Mini-project Research protocol  

MSc in Tropical Livestock Systems (2005-2007)
Contents

Citation of this paper

Effect of different levels of fresh sweet potato leaves as partial replacement for cassava leaf silage for growing pigs fed a basal diet of rice bran and cassava root meal

Effect of different levels of fresh sweet potato leaves as partial replacement for cassava leaf silage for growing pigs fed a basal diet of rice bran and cassava root meal

Nakkitset Supharoek

Royal Project Foundation, Chiang Mai, Thailand
inalaw@yahoo.com

Introduction

Many farmers who are raising pigs use local feed resources such as cassava leaf, as a protein source to replace soybean meal and fish meal which are of high cost. Cassava leaves have a relatively high crude fiber and crude protein content; values ranging from 17 to 34% crude protein in dry matter have been reported for cassava leaf meal (Ravindran et al 1983). The protein in cassava leaves has been reported to be rich in lysine but limiting in methionine (Eggum 1970, cited by Chhay Ty et al 2005) and sometimes cassava quantity is not enough for feeding to pigs. Fresh sweet potato leaves become one choice of local feed resources as protein source for partial replacement of cassava leaf. Fuller and Chamberlain (1982) reported about nutritional quality and deficiencies of sweet potato roots and vines in total sulphur-containing amino acids and lysine in terms of an ideal protein for pigs.  Sweet potato leaves had a crude protein (CP) content of 25.5-29.8% in dry matter, which was markedly higher than in the stems, the mean ileal and total tract digestibility of the CP of sweet potato leaves was 74% and 76%, respectively reported by Le Van An (2004).

Hypothesis
Objective

To study the effect of different levels of fresh sweet potato leaves as partial replacement for cassava leaf silage for growing pigs fed a basal diet of rice bran and cassava root meal.
 

Materials and methods

Location

The experiment will be done in the Livestock Research center, Nam Xuang, Vientiane province, Laos and will last about 30 to 35 days

Animals

These will be 10 growing pigs with body weight about 10 - 20 kg.

The experimental design

The experiment design is a Completely Randomized Design and there are five treatments and two replicates with five levels of sweet potato leaves(SPL) replacing cassava leaf silage (CLS) in a basal diet of rice bran and cassava root meal in equal ratio. The treatments are:

Feeds and feeding system

The basal diet of rice bran and cassava root meal will be fed at 2% (DM) of body weight. The sweet potato leaves and cassava leaf silage will be chopped and mixed together, fed ad libitum about 120% of observed intake. Diets will be fed twice daily about 7.00am and 16.00pm. Water will be freely available all the time.

Measurements

The pigs will be weighed at the beginning and every 5 days. Feed offered and refused will be weighed daily and samples taken every 5 days to determine DM, N, and water soluble DM. DM is determined by micro-radiation (Undersander et al 1993) and N according to AOAC (1990). Water soluble DM is determined by the method of Ly and Preston 1997).

Statistical analysis

The regression models in Excel software will be used to relate level of replacement with sweet potato leaves (Independent variable) with performance data (dependent variables are growth rate, feed intake and feed conversion). 

References

Chhay Ty and Preston T R 2005: Effect of water spinach and fresh cassava leaves on intake, digestibility and N retention in growing pigs;  Workshop-seminar "Making better  use of local feed resources" MEKARN-CTU, Cantho, 23-25 May, 2005. Retrieved September 11, 2005, from http://www.mekarn.org/ctu05/chha.htm.