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1.
The pituitary adenylate cyclase activating polypeptide (PACAP) is a new type of hypophysiotropic hormone and plays an important role in regulating the synthesis and secretion of growth hormone and gonadotropin. The research on the relationship between PACAP and different growth traits would contribute to explain its function during the process of growth. Moreover, epigenetic modifications, especially DNA methylation at the CpG sites of the SNPs, play important roles in regulating gene expression. The results suggest that a SNP mutation (c.C151G) in the PACAP gene of male half smooth tongue sole (Cynoglossus semilaevis) is significantly associated with growth traits and serum physiological and biochemical parameters such as inorganic phosphorus (P < 0.05). The SNP is located in a CpG-rich region of exon 1. Intriguingly, the transition (C→G) added a new methylation site of PACAP gene. This SNP was also significantly related to the expression and methylation level of PACAP (P < 0.05). Individuals with GG genotype had faster growth rates than those of CG and CC genotypes. Moreover, GG genotype had significantly higher PACAP expression level and lower methylation level than CG and CC genotypes. In the serum indexes, only inorganic phosphorus content within GG genotypes was significantly higher than CC genotypes. This implied that the mutation and methylation status of PACAP gene could influence growth traits and this locus could be considered as a candidate genetic or epigenetic marker for Cynoglossus semilaevis molecular breeding.  相似文献   

2.
Molecular markers that allow selection of juveniles and broodstock with a high growth performance are useful for the aquaculture industry. In this study, association between single nucleotide polymorphisms (SNPs) of the Activin type IIB receptor (LcActRIIB) and growth-related parameters of Asian seabass Lates calcarifer juveniles were examined by PCR-direct sequencing. Three SNPs (G>Ac.965+g.7, C>A>T c.965+g.33 and G>A c.965+g.189) generating seven composite SNP genotypes (diplotypes) were found in the LcActRIIB gene segment (398 bp). Among three identified SNPs, only a G>Ac.965+g.7 SNP showed significant association with growth traits (average body weight, total length, hepatic weight and hepatosomatic index) of examined fish (P < 0.01). Significant association between diplotypes and growth-related parameters were found. Juveniles exhibiting diplotypes I–V showed greater growth-related parameters than those exhibiting diplotypes VI (P < 0.001; N = 57). Simple methods for rapid genotyping of a G>Ac.965+g.7 SNP were successfully developed based on gel-based bi-allelic PCR amplification of specific alleles (Bi-PASA) and real-time PCR-based PASA analyses (N = 99). Identical genotypes were consistently obtained from different detection methods.  相似文献   

3.
The aim of this study is to screen single nucleotide polymorphisms (SNPs) of the farnesoic acid O‐methyltransferase gene in shrimp, Penaeus chinensis (PcFAMeT), and analyze the potential association between PcFAMeT gene polymorphisms and growth traits in a cultured population. Four SNPs (A163G, G392T, A708G, and T752C) were tested for association with six growth traits in 240 individuals using the polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) method. The association analysis of SNPs of PcFAMeT gene with the six growth traits was carried out using general linear model estimation. Results indicated that SNP2 (G392T) of the PcFAMeT gene was significantly associated with body weight (P < 0.05) and carapace width (P < 0.05). The individuals of genotype GG grew faster than those of genotype GT and TT. The results would provide potential application in future shrimp breeding programs and may be used to improve the efficiency in shrimp, P. chinensis, breeding programs.  相似文献   

4.
通过佛山市白金水产良种选育场提供的草鱼EST库的醛缩酶B基因重叠群的2个Contig扩增该基因的序列片段,采用直接测序法,经过序列比对,共筛到C+687G、C+1042A和A117C等3个颠换SNPs位点。C+687G位于醛缩酶B基因外显子6的63 bp处,为同义突变;C+1042A位于外显子8的43 bp处,为错义突变;A117C位于内含子7的117 bp处。采用Snapshot方法对同一群体的296尾草鱼的这3个SNPs位点进行检测和分型,并统计基因型频率。3个SNPs位点中AA的频率分别为42.9%、32.8%、32.8%;AB的频率分别为42.9%、45.9%、45.6%;BB的频率分别为14.2%、21.3%、21.6%。利用一般线性模型分析3个SNPs位点与草鱼体质量、体长等重要生长性状的关系,关联分析结果显示,C+687G位点不同基因型只在体长/尾柄长比值上存在显著差异(P0.05),和体质量等重要生长性状不相关。A117C和C+1042A两个位点都在体质量等4个生长性状上存在显著差异(P0.05)。将3个SNPs位点不同基因型两两位点组成3个组合的双倍型(都去掉了频率小于3%的组合),结果显示,C+687G和A117C以及C+687G和C+1042A的2个组合分别组成的7种双倍型在体质量等5个生长性状上都存在显著差异(P0.05);A117C和C+1042A组成的3种双倍型在体质量、眼间距等2个生长性状上都存在显著差异(P0.05)。研究认为,可以考虑将草鱼醛缩酶B基因作为生长相关的候选基因,用于草鱼的分子辅助育种。  相似文献   

