The catfish Ompok bimaculatus (butter catfish) has recently gained importance as an aquaculture candidate species because of its delicious taste, higher nutritional value and market demand. A significant problem in butter catfish aquaculture is its inability to voluntarily spawn in captivity. This experiment was conducted to study the impact of photoperiod on the voluntary spawning of O. bimaculatus in the pre‐spawning season (April) in captivity. A total of 80 broodfish were equally distributed (n = 20; F = 10 and M = 10) into four photoperiod treatments: natural condition (control), 12:12 light:dark (L:D), 15L:9D and 9L:15D were stocked in rectangular tanks, and the experiment was carried out for 45 days. Light intensity was maintained at 1000 lx throughout the study for all treatments, except the control. The fish were fed a commercial diet (40% crude protein and 6% crude lipid) at a rate of 3% of body weight, twice a day, for 45 days. Ovasis™ was used for hormone induction to study induced breeding. Broodfish reared under natural photoperiod (control) did not respond to voluntary captive spawning. A complete voluntary captive spawning response was observed in the 12L:12D broodfish, and partial success was observed in the 15L:9D and 9L:15D broodfish. The fertilization rate, hatching rate and survival were significantly (p < 0.05) higher in the 12L:12D broodfish group than those in the broodfish group. Hence, the photoperiod regime of 12L:12D with 1000 lx light intensity would be ideal for voluntary captive spawning and can be elected for maximum seed production in the pre‐spawning season. The present study showed that photoperiod manipulation and fixed light intensity stimulate advanced gonadal maturation and voluntary captive spawning of butter catfish, which can help seed production throughout the year.
Aquaculture is the fast-growing agricultural sector and has the ability to meet the growing demand for protein nutritional security for future population. In future aquaculture is going to be the major source of fish proteins as capture fisheries reached at its maximum. However, several challenges need to overcome such as lack of genetically improved strains/varieties, lack of species-specific feed/functional feed, round the year availability of quality fish seed, pollution of ecosystems and increased frequencies of disease occurrence etc. In recent years, the continuous development of high throughput sequencing technology has revolutionized the biological sciences and provided necessary tools. Application of 'omics' in aquaculture research have been successfully used to resolve several productive and reproductive issues and thus ensure its sustainability and profitability. To date, high quality draft genomes of over fifty fish species have been generated and successfully used to develop large number of single nucleotide polymorphism markers (SNPs), marker panels and other genomic resources etc in several aquaculture species. Similarly, transcriptome profiling and miRNAs analysis have been used in aquaculture research to identify key transcripts and expression analysis of candidate genes/miRNAs involved in reproduction, immunity, growth, development, stress toxicology and disease. Metagenome analysis emerged as a promising scientific tool to analyze the complex genomes contained within microbial communities. Meta-genomics has been successfully used in the aquaculture sector to identify novel and potential pathogens, antibiotic resistance genes, microbial roles in microcosms, microbial communities forming biofloc, probiotics etc. In the current review, we discussed application of high-throughput technologies (NGS) in the aquaculture sector.
