Motor incoordination, intracranial fat bodies, and breeding strategy in Crested ducks (Anas platyrhynchos f.d.).

Some Crested ducks (CR) are burdened with an intracranial fat body that, depending on the size and location, may lead to varying degrees of motor incoordination. A behavioral test is proposed that helps to identify those CR individuals bearing the problematical fat body. The test consists of putting the ducks on their backs and measuring the time required to right themselves. This was repeated 13 times per animal, and means were calculated. The minimum time required was 0.5 s, and the maximum was 62.6 s. Individuals that show motor incoordination need more time than ducks without such problems (14.3 s in contrast to 1.2 s) and exhibit a larger intracranial fat body. Ducks used for breeding should require no more than approximately 1 to 2 s to right themselves. In an allometric comparison with 3 other domestic duck breeds, CR show a significantly smaller brain; specifically, the cerebellum, tegmentum, apicale hyperpallium, and olfactory bulb are reduced. The relationship between fat body and these structures was discussed.

[Intracranial fat bodies and their potential effect on brain composition and behaviour in domestic ducks with feather crests (3 case studies)]. / Intrakraniale fettkörper und ihre potentiellen Auswirkungen auf Hirnbau und Verhalten bei hauben- tragenden Hausenten (3 Fallstudien).

Intracranial fat tissue was found in the brains of three crested ducks. The three ducks differed in the size of their crest and in the volume and the location of the fat body within their brains. The duck with the large crest showed a fat body which counts for 19 % of its brain volume. Due to this fat accumulation, brain structures, mainly the cerebellum, were moved laterally. This duck had serious problems in motor coordination. Fat body of the second duck with a middle sized crest was situated in neostriatum and constituted 0,6 % of total brain volume. Additionally this duck displayed an encephalocele. The last duck did show a small crest. Its fat body was found in the area of the tentorium cerebelli and made up 17 % of its brain volume. The later two ducks were not hampered behaviourally.

The role of insulin-related substance in Hodgkin's disease.

An insulin-related growth-promoting substance was detected in the serum of a patient with Hodgkin's disease who suffered from severe hypoglycaemia, as well as in the supernatant of homogenized spleen tissue of the same patient. Low concentrations of this substance enhanced DNA synthesis of short-term-cultured spleen tumour cells obtained from the same patient, while the addition of anti-insulin antiserum interfered with that effect. Moreover, the preincubation of this insulin-related substance with the anti-insulin antiserum abrogated its stimulatory effect on tumour cell proliferation. Both insulin and the insulin-related substance bound to patients splenocytes to a similar extent. The data suggest that the insulin-related substance, found in this particular case of Hodgkin's disease, plays a role in tumour progression by an autocrine mechanism.

Brain alterations in crested versus non-crested breeds of domestic ducks (Anas platyrhynchos f.d.).

A comparison of brain size and brain composition was made between two uncrested duck breeds and Crested Ducks (CR) and between CR individuals that do possess crests and those that do not have the crest. Domestic ducks of the breed CR have allometrically larger brains than uncrested duck breeds. The crest inserts on a cushion of fat and connective tissue that is partly nourished by brain vessels via small holes in the skull. Through these holes, fat tissue may invade the brain cavity. Because the fat accumulations are sometimes hidden deep between the telencephalon, tectum, and cerebellum, they may be invisible macroscopically and, thus, give the impression of a large brain. The size of the crest, however, is not strictly correlated with fat accumulations in the brain, because 2 among 10 specimens of CR showed no fat body at all, and the investigation of 10 uncrested CR (ducks from the same genetic stock, but without the crests) also revealed fat accumulations in 6 specimens. After subtraction of the volume of the fat body, the brain volume of CR (crested and uncrested) was of equal size to that of "Hochbrutflugenten" and Pommeranian ducks, as was the volumes of most brain structures measured. Significantly smaller in CR were the olfactory bulbs, the prepiriform area, and the cerebellum, which was always situated in close proximity to the fat body in CR.