Effects of carotenoid supplementation on colour, growth and physiological function of the endemic dwarf chameleon fish (Badis badis).

The global ornamental fish trade is expanding in response to increased demand for indigenous fish on the global market, while exogenous carotenoids can improve colouration. The 60-day trial investigated the effect of carotenoid supplementation, via Artemia, on colouration, growth and immunophysiology of Badis badis (dwarf chameleon fish). Carotenoid was enriched at 40 ppm (T1), 80 ppm (T2) and 120 ppm (T3) and compared with controls, C1 (unenriched) and C2 (oil-enriched). Fish larvae (average weight 0.12 g) were fed enriched-unenriched Artemia in triplicates (5 × 3) in aquarium tanks (15 L). C1 and T2 had better skin colour (lightness and whiteness) in the posterolateral and caudal fins respectively. The value of redness (a*) in the anterolateral region was higher in T2 and T3 (p < 0.05). The anterolateral red index was higher (p < 0.05) in T2 and T3, whereas in the posterolateral and caudal fins, T1 and T2 were higher (p < 0.05). Compared to C1 and C2, the hue angle in carotenoid groups was found to be low (p < 0.05). No significant change in the growth performance was noticed (p > 0.05). Immune scores such as lysozyme and alkaline protease were highest in T3 (p < 0.05), whereas protease activity was highest in T2 (80 ppm). Stress biomarkers, viz., superoxide dismutase, catalase and malondialdehyde were low in groups fed enriched Artemia (p < 0.05). The integrated biomarker response means and star plot area were lower in the enriched groups (T1-T3), while T2 was the lowest. Overall findings reveal that dietary carotenoid improves the colouration and immune status, but fail to promote growth. Furthermore, 80 ppm enrichment dose improves the overall performance. The findings can help fish keepers improve fish colour and health status through carotenoid supplementation.

The current state of research and potential applications of insects for resource recovery and aquaculture feed.

Concerns about fishmeal use and its ecological footprints must be addressed for the aquaculture industry to move on as a sustainable food production sector. Through recent research outcomes, the insect-based meals in fish diets have promise and harnessed promises for commercial applications. In this midst, the efficiency of the selected insects in valorizing biological waste, as well as the nutritional profile of the harvested insects for use in fish diets, will be the driving forces behind such an approach. More extensive research has been published on the suitability of the waste substrate, the nutritional profiling of the meals, the level of substitution, the effects on growth, the immune physiology, and the flesh quality of the animals. Previously, there are only a few reviews available in insect protein applications in aqua feed that focused particularly on the nutritional quality and substitution levels. Considering the dearth of available work, the goal of this review is to provide a more comprehensive account of the resource recovery potential of insects and its derivatives, with a special emphasis on quality as determined by substrate used and processing techniques. Suggestions and policy implications for a sustainable approach to achieving a circular bio-economy of insect farming and its application in aquaculture are discussed for progression and advancement of the existing state of the art.

Stocking density affects immune and stress-related gene expression of Butter catfish (Ompok bimaculatus) fry in biofloc landscapes.

Scientific research into fish wellness is critical, and the concerns about crowding-related stress due to increased stocking density are inevitable. Taking this into consideration, the study defines the physiological signature of Ompok bimaculatus (Butter catfish) in a biofloc system when subjected to varying levels of stocking density. Fish (mean weight = 1.21 g ± 0.08, n = 600) were randomly stocked in 40-L glass aquaria at stocking densities of 0.5 g/L (T1), 1 g/L (T2), 1.5 g/L (T3), and 2 g/L (T4) and fed a 35% protein diet. After the 90-day trial, the physio-biochemical, molecular, and tissue-level changes were assessed. An integrated biomarker response (IBR) analysis for the key stress indicators aided us in better understanding them. There was a significant difference in blood count between T1 and T4 (total erythrocyte count, hemoglobin, and packed cell volume). T1 had higher levels of globulin and total plasma protein, but T2 had higher levels of albumin. Only in T1 did the respiratory burst and lysozyme activity appear to be higher (p < 0.05). Increased stocking densities had a significant impact on the liver function enzymes, GOT and GPT (p < 0.05). In comparison to lower densities (T1 & T2), higher stocking density (T3 & T4) was found to raise glucose and cortisol levels (p < 0.05). Antioxidant enzymes such as catalase, glutathione-S-transferase, and malondialdehyde were found to be more pronounced in lower density tissues (T1). Furthermore, the IBR plots show that lower densities have better health than higher densities. At higher stocking densities, mRNA expression of HSP70, IL-1, and IL-20 increased (p < 0.05) in kidney and liver tissues. The Nrf-2 and Tlr-9 genes were also upregulated. Also, when stocking density was increased, tissue-level histo-architectural changes were more pronounced than when stocking density was kept low. The findings of this study show that the welfare of Butter catfish cultured at high density in biofloc systems suffers from severe stress, and therefore draw more attention to the development of a species-specific standard rearing methodology in the pursuit of a profitable aqua-farming enterprise.

Diverse uses of valuable seafood processing industry waste for sustainability: a review.

