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Latest Developments in Alternative Feedstuffs for Pigs

by 5m Editor
16 July 2007, at 12:00am

By Ruurd T. Zijlstra, University of Alberta and Eduardo Beltranena, Alberta Agriculture and Food Edmonton as presented at the 2007 Manitoba Swine Seminar.

Introduction

Feed cost remains the largest portion of the variable costs in swine production. To control feed cost, swine producers or their nutritionist continue to look for alternative feedstuffs. Reasons to include alternative feedstuffs in swine diets might be a desire to improve pork quality, nutrient management, animal health, or animal welfare. The main criterion for successful incorporation of alternative feedstuffs is digestible nutrient profile. This profile is required for diet formulation and will be a main component of an effort to ensure that growth performance and feed cost per unit of output are maintained. Overall, alternative feedstuffs can be divided into two categories:

  1. feedstuffs that directly result from crop production and
  2. feedstuffs that result from crop fractionation.
The latter category has been referred to as by-products in the past, but is currently referred to as co-products. Some comments will be made about each category.

Crops

Generally, few crops have been developed strictly for the production of livestock feeds. However, a large portion of the crops produced in western Canada end up in livestock feeds. The feed market, however, tends to be lowest priced market for crops. Development of new crops and new alternative ingredients should therefore bring a clear benefit to the crop producer beyond the price that the producer can fetch for the feedstuffs. Such benefits could be an increased yield relative to other crops under the same conditions or improvements in nitrogen fixation. An example of such crop that comes to mind for swine is the zero-tannin faba bean.

The zero-tannin faba bean provides a yield benefit over field pea under specific conditions such as temperatures that are not too hot and good moisture conditions. Furthermore, the zero tannin faba bean fixates more nitrogen and for longer period than pea in the growing season, resulting in a higher crude protein content in the harvested beans. Similar to other legume seeds, the faba bean contains anti-nutritional factors (ANF). In legume seeds, common ANF are trypsin inhibitors, lectins, and tannins. In regular faba beans, the tannins are the most common and troublesome ANF (Jansman 1993). Advancements in crop breeding in Europe have resulted in the creation of zerotannin faba beans, which are cultivars that contain 1% or less of condensed tannins, which are primarily concentrated in the hull (Jansman et al. 1995).

Alberta Agriculture has led the efforts to further enhance the cultivation of zero-tannin faba bean. In Europe, similar efforts were conducted to reduce the dependence on imported soybean meal and the stimulation of the local production of legume or pulse seeds, such as pea, faba bean, chick pea, and lentil, etc. These efforts started with the introduction of the crop and by conducting experiments to characterize the digestible nutrient profile and to replace soybean meal as a protein source in diets fed to growerfinisher pigs (Zijlstra et al. 2004).

Faba bean (Vicia faba minor) production is not new to Alberta. Research was completed in the early 1970’s; however, tannin and other anti-nutritional factors limited the use of faba bean in swine diets. The general purpose of the new projects such as Zijlstra et al. (2004) was to remove barriers, which were preventing increased production and use of zero-tannin faba bean in Alberta, especially in the Parkland and Peace River regions. Analysis of the nutrient content of zero-tannin faba bean and a subsequent performance study were thus needed. Objectives were (1) to determine chemical characteristics, energy and amino acid (AA) digestibility, the content of DE and NE, and tannin content of zero-tannin faba bean; and (2) to compare growth performance variables and carcass quality of grower-finisher pigs fed zero-tannin faba beans to soybean meal.

Energy and amino acid digestibility were determined using 60-kg cannulated barrows. Energy digestibility was tested in a diet containing 96% faba beans. Amino acid digestibility was tested in a diet containing 62% faba bean and 35% cornstarch. In a subsequently growth performance study, 100 grower-finisher pigs in 20 pens had free access to either a soybean meal or faba bean-based diet regime from 30 to 115 kg. Diets were formulated to equal NE and SID (Grower (30-60 kg), 2.40/3.95; Finisher I (60-90 kg), gilts 2.38/3.15, barrows 2.38/2.76; Finisher II (90-115 kg), gilts 2.38/2.92, barrows 2.35/2.55; Mcal/kg NE/g SID lysine/Mcal NE, respectively), including up to 30% faba beans.

Table 1. Characteristics of zero-tannin faba bean
Item % as fed
Nutrient
Moisture 13.4
Crude protein 27.5
Acid detergent fibre 9.6
Neutral detergent fibre 19.8
Crude fat 1.0
Tannin 1.1
Total amino acids
Lysine 1.75
Threonine 0.88
Methionine 0.21
Total sulphur AA 0.56
Tryptophan 0.25

The chemical characteristics suggest that zero-tannin faba bean has a desirable nutrient content (Table 1). The protein content of zero-tannin faba bean is slightly better than pea (NRC 1998). The digestible nutrient profile is similar to field pea for energy and slightly higher for amino acids (Table 2). Overall, ADG and ADFI (data not shown) did not differ between zero-tannin faba beans or soybean meal indicating that faba bean inclusion up to 30% is possible without reducing ADG. From the results of the initial experiment, it was concluded that the zero-tannin faba bean is a worthwhile protein ingredient to consider as a replacement for soybean meal.

Table 2. Digestible energy and amino acid profile of zero tannin faba bean
Item % as fed
Energy
Ileal digestibility, % 60.2
Ileal digested energy, kcal/kg 2,362
Total tract digestibility, % 88.5
DE content, kcal/kg 3,471
NE content, kcal/kg 2,267
Apparent amino acid digestibility, %
Lysine 85.9
Threonine 76.1
Methionine 74.1
Tryptophan 76.4
Standardized ileal digested AA content, %
Lysine 1.54
Threonine 0.70
Methionine 0.16
Tryptophan 0.20

The initial experiments were recently followed with additional growth performance experiments in the nursery (Omogbenigun et al. 2006) and a commercial-scale field trial (Gunawardena et al. 2007). We have confirmed that the zero-tannin faba bean may be included in late nursery diets up to a level of 40% without detrimental effects on weaned pig performance. We have also confirmed that ZT fababean can fully or partially replace locally-grown pea or imported soybean meal as dietary supplemental protein source without negative effects on live hog performance, carcass characteristics, pork quality, tissue yield on primal cuts or lean yield expressed as a proportion of cold carcass side.

Co-Products

Crop fractionation is the separation of grain stock into two or more fractions. Historically, fractionation of western Canadian crops has been conducted by placing the entire grain stock into a process, resulting in the production of a main fraction, and one or more co-products, previously labeled as by-products. The production of canola oil and canola meal from canola seed, ethanol and wheat distiller’s grain plus solubles (DDGS) from wheat, flour and wheat millrun from wheat, and beer and brewer’s grain from barley are such examples. Traditionally, fractionation of crops has resulted in a higher net income to the crop producer than merely production of crops for feed purposes.

As benefit of crop fractionation is that a larger array of co-products are becoming available for inclusion in feeds. The use of co-products has been adopted globally on a large scale. In western Canada, the use of co-products in feeds has been adopted reluctantly because grains could be included in feeds competitively. However, this scenario is changing rapidly with the emergence of increased fractionation capacity in western Canada driven by bio-fuel production. Instead of feed, bio-fuel production may drive pricing if commodities. As a result, feed grains will become relatively more expensive, and the inclusion of existing or new co-products in feed is becoming an economic necessity to remain competitive.

With the recent increase in feed grains prices, co-products such as wheat co-products from dry milling, wheat and corn distiller’s dried grain with solubles (DDGS), and canola meal should receive serious consideration for inclusion in swine diets. Historically, milling and crushing industries and more recently the biofuel industry have expanded. The volumes of co-product continue to increase, especially high protein co-products, whereas the production of stock crops has not kept pace. Feedstock purchases by the bio-fuel industry will result in less crops being available as livestock feedstuffs. As a combined result, protein co-products have become more competitive for inclusion into swine diets.

Wheat co-products from either the milling or ethanol industry generally have less starch than the wheat of origin and contain more fibre or non-starch polysaccharides, protein, and fat (Nyachoti et al. 2005; Widyaratne et al. 2007; Nortey et al. 2007). Co-products from dry milling would also contain more phytate (Nortey et al. 2007); however, phytate content is less in wheat DDGS than wheat (Widyaratne et al. 2007), indicating that phosphorus digestibility in wheat DDGS is enhanced. For wheat co-products from dry milling such as millrun, middlings, shorts, and bran, the increased NSP and phytate content indicate that NSP- and phytate-degrading enzymes will provide a benefit to increase nutritional value.

The specific effects of xylanase and phytase on diets containing wheat millrun have been researched (Nortey et al. 2007). Millrun is a combination of individual co-products stream, and for his study contained shorts, bran and screenings. Effects of millrun inclusion rates (20 or 40%), xylanase (0 or 4,375 units/kg feed), and phytase (0 or 500 phytase units/kg feed) on nutrient digestibility and growth performance were investigated in a 2 x 2 x 2 factorial arrangement with a wheat control diet (0% millrun). Diets were formulated to contain 3.34 Mcal DE/kg and 3.0 g true ileal digestible Lys/Mcal DE.

For this experiment, diets containing millrun had a reduced DE even though diets were formulated to an equal DE content. The results indicate that knowledge about the accurate nutritional value of wheat co-products is limited. For the diet containing 20% millrun, xylanase plus phytase improved DE content from 3.53 to 3.69 Mcal/kg DM, a similar DE content as the wheat control diet (3.72 Mcal/kg DM). These results indicate that enzyme supplementation in combination with the use wheat co-products is a welcome alternative to sole dependence on feed grains.

Further experimentation is focused on the better characterization of co-products. Overall, ingredient fractionation by the processing industry will produce co-products that will become an attractive feedstuff for the large volume, small margin markets of feedstuffs and feeds for grower-finisher pigs and sows. However, ingredient fractionation also provides opportunities for the small volume, higher margin markets for feedstuffs and feeds for starter pigs.

Summary and Conclusions

Changes in the crop and processing industries may lead to new feedstuffs becoming available. Any feedstuffs should be considered as an alternative feedstuff in feed formulation, provided sufficient information on digestible nutrient profile is available. Especially during times with high prices of traditional feedstuffs, alternative feedstuffs might provide an opportunity for swine producers to control feed costs. Opportunities to develop alternative feedstuffs will become increasingly important to improve the competitiveness of the western Canadian crop and livestock industries.

References

Gunawardena, C., W. Robertson, M. Young, R.T. Zijlstra, E. Beltranena. 2007. Zerotannin fababean, field pea and soybean meal as dietary protein sources for growingfinishing pigs. J. Anim. Sci. 85 (Suppl. 2). (In Press)

Jansman, A.J.M. 1993. Tannins in feedstuffs for simple-stomached animals. Nutr. Res. Rev. 6:209-236.

Jansman, A.J.M., M.W.A. Verstegen, J. Huisman, J.W.O. van de Berg. 1995. Effects of hulls of faba beans (Vicia faba L.) with a low or high content of condensed tannins on the apparent ileal and fecal digestibility of nutrients and the excretion of endogenous protein in ileal digesta and feces of pigs. J. Anim. Sci. 73:118-127.

Nortey, T.N., J.F. Patience, P.H. Simmins, N.L. Trottier, R.T. Zijlstra. 2007. Effects of xylanase and phytase supplementation on energy, amino acid, and phosphorus digestibility and growth performance of pigs fed wheat-based diets containing wheat millrun. J. Anim. Sci. (In Press)

Nyachoti, C.M., House, J.D., Slominski, B.A. and Seddon, I.R. 2005. Energy and nutrient digestibilities in wheat dried distillers’ grains with solubles fed to growing pigs. J. Sci. Food Agric. 85:2581-2586.

Omogbenigun, F.O., R.T. Zijlstra, E. Beltranena. 2006. Inclusion of Zero-Tannin Fababean and Substitution for Soybean meal in Nursery Diets on Weaned Pig Performance. J. Anim. Sci. 84 (Suppl. 2):94-95.

Widyaratne, G.P., R.T. Zijlstra. 2007. Nutritional value of wheat and corn distiller’s dried grain with solubles: digestibility and digestible contents of energy, amino acids and phosphorus, nutrient excretion and growth performance of grower-finisher pigs. Can. J. Anim. Sci. (In Press)

Zijlstra, R.T., K. Lopetinsky, B. Dening, G.S. Bégin, J.F. Patience. 2004. The nutritional value of zero-tannin faba beans for grower-finisher pigs. Can. J. Anim. Sci. 84:792-793.

July 2007

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