Comparison of raw, washed and polished quinoa (Chenopodium quinoa Willd.) to wheat, sorghum or maize based diets on growth and survival of broiler chicks 

F Improta and R O Kellems 

Animal Science Department, Brigham Young University
Provo, UT 84602 USA
e-mail: richard_kellems@byu.edu

 Abstract

Quinoa is a cereal grain that originated in the highlands of South America. It is high in protein (12.2% Crude Protein (CP)), and in the limiting amino acids lysine and methionine. It also contains a number of anti-nutritional substances, such as saponins, phytic acid, tannins and trypsin inhibitors, which can have a negative effect on performance and survival of monogastric animals when it is used as the primary dietary energy source. Four trials were conducted to determine what effect different methods of processing quinoa (raw, washed, polished) and dietary CP levels would have on the performance and survival of broiler chicks fed quinoa as compared to wheat, maize and sorghum based diets. Raw quinoa fed broilers had reduced growth and dramatically reduced survival rates as compared to the washed or polished treatments. Broilers fed washed quinoa performed better than those fed polished quinoa.  Chicks receiving the washed quinoa performed nearly as well as those receiving the maize/soybean meal diets. The washing seemed to be  more effective than removing the outer hull (polishing) in removing the anti-quality factors that were depressing performance. Elevating the dietary protein level from (13.2 to 18 to 23 %) was shown to improve growth and survival in the quinoa-fed groups. The results of these trials indicated that washing and polishing the quinoa seeds prior to feeding and increasing the dietary CP or slightly reducing the amount of quinoa present in the diet, by adding soybean meal, improved growth and survival of broiler chicks.

Key words: Quinoa, broilers, survival, growth, anti-nutritional factors, saponins

Introduction 

Chenopodium quinoa Willd. (quinoa) is a grain chenopod that originated in the highlands of South America.   It was second only to potatoes in importance as a food crop for the Inca Empire (Cusack 1984).   It is a unique cereal grain, because it is resistant to drought and to light frost and can be grown in high mountain valleys of the Andes as well as other places, where the elevation is high and the growing season is short.   The plant requires 150 to 220 days to mature. It ranges in height from 0.7 to 3.0 m and seeds are small and round (2 to 3 mm in diameter) (Cusack 1984).  Quinoa has the highest CP content (12-19 %) of any of the cereal grains, and has an excellent amino acid profile, being high in both lysine (6.7 % of CP) and methionine (2.9 % of CP) (Gross et al 1989; Ahamed et al 1998; Galway et al 1990).  Tyrosine or phenylalanine were found to be the first limiting amino acids in quinoa (Ruales and Nair 1992).   Quality of the protein fraction was found to be comparable to casein (Protein Efficiency Ratio (PER), Digestible Crude Protein (DCP), N Balance)) (Ranhotra et al 1993).   Digestible CP (DCP) was found to be 78 % in raw quinoa and 83 % in washed quinoa and when the outer hull was removed the DCP was increased by 7 percentage points (Ruales and Nair 1994). 

Quinoa has the potential to become an important crop in high mountainous regions of the world  (Gross et al 1989; Vietmeyer 1986; De Bruin 1964).    Many of the world’s indigenous populations live in such areas and would benefit from such a crop and knowing how it must be processed prior to feeding it to livestock in order to maximize their performance. 

Several anti-nutritional substances have been found in quinoa, such as, saponins, phytic acid, trypsin inhibitors and tannins (Gonzalez et al 1989; Chauhan et al 1992).   Saponins were found to be the primary anti-quality factors associated with quinoa, but phytic acid and tannins were also found to be present (Coulter and Lorenz 1990; Ruales and Nair 1993) and it was only found to contain a small amounts of trypsin inhibitor (Ando et al 1999).  Oleanolic acid saponins were the main class of saponins found to be present in quinoa (Cuadrado et al 1995; Ma et al 1989).  

