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(3) The effect of substituting a basal diet of growing pigs with fresh forages on apparent digestibility and nitrogen retention

(3) The effect of substituting a basal diet of growing pigs with fresh forages on apparent digestibility and nitrogen retention
 

Nguyen Nhat Xuan Dung1, Luu Huu Manh1, Truong van Phuoc1, Peter Uden2
and Brian Ogle2

1Cantho University, Cantho, Vietnam.
nnxdung@ctu.edu.vn
2 Swedish University of Agricultural Sciences

Abstract

The effect of substituting a basal diet with duckweed (Lemna minor), para grass (Brachiaria mutica) and water spinach (Ipomoea aquatica) on the apparent digestibility and nitrogen retained was determined. Eight Baxuyen crossed castrated male growing pigs (Ba Xuyen X Yorkshire). were used in two experiments to evaluate the total tract apparent digestibility of dry matter (DMD), crude protein (CPD), neutral detergent fiber (NDFD), acid detergent fiber (ADFD) and nitrogen retained (NR). In the first experiment, 4 pigs were offered a basal diet at 4% of body weight and fresh forages were fed ad libitum. Fresh forages were offered after the pigs had consumed the basal diet. There were no significant differences in DMD, CPD, NDFD, ADFD and NR among the 4 diets (P>0.05). In the second study, 4 pigs were offered a basal diet at a level of 3% of body weight after consuming the fresh forages. The dry matter intakes of the fresh duckweed, water spinach and para grass were 11, 7 and 19% of total dry matter intake, respectively. Feed intakes of the treatments that included the fresh forages were reduced in comparison with the control, and there was a similar tendency in the digestibility of dry matter, crude protein, NDF, EE, ADF and N retained among diets (P>0.05), probably as a result of the high CP content of the substituted feeds. It is concluded that offering fresh forages ad libitum improved nitrogen retention and reduced total dry matter intake but did not decrease nutrient digestibility. Among fresh forages, water spinach is more palatable than duckweed and Para grass.

Key words: duckweed, digestibility, intake, nitrogen retained, para grass, pig, water spinach