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The present study was conducted to evaluate dietary inosine 5'-monophosphate (5'-IMP) on growth, immune genes expression and disease resistance against Aeromonas hydrophila in juvenile gibel carp (Carassius auratus gibelio var. CAS Ⅲ) (initial body weight: 7.48 g). Six diets were formulated containing exogenous 5'-IMP at three gradient levels (0, 0.1% and 0.2%) in the high dietary fishmeal group (15% fishmeal: D1, D2, D3) and in the high dietary soybean meal group (33% soybean meal: D4, D5, D6). Each diet was randomly allotted to triplicate tanks in a recirculating system. After the feeding trial, fish were exposed to Aeromonas hydrophila challenge. Hematological and immunological responses were analyzed before and after challenge. The results indicated that feeding rate in all 5'-IMP supplemented treatments (D2, D3, D5 and D6) and daily growth coefficient in D5 and D6 were reduced compared with those of respective control treatments (D1 and D4) without 5'-IMP addition (P < 0.05). The cumulative survival rates were numerically improved by dietary 5'-IMP supplementation (P > 0.05). Compared with the respective control treatment, in the high fishmeal group, plasma SOD and MPO were significantly elevated in D3 at the end of feeding trial (P < 0.05), plasma SOD and lysozyme were significantly increased in D3 after bacterial challenge (P < 0.05); in high soybean meal group, plasma lysozyme activity was significantly elevated in D5 post bacterial challenge (P < 0.05). Most of the expression of immune related genes (intelectin, major histocompatibility complex class II β (MHC II β), Complement 3 (C3), Complement component C7-1 (ccC7), lysozyme C, Interleukin 1β (IL-1β), Tumor necrosis factor α1 (TNF-α1), Transforming growth factor-beta (TGF-β) and Interleukin 8 (IL-8)) in spleen, kidney and liver of the fish were significantly affected by supplementation of 5'-IMP at the end of feeding trial and post bacterial challenge. Additionally, adding 5'-IMP in high soybean meal diets exerted further effects of promoting immunity than counterparts in high fishmeal diets. Considering enhanced disease resistance, the immunopotentiation of 5'-IMP was manifested when the addition level was 0.1% in high soybean meal diets and 0.2% in high fishmeal diets., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