Feeding value of quinoa is low when it is fed raw, but when it was rinsed with water prior to feeding performance was improved (Chauhan et al 1999).  Washing has been shown to be an effective way to remove saponins, which would suggest that saponins or some other water-soluble anti-quality factors are responsible for the depressed growth that is observed when raw quinoa is fed. Saponins seem to be concentrated in the hull of the quinoa seed. The abrasive dehulling of quinoa was found to reduce the saponin content by 85.2 to 98.8 % (Reichert et al 1986).  The higher the initial saponin content the more bran had to be removed to reduce the saponin level (Reichert et al 1986).  Unwashed quinoa was found to decrease feed intake and feed conversion in rats (Ruales and Nair 1992).   Differences in levels of anti-nutritional factors may be found in different types of quinoa that have been grown under different conditions.  

Only a few reports are available relating to the feeding characteristics of quinoa and the responses have been inconsistant.   Dehulling of quinoa was only found to slightly improve performance in broilers (Jacobsen et al 1997).  In an earlier feeding study, using nine-week old chickens fed either washed or cooked quinoa for 30 day,  no differences were observed in weight gains between treatment groups (Gandarilla 1948).   Mahoney et al (1975) reported similar growth responses in rats fed washed quinoa, when compared to rats fed a casein-based diet. 

The following research trials were designed to evaluate the feeding characteristics of quinoa that had been subjected to mechanical removal of the exterior surface (polishing) or subjected to water extraction and compared it to raw quinoa or other commonly used cereal grains (wheat, sorghum, maize) in four survival and growth trials using broiler chicks. 

Processing of Quinoa 

The quinoa used in the following four trials was Chenopodium quinoa D-407.  Since many of the anti-nutritional factors associated with quinoa seem to be either water soluble or concentrated in the exterior surface of the seed, two methods (polishing or washing) of reducing the anti-nutritional factors were evaluated in this trial.   The first method was to polish the quinoa seed to remove the outer coating and this was done with a modified rice polisher, which resulted in a 10 to 15 % loss.  The second method was to wash the quinoa by soaking 2 kg of polished quinoa seeds in a bucket containing 14 litres of water for 30 minutes, during which time the mixture was continually stirred and the water was changed four times.   After washing, the seeds were dried at 65 degree C.   The quinoa prepared using both methods was then ground (1 mm screen) and blended with other feedstuffs to prepare the various diets.   Diets in all trials were formulated to be iso-nitrogenous and soybean meal was used to adjust the dietary CP levels.   All diets were fortified with a mineral and vitamin premix, so that they would meet National Research Council Poultry (NRC 1994) minimum requirements for minerals and vitamins (Tables 1 to 4). 

Materials and Methods 

The four trials were conducted to evaluate the effect that processing and dietary protein level would have on survival and growth of broiler chick being fed quinoa. Three replicates of ten 3day-old male broiler chicks were used to evaluate each of the treatments in each of the trials. All trials were conducted in environmental-controlled (30 degree C.) facilities. Feed and water were provided ad libitum during all trials. Birds were weighed weekly in all trials. Total feed consumption was determined on a pen basis for each trial. 

In Trial 1, one hundred fifty and chicks were used to compare the survival and growth rates of birds fed diets for 28 d containing raw quinoa (RQ), polished quinoa (PQ), wheat (W), sorghum (S) or maize (C) based diets formulated to contain 13.2 % CP (Table 1).   In Trial 2, one hundred and fifty chicks were used to compare the survival and growth of birds fed for 28 d the same treatments (RQ, PQ, W, S, C) used in trial 1, that were formulated to contain 18 % CP (Table 2).   In Trial 3, one hundred and twenty chicks were used to compare the survival and growth of birds fed for 14 d diets containing RQ, PQ, washed quinoa (WQ) or C diets, formulated to contain 13.3 % CP.  In Trial 4, one hundred and twenty chicks were used to compare the survival and growth of birds fed for 31 d the same treatments used in trial 2 (RQ, PQ, WQ, C) formulated to contain 23 % CP (Table 4). 