Simple sequence repeat markers also known as microsatellite markers have been used to answer several biological questions. Cultrinae is one of the thirteen subfamilies of family Cyprinidae encompassing several economically important freshwater aquaculture species. With the advancement of the next generation sequencing technologies and simultaneous development of bioinformatics tools it is now possible to decipher the whole genome sequences of several model and non-model species. The whole genome sequence of three Cultrinae species is available in the public database. In the present study, we identified and compared simple sequence repeat markers in three Cultrinae species, i.e. Anabarilius grahami, Megalobrama amblycephala and Culter alburnus. The genome size of A. graham, C. alburnus and M. amblycephala was found to be 0.9 GB, 1.02 GB and 1.08 GB, respectively. Evaluation of completeness of the genomes using BUSCO revealed 96.8%, 96.6% and 94.9% completeness, respectively. In total, 398,473, 522,850 and 579,378 perfect SSR repeats with 1–6 bp nucleotide motifs were identified encompassing 8,391,632, 11,457,461 and 12,860,863 repeat bases, respectively in A. graham, C. alburnus and M. amblycephala. The simple sequence repeat motifs cover 0.85%, 1.13% and 1.18% of the present A. graham, C. alburnus and M. amblycephala draft genome. The frequency and density of SSR repeat motifs in the three Cultrinae genomes were 401.73, 513.75 and 532.57 and 8460.27, 11,258.12 and 11,821.74, respectively. The mono, di, tri, tetra, penta and hexa nucleotides repeat in A. graham, C. alburnus and M. amblycephala genomes were found to be 119,554, 195,336 and 240,710, 134,985, 157,238 and 178,370, 39,066, 51,112 and 51,684, 87,395, 99,004 and 88,985, 14,323, 18,646 and 17,772, 3150, 1514 and 1857, respectively. Mononucleotide repeats were the most frequent repeats and hexanucleotide repeats were least frequent repeat motifs. Among the mononucleotide A, among dinucleotide AT and AC, among trinucleotide AAT, among tetranucleotide AAAT and AGAT, among penta-nucleotide AAAAT, AATAT and AAGTG and among hexanucleotides AAAAAT, AACCCT and AAATGT were the most frequent repeat motifs. The repeat motifs in all the genomes were A + T rich. The information generated in the present study may facilitate research on role of simple sequence repeat motifs in genome organization and gene regulation, etc. in the above species.
The 19-fold increase in fish production in the last seven decades in India, i.e., from 0.75 million metric tonnes (MMT) in 1950–51 to the present level of 14.2 MMT amply justifies the importance of the fisheries sector not only providing the protein and nutritional security of the masses but also its increasing contribution to the national economy. When the production from capture fisheries was stagnating, aquaculture has become a saviour for enhancing the targeted growth in fish production. From the meagre 0.37 MMT in 1980 to over 9.0 MMT at present, a 25-fold increase in aquaculture production in just four decades has placed the country as a forerunner on the global front. The freshwater sector that shares over 90% of total aquaculture production is largely contributed by carps and meeting the demand of the domestic front. The coastal ecosystem is contributing a significant share of the 8.2 MMT of freshwater aquaculture production with Andhra Pradesh, West Bengal, and Odisha being the major producers. Increasing production of diversified freshwater species including those of exotic striped catfish, pacu, and tilapia again is largely contributed by Andhra Pradesh. While carp polyculture and monoculture of exotic striped catfish have been steering the freshwater aquaculture production, a range of other non-conventional culture systems, viz., sewage-fed fish culture, integrated farming systems, cage and pen culture, and the new technologies like RAS and biofloc systems has made freshwater aquaculture an increasingly growing activity across the country. As a backyard avenue, ornamental fish breeding and rearing have been proved to be highly viable activity especially for the areas adjoining cities/towns due to their assured market. The self-sufficiency in quality carp seed production through large-scale adoption of the technologies of controlled breeding, hatchery production, and seed rearing has been ensuring guaranteed seed supply and practically guiding the aquaculture development in the country. Success in the development of breeding and seed production technologies of over 40 cultivable freshwater finfish and prawn species is leading farmers to adopt new species for culture diversification. In this endeavour, it is the coastal ecosystem led by the state of West Bengal contributing the bulk of the seed production in the country. Availability of a host of farmers’-friendly technologies with varied production potential, execution of different technology transfer programmes through the institutional frameworks, increasing private investments, good temperature regimes, productive soil, good water availability, and above all, increasing demand for fish have been instrumental for the accelerated growth of freshwater aquaculture in the coastal eco-regions. The fisheries sector in India has been able to demonstrate a phenomenal average annual growth rate of 10.88% to the national GVA in the last five years. Freshwater aquaculture has been the principal contributor to this growth, and it is expected that the sector would continue to take the lead in meeting the projected production target of 22.0 million tonnes of fish by 2025 and also contributing to increased employment generation.
