Effects of Fermentation on Standardized Ileal Digestibility of Amino Acids and Apparent Metabolizable Energy in Rapeseed Meal Fed to Broiler Chickens.

Zhengke Wu,Jiang Chen,Jiao Liu,Huiyi Cai,Shoaib Ahmed Pirzado,Yang Li,Guohua Liu

doi:10.3390/ani10101774

Abstract

Rapeseed meal (RSM) is a common protein ingredient in animal diets, while the proportion of RSM in diets is limited because of its anti-nutritional factors. Fermentation based on mixed microbial strains appears to be a suitable approach to improve the nutritive value of rapeseed meal in animal feed. In this study, we evaluated the effects of fermentation on the apparent metabolizable energy (AME) values and standardized ileal digestibility (SID) of amino acids in RSM fed broilers. The AME and nitrogen-corrected apparent metabolizable energy (AMEn) values of RSM and fermented rapeseed meal (FRSM) were determined by the substitution method, with RSM and FRSM proportionally replacing the energy-yielding components of the basal diet by 30%. Results show that fermentation improved AME and AMEn of RSM from 7.44 to 8.51 MJ/kg and from 7.17 to 8.26 MJ/kg, respectively. In the second experiment, two experimental diets were formulated, with RSM and FRSM being the sole sources of amino acids. A nitrogen-free diet (NFD) was also formulated to determine endogenous amino acids losses (EAAL). Feeding on FRSM resulted in higher (p < 0.05) apparent ileal digestibility (AID) and SID of alanine, valine, isoleucine, leucine, tyrosine, lysine, arginine, and phenylalanine. No significant differences between RSM and FRSM were found for AID and SID of asparagine, histidine, threonine, serine, glutamine, praline, glycine, methionine, and cystine. FRSM had greater AMEn values and SID of amino acids compared to RSM, therefore, FRSM was nutritionally superior to RSM in broiler diets.

Highlights

Rapeseed meal (RSM) is a by-product of rapeseed oil production, containing 35–40% crude protein (CP) with abundant sulfur-containing amino acids, and a potential substitute for soybean meal in broiler diets [1,2,3]
The amino acid composition of RSM and fermented rapeseed meal (FRSM) shows that fermentation increased the content of several amino acids in rapeseed meal, especially Asp, Thr, Ser, Glu, Pro, Ala, and Lys (Table 3)
The fermentation of RSM increased the content of polypeptides and increased the content of L-lactic acid compared to unfermented RSM

Summary

Introduction

Rapeseed meal (RSM) is a by-product of rapeseed oil production, containing 35–40% crude protein (CP) with abundant sulfur-containing amino acids, and a potential substitute for soybean meal in broiler diets [1,2,3]. In order to use RSM efficiently, various processing techniques are employed to lower the levels of anti-nutritional factors in RSM, including physical, chemical, enzyme hydrolysis, and biological pretreatments [4,7]. Most of these methods have drawbacks, such as loss of proteins, high cost, reagent residues, and commercial infeasibility. Hydrothermal treatment can break weak bonds between polysaccharides, which contribute a lot to the degradation of glucosinolates, because glucosinolates are a sugar derivative, but high temperatures may increase protein and free amino acid damage. High temperatures may decrease protein digestibility and lower the nutritive values of RSM [8,9]

Methods

Results

Discussion

Conclusion