Analysis of variance was performed using the SAS (1991) software.   A log transformation was performed on the weights to correct for the variance inequalities of the residual plots in order to maintain the assumption of the analysis of variance: equal variances of residual plots. The new dependent variable is “ln y", where "y" is the weight of the bird. The PROC MIXED in SAS was used and the model is as follows: Ln y = u + Tt + Pp + TPtp + C(p)c + e 

Where:           u = overall mean            Tt = treatment effect
                    Pp = protein effect           TPtp = interaction           
                    C = random cage effect    e = experimental error 

Survival and growth data were analyzed using the PROC GLM Procedure in SAS (1991). The dependent variable was the arc sin of the percentage of birds that were still alive at any particular week that was analyzed. The model was as follows: arc sin y = u + Tt + Pp + TPtp + e 

Where:            u  = overall mean            Tt = treatment effect
                     Pp = Protein effect          TPtp = interaction
                       e  = experimental error

The feed consumption data was analyzed using the following model: y = u + t + e

Where:            u = overall mean                t = treatment effect            
                        e = experimental error

Results and Discussion 

Trial 1. Growth and survival of broiler chicks fed low dietary CP (13.2 %) diets containing raw quinoa, polished quinoa, wheat, sorghum or maize. 

Up to 3 weeks, broilers fed the RQ diet had a lower (P<.05) survival percentage than all other treatments (Table 5). After four weeks the broilers fed PQ had a survival percentage that was lower (P<.05) than the cereal grain treatments, but higher than the RQ treatment.

Growth rates (Table 5) for birds receiving the PQ and C groups were similar, but those receiving the PQ gained less (P<.05) than the W and S groups. The S treatment had the highest consumption, which may have accounted for the increase in growth observed in that treatment as compared to the others. 

The high mortality and depressed growth for the quinoa groups could be caused by a number of factors, such as a toxicity, reduced feed consumption, mineral deficiency, inadequate dietary protein, or an amino acid deficiency.  Presence of saponins has been shown to depress feed consumption in some species (Cheeke et al 1983), which would effect both growth and survival. West et al (1978) found evidence of binding between ammoniated glycyrrhizin, alfalfa saponins and zinc, which may cause a zinc deficiency to occur, which can lead to anorexia and reduced growth (Mills et al 1969).  These results suggest that the amino acid profile of the quinoa was not superior to any of the cereal grains evaluated (W, S, C) when combined with soybean meal, or that there was enough of the anti-quality substance remaining in the PQ to interfere with its protein utilization.  Feed consumption data would also suggest that anti-quality substances were still present in adequate amounts to depress feed intake in the PQ.  The depression in growth and feed consumption by the birds fed the W diet was unexpected. 

Trial 2.     Growth and survival of broiler chicks fed adequate dietary CP (18 %) diets containing raw quinoa, polished quinoa, wheat, sorghum or maize. 

In this trial the same treatments were used as in trial 1, but the dietary CP level was raised to 18 %. The survival percentages (Table 6) in both the RQ and PQ groups were higher (P<.05) when the 18 % CP (trial 2) level was compared to the 13.2 % CP (trial 1).   Survival percentages in the W, S, C treatments were not found to be different (P>.05).   The statistical analysis showed that dietary CP did not (P>.05) affect survival of the broilers receiving the W, S or C treatments.   Thus, it could be inferred that increasing the dietary CP levels, or reducing the amount of quinoa in the RQ and PQ diets, partly counteracted the anti-nutritional effect associated with quinoa that was causing the elevated mortality rate. 

 The weight gains (Table 6) on all treatments were higher (P<.05) for the broilers being fed the diets containing the 18 % CP (Trial 2) when compared to the 13.2 % CP (Trial 1). The gain was higher (P<.05) for the PQ when compared to the RQ treatment when the dietary CP was at 18%.  The W and S treatments had higher gains (P<.05) than the C when the dietary CP was at 18 %, but the S treatment tended to have the highest weight gains of any of the cereal grains. These differences may be the result of the saponins found associated with quinoa and which depressed feed consumption and would agree with the results of Peterson (1950) and Cheeke (1971). 

Trial 3.  Growth and survival of broiler chicks fed low dietary CP (13.3 %) diets containing raw quinoa, polished quinoa, washed quinoa or maize. 

