鲤 IGF-I 基因 2 个高度多态微卫星位点的鉴定及其与生长相关性 状的关联分析

??利用PCR结合测序方法, , 在鲤(Cyprinus carpio)类胰岛素生长因子-I (insulin-like growth factor-I, , IGF-I)基因内含子1和内含子2中各鉴定1个微卫星多态性位点, , 分别命名为intron1189和intron2310, , 这两个位点均以4碱基为重复单元。以黑龙江鲤(Cyprinus cario haematopterus, , YL)(n=263)、德国镜鲤选育系(Cyprinus carpio L. mirror, , JL)(n=229), 及荷包红鲤抗寒品系(Cyprinus carpio var. wuyuanensis, , HL)(n=255)为研究对象, , 评估了这两个位点不同基因型(频率>3%)与鲤4个生长时段(135 d 、325 d、335 d和445 d)生长表型的关联。结果显示, , 2个位点在3个鲤群体中均表现为高度多态(PIC>0.5)。intron1189位点多态性主要对YL的135 d、325 d体长和325 d、385 d体质量有显著影响(P<0.05), , 而intron2310位点多态性对JL各检测时段的体长和体质量均有显著影响(P<0.05)。对不同基因型个体的体长和体质量性状进行多重比较, , 结果显示, , 在intron1189位点, , 185/229基因型YL的135 d、325 d体长和325 d、385 d体质量最低, , 而205/221基因型YL的135 d、325 d体长和325 d体质量最高。在intron2310位点, , 290/350基因型JL在各检测时段的体长及135 d、325 d、385 d体质量最低, , 而318/350基因型JL的135 d、325 d、385 d体长和体质量均为最高。上述结果表明, , 鲤IGF-I基因内含子中的这两个高度多态微卫星位点潜在影响鲤的生长性能。

     

A combination of rapeseed,cottonseed and peanut meal as a substitute of soybean meal in diets of Yellow River carp Cyprinus carpio var

A feeding trial was conducted to evaluate the results of replacing soybean meal (SBM) with other blend plant protein (BP) (rapeseed meal, cottonseed meal and peanut meal) sources on growth, fish body composition, biochemical parameters, non‐specific immune index and gene expression of growth hormone/insulin‐like growth factor‐1 in Yellow River carp Cyprinus carpio. The results showed that the 600 g/kg replacement with BP in diet did not affect the growth performance of Yellow River carp, but the 800 g/kg SBM replacement diet could depress the growth of fish (p < .05). The 800 g/kg SBM replacement diet significantly impacted the superoxide dismutase, malondialdehyde contents, lysozyme, alanine aminotransferase and aspartate aminotransferase activities (p < .05). Fish fed 800 g/kg SBM replacement diet showed lowest insulin‐like growth factor 1 and highest growth hormone level than that of other diets (p < .05). Both gene expression levels of GH and IGF‐I in hepatic showed significant difference among dietary treatments (p < .05), and the lowest GH and IGF‐I mRNA level in liver were found in fish fed 800 g/kg SBM replacement diet (p < .05). In conclusion, no more than 600 g/kg SBM could be replaced by BP in diet of Yellow River carp without adverse effects on the growth performance. However, 800 g/kg SBM replacement with BP in diet inhibited the growth performance, affected some blood parameters and immune response index, and down‐regulated GH and IGF‐1 gene expression of liver in Yellow River carp. Further, GH level in serum was negatively correlated with GH mRNA level in liver; meanwhile, serum concentrations of IGF‐I were positively correlated with hepatic IGF‐I mRNA expressions.     

