. Five weeks after feeding the prescribed diet, fish were challenged with A. hydrophila and the mortalities recorded. Results showed that feeding non‐vaccinated and vaccinated crucian carp with CVPS stimulated the phagocytosis of leukocytes, lysozyme, complement components C3 and C4, erythrocyte immune adherence, and circulatory antibody titers in serum in vaccinated crucian carp. Immune parameters increased to their highest levels after 3 weeks of feeding the diet containing 0.5 or 1.0 g kg^?1 CVPS. These doses also resulted in the highest protection in the challenge experiment. Best survival (85%) was in the vaccinated group fed the diet containing 1.0 g kg^?1 CVPS, whereas almost 80% of control fish (negative control) and 50% of vaccinated‐only fish (positive control) died.     

Effects of varying levels of dietary vitamin E (α‐tocopherol) on growth performance,proximate and fatty acid composition of juvenile silver pomfret (Pampus argenteus Euphrasen, 1788)

This study investigated the effects of elevated dietary levels of vitamin E (α‐tocopherol) on growth performance, proximate composition and fatty acid profiles of juvenile silver pomfret, Pampus argenteus. Three semi‐purified experimental diets were formulated to contain 49% protein and 16% lipid. High docosahexaenoic acid (DHA) tuna oil was added to the diets to supplement DHA. A graded level of vitamin E (0‐, 50‐, and 100 mg kg^?1) was added to experimental diets 1 to 3, respectively. Analyzed vit. E levels were 155.2, 195.3 and 236.4 mg kg^?1 in diets 1, 2 and 3, respectively. The experiment was conducted for 12 weeks with juvenile silver pomfret (29.6 ± 7.6 g) using a flow‐through system consisting of nine 1‐m³ tanks. Each treatment had three replicates and fish were stocked at the rate of 20 m^?3. Growth performance and feed utilization parameters of fish fed diets 2 and 3 were significantly (P < 0.05) higher than in fish fed diet 1, but the parameters in diets 2 and 3 did not differ significantly (P > 0.05). Although whole body protein levels were not influenced by the dietary vit. E levels, whole body lipid in fish fed diet 2 was significantly higher than in fish fed the other diets. The whole body vit. E levels in fish fed diet 2 (22.6 mg kg^?1) and diet 3 (24.1 mg kg^?1) were significantly (P < 0.05) higher than in those fed diet 1 (18.2 mg kg^?1). Whole body total saturated fatty acids were significantly lower, and DHA levels higher in fish fed diets 2 and 3 than those fed diet 1. The results of the present study suggest that increasing dietary supplementation of vit. E in high lipid diets enhances the growth performance of fish and that a dietary level of 196 mg kg^?1 vit. E is suitable for the growth of silver pomfret.     

Effect of prebiotic mannan oligosaccharide on hematological and blood serum biochemical parameters of cultured juvenile great sturgeon (Huso huso Linnaeus, 1754)

The nutritional effects of prebiotic mannan oligosaccharide were evaluated using hematological and blood serum biochemical parameters in cultured juvenile great sturgeon (Huso huso). Fish were offered formulated diets containing two levels of prebiotic mannan oligosaccharide (2 and 4 g kg^?1); a basal diet with no prebiotics was used as control. The experiment lasted for 46 days. Blood samples were collected from the caudal veins of 18 apparently healthy fish (average weight 217.77 ± 29.8 g) at the end of the trial. No significant differences were found in the serum enzyme activity levels between treatments (P > 0.05). However, adding mannan oligosaccharide as a supplement to the basal diet resulted in significant differences in lymphocytes and eosinophils between the control and the 2 g kg^?1 treatment (P < 0.05) as well as a significant difference in the creatinine factor in the 2 g kg^?1 mannan oligosaccharide treatment (P < 0.05). The results show that it would be advantageous to add 2 g kg^?1 mannan oligosaccharide to the diets of juvenile great beluga sturgeon (Huso huso).     

