Effects of thermal processing on digestibility and protein utilization of rapeseed meal of medium and low glucosinolate type in diets for growing pigs

Matti Näsi,Hilkka Siljander-Rasi

doi:10.23986/afsci.72412

Abstract

The nutritive value of rapeseed meals (RSM) from Brassica campestris, 0 and 00-cultivars, with medium (25—55 μg/g defatted meal) and low (0.05), although 00-RSM’s tended to have higher OM and CP digestibilities compared with 0-RSM; pooled mean values being 0.638 vs. 0.715 for OM and 0.715 vs. 0.775 for CP. RSM treated for ruminant escape protein had the same or better digestibility than untreated RSM; pooled average values being 0.669 vs. 0.680 for OM and 0.746 vs. 0.757 for CP. This observation has practical importance since the same treatments of RSM could be employed for meals to be used in diets of both ruminants and pigs. In these experiments, the protein utilization was efficient and differences between the dietary treatments were small and insignificant. Heat treatment (Opex) did not decrease protein utilization despite a small reduction in lysine content.

Highlights

Production of rapeseed is one of the most readily available means of increasing the domestic supply of protein of high biological value in Finland
The individual components of GL in relation to others did not vary between varieties
Extrusion has been shown to inactivate myrosinase efficiently but has had relatively little effect on glucosinolate content, unless chemicals were added before extrusion (Fenwick et al 1986)

Summary

Introduction

Production of rapeseed is one of the most readily available means of increasing the domestic supply of protein of high biological value in Finland. The harvested seed is rich in oil and protein, the former being increasingly used for human consumption. Production of rapeseed oil for fuel purposes is under evaluation, which means increased oil seed meal supply as a protein source for animal feeding. Removal of the oil leaves rape seed meal (RSM) containing 350—400 g/kg crude protein with an amino acid balance that compares well with that of soybean meal. Whilst RSM is currently included in ruminant rations with promising response Many investigations have shown RSM as a potential replacement for e.g. soybean meal (Kiiskinen 1984, NAsi et al 1985)

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