Identification of a novel cyprinid herpesvirus 3 genotype detected in koi from the East Asian and South‐East Asian Regions

Cyprinid herpesvirus 3 (CyHV‐3) is a highly contagious virus that causes significant morbidity and mortality in common carp Cyprinus carpio L. and considered to be one of the most important pathogens of koi and common carp worldwide. Cyprinid herpesvirus 3 infected consignments imported from East Asian and South‐East Asian regions were identified during quarantine period in Singapore, and virus from a 2005 consignment was successfully isolated in koi fin cells. A combination of sequence analyses and duplex PCR were used to characterize 15 CyHV‐3 isolates detected in koi consignments between 2005 and 2011. Sequence analyses of the enlarged 9/5, SphI‐5 and TK gene regions identified both the Asian 1 (n = 11) and European 4 (n = 4) genotypes. Duplex PCR analysis of two variable marker regions between ORF29 and ORF30 (marker I) as well as ORF133 and its upstream region (marker II) revealed viruses of genotypes J (I⁺⁺II⁺), U/I (I⁻⁻II⁻), an intermediate genotype (I⁺⁺II⁻) and a novel genotype, I⁺⁺II^+Δ, which was identified in viruses from seven different consignments. This novel genotype has a 13‐bp deletion in marker II, while maintaining the I⁺⁺ allele of marker I. The I⁺⁺II^+Δ genotype may have emerged from East Asian and South‐East Asian regions in recent years.     

Response of the intestinal mucosal barrier of carp (Cyprinus carpio) to a bacterial challenge by Aeromonas hydrophila intubation after feeding with β‐1,3/1,6‐glucan

The effect of dietary β‐glucan on the bacterial community in the gut of common carp (Cyprinus carpio) was examined after oral application of Aeromonas hydrophila. Carp received either feed supplemented with 1% MacroGard^®, a β‐1,3/1,6‐glucan, or a β‐glucan‐free diet. Fourteen days after feeding, half of the carp from each group were intubated with 10⁹ colony‐forming units (CFU) of a pathogenic strain of A. hydrophila. Gut samples were taken 12 hr to 7 days after application and analysed using microbiological and molecular biological techniques (NGS, RT‐PCR‐DGGE). The reaction of the mucosa and the microbiota to an A. hydrophila intubation differed in carp fed with β‐glucan compared to carp from the control group. In β‐glucan fed carp, the total bacterial amount was lower but the number of bacterial species was higher. Bacterial composition was different for carp from both treatment groups. The number of mucin filled goblet cells was reduced in carp fed the β‐glucan diet. Mucus was obviously released from the goblet cells and was probably washed out of the gut together with high numbers of bacteria. This might be protective against pathogenic bacteria and, therefore, feeding with β‐glucan may provide protection against infections of the gut in carp.     

Recombinant expression and comparative bioactivity of tongue sole insulin‐like growth factor (IGF)‐1 and IGF‐2 in Pichia pastoris

Insulin‐like growth factor (IGF) plays a key role in the complex system that regulates bony fish growth, differentiation, and reproduction. In the current study, recombinant tongue sole IGF‐1 and IGF‐2 were obtained using the Pichia pastoris expression system and their comparative bioactivities were investigated. Tricine–SDS–PAGE and western blot analysis showed that the recombinant tongue sole IGFs were secreted into the culture medium and had a molecular weight of 8.7 kDa. The optimal incubation time and pH for recombinant expression of IGFs were 36 hr and 5.0 respectively. Functional analysis demonstrated that both recombinant tongue sole IGF‐1 and IGF‐2 significantly promoted cell proliferation of MFC‐7 in vitro. In addition, the recombinant tongue sole IGF‐1 and IGF‐2 proteins could suppress hepatic mRNA levels of igf‐1 and igf‐2 in vitro, which showed that they have similar physiological functions. Taken together, the biologically active recombinant tongue sole IGF‐I and IGF‐II proteins will allow us to further investigate their physiological roles in growth regulation of this species. Furthermore, the present results also hinted at the potential application of these two recombinant IGF‐I and IGF‐II proteins into the tongue sole farming industry.     

Effects of temperature and dietary protein on the growth performance and IGF‐I mRNA expression of juvenile mirror carp (Cyprinus carpio)

