Elderberries are a genus of flowering plants that are from the honeysuckle family. They produce fruit of the same name which are used to produce elderflower cordial.
So can rabbits eat Elderberries at all?
Lets take a look at their nutritional data and find out more. In particular their acidic, calcium, sugar, phosphorus, fibre, fat and sodium content is of most interest as far as rabbits are concerned.
Energy 305 kJ (73 kcal)
Carbohydrates
18.4 g
Dietary fiber 7 g
Fat 0.5 g
Protein 0.66 g
Vitamins
Vitamin A equiv. (4%) 30 μg
Thiamine (B1) (6%) 0.07 mg
Riboflavin (B2) (5%) 0.06 mg
Niacin (B3) (3%) 0.5 mg
Pantothenic acid (B5)
(3%) 0.14 mg
Vitamin B6 (18%) 0.23 mg
Folate (B9) (2%) 6 μg
Vitamin C (43%) 36 mg
Trace metals
Calcium (4%) 38 mg
Iron (12%) 1.6 mg
Magnesium (1%) 5 mg
Phosphorus (6%) 39 mg
Potassium (6%) 280 mg
Zinc (1%) 0.11 mg
source https://en.wikipedia.org/wiki/Sambucus
As you can see Elderberries contain a little calcium, quite a lot of phosphorus, a hint of fat and fibre.
This means that rabbits can eat elderberries two to three times a week, just regulate how much they eat as they cant eat too much.
They can also eat elderberry leaves as they are fine for rabbits to eat.