Testing the quality of corn that has been selected for organic poultry

Why breed corn with greater concentrations of methionine and carotenoids?

Amino acids are the building blocks of proteins, which are the building blocks of our bodies. Methionine is an essential amino acid that animals and humans cannot synthesize themselves, so they need to obtain it from the diet for normal growth and development. Poultry have high demands for methionine. Low quantities limit their growth and reduce health and egg production.

Carotenoids are yellow to orange pigmented substances that occur naturally in the plant kingdom. They are rich in antioxidants. Carotenoids such as Lutein and zeaxanthin are important for eye health, whereas beta -carotene and beta-cryptoxanthin are used by our bodies to make Vitamin A, which is also important for eye health. Antioxidants from plants help to prevent aging and to maintain good body function and overall health. Both methionine and carotenoids are powerful antioxidants.

Carotenoids in eggs convey an orange yellow color to yolks.  These substances may have multiple beneficial effects on human health (Dansou et al., 2023). Orange yolks in eggs and orange skin in broilers are desired by many consumers for health reasons (Altman et al., 2023; Heinzl, 2021), and that affects price. As egg yolk color is one of the most important measures of egg quality by consumers, (Heinzl, 2021) their color is generally monitored through visual scoring. The orange color can be increased by feeding corn with a high carotenoid content.

Quantities of methionine are often insufficient in poultry feed. Because corn often constitutes 60% of poultry diets, corn bred with more methionine would reduce dependence on expensive soybean, sunflower meal, or synthetic methionine.  Synthetic methionine is a controversial input used in regulated quantities by organic poultry farmers.  The National Organic Standards Board of the USDA permitted continued use of synthetic methionine in 2016, but it also recommended finding replacements for synthetic methionine as its first research priority (NOSB, 2018).  This included researching systems approaches to feeding animals and the development of high methionine corn as an alternative.

Methionine is the first limiting amino acid and lysine is the second limiting amino acid in poultry diets (NRC 1994). For more information on methionine and poultry and the amounts of methionine in common feedstuffs, see the eOrganic article Synthetic Methionine and Organic Poultry Diets at https://eorganic.org/node/7902.

Evaluating corn with high methionine and carotenoids

The Mandaamin Institute (Elkhorn, WI) bred hybrids with high methionine and carotenoid content (Goldstein et al, 2012; 2019; Goldstein 2022; Goldstein, 2022). Methionine in Mandaamin corn generally contains 0.24 to 0.28% on a dry matter basis while conventional corn generally has 0.16 to 0.21% (Goldstein et al. 2008, 2019, and Jaradat and Goldstein, 2013, 2014; 2018).  Preliminary feeding trials showed no significant differences in broiler (meat bird) or layer production if high methionine corn from the Mandaamin program were substituted for conventional corn + methionine (Jacob et al., 2008; Goldstein et al., 2012).

It is important for farmers and feed companies to assess the relative productivity of these high-quality corn varieties to understand their place in the market.  Several of these Mandaamin Institute-bred hybrids were compared with commercial hybrids in a NIFA OREI-funded project in 2018 and 2019. Strip trials were planted on 13 farm sites in the Central (IL, IN) and on 13 sites in the Northern Corn Belt (WI) regions. Each site is a replicate.

Two Mandaamin hybrids were grown on each of these sites. These were 17.C46 with a relative maturity (RM) of 105 days, and 17.C2B2 with a RM of 110 days. The commercially available check (control variety representative of normally used, organic corn) in the Central Corn Belt for both years was Great Harvest 59R5 (RM 109 day) from Beck’s Hybrids, Atlanta, IN. The commercial checks for the Northern Corn Belt were FOS8507 from Foundation Organic Seed, Onalaska, WI (RM 108 day) in 2018 and FOS8500 (RM 105 day) in 2019.

Grain was harvested for yield and analyzed at the University of Illinois in Urbana-Champaign for macronutrients, Iowa State University Grain testing lab for amino acid content, University of Wisconsin for carotenoids, and by a commercial lab for minerals. The data were analyzed using analysis of variance with main factors being regions and hybrids and with farm sites as replicates. Where differences between hybrids were statistically significant, we compared them with t-tests.