Juvenile mirror carp were fed with five different diets containing 303, 322, 341, 361 and 379 g kg^?1 protein and reared at three different water temperatures (18, 23 and 28 °C) for 60 days. We investigated the insulin‐like growth factor I (IGF‐I) mRNA expression, growth performance and the relationship between IGF‐I mRNA expression and the growth performance. The results indicated that the IGF‐I mRNA expression, final body weight, specific growth rate (SGR) and feed efficiency (FE) were enhanced significantly with increasing dietary protein levels (P < 0.05), whereas the protein efficiency ratio, hepatosomatic index (HSI) and viscerosomatic index (VSI) were decreased. Moreover, the IGF‐I mRNA expression, final body weight and SGR were increased significantly with temperature, whereas the HSI and VSI indices were decreased significantly with temperature. Correlation analysis showed that the IGF‐I mRNA expression levels in the brain and liver were positively related to the SGR and FE growth indices (P < 0.01). Finally, the optimal protein requirements for fish growth in different seasons were determined based on the values of SGR and FE, that is 343–348 g kg^?1 protein at 18 °C, 354–352 g kg^?1 at 23 °C and 371–362 g kg^?1 at 28 °C. In this way, we can adjust the dietary protein levels according to culture temperature to reduce any negative impacts on dietary costs and environmental pollution.     

Effects of antimicrobial peptides on growth,morphology of foregut villi and related genes mRNA expression in the common carp (Cyprinus carpio)

A 60‐day feeding trial was conducted to examine the effects of different levels (0, 100, 200, 400 and 600 mg/kg) of antimicrobial peptides on growth, protease activity of foregut, the morphology of foregut villi and related genes mRNA expression level in the common carp (Cyprinus carpio). The results showed that the feed of antimicrobial peptides promote common carp growth, and the optimal dosage of antimicrobial peptides is 200–333 mg/kg in the common carp feed. The protease activity of 200 and 400 mg/kg groups were significantly higher than the control and other groups (p < 0.05). The foregut villus height with 100, 200 and 400 mg/kg antimicrobial peptide groups were significantly higher than control group (p < 0.05). The crypt depth of 200 and 400 mg/kg antimicrobial peptide groups were significantly lower than control group (p < 0.05). The ratio of villus height and crypt depth of 100, 200 and 400 mg/kg antimicrobial peptide groups were significantly higher than control group (p < 0.05). The ratio with 600 mg/kg group was significantly lower than the control group (p < 0.05). The IGF‐I gene expression level of 200 mg/kg and 400 mg/kg groups were significantly higher than the control group and 600 mg/kg group (p < 0.05). The IL‐1β gene expression level of 100 mg/kg and 200 mg/kg groups were significantly higher than the control group (p < 0.05). These results indicated up‐regulation of growth and immune related genes in antimicrobial peptides fed common carp. Correlation analysis showed that IGF‐I mRNA and IL‐1β mRNA were positively correlated with SGR. IL‐1β mRNA and FCR were significantly negative correlated. It indicated that growth and immune gene common regulated the growth of the carp under antimicrobial peptides intervention. In conclusion, antimicrobial peptides can improve growth and related genes mRNA expression in the common carp. Further studies using molecular biological technique or immunologic methods are required to conclude that antimicrobial peptides are beneficial in common carp.     

Characterization of β‐catenin 1 during the gonad development in the common carp (Cyprinus carpio)

β‐catenin gene is a pivotal gene for gonad development and maintenance of ovarian function in mammals. However, little is known about its expression and function in gonad development of fish. In this study, a complete cDNA (3342 bp) sequence of β‐catenin 1 was cloned from the common carp, Cyprinus carpio, by RACE PCR, which encodes a 780‐amino‐acid protein. Quantitative real‐time PCR demonstrated that β‐catenin 1 mRNA expressions were high in the testis and ovary tissue and the expression increased as the testes developed and the early stage ovaries developed. Western blot results revealed a single immunoreactive band with an estimated molecular weight of 90 kDa in testes. Immunohistochemistry analysis revealed that the β‐catenin 1 protein was concentrated mainly in the cytoplasm of early development stage of oocyte cells and in the cytomembrane of developing and mature sperm cells. 17β‐Ethinylestradiol injecting intraperitoneally into the fish decreased the relative β‐catenin 1 mRNA expression level except 1 μg/g 72 hr and 5 μg/g 48 hr of treatments in the ovary by real‐time PCR. These results suggest, for the first time, that β‐catenin 1 is an essential protein in gonad development and might be involved in ovarian early development of C. carpio.     

