Carassius Auratus Gibelio Var Research Articles

Weight–Length Relationship and Condition Factor of Gibel Carp (Carassius auratus gibelio var. CAS V) at Different Growth Stages and Feed Formulations

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=bLa) 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.

Effects of Astragalus membranaceus extract and Eucommia ulmoides leaf extract on growth performance, blood biochemistry, and antioxidant capacity of gibel carp juveniles (Carassius auratus gibelio var. CAS V)

The study aims to investigate the effects of dietary Astragalus membranaceus extract (AME) and Eucommia ulmoides leaf extract (ELE) supplementation on the growth performance, blood biochemistry, and antioxidant capacity of gibel carp (Carassius auratus gibelio var. CAS V, 10.01 g ± 0.24 g). Six experimental diets supplemented were marked as A0E0 (basic diet, 0% AME and 0% ELE), A0E0.1 (0% AME and 0.1% ELE), A0.02E0, A0.02E0.05, A0.02E0.1, A0.02E0.2 (0.02% AME with 0%, 0.05%, 0.1%, and 0.2% ELE). After 8 weeks, A0.02E0 diet significantly increased the final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR), and decreased the glucose (GLU), triglyceride content (TG), and total cholesterol (TC) of the plasma, the malonaldehyde (MDA) content of the liver, the A0E0.1 group significantly increased the total protein (TP) and albumin (ALB) content of the plasma, decreased the alanine aminotransferase (ALT) content of the plasma when compared with A0E0 group (Independent T-test: P < 0.05). A0.02E0.1 group significantly increased the FBW, WGR, SGR, and decreased the moisture of the whole body when compared with A0E0.1 group (Independent T-test: P < 0.05). One-way ANOVA analysis showed that 0.02% AME with different levels of ELE (0.05%, 0.1% and 0.2%) significantly increased FBW, SGR, WGR, the crude protein and crude lipid of whole body, the GLU, TP, ALB, TC, and TG content of the plasma, and the activities of the lysozyme, total superoxide dismutase, and catalase (CAT) of the liver when compared with A0.02E0 diet (Tukey’s test: P < 0.05). Two-way ANOVA analysis showed that the AME and ELE showed significantly interaction effect on FBW, WGR, SGR, GLU content, TG content, TC content, ALT content, CAT activity. In conclusion, it could be recommended that AME and ELE interaction can be used for growth promotion and antioxidant capacity improvement in aquaculture animals.

Appropriate leucine supplementation promotes glucose metabolism and enhances energy homeostasis in juvenile crucian carp (Carassius auratus gibelio var. CAS III)

In order to characterize the molecular mechanisms by which leucine regulates carbohydrate metabolism and energy homeostasis, juvenile crucian carps (Carassius auratus gibelio var. CAS III) fed with a high carbohydrate diet were supplemented with different levels of dietary leucine: 0% (Leu0), 0.4% (Leu4), 0.8% (Leu8), 1.2% (Leu12), 1.6% (Leu16), 2.0% (Leu20), and 5.0% (Leu50). After 8 weeks, RNA sequencing was performed on samples collected from the Leu0, Leu8, Leu12 and Leu50 groups. Differentially expressed genes were then detected and analyzed. The results showed a total of 91.6 Gb of clean bases were generated. Moreover, a total of 1131, 5254, and 1539 DEGs were detected in Leu8, Leu12, and Leu50 compared with Leu0, respectively, encompassing 161 common DEGs. STEM analysis elucidated four significant clusters of DEGs that were associated with “glycerophospholipid metabolism,” “glycerolipid metabolism,” “PPAR signaling pathway,” and “adipocytokine signaling pathway.” Moreover, the mRNA expression levels of acyl-CoA synthetase long chain family member 5 (ACSL5), choline kinase beta (CHKB), cryptochrome-1 (CRY1), lon protease homolog 2, peroxisomal isoform X2 (LONP2), lipin 1 (LPIN1), membrane bound O-acyltransferase domain containing 2 (MBOAT2), phosphoenolpyruvate carboxykinase 1 (PEPCK), and uridine-cytidine kinase 2b (UCK2b) were then further investigated in all leucine treatment groups at starvation times of 0 h, 24 h, and 48 h. The results revealed that the expression levels of UCK2b and MBOAT2 were negatively correlated with the addition of leucine, whereas CHKB, LONP2, CRY1, PEPCK, and LPIN1 were positively correlated. In conclusion, dietary leucine supplementation below 1.2% enhanced carbohydrate metabolism in juvenile crucian carp fed with a high-carbohydrate diet, whereas concentrations above 2.0% is a better choice for energy homeostasis under starvation.