Results and Discussion

As shown in Table 1, yields were similar among the three hybrids.  Though the difference in yield between the hybrids was not statistically significant, 17.C46, which was the earliest maturing hybrid, yielded less in the fuller season, Central Corn Belt sites and the 17.C2B2 averaged 10% less yield than the checks over all sites. These yield calculations were based on a 56 pound per bushel test weight. However, the Mandaamin hybrids had lower test weights and seed density because they are softer, floury texture. But they had 10 to 18% more protein, 32% more oil, 44 to 63% more zeaxanthin, 48 to 150% more β-cryptoxanthin, 38 to 65% more β-carotene, 10 to 15% more lysine, 33 to 42% more methionine, and 10 to 16% more cysteine in their grain than did the commercial checks. These differences were all statistically significant at the 95% security level. They also had 23 to 25% higher methionine contents in their protein than did the checks. Furthermore, mineral analysis revealed that the Mandaamin hybrids had 17 to 24% more iron, 22 to 32% more manganese, 13 to 54% more copper, and 11 to 12 more zinc in their grain than did the checks.

Corn grown in WI had higher yields, oil, lutein, lysine in grain, and in protein. Corn grown in IL and IN had higher density, starch, test weight, β-cryptoxanthin, methionine in grain and in protein. There was an interaction between the planting zones and the varieties only for test weight.

In summary, the high methionine and carotenoid corn differed from commercial checks by delivering significantly more methionine, carotenoids, and trace minerals at comparable yield levels.

Table 1. Results from trials on 26 sites

Parameter		Hybrid averages				Comparisons
		17.C46	17.C2B2	Checks		17.C46 / check	17.C2B2 / check	17.C46 / 17.C2B2
	Unit	averages				--% difference--
Yield IL, IN	bu./ac	109	120	134		-18	-10	-9
Yield WI	bu./acre	139	142	159		-12	-11	-2
Yield average	bu./acre	124	131	146		-15	-10	-5
Test weight	lbs/bu.	55	54	58		-5	-6	1
Density	g/cm3	1.15	1.15	1.23		-7	-7	0
Starch	%	69.4	70.0	72.4		-4	-3	-1
Protein	%	9.0	8.4	7.6		18	10	7
Oil	%	4.8	4.8	3.7		32	32	0
Lutein	µg/g	5.32	5.72	4.65		14	23	-7
Zeaxanthin	µg/g	1.51	1.70	1.04		44	63	-11
β-cryptoxanthin	µg/g	0.75	1.26	0.51		48	150	-41
β-carotene	µg/g	0.55	0.66	0.40		38	65	-16
Lysine in grain	%	0.31	0.29	0.27		15	10	4
Lysine in protein	%	3.69	3.85	3.70		0	4	-4
Methionine in grain	%	0.27	0.25	0.19		42	33	7
Methionine in protein	%	3.20	3.24	2.60		23	25	-1
Cysteine in grain	%	0.20	0.19	0.17		16	10	5
Cysteine in protein	%	2.36	2.45	2.35		0	4	-3
Comparison % values in bold with enlarged numbers are statistically significant at the 95% security level.

Organic maize as a source of methionine

Methionine is the major limiting ingredient for organic poultry production (Goldstein et al., 2008; Fanatico and Ellis, 2016). Organic poultry producers are allowed by USDA regulations to utilize two pounds of synthetic methionine per ton of feed over the lifetime of layers, but these guidelines should sunset in 2028.

The Methionine Task Force is a consortium of organic poultry producers that represents approximately 80% of the organic layer production in the country. On August 20^th, 2019, the above-described results were sent to Mr. David Will, Chino Valley Ranchers, who chairs the Task Force. According to Mr. Will, the results were circulated to Task Force members; high methionine corn is a potential source of methionine for organic poultry and a feeding trial is being planned. We requested that he query the Task Force members with longer term questions:

1. How do you expect the extra nutrients in the tested hybrids (methionine, carotenoids, minerals) would affect feed formulation and cost for your operation? 
2. What would be the right price for such corn relative to normal corn? 
3. How do you expect using such corn would affect your poultry product quality/value/price?
4. Would you be interested in trying this corn for a feeding trial and if so, how much would you need?

Mr. Will responded later in 2019 that these questions were discussed by task force members, and feeding trials would be necessary to answer the questions. Mr. Will was approached again in the Fall of 2022 to see if the Task Force was ready to conduct larger scale feeding trials with larger quantities of corn from a cooperating organic farmer.  According to Mr. Will the Task Force was not presently ready but might be willing to do trials in the future. 

The consulting company Alltech utilizes linear models to plan rations for organic and conventional farms in the Wisconsin area. Pierre Meyer from Alltech modelled three rations utilizing corn, soybean meal, and synthetic methionine with approximately the same protein and energy levels. The variants were:

• Conventional feed diet: including conventional corn and two pounds per ton of feed of synthetic methionine so that total methionine levels were set at 0.39%.
• High methionine corn diet 1 (Hi Met 1): a low synthetic methionine diet (1.2 pounds of synthetic methionine/ton of feed) that includes high methionine corn and a total methionine level of 0.39%.
• High methionine corn diet 2 (Hi Met 2): a diet with high methionine corn and no synthetic methionine added, where total methionine levels are set at 0.33%. This is approximately the level set for methionine need by the National Research Council. The amounts needed to feed poultry can be found in the NRC guidelines (NRC 1994) and are generally lower than those used by industry.