Dietary protein requirement for large‐size Songpu mirror carp (Cyprinus carpio Songpu)

Dietary protein requirements of large‐size Songpu mirror carp (Cyprinus carpio Songpu) were investigated through an an 82‐day feeding trial. Six practical diets were formulated to contain increasing crude protein levels of 240, 260, 280, 300, 320 and 340 g/kg. Six triplicate groups of fish (25 individuals per replicate with initial mean weights of 246.00 ± 17.36 g) were reared in the floating net cages. Results indicated that the highest weight gain rate (WGR), specific growth rate (SGR), protein efficiency ratio (PER) and lowest feed conversion ratio (FCR) were observed in the 260 g/kg treatment. The whole‐body crude protein content was significantly higher in the 260 and 280 g/kg treatments (p < .05). The expression of growth hormone (GH) in dorsal white muscle, Rh a glycoprotein (Rhag), Rh b glycoprotein (Rhbg) and Rh c glycoprotein 1 (Rhcg1) in gills increased significantly with increasing protein levels, while the expression of target of rapamycin (TOR), eukaryotic translation initiation factor 4E binding protein 1 (4EBP1) and S6 kinase (S6K) in muscle and intestine increased first and then decreased significantly. Based on these findings, 260 g/kg seems to be the proper level of protein in a practical diet for large‐size Songpu mirror carp (Cyprinus carpio Songpu).     

Comparative effect of Freund's adjuvant and Aloe vera L. gel on the expression of TNF‐α and IL‐1β in vaccinated Cyprinus carpio L. with Aeromonas hydrophila C. bacterin

The comparative effects of Freund's and Aloe vera gel as adjuvants on the expression of IL‐1β and TNF‐α genes were studied in vaccinated common carp (Cyprinus carpio) with Aeromonas hydrophila bacterin. Fishes were intraperitoneally immunized with A. hydrophila bacterin in combination with Aloe vera gel or Freund's and also without any adjuvant. At day 28 after immunization, all groups were challenged by lethal dose of A. hydrophila (10⁷ cells/fish). Changes in the expression of IL‐1β and TNF‐α genes were evaluated in anterior kidney before challenge and 12, 24, 72 and 7 days postchallenge using quantitative real‐time PCR. Higher expression levels of both genes were observed in all vaccinated groups compared with non‐immunized group. Fishes which received Aloe vera gel showed higher expression of IL‐1β and TNF‐α in relation to animals which vaccinated with or without Freund's adjuvant. We concluded that Aloe vera gel in compared with Freund's adjuvant had a more stimulatory effect on the expression of immune‐related genes in vaccinated common carp and it can use as a novel adjuvant in aquaculture.     

Modulation of growth performances,survival, digestive enzyme activities and intestinal microbiota in common carp (Cyprinus carpio) larvae using short chain fructooligosaccharide

This study investigates the effects of inclusion of low levels of dietary short chain fructooligosacchairde (sc‐FOS) on physiological response and intestinal microbiota of carp (Cyprinus carpio) larvae. After acclimation, fish (550 ± 20 mg) were allocated into nine tanks (40 fish per tank) and triplicate groups were fed a control diet (0%) or diets containing 0.5% and 1% sc‐FOS for 7 weeks. At the end of the experiment, the growth performance parameters (final weight, weight gain, specific growth rate (SGR), food conversion ratio (FCR) and condition factor (CF), survival rate as well as digestive enzyme activities (amylase, lipase and protease), total viable counts of heterotrophic aerobic bacteria (TVC) and lactic acid bacteria (LAB) level in intestinal microbiota were measured. Our results revealed no significant (P > 0.05) effects of sc‐FOS on growth performance and TVC when compared with the control group. However, administration of low levels of dietary sc‐FOS significantly increased digestive enzyme activities (lipase and amylase) and LAB levels (P < 0.05). Also, survival rate was significantly elevated in sc‐FOS fed carp. These results revealed that administration of low levels of sc‐FOS can be considered as a beneficial dietary supplement for larval stage of common carp.     