Preliminary results on growth and feeding of wild-caught young goldblotch grouper, Epinephelus costae, in captivity

Growth, food intake, feed conversion, survival, and behaviour of wild‐caught goldblotch grouper, Epinephelus costae Steindachner, (initial weight=103.04 ± 8.27g) were evaluated when reared in captivity. Average weight gains ranged between 0.106 and 0.278 g day^?1, while corresponding gains in length ranged between 0.005 and 0.018 cm day^?1. Average daily growth rate was between 0.075 and 0.232% body weight day^?1 (overall 0.141 ± 0.08% bw/day). Daily rate of feeding was estimated to be between 0.299 and 0.418% bw day^?1 (overall 0.365 ± 0.09% bw day^?1). Food conversion ratio (FCR) ranged between 0.21 and 0.77 (overall FCR=0.423). Food intake was dependent on water temperature.     

Growth Performance,Hemato-Immunological Responses,and Digestive Enzyme Activities in Silvery-Black Porgy (<Emphasis Type="Italic">Sparidentex hasta</Emphasis>) Fed Dietary Bovine Lactoferrin

An 8-week study was conducted to evaluate three different diets supplemented with bovine lactoferrin (LF) at 0 (control), 800, and 1200 mg LF kg^?1 diet on somatic growth, hemato-immunological parameters, antioxidant status, and digestive enzyme activities in silvery-black porgy (Sparidentex hasta) juveniles. Fish fed the 800 mg LF kg^?1 diet had higher growth performance and feed utilization parameters than the other groups. Hematological and liver antioxidant parameters were not affected by dietary LF supplementation. Fish fed the 800 mg LF kg^?1 diet had higher plasma lysozyme activity values than the other groups. Total protease activity was higher in fish fed LF-supplemented diets than the control group. Results indicated that diet supplemented with 800 mg kg^?1 for 8 weeks enhanced somatic growth performance, lysozyme activity, and proteolytic digestive enzyme activities in S. hasta, as well as improving feed efficiency parameters like the protein efficiency and feed conversion ratios.     

Pharmacokinetics of oxytetracycline in yellow catfish [Pelteobagrus fulvidraco (Richardson, 1846)] with a single and multiple‐dose oral administration

A pharmacokinetic study of oxytetracycline (OTC) following a single (100 mg kg^?1) or a multi‐dose (100 mg kg^?1 for 5 days) oral administration was carried out in yellow catfish, Pelteobagrus fulvidraco. After oral administration at 25°C, a one‐compartment model was developed. The absorption half‐life (t_1/2(ka)) was 3.92, 1.44, 2.75, and 3.34 h in plasma, muscle, liver, and kidney after the single dose, and 0.35, 0.22, 0.42, 0.32 h after the multi‐dose, respectively. The order of peak concentration (C_max) was liver > kidney > plasma > muscle, at 3.48 μg g^?1, 2.90 μg g^?1, 1.46 μg ml^?1, and 1.39 μg g^?1 after the single dose, and 14.02 μg g^?1, 8.51 μg g^?1, 4.17 μg ml^?1, and 3.84 μg g^?1 after the multi‐dose, respectively. The elimination half‐lives (t_1/2(ke)) of OTC in plasma, muscle, liver, and kidney were calculated to be 7.64, 26.29, 19.08, and 10.61 h after the single dose, and 47.54, 70.99, 49.87, and 47.73 h after the multi‐dose, respectively. The results suggest that OTC was absorbed faster after the multi‐dose than after the single dose, suggesting that OTC could be more efficacious after the multi‐dose and more effective in the control bacterial diseases in aquaculture, with the side effects of longer withdrawal periods.     

Effects of different protein and carbohydrate levels on growth performance and feed utilisation of brook trout,Salvelinus fontinalis (Mitchill, 1814), at two temperatures

A 12‐week feeding trial was conducted to determine the optimum dietary protein requirement of brook trout, Salvelinus fontinalis, at 15 and 19°C. Twelve iso‐energetic (22 MJ · kg^?1) and iso‐lipidic (23%) diets (36–58% protein at 2% increments) were prepared. Fish (29.45 ± 3.25 g · fish^?1) were fed 2% of body weight per day, divided into two equal rations. The specific growth rate (SGR, % · day^?1), feed efficiency ratio (FER), productive protein value (PPV), productive lipid value (PLV) and productive energy value (PEV), apparent digestibility of diet (AD_DM) and protein (AD_CP) were significantly higher at optimum temperature (15°C). Increasing PPV with increasing dietary carbohydrate and with decreasing dietary protein content was due to the protein‐sparing effect of carbohydrates. A piecewise regression (broken line) model between the SGR and digestible dietary protein level revealed that the digestible dietary protein requirement of brook trout was 44 and 40% at 15 and 19°C, respectively. When PPV (digestible protein retention basis) was modelled with a broken line, the digestible protein requirement of brook trout was 39 and 35% at 15 and 19°C, respectively. A reduction in dietary protein content balanced by increased gelatinised carbohydrate might be useful for improving the protein utilization efficiency for growth at 15 and 19°C; however, the growth and feed efficiency was lower at the elevated temperature.     