The results of the modelling exercise are described in Table 2.

Table 2. Modelled rations (Meyer, Alltech) and costs for a balanced ton of feed for layer production.

Feed Ingredient	Conventional		Hi Met 1		Hi Met 2
	0.39% Methionine		0.39% Methionine		0.33% Methionine
	lbs	$	lbs	$	lbs	$
Corn	1,197.5	195.45	0.0	-	0.0	-
Soybean Expeller BH	580.5	464.40	537.4	429.92	540.0	432.00
Lime F	220	4.40	220	4.40	220.0	4.40
Corn High methionine	0	-	1,241.4	202.61	1,240.0	202.39
Synthetic methionine	2	5.74	1.2	3.44	0.0	-
Total	2,000	669.99	2,000	640.37	2,000	638.79
Corn values for feeding were adjusted for test weights figured at 56 lb/bu for conventional corn; 54 lb/bu for high methionine corn
Parameter	bu corn	$/bu	bu corn	$/bu	bu corn	$/bu
Bushels needed & price per bushel	21.4	9.14	23.0	8.81	23.0	8.81
Ration value difference from conventional		0		29.61		31.20
Potential premium per bushel				1.29		1.36
Potential value per bushel		9.14		10.10		10.17

The two alternative feeds that included high methionine corn were $29.61 and $31.20 cheaper than the conventional ration. Based on bushel weight, this meant a potential premium of up to $1.29 or $1.36/bushel for sold corn. This premium represents 11% more than for conventionally bred organic corn and appears to be approximately equivalent to the yield reduction associated with the best yielding of the Mandaamin corn. The calculated value associated with methionine corn shown for the High Meth 3 diet is shown in Table 3.

Table 3. Calculated value associated with methionine corn shown for the High Meth 2 diet. The value of crop for layers assuming savings in feed are transferred to grain price.

Site	17.C46	17.C2B2	Check	17.C46	17.C2B2	Check
	bu/acre based on test weight			$/acre
IL, IN	113.0	124.4	134.0	1,150	1,361	1,225
WI	144.1	147.3	159.0	1,466	1,498	1,453
Average	128.6	135.9	146.5	1,308	1,382	1,339

The higher premium and the differences in the value of the crop based on these scenarios may not be sufficient to convince large numbers of organic farmers to grow high methionine corn. It remains unclear whether synthetic methionine will be phased out of organic rations in the future. Continued use of synthetic methionine by organic poultry producers will be reviewed again in 2028 by the USDA National Organic Standards Board (NOSB).  Feeding synthetic methionine to organic poultry is not accepted and contested by some consumer groups (Kerrigan, 2015; Bunin et al., 2015). In 2015, The Organic Consumers Association presented a petition against permitting the use of synthetic methionine to the NOSB with seventeen thousand signatures (Kerrigan, 2015). It therefore seems possible that eggs from birds raised with no synthetic methionine in their feed could potentially bring a higher price from some consumers.

In 2022 and 2023, Organic farmers who attempted to sell high methionine grain to various organic feed mills informed the author that they were not successful at obtaining a premium.  Several confidential conversations by the author with organic feed company representatives in 2021 and 2022 indicated that fear of setting precedence might be an issue. Accepting high methionine corn might lead to further restrictions by USDA in permitted use of synthetic methionine for organic production.  However, in 2023 the Mandaamin corn hybrids have been commercialized and sold by the Foundation Direct Seed Company in Onalaska, WI and are being grown by multiple farmers in different states. So grain might be available for feed trials if there is interest from the organic poultry sector.

Aside from methionine, our calculations do not take into consideration any extra value for poultry or human health, reliability of production, and product quality associated with other components of the high methionine corn. Additional carotenoid and mineral content might have other beneficial consequences. For example, natural carotenoids have been found to foster layer health, performance, and egg quality (Fitri et al., 2023). Although preferences for egg color vary from country to country (Heinzl, 2021), consumers often tend to prefer more orange yolks (Hui, 2016; Heinzl, 2021). 

The data shows that high methionine corn has real potential for organic farmers.  However, greater commercial and social interest are needed to accelerate the testing of this alternative. Further research should include not only larger scale feeding trials but also more definitive determination of available methionine, total protein and metabolizable energy values of the final diets and their effect on overall health and performance of birds. 