After 14 days on the 13.3 % CP level, that survival rate was lower (P<.05) for the RQ vs the PQ or WQ treatments and this trend continued for the remainder of the trial (Table 7). The PQ had a lower (P<. 05) survival percentage than the WQ, starting from 7 days and this continued for the remainder of the trial. There was no difference (P>.05) in survival between the WQ and the C treatment. This would indicate that enough of the anti-nutritional factors had been removed when the PQ was washed and dried prior to being fed. 

Weight gains were not calculated for the RQ treatment, because of the low survival percentage. Weight gains were lower (P<.05) for the PQ as compared to the WQ or C treatment (Table 7). There was no difference (P>.05) between the WQ and C treatments with respect to weight gains.   Again, this would suggest that washing the PQ reduced further the amount of the anti-nutritional factors that were present in the quinoa and weight gains were similar to the maize based diet. The WQ was comparable in gain and feed conversion to the C treatment. 

Trial 4. Growth and survival of broiler chicks fed high dietary CP (23%) diets containing raw quinoa, polished quinoa, washed quinoa or maize. 

When the dietary CP level was raised to 23 % using soybean meal, this reduced the amount of quinoa in the diet (Table 4) and the survival percentage for the RQ treatment increased, but was still lower (P<.05) at 28 days than on the other treatments (Table 8).   The survival percentage at 28 days was not different (P>.05).   Increasing the dietary CP level, or reducing the amount of quinoa, increased the survival percentage, especially for the RQ treatment.    Weight gains (Table 8) were different (P<.05) between treatments starting on 14 days and continued until the end of the trial.   Birds receiving the PQ performed better (P<.05) than those receiving the RQ and those receiving the WQ performed better (P<.05) than those receiving the PQ.   The 23 % CP maize treatment had a higher weight gain (P<.05) than the WQ treatment.   Total feed consumption (kg) was: 18.2, 35.6, 45.1 and 47.6, respectively, for RQ, PQ, WQ and C treatments.  Feed consumption of the RQ was lower (P<.05) than the consumption in all other treatments.   The broilers on the PQ consumed less feed (P<.05) than the broilers fed WQ or the C diets.   Feed conversions were: 7.0, 3.3, 2.3 and 1. 8, respectively, for the RQ, PQ, WQ and C treatments.   These results suggest that increasing the dietary CP level, or slightly reducing the amount of quinoa in the diet, and both types of processing had positive effects on survival and performance of broilers receiving quinoa. 

Conclusions 

The results of these trials demonstrated that processing (polishing or washing) quinoa prior to feeding it can reduce the negative impact of the anti-nutritional factors associated with quinoa.   Washing the polished quinoa improved performance more than polishing alone.   Increasing the dietary CP level also seemed to reduce the depressing effect associated with raw quinoa and increased both survival and growth rates.   These results indicate that both processing of quinoa prior to feeding, or diluting the quinoa with some other available feed, or supplementing with additional CP can be viable options that can be considered for improving performance of broilers when quinoa is a major component of the diet. 

References 

Ahamed N T, Singhal R S, Kulkarni P R, Mohinder-Pal and Pal M 1998  A lesser known grain, Chenopodium quinoa; review of the chemical composition of its edible parts.  Food and Nutrition Bulletin, 19 (1) 61-70. 

Ando H, Tang-Hanjun, Watanabe K, Mitsunaga T and Tang H J  1999  Characteristics of quinoa as a foodstuff. Part 1. Characteristics of the food component in quinoa in comparison with other cereals.  Bulletin of the Institute for Comprehensive Agricultural Sciences, Kinki University, No. 7 pp 107-111. 

Chauhan G S, Eskin N A M, and Tkachuk R 1992  Nutrients and anti-nutrients in quinoa seed. Cereal Chemistry 69 (l) 85-88.  

Chauhan  G S, Eskin N A M and Mills P A  1999  Effect of saponin extraction on the nutritional quality of quinoa (Chenopodium quinoa Willd.) proteins.  Journal of Food Science and Technology, 36 (2) 123-126. 

Cheeke P R 1971  Nutritional and physiological implication of saponins: A Review. Canadian Journal of Animal. Science 51:621-632. 