A 50-day feeding trial was carried out to evaluate the partial replacement of fishmeal by yeast culture (YC) on growth performance, immune response and resistance against Aeromonas hydrophila in gibel carp CAS Ⅲ (Carassius auratus gibelio). Four isonitrogenous and isoenergetic practical diets including a basal diet (the control diet containing 10% fish meal, D0) and three yeast culture diets (substituting 20%, 40%, 60% of the fishmeal in the basal diet, D20, D40 and D60, respectively) were formulated. Each diet was randomly allocated to quadruplicate fish groups (average initial body weight: 28.70 ± 0.03 g) reared in a recirculating system. After the growth trial, bacterial challenge test was conducted. The results showed that no noteworthy variations in feed intake, growth performance and morphology indices were found among groups (P > 0.05). YC Supplemented diet exerted little significant influence on plasma parameters including triglyceride, glucose, creatinine, total protein and urea nitrogen compared with the control group (P > 0.05). No obvious variations were found in activities of plasma lysozyme, IgM, MPO and SOD before challenge test among dietary treatments (P > 0.05), whereas considerable higher value of the foresaid indicators was discovered in D40 after bacteria challenge (P < 0.05). Transcriptional levels of Toll like receptor 2 (TLR2), myeloid differentiation factor 88 (MyD88), Toll/IL-1 receptor domain-containing adaptor protein (TIRAP) and interleukin-1β (IL-1β) in spleen after challenge were significantly up-regulated in D40 compared with D0 (P < 0.05). Cumulative survival rate in D40 and D60 were significantly higher than those in D0 and D20 (P < 0.05). Taken together, yeast culture could be a suitable fishmeal alternative in diets of gibel carp and dietary inclusion of 4 g YC per 100 g diet enhanced the immunity and disease resistance of gibel carp partly via TLR2 pathway., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The present study examined the effect of dietary spirulina, Arthrospira platensis on growth performance, blood physiological indices, immune-related gene expressions and resistance of juvenile gibel carp against Aeromonas hydrophila infection. Four isonitrogenous (360 g kg -1 ) and isolipidic (90 g kg -1 ) diets were formulated with containing different levels of spirulina powder of 0 g (SP0, the control diet), 3.38 g (SP3.38), 6.76 g (SP6.76) and 13.52 g (SP13.52) per 100 g diet to replace 0%, 25%, 50% and 100% of fishmeal protein, respectively. And each diet was randomly assigned to triplicate tanks (150-L capacity per each) and each tank was stocked with 22 fish (15.37 ± 0.06 g). Fish were fed one of the tested diets up to satiation twice a day for 46 days. A challenge test was carried out after the feeding trial by injecting Aeromonas hydrophila intraperitoneally for 7 days. The results showed that fish growth, feeding rate in groups SP3.38 and SP6.76 were significantly higher than those of groups SP0 and SP13.52 (P < 0.05). Feed efficiency and protein retention rate had no significant difference among all tested groups. Plasma superoxide dismutase and phagocyte activity of blood leukocytes significantly increased in the spirulina-fed fish groups at 12-h post the bacterial challenge (P < 0.05). Both pre and post challenge test, plasma lysozyme activities in spirulina-fed groups were significantly higher than that in the control group (P < 0.05). Plasma malondialdehyde got the lowest value in the SP13.52 group before and after the challenge test. The transcriptional levels of TLR2 (Toll like receptor 2), myeloid differentiation factor 88 (MyD88), Toll/IL-1 receptor domain-containing adaptor protein (TIRAP), interleukin-1β (IL-1β) and tumor necrosis factor-α1 (TNF-α1) in spleen and kidney significantly increased post the bacterial challenge compared to the pre challenge. And the relative expressions of the immune-related genes of spirulina-fed fish groups were higher than those of the control group before and after the challenge test. The 7-day cumulative survival rate after the bacterial challenge was highest in the SP3.38 group (P < 0.05). The present results indicated that low dietary inclusion of spirulina significantly enhanced the immune response of gibel carp partly through TLR2 pathway and 3.38% of dietary spirulina was recommended for the juveniles based on the growth and immune response., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

QTL is a chromosomal region including single gene or gene clusters that determine a quantitative trait. While feed efficiency is highly important in aquaculture fish, little genetic and genomic progresses have been made for this trait. In this study, we constructed a high-resolution genetic linkage map in a full-sib F1 family of crucian carp (Carassius auratus) consisting of 113 progenies with 8,460 SNP markers assigning onto 50 linkage groups (LGs). This genetic map spanned 4,047.824 cM (0.478 cM/marker) and covered 98.76% of the crucian carp genome. 35 chromosome-wide QTL affecting feed conversion efficiency (FCE, 8 QTL), relative growth rate (RGR, 9 QTL), average daily gain (ADG, 13 QTL) and average daily feed intake (ADFI, 5 QTL) were detected on 14 LGs, explaining 14.0-20.9% of the phenotypic variations. In LGs of LG16, LG25, LG36 and LG49, several QTL affecting different traits clustered together at the identical or close regions of the same linkage group. Seven candidate genes, whose biological functions may involve in the energy metabolism, digestion, biosynthesis and signal transduction, were identified from these QTL intervals by comparative genomics analysis. These results provide a basis for elucidating genetic mechanism of feed efficiency and potential marker-assisted selection in crucian carp.