5.
三疣梭子蟹生长相关 SNP 位点的鉴定   总被引：2，自引：0，他引：2  
为了发掘三疣梭子蟹(Portunus trituberculatus)与生长相关的SNP,本研究基于三疣梭子蟹比较转录组学数据,筛选出生长相关候选基因片段19条,利用该基因序列设计引物进行PCR扩增,得到总长为17 387 bp的DNA片段;通过直接测序法发现74个SNP位点,分布频率为0.43/100 bp,其中转换突变的比例为80%,颠换突变的比例为20%,转换的比例远远大于颠换,符合"transition bias"原理。C/T(G/A)突变所占比例为60%,G/T(C/A)突变占20%,A/T突变占9.33%,G/C突变占10.67%,C/T(G/A)突变所占比例最大。内含子上突变发生的频率为1.34/100 bp,外显子上仅为0.17/100 bp,说明外显子上的碱基更加保守。通过飞行质谱法,在三疣梭子蟹生长性状分离群体中成功分型了10个SNP位点;通过卡方检验和多元方差分析的方法进行性状关联分析,发现3个SNP位点与生长性状显著相关(P0.05),并且comp58070-R31位点与生长性状极显著相关(P0.01);一般线性模型的多元方差分析显示,comp58070-R31位点与体重、全甲宽、甲宽3个性状极显著相关(P0.01),与体长、体高2个性状为显著相关(P0.05);comp46623-F49位点与甲宽显著相关(P=0.05);comp49193-R333位点与甲宽显著相关(P0.05)。通过对SNP位点的多态性分析发现,三疣梭子蟹SNP标记观测杂合度(Ho)范围为0.162 8~0.833 3,期望杂合度(He)范围为0.189 6~0.591 2,并且显示SNP标记的信息量低于微卫星标记。该研究的结果将有助于推进三疣梭子蟹分子标记辅助育种进程。  相似文献   

6.
缢蛏EGFR基因内含子1内SNP位点多态性与生长性状相关性   总被引：1，自引：1，他引：0  
为研究缢蛏表皮生长因子受体基因(epidermal growth factor receptor,EGFR)单核苷酸多态性(single nucleotide polymorphism, SNP)与生长性状(壳长、壳宽、壳高和体质量)的相关性。本实验利用直接测序法从缢蛏EGFR基因的第一个内含子序列中共筛选到17个SNP位点。卡方检验结果显示,在17个位点中,有13个位点符合Hardy-Weinberg平衡,位点多态性检测显示17个位点中有10个位点表现为中等多态性(0.25PIC0.5)。利用一般线性模型(general linear model,GLM)及多重比较对缢蛏EGFR基因中17个SNPs的多态性与生长性状(壳长、壳宽、壳高和体质量)进行相关性分析,结果显示,16个SNP位点均与缢蛏的壳长、壳宽、壳高及体质量呈显著性相关。由此可见,EGFR基因可作为缢蛏生长性状改良的候选辅助分子标记,并且为进一步研究其生长相关功能奠定基础。  相似文献   

7.
Genetic diversity and correlation analysis between single nucleotide polymorphism (SNP) of myostatin (MSTN) gene and the growth traits were performed in Argopecten irradians. Around 279 individuals from three A. irradians populations were screened for the polymorphic sites of the MSTN gene. Two SNPs were found: T910G and G1162A. The observed heterozygosity of the two SNPs ranged from 0.1310 to 0.3299, whereas the expected heterozygosity ranged from 0.1436 to 0.2973. The values of D′ and r2 of linkage disequilibrium (LD) ranged from 0.475 to 1.0 and 0.052 to 0.174 respectively. Association analysis shows that individuals with genotype TT and TG of locus W4 had significantly higher adductor muscle mass than that with genotype GG in population CA (P < 0.05). Individuals with genotype AA of locus W5 had significantly higher body mass, soft‐tissue mass, adductor muscle mass, shell width and shell mass than those of other genotypes in population RZ (P < 0.05). The two SNPs found in our study can be used for molecule marker‐assisted breeding of A. irradians.  相似文献   