Climate vulnerability and induced changes in physico-chemical properties of aquatic environment can bring impairment in metabolism, physiology and reproduction in teleost. Variation in environmental stimuli mainly acts on reproduction by interfering with steroidogenesis, gametogenesis and embryogenesis. The control on reproductive function in captivity is essential for the sustainability of aquaculture production. There are more than 3,000 teleost species across the globe having commercial importance; however, adequate quality and quantity of seed production have been the biggest bottleneck. Probiotics are widely used in aquaculture as a growth promoter, stress tolerance, pathogen inhibition, nutrient digestibility and metabolism, reproductive performance and gamete quality. As the gut microbiota exerts various effects on the intestinal milieu which influences distant organs and pathways, therefore it is considered to be a full-fledged endocrine organ. Researches on Gut-Brain-Gonad axis (GBG axis) and its importance on physiology and reproduction have already been highlighted for higher mammals; however, the study on fish physiology and reproduction is limited. While looking into the paucity of information, we have attempted to review the present status of microbiome and its interaction between the brain and gut. This review will address a process of the microbiome physiological mechanism involved in fish reproduction. The gut microbiota influences the BPG axis through a wide variety of compounds, including neuropeptides, neurotransmitter homologs and transmitters. Currently, research is being conducted to determine the precise process by which gut microbial composition influences brain function in fish. The gut-brain bidirectional interaction can influence brain biochemistry such as GABA, serotonin and tryptophan metabolites which play significant roles in CNS regulation. This review summarizes the fact, how microbes from gut, skin and other parts of the body influence fish reproduction through the Gut-Brain-Gonad axis.
Background The small non-coding microRNAs play a vital role in post-transcriptional gene regulation associated with different physiological events such as metabolism, stress, etc. The freshwater catfish, Clarias magur, can grow within hyper ammonia containing stagnant water bodies and/or muddy substratum. We intended to identify organ-specific miRNAs associated with ammonia stress management. Methods and results The miRNA-libraries were generated from QC passed total RNA extracted from liver, muscle, and kidney of ammonia-treated (exposed to 25 mM NH4Cl for 14 days) and untreated catfish. The libraries were validated using High sensitivity D1000 Screen tape. The trimmed quality-filtered reads for control and treated samples of kidney were 19,406,210; 14,904,423; for liver 15,467,727; 18,582,072; and for muscle 25,081,345; 19,782,182 respectively. Total 120 known and 150 novel differentially expressed miRNAs were identified, out of which miR-200, miR-217, miR-122, miR-133, miR-145, miR-221, miR-19, miR-138, miR-34, and miR-184 were predicted to be involved in the metabolism of nitrogen. The key miRNAs targeted several genes associated with urea synthesis like Glutaminase 2, Argininosuccinate lyase, Glutamate dehydrogenase 1, Alanine aminotransferase 2-like, Aspartate aminotransferase, cytoplasmic-like, Glutamate ionotropic receptor NMDA type subunit 2A, etc. Conclusions This is the first report of miRNAs, which serve as a vital resource for regulating nitrogen metabolism in freshwater catfish, C. magur. The data will be resourceful for further evaluating the regulatory role of miRNAs in fishes, which grow and reproduce very well in hazardous ammonia-contaminated water bodies.
Aquaculture is a dynamic system that uses water resources to generate profit. Its quantum leap to overcome the threat of stress impacts and accelerate its voyage towards precision aqua-farming is extremely acceptable with the addition of fresh, green materials. Iron nanoparticles can be chosen as a next-generation material among many additions. Iron is found in practically every living entity, including fish, and plays an important part in a variety of biological processes. Besides significant contribution as micronutrient, it contributes to the formation of hemoglobin and myoglobin, enzymes like catalase, iron-responsive element-binding protein (IRE-BP), lipoxygenases, and functions as cofactors in metalloproteins, like ferritin and rubredoxin, etc. Nanoscale form of iron can be synthesized through Physico-chemical and biological processes and appears as a versatile molecule for upgrading the pace of aquaculture. Nano-iron provides active micronutrient spearheading the function of Fe–S Cluster synthesis, increased storage of ferritin, and elevated heme synthesis. Iron nanoparticles also function as immunomodulators, exhibit anti-microbial activities against major fish pathogens, and stimulate reproductive potency in fish. Its widespread application to remediate all categories of aquatic pollutants can help nurture fish in environmentally challenging conditions. Furthermore, unique drug delivery devices for delivering and tracking medications in fish systems can be devised. The nano-iron enabled biosensor can be used to detect pollutants/pathogens in extremely small concentrations in the aquatic medium. Toxicity assays in the fish system denote the dose-dependent application of this potential molecule. Hence, iron nanoparticles can be applied commercially for the advancement of stress-resilient aquaculture.
