Nano-delivery of trace minerals for marine fish larvae: influence on skeletal ossification, and the expression of genes involved in intestinal transport of minerals, osteoblast differentiation, and oxidative stress response

Effect of Dietary Inorganic and Chelated Trace Mineral Supplementation on the Growth Performance and Skeletal Deformities of European Seabass and Senegalese Sole Post-larvae

Trace elements such as Cu, Fe, Mn and Zn are essential minerals in fish diets, especially important at early larval stages. The chemical speciation of these elements directly influences their uptake efficiency and metabolic utilization. In order to optimize the form of trace elements incorporated into larval feed, two experiments were conducted using two commercial fish species, European seabass (Dicentrarchus labrax) and Senegalese sole (Solea senegalensis), and two chemical forms (inorganic and glycinate chelates). Several fish performance parameters were measured, as well as bone status parameters to assess which form of mineral results in optimal fish biological performance. European seabass and Senegalese sole post-larvae were unresponsive (P > 0.05) to dietary treatments in terms of dry weight (DW), standard length (SL), relative growth rate (RGR) or feed conversion rates (FCR) when fed diets supplemented with chelated over inorganic trace minerals. This study suggests that replacing dietary inorganic mineral supplementation by their organic glycinate-chelated forms brings no beneficial effects on somatic growth and bone development in Senegalese sole and European seabass post-larvae fed high-quality commercial microdiets. Additionally, we show that mineral leaching from diets can be significant, but the use of chelated minerals can potentially mitigate this leaching phenomenon. Therefore, the selection of the dietary mineral form should take into account not only their economic value, but also their biological effect and environmental impact. Data generated in this trial provides new knowledge in trace mineral nutrition of early-stage marine fish.

Use of Chemical Nano-Selenium as an Antibacterial and Antifungal Agent in Quail Diets and Its Effect on Growth, Carcasses, Antioxidant, Immunity and Caecal Microbes

Nano-minerals are used to enhance mineral bioavailability, which helps improve animal growth and health. The use of chemical nano-selenium (Che-SeNPs) has lately attracted great scientific interest, mainly due to its potential benefits for poultry. The current study was conducted to investigate the impact of the dietary supplementation of Che-SeNPs on the growth performance, carcass traits, blood constituents, antioxidant status, immunity, and gut microbiota of Japanese quails. A total of one week-old 180 Japanese quails were randomly distributed into four equal groups, and each group consisted of 45 unsexed birds with five replications (nine birds each). The first group was fed a basal diet without supplementation (0 g/kg Che-SeNPs), and the second, third, and fourth groups were fed diets containing 0.2, 0.4, and 0.6 g/kg Che-SeNPs, respectively. The results showed that the dietary supplementation of Che-SeNPs significantly (p < 0.0001) increased body weight, body weight gain, and feed conversion ratio, but decreased feed intake (p < 0.0001) compared to the control group. The highest values of growth performance were recorded in the group fed 0.4 g Che-SeNPs g/kg feed. Che-SeNPs levels did not affect the carcass traits, relative organs (except liver), or blood hematology (except platelet count and hemoglobin level) of quails. Plasma total protein, albumin, aspartate amino transferase (AST), and urea values were not affected by dietary Che-SeNPs, but alanine aminotransferase and lactate dehydrogenase values declined. Globulin and creatinine values were linearly increased with the inclusion of Che-SeNPs (0.4 and 0.6 g/kg) in quail diets compared to the control. The supplementation of Che-SeNPs in quail diets significantly improved (p < 0.05) the plasma lipid profile and activities of antioxidant enzymes compared to the control group. Immunoglobulin G values of Che-SeNPs (0.4 and 0.6 g/kg) were higher (p < 0.05) than those in the control group. The groups fed diets supplemented with Che-SeNPs showed lower (p < 0.0001) total bacterial count, total yeast and molds count, Coliform, Escherichia coli, Enterococcus spp., and Salmonella spp. colonization, and higher (p = 0.0003 and 0.0048) lactic acid bacteria counts than those in the control group. In conclusion, Che-SeNPs supplemented up to 0.4 g/kg can improve the performance, lipid profile, antioxidant indices, and immunity, as well as decrease intestinal pathogens in quails during the fattening period (1-5 weeks of age).