8.
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9.
Growth rate is one of the important economic traits in aquaculture species that is influenced by quantitative trait loci (QTLs). Recently published complete genetic map of common carp (Cyprinus carpio) with 307 markers (including 109 SSR, 31 EST-SSR and 167 SNP markers) was used to determine the number and position of QTLs effecting body weight (BW) and growth rate. Ten-, 11- and 12-month-old individuals of common carp were measured, and seven QTLs were detected in three linkage groups (LG1, LG6 and LG20); three were significant QTLs (qBW2-6, qBW3-6 and qBW3-20, P < 0.001), and four were suggestive QTLs (qBW1-1, qBW1-6, qBW2-20 and qBW3-1, P < 0.01). The three significant QTLs related to BW2 and BW3 were in LG6 and LG20 and covered 18 and 41 cM, respectively. The explained variances of qBW2-6, qBW3-6 and qBW3-20 were 34.4, 32.1 and 33.4 %, respectively. The four suggestive QTLs affecting BW1, BW2 and BW3 were in LG1, LG6 and LG20 and had variances that ranged from 17.9 to 26.7 %. The similarity of the QTL intervals for BW1, BW2 and BW3 in LG6 suggested that these genes may affect growth continuously during the early stage of growth and may be important for growth. The identification of QTLs for growth rate and BW in C. carpio will lead to a better understanding of the factors that influence these traits at a genetic level and will promote the growth to higher production through marker-assisted breeding.  相似文献   

10.
We evaluated the effects of diets incorporating the red algae Pyropia yezoensis, prepared by several different extraction methods, on the growth of juvenile Japanese flounder Paralichthys olivaceus. We assessed growth performance, as well as the levels of amino acids, fatty acids, insulin-like growth factor I (IGF-I) and interleukins (ILs). Four experimental diets were developed based on different methods of processing P. yezoensis. A commercial feed, laver powder (P), high-pressure heat extraction of laver (HPHE) and acid hydrolysis extraction of laver were used as the experimental diets. Three experimental replicates were established for each diet (40 fish/group, body weight 123.7 ± 1.1 g), and the fish were fed for 6 weeks. We found no significant differences in weight gain, specific growth rate or feeding efficiency among the groups (P > 0.05); however, the fish fed HPHE had the greatest growth performance. Fish fed the laver extracts exhibited the highest protein efficiency ratio compared with the control and P groups. The experimental groups fed P. yezoensis extracts had significantly higher levels of IGF-I (P < 0.05) than those of the control group. High levels of IL-2 were found in the P and HPHE groups, IL-12 in the HPHE group, and IL-6 in all experimental groups. Therefore, these results suggest that a P. yezoensis extract improved the growth performance and immunity of Japanese flounder. In particular, the high-pressure heating process was a useful extraction method for preparing a P. yezoensis extract, which had beneficial effects as a dietary supplement in Japanese flounder.  相似文献   

11.
Cultured sea urchins of similar size (mean ± SE = 4.33 ± 0.48 g in body weight) were fed biofilms only, kelp (Laminaria japonica)+biofilms (biofilms as supplementary food) and a control diet of kelp only for 7 months in the laboratory. The somatic growth and the survival rate of the sea urchins were measured monthly, and the gonad wet weight and gonad color difference were determined at the end of the experiment. The results show that diet did not significantly affect survival rate (P > 0.05), but had highly significant effects on somatic growth from the first month to the end of the experiment (P < 0.01). Sea urchins fed biofilms only showed negligible or even negative somatic growth at the end of the experiment. Sea urchins on the kelp+biofilms grazed biofilms and consumed kelp during the experiment, and showed sustained greater increase in body weight than those of fed kelp only after the fourth month (P < 0.05). The biofilms may have supplied micronutrients. At the end of the experiment, gonad production of sea urchins fed biofilms was too little (0.11 ± 0.09 g) to identify sex and measure color. Gonad wet weights of males and females and gonad color fed kelp+biofilms did not differ significantly from those of fed kelp only (P > 0.05). However, sea urchins fed kelp+biofilms were more uniform in gonad color than those fed kelp only (P < 0.01), indicating biofilms supplementation could reduce the percentage of low-grade roe. This study therefore reveals the potential of biofilms as a supplementary food in the culture of sea urchins.  相似文献   