High mortalities and suppressed immune functions of farmed fish over winter are the universal problems in aquaculture. It is necessary to improve the immune response and disease resistance in the overwintering fish. A recent study suggested that repeated handling increased innate immune mechanisms and disease resistance in Senegalese sole. Therefore, the present study evaluated the hypothesis that appropriate repeated handling could compromise the immune depression and increase the disease resistance in gibel carp over winter. The experiment was executed in field net cages (2 m × 2 m × 2 m) from Dec. 4, 2012 to Apr. 2, 2013. Three cages with 50 fish per cage were randomly designed as the control group and did not receive any interfere over winter. The other three cages received repeated handling with an air exposure for 5 min every week during the experiment. Fish were not fed over winter. At the end of the trial, fish were challenged with Aeromonas hydrophila at a dose of 1.5 × 10(8) CFU ml(-1). The results showed that no significant difference of final body weight was found between groups. The spleen and kidney somatic index increased in the control fish after bacterial challenge and showed a rising trend but not a statistical change in repeated handled fish. Plasma cortisol levels significantly increased in the control fish at 6 h post bacterial challenge and then declined. However, repeated handled fish did not show any significant change in plasma cortisol levels after challenge. The reduced inducement of heat shock protein 70 (HSP70) expressions by repeated handling was found in gibel carp post bacterial challenge. After overwintering, the repeated handled fish exhibited increased catalase (CAT) and superoxide dismutase (SOD) activities. Enhanced plasma CAT activities and reduced plasma malondialdehyde (MDA) contents were found in repeated handled fish over time against invading bacteria. Up-regulation of myeloid differentiation primary response gene 88 (MyD88) and interleukin 11 (IL11) was observed in repeated handled fish over time after bacterial challenge. The overexpression of IL11 was significantly reduced by repeated handling against invading bacteria compared to the control group. The present results implied that a MyD88-dependent signaling pathway was involved in the innate immune responses of gibel carp by repeated handling over winter against invading bacteria., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

An 88-day feeding trial was conducted to evaluate the effects of dietary inosine 5′-monophosphate (5′-IMP) on the growth performance and salinity and oxidative stress resistance in the juvenile gibel carp CAS III (Carassius auratus gibelio; initial body weight: 7.48 g). Four isonitrogenous and isoenergetic diets containing exogenous 5′-IMP were formulated. P1, P2, P3 and P4 were diets containing 5′-IMP at four concentrations (0, 1, 2 and 4 g kg−1). The four diets were randomly allotted to triplicate tanks in a recirculating system. After the feeding trial, six fish per tank were netted randomly and placed into 12‰ saline water to test their response to salinity stress. The results indicated that the feed conversion rate was enhanced by dietary supplementation with 5′-IMP. The appetite, plasma neuropeptide Y level and feeding rate of the P3 group were lower than those in the control treatment group. Dietary supplementation with 5′-IMP improved the osmoregulatory adaptation of gibel carp under acute salinity stress. Six hours after the salinity stress treatment, in the dietary 5′-IMP treatment group, the plasma cortisol and K+ concentrations were lower and the Na+/K+-ATPase activity was greater than that in the control group. Dietary supplementation with 5′-IMP promoted the expression of the glucocorticoid receptors NKA-α1b and NKCC and retarded the expression of Hsp70 in P4-treated gill filaments and kidneys. Dietary supplementation with 5′-IMP resulted in a stable oxidative-stress-resistant phenotype characterized by increased levels of cellular antioxidants, including SOD, catalase, glutathione peroxidase, glutathione reductase and MPO. The above results of the current study demonstrate that supplementation of 5′-IMP can promote feed utilization and have positive influences on the salinity and oxidative stress resistance of gibel carp. [ABSTRACT FROM AUTHOR]

Accurate recording of growth indicators for aquaculture species at different stages is essential for evaluating aquaculture production effectiveness and the rationality of feed formulations. Due to their convenience and non-invasiveness, weight, length, and condition factor are commonly used to assess the growth of aquaculture species. However, fish growth indicators, can vary significantly with age structure and feed components (nutrition), and relying on a single indicator may lead to misjudgments. In this study, we investigated the growth indicators of Gibel carp (Carassius auratus gibelio var. CAS V) at different growth stages (juvenile and adult) and different feed formulations. Meanwhile, the fish weight–length relationship ( W = b L a ) was used to assess the growth indicators. The results showed that the weight–length relationship of Gibel carp varied significantly with age and feed formulation. Additionally, the condition factor calculated depended on the weight–length relationship being more similar with weight and length change trend than the condition factor was measured. Weight analysis indicated that weight, length, depth, body width, and carcass ratio had higher weights when analyzing fish growth. Therefore, during aquaculture production, fish growth evaluating requires considering diverse indicators such as weight, length, body depth, body width, and carcass ratio, as well as the condition factor, to avoid misjudging the actual growth situation. Meanwhile, the use of the condition factor should consider the sufficient number of data and whether the assumptions (such as being in an isometric growth period) are met. [ABSTRACT FROM AUTHOR]