Trial for use nanoselenium particle with different dietary regime in Oreochromis niloticus and Mugil cephalus polyculture ponds: Growth efficiency, haematological, antioxidant, immunity and transcriptional analysis

Background

Fish farming is one of the most productive economies in the world. One of the essential goals in fish production is to minimize processing costs while maintaining and increasing the vital functions, weight and immunity of fish.

Objective

We conducted this study to explore nanoselenium (Nano‐Se) particles in various feeding schemes.

Material and Method

Nano‐Se particles incorporated in the basal diet at (0.5 mg/kg diet), and the fish was divided into six groups after adaptation as the follows: The first group was feed daily with a diet containing Nano‐Se (0.5 mg/kg diet); the second group was exposed to a feeding programme in which it has day feeding followed by day of starvation with a diet containing Nano‐Se (0.5 mg/kg diet); the third group was day feeding followed by 2 days of starvation; the fourth group served as a negative control group in which this group was continuous feeding with a basal diet without Nano‐Se; the fifth group was day feeding with the basal diet followed by a day of starvation; and the sixth group was day feeding with basal diet followed by 2 days of starvation.

Result

Our result revealed that Group 2 showed significant improvement in haematological parameters, red blood cells and haemoglobin with a substantial increase in total protein (p < 0.05) as well as lysosomal and phagocytic activity with considerable upregulation of growth hormone and insulin growth factor 1 in addition to markedly increase in the pro‐inflammatory cytokines. Finally, this study offers the first‐time dietary regime with Nano‐Se supplementation that saves the feeding cost and increases fish welfare and growth.

Effect of Dietary Manganese and Zinc Levels on Growth and Bone Status of Senegalese Sole (Solea senegalensis) Post-Larvae

Essential dietary trace elements, such as zinc (Zn) and manganese (Mn), critically influence a wide range of physiological, metabolic, and hormonal processes in fish larvae and post-larvae. Despite their importance for normal fish growth and skeletal development, trace mineral nutrition has not been extensively studied in the early stages of development of fish. Post-larvae of an emergent aquaculture species, Senegalese sole (Solea senegalensis), were the subject of this study in order to better understand the effects of diet supplementation of trace minerals upon fish larval development and performance. Sole post-larvae were fed a combination of organic Mn (45 and 90 mg kg^-1 feed) and organic Zn (100 and 130 mg kg^-1 feed) and survival, growth, mineral deposition rates, and vertebral bone status were assessed. Our results showed that although no significant effect was found on the growth performance of Senegalese sole post-larvae, Mn and Zn supplementation to a commercial microdiet for marine fish larvae at higher dietary levels (Mn at 90 mg kg^-1 and Zn at 130 mg kg^-1) improved larval survival, decreased the severity of vertebral malformations, and increased the deposition of Mn in bone.

Effect of Trace Minerals and B Vitamins on the Proliferation/Cytotoxicity and Mineralization of a Gilthead Seabream Bone-Derived Cell Line