12.
A 2 × 3 factorial study was conducted to investigate the effects of dietary protein levels (DPLs) and feeding rates (FRs) on the growth and health status of juvenile genetically improved farmed tilapia (GIFT), Oreochromis niloticus. Triplicate tanks of fish (initial weight 15.87 ± 0.11 g) were fed diets containing 25 or 35% protein at rates of 3, 5, or 7% body weight per day (BW day?1) for 8 weeks. At the end of the feeding trial, the results showed that fish growth (final mean weight 34.61–81.07 g) and condition factor (3.39–4.45 g cm?3) increased with the DPLs and FRs. Feed efficiency (FE, 0.48–0.88) increased as DPLs increased but decreased as FRs increased; the opposite trend was observed for feed cost (FC, 3.24–5.82 CHN Yuan kg?1) and hepatosomatic index (0.98–2.33%). Apparent protein retention efficiency (APRE, 23.92–38.78%) was reduced by high FR. A 35% protein diet resulted in higher (P < 0.05) FE and APRE, and lower (P < 0.05) FC at 5% BW day?1 than those at 7% BW day?1. As FRs increased, lipid contents of the hepatopancreas, viscera, muscle, and eviscerated body increased, while moisture contents of hepatopancreas and viscera decreased. All serum biochemical parameters, including glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase activity and levels of creatinine, glucose, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, triglyceride, and total protein were unaffected by DPL or FR (P > 0.05), except urea nitrogen levels, which were affected by DPLs (P < 0.05). Moreover, the size of hepatocytes and the area ratio of hepatocyte vacuoles were enlarged (P < 0.05), whereas the area ratios of the nucleus and cytoplasm were reduced (P < 0.05) with increasing FRs. These results suggested that the optimal feeding strategy for juvenile GIFT is 35% protein diet at 5% BW day?1.  相似文献   

13.
This study examined the effects of a commercial Bacillus complex used as probiotics on the performance of Marsupenaeus japonicus under high water temperature after 60 days of rearing. Growth and survival rate of M. japonicus were significantly increased in the probiotics-treated group (P < 0.05). Vibrio count and percentage of Vibrio in the intestinal tracts of M. japonicus reared with Bacillus were significantly lower than in other treatments (P < 0.05). The expressions of immune-related gene including prophenoloxidase, lysozyme, cytosolic manganese superoxide dismutase and hemocyanin subunit L in M. japonicus were significantly increased in the Bacillus-treated group (P < 0.05). The results indicated that Bacillus can be used as a diet supplement to minimize the damages caused by free radicals generated from insufficient oxygen metabolism due to the high-temperature stress, and to enhance immunity and activate the immune response levels. Our findings can improve the growth and survival rates of M. japonicus during the high-temperature farming period.  相似文献   

14.
In the present study, konjac mannanoligosaccharide (KMOS) was evaluated as a prebiotic in yellow catfish. The fish were fed with diets containing KMOS in four concentrations: 0 g kg?1 (C), 1.0 g kg?1 (KM1), 2.0 g kg?1 (KM2), and 3.0 g kg?1 (KM3) for 49 days, respectively. Another group fed with diets containing 3.0 g kg?1 yeast cell wall mannanoligosaccharide (MOS) (M3) was set as positive control. The results indicated that fish receiving the diets supplemented with KMOS or MOS showed higher relative gain rate (RGR), specific growth rate (SGR), and lower feed conversion ratio (FCR) with significantly differences (P < 0.05) than those fed with the basal diets. Moreover, fish receiving the diets with 2.0 g kg?1 KMOS inclusion showed higher RGR, SGR, and lower FCR (P < 0.05) than that feeding the diets supplemented with 3.0 g kg?1 MOS. The quantities of Bifidobacterium spp. were significantly increased (P < 0.05). Meanwhile, Escherichia coli and Aeromonas spp. were significantly reduced (P < 0.05) in the fish-feeding diets with 2.0 g kg?1 KMOS supplement. Compared with the control group, the significantly enhancement of protease and amylase activity (P < 0.05) in intestine and pancreas was observed in fish fed with diets containing KMOS or MOS. Collectively, an optimum level of KMOS inclusion in diets could modulate intestinal microflora, induce digestive enzyme activity, and improve the growth performance of yellow catfish significantly.  相似文献   