Background: The emerging viral pandemic worldwide is associated with a novel coronavirus, SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). This virus is said to emerge from its epidemic center in Wuhan, China, in 2019. Coronaviruses (CoVs) are single-stranded, giant, enveloped RNA viruses that come under the family of coronaviridae and order Nidovirales which are the crucial pathogens for humans and other vertebrates. Main body: Coronaviruses are divided into several subfamilies and genera based on the genomic structure and phylogenetic relationship. The name corona is raised due to the presence of spike protein on the envelope of the virus. The structural and genomic study revealed that the total genome size of SARS-CoV-2 is from 29.8 kb to 29.9 kb. The spike protein (S) is a glycoprotein that attaches to the receptor of host cells for entry into the host cell, followed by the attachment of virus RNA to the host ribosome for translation. The phylogenetic analysis of SARS-CoV-2 revealed the similarity (75-88%) with bat SARS-like coronavirus. Conclusion: The sign and symptoms of novel severe acute respiratory syndrome coronavirus 2 are also discussed in this paper. The worldwide outbreak and prevention from severe acute respiratory syndrome coronavirus 2 are overviewed in the present article. The latest variant of coronavirus and the status of vaccines are also overviewed in the present article.
Hilsa, Tenualosa ilisha , is a commercially important high valued food fish in South Asian countries. Recently, much attention of this species has been paid for its conservation through captive culture due to its declining trend of population. Insufficient number of Hilsa seeds is the major bottleneck for its captive culture. This study aimed at developing a larval rearing protocol through co-feeding combined with planktons and formulated diet to facilitate its seed production that can support its culture. Hilsa larvae (3.67 ± 0.21mm/0.36 ± 0.00mg) were reared for 80 days in fiberglass-reinforced plastic tanks at 250 nos m − 3 in triplicates. They were fed with three different formulated diets as FI, F2, and F3 having 35.5%, 40.5%, and 45.3% crude protein (CP), along with Chlorella sp., Brachionus sp. and mixed zooplanktons as a co-feeding strategy. F2 diet feeding larvae showed significantly (P < 0.05) higher survival (88.5%), final body-length (36.21mm), final body-weight (0.43g), daily body-length gain (0.41mm), daily body-weight gain (0.01g) and SGR (8.96% day − 1 ) than that of other two diets: survival, F169.33% & F3 40.33%; final body-length, F1 32.1mm & F3 30.03mm; final body-weight, F1 0.31g & F3 0.2g; daily body-length gain, F1 0.36 mm & F3 0.33mm; daily body-weight gain, F1 0.004g & F3 0.003g; and SGR, F1 8.55% day − 1 & F3 8.02% day − 1 , respectively). Hilsa larval growth and survival achieved optimal while fed F2 diet with 40.5% dietary CP along with plankton as co-feeding. The finding may facilitate Hilsa culture in captivity through co-feeding strategy.
Climate change and temperature variations are of paramount importance to aquaculture. Here, we investigated the thermal stress response of five life stages of tilapia viz. spawn, fry, fingerling, juveniles and adults exposed to different temperatures (28°C to 40°C). Stress response was assessed in terms of survival/mortality, thermal shock, changes in hematology, histopathology of liver and gonad. The spawn, fry and fingerlings died within 1 to 39 min at 40°C due to thermal shock. Thermal acclimation was observed in these stages till 34°C. Beyond 34°C, low feed intake and susceptibility were marked. Significant increments in the hematological parameters were noticed when the water temperature elevated from 28°C to 32°C and thereafter deteriorated. Hematological parameters, gonadosomatic index (GSI), digestive somatic index (DSI) and hepatosomatic index (HSI) showed ideal conditions at temperatures between 28°C to 30°C. However, a marked change in the liver and gonad histoarchitecture and decreased organ somatic indices of adult tilapia were also noticed in response to elevated temperatures. This study suggests that the developmental stages of tilapia are highly susceptible to thermal shock and a gradual temperature rise helped them acclimate to 34°C. Further temperature rise may adversely affect tilapia aquaculture.