An eight-week experiment was undertaken to examine the effect of dietary hydroxyproline (Hyp) supplementation on growth performance, collagen synthesis, muscle quality of an improved triploid crucian carp (Carassius auratus Triploid) (ITCC). Six isonitrogenous (340 g/kg diet), isolipidic (60 g/kg diet) and isocaloric (17.80 MJ/kg diet) diets were formulated containing a certain amount of Hyp: 0.09% (the control group), 0.39, 0.76, 1.14, 1.53 and 1.90%. Each diet was randomly assigned to three tanks and each group was fed two times daily until apparent satiation. The results showed that growth performance and feed utilization of ITCC were significantly improved with the dietary Hyp level was increased from 0.09 to 0.76%. Crude protein, threonine and arginine content in the dorsal muscle in 0.76% hydroxyproline group were significantly higher than those in basic diet group (p < 0.05). The muscle textural characteristics increased remarkably with the amount of Hyp in the diet rising from 0.09 to 1.53% (p < 0.05). Meanwhile, the contents of type I collagen (Col I) and Pyridinium crosslink (PYD) in the muscle of fish were significantly increased by dietary Hyp (p < 0.05). The muscle fiber diameter and density of the fish were significantly increased when fed with 0.76% Hyp (p < 0.05). Furthermore, dietary supplementation with an appropriate concentration of Hyp substantially increased the expression of genes involved in collagen synthesis (col1a1 , col1a2 , p4hα1 , p4hβ , smad4 , smad5 , smad9, and tgf-β) and muscle growth (igf-1 , tor , myod , myf5, and myhc) (p < 0.05). In conclusion, dietary supplementation of Hyp can enhance fish growth performance, collagen production, muscle textural characteristics and muscle growth of ITCC. According to the SGR broken-line analysis, the recommended supplementation level of Hyp was 0.74% in the diet for ITCC, corresponding to 2.2% of dietary protein. [ABSTRACT FROM AUTHOR]

A 40‐day experiment was conducted to investigate the effects of two filamentous microalgae as feed ingredients on growth performance, tissue fatty acid profiles, pigmentation and immunity of gibel carp (204.83 ± 2.17 g, mean ± SD). Three diets (control, Oedocladium sp. and Tribonema sp.) were formulated. In the control diet, no microalgal meal was added and into the Oedocladium and Tribonema diets were added 40 g/kg Oedocladium sp. meal and 50 g/kg Tribonema sp. meal, respectively. Compared to the control, the addition of Oedocladium sp. and Tribonema sp. had significant effects on tissue fatty acid profiles, antioxidant capacity and immunity without compromising growth, body composition and pigmentation. The addition of Tribonema sp. and Oedocladium sp. significantly increased the EPA, DHA profiles and the ratio of n‐3/n‐6 polyunsaturated fatty acids, and simultaneously decreased the n‐6 polyunsaturated fatty acids profile in fish muscles. Moreover, addition of Tribonema sp. to the diet significantly increased muscle palmitoleic profile and EPA + DHA contents. Furthermore, the addition of either microalga significantly increased the total superoxide dismutase activity level and the complement 3 and immunoglobulin M contents in the plasma. These results demonstrate that Oedocladium sp. and Tribonema sp. can be used as feed ingredients to improve flesh quality and increase the immunity of fish. [ABSTRACT FROM AUTHOR]