Cheeke  P R, Powley J S, Nakue H S and Arscott G H 1983  Feed preference, responses of several avian Species fed alfalfa meal high and low in saponin and quinine sulfate. Canadian Journal Animal Science 63 (3) 707-710.  

Coulter L and Lorenz K 1990  Quinoa – composition, nutritional value, food applications. Lebensmittel Wissenschaft und Technologie, 23 (3) 203-207. 

Cuadrado C, Ayet G, Burbano C, Muzquiz M, Camacho L, Carieres E, Lovon M, Osagie A and Price K R 1995  Occurrence of saponins and sapogenols in Andean crops. Journal of the Science of Food and Agriculture. 67 (2) 169-172. 

Cusack D  F 1984  Quinoa: grain of the Incas. The Ecologist 14:21-30.  

De Bruin A 1964  Investigation of the food value of quinoa and canihua seed. Journal Food Science 29:872-876.  

Galway N W, Leakey C L A, Price K R and Fenwick G R  1990  Chemical composition and nutritional characteristics of quinoa (Chenopodium quinoa Willd.), Food Science and Nutrition, 4:245-261. 

Gandarilla H 1948  Efecto fisiologico de la saponina de la quinoa en los animales. Review. Agriculture:52-56.  

Gonzalez J A, Roldan A, Gallardo M, Escudero T and Prado F E 1989  Quantitative determinations of chemical compounds with nutritional value from Inca crops: Chenopodium quinoa. Plant Foods for Human Nutrition. 39 (4) 331-337.  

Gross R, Koch F, Malaga L, de Miranda A F, Schoeneberger H  and Turgo L C 1989  Chemical composition and protein quality of some local Andean food sources. Food Chemistry. 34:25-34. 

Jacobsen E E, Skadhauge B and Jabobsen S E 1997  Effect of dietary inclusion of quinoa on broiler growth performance. Animal Feed Science and Technology, 65:1-14. 

Ma W W, Heinstein P F and McLaughlin J L 1989  Additional toxic, bitter saponins from the seeds of Chenopodium quinoa. Journal of Natural Products. 52 (5) 1132-1135. 

Mahoney A W, Lopez J G and Hendricks D G 1975  An evaluation of the protein quality of quinoa. J. of Agric. Food Chemistry. 23 (2) 190-193. 

Mills C R, Quarterman L, Chesters J C, Williams R B and Dalgano A C 1969  Metabolic role of zinc. American. Journal of Clinical Nutrition 22:1240-1249. 

NRC 1994  Nutrient Requirements of Poultry, National Research Council, National Academy Press, Washington, D.C. 

Peterson D W 1950  Some properties of a factor in alfalfa meal causing depression of growth in chicks. Journal of Biological Chemistry. 183:647-653. 

Ranhotra G S, Gelroth J A, Glaser B K, Lorenz K J  and Johnson D L 1993  Composition and protein nutritional quality of quinoa.  Cereal Chemistry. 70 (3) 303-305. 

Reichert R D, Tatarynovichm J T and Tyler R T 1986  Abrasive dehulling of quinoa (Chenopodium quinoa): effect on saponin content as determined by an adapted hemolytic assay.  Cereal Chemistry 63 (6) 471-475. 

Ruales J and Nair B M 1992  Nutritional quality of the protein in quinoa (Chenopodium quinoa, Willd) seeds.  Plant Foods for Human Nutrition, 42 (1) 1-11. 

Ruales J and Nair B M 1993  Saponins, phytic acid, tannins and protease inhibitors in quinoa (Chenopodium quinoa, Willd) seeds.  Food Chemistry 48 (2) 137-143. 

Ruales J and Nair B M 1994  Effect of processing on in vitro digestibility of protein and starch in quinoa seeds.  International Journal of Food Science and Technology, 29 (4) 449-456. 

SAS 1991  SAS User's Guide: Statistics 1991 ed., SAS Institute Inc., Cary, NC. 

Vietmeyer N 1986  Lesser-known plants of potential use in agriculture and forestry. Science 232:1379-1384.  

West L G, Greger J L, White A A, Nornamaker B  1978  In vitro studies on saponin­ mineral complexation. Journal of  Food Science. 43:1342-1343.

Received 29 November 2000

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