Sesbania aculeata leaf meal as replacer of de‐oiled rice bran in aquaculture feed: Growth,IGF‐1 expression,metabolic and biochemical responses in Cyprinus carpio (Linnaeus 1758)

A feeding trial was conducted to evaluate the effect of inclusion of Sesbania leaf meal in the diet of Cyprinus carpio as a replacer of de‐oiled rice bran (DORB). Bacillus subtilis was used to ferment the Sesbania leaf meal (SLM) to produce FSLM (fermented sesbania leaf meal). Fishes were fed with five isonitrogenous (30% CP) and isocaloric diets for 60 days and treatments were viz., C (30% DORB, 0% SLM), R15 (15% DORB, 15% SLM), R30 (0% DORB, 30% SLM), F15 (15% DORB, 15%FSLM) and F30 (0% DORB, 30% FSLM) by replacing DORB with SLM. A similar growth performance with control was observed in 15% FSLM group while there was a growth reduction in all the raw leaf meal fed groups. Similarly, the expression of insulin‐like growth factor‐1 (IGF‐1) was significantly (p < .05) higher in control and 15% FSLM fed groups. Growth and metabolic enzymes such as protease, amylase, ALT and AST activities were significantly higher in the fermented leaf meal fed groups compared to their non‐fermented counterparts. Antioxidant enzymes, serum transaminase enzymes (SGOT, SGPT) and total bilirubin (TBR) were found to be increased by enhanced level of RSLM, however, reduced by inclusion of FSLM. However, 30% inclusion level of FSLM even after fermentation showed detrimental effect on growth and metabolic response at cellular and molecular level. Thus, the results concluded that fermented Sesbania leaf meal (FSLM) using B. subtilis could replace 50% DORB (15% FSLM group) in the diet of C. carpio without affecting the growth and other physiological responses.     

Replacement of de‐oiled rice bran by soaked and fermented sweet potato leaf meal: Effect on growth performance,body composition and expression of insulin‐like growth factor 1 in Labeo rohita (Hamilton), fingerlings

A 60‐day feeding trial was conducted to determine the growth performance and expression of insulin‐like growth factor 1 gene (IGF‐I gene) in Labeo rohita fingerlings fed with either raw, soaked or fermented sweet potato leaf meal (SPLM) by completely replacing de‐oiled rice bran (DORB), following a completely randomized design. Seven isonitrogenous (30%) and isocaloric (1.8 MJ/100 g) diets were prepared by replacing DORB with 50% and 100% raw, soaked and fermented sweet potato leaf meal, maintaining DORB‐containing diets as a control. Weight gain %, SGR (specific growth rate) and PER (protein efficiency ratio) were significantly (p < 0.05) higher when 100% DORB was replaced by fermented SPLM in comparison to other treatment groups. The fermented and soaked SPLM‐fed groups had registered with lower FCR value. The expression of growth regulating gene IGF‐I mRNA and RNA/DNA ratio was found to be significantly higher (p < 0.05) in soaked and fermented SPLM‐fed groups. In this study, the body protein and lipid composition did not vary significantly (p > 0.05). Hence, the study concludes that the fermented sweet potato leaf meal using Chaetomium globosum can replace 100% DORB in the diet of Labeo rohita without any detrimental effect on growth performance.     

Identification of growth‐related nucleotide polymorphism in cultured Pacific bluefin tuna,Thunnus orientalis

Pacific bluefin tuna (PBF), Thunnus orientalis, is commercially one of the most important species of tuna. In this study, amplified fragment length polymorphism (AFLP) screening was conducted to find the growth‐related polymorphic DNA in cultured PBF. Fish hatched in 2007 were harvested at an age of 818–1994 days. They were categorized into superior, average and inferior growth groups, depending on their growth score at the time of harvest. On AFLP screening of 24 fish, with eight fish from each group, 215 polymorphic DNA fragments were observed. A second amplification, with EcoRI + ACC and MseI + CCC primers, generated a polymorphic fragment of 630 bp at a rate of 80.0% (n = 15) in the superior, 56.3% (n = 16) in the average and 20.0% (n = 15) in the inferior growth groups. Polymerase chain reaction (PCR) primers, which could amplify both AFLP‐positive and AFLP‐negative loci, were developed using the consensus sequence outside the AFLP target fragment. Eleven haplotypes were obtained by sequence analysis of the PCR product at the AFLP target loci. Among those, haplotype 1 was statistically significant in the superior and average growth groups and could be used as a molecular marker for distinguishing the individuals with superior and average growth from those with inferior growth.     

