Human sperm does contain lots of polyunsaturated fats, of the kind of omega 3 fats. In contrast to this, avian sperm does contain mainly fats of the omega 6 series. As these fats cannot be synthesized in the body they have to be supplied in their food. As fertility has decreased over the last 30 years every external factor which could contribute to this needs our attention.
Birds differ with many species as they demonstrate internal fertilization and the testis are inside the body, with a temperature of 41-43°C. Another aspect is sperm stays up to 2 weeks in the uterovaginal glands of the hen, from which sperm is released daily to the upper oviduct and fertilization site. Avian sperm, just as human sperm does contain many lipids, mainly in the cell wall, and is made up for up to 80% of phospholipids and 20% free cholesterol. Of these phospholipids most are polyunsaturated fats. If we look at the omega 3 to omega 6 ratio, human sperm has a high ratio in contrast to birds having a very low ratio. This cannot be explained by diet differences between humans and birds, so these are species specific.
Detailed scientific information about all kind of fats can be found on the internet, but in this article I want to explain why some oils are better as to others and why. The main omega 6 fats in avian sperm are linoleic acid, arachidonic acid and DTA (22:4 n6).
It has been proven that dietary changes in the food regimen of birds can improve lipid composition of avian sperm. But together with this the susceptibility of oxidation of these fats increase, by which antioxidant status has to be altered too. It is at this point where vitamin E comes along, together with selenium in the prevention of oxidation of sperm lipids. Vitamin E levels have to be around 200mg per kilo of food for this. Thus, vitamin E, known as the fertility vitamin, performs its action as to fertility.
The importance of these omega 6 fats can be explained on four levels.
One is they make up the most important structural component of the sperm itself, mainly in the membrane, as a structural component, but also very important for sperm motility. Inadequate provision leads to impaired differentiation and in worse cases the inability to produce sperm. The older the cock bird the more important!
Two, they prevent sperm from dying too fast, these fats protect the sperm from degradation as they reside in the uterovaginal glands for up to 2 weeks.
Third, supplementation of these fats stimulates spermatogenesis.
Four, they are very important in the hormonal control of spermatogenesis. Brain lipids are mainly polyunsaturated fats, especially DTA, and as we all know longer daylight hours stimulate the birds for breeding, in which the hypothalamus, the pituitary gland and gonads all work together through different hormones like GnRF, LH, FSH and androgens to get spermatogenesis going. Also melatonin comes along, because it inhibits the release of hormones in the hypothalamus.
Important note here is birds get sexually stimulated not only by lengthening daylight hours, but even more by longer wavelengths penetrating the skull and reaching the hypothalamus, this is important as these waves belong to the infrared spectrum of light, and most, if not all, fluorescent light tubes do not emit light in this part of the light spectrum. These receptors, apart from the eye, do need exceptional high levels of DHA, the only omega 3 fat needed in spermatogenesis.
Let’s get to the practical implications of these facts.
If we want to provide our birds pre breeding with some oils, the use of plant oils is not my choice as their seeds already contain these oils.
By the way, brewery by products also exert their action because of their linoleic acid and not because of their vitamin B contents, as often thought. And if you use bakery yeast you get a free probiotic which is in bakery yeast products, as big birdfood companies use the dead end product of making beer.
But we also need arachidonic acid, which cannot be found in plant oils, but are found in animal sources like eggs, and even more in abundance in larvae, like pinkies.
This, and not only protein content , might be an additional explanation for the success of feeding pinkies pre breeding. I have never understood as many say the need for animal protein as, as long as the amino acid score is right, protein is protein, and eggs do match this. On a dry weight base eggs and pinkies have the same protein content, around 50%, pinkies even having a lower amino acid score, so there has to be another explanation for their fertility promoting action, in which their fat content in linoleic acid and arachidonic acid could be one of the possible explanations.
The fatty acid DTA (22:4 n-6) cannot be given in the food, but is synthesized from DHA, the only omega 3 fat in this context, can be provided through a little bit of fish oil, but as this can cause intestinal problems, oils made from sea microalgae are now produced safe for human use, used by vegetarians and approved by the EU. These oils are better tolerated and are safe to use.
Dr. Jan Vanderborght firstname.lastname@example.org