Hello, everyone. My name is She Yue. I'm a visiting Ph. D. student of Dr. Stein's lab. Today I will talk about effects of high protein canola meal on digestibility of phosphorus and growth performance in pigs.

First I will start with a short background about composition of high protein canola meal, the STTD of phosphorus, and growth performance of pigs fed canola meal. Then, I will mention the materials and methods that were used in this experiment. Then we’ll take a look into the results, and at the end I will give you some conclusions.

Traditionally, the use of nutrients in canola meal by pigs is limited by its high dietary fiber content, less crude protein, and reduced amino acid digestibility compared with soybean meal. However, recently new varieties of canola with larger seeds are developed. The crude protein in the meal is increased whereas NDF concentration is reduced.

The total calcium concentration in high protein canola meal and conventional canola meal is twice as in soybean meal. The total phosphorus concentration in high protein canola meal is twice as in soybean meal. But most of the phosphorus in canola meal is phytate bound phosphorus.

Recent research has demonstrated that values for the standardized total tract digestibility of phosphorus can reflect the phosphorus utilization by pigs more accurately than values for the apparent total tract digestibility. And it's additive in the mixed diets. The STTD of phosphorus in conventional canola meal fed to pigs has been reported. However, comparison of the STTD of phosphorus among high protein canola meal, conventional canola meal, and soybean meal has not been determined.

Around 80% of phosphorus in canola meal is phytate bound phosphorus, which can be poorly digested by pigs. Now microbial phytase is widely used to improve the phosphorus digestibility in canola meal and soybean meal.

Our previous study collected 18 canola meal samples and demonstrated that adding 500 units of microbial phytase can improve the STTD of phosphorus in conventional canola meal from around 49% to 68%.

It has been demonstrated that glucosinolates may affect palatability of diets.

The reason we chose weanling pigs is because they are sensitive to glucosinolates.

Previous study suggested the negative influence of dietary glucosinolates on growth performance may be related to the drastic endocrine disturbance. Negative effects of glucosinolates on pigs are relative to its concentration in diet.

The reason that canola meal may affect growth performance is that canola meal is high in fiber.

Canola meal has less ME and reduced SID of amino acids.

If diets are formulated based on determined values for SID amino acid, ME, and STTD phosphorus, it is expected that high protein canola meal and conventional canola meal can be used without reducing growth performance.

Therefore, the objective of this study was to determine the ATTD and STTD of phosphorus in growing pigs of canola meal produced from high-protein canola and to compare these values to values obtained for conventional canola meal.

The second objective of this study was to determine the optimum inclusion rate of high protein and conventional canola meal in diets fed to weanling pigs.

Experiment 1 is to compare the STTD of phosphorus in high protein canola meal, conventional canola meal, and soybean meal.

In this experiment, 48 pigs with initial body weights of 17 kg were allotted to a randomized complete block design using a 2 × 3 factorial arrangement with 8 replicate pigs per diet.

A total of 6 diets were formulated by using each ingredient as the only source of phosphorus in a diet that was based on sucrose and cornstarch, without or with 500 units of microbial phytase.

Total fecal collection was conducted using a marker-to-marker approach. The STTD of phosphorus in each ingredient, and the ATTD of calcium in each diet, were determined.

The ingredients used in this experiment were the same batches of our previous study.

In our previous research, we determined the DE, ME, and SID of amino acid in high protein canola meal, conventional canola meal, and soybean meal.

And our current study examined the STTD of phosphorus and performance.

In this study, the concentration of glucosinolates in high protein canola meal is less than in conventional canola meal.

A source of canola meal produced from a novel variety of high protein canola meal, conventional canola meal, and soybean meal were used. Three diets were formulated by using each ingredient as the only source of phosphorus in the diets. Diets were based on cornstarch, sucrose, and the test ingredient.

Three additional diets were formulated as the initial three diets, with the exception that 500 units of microbial phytase was added to each diet.

The calcium concentration among diets are similar.