15.
In this study, the effects of dietary tryptophan (a precursor of 5-hydroxytryptamine, 5-HT, serotonin) on the agonistic behavior, growth, and survival of freshwater crayfish were investigated. For this aim, a control diet (D1) and three experimental diets (D2, D3, and D4) were prepared. D1 contained no additional tryptophan (TRP), but D2, D3, and D4 diets were supplemented with TRP at 0.50, 0.75, and 1.00 % in dry diet, respectively. The control contained 0.33 % TRP. Results revealed that higher supplemental dietary TRP levels caused a significant decrease in the aggressive behavior (P < 0.05), but an increase in the calmness of crayfish. In addition, the results showed that 5-HT levels in the hemolymph before the fight (after 15 days of feeding; resting) were significantly different (P < 0.05) between D1 and D4. There was a significant difference (P < 0.05) in the 5-HT level of hemolymph between the crayfish fed control and D4 after 15 days of feeding. However, after the fight, 5-HT concentration was significantly higher (P < 0.05) in TRP-supplemented A. leptodactylus as compared with the control. The findings of this study showed that supplemental dietary TRP caused a significant increase (P < 0.05) in the growth and survival rate of A. leptodactylus. The crayfish fed D4 had the best survival rate at the end of the experiment (91.60 % in August). The findings of this study also showed that difference in survival rate between the crayfish fed control and D2 in June, July, and August was not significant (P > 0.05). In addition to these, supplemental dietary TRP gave rise to significantly higher specific growth rate (SGR) values in June and July (P < 0.05). For example, in June, it was 0.38 for the crayfish fed D4, 0.28 for the crayfish fed D3, 0.18 for the crayfish fed D2, and 0.13 for the crayfish fed control. However, in August, the highest SGR (0.56) was obtained from the crayfish fed control. The results also showed that the SGRs of females were lower than the males in June, July, and August (P < 0.05). In conclusion, this research shows that the aggressive behavior of A. leptodactylus can be suppressed, and rearing efficiency (i.e., increased growth and high survival rate) of this species can be improved by increasing TRP levels to 1.00 % in its diet.  相似文献   

16.
This study was conducted to investigate the effects of dietary chitosan on growth performance, hematological parameters, intestinal histology, stress resistance and body composition in the Caspian kutum (Rutilus frisii kutum, Kamenskii, 1901) fingerlings. Fish (1.7 ± 0.15 g) were fed diets containing chitosan at different levels (0, 0.25, 0.5, 1 and 2 g kg?1 diet) for a period of 60 days. Results showed that the feed conversion ratio significantly decreased in fish fed diet containing 1 g kg?1 of chitosan compared to the other groups (P < 0.05), but there were no significant differences between treatments in terms of specific growth rate and condition factor (P > 0.05). Leukocyte increased in fish fed diet containing 2 g kg?1 of chitosan compared to the other groups (P < 0.05). Lymphocytes, eosinophils and neutrophils did not significantly change among dietary treatments (P > 0.05). Also, the chitosan supplementation did not affect the whole-fish body composition (P > 0.05). Light microscopy demonstrated that the intestinal villus length increased in fish fed diet containing 1 g kg?1 of chitosan compared to control group (P < 0.05). While 11 and 13 ‰ salinity and 30 °C thermal stress had no effect, 1 g kg?1 of chitosan (P < 0.05) showed highest survival rate (70 %) in 34 °C thermal stress. The results showed that chitosan in the diet of the Caspian kutum fingerlings could improve feed conversion ratio, the nonspecific defense mechanisms and resistance to some of the environmental stresses.  相似文献   

17.
Three experiments were carried out to separately investigate the effects of stocking density (1.0, 2.0, 4.0 and 8.0 larvae ml?1), diet (Isochrysis zhanjiangensis, Chlorella spp., Nannochloropsis oculata, 50 % I. zhanjiangensis/50 % Chlorella spp. and 50 % I. zhanjiangensis/50 % N. oculata), and water exchange (25 % once every other day and 25, 50 and 100 % once daily) on growth and survival of pearl oyster Pinctada maxima larvae. Results showed that there existed significant effects of stocking density, diet, and water exchange on the growth of pearl oyster larvae (P < 0.05). Larval survival was significantly affected by stocking density and diet (P < 0.05), but not by water exchange (P > 0.05). Larval growth decreased significantly with increasing stocking density (P < 0.05). A density of 1.0–4.0 larvae ml?1 was optimal for larval growth of pearl oyster. Chlorella spp. and N. oculata could replace 50 % of I. zhanjiangensis as a food source for the pearl oyster larvae without affecting growth and survival. A water exchange of 25 % once daily provided optimum larval growth and survival.  相似文献   

