Effect of supplementing rice bran with sweet potato leaf meal and earthworms on growth performance of local Muscovy and Pekin ducks

Pham Tan Nha and T R Preston*

Can Tho University, VietNam
ptnha@ctu.edu.vn
* TOSOLY, AA#48, Santander, Colombia

Abstract

240 ducks, 120 of local Muscovy and 120 of Pekin ducks, from twenty-eight day-old were allocated in a Completely Randomize Design 4 groups with 3 replications for a 49 day growth trial. All birds were given a basal diet of rice bran and supplemented with sweet potato leaf meal and earthworms to replace soybean  and  dried fish.  The treatments were: 

• RB: Free access to rice bran supplemented with minerals (50% salt: 50% limestone) and vitamin premix
• RBSP: Free access to a mixture of rice bran and sweet potato leaf (60:40)
• RBSPEW: Same as RBSP but with fresh earthworms offered at 5% of the diet (DM basis) (about 5 g fresh earthworms per 100 g Live weight of the ducks).
• RBSPLM: Same as RBSP but with supplementation of synthetic lysine and methionine (quantities the same as from the earthworms).

Dry matter ( DM) intakes were higher for RB (147g/day) than  RBSPEW (140g/day) and RBSPLM (141g/day), and higher for Pekin (169g/day) than Muscovy (117g/day). Average daily weight gain were higher  for RBSPEW and RBSPLM (27 and 26 g/day, respectively) than for RB and RBSP (23g/day). Pekin ducks had higher weight gain (27g/day) than Muscovy ducks (22g/day). FCR on Muscovy ducks was better than for Pekin ducks(5.4 Vs 6.2).

Key words: Feed conversion, foliages, local resources 

Introduction

Conventional protein supplements such as soybean and fish meal have increased in price and this trend is likely to increase in future due to pressure on food supplies by the increasing population. There is a need to develop feeding systems which make greater use of feeds that are not in direct competition with human nutrition. Plants such as water spinach, duckweed and sweet potato can be grown by the farmer and the leaves which have high protein content have potential as animal feed. Limiting factors in vegetable protein are often the amino acids lysine and methionine. These can be provide from synthetic sources but they are also in high concentration in meals of animal origin such as earthworms.

One traditional crop in tropical countries is the sweet potato (Ipomoea batatas L. (Lam.)), which originated from Central America. Sweet potato is extensively grown in many countries, especially in China and Southeast Asia. In Vietnam, sweet potato is the third most important crop after rice and maize and occupied 245,000 ha in 2001 (Statistical Yearbook, 2002). Sweet potato is usually the main food crop in areas where rice production is limited, but at present it is more commonly used for livestock; both tubers   and  vines are used for pigs, poultry and cattle (Woolfe, 1992). Sweet potato based poultry  production systems are very common in Vietnam and play an important role in the economies of small farmers (Peter, 1998).

 The biomass yields of leaves, stems and tubers were found to vary according to variety, season and defoliation technique. The best options in terms of leaf and stem production were a cutting interval of 20 days and a defoliation of 50% of the total branches. Defoliation reduced tuber production. Sweet potato leaves (SPL) had a crude protein (CP) content of 25.5-29.8% in dry matter. The leaves can be used fresh, dried or as silage, and can replace fish meal and groundnut cake as a protein source for growing pigs under small farm conditions in central Vietnam (Le Van An et al 2004).

Objective

The proposed project aimed to examine the response to earthworms of ducks fed the traditional diet of rice bran when this is supplemented with leaf meal from sweet potatoes.

Materials and methods

Location, climate

The experiment was conducted in Vinh Long Province, Vietnam, during the dry season, between 01 Jan  and 15 April, 2009. Environmental temperature during the experiment averaged 27.5 °C, 35.5 °C and 27. 5°C at 6 am, 12 am. and 6 pm,  respectively.

Experimental design and treatments

240 ducks, 120 of local Muscovy and 120 of Pekin ducks from twenty-eight day-old were allocated in a Completely Randomize Design 4 groups with 3 replications for a 49 day growth trial. All birds were given a basal diet of rice bran and supplemented with sweet potato leaf meal and earthworms to replace soybean  and  dried fish.  The treatments were: 

• RB: Free access to rice bran supplemented with minerals (50% salt: 50% limestone) and vitamin premix
• RBSP: Free access to a mixture of rice bran and sweet potato leaf (60:40)
• RBSPEW: Same as RBSP but with fresh earthworms offered at 5% of the diet (DM basis) (about 5 g fresh earthworms per 100 g Live weight of the ducks).
• RBSPLM: Same as RBSP but with supplementation of synthetic lysine and methionine (quantities the same as from the earthworms).

Experimental animals, housing and management

Experimental ducks were raised in pens (4m² each pen, each pen accommodated 10 ducks) constructed in a simple house (local materials). The concrete floor was  overlaid with 10 cm of rice husks for bedding. Feeders and drinkers were put in each cage. A plastic tank were arranged for bathing.

Feed and feeding

The basal diet was prepared with rice bran supplemented with 1% minerals and vitamin premix (RB);  mixture of rice bran and sweet potato leaf meal (60:40) plus 1% minerals and vitamin premix (SP), same as SP but with fresh earthworms offered at 5% of the diet (DM basis) (SP-EW); Same as SP but with supplementation of synthetic lysine and methionine (quantities the same as from the earthworms). The ducks were fed ad libitum on each of the treatments. Feeds were offered twice daily at 07:00 am and 17:00 pm; water was freely available. 

Chemical composition of feeds

The composition of the feed ingredients is in Table 1 and of the diets in Table 2.

Measurements and chemical analysis

The ducks were weighed weekly. Feed intake was recorded daily. Samples of feeds offered were analyzed for DM and crude protein by AOAC (1990) methods.

Statistical analysis

The data were subjected to an analysis of variance (ANOVA) using the General Linear Model (GLM) procedure of Minitab 13.31. Sources of variation were