Effect of dietary supplementation of palm fruit extracts on the transcriptomes of growth,antioxidant enzyme and immune‐related genes in common carp (Cyprinus carpio) fingerlings

This study investigates the effects of date palm extracts [DPE] (Phoenix dactylifera L. Arecaceae) on growth, immune function and antioxidant system in common carp fingerlings (Cyprinus carpio). One hundred and twenty fish (4.06 ± 0.13 g) were divided into six groups fed on control diet or diets containing 200 mL kg^?1 DPE for 8 weeks. At the end of feeding trial, the expression of different genes was measured. Selected genes were grouped into three categories: growth factor genes in brain and liver [growth hormone (GH), insulin‐like growth factors I and II (IGF‐I and IGF‐II), antioxidant‐related genes in liver [glutathione S‐transferase‐alpha (GST‐α), glutathione reductase (GR) and glutathione peroxidase genes (GPX)] and immune‐related genes in head kidney [interleukin‐8 (IL‐8), interleukin‐10 (IL‐10) and transforming growth factor‐beta (TGF‐β) genes]. The relative expression of the growth‐related genes in fish fed DPE showed no significant increase compared to control group (P > 0.05). On the other hand, DPE altered the expression of genes encoding antioxidants enzymes in liver of fingerlings which was statistically significant with respect to the control samples in case GPX (P < 0.05). Also, DPE caused remarkable increases in the expression of the immune‐related genes (IL‐8, IL‐10 and TGF‐β) analysed on head kidney of common carp fingerlings compared to the control group (P < 0.05). In conclusion, it can be suggested that administration of DPE in early stages of common carp culture can promote immune efficacy and increase the antioxidant activity.     

Optimization of de‐oiled rice bran inclusion level in the diet of Labeo rohita: Effect on growth performance,nutrient utilization,insulin‐like growth factors I and II gene expression

A 60‐day feeding trial was conducted to optimize the inclusion level of de‐oiled rice bran (DORB) in the diet of Labeo rohita fingerlings. Six iso‐nitrogenous (260g/kg), iso‐lipidic (70g/kg) and iso‐energetic (15 MJ/Kg) diets were prepared with different inclusion level of DORB viz., T33, T38_, T43, T48, T53 and T58. One hundred and eighty fingerlings (9.8 ± 0.5 g) were randomly distributed in seven experimental groups in triplicates following a completely randomized design. The weight gain %, specific growth rate, protein efficiency ratio and feed efficiency ratio were found similar in 33%, 38% and 43% DORB fed groups. The expression of both insulin‐like growth factors I and II (IGF‐I and II) was significantly (p < 0.05) higher in T33, T38 and T43 groups. Based on second order polynomial regression analysis (y = ?0.0059x² + 0.4573x ? 4.8404, R² = 0.95), the expression of IGF‐I was found to be maximum at 39.5% inclusion level of DORB. Significantly (p < 0.05) lower muscle RNA content, RNA‐DNA ratio and higher feed conversion ratio were found in T58 group. Hence, from these results, it can be concluded that the optimum inclusion of DORB in the diet (260g/kg CP and 70g/kg lipid) of L. rohita should be 39.5% to support maximum nutrient utilization and growth performance.     

Effects of oral passive immunization against somatostatin‐14 on growth performance,body composition and IgY delivery in rainbow trout (Oncorhynchus mykiss) and common carp (Cyprinus carpio)

Egg‐yolk antibodies (IgY) against somatostatin‐14 (anti‐SST‐14) were evaluated as orally administered, growth promotants in gastric rainbow trout (Oncorhynchus mykiss) and agastric common carp (Cyprinus carpio) in an 8‐week feeding trial. Feeding groups were compared with fish which did not receive anti‐SST‐14 IgY. Growth responses and IgY plasma contents of the blood were assessed. In contrast to rainbow trout, oral anti‐SST‐14 addition to carp significantly improved protein efficiency ratio (PER, 1.02 ± 0.04) and protein productive value (PPV, 26.7 ± 0.91) after 56 days (P < 0.05) compared to the negative control (PER = 0.91 ± 0.02; PPV = 22.9 ± 0.66). IgY was undetectable in plasma of rainbow trout after oral administration, indicating that gastric degradation of the fed IgY makes this application route for growth promotion in gastric trout challenging.     

