Complexation of multiple mineral elements by fermentation and its application in laying hens

Abstract

To overcome the problems with current mineral supplements for laying hens including low absorption, mineral antagonism, and high cost, we developed mineral element fermentation complexes (MEFC) by synergistically fermenting bean dregs and soybean meal with strains and proteases and complexing with mineral elements. The fermentation complexation process was optimized based on the small peptide and organic acid contents and the complexation rate of mineral elements after fermentation. The optimal conditions were as follows: the total inoculum size was 5% (v/w), 15% (w/w) wheat flour middling was added to the medium, and mineral elements (with 4% CaCO₃) were added after the completion of aerobic fermentation, fermentation at 34°C and 11 days of fermentation. Under these conditions, the complexation rates of Ca, Fe, Cu, Mn, and Zn were 90.62, 97.24, 73.33, 94.64, and 95.93%, respectively. The small peptide, free amino acid, and organic acid contents were 41.62%, 48.09 and 183.53 mg/g, respectively. After 60 days of fermentation, 82.11% of the Fe in the MEFC was ferrous ions, indicating that fermentation had a good antioxidant effect on ferrous ion, and the antioxidant protection period was at least 60 days. Fourier transform infrared spectroscopy showed that the mineral ions were complexed with amino and carboxyl groups. The added mineral elements promoted microbial growth, protein degradation, and organic acid secretion and significantly improved fermentation efficiency. Animal experiments showed that MEFC had positive effects on several parameters, including production performance (average daily feed intake, P < 0.05; egg production rate, P < 0.05; and average egg weight, P < 0.05), mineral absorption, intestinal morphology (villus height to crypt depth ratio in the jejunum and ileum, P < 0.05), and blood routine and biochemical indexes (red blood cells, P < 0.05; hemoglobin, P < 0.05). This study provides theoretical support for the development of mineral complexes for laying hens via fermentation.

Keywords: bean dregs; laying hen; mineral element absorption; mineral element complex; soybean meal; synergistic fermentation.

FIGURE 1

(A) Effect of timing of adding mineral elements on the complexation rate; (B) Effect of amount of CaCO₃ added on the complexation rate; (C) Effect of amount of CaCO₃ added on contents of small peptides and organic acids; (D) Effect of carbon sources on the complexation rate; (E) Effect of carbon sources on contents of small peptides and organic acids; Values expressed as mean ± standard deviation (n = 3).

FIGURE 2

(A) Effect of fermentation temperature on the complexation rate; (B) Effect of fermentation temperature on contents of small peptides and organic acids; (C) Effect of total inoculum size on the complexation rate; (D) Effect of total inoculum size on contents of small peptides and organic acids; (E) Effect of fermentation time on the complexation rate. Values expressed as mean ± standard deviation (n = 3).

FIGURE 3

Fourier transform infrared spectroscopy analysis. FBDSM: fermented bean dregs and soybean meal; MEFC: mineral element fermentation complexes.

FIGURE 4

SDA-PAGE of fermented bean dregs and soybean meal (FBDSM) and mineral element fermentation complexes (MEFC) proteins. M: protein molecular weight markers (5∼245kDa); 1: FBDSM; 2: MEFC; 3: raw materials.

FIGURE 5

(A) Effect of fermentation on the redox of Fe²⁺ and Fe³⁺; (B) Effect of mineral elements on the number of viable microorganisms; (C) Effect of mineral elements on the growth of Bacillus subtilis and Saccharomyces cerevisiae; (D) Effect of mineral elements on the growth of Lactobacillus. Values expressed as mean ± standard deviation (n = 3).