A 60 days growth trial was conducted with fry of Hypselobarbus pulchellus for evaluating the effect of incorporation of two aquatic plants Azolla microphylla and Vallisneria spiralis at 30, 60 and 90% levels in the diet on growth and survival. The fry (average weight 23.07 ± 0.96 mg and average length 1.57 ± 0.24 cm) were stocked at 12 numbers per tank and fed to satiation with one of the experimental diets (three diets each with azolla and vallisneria) or a control diet. Water quality parameters analysed at fortnightly intervals did not show significant difference between treatments (p > .05). The mean final weight of fish reduced in groups fed diets with azolla and vallisneria incorporated beyond 60% and 30% respectively (p < .05). While the mean final length of fish fed azolla diets did not differ among the treatments, it gradually reduced in groups fed diets with increasing levels of vallisneria incorporation (p > .05). The condition factor and survival did not vary between treatments (p > .05). The study indicates the possible incorporation of azolla up to 60% and vallisneria up to 30% as feed ingredients in the diet for H. pulchellus during fingerling raising.
Globally, incidences of fish diseases caused by parasites have been on a rise, especially in intensive aquaculture practise, leading to considerable economic losses. The traditional control measures and therapeutics used to manage parasitic infections are associated with numerous limitations as well as risks. Vaccines have emerged as an effective means for control of pathogens; the use of vaccines for bacterial fish diseases has successfully cut down the use of antibiotics in aquaculture. However, development of vaccines for parasitic diseases of fish has seen limited success with availability of only commercial vaccine against sea lice. Nevertheless, significant strides have been made in understanding host-parasite interactions, which provides researchers with the arsenal of information required for identification of vaccine candidates and their development. In this review, we discuss protective responses reported in fish against major group of parasites and various efforts made in the field of vaccine development for important parasite groups of both marine and freshwater fish.
High density fingerling rearing of pengba, Osteobrama belangeri in biofloc system was carried out for 45 days with wheat flour and molasses as two carbon sources to maintain C/N ratio of 15:1. Effect of biofloc was evaluated in terms of water quality changes, fish growth performance, digestive enzyme activities, non‐specific immune system and antioxidants enzyme activities. Use of the two carbon sources ensured prevalence of better growing environment, higher digestive and antioxidant enzymatic activities, ultimately leading to higher fish growth, as compared to control. Further between the two carbon sources, use of wheat flour caused significant increase in the activities of digestive enzymes, amylase and total protease (p < .05); antioxidant enzymes such as SOD and catalase; increase in serum total protein, albumin and globulin, as compared to molasses, ultimately leading to higher growth. However, non‐specific immune parameters such as respiratory burst activity in blood, lysozyme activity, and myeloperoxidase activity in serum were higher (p < .05) in fish reared with molasses. Such result while indicated benefits of additional carbon source, it also revealed wheat flour to be a better source for carbon supplementation than molasses in biofloc system during the high‐density fingerling rearing of O. belangeri.
The present work assessed the seasonal changes in germ cells (GC) and the maturation of rohu, Labeo rohita and tilapia, Oreochromis niloticus. Here, we showed two species representing two diverse types of spawning behavior, having two distinct GC proliferation and spawning patterns. During July, a single peak spawning season for rohu was recorded with the highest GSI (female: 19.5±1.29 and male 4.2±0.24), which is the peak monsoon time in Eastern India. However, two peak spawning seasons were marked in tilapia during the pre-monsoon (April) and post-monsoon (October) period with GSI values of male: 0.9±0.21, female: 3.9±1.32 and male: 1.1±0.3, female: 4.4±1.1 respectively. Gonadal histology in synchrony with GSI provides insights into the effects of various seasonal climate changes on the reproductive status of fish. Further, GC ultra-structure revealed various development stages in rohu and tilapia in different seasons using a scanning electron microscope. Here, comparative models were proposed for GC proliferation and maturation during different parts of the year in rohu and tilapia that may be used to plan breeding programs and hatchery management of these two species.