Growth,biochemical, fatty acid composition,and mRNA levels of hepatic enzymes in genetically improved farmed tilapia (GIFT,Oreochromis niloticus) (Linnaeus, 1758) at different stocking densities

Investigated were the effects of stocking density on juvenile growth performance, serum biochemistry, fatty acid composition, and mRNA levels of enzymes involved in lipid metabolism in genetically improved farmed tilapia (GIFT), Oreochromis niloticus. Juvenile fish (n = 900) were distributed into 15 tanks at five initial stocking densities (75, 150, 225, 300, and 375 g/m³ per 800‐L tank, represented as D1–D5, respectively). Temperature was maintained at 28 ± 0.3°C, and water flow rate into the tanks was about 8 L/min. The fish accepted floating pelleted feed (crude protein 28%, crude lipid 6%, and gross energy 149.2 KJ/g diet). The feed amount offered was 4%–8% of body weight. At the end of the 60‐day experiment, the final stocking densities were 1,454.18, 2,010.60, 2,913.13, 3,819.73, and 4,380.80 g/m³, respectively. Growth and body mass coefficient of variation were significantly affected (p < .05). No differences in feed conversion rate or survival were found (p > .05). Muscle lipid contents decreased with stocking density from D1 to D5. Serum total protein and cholesterol levels were not affected by the stocking density but the D5 group produced the highest serum cortisol and lactate levels and the lowest glucose levels compared to those of the other groups. Lower muscle saturated fatty acid and n?3 polyunsaturated fatty acid contents were observed in the D4 group than in the other groups, whereas the reverse was found in the n?6 polyunsaturated fatty acid content. Hepatic glucose 6‐phosphate dehydrogenase, fatty acid synthetase, hormone‐sensitive triglyceride lipase, and lipoprotein lipase mRNA levels were significantly upregulated in response to a high density. These data suggest that the GIFT adapted to high‐density conditions by altering the composition of muscle fatty acid and stimulating lipid metabolic enzymes. These mechanisms may help fish respond to high stocking density stress in intensive aquaculture systems.     

Effects of the Cry1Ac toxin of Bacillus thuringiensis on Microplitis mediator, a parasitoid of the cotton bollworm, Helicoverpa armigera

Interactions between the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), its larval parasitoid Microplitis mediator (Haliday) (Hymenoptera: Braconidae), and the Cry1Ac toxin of Bacillus thuringiensis Berliner were evaluated under laboratory conditions. The growth of H. armigera larvae was delayed and its pupal rate and pupal weight decreased when they were fed on a diet containing Cry1Ac toxin. Due to the lowered growth rate of the host larvae, the time available for parasitization of H. armigera by M. mediator increased when the host larvae were reared on a diet containing Cry1Ac toxin at concentrations of 0.5, 1, 2, and 4 µg g^?1. The longevity of female and male parasitoids was not significantly affected when newly emerging wasps fed on honey solutions containing three different concentrations of Cry1Ac toxin (125, 250, and 500 µg ml^?1). When female parasitoids were fed on honey solutions containing Cry1Ac, their offsprings’ egg and larval development period, pupal weight, length of pupation, adult weight, and adult longevity did not change significantly in most of the treatments compared with controls. When the female parasitoids parasitized host larvae that had been fed on a diet containing 0.5, 1, 2, 4, and 8 µg g^?1 Cry1Ac toxin, their offsprings’ eggs and larvae were significantly delayed. Their pupal weight, adult weight, and adult longevity were also significantly less than controls.     

