The influence of casein and urea as nitrogen sources on in vitro equine caecal fermentation

An in vitro model for caecal proteolytic fermentation potential of ingredients in broilers

Fermentation of protein in the caeca of chickens may lead to the production of potentially detrimental metabolites, which can reduce gut health. A poor precaecal digestion is expected to increase protein fermentation (PF), as more proteins are likely to enter the caeca. It is unknown if the undigested protein that enters the caeca differs in fermentability depending on their ingredient source. In order to predict which feed ingredients increase the risk of PF, an in vitro procedure was developed, which simulates the gastric and enteric digestion, subsequent caecal fermentation. After digestion, amino acids and peptides smaller than 3.5 kD in the soluble fraction were removed by means of dialysis. These amino acids and peptides are assumed to be hydrolysed and absorbed in the small intestine of poultry and therefore not used in the fermentation assay. The remaining soluble and fine digesta fractions were inoculated with caecal microbes. In chicken, the soluble and fine fractions enter the caeca, to be fermented, while insoluble and coarse fractions bypass them. The inoculum was made N-free to ensure bacteria would require the N from the digesta fractions for their growth and activity. The gas production (GP) from the inoculum, therefore, reflected the ability of bacteria to use N from substrates and was an indirect measure for PF. The Maximum GP rate of ingredients averaged 21.3 ± 0.9 ml/h (mean ± SEM) and was in some cases more rapid than the positive control (urea, maximum GP rate = 16.5 ml/h). Only small differences in GP kinetics were found between protein ingredients. Branched-chain fatty acids and ammonia concentrations in the fermentation fluid after 24 hours showed no differences between ingredients. Results indicate that solubilised undigested proteins larger than 3.5 kD are rapidly fermented independent of its source when an equal amount of N is present.

Optimization of industrial (3000 L) production of Bacillus subtilis CW-S and its novel application for minituber and industrial-grade potato cultivation

A commercial plant probiotic product was developed employing Bacillus subtilis CW-S in submerged fermentation. The effects of molasses and urea on cell growth were investigated with the goal of low-cost manufacturing. Plackett–Burman and Central-Composite Design (CCD) were utilized to optimize production parameters to maximize productivity. The stability of the formulated product and its efficacy in cultivating minituber in aeroponics and industrial-grade potatoes in the field were assessed. The results showed that the medium BS10 (molasses and urea) produced satisfactory cell density (7.19 × 10⁸ CFU/mL) as compared to the control (1.51 × 10⁷ CFU/mL) and BS1-BS9 (expensive) media (1.84 × 10⁷–1.37 × 10⁹ CFU/mL). According to validated CCD results, optimized parameters fitted well in pilot (300 L; 2.05 × 10⁹ CFU/mL) and industrial (3000 L; 2.01 × 10⁹ CFU/mL) bioreactors, resulting in a two-fold increase in cell concentration over laboratory (9.84 × 10⁸ CFU/mL) bioreactors. In aeroponics, CW-S produced excellent results, with a significant increase in the quantity and weight of minitubers and the survival rate of transplanted plantlets. In a field test, the yield of industrial-grade (> 55 mm) potatoes was increased with a reduction in fertilizer dose. Overall, the findings suggest that CW-S can be produced commercially utilizing the newly developed media and optimized conditions, making plant probiotics more cost-effective and accessible to farmers for crop cultivation, particularly in aeroponic minituber and industrial-grade potato production.

Effects of Sodium Caseinate and Varying Protein Sources on In Vitro Fermentation of Forages by Mixed Equine Cecal Microorganisms

To assess the impact of protein on fermentation by equine cecal microorganisms, cecal fluid from 4 cecally cannulated horses was used to inoculate fermentation bottles containing buffer, forage, and supplemental protein. In experiment 1, sodium caseinate (SC) provided 0, 0.5%, 1%, 2%, or 4% additional crude protein (CP) to bottles containing alfalfa or native warm-season prairie grass hay. Bottles were equipped with continuous gas pressure monitors and placed into a shaking incubator for 48 hours at 39°C. Cultures with alfalfa had greater (P < .0001) in vitro dry matter disappearance (IVDMD), neutral detergent fiber disappearance (NDFD), acid detergent fiber disappearance (ADFD), cumulative gas production, and total volatile fatty acid (VFA). Sodium caseinate increased gas production (P ≤ .05) and decreased pH (P < .003) in cultures with grass hay. Sodium caseinate at 1%, 2%, or 4% additional CP increased IVDMD, NDFD, and ADFD (P < .01), while 4% additional CP also increased total VFA (P < .01). For experiment 2, SC, fishmeal, soybean meal (SBM), whey, porcine blood plasma, and L-lysine hydrochloride were added to supply 2% additional CP to cultures with grass hay. All protein sources decreased pH and increased IVDMD, NDFD, and ADFD (P ≤ .01), with the largest effects elicited by SC, L-lysine, and whey (P ≤ .05). Total VFA (P ≤ .04) and gas (P ≤ .05) production increased with L-lysine, whey, SC, SBM, and fishmeal. While protein supplementation had minimal effects on cultures containing alfalfa, it altered fermentation of grass hay, more notably with more soluble protein sources.