The influence of bacterial selenium nanoparticles biosynthesized by Bacillus subtilus DA20 on blood constituents, growth performance, carcass traits, and gut microbiota of broiler chickens

Abstract

Selenium is one of the necessary micronutrients needed for enhanced gut microbiota and oxidative stress of poultry, so it improves their performance. In this study, Bacillus subtilus DA20 isolate that identified at the gene level by PCR was employed to produce eco-friendly selenium nanoparticles (BSeNPs) and investigate their effects on growth performance, carcass characteristics, blood parameters, and gut microbiota of Indian River (IR) broiler chickens. The obtained selenium nanoparticles were spherical with size of 56 nm and net negative charge of -22.36 mV; the BSeNPs were surrounded with active compounds, which besides the tiny size attributed to antioxidant and antibacterial activity. Forty hundred and eighty unsexed IR broilers, 1-day old, were reared for 35 d. The chicks were weighed separately and distributed into 3 treatment groups; each group contained 4 replicates (40 birds per replicate). Chicks in the first, second, third, fourth groups were fed control diets supplemented with 0, 20, 40, and 60 µg/kg of BSeNPs, respectively; but the fifth group was fed 300 µg/kg bulk selenium. Dietary supplementation with BSeNPs (40 µg/kg diet) significantly increased the body weight of chicks and decreased the feed conversion ratio. Additionally, dietary BSeNPs significantly (P = 0.046) lowered the fat content in broiler by 24% compared to the control; on the other hand, the breast muscle significantly increased (P = 0.035) by 19%. The content of total bacterial count (TBC), total yeast mold count (TYMC), E. coli, and Salmonella counts significantly was decreased with BSeNPs and Se compared to the control. However, lactic acid bacteria (LAB) was significantly increased with BSeNPs (60 μg/kg) when compared to control, showing the beneficial effects of BSeNPs in reducing pathogens and enhancing the beneficial bacteria, which reflects on the broiler performance.

Keywords: Bacillus subtilus; blood chemistry; gut microbiota; performance; selenium nanoparticles.

Figure 1

16S rRNA genes of selenium-resistant bacterial isolate, Lane 1, Ladder [(L) 100–1,500 bp]; Lane 2 to 4, Positive controls (P, Bacillus subtitles); Lane 5, identified isolate at 310 bp; Lane 6, Negative control (N, Staphylococcus aureus).

Figure 2

Characterization of BSeNPs fabricated by Bacillus subtitles DA20 supernatant (A) UV absorbance at 270 nm, (B) TEM showed spherical nanoparticles, (C) Size of 56 nm by zeta sizer, (D) Zeta potential records nanoparticles charge of −22.35, (E) Active groups surrounded BSeNPs, (F) Active groups in Bacillus subtitles DA20 detected by FTIR.

Figure 2

Characterization of BSeNPs fabricated by Bacillus subtitles DA20 supernatant (A) UV absorbance at 270 nm, (B) TEM showed spherical nanoparticles, (C) Size of 56 nm by zeta sizer, (D) Zeta potential records nanoparticles charge of −22.35, (E) Active groups surrounded BSeNPs, (F) Active groups in Bacillus subtitles DA20 detected by FTIR.

Figure 3

Antioxidant activity of bacterial selenium nanoparticles (BSeNPs) fabricated by Bacillus subtitles DA20 supernatant. Lowercase letters above columns indicate significant difference at P ≤ 0.05.

Figure 4

Antibacterial activity of bacterial selenium nanoparticles (BSeNPs) fabricated by Bacillus subtitles DA20 supernatant against pathogenic bacteria. Lowercase letters above columns indicate significant difference at P ≤ 0.05.

Figure 5

The effect of dietary BSeNPs on the gut microbiota of IR broiler. Lowercase and uppercase letters above columns indicate significant difference at P ≤ 0.05.