A 12-week growth trial was conducted in a flow-through system to determine dietary selenium (Se) requirement for on-growing gibel carp (initial body weight: 76.2 ± 0.05 g, mean ± SEM). Selenomethionine was supplemented to the basal diet to formulate seven semi-purified diets containing 0.26, 0.58, 0.72, 1.14, 1.34, 1.73 and 2.09 mg Se kg−1 diet. The results showed that plasma superoxide dismutase (SOD) activity significantly increased when fish were fed with 0.58 mg Se kg−1 diet ( P < 0.05) and then decreased at 2.09 mg Se kg−1 diet ( P < 0.05). Plasma T-AOC activity was higher in fish fed with 0.72 mg Se kg−1 diet ( P < 0.05) and plasma malondialdehyde (MDA) was higher in fish fed with 0.26 mg Se kg−1 diet ( P < 0.05). When fish were fed 1.14 mg Se kg−1 diet, hepatic GSH-Px, T-AOC, GSH and CAT activities were significantly higher than those fed with 0.26 mg Se kg−1 diet ( P < 0.05). Hepatic superoxide dismutase (SOD) activity was higher at 1.34 mg Se kg−1 diet ( P < 0.05). Fish liver Se concentrations were significantly higher when fed with 0.72 mg Se kg−1 diet ( P < 0.05) and then kept constant when Se ≥ 0.72 mg kg−1 ( P > 0.05). Whole-body and muscle Se concentrations were higher when fed with 1.34 mg Se kg−1 diet ( P < 0.05) and kept a plateau when Se ≥ 1.34 mg kg−1 ( P > 0.05). In conclusion, based on broken-line regression of hepatic Se concentrations, hepatic SOD activity and hepatic T-AOC activity, dietary Se requirements for on-growing gibel carp was 0.73 mg kg−1, 1.12 mg kg−1 and 1.19 mg kg−1 diet respectively. [ABSTRACT FROM AUTHOR]

An 84-day growth trial was designed to investigate effects of dietary replacements fish oil with pork lard ( PL) or rapeseed oil ( RO) on growth and quality of gibel carp ( Carassius auratus gibelio var. CAS III) (initial body weight: 158.2 ± 0.2 g), and responses of the fish refed fish oil ( FO) diet. Three isonitrogenous (crude protein: 30%) and isolipid (crude lipid: 10%) diets were formulated containing 7.73% FO, PL or RO. Five experimental treatments including FO group ( FO), PL group ( PL), RO group ( RO), group fed PL for 42 days and refed FO for 42 days ( PL+ rFO), RO and refed FO group ( RO+ rFO) was tested. At the end of first 42 days, the fish fed PL and RO had higher mortality than that of the control ( P > 0.05). At the end of whole experiment, fish fed PL and RO showed higher plasma cortisol than FO fish ( P < 0.05). RO+ rFO fish showed higher lysozyme activity than RO fish ( P < 0.05). Fish growth and feed utilization, composition of whole body and muscle, free amino acids, texture, off-flavour substances or sensory attributes were not affected by dietary treatments ( P > 0.05). PL and RO diet decreased muscle EPA, DHA and n-3/n-6 ratio ( P < 0.05), while FO-refeeding had recovery effect. It can be concluded that the replacement of FO by PL and RO does not affect the growth, feed utilization or fish tasting quality in gibel carp. Fish muscle fatty acids modified by dietary PL and RO can be recovered by refeeding with FO diet. [ABSTRACT FROM AUTHOR]

A 8 week growth trial of three feeding frequencies (2, 4 and 6 meals day-1) and three dietary protein levels (30%, 34% and 38%) was conducted to investigate the influence of feeding frequency and dietary protein level on growth, feed utilization, serum free essential amino acids (EAA) dynamics and nitrogen (N), phosphorus (P), carbon (C) retention in juvenile allogynogenetic gibel carp (Carassius auratus gibelio) 'CAS III'. The results showed that feeding frequency and dietary protein level increased feed intake (FI), specific growth rate (SGR) and feed efficiency (FE). SGR increased significantly with the increase in feeding frequency and dietary protein level. But, the increase in dietary protein level from 30% to 38% in group 6 meals day-1 did not result in better growth. Compared with the group of 4 meals day-1 × 38%, the fish fed the diet containing 30% crude protein at 6 meals day-1 obtained similar SGR but showed lower FIp (protein intake). Compared with 2 meals day-1, NREs (nitrogen retention efficiency) of 4 and 6 meals day-1 were relatively higher. PRE (phosphorus retention efficiency) and CRE (carbon retention efficiency) increased significantly with feeding frequency while TNW (total nitrogen waste output), TPW (total phosphorus waste output) and TCW (total carbon waste output) decreased significantly. Feeding frequency and dietary protein level increased trypsin activity. Serum free EAA concentrations varied more synchronously at 6 meals day-1 than 2 meals day-1. It could be concluded that increasing feeding frequency could improve growth by increasing feed intake and feed efficiency for juvenile gibel carp. The increase in feeding frequency showed proteinsparing effect. [ABSTRACT FROM AUTHOR]