18.
CYP19 is considered as an important factor affecting reproductive endocrinology in many fishes, and plays an important role in ovarian development, reproductive function and sexual differentiation. In this study, three single nucleotide polymorphisms (SNPs) within CDS of the CYP19a gene were tested and the associations between their genotypes and four reproductive traits were analyzed in 65 Japanese flounder individuals with Polymerase chain reaction and Single-stranded conformational polymorphism (PCR–SSCP). Results indicated that a SNP in the exon7 of CYP19a gene, SNP2, was significantly associated with 17β-estradiol (E2) (P < 0.05) and gonadosomatic index (GSI) (P < 0.05). Individuals with genotype AB of SNP2 had significantly higher serum E2 levels (P < 0.05) and GSI (P < 0.05) than those of genotype AA or BB. In addition, there was significant association between one diplotype based on three SNPs and reproductive trait. The genetic effects for both serum E2 of diplotype D9 and GSI of diplotype D1 were respectively much higher than those of other diplotypes (P < 0.05). The evidence of the associations between genetic variants with serum E2 and GSI may help explain effects of CYP19a gene in reproductive endocrinology of Japanese flounder.  相似文献   

19.
To assess the growth-promoting potential of three medicinal herbs, Alteranthera sessilis, Eclipta alba and Cissus quadrangularis, a 90-day feeding trial was conducted on Macrobrachium rosenbergii post-larvae (PL) fed with these herb-incorporated feeds. The growth parameters (survival rate, weight gain, specific growth rate and protein efficiency ratio) were significantly (P < 0.05) higher in experimental-diets-fed PL when compared with control. These herbs have acted as appetizer and significantly enhanced the activities of digestive enzymes (protease, amylase and lipase). This in turn significantly (P < 0.05) influenced the parameters of energy utilization (feeding rate, absorption rate, conversion rate, metabolic rate and NH3 excretion rate), which ultimately reflected on significant (P < 0.05) increases in concentrations of biochemical constituents (total protein, amino acid, carbohydrate and lipid, and essential amino acids and unsaturated fatty acids). Therefore, it was believed that synthesis of protein was activated due to the active principles of these herbs and resulted in growth promotion. In this study, the higher (P < 0.05) minerals (Na+ and K+) recorded indicate the fact that their balance was maintained. Similarly, the non-enzymatic antioxidants (vitamin-C and -E) status were also improved significantly (P < 0.05) due to herbal incorporation, which provide additional protection. Further, the haemocytes count and population was also found to be higher (P < 0.05), which ensures prevalence of good host-defence mechanisms in herb-incorporated-feeds-fed PL. Among three herbs tested, C. quadrangularis-incorporated-feed-fed PL showed the best survival, growth and protection as well as production followed by E. alba and A. sessilis. Therefore, these herbs can be incorporated in artificial feed formulations for sustainable development of Macrobrachium culture.  相似文献   

20.
Labeo rohita (139.92 ± 0.76 mm/24.33 ± 0.45 g) was reared for 92 days in floating square cages (10 m2 area, 1.5 m height) in a pond (2 ha) at six stocking densities (5, 7.5, 10, 15, 20 and 25 fish m?2) each with 3 replicates. Fish were fed daily once in the morning with rice polish and groundnut oil cake (1:1) in dough form at 3 % of the total body weight. Survival ranged from 96 to 100 % in different stocking densities. Final average body weight, average body weight gain, mean daily body weight gain and SGR decreased (P < 0.05) with increasing stocking density. Conversely, final biomass, biomass gain and FCR increased (P < 0.05) with increasing stocking density. The highest growth rate of fish could be achieved up to 60 days at 5 fish m?2 and 92 days at other densities. The reduced growth rate at 10–25 fish m?2 for 60 days of culture indicated that stress is related to size and density of the fish, suggesting that utmost care is required to reduce the stress at high densities. Maximum production and profit was observed at the highest stocking density. Non-lethal levels of water and soil qualities at different sites (cage premises, and 20 and 200 m away from cage area) suggested that cage aquaculture could be done safely covering 0.9 % of pond area. Production of advanced fingerlings in cages was found a viable alternative to their culture in pond.  相似文献   

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