Pascal Leterme

Summary

The project aimed to generate reliable information on the digestible and net energy (DE and NE) content of different canola meals (CM) in growing pigs, differing in treatment (toasted or not) and in origin (yellow-seeded Brassica junceae and yellow- or black-seeded Brassica napus). The yellow-seeded B. napus CM presented the highest dry matter and energy digestibility and DE and NE content. No difference was observed for toasting. It is concluded that yellow CM could have higher interest for swine than black varieties.

Introduction

Canola meal (CM) is a valuable source of essential amino acids for pigs, although the digestibility of these nutrients is limited by both composition (high dietary fibre level) and processing (toasting). Its low energy value is probably the most limiting factor for its use in swine nutrition and is explained by the absence of digestible carbohydrates and oil and by the relatively high level of dietary fibre.

A breeding programme has been initiated in Canada to develop canola seeds with lower fibre content. It is based on cultivars of B. napus and B. junceae carrying the yellow-seed colour genes.

On the other hand, with the progress obtained in terms of levels of anti-nutritional factors in the seed, research scientists are wondering if the toasting process is still required. Non-toasted meals are yellow but toasting can have a negative impact on the availability of the amino acids.

The present project aimed at evaluating the digestible and net energy content (DE and NE) of non-toasted and toasted canola meals obtained from yellow- and black-seeded B. napus and yellow-seeded B. junceae.

Materials and Methods

Canola meal samples were prepared at POS pilot plant (University of Saskatchewan) to grind, extract oil and apply heat treatment to simulate commercial canola meal production. A total of 42 barrows (28kg on average) were used. The pigs were randomly allocated to one of seven experimental diets (limit feed), these consisted of a basal diet, composed of wheat, soybean meal and a mineral/vitamin premix, and six CM-based diets composed of one-third CM and two-thirds basal diet. After an adaptation period to the diet of 10 days, the faeces were quantitatively collected for 10 days. The samples were then pooled per animal, freeze-dried and analysed at the University of Saskatchewan. The digestibility and DE/NE content of the diets were calculated. The digestibility and DE/NE content of the CM alone were then also calculated (Table 1).

Results

The composition of the six CM samples is detailed in Table 1. The crude protein content ranged from 46 to 52 per cent of the DM, and the NDF content from 16 to 23 per cent. All the CM were very low in fat.

The results of digestibility and energy content are detailed in Table 1. No effect of toasting was observed (P>0.05). On the contrary, differences were observed between the canola types. The DE and NE content of the black-seeded CM of B. napus was lower (P<0.01) than that of the yellow-seeded CM of B. napus and B. junceae.

Conclusion

Yellow-seeded canolas, thanks to their lower fibre content, have a better DE and NE content in pigs than black-seeded canolas. Thanks to low anti-nutritional factors found in the new canola cultivars, the toasting step does not seem to be required anymore to improve the nutritional value.

Canola field in bloom

Acknowledgements

Strategic programme funding was provided by Sask Pork, Alberta Pork, Manitoba Pork Council and Saskatchewan Agriculture and Food Development Fund. Specific funding for this project was provided by the Canola Council of Canada.