Dietary supplementation with fermented plant meal enhances growth, antioxidant capacity and expression of TOR signaling pathway genes in gibel carp (Carassius auratus gibelio var. CAS V)

This study assessed the nutritional potential of supplementing the practical diets for gibel carp (Carassius auratus gibelio var. CAS V) with a blend of fermented plant meal. The fermented plant meal (FPM) comprised mixed fermentation of rapeseed meal (RM), sprayed corn husk (SCH), rice bran (RB), palm meal (PM) and soybean meal (SM) in the proportion of 30:25:25:15:5. Four experimental diets were including a basal diet (the control diet, Con) and three FPM diets (supplementing 3 g, 5 g and 8 g FPM per 100 g diet in the basal diet, FPM3, FPM5 and FPM8, respectively). Each diet was randomly allotted to triplicate fish tanks where each tank had 25 fish weighing 28.00 ± 0.02 g. Fish from each group were fed twice per day until apparent satiation for 60 days. From the results, gibel carp from the FPM5 group had significantly higher feed efficiency and specific growth rate despite having significantly lower feeding rate than the control group. Fish from FPM5 group had significantly higher hepatosomatic index and viscera somatic index than those from FPM3 group. Meanwhile, serum antioxidants (including aspartate aminotransferase, catalase, glutathione peroxidase, superoxide dismutase and malondialdehyde) and intestinal digestive enzymes (including chymotrypsin, trypsin and amylase) of fish increased proportionately to amount of FPM in the diet. Fish fed on FPM5 diet had significantly higher expression of TOR and IGF-1 in the liver than those fed on the control diet. Further, supplemented with 8% of FPM significantly increased the relative mRNA abundance of hepatopancreas GH and S6K1. These results reveal that moderate level of dietary FPM significantly enhanced growth performance, antioxidant capacity, digestive enzymes activities and the expression of TOR signaling pathway genes of juvenile gibel carp, and dietary supplementation of 5% FPM is recommended for the juveniles base on the performance of growth and antioxidant properties.

Effects of dietary supplementary leucine in a wheat meal‐rich diet on the growth performance and immunity of juvenile gibel carp ( Carassius auratus gibelio var. CAS III)

Leucine has been reported to regulate key metabolic pathways, including growth, immunity and antioxidative defence. To study the effects of dietary leucine supplementation in a carbohydrate‐rich diet on juvenile gibel carp (Carassius auratus gibelio var. CAS III), an 8‐week feeding trial was conducted on gibel carp juveniles reared on an experimental wheat meal‐rich diet (40%) with varying leucine contents (0.87%, 1.23%, 1.68%, 2.10%, 2.41% and 2.83%). No significant changes in growth performance were observed regardless of leucine levels (p > 0.05). However, proper leucine levels (1.68% and 2.10%) could increase the accumulation of whole‐body crude protein and decrease the accumulation of crude lipid. Furthermore, significant liver tissue damage occurred at 1.23% and 1.68% dietary leucine levels, whereas 2.10% and 2.41% dietary leucine could improve the antioxidant capacity at the end of the 8‐week feeding trial. 1.68% and 2.10% dietary leucine levels could alleviate the hyperglycaemia caused by high carbohydrate intake after the 8‐week feeding trial, as well as the elevated glucose content after starvation, to maintain normal metabolic conditions. Supplementation with leucine could significantly downregulate IL‐1β, TNF‐α1, MyD88 and TIRAP mRNA levels during the 8‐week feeding trial and after starvation for 48 h. In conclusion, 2.10%–2.41% leucine contents in a carbohydrate‐rich diet could benefit muscle protein deposition, hyperglycaemia and hyperlipidaemia alleviation, and results in non‐specific immunity improvement.

Optimal form of yeast cell wall promotes growth, immunity and disease resistance in gibel carp (Carassius auratus gibelio)

A 63-day feeding trial was conducted to explore dietary yeast cell wall (YCW) on growth, immunity and disease resistance against Aeromonas hydrophila in gibel carp (Carassius auratus gibelio var. CAS Ⅲ) (initial body weight: 8.49 ± 0.27 g). Four isonitrogenous and isoenergetic diets were formulated to contain 0 % or 0.4 % three types of yeast cell wall (YCW) (termed as YCW0, YCW1, YCW2 or YCW3, respectively). Fish were randomly divided into 4 feeding groups in triplicates of 22 fish in each tank. Results showed that the highest final body weight was observed in fish fed YCW3 diet than the control (P < 0.05). Compared to the control group, significantly higher FE was found in groups of YCW2 and YCW3 (P < 0.05). There were no significant differences in feeding rate, specific growth rate, protein retention rate and energy retention rate among treatments (P > 0.05). Dietary supplementation of YCW decreased condition factor, hepatosomatic index and viscerosomatic index (P < 0.05). Dietary addition of YCW3 significantly increased serum complement C3 compared to control group (P < 0.05). The relative expression of complement C3 in liver was significantly upregulated in fish fed YCW3 supplemented diet (P < 0.05). Dietary YCW1 significantly increased lysozyme C mRNA level (P < 0.05). The relative expressions of TNF-α1 and IL-8 were not significantly affected by YCW inclusion in the diet (P > 0.05). Hepatic IL-1β and TGF-β expressions were significantly down-regulated in the fish fed YCWs (P < 0.05). Furthermore, dietary administration of YCW1 and YCW3 could to some extent improve disease resistance against bacterial challenge. Based on growth performance and immunity, 0.4 % YCW3 was recommended in the gibel carp diet.