Effect of dietary Houttuynia cordata leaf meal and leaf extract on the growth performance,nutrient utilization and expression of IGF‐I gene in Labeo rohita

A 60‐day feeding trial was conducted to evaluate the effects of feeding Houttuynia cordata leaf meal and extract on the growth performance, nutrient utilization and expression of insulin‐like growth factor‐I (IGF‐I) in Labeo rohita fingerlings. Two hundred seventy fingerlings were randomly distributed in six experimental groups in triplicates. Six isonitrogenous (350 g/kg CP) and isocaloric (17 MJ/kg DE) diets were prepared with graded levels of leaf meal (LM) and leaf extract (LE), namely C (control, without LE and LM), LE‐0.25 (2.5 g/kg LE), LE‐0.5 (5 g/kg LE), LE‐1.0 (10 g/kg LE), LM‐1.0 (10 g/kg LM) and LM‐2.0 (20 g/kg LM). Significantly (p < 0.05) higher IGF‐I expression, weight gain %, specific growth rate and lower feed conversion ratio were observed in LM‐1.0 followed by LE‐1.0 group compared to control group. Higher protease activity was observed in LE‐1.0 compared to other experimental groups, while no significant changes were found for amylase and lipase activities. Compared to control, muscle alanine aminotransferase and aspartate aminotransferase activities were significantly higher in treatment groups except for LM‐2.0. These results suggest that either LE‐1.0 or LM‐1.0 can be supplemented in the diet to improve the growth of L. rohita. However, the supplementation of 10 g H. cordata leaf meal/kg feed can be the better option considering the cost of extraction.     

Effects of partial replacement of fishmeal with blood meal and dried porcine soluble on the growth,body composition and intestinal morphology of Cyprinus carpio

A 12‐week feeding trial was conducted to assess the impact of fishmeal replacement with blood meal or dried porcine solubles on the growth performance, body composition and intestinal morphology of common carp (Cyprinus carpio). Fishmeal was 50% substituted with either blood meal or dried porcine solubles, or two‐third substituted with both alternative products, at a 1:1 ratio. There was no significant difference in survival, final weight, weight gain ratio, feed conversion ratio or condition factor between the control and experimental groups (p > .05), although the visceral somatic index of the blood meal group was higher than that of the control group (p < .05). Crude lipid content was significantly higher in the dried porcine soluble group than that in the control group (p < .05), while other nutrient levels were not significantly different (p > .05). The amino acid composition of each experimental group was not significantly different from that of the control (p > .05). The intestinal villus height and fold depth of each experimental group were significantly lower than those of the control group (p < .05). The results of this study show that two‐third fishmeal substituted with both blood meal and dried porcine solubles, at a 1:1 ratio, is the optimal fishmeal replacement for common carp growth.     

The induction of Hsp70 synthesis by non‐lethal heat shock confers thermotolerance and resistance to lethal ammonia stress in the common carp,Cyprinus carpio (Linn)

Exposure to heat‐shock protein (Hsp) stimulating factors induces Hsp accumulation and confers tolerance to lethal ammonia stress on the common carp Cyprinus carpio. This study investigated whether a non‐lethal heat shock bestowed similar protective effects against ammonia and induced thermotolerance, both thought to be rendered by increased amounts of Hsps. The 30‐min lethal temperature (30 min LHT) and 1‐h lethal ammonia concentration (1 h LCT) for this species occurred at 41°C and 14.2 mg/L NH₃ respectively. Heating juvenile carp (5 cm) from 28°C to 32, 34 and 38°C, with a subsequent 8‐h recovery period augmented tolerance to lethal heat and ammonia perturbation by two to threefold as compared with animals held at 28°C. Protection occurred in conjunction with Hsp70 accumulation in gills, substantiating the role of this Hsp in enhancing the stress tolerance of common carp.