The use of chemicals, biologicals and veterinary medicinal products (VMPs) helps in healthy and sustainable fish production. Information on the use of these products is essential for assessing farming practices, potential human health and environmental risks. A questionnaire‐based nationwide survey covering aquaculture farms (n = 2936) producing carps, tilapia, pangasius and rainbow trout in freshwater and shrimp in brackishwater estimated the use of 52 different types of inputs which included disinfectants (597 g t−1), probiotics (2.28 kg t−1), environmental modifiers (22.82 kg t−1), nutritional supplements (1.96 kg t−1), natural anti‐infective agents (293 g t−1), herbicide and piscicides (844 g t−1), antibiotics (2 mg PCU−1), antifungal (4 mg PCU−1), and antiparasitic (14 mg PCU−1) agents. The bulk of these inputs was used for soil and water quality improvement and had low environmental and human safety concerns. The multivariate analysis revealed significant variation in the frequency and quantity of compounds use among farm groups. Redundancy analysis revealed a significant association between the number of products used and stocking density. The survey also showed a considerable influence of education and farming experience on the usage pattern of aquaculture inputs. Results of the study indicated greater reliance of farmers on the use of disinfectants for biosecurity, nutritional supplements for enhanced growth and environmental modifiers for maintaining soil and water quality in culture systems. Though there was no use of restricted antibiotics and antiparasitic agents, the development and implementation of standard regulatory guidelines are essential for safe and effective use of inputs for sustainable aquaculture.
Soil, amongst the natural resources is of superlative important, nurturing innumerable microbes essential for maintaining soil fertility, crop protection vis-à-vis crop productivity. Productivity of crop mostly decreases due to disease caused by wide range of phytopathogens. The use of bioantagonist as biocontrol agents has been of utmost importance to combat phytopathogens instead of agrochemicals/pesticides. Biocontrol of crop phytopathogens comprehended curtailment in pathogenic inoculum concentration or restricted infectivity. Using few bacteria is an alternative option against rice phytopathogens as well as agrochemicals for an affirmative socio-ecological impact. Species of soil Bacillus sp. offers advantages over others in biocontrol of rice pathogens via production of array of broad-spectrum antibiotics and resistant endospores. Advancement in molecular biology revealed the molecular pathways and mechanisms involved in antagonism of Bacillus sp. aiding disease reduction, remediation, improvement and wider use of biocontrol agents. The pathway of biocontrol prospective involves parasitism, competition for nutrients and space, antibiosis, induced disease resistance and other cellular interactions. In the present chapter an attempt has been made to implement Bacillus sp. as a biocontrol agent to combat rice bacterial pathogens including its in depth physiology, mode of action, genetics, limitations and enhanced applications for disease management.
Genetic selection programmes in gilthead seabream mainly focus on traits related to growth, disease resistance, skeletal anomalies, or fillet quality. However, the effect of selection for growth on the reproductive performance of seabream broodstock has not received much attention. The present study aimed to determine the effect of selection for growth traits, high (HG) or low (LG) growth, and broodstock feeding with fish oil (FO diet) or rapeseed oil (RO diet) as main lipid sources, on reproductive performance of gilthead seabream. For the first part of the spawning season (Phase I) HG and LG broodstock were fed a commercial diet and the HG broodstock produced a higher number of larvae and higher viable eggs, hatching and larval survival rates than LG broodstock, affecting egg fatty acid profiles. For the second part of the study (Phase II) broodstock were fed one of the two diets containing FO or RO. Fecundity in terms of viable eggs, hatchlings, and larvae produced, as well as fertilization rates, were improved in HG broodstock. Some fatty acids such as 18:0, 20:2n-6, 20:3n-3 or EPA/ARA were also affected by the growth selection. According to the two-way ANOVA analysis, feeding the RO diet did not significantly affect fecundity parameters, but slightly reduced fertilization and hatching rates in HG broodstock. Nevertheless, HG broodstock showed better spawning quality parameters than LG broodstock, even when they were fed the RO diet. Egg fatty acid profiles reflected diet composition, although DHA contents were not affected. In conclusion, broodstock selected for high growth had a positive effect on broodstock performance, and FO replacement by RO did not markedly affect reproduction providing that fatty acid contents were sufficient to fulfil the essential fatty acid requirements of gilthead seabream broodstock.
