Effect of dietary fiber sources on feed intake, nutrient digestibility, growth rate, and economic return of growing rabbits fed sweet potato vine (Ipomoea batatas) and para grass (Brachiaria mutica)
 

Nguyen Thi Kim Dong, Nguyen Van Thu, Brian Ogle* and T R Preston**

Cantho University, Cantho City, Vietnam
ntkdong@ctu.edu.vn
* Department of Animal Nutrition and Management,
Swedish University of Agricultural Sciences, Uppsala, Sweden
** UTA, TOSOLY, AA#48, Socorro, Santander, Columbia 

A study was conducted in the experimental farm of Cantho University to evaluate the effects of dietary fiber sources from sweet potato vine and para grass (PG) as potential feed for rabbits. Two experiments were of 2*3 factorial designs with two factors and three replications and two male rabbits in each experimental unit. The first factor was diet (sweet potato vine and sweet potato vine plus para grass with ratio of 1:1), the second one was the level of DM feed offered (8, 9 and 10% of LW). The first trial was done on growing rabbits at 8 weeks of age to evaluate feed intake, growth performance and economic returns, while in the second experiment feed digestibility, nitrogen retention and caecum fermentation of rabbits was determined at twelve weeks of age.

 In Expt. 1, the dry matter (DM) and organic matter (OM) intakes were significantly higher (P<0.001) on the diet that included sweet potato vine (SPV) plus para grass (PG), while the intakes were quite similar among the three levels of feed offered. Crude protein (CP) intake was not significantly different between the two feeds and three levels of feed offered. NDF and ADF intakes were not different among levels of feed, but the values were significantly lower (P<0.001) in the diet with only SPV. The daily gain was not significantly different for both the two factors, however, the lower FCR was found  (P<0.001) in the diet without PG. Lower feed cost resulting in higher benefit was found for the diet including SPV plus PG and the level of DM feed offered at 8% of live weight.

In Expt. 2 the apparent digestibility (%) of DM, OM, CP, NDF and ADF were significantly higher (P<0.001) in the diet fed only SPV. The significantly lower nitrogen retention (P<0.001) was found in the diet included SPV plus PG. The total volatile fatty acids (VFAs) were significantly higher (P<0.01) for rabbits fed only SPV. There was no significant difference in the result of gas production between the two diets and the three levels of feed offered.

It was concluded that there are no nutritional benefits from supplementing sweet potato vine with para grass for growing rabbits.

Key words: digestibility, growing rabbits, para grass, sweet potato, volatile fatty acid, weight gain