Effects of dietary l‐carnitine supplements on growth and body composition in beluga sturgeon (Huso huso) juveniles

The effects of dietary l ‐carnitine on growth performance, whole body composition and feed utilization were studied in beluga, Huso huso. Fish were randomly allocated in 15 tanks (30 fish per tank) and triplicate groups were fed to satiety during 84 days one of five isonitrogenous (41% CP) and isoenergetic (20 MJ kg^?1) diets, each differing in l ‐carnitine content [0 (control), 300, 600, 900 and 1200 mg kg^?1 diet]. At the end of the trial, fish grew from 19‐ to 23‐fold in weight, from 8.4 g to a maximum of 191 g. Fish fed 300–600 mg l ‐carnitine had the highest specific growth rate (SGR, 3.69 and 3.72% day^?1) and protein efficiency ratio (PER, 0.95 and 0.99), and the lowest feed conversion ratio (FCR, 1.4 and 1.3) than the other groups (P < 0.0001). SGR, PER and FCR were the poorest for fish fed 1200 mg l ‐carnitine, while fish fed the unsupplemented and 900 mg l ‐carnitine supplemented diet showed intermediate performance. Body lipid concentration decreased significantly from 5.8 to 5.1% (P < 0.0001) with dietary l ‐carnitine supplementation increasing from 0 to 300 mg. Energy content was significantly lower in fish fed the 900 and 1200 mg l ‐carnitine diet (5.8 MJ kg^?1), when compared with the other treatment groups (6.4–6.6 MJ kg^?1). The results indicated that feeding sturgeon on diets supplemented with 300 mg l ‐carnitine kg^?1 diet improved growth performance, and stimulated protein‐sparing effects from lipids.     

Hematology and plasma chemistry of wild shortnose sturgeon Acipenser brevirostrum from Delaware River,USA

The effects of gender, maturity, intersex condition and annual and seasonal variability were studied on hematology and plasma chemistry of wild shortnose sturgeon Acipenser brevirostrum from the Delaware River. A total of 68 fish were captured by gill net and examined in May‐June, and 61 additional fish were captured and examined in November during 2006–2011. Total leukocyte counts (WBC), leukogram, PCV and the plasmatic concentrations of 13 biochemical analytes were measured from these fish using standard clinical methods. Season and gender had no effect on hematologic indices, but PCV was inversely related to maturity of fish (robust intervals: 27–40% in immature fish, 21–36% in mature fish). Significant annual variation was detected in eosinophil (annual range in robust interval: 0–1176 lower limit, 670–7882 upper limit) and monocyte (0–210 lower limit, 560–1980 upper limit) counts (cells μl^?1). The lower limit of the robust interval varied annually by as much as 6% for sodium and 12% for chloride, while the upper limit of the robust interval varied annually by as much as 8% for sodium and 15% for chloride. Seasonal differences in mean sodium and chloride (6–7% higher in autumn) and proteins (5–13% higher in autumn) may reflect environmentally induced changes in osmoregulation, while aspartate aminotransferase was 38–55% higher in the spring. In females, calcium and total protein were highest in mature fish (robust intervals: 10.5–22.1 mg dl^?1 Ca²⁺, 4.1–6.9 g dl^?1 TP) compared to immature (7.3–16.9 mg dl^?1 Ca²⁺, 2.8–5.2 g dl^?1 TP) and developing fish (7.8–18.9 mg dl^?1 Ca²⁺, 3.2–5.6 g dl^?1 TP), indicating changes associated with vitellogenesis. Glucose was significantly higher in females (robust interval: 23–167 mg dl^?1) than males (35–138 mg dl^?1), possibly indicating gender‐based differences in energetic requirements. Intersex condition was associated with lowered glucose, potassium and creatinine phosphokinase. Reference intervals reported here are useful for evaluating the health and physiological condition of shortnose sturgeon.     

Organochlorine pesticides in Muraena helena L. 1758 from the Eastern Adriatic Sea