The dietary protein requirement of the peninsular carp, Hypselobarbus pulchellus was investigated through a feeding trial conducted in aerated plastic tanks (50 L) with five isocaloric diets formulated to contain crude protein levels ranging from 20 to 40% (CP20, CP25, CP30, CP35 and CP40) using pure ingredients with casein and gelatin as the protein sources. Fingerlings (mean wt. 4.71 g) of H. pulchellus were fed at 5% of the biomass for a period of 60 days. The growth parameters increased with dietary protein level up to 35% followed by a decrease with CP40 diet. Lowest (p < 0.05) food conversion ratio was recorded with 35% protein diet. Protein efficiency ratio values were inversely proportional to the dietary protein level. The condition factor ranged from 0.94 to1.07 with no difference among the treatments. No difference (p > 0.05) was recorded in fish survival. Proximate composition analysis of fish carcass indicated no difference (p > 0.05) in moisture, fat and ash contents. Crude protein content on the other hand, showed values increasing with dietary protein level up to 35%, beyond which (CP40), it stagnated. Apparent digestibility coefficient for protein also increased gradually with the dietary protein level with a peak under CP35 and then decreased at CP40. Fat digestibility values, on the other hand, were similar (p > 0.05) for all diets. Analysis of the activity of digestive enzymes indicated highest activity of trypsin and total protease in both intestine and hepatopancreas of fish fed 35% crude protein diet. The second‐ order polynomial regression analysis for weight gain rate and specific growth rate indicated a dietary protein requirement between 31.80 and 32.76% for the fingerlings of H. pulchellus. This information on protein requirement would be useful in developing species specific feed for this critically endangered peninsular carp.
Brewer’s-spent-yeast (BSY) is among the most voluminous byproducts generated in brewery industry that adds to the waste; however, smart utilization of BSY could lead to edible biomass production besides waste management. To utilize it for biomass production, it is being used in fish feeds; however, its effect on the fish physiology has been scantily studied. The present study investigated the proteomic changes in muscle tissues of carp Labeo rohita fed with BSY-based diet, to understand its impact on muscle physiology and biomass. Six feeds were prepared with different grades of BSY (0, 20, 30, 40, 50, 100% replacement of fishmeal with BSY) and fishes were fed for 90 days. Highest weight gain%, feed conversion efficiency, specific growth rate% were observed in 30% BSY-replaced group and this group was considered for the proteomic study. Comparative shotgun proteomic analysis was carried out by LC-MS/MS and data generated have been deposited in ProteomeXchange Consortium with dataset identifier PXD020093. A total of 62 proteins showed differential abundance; 29 increased and 33 decreased in the 30%BSY replaced group. Pathway analysis using IPA and Panther tools revealed that the proteins tyrosine protein kinase, PDGFα, PKRCB and Collagen promote muscle growth by inducing the PI3K-AKT pathway. Conversely, the proteins Serine/threonine-protein phosphatase, Phosphatidylinositol 3,4,5-trisphosphate5-phosphatase 2A, Ras-specific guanine- nucleotide-releasing factor inhibit muscle growth indicating that 30% BSY replaced feed promote muscle growth in a highly controlled manner. Findings suggest that BSY could be recycled for carp feed production in large-scale thereby leading to resource conservation, reducing environmental effects.
The present study explores agrobiodiversity in the changing shifting cultivation landscapes (SCL) in India’s North East, a region that accounts for 83% of the area under SCL in India and also encompasses the Indo-Burma biodiversity hotspot. Based on a survey of 481 households across 52 villages in six states in India to quantify agrobiodiversity using a large dataset, the study also captures the socio-ecological dimensions of, and potential threats to, agrobiodiversity conservation. The careful assessment documented 55 crop species and6 breeds of livestock, both with numerous landraces, and many wild edible plants. This available biodiversity within the SCL plays a central role in delivering ecosystem goods and services that sustain the well-being of the inhabitants of the landscape. However, North East India’s SCLs are steadily moving towards cash crops and also towards increasingly shorter fallow periods. These findings are clarion call to preserve landraces – preserved for decades if not centuries as part of the traditional agroforestry systems practised by the indigenous peoples – that may one day prove invaluable in building resilience by ensuring integrated landscape planning for sustainable development. Above all, the study results may be useful to Landscape Stewardship-Integrating landscape values into agricultural and rural development policies.
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