The phosphorus concentration in soybean meal diets is less than in high protein canola meal or conventional canola meal diets.

Let’s move to results of Experiment 1. 

Pigs fed the high protein canola meal diet had the greatest daily absorption of phosphorus, and microbial phytase increased the absorption of phosphorus when added to all ingredients except for pigs fed the soybean meal diet.

The ATTD of phosphorus in soybean meal was greater than for conventional canola meal and high protein canola meal, but no differences between conventional canola meal and high protein canola meal diets were observed. However, the ATTD of phosphorus was greater in diets with phytase than in diets without phytase.

The STTD of phosphorus was greater in soybean meal diets than in conventional canola meal and high protein canola meal diets. Although the digestibility of phosphorus in soybean meal is greater than in both sources of canola meal, the digestible phosphorus in canola meal is still greater than in soybean meal, because the total phosphorus content in canola meal is relatively high. Microbial phytase also increased the STTD of phosphorus in all diets. These results indicated in addition to providing protein, canola meals can also be an optional source for phosphorus among plant feed ingredients in swine diets, especially with certain amount of microbial phytase supplement.

So far, we are not aware of other experiments with pigs in which calcium digestibility is compared among high protein canola meal, conventional canola meal, and soybean meal. But our results showed the ATTD of calcium in diets that contained soybean meal is greater than in high protein canola meal or conventional canola meal.

From Experiment 1, we concluded that there is no difference in the ATTD or STTD of phosphorus in high protein canola meal and conventional canola meal.

The ATTD and the STTD of phosphorus in soybean meal is greater than high protein canola meal and conventional canola meal.

Microbial phytase increases the digestibility of phosphorus regardless of the ingredient.

Experiment 2 is to determine the effects of high protein canola meal and conventional canola meal on growth performance.

A total of 405 weanling pigs were randomly allotted to 9 dietary treatments with 9 replicate pens per treatment.

Nine diets were prepared with the control diet being based on corn and soybean meal.

Four diets were formulated by adding 10, 20, 30, or 40% high protein canola meal to the control diet primarily at the expense of soybean meal.

And the last 4 diets were formulated by adding 10, 20, 30, or 40% of conventional canola meal to the control diet. Pigs were fed the experimental diets for 3 weeks.

Pig body weights were recorded at the start and the conclusion of the experiment and daily feed allotments were recorded as well to calculate the average daily gain, the average daily feed intake, and the average gain:feed ratio.

This table shows the diets of this experiment. Canola meal replaced soybean meal on an equal digestible lysine basis in these diets. All diets were formulated to meet current estimates for nutrient requirements for weanling pigs.

Now let’s move to the results of Experiment 2.

The average daily feed intake was linearly reduced when pigs were fed diets with increasing inclusion levels of high protein canola meal or conventional canola meal.

Increased inclusion level of conventional canola meal quadratically increased the average daily gain of pigs, but no effect was observed in average daily gain from including high protein canola meal in the diets. Including up to 40% high protein canola meal or conventional canola meal, the average daily gain is greater than pigs fed the control diet.

The gain:feed ratio was linearly increased when pigs fed diets with increasing inclusion levels of high protein canola meal or conventional canola meal.

From Experiment 2, we concluded that including up to 40% high protein canola meal or conventional canola meal has no negative effects on growth performance of weanling pigs.

Pigs fed conventional canola meal diets had greater average daily gain and gain:feed ratio compared with pigs fed high protein canola meal diets.

Overall, the two experiments concluded the STTD of phosphorus in high protein canola meal is similar to conventional canola meal and response to microbial phytase is also similar to conventional canola meal.

If diets are formulated based on STTD of phosphorus, SID of amino acid, and ME, up to 40% conventional canola meal or high protein canola meal may be used in diets for weanling pigs without reducing growth performance.

If diets can be formulated less expensive by using high protein canola meal or conventional canola meal, there is no reason not to use these ingredients.

That's all. Thank you.