Ileal and total tract digestibility in growing pigs fed cassava root meal and rice bran with inclusion of cassava leaves, sweet potato vine, duckweed and stylosanthes foliage

D T Hang, N Q Linh, H Everts^* and A C Beynen^*

Faculty of Animal Husbandry and Veterinary Medicine, Hue University of Agriculture and Forestry, Hue City, Vietnam,
^* Department of Nutrition, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands

Four F1 (Large White x Mong Cai), crossbred pigs, surgically fitted with post-valve T-caecum (PVTC) cannulas, were used in a 4*4 Latin square arrangement to determine the nutritive value of feeds in which the foliages from sweet potato, cassava, duckweed and stylosanthes provided 30% of the dry matter of the diet, the remainder of which was a mixture (50: 50) of cassava root meal and rice bran.

The diets with fresh water spinach or fresh cassava leaves had a higher apparent digestibility of organic matter in the total digestive tract but not at the level of the ileum, when compared with the diets containing sweet potato vines or stylosanthes foliage. Apparent digestibility of crude protein was also higher on the diets with water spinach and cassava leaves but the differences were confounded by different concentrations of crude protein in the foliages, and were not significant when the digestibility coefficients were corrected by covariance for differences in protein content of the diets.

The total tract apparent digestibility of the crude fiber ranged from 44 to 51%, and did not differ among diets. On all the diets, a substantial proportion of the crude fiber (close to 40%) was digested pre-caecally.

Key words: Pigs, Sweet potato vines, Duckweed, Cassava leaves, Stylosanthes foliage,  Digestibility, Ileal cannulas.