This work examines the bioaccumulated organochlorine compounds in Muraena helena to draw attention to this species as a potential bioindicator organism. The morays were caught in the East Adriatic Sea, Elaphite Islands, near Dubrovnik, Croatia (lat: 42°45′38.8″; long: 17°45′53.6″) at the same location in summer (August, 2009) and winter (January, 2010), at depths from 5 to 10 m. Nine fish were caught by longline hooks per each field trip (total in summer and winter, N = 18). No single fish was free of organochlorines (OC), but not all pesticides were present in every fish. The concentration level was: Endrin > ppDDE > Heptachlor epoxide > Heptachlor > Aldrine > Lindane > βHCH > δHCH > Endrin aldehyde). Endrin was the only pesticide approaching the maximum concentrations proposed by the European Union and Croatia (summer max. concentration = 14.75 μg kg^?1; winter max. concentration = 8.35 μg kg^?1). All other pesticides ranged from 0.1 to 0.7 μg kg^?1. Heptachlor was absent in winter and δ‐HCH and Endrin aldehyde in summer, while Lindane and pp‐DDE had higher (P ≤ 0.05) concentrations in summer. Other residues had similar seasonal concentration levels. The p‐DDT was similar as in other biota from the Adriatic or Mediterranean. HCH concentrations corresponded to those found in organisms from the Italian area of the Adriatic. The endocrine and reproductive disrupting potential of the detected OCs are bases for future studies. Results show that morays are a good bioindicator model, with slight interspecies and seasonal variability in OC bioaccumulation as a consequence of diverse food consumption.     

Effect of different levels of phytase on growth and mineral deposition in common carp (Cyprinus carpio,L.)

The effect of phytase (Ronozyme P) on growth and mineral deposition in common carp (Cyprinus carpio L) was evaluated. Five diets (treatments T1‐T5) were prepared to contain about 36.6% DM proteins and 0.55% DM phosphorus. Diet 1 had no supplement; diet 2 was supplemented with 2.80 g inorganic phosphorus (P) (Na₂HPO₄) kg^?1. Diets 3, 4 and 5 were supplemented with 500, 750 and 1000 U phytase kg^?1. After 126‐day feeding trials, fish grew from 39.9 g to 158 g, 262 g, 155 g, 166 g and 172 g in diets T1‐T5, respectively. There were no differences (P > 0.05) in mean weight gain, SGR, feed intake or feed conversion ratio of fish in T1, T3, T4 and T5. T2 fish had the best (P < 0.05) growth performance. Apparent P digestibility was significantly higher in T2, while faecal P discharges were significantly reduced in T3, T4 and T5. Fish in T2, T3 and T4 had higher (P < 0.05) bone P than that in T1. Vertebral Mg (mg g^?1 DM) of fish in T3, T4 and T5 were higher (P < 0.05) than that of fish in T1. Bone Mn showed the same trend. Data indicated that the enzyme exhibited no clear improvement for a higher P availability.     

Liver alteration and hematological and serum biochemical responses of common carp,Cyprinus carpio Linnaeus, 1758, following long‐term feeding of pistachio (Pistacia vera) green hull extract as a source of natural phenol

This study was conducted to investigate the effect of pistachio green hull extract (PGHE) on hematological and serum biochemical changes in common carp, Cyprinus carpio. Three hundred common carp (11.65 ± 1.65 g) were fed one of five different dietary treatments (with three replications) containing 0, 0.5, 1.5, 4.5 or 9 g PGHE kg^?1diet for ten continuous weeks. Each tank had a 90‐L capacity and water flow rate of about 500 ml min^_1.Total phenolic compounds of the different diets differed significantly (P < 0.001) according to the amount of PGHE. At the end of experiment, six fish were removed randomly from each treatment. Blood samples were taken for hematological and serum biochemical analyses at room temperature. Liver tissue samples were processed for histology and stained by H&E. The results indicated that all doses of tested PGHE induced no significant changes in hematocrit, hemoglobin, or erythrocytes, nor alkaline phosphatase, alanine transaminase, lactate dehydrogenase, total protein, albumin, globulin, triglycerides, low‐density lipoprotein, high‐density lipoprotein, glucose or cholesterol in the serum. Leukocytes were higher (P < 0.01) in fish fed a 1.5, 4.5, or 9 g PGHE kg^?1 diet when compared to the 0.5 g PGHE kg^?1 diet group or the control. Serum aspartate transaminase in treatments containing a 4.5 or 9 g PGHE kg^?1 diet was significantly (P < 0.001) higher in comparison with the control. Liver histology showed focal necrosis, cytoplasm degeneration, lateral nuclei and an increase in Kupffer cells following PGHE administrations. The results of this trial indicated that although there were no significant changes in most hematological and biochemical parameters, PGHE could induce some adverse pathological effects on liver tissue.