A 60-day growth trial was conducted to investigate the effect of dietary protein levels on growth performance, digestive enzyme activities, transaminase activities and GH-IGF-I axis gene expression of broodstock gibel carp (initial body weight, 180.3 ± 0.4 g) using diets containing white fishmeal and casein as the main protein sources. Six isolipidic (100 g kg − 1 ) and isoenergetic (gross energy 17.5 kJ g − 1 ) diets were prepared, with protein levels ranging from 200 to 400 g kg − 1 at 40 g kg − 1 increments. Each diet was fed by hand to triplicate groups of 22 fish each to apparent satiation four times a day. Results indicated that specific growth rate (SGR), feed efficiency (FE) and protein retention efficiency (PRE) significantly increased with the increase of dietary protein levels from 200 to 360 g kg − 1 , after that, SGR and FE plateaued while PRE notably decreased. Whole-body and muscle crude lipid increased and moisture decreased with increasing dietary protein levels; whereas crude protein and ash in whole-body and muscle, condition factor, vicerosomatic index and hepatosomatic index showed no obvious differences between treatments. Plasma ammonia concentration, hepatic alanine transaminase and aspartate transaminase activities markedly enhanced with the increase of dietary protein level up to 320–360 g kg − 1 . Intestinal trypsin activity peaked in fish fed protein level of 320 g kg − 1 , and then remarkably descended; while no significant differences were observed in intestinal lipase and α-amylase. The relative mRNA abundance of insulin like growth factor-I (IGF-I) in liver notably up-regulated with dietary protein level increasing to 360 g kg − 1 , and down-regulated at higher protein level. Pituitary growth hormone (GH) mRNA showed an almost opposite trend with IGF-I. In conclusion, based on a broken-line analysis of SGR, the recommended dietary protein level for broodstock gibel carp was 369 g kg − 1 , which was higher than that for sub-adult fish. Statement of relevance This study provides basic data of nutritional requirement for broodstock gibel carp. [ABSTRACT FROM AUTHOR]

A 16S rDNA-based polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method was applied to detect intestinal bacterial communities of juvenile allogynogenetic crucian carp, Carassius auratus gibelio, fed with chitosan-containing diet. This is the first time to use the molecular method to analyze the bacterial communities in the allogynogenetic crucian carp intestine. The DGGE profile with universal bacterial primers revealed simple communities in all treatment groups. Sequencing and phylogenetic analysis of excised DGGE bands showed that the dominant bacteria belonged to class γ-Proteobacteria and Fusobacteria. The relative abundance and diversity of detected bacteria suggested that 0.5 and 0.75% of chitosan in diet were optimum for juvenile allogynogenetic crucian carp. As in these concentrations, some detected pathogen bacteria either disappeared or decreased. However, the DGGE profile with Aeromonas-specific primers showed a similar composition among all treatment groups, which suggested that Aeromonas was one of relative stable bacteria components in the intestine of juvenile allogynogenetic crucian carp. [ABSTRACT FROM AUTHOR]

