Proximate Composition and Stability of Bacillus Probiotics in Chicken Feed Formulated with Fermented Kapok Seeds

Abstract

Rapid population growth, rising incomes, and increased urbanization have led to a global surge in demand for high-quality protein foods, primarily sourced from animal products like poultry. To meet high consumer demand, poultry farmers often use antibiotics such as tetracyclines, aminoglycosides, penicillins, and fluoroquinolones to prevent infections and promote growth. However, this practice has resulted in the emergence of antibiotic-resistant bacteria, as well as residue detected in poultry eggs, thereby posing serious public health risks. Probiotics have emerged as promising alternatives, enhancing the immune system and gut health of poultry. Kapok seeds, rich in nutrients, and a potential probiotic source are less explored as a source of probiotics and nutrient-dense poultry feed in Ghana. This study aims to evaluate the composition, antimicrobial properties, and stability of chicken feed formulated with Bacillus fermented kapok seeds as a cost-effective probiotic alternative. B. subtilis, B. safensis, B. amyloliquefaciens, and B. methylotrophicus probiotics were cultured and used to ferment a mixture of sterilized kapok and cassava flour. The fermentation process was monitored for pH and temperature changes and Bacillus spore concentration. Post fermentation, the product was split into two parts: oven-dried and freeze-dried. The dried samples were analyzed for moisture content and Bacillus spore concentration. These samples were then used to formulate poultry feed with varying probiotic content (FF1; 90 % (w/w) basal feed and 10 % (w/w) kantong, FF2; 85 % (w/w) basal feed and 15 % (w/w) kantong, and FF3; 80 % (w/w) basal feed and 20 % (w/w) kantong). The feed's proximate composition was analyzed, and its shelf-life was studied at different temperatures (25°C, 35°C, and 45°C) focusing on Bacillus spore viability and mold counts. A six-week feeding trial with day-old chicks evaluated the antimicrobial effects of the probiotic feed on chicken gut pathogens. Post-trial assessments measured Bacillus spore concentration in the gut and the presence of pathogens like E. coli, Shigella, and Salmonella. The agar well diffusion method tested the antimicrobial activity of the Bacillus isolates against broiler gut pathogens. The study found that fermentation characteristics, particularly pH and temperature were stable without a significant changes during the fermentation. Both oven and freeze-drying methods reduced moisture content and microbial load. Furthermore, feed formulations with kapok seed showed significant nutritional variations with higher crude fat content, crude fibre content, and protein content than existing basal feed. The three probiotic feed formulations showed higher Bacillus spore concentrations in broilers' large intestines, leading to reduced E. coli concentrations. Moreover, shelf-life analysis of the probiotic feeds at 25, 35, and 45 degrees showed that Bacillus spores were present in the feeds after three weeks of analysis. However, the concentrations of Bacillus spores in the formulated feeds at 45 degrees were higher as compared to other temperatures even after four weeks of analysis. For the in vitro antimicrobial activity, only B. safensis isolates showed strong inhibition against E. coli isolates.