Black Tongue In A Newborn Kitten

[Alkiparis]

Hi everyone!
My cat gave a birth to 4 alive kittens just 2 days ago. Additionally, two kittens were born dead. Today I noticed that at least two of 4 kittens have entirely black tongue tips, not like spots. These two kittens are somehow weaker than others, they breast feed less actively. 3 kittens gained about 10 grams since yesterday, the smallest one - only 3-4 grams.
The vet did not provide any adequate clues.
Did anybody have the same experience? Is it something serious, and if it is, what can I do to save my kittens?

 

[talkingpeanut]

Can you post a photo?

 

[Alkiparis]

It's been a long time since I posted this - so I decided to come back and answer my own question.
All four kittens are big and noisy naughties now. It turned out I'd missed the most important thing in my question: the cats are sphynxes. And the black thing on their tongues - it was their mom's skin sebum, that they were licking while trying to find a nipple.
So nothing serious in our case =)

 

[golondrina]

A belated but hearty welcome to you Alkiparis and your 4 kittens.
I am sorry you didn't get a reply to your query but happy your kittens are doing so well. I never saw your tricky question but even if I had I wouldn't have been able to help.
I would love to see some photos of your kittens and know their names.