Proximate composition analysis of commonly used raw materials in Bangladesh and the critical variables impacting soybean meal protein concentration

Abstract

A total of 188 samples of Rice Polish (RP), De-Oiled Rice Bran (DORB), Soybean Meal (SBM), Rapeseed Meal (RSM), Fish Meal (FM), and Poultry by-Product Meal (PBM) were investigated for the proximate composition, focusing on Moisture, Crude Protein (CP), Ether Extract (EE), Ash, and Carbohydrate from diverse sources. Regarding the animal-based ingredients maximal crude protein was observed in Saudi Arabian PBM (67.53±1.01%), while FM had the minimal (59.82±3%). In contrast, among plant-based ingredients, South American region SBM dominated (46.42±0.23%), where RP had the lowest protein value (12.48±0.61%). In the instance of EE, ash, and carbohydrate content in both plant-based and animal-based ingredients Malaysian type 2 PBM (22.12±9.07) showed the highest EE value, where RP (55.68±2.86) and DORB (55.78±2.23) have the highest carbohydrates and FM has the highest ash content (17.81±5.93). Focusing on SBM, the relation of protein with moisture and non-protein nitrogen was observed (NPN), and the result shows a higher degree of variability in NPN (R2=75.94%) rather than moisture (R2=12.24%). NPN with protein solubility (PS) was also observed where PS varies from 77.28% to 56.94% based on the presence of NPN and it defines a 34.04% relationship. The cost analysis revealed that FM was the priciest protein source (0.31 Tk/g) in the present context, followed by PBM (0.19 Tk/g). SBM was a more economical and accessible replacement (0.17 Tk/g) while RSM was the most cost-effective (0.11 Tk/g). This study provides insight into the nutritional composition and economic reflections of different feed ingredients for feed industry applications in Bangladesh.