References and Citations

• Altman, B.A., A. Trinks, D. Moerlein. 2023. Consumer preferences for the color of unprocessed animal foods. Food Science 88(3):909-925.
• Bunin, L.J., P.M. Tomaselli, C. Harsch, M.L. Crouch. 2015. Center for Food Safety Comments to the NOSB. [Online]. (Available at: https://www.centerforfoodsafety.org/files/center-for-food-safetys-comments-to-nosb-april-7-20151_63311.pdf) (verified 5 Sept 2023).
• Dansou, D.M, H. Zhang, Y. Yu, H. Wang, C. Tang, Q. Zhao, Y. Qin, J. Zhang. 2023. Carotenoid enrichment in eggs from biochemistry perspective. Animal Nutrition 14:315-333. (Available online at: https://doi.org/10.1016/j.aninu.2023.05.012)(verified 5 Sept 2023).
• Fanatico A. and Ellis K.2016. Organic poultry production, providing adequate methionine. [Online]. ATTRA. (Available at: https://attra.ncat.org/publication/organic-poultry-production-providing-adequate-methionine/)(verified 5 Sept 2023)
• Fitri, Y., J. Anuraga, U.Niken. 2023. Performance, egg quality, and immunity of laying hens due to natural carotenoid supplementation: A meta-analysis. Food Sci Anim Resour 2023;43(2):282-304. (Available online at: https://doi.org/10.5851/kosfa.2022.e76)(verified 5 Sept 2023).
• Goldstein, W.A., L.M. Pollak, C. Hurburgh, N. Levendoski, J. Jacob, C. Hardy, M. Haar, K. Montgomery, S. Carlson, and C. Sheaffer. 2008. Breeding maize with increased methionine content for organic farming in the USA. pp 262-275. In: U. Koepke and S.M. Sohn Eds. ISOFAR International Symposium on Organic Agriculture Proceedings. 12-14 March 2008. Dankook University, Korea.
• Goldstein,W.A.,W.Schmidt, H.Burger, M.Messmer, L.M. Pollak, M. E. Smith, M.M. Goodman, F.J. Kutka, and R.C. Pratt. 2012. Maize breeding and field testing for organic farmers. pp. 175-189. In: Organic Crop Breeding. Pub. Wiley-Blackwell, NY.
• Goldstein W., A.A. Jaradat, C. Hurburgh, L.M. Pollak, M. Goodman. 2019. Breeding maize under biodynamic-organic conditions for nutritional value and N efficiency/N2 fixation. Open Agric. 2019; 4: 322–345.
• Goldstein, W. 2022. Testing N efficient, high methionine corn hybrids with organic farmers. [Online}.Final Report USDA-NIFA-SARE project LNC 17-389. (Available at: https://projects.sare.org/sare_project/lnc17-389/)(verified 5 Sept 2023).
• Heinzl, I. 2021.  Appetizing eggs with natural pigmentation.  EW Nutrition, Nov. 10, 2021.  https://ew-nutrition.com/us/appetizing-eggs-natural-pigmentation/
• Hui, A. 2016.  Greater eggspectations. The Globe and Mail. June 2, 2016. (Available online at: https://www.theglobeandmail.com/news/national/different-yolks-for-different-folks-why-we-judge-an-egg-by-itscolour/article30261516/)(verified 5 Sept 2023).
• Jacob, J.P., N. Levendoski, and W. Goldstein. 2008. Inclusion of high methionine corn in organic pullet diets. Journal of Applied Poultry Research. 17:440-445.
• Jaradat, A.A., and W. Goldstein. 2013. Diversity of maize kernels from a breeding program for protein quality: physical, biochemical, nutrients and color traits. Crop Sci. 53:956-976.
• Jaradat, A.A., and W. Goldstein. 2014. Diversity of maize kernels from a breeding program for protein quality: II. Correlatively expressed functional amino acids. Crop Sci. 541-24.
• Jaradat, A., and W. Goldstein. 2018. Diversity of Maize Kernels from a Breeding Program for Protein Quality: III. Ionome Profiling. Agronomy. 2018. 8,9. doi:10.3390/ Agronomy 8020009.
• Kerrigan, P. 2015.  Save organic standards. [Online]. Organic Consumers Association. (Available at: https://organicconsumers.org/report-spring-nosb-meeting-organic-regulatory-theater/)(verified 5 Sept 2023).
• National Organic Standards Board, 2018.  USDA National Organic Standards Board Research Priorities, 2018. [Online]. Available at: https://www.ams.usda.gov/sites/default/files/media/MS2018ResearchPrioritiesRecOct2018.pdf​)(verified 5 Sept 2023).

Funding for this article was provided by the USDA NIFA OREI grant 2017-51300-27115: Participatory Breeding and Testing Networks: A Maize Case Study for Organic Systems, aka the Corn and Soil Health (CASH) project. For more information about this project, see https://eorganic.info/CASH