Seafoods are rich in untapped bioactive compounds that have the potential to provide novel ingredients for the development of commercial functional foods and pharmaceuticals. Unfortunately, a large portion of waste or discards is generated in commercial processing setups (50-80%), which is wasted or underutilized. These by-products are a rich source of novel and valuable biomolecules, including bioactive peptides, collagen and gelatin, oligosaccharides, fatty acids, enzymes, calcium, water-soluble minerals, vitamins, carotenoids, chitin, chitosan and biopolymers. These fish components may be used in the food, cosmetic, pharmaceutical, environmental, biomedical and other industries. Furthermore, they provide a viable source for the production of biofuels. As a result, the current review emphasizes the importance of effective by-product and discard reduction techniques that can provide practical and profitable solutions. Recognizing this, many initiatives have been initiated to effectively use them and generate income for the long-term sustainability of the environment and economic framework of the processing industry. This comprehensive review summarizes the current state of the art in the sustainable valorisation of seafood by-products for human consumption. The review can generate a better understanding of the techniques for seafood waste valorisation to accelerate the sector while providing significant benefits.

Blue agave inulin-soluble dietary fiber: effect on technological quality properties of pangasius mince emulsion-type sausage.

BACKGROUND: The aim of the work was to investigate the influence of supplementing pangasius mince-based emulsion sausages with blue agave-derived inulin at 1% (T1), 2% (T2), 3% (T3), 4% (T4), and 5% (T5) on its technological quality attributes and acceptability. RESULTS: The cooking yield of T-2, T-3, and T-4 sausages (96-97%) exhibited no significant difference (P > 0.05), which was higher than the other lots. The T-2 batter exhibited a significant difference with all other treatments, showing the lowest total expressible fluid (12.20%) value, indicating the highest emulsion stability of the batter. There was a significant effect on the diameter reduction of the cooked sausages as the level of inulin increased. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed the proteolysis of raw mince without inulin and new bands in cooked sausage samples were observed. Increasing inulin content increased the hardness of the sausages from 2510.81 ± 114.31 g to 3415.54 ± 75.88. The differential scanning calorimetry melting temperatures of peak 2 of the T-1, T-2, T-3, and T-4 increased as the inulin content increased from 1 to 4%. The scanning electron microscope images exhibited a smooth appearance on the surface as the inulin level increased. CONCLUSION: The sausages incorporated with the 2% and 3% blue agave plant-derived inulin (T-2 and T-3) showed better sensory overall acceptability scores than the control. The results suggested that the blue agave plant-derived inulin could be efficiently utilized at the 2% and 3% levels to enhance the quality of emulsion-type pangasius sausage. © 2023 Society of Chemical Industry.

Moving towards Gel for Fish Feeding: Focus on Functional Properties and Its Acceptance.

To resurrect and establish a low-impact aquaculture practice, gel-based feed applications hold promise. Gel feed is viscoelastic, nutrient-dense, hard, flexible, and appealing, and can be moulded into appealing shapes to ensure rapid acceptance by fish. The purpose of this research is to create a suitable gel feed using various gelling agents and to evaluate its properties and acceptance by a model fish, Pethia conchonius (rosy barb). Three gelling agents, viz. starch, calcium lactate and pectin, were included at 2%, 5%, and 8% in a fish-muscle-based diet. The physical properties of gel feed were standardized using texture profile analysis, sinking velocity, water and gel stability, water holding capacity, proximate composition, and colour. The lowest levels of nutrient leaching protein (0.57 ± 0.15%) and lipid (14.3 ± 14.30%) were observed up to 24 h in the underwater column. The highest score for overall physical and acceptance characteristics was noted for the 5% calcium lactate-based gel feed. Furthermore, a 20-day acceptance feeding experiment was conducted using 5% calcium lactate to examine its suitability as fish feed. The results indicate a better acceptability (3.55 ± 0.19%) and water stability (-2.5 ± 2.5%) of the gel feed compared to the control, with an improvement in nutrient losses. Overall, the study provides an insight into the application of gel-based diets for ornamental fish rearing, besides ensuring an efficient nutrient uptake and minimal leaching to establish a clean aquatic environment.

Evolutionary analysis of genus Channa based on karyological and 16S rRNA sequence data.

A wide range of diploid number of chromosomes and the body size of Channa congeners are useful combination of characters for studying the factors controlling the body size. In this study, the karyological information was superimposed on the evolutionary tree generated by 16S rRNA mitochondrial gene sequences. Here, the metaphase chromosome complements stained with Giemsa, AgNO3 and CMA3 were prepared from six snakehead murrel fish species collected from northeast India. The diploid chromosome numbers and the fundamental arms of C. aurantimaculata (2n = 52, NF = 98), C. gachua (2n = 56, NF = 84), C. marulius (2n = 44, NF = 58), C. orientalis (2n = 52, NF = 74), C. punctata (2n = 32, NF = 60) and C. striata (2n = 40, NF = 48) were calculated by the analysis of metaphase chromosome complements. Both methods of nucleolar organizer region (NOR) localization, silver nitrate and chromomycin A3, revealed NOR pairs of 1, 2, 3, 1, 4 and 3 in C. aurantimaculata, C. gachua, C. marulius, C. orientalis, C. punctata and C. striata, respectively. The subject species showed primitive type of asymmetrical chromosomes, except the C. punctata. The variation in 2n for C. orientalis (2n = 52, 78) and C. gachua (2n = 52, 78, 104) of a complete haploid set indicates the possibility of either ploidy change in C. orientalis and C. gachua, if we consider 2n = 52 or the Robertsonian rearrangements in different populations of these two species. The chromosome evolution tree was constructed on 16S rRNA ML-phylogenetic tree using ChromEvol 1.3. The analysis of chromosome evolution explained the loss or gain of chromosome, duplications or semiduplications mechanism. For time scaling the chromosomeevolution, the node age of available 16S rRNA gene of Channa species were estimated, which was also used for estimating the time when chromosomal changes occurred in context of geological time-scale.