Sunflower seeds have been common components of psittacine diets for many years. Recently however, their use has been questioned because they are reputed to cause behavioral problems. It has been suggested in advertisements and by some aviculturists that they contain harmful substances which are responsible for poor breeding, feather problems and aggressive behaviors such as biting. As was pointed out in Exotic Bird Report, No. 1 (1983), there have been no published studies to document these assertions.
The opinion that sunflower seeds are harmful is based on the claim that they contain a substance called papaverine, which is claimed to be a deleterious narcotic. No substantiation for this claim has been published, yet the myth is perpetuated. Where does the truth lie?
Papaverine, produced by the opium poppy, is an alkaloid which was discovered in 1848 by G. Merck in Germany. It is not a narcotic by either a legal or pharmacologic definition but rather is classified as a smooth muscle relaxant that is used in internal medicine. No plant except: the opium poppy has been shown to produce papaverine.
Although there is no logical reason to suspect the presence of papaverine in sunflower seeds, aviculturists have been concerned about this possibility, hence attempts were made to determine whether or not it is true. This was difficult initially because high levels of fat in sunflower seeds mask the papaverine during conventional analysis. By use of different techniques, however, the evidence is strong that the seeds contain no papaverine. The best method for finding out whether small amounts of a substance can be detected is to submit to the laboratory a series of samples with known amounts of the substance added to some of the samples. If the analytic technique is adequate to detect -small amounts of papaverine, for example, the laboratory report should show that samples to which papaverine has been added (spiked) contain more papaverine than samples to which none was added.
I undertook just such a test with the cooperation of a commercial laboratory*. A sample was prepared from California Grey Stripe sunflower seeds, obtained from a local retail store, by grinding the entire sample and dividing it into three lots. One was spiked with 100 ppm (100 mg per kg) papaverine, a second with 10 ppm papaverine and a third left unspiked. The samples were labeled by a code so that analysts at Curis & Tompkins did not know their identities, and analyses were carried out by chromatographic and mass spectrographic methods. The results are presented in the table. The detection limit of the methods used was 1.0 ppm; 0.1 ppm would have shown as a trace.
Papaverine in Sunflower Seeds
100 ppm 60 ppm
10 ppm 8 ppm
0 ppm no trace
*Curtis & Tompkins, Ltd. Analytical Laboratories, 290 Division Street, San Francisco, CA 94105
The results of the analyses show clearly that no more than 0.1 ppm of papaverine could be present in the seeds. For a parrot that weighs l00g and eats 4.8g sunflower meats per day, less than 0.1 ppm of papaverine would translate to less than 0.0048 mg per kg body weight per day. (calculations: 0.1 ppm - 0.1 mg per kg food; therefore 4.8 g food contains less than 0.00048 mg. The parrot weighs 100 g — 0.1 kg; therefore 0.00048 mg + 0.1 kg = 0.0048 mg per kg body wt. per day). As judged by the effective dose used in human patients (8.5 mg per kg body wt per day), the amount that would be ingested by an l00g parrot if it ate only sunflower seeds (less than 0.0048 mg per kg body wt per day) is exceedingly small.
The results obtained are those one would expect from such an analysis. The sample containing 100 ppm was measured at only 60 ppm because at this high concentration the precision of the technique becomes reduced. At 10 ppm the accuracy is better, again as one would expect, because it is in that part of the range where there is a linear response of the equipment to changes in concentration of papaverine. The technique is a useful method for looking for papaverine. When no papaverine was added, none was found.
The results obtained should clear up any controversy about the presence of papaverine in sunflower seeds, because this sensitive analysis of sunflower seeds has failed to detect the alkaloid. The technique was tested with spiked samples in a blind test and shown to be accurate. Until reliable evidence to the contrary appears, we are left with only one conclusion: Sunflower seeds do not contain papaverine.
Avicultural science and management must, like all sciences, hold evidence to the light for rigorous testing. Claims for benefits or adverse effects must be tested by experiment, not by opinion or testimonial. It is the obligation of the person making a claim to present the evidence on which the conclusion is based, quantitative and detailed evidence that can be verified independently. Conclusions drawn after being subjected to this scrutiny become stronger, more reliable, and most useful for application in the real world of aviculture.