The potential of Spirulina platensis to substitute antibiotics in Japanese quail diets: impacts on growth, carcass traits, antioxidant status, blood biochemical parameters, and cecal microorganisms.

The development of antibiotic-resistant microorganisms prompted the investigation of possible antibiotic substitutes. As a result, the purpose of the current study is to assess the effect of dietary Spirulina platensis extract as an antibiotic alternative on Japanese quail (Coturnix japonica) growth, antioxidant status, blood parameters, and cecal microorganisms. There was a total of 150 Japanese quails used in this study, divided equally among 5 experimental groups (10 birds per group with 3 replicates): group 1 (G1) received a basal diet without any S. platensis extract, group 2 (G2) received a basal diet supplemented with 1 mL S. platensis extract/kg, group 3 (G3) received a basal diet supplemented with 2 mL S. platensis extract/kg, group 4 (G4) received a basal diet supplemented with 3 mL S. platensis extract/kg, and group 5 (G5) received a basal diet supplemented with 4 mL S. platensis extract/kg from d 7 until d 35. The results showed that compared to the control birds in G1, Japanese quail supplemented with 4 mL of S. platensis extract/kg of diet (G5) had significantly better live body weight, body weight gain, feed intake, feed conversion ratio, digestive enzymes, blood parameters, liver and kidney functions, lipid profile, antioxidant profile, immunological parameters, and cecal microorganism's count. There were no significant changes in the percentage of carcasses, liver, and total giblets among all the 5 groups. Only gizzard percentage showed a significant increase in G2 compared to birds in G1. In addition, intestinal pH showed a significant drop in G2 and G5 compared to birds in G1. After cooking the quail meat, the juiciness and tenderness increased as S. platensis extract levels increased, whereas aroma and taste declined slightly as S. platensis extract levels increased. Furthermore, when a high concentration of S. platensis extract was used, the lightness of the meat reduced while its redness and yellowness increased. The disk diffusion assay showed that S. platensis extract had significant antibacterial activity against Staphylococcus aureus, Listeria monocytogenes, Campylobacter jejuni, and Salmonella typhi, with inhibition zones ranging from 16 to 42 mm. This activity may be attributable to the volatile chemicals in S. platensis extract, of which Geosmin and 2-methylisoborneol are the primary components. In the diet of Japanese quails, it is possible to draw the conclusion that the extract of S. platensis can be utilized as a feed additive and as an alternative to antibiotics.

Evaluation of Green Silver Nanoparticles Fabricated by Spirulina platensis Phycocyanin as Anticancer and Antimicrobial Agents.

Green nanotechnology has attracted attention worldwide, especially in treating cancer and drug-resistant section 6 microbes. This work aims to investigate the anticancer activity of green silver nanoparticles synthesized by Spirulina platensis phycocyanin (SPAgNPs) on two cancer cell lines: Lung cancer cell line (A-549) and breast cancer cell line (MCF-7), compared to the normal human lung cell line (A138). We also aimed to investigate the bactericidal activity against Staphylococcus aureus ATCC29737, Bacillus cereus ATCC11778, Escherichia coli ATCC8379, and Klebsiella pneumonia, as well as the fungicidal activity against Candida albicans (ATCC6019) and Aspergillus niger. The obtained SPAgNPs were spherical and crystalline with a size of 30 nm and a net charge of -26.32 mV. Furthermore, they were surrounded by active groups responsible for stability. The SPAgNPs scavenged 85% of the DPPH radical with a relative increase of approximately 30% over the extract. The proliferation of cancer cells using the MTT assay clarified that both cancer cells (A-549 and MCF-7) are regularly inhibited as they grow on different concentrations of SPAgNPs. The maximum inhibitory effect of SPAgNPs (50 ppm) reached 90.99 and 89.51% against A-549 and MCF7, respectively. Regarding antimicrobial activity, no inhibition zones occurred in bacterial or fungal strains at low concentrations of SPAgNPs and the aqueous Spirulina platensis extract. However, at high concentrations, inhibition zones, especially SPAgNPs, were more potent for all tested microorganisms than their positive controls, with particular reference to Staphylococcus aureus, since the inhibition zones were 3.2, 3.8, and 4.3 mm, and Bacillus cereus was 2.37 mm when compared to tetracycline (2.33 mm). SPAgNPs have more potent antifungal activity, especially against Aspergillus niger, compared to their positive controls. We concluded that SPAgNPs are powerful agents against oxidative stress and microbial infection.