Trace minerals and vitamins are known modulators of bone metabolism, and dietary optimization of these components may improve skeletal development and reduce the occurrence of skeleton deformities in farmed fish. As for larval stages, mineral and water-soluble vitamin nutrition requirements are lacking in research efforts and knowledge is scarce. An in vitro cell system developed from gilthead seabream vertebra and capable of mineralization was used to assess the effect of B vitamins (thiamin and pyridoxine) and trace minerals (copper, manganese, and zinc in a sulfated and chelated form) on cell proliferation and extracellular matrix (ECM) mineralization. Dependent on dose, inhibition of cellular proliferation and/or cytotoxic effects was observed for all nutrients tested and LD₅₀ values were determined: copper, 67.4-69.5 ppm; manganese, 20.9-29.8 ppm; zinc, 37.1-42.8 ppm in sulfated and chelated form respectively; thiamin, 6273 ppm; pyridoxine, 14226 ppm. ECM mineralization was enhanced by mineral (dose and form dependent) and vitamin (dose dependent) supplementation, at non-toxic concentrations below the determined LD_50s. This in vitro work confirmed the mineralogenic action of trace minerals and water-soluble vitamins and provided valuable insights for subsequent in vivo nutritional trials.

In ovo injection of nano-selenium spheres mitigates the hatchability, histopathology image and immune response of hatched chicks

In ovo injection of nano-selenium (Se) produced by lactic acid bacteria (LAB-nano-Se) was investigated on the hatchability, immune responses and the histopathological alterations in hatched chicks. The eggs (18 day age) were injected with 0.5 ml of 0.9% NaCl (normal saline, NS), while the control group was kept without injection. In the third, fourth and fifth groups, the eggs were injected with 0.5 ml of NS and LAB-nano-Se at 10, 20 and 30 μg/egg. The results revealed improved growth performance in groups injected with LAB-nano-Se when compared to the control treatment. The highest final weight and weight gain were noticed in 20 μg LAB-nano-Se/egg group (p < .05). The feed conversion ratio was reduced in all treated groups when compared to the control group (p < .05). Groups injected with LAB-nano-Se showed enhanced hatchability of the whole incubated eggs (p < .05). Total lipids and cholesterol levels were decreased significantly in groups treated with LAB-nano-Se at 10 and 20 μg/egg when compared to the non-treated group. At the same time, globulin was increased by LAB-nano-Se in ovo injection. Furthermore, the total antioxidant capacity, catalase, glutathione peroxidase, superoxide dismutase increased in groups treated with LAB-nano-Se at 10 and 20 μg/egg with insignificant (p > .05) differences with those treated with LAB-nano-Se at 30 μg/egg using in ovo injection technique. Also, higher total blood protein and phagocytosis were significantly observed in groups treated with at 10, 20 and 30 μg LAB-nano-Se/egg. The histopathological images of hatched chicks revealed that nano-Se presented normal effects on liver and kidney tissues and restored the parameters as mentioned earlier. To conclude, LAB-nano-Se exhibited beneficial effects in hatched chicks through improving immune and antioxidant activities as well as histopathological effects by using in ovo technique.

Key nutritional factors and interactions during larval development of pikeperch (Sander lucioperca)

The effects of 8 nutritional variables (Ca/P, Eicosapentaenoic acid (20:5n-3) + Docosahexaenoic acid (22:6n − 3) (EPA + DHA), Arachidonic acid (20:4n − 6) (ARA), Se, vitamins E, C, D and A) were investigated to identify their respective importance and interactions in pikeperch larval development. In this respect, two modalities (low and high levels) of each variable were tested through a fractional factorial experimental design allowing a reduction from 256 (2⁸) to 16 (2^8 – 4) experimental units. Survival was significantly higher in larvae fed a high Ca/P diet while larval growth was significantly lower in larvae fed the same diet variant, associated with a higher incidence of kyphosis and pectoral anomalies in these larvae. Lordosis and scoliosis seemed to be mostly affected by dietary long chain polyunsaturated fatty acids (LC-PUFAs). A significant interaction was shown between n-3 LC-PUFA and vitamin C on jaw anomalies, while myocyte-specific enhancer factor 2C (mef2c) gene expression correlated positively with dietary vitamin C increment. Results also demonstrated an effect of the different nutrients and their interactions on the activity levels of digestive enzymatic activities. The results of the present study highlight the importance of the interactions between Ca/P, LC-PUFAs and vitamins C and E, suggesting their essential roles as key nutritional factors influencing pikeperch larval development.