Effects of dietary fish meal replacement by fermented moringa (Moringa oleifera Lam.) leaves on growth performance, nonspecific immunity and disease resistance against Aeromonas hydrophila in juvenile gibel carp (Carassius auratus gibelio var. CAS III)

This study was aimed to evaluate the effects of partial replacement of fish meal by fermented moringa leaves (FMLs) on growth performance, serum biochemistry, antioxidant status, nonspecific immunity, and resistance against Aeromonas hydrophila in juvenile gibel carp (Carassius auratus gibelio var. CAS III). Four isonitrogenous and isoenergetic balanced diets, including three FML diets (substituting 20%, 40%, 60% of the fish meal in basal diet, F20, F40 and F60, respectively) and a basal diet (a diet containing 10% fish meal) were used. Each diet was randomly allocated to four fish groups (F20, F40, F60 and control) reared in a recirculating system. After 50 days of the feeding trial, fish were challenged by A. hydrophila. The result revealed that final mean body weight (FBW), weight gain rate (WGR), specific growth rate (SGR), feed efficiency (FE) and survival rate (SR) were significantly increased (P < 0.05) in F20 and F40 groups compared with the control group. Decreased hepatosomatic index (HSI), body crude lipid, serum aspartate transaminase (AST) and serum alanine aminotransferase (ALT) activities, and increased serum alkaline phosphatase (AKP) and serum glutathione peroxidase (GPx) activities were observed in F40 and F60 groups compared with the control and F20 groups. All FMLs-supplemented groups increased (P < 0.05) serum superoxide dismutase (SOD), catalase (CAT) and lysozyme activities, complement component 3 (C3) and serum immunoglobulin M (IgM) concentration, or decreased serum malondialdehyde (MDA) and protein carbonyl (PCC) contents (P < 0.05). After the challenge test, the significant downregulation of toll-like receptors2 (TLR2), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-8 mRNA transcription levels was observed in spleens of FMLs supplemented groups. Dietary F40 and F60 showed higher (P < 0.05) relative percent survival (RPS) (48.72% and 43.59%, respectively) against A. hydrophila infection than control. These results indicate that, as a dietary fish meal substitute, FMLs enhance the growth, and antioxidant and immune response, and regulate the expression of immune-related genes and increase disease resistance against A. hydrophila via TLR2 pathway in gibel carp, with greatest effects of 40% fish meal substitution.

Effects of inosine 5′-monophosphate supplementation in high fishmeal and high soybean diets on growth, immune-related gene expression in gibel carp (Carassius auratus gibelio var. CAS Ⅲ), and its challenge against Aeromonas hydrophila infection

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.

Effect of biofloc technology on water quality and feed utilization in the cultivation of gibel carp (Carassius auratus gibeliovar. CAS III)

This study was designed to use sucrose as carbon source to investigate the effect of biofloc technology on water quality and feed utilization in the cultivation of gibel carp (Carassius auratus gibelio var. CAS III). Three isolipidic and isoenergetic diets were formulated containing graded levels of dietary protein (257.4, 300.7 and 353.4 g/kg). The control group (P34) was fed with 353.4 g/kg protein diet without biofloc. Three biofloc treatments (P24 + B, P29 + B and P34 + B) were fed with the three diets with daily sucrose supplementation and continuous air inflation. The results found that the sucrose supplementation could generate biofloc and increased biofloc volume (BFV, p < 0.05). The concentration of total ammonia nitrogen (TAN), nitrate nitrogen (NO3-N) and the total phosphorus (TP) of all tanks decreased in biofloc groups, and the total nitrogen (TN) of P24 + B treatment tanks was significantly lower than that of the control group (p < 0.05). The growth of P24 + B and P29 + B group was similar with that of control group (p > 0.05). Feed conversion ratio (FCR) of P29 + B was lower than P24 + B and P34 + B (p < 0.05). Protein retention efficiency (PRE) of P24 + B group was significantly higher than other treatments (p < 0.05). Phosphorus retention efficiency (PhRE) of P24 + B group was the highest among all treatments. Compared with the control group, P29 + B group had an improved total antioxidant capacity (T-AOC), superoxide dismutase (SOD) activity and contained the lowest malondialdehyde level (MDA). The present results indicated that low-protein diet is more suitable for gibel carp in zero-water exchange biofloc system compared with high-protein diet.

