Hi, my name is Trine Pedersen, and I will present the result from this study where I determined the effect of canola meal inclusion in weanling pig diets containing different concentrations of energy.

Let me start with the background for this study. So far adding canola to the diets for weanling pigs gives a lower energy content in diets. And canola meal may reduce the growth performance by depressing feed intake or because of lower nutrient digestibility. One solution has therefore been to add more fat to the diets to maintain the same net energy content as soybean meal based diets. Furthermore newer varieties has been developed, which are higher in protein and contain less fiber. Which all in all makes canola an attractive replacement for soybean meal in diets for weanling pigs.

Throughout this presentation I will use the abbreviation CM-HP for high protein canola meal and CM-CV for conventional canola meal.

A brief look at the nutritional variation between high protein canola meal and conventional canola meal. We here have the crude protein content for the two canola sources. The blue column represents the high protein canola meal and the orange column represent the conventional canola meal. And this color scheme will be used in the following slides. We see that crude protein content is 7% higher for high protein than conventional canola meal, being 43% protein for high protein canola meal, which is in accordance with previous studies, against 36% for conventional canola meal, which is in the normal range.

When looking at the lysine content, high protein canola meal is also higher than conventional canola meal with 2.35 against 1.88%. In regard to fiber, we see here that conventional canola meal is a little higher in neutral detergent fiber than high protein canola meal. Looking at the gross energy content for the two canola sources, we see here a higher energy content in high protein canola meal than conventional canola meal.

So moving on to the objective of this experiment, which was to evaluate the effects of adding high protein and conventional canola meal in diets fed to weanling pigs with the effect of dietary net energy, and addition of an exogenous enzyme on growth performance and physiological parameters.

In the experiment we used 492 9 kg weanling pigs, which was included in the experiment 2 weeks after weaning. The experiment was a complete randomized block design with 12 treatments And we had 4 different periods in terms of block. And in total 9 replicate pens with 4 to 6 pigs per pen. And the experiment lasted for a 22 day period.

Moving on to the experimental diets. We have here the first 5 treatments, which was formulated to be equal in net energy by adding choice white grease. We have one control, two diets with 20 and 30% high protein canola meal, and 20 and 30% conventional canola meal.

Four diets were formulated without additional choice white grease, which caused the diets to be reduced in net energy. We had two diets with high protein canola meal with 20 and 30 percent inclusion, and two diets with conventional canola meal with 20 and 30 percent inclusion.

In addition, three diets were formulated to test the effect of adding an exogenous carbohydrase to the control diet, a diet containing 30 percent high protein canola meal, and a diet containing 30% conventional canola meal. And these diets were similar to the diet without additional choice white grease.

The enzyme included in the diets was an exogenous carbohydrase from Elanco, which provided 2,000 international units of mannase per kg complete feed.

The planned net energy values for these diets is here shown in this figure. In the figure we have grouped the different treatments—in constant energy which are the first 5 orange columns, where the first column is the control diet and the addition of 20 and 30 percent high protein canola meal and 20 and 30 percent conventional canola meal. The next four green bars are the diets with reduced energy where the first two green columns are addition of 20 and 30 percent high protein canola meal and the two next are 20 and 30 percent conventional canola meal. The last three grey bars are the diets with enzymes where the first grey column is the control diet plus enzyme and the next two columns with 30 percent high protein canola meal and conventional canola meal, respectively. So the first five diets with constant energy showed in orange, were planned to be 2,475 kcal/kg, The diets reduced in energy are shown as the green columns, which decreased in energy from 2,420 to 2,349 kcal/kg. The enzyme added diets, shown in grey reduced in energy from 2,475 to 2,349 kcal/kg.

Both sources of canola meal were analysed for glucosinolate content, where we found a higher content of glucosinolate in high protein canola meal than conventional canola meal.

In this table we see the calculated glucosinolate content in diets with high protein canola meal (the blue column) and conventional canola meal (the orange column) was added by 20 or 30 percent. So in diets with 30 percent high protein canola meal the glucosinolate content did exceed the recommended level which is less than 2 µmol/g.

We recorded average daily gain, average daily feed intake and gain to feed ratio for the 22 day period for all pigs. At the conclusion of the experiment, one pig per pen was sacrificed. And we collected blood samples; intestinal tract and thyroid gland weight; samples from duodenum, jejunum and colon for histological analysis; digesta from ileum, cecum and colon was taken to measure pH in each segment. Furthermore, VFA concentration was measured in cecum. And a fecal sample was taken to calculate apparent total tract digestibility. 

Data from this study were analysed using contrast analysis in SAS. Where one contrast was made to test the effect of canola source, one to test the effect of inclusion level, another to analyse the effect of energy level, and finally one contrast to analyse the effect of adding enzymes. For each contrast, pen was considered as the experimental unit.

And now I will proceed to the results.

If we start with taking a look at average daily feed intake, we did see an effect of the canola source, where the intake of pigs fed diets with conventional canola meal was higher than pigs fed the high protein canola meal diets. However, the inclusion level did not affect the intake.

Looking at the energy level, we observed that average daily feed intake was greater for pigs fed the diets where net energy was allowed to be reduced, compared with pigs fed diets with constant net energy. Finally, the addition of enzymes didn’t affect the average daily feed intake.

So looking at the average daily gain, we observed a lower gain for pigs fed diets with high protein canola meal. And as for average daily feed intake, we didn’t see an effect of inclusion of canola meal on the average daily gain.

As well as for average daily feed intake, the energy level did also affect the average daily gain which was greater for pigs fed diets with reduced net energy compared with pigs fed diets with constant net energy. So, the higher intake and gain means that pigs were able to compensate for the reduced net energy by consuming more feed. And again, here we didn’t we see an effect of adding enzymes to the diets either.

If we instead look at the gain to feed ratio, which ranges from 0.59 to 0.67, we didn’t see an effect of canola source, inclusion level, energy level, or enzyme addition.

If we take a look at the physiological parameters, we only observed minor or inconsistent effects of adding canola meal on intestinal weight and gut fill, pH in digesta, the concentration of VFAs in cecum, or the serum concentration of urea, total nitrogen, and albumin. And I wont discuss these findings further.

But we did see an effect of canola inclusion on thyroid gland and serum IgG concentration, where the thyroid gland weight increased with increasing canola inclusion, and the IgG concentration decreased. Which is likely caused by the glucosinolate inclusion, but no further effect of these parameters was observed.

Finally a look at the total tract digestibility of energy showed a decreased energy digestibility as the inclusion level of canola increased, which most likely reflects the higher content of fiber in canola meal. However, this wasn't enough to influence the growth performance for pigs receiving diets with canola. And we didn’t observe any effect of canola source, energy level, or enzyme addition.

In conclusion, up to 30 percent high protein canola meal or conventional canola meal may be used in diets fed to weanling pigs from 2 weeks post-weaning without major impacts on growth performance or physiological parameters. 

In addition, we can also conclude that the net energy in diets containing canola meal does not have to be similar to corn-soybean meal diets.

And finally, addition of the enzyme failed to improve the nutritional value of canola meal.

Thanks for your attention.