The compensatory responses of juvenile gibel carp and Chinese longsnout catfish to four cycles of 1 week of feed deprivation and 2 weeks of satiation feeding were quantified as part of a study designed to determine feeding regimes that would maximise growth rates. Both species showed compensatory growth in the re-feeding periods. The compensation was not sufficient for the deprived fish to match the growth trajectories of controls fed to satiation daily. The compensatory growth response was more clearly defined in the later cycles. The deprived fish showed hyperphagia during the 2-week periods of re-feeding and the hyperphagic response was clearer in the later cycles. The hyperphagia tended to persist for both weeks of the re-feeding period. The gibel carp showed no difference in gross growth efficiency between deprived and control fish. In the catfish, the gross growth efficiency of the deprived fish was marginally higher than that of control fish, but the efficiency varied erratically from week to week. Over the experiment, the deprived fish achieved growth rates 75–80% of those shown by control fish, although fed at a frequency of 66%. There was no evidence of growth over-compensation with the deprivation–re-feeding protocol used in this study. [Copyright &y& Elsevier]

To test the hypothesis that response to insulin by regulating glucose and lipid metabolism in gibel carp A strain may be different from that in DT strain, bovine insulin was injected into both strains of gibel carp after previous fasting for 48 h. The results showed that insulin induced hypoglycemia at 3 h in 2 strains, and that this was coupled with increased expression of glucose transporters (GLUT2 in the liver and GLUT1, GLUT4 in the muscle) and glycolytic enzyme (HK2 in the muscle) in both strains. Insulin induced increased glycolysis (GK) and fatty acid oxidation (ACO3 in the liver and CPT1a, ACO3 in the muscle) in the DT strain. Conversely, very strong lipogenic capacity, as indicated by higher mRNA levels of transcription factor of fatty acid anabolism (SREBP1) and lipogenic enzymes (ACC, ACLY, and FAS) and decrease lipolytic capacity as indicated by lower mRNA levels of fatty acid oxidation enzymes in the liver (ACO3) and muscle (CPT1a and ACO3) detected in the A strain after insulin injection. Higher plasma insulin levels and decreased plasma free fatty acid levels were detected at 8 h post insulin injection in A strain induced hypoglycemia. However, plasma glucose levels returned to baseline and no effect on fatty acid levels in the DT strain was observed in response to insulin treatment at the same point in time. These insulin-strain interactions demonstrated that insulin induced different changes in glucose and lipid metabolism in these 2 strains as expected. [ABSTRACT FROM AUTHOR]

Abstract: A 16-week feeding trial was conducted to evaluate the effect of dietary aflatoxin B1 (AFB1) on growth, physiological responses, histological changes, and accumulation in gibel carp (Carassius auratus gibelio), and the recovery when the fish were fed basal diet without supplemental chemical AFB1. Triplicate groups of gibel carp with initial body weight of 10.33±0.19g were fed seven semipurified diets (Diets 1 to 7) designed to contain 0, 10, 20, 50, 100, 200, 1000μg AFB1 kg−1 diet (determined level was 3.2, 11.3, 20.2, 55.2, 95.8, 176.0, 991.5μg AFB1 kg−1 diet, respectively) for 12weeks. Subsequently, all fish were fed Diet 1 for another 4weeks. The results showed that, after 12weeks of AFB1 exposure, average body weight in fish fed Diet 4 was 112.3% of that of the control group (Diet 1), but there was no significant difference between other groups and the control group. No external changes, unusual behavior or significant difference in mortality were observed in the fish fed with various levels of AFB1. There was no significant difference in feeding rate (FR) between the control and experimental groups. Specific growth rate (SGR) and feed efficiency (FE) of the fish fed with Diet 4 was significantly higher than that fed the control diet during the first exposure period (weeks 0–4) while there were no significant difference during the second exposure period (weeks 5–12). Fish fed with various levels of AFB1 showed no significant differences in activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), superoxide dismutase (SOD), total protein, total serum cholesterol, and hematocrit compared to the control group. No significant histological lesions were identified between the control and increasing AFB1 treatments. Low AFB1 residues were found in muscles, whereas high residues of AFB1 were determined in hepatopancreas (above the safety limitation of 5μgkg−1), which was logarithmically related to the dietary AFB1 levels. Our results indicate that gibel carp is a less susceptible species to AFB1 exposure up to approximately 1000μg AFB1 kg−1 diet, at least for 12weeks. The fish also showed strong clearance ability of AFB1 during recovery period. [Copyright &y& Elsevier]