The Fermentation Process Improves the Nutritional Value of Rapeseed Cake for Turkeys—Effects on Performance, Gut Bacterial Population and Its Fermentative Activity

Aleksandra Alicja Drażbo,Paweł Konieczka,Agata Józefiak,Jerzy Juśkiewicz

doi:10.3390/ani10091711

Abstract

Simple SummaryRapeseed cake (RC) could be valuable raw material in turkey diets, but its wide use is limited by the presence of anti-nutritional factors that are detrimental to gut function. The fermentation process contributes to the degradation of over 80% of carbohydrates, 30% of lignin, and 45% of total glucosinolates in RC, which are harmful to birds. Our research showed that fermentation can improve the nutritional value of RC, enabling good performance and maintainenance of a healthy gut in birds. Therefore, FRC appears to be highly promising in commercial turkey nutrition.This experiment investigated the potential inclusion of fermented rapeseed cake (FRC) in turkey diets. The turkeys received diets either not supplemented (C) or supplemented with raw rapeseed cake (RRC) or FRC at 150 g/kg diet. In comparison with RRC, turkeys receiving FRC achieved significantly higher final BW comparable with that noted in the control group. The dietary inclusion of FRC increased the concentrations of propionic and valeric acid in the cecal digesta compared with the control group, and increased the proportion of butyric acid in SCFA profile compared with RRC group. The activities of glycolytic bacterial enzymes in the cecal digesta, were lowest in turkeys fed FRC. Experimental diets did not cause a shift in the relative abundances of the main bacterial phyla or orders in the cecal digesta. FRC increased the abundance of Bacteroidaceae at the family level, but decreased the abundance of Lactobacillus at the genus level compared with birds fed RRC. In conclusion, the dietary inclusion of FRC at 150 g/kg did not compromise bird performance, did not excessively stimulate bacterial activity, and did not cause shifts in the bacterial composition in the cecum. Actually, FCR exerted several beneficial effects that contributed to maintaining gut health in turkeys, which points to its advantage over RRC.

Highlights

Rapeseed cake (RC), a by-product of oil production, could be a valuable component of poultry diets because it contains up to 400 g/kg crude protein (CP) and high concentrations of metabolizable energy [1,2]
Fermentation increased the content of DM, CP, and crude fiber (CF), and decreased the content of anti-nutritional factors in RC (Table 2)
Fermentation had no effect on non-starch polysaccharides (NSP) concentrations in RC

Summary

Introduction

Rapeseed cake (RC), a by-product of oil production, could be a valuable component of poultry diets because it contains up to 400 g/kg crude protein (CP) and high concentrations of metabolizable energy [1,2]. High NSP levels in poultry diets may stimulate the proliferation and activity of gut microbiota [4], and increase the viscosity of small intestinal digesta, impairing the rate of food passage and nutrient utilization [3]. Glucosinolates hydrolyzed by the enzyme myrosinase are the most toxic compounds in rapeseed, and their maximum level in animal feed should not exceed 2.5 μmol/g [5]. Previous studies indicate that the impact of rapeseed products, rich in NSP, lignin and polyphenols and in glucosinolates, may be more pronounced in turkeys than in broiler chickens due to a much longer fattening period in the former [4]. The inclusion rates of rapeseed products in poultry diets should not exceed 15–20% to prevent metabolic disorders caused by glucosinolates and not to compromise the growth performance of birds [6,7]

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