Replacement of fishmeal by spirulina Arthrospira platensis affects growth, immune related-gene expression in gibel carp (Carassius auratus gibelio var. CAS III), and its challenge against Aeromonas hydrophila infection

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.

Comparative study on dietary protein requirements for juvenile and pre-adult gibel carp (Carassius auratus gibelio var. CAS III)

Two 8-week growth trials were conducted in indoor recirculation system to evaluate the protein requirements for juvenile (3.70 ± 0.20 g) and pre-adult (85.2 ± 0.70 g) gibel carp, Carassius auratus gibelio var. CAS III. Six isoenergetic diets were formulated for each trial using fish meal and casein as protein sources, and protein level was 250–450 g kg−1 in Trial 1 and 200–450 g kg−1 in Trial 2. With the increasing dietary protein, feeding rate (FR) and feed conversion ratio (FCR) significantly decreased (P 0.05), while decreased after the maximum value in 350 g kg−1 in Trial 2 (P 0.05). Hepatic alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in both trials increased when dietary protein was above 400 g kg−1 (P < 0.05). Based on quadratic regression of WG, it was estimated that dietary protein requirement for maximum growth was 414 g kg−1 (digestible protein of 376 g kg−1) and 365 g kg−1 (digestible protein of 324 g kg−1) for juvenile (3.70 g) and pre-adult gibel carp (85.2 g).

Effects of total replacement of fish oil by pork lard or rapeseed oil and recovery by a fish oil finishing diet on growth, health and fish quality of gibel carp (Carassius auratus gibelio)

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.

Comparative studies on dietary protein requirements of juvenile and on-growing gibel carp (Carassius auratus gibelio) based on fishmeal-free diets

Two trials were conducted to investigate protein requirements of juvenile (3.18g in Trial 1) and on-growing (87.1g in Trial 2) gibel carp, Carassius auratus gibelio var. CAS III. Six isoenergetic diets containing 250-500gkg(-1) dietary protein were formulated using soy protein concentrate (SPC) and casein as protein sources. The results showed that weight gain (WG) increased when dietary protein increased from 250 to 400gkg(-1) and decreased at 400 to 500gkg(-1) CP in Trial 1, while WG increased when dietary protein increased from 250 to 350gkg(-1) and kept constant at 350 to 500gkg(-1) CP in Trial 2. With increasing dietary protein, feed conversion ratio (FCR) decreased, while protein retention efficiency (PRE) decreased in Trial 1 and was not affected in Trial 2. Apparent digestibility coefficient of protein (ADC(p)) increased with increasing dietary protein in two trails. Trypsin activity increased with dietary protein in the juveniles and was not affected in on-growing fish. Hepatic alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities increased with dietary protein. Broken-line and quadratic regression of WG estimated that dietary protein requirements for maximum growth were about 402-427gkg(-1) for the juvenile and 337-418gkg(-1) for on-growing gibel carp.

Assessment of antibacterial properties and the active ingredient of plant extracts and its effect on the performance of crucian carp (Carassius auratus gibelio var. E'erqisi, Bloch)

In this study, the antibacterial properties and active ingredient of plant extracts and its effect on the performance of crucian carp (Carassius auratus gibelio var. E'erqisi, Bloch) were assessed. The transmission electron microscopy and flow cytometric analysis showed that the antibacterial activity of plant extracts is due to the disruption of the cell membrane and the leakage of cytoplasmic contents. The UPLC-MS/MS analysis showed that the contents of gallic acid, (-)-epigallocatechin, (+)-catechin, (-)-epigallocatechin gallate, (-)-epicatechin gallate, aloe-emodin, rhein, emodin, chrysophanol, and physcion, were 5.27%, 3.30%, 1.08%, 19.32%, 5.46%, 0.23%, 0.56%, 1.28%, 0.75% and 0.39% in plant extracts, respectively. Results of feeding experiment showed that feeding crucian carp with 1.0% and 2.0% plant extracts significantly enhanced specific growth rate, serum total protein, lysozyme, catalase and superoxide dismutase activities, and decreased the feed conversion rate, malondialdehyde contents and the mortality rate (P < 0.05). It can be concluded that plant extracts added to fish feed can act as natural antimicrobial and immunostimulants to prevent pathogenic infection, enhance immune response, and promote growth of the fish.

Cloning and Sequencing of Full Length Growth Hormone cDNA from &lt;I&gt;Carassius auratus gibelio var&lt;/I&gt;*

Cloning and Sequencing of Full Length Growth Hormone cDNA from &lt;I&gt;Carassius auratus gibelio var&lt;/I&gt;*