J APPL POULT RES 2008. 17:522-528. doi:10.3382/japr.2008-00004
© 2008 Poultry Science Association
Inclusion of Buckwheat in Organic Broiler Diets
J. P. Jacob1 and
C. A. Carter
University of Minnesota, Department of Animal Science, 1364 Eckles Ave., St. Paul 55108
1 Corresponding author: jacquie.jacob{at}uky.edu
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SUMMARY
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Many smaller farms in the United States are switching to organic crop production to remain competitive in an era of industrial agriculture. In doing so, they are cultivating crops not traditionally grown in the area. In the US Midwest, a popular organic crop is buckwheat. As organic corn continues to increase in price, many organic poultry farms are using alternative grains in their poultry diets, including buckwheat. Although buckwheat has been used as a livestock and poultry feed for many years, there are very few published data available on its use. The purpose of this study was to evaluate the use of buckwheat as the main ingredient in organic broiler diets. Four experimental diets were used, with varying levels of buckwheat: 0, 20, 40, and 60%. The results indicated that up to 60% buckwheat can be included in broiler diets with no significant effect on BW gain. With the 60% inclusion level, however, there was a significant decline in feed efficiency. As the price of organic corn continues to increase, the lower price for buckwheat may make it an economical substitute in organic broiler diets.
Key Words: buckwheat • organic • broiler
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DESCRIPTION OF PROBLEM
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Crop rotation is an essential tool for management of weeds and other pests in organic systems. The weed cycle can be disrupted by introducing a fast-growing smother crop, such as buckwheat (Fagopyrum sagittatum), into the rotation [1]. Buckwheat has long been used as a livestock and poultry feed [2], but unfortunately, very few published data are available on its use. The literature suggests that buckwheat has reasonable feed value, roughly comparable to oats [1]. The grain is reported to contain 11 to 13% CP and is high in lysine, an essential amino acid that most grains are deficient in (0.61% as compared with 0.26% for corn, 0.31 to 0.37% for wheat, and 0.29 to 0.40% for barley) [3].
There are some reports on buckwheat use in swine diets, another nonruminant species. In a field trial comparing organic and conventional swine diets in an open-front shed housing system, no major differences were observed. The pigs fed the organic diet, which had 25% buckwheat, had a slightly greater average daily BW gain compared with the pigs fed the conventional diet [4].
It is becoming more difficult to find certified organic corn and soybean meal (SBM). As a result, organic producers are looking toward other crops to replace these conventional feed ingredients. In addition, a concern for rising corn prices is pushing all livestock producers to find an alternative to corn. The US organic regulations, set by the National Organic Standards Board, do not allow for the inclusion of synthetic methionine, an ingredient routinely added to conventional poultry diets. Organic poultry producers have had a transition period since the organic regulations were first put into place to find alternatives to synthetic methionine, and the ban on synthetic methionine is scheduled to come into effect October 1, 2010 [5]. Organic poultry producers are in search of alternative feed ingredients that, when used in poultry diets, eliminate the need for methionine supplementation.
The purpose of this research was to evaluate the use of buckwheat as a substitute for corn in organic broiler diets formulated without synthetic methionine.
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MATERIALS AND METHODS
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The feeding trial was run in March and April of 2007. Temperature was recorded using a data logger placed in each of the 3 rooms used in the trial.
Diet Formulation
There were 4 experimental diets with different levels of inclusion of buckwheat: 0, 20, 40, and 60% of the diet. The nutrient content of the main ingredients used in this study are shown in Table 1
. According to Dale and Batal [6], the ME content of corn, expeller-extracted SBM, and buckwheat is 3,390, 2,420, and 2,640 kcal/ kg, respectively. These values, including that of buckwheat, were confirmed in TME trials conducted before this study. Nutritionally, buckwheat is greater in protein than corn but is lower in ME. Similarly, buckwheat is lower in protein than mechanically extracted SBM but slightly greater in ME. Buckwheat has greater levels of the sulfur amino acids than corn, but as would be expected, has considerably lower levels than SBM. Although buckwheat contains less methionine than corn, when expressed as a percentage of total protein, methionine is greater in buck-wheat.
Many organic broiler growers in the American Midwest use a single broiler feed from start to finish, especially if they are located a considerable distance from a source of organic feed. Similarly, in this study, the broiler chickens received the same diet throughout the 42-d growing period. The nutrient specifications were based on NRC requirements for broiler starter diets [3].
The experimental diets were formulated to contain similar energy and amino acid levels. The target ME levels were 2,644 kcal/kg, and the dietary levels of other nutrients were adjusted to this energy level (Table 2). Most organic feed mills in the American Midwest are unable to formulate diets to the conventional 3,200 kcal/ kg of ME, because animal fat is not allowed in organic diets. Molasses was used as an energy source in the experimental feeds. The composition of the diets, and nutrient content, are shown in Table 3. As the level of buckwheat in the diet increased, the level of SBM and flax inclusion decreased. It was difficult to formulate diets that were identical in energy and amino acid levels. Energy values ranged from a low of 2,598 kcal/ kg for diet 4 to a high of 2,690 for diet 1, less than a 3.5% difference in calculated dietary energy. Similarly, the diets were formulated to have similar levels of the sulfur amino acids. To achieve the required dietary amino acid levels without the use of synthetic methionine, greater total CP levels were required at lower levels of buckwheat inclusion.
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Table 2. Nutrient requirements used in formulation of the experimental diets determined by adjusting NRC [3] requirements to a lower dietary energy content
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Table 3. Composition and nutrient content of the experimental diets (formulated to a target dietary energy content of 2,644 kcal/kg)
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All diets were fed as a mash. Feed was provided in round hanging feeders filled manually. The feed tended to bridge in the feeders, so the feeders were shaken daily to ensure a constant supply of feed throughout the trial. The flow problems may be related to bulk density. Although buckwheat and corn have similar bulk densities, both are lower than soybean meal. As the percentage of buckwheat in the diet increased, the level of SBM decreased.
Birds and Housing
One-day-old male Cornish-cross chicks were purchased from a local hatchery [7] where they were vaccinated for Marek’s disease before shipment. The chicks were housed in floor pens 3 x 6 ft, with 15 chicks per pen. There were 4 diets and 6 replications per diet, totaling 24 pens. The pens were divided among 3 rooms, and there were 2 replications of each diet in each room resulting in a randomized block design. All the chicks received 23 h of light daily.
The chicks received all experimental diets and water ad libitum for 6 wk. Each week, the chicks were individually weighed to calculate average pen weight. Feed consumption for each pen was measured weekly, and consumption per broiler was calculated based on weekly chick days. Mortality was recorded twice daily.
Statistical Analysis
Data were analyzed by using Statistix 8.0 software [8]. The individual BW were analyzed with Stem-Leaf Plot to remove outliers. The remaining BW were analyzed as a randomized complete block design. Body weight gain and feed consumption were calculated weekly with the pen means being the experimental unit. The BW gain, feed consumption, and feed conversion data were analyzed as a randomized complete block design. Differences between means were determined using Tukey’s test. Polynomial contrasts were run to determine the existence and nature of trends in the level of buckwheat in the diet.
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RESULTS AND DISCUSSION
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When compared with conventional broiler production, overall performance was low for broilers in all of the dietary treatments, achieving less than 1,800 g in 6 wk. The low performance may have been due to the consistency of the feed. The feed was a mash that tended to bridge in the feeders. Pelleting the feed may have decreased this problem, but not all organic feed mills have access to pellet mills. Mortality was low for all treatment groups and occurred primarily in the first 3 wk of the study. Only 1 broiler died after 3 wk of age. There were no significant differences in level of mortality.
The average weekly BW are shown in Figure 1. For each week, there was a significant block x diet interaction. Differences in room temperatures may have contributed to the interaction. In 1 room, there were no significant differences among average BW per pen each week. For the other 2 rooms, however, there were significant differences in BW for wk 1 to 3 or 1 to 5 depending on the room. For all the rooms, however, there were no significant differences in the final BW for the 4 dietary treatments. For wk 1 to 3, there were significant positive linear and quadratic trends.
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Figure 1. Average weekly BW (g) for the broilers on each of the 4 experimental diets. Final average BW were 1,790.4 ± 62.7, 1,741.4 ± 49.0, 1,755.4 ± 35.0, and 1,754.9 ± 39.1 for diets 1 through 4, respectively.
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The average BW gains are shown in Figure 2. There was no significant block x diet interaction on BW gain, nor were there any significant differences among broilers on the 4 diets each week.
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Figure 2. Average weekly BW gains (g) for the broilers on each of the 4 experimental diets. Overall BW gains were 1,751.7 ± 62.5, 1,703.4 ± 48.9, 1,717.0 ± 35.1, and 1,715.9 ± 52.1 for diets 1 through 4, respectively.
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Weekly and overall feed consumption are shown in Table 4. Unlike BW, there was no block x diet interaction affecting feed consumption. Inclusion of buckwheat in the broilers diets resulted in increased feed consumption. The increase was significant in the first 3 wk only. Overall, the inclusion of 60% buckwheat resulted in the greatest feed consumption, which was significantly greater than the consumption of the broilers on the 0 and 20% buckwheat diets. Differences in dietary fiber and fat contents may have contributed to the increased consumption. With the increasing inclusion of buckwheat, there was a decrease in the dietary level of flax. Flax seed has a high fat content, and with decreased inclusion, a lower crude fat content of the diet can be expected. Buckwheat has greater fiber content than corn; the more buckwheat replaces corn, the greater the dietary fiber content.
Weekly and overall feed conversion ratios, expressed as grams of feed per gram of BW gain, are shown in Table 5. Although BW gain was not significantly affected by diet composition, feed consumption increased with increased inclusion of buckwheat, resulting in a decline in feed efficiency.
Buckwheat is a good cover or rotational crop for organic farms. It is a relatively low input crop that is able to produce relatively high yields, even in marginal soils. The use of buckwheat in organic crop production has environmental benefits in that it adds nutrients to the soil [9]. With the potential of buckwheat as an ingredient in organic poultry diets, its production can be expected to increase.
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CONCLUSIONS AND APPLICATIONS
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- Buckwheat can be included in organic broiler diets with no significant effect on overall BW gain.
- Feed conversion worsens as the level of buckwheat in the diet increases. As the difference between the price of organic corn and buckwheat widens, it will become more economical to use buckwheat despite the decreased feed efficiency.
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ACKNOWLEDGMENTS
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This project was funded by a grant from USDA-Cooperative State Research, Education, and Extension Service. We would like to thank Jeanine Brannon, a technician at the University of Minnesota, Department of Animal Science, who assisted with the analyses of this project. We would also like to thank the Buckwheat Growers Association of Minnesota (Wadena) for their assistance in mixing the diets.
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REFERENCES AND NOTES
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- Cheeke, P. R. 1991. Applied Animal Nutrition: Feeds and Feeding. MacMillan Publishing Co., New York, NY.
- Myers, R. L., and L. J. Meinke. 1994. Buckwheat: A Multi-Purpose, Short-Season Alternative. Publication G4306. University of Missouri, Columbia.
- NRC. 1994. Nutrient Requirements of Poultry. 9th rev. ed. Natl. Acad. Press, Washington, DC.
- Koehler, B. 2002. Organic Hog Production Using Several Organic Feed Diets. Research report. Southwest Research and Outreach Center (SWROC) of the University of Minnesota. http://swroc.cfans.umn.edu/Bob/docs/finalsar-ereport.PDF Accessed Sept. 13, 2008.
- USDA/AMS National Organic Program. 2008. NOSB recommended decision form: Methionine. http://www.ams.usda.gov/AMSv1.0/getfile?dDocName=STELPRDC5070353&acct=nosb Accessed July 2008.
- Dale, N., and A. Batal. 2006. Ingredient analysis. In 2007 Reference Issue and Buyers Guide. Feedstuffs 78:16–23.
- Welp Hatchery, Bancroft, IA.
- Statistix. 2003. Version 8.0. Analytical Software, Tallahassee, FL.
- Huntrods, D. 2007. Buckwheat profile. http://www.agmrc.org/agmrc/commodity/specialitycrops/buckwheat/buckwheatprofile.htm Accessed July 2008.
- Product of Super Gro of Iowa Inc., Aplington, IA.
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SUMMARY
DESCRIPTION OF PROBLEM
