Pandas mainly feed on broad-leaved mixed forests under the alpine, subalpine and middle-low mountain, mixed with coniferous, and bamboo plants growing under the forest with a canopy density of 50-70% of the small diameter.
According to a survey, Sichuan Province alone has 19 kinds of bamboos, counting for nearly 164 species, among which 23 of them belong to arrow bamboo. There more than 40 species of bamboos available for pandas, there’re also approximately 30 kinds of bamboo for their principal food.
Bamboos in Sichuan are largely distributed. There is a rich variety of species, they’re in a nutritional growth period, and they produce many bamboo shoots. The annual and second-year bamboos account for a large proportion of the population and are the best food base of pandas.
Bamboo is a gramineous plant. Since it has woody stems, it is high in fiber. Bamboo tissue consists of two parts: cell content and cell wall. The contents of the cell are mainly protein, amino acid, sugar, fat, and a large amount of water.
These are substances that are easily digested by animals, and the content of protein and amino acid are relatively higher. The cell wall is composed of tough cellulose, hemicellulose, and lignin. Herbivores can decompose and utilize cellulose and hemicellulose through ruminants, cecum, fermentation and microbial action.
Carnivores and omnivores do not have the ability to digest and utilize cell walls. Pandas treat bamboos as their principal source of food, although they still utilize hemicellulose, it is still relatively rare.
The nutrients of bamboo include crude protein, crude fat, coarse ash, nitrogen-free extract, and crude fiber. The nutrient content varies with different parts of the bamboo plant.
The commonly seen types are crude fat, crude protein, and nitrogen-free extract. The content gradually increased from the upper part to the lower part of the bamboo plant, and the leaves contain the highest amount of nutrients.
On the contrary, it’s a different story with crude fiber. Its content gradually decreases from the lower part to the upper part of the bamboo plant.
Meanwhile, for bamboos of different ages, they also consist of various amounts of nutrients. Among all the nutrients, the differences among water, protein, and sugar are more evident. The water and protein content decrease with the aging of the bamboo.
Usually, they decrease along with bamboos that are annual, bi-annual, and perennial. For sugar, its content increases along with the aging of bamboo. In different kinds of bamboos, we also find various amounts of nutrients.