PROJECT RESULTS

Sustainable Pork Production in Manitoba: The Role of Feed Peas

Applicant: 

Dr. Martin Nyachoti

Department of Animal Science

University of Manitoba

Winnipeg, Manitoba  R3T 2N2  Canada

Table of Contents:

• Background and Objectives
• Procedure and Project Activities
• Results and Discussion
• Conclusions

Researchers:

Dr. Martin Nyachoti and Dr. W. Guenter, Department of Animal Science, University of Manitoba

ARDI Project:

#00-362

Total Approved:

$30,000

Date Approved:

June 27, 2000

Project Status:

Completed August, 2003

Background and Objectives:

Peas (Pisum sativum) have considerable potential as a feedstuff for pigs.  Over the past decade, there has been a marked increase in pea production in Western Canada.  At the same time, interest in peas as a feedstuff for swine, in place of imported and often-expensive soybean meal has grown considerably and is expected to continue as the swine industry develops.  However, peas still remain underutilized in commercial feed production compared to soybean meal. 

Peas can serve as a source of protein and energy for pigs.  A common concern in using peas for swine diets is that they tend to vary considerably in nutrient composition.  As a protein source for pigs, protein and amino acid availability in peas needs to be determined to allow for accurate feed formulation.  With respect to amino acid supply in pig diets, it is now recommended to use true digestible coefficients in diet formulation.  However, true ileal amino acid digestibilities in pea cultivars grown in Canada (and Manitoba in particular) have not been determined.  Also, the level of peas that can be safely included in diets for young pigs has not been well established.  The pea cultivars grown in Western Canada have very low levels of anti-nutritional factors and therefore it is possible that young pigs can tolerate higher amounts of dietary pea than currently recommended.

Therefore the objectives of the project were:

1. To characterize the chemical and nutrient profile of a wide variety of Manitoba-grown pea cultivars.

2. To determine the true ileal amino acid digestibilities in Manitoba-grown peas.

3. To determine the impact of increasing dietary levels of pea on growth performance of nursery pigs.

Procedure and Project Activities:

To address the objectives of the project, three studies were conducted, namely a chemical and nutrient profile assay; a digestibility study; and a growth performance study.

The chemical and nutrient profile determination was done to address objective 1.  Nine pea cultivars (yellow-, and green-seeded) were obtained from the Morden Research Station of Agriculture and Agri-Food Canada and analyzed for chemical composition using standard procedures.  Each sample was analyzed in duplicate for dry matter, crude protein, fat, fibre components (NDF and ADF), starch, and non-starch polysaccharides (NSPs).

In the digestibility study, the apparent, standardized and true ileal digestibilities of amino acids and protein in three pea cultivars and in a diet containing a mixture of three pea cultivars (i.e. AC Melfort, CDC Mozart, and Eclipse; all obtained from the Morden Research Station) were determined using growing pigs (average initial body weight of 24.4 ± 1.8 kg (mean ± SD)).  The pigs were surgically fitted with a simple T-cannula (20 mm i.d.; Department of Agricultural Engineering, University of Guelph) at the end of the small intestine to allow collection of the digesta used in ileal digestibility determinations. 

To determine the amount of pea that can be included in diets for weaned pigs without compromising performance, a growth performance trial with ninety-six Cotswold piglets with a mean initial body weight of 6.05 ± 1.08 kg (mean ± SD) and weaned at 17±1 days (mean ± SD) of age was performed.  The 5 dietary treatments included a corn-soybean meal (control) and 4 diets containing graded levels (i.e. 15, 20, 25, and 30%) of pea (cv. Swing) included at the expense of corn and soybean meal.  Diets were formulated to similar nutrient levels and to meet nutrient requirements for phase 1, 2, and 3 nursery pigs and fed as pellets.  Phase 1 diets were fed from day 21 to 28, while phase 2 and 3 were fed from day 29 to 42 and day 43 to 56, respectively.  Weekly body weight per pig and mean pen feed intake was recorded.  Feed conversion efficiency (gain:feed ratio) was obtained from the measurement of daily feed intake and weight gain per pen.

Results and Discussion:

The average chemical and nutrient profile of the nine pea cultivars evaluated is shown in Table 1.  Crude protein, starch and non-starch polysaccharides averaged 22.1% (range 20.0 to 24.2%), 385 mg g^-1 (range 331 to 428), and 87.7 mg g^-1 (range 75 to 104) among the cultivars.  Overall, the average content of the various parameters agrees well with previous reports except that in the cultivars evaluated here the levels of neutral detergent fibre and starch were considerably lower.  The crude protein content in the green cultivars averaged 23.5% (dry matter basis), which was lower that the 25.7% level seen in yellow-seeded varieties.  The lower starch content (43% compared to 54% reported previously) observed in the cultivars evaluated in the current study could imply lower digestible energy content for swine.

Table 1.  Cotyledon color and average chemical composition (%) of pea cultivars (as is)

 * Number of cultivars analyzed.

The amino acid lysine is an essential amino acid and often the first limiting in pig feeds.  Table 2 shows the apparent, standardized and true ileal lysine digestibility in the pea diets evaluated.  The digestibilities of the other essential amino acids are shown in Tables 3, 4, and 5. Apparent ileal amino acids digestibilities of the essential amino acids were not different among diets only for phenylalanine; for standardized ileal digestibilities, this was the case for Phenylalanine and leucine only.  Overall apparent and standardized ileal amino acids digestibilities were 74.8% and 81.1%, respectively.  True ileal amino acid digestibilities were similar among diets except for lysine, phenylalanine and valine.  Overall true digestibility for the determined essential amino acids was 93.6%.  The overall apparent and true digestibilities of lysine in peas were similar to the values reported for soybean meal, further demonstrating the high quality of pea protein for pigs.

Table 2.  Apparent, standardized, and true ileal lysine digestibility (%) in pea-based diets fed to growing pigs.

 * Mixture of peas contains AC Melfort, CDC Mozart, and Eclipse varieties.

** SEM, pooled standard error of the mean.

^a,b Within  a column, means without a common superscript letter differ (P < 0.05).

Table 3.  Apparent ileal protein and essential amino acid digestibilities (%) in pea-based diets fed to growing pigs.

* Mixture of peas contains AC Melfort, CDC Mozart, and Eclipse varieties.

Table 4.  Standardized ileal protein and essential amino acid digestibilities (%) in a pea-based diet fed to growing pigs.

* Mixture of peas contains AC Melfort, CDC Mozart, and Eclipse varieties.

** SEM, pooled standard error of the mean.

^a,b Within  a row, means without a common superscript letter differ (P < 0.05).

Table 5.  True ileal protein and essential amino acid digestibilities (%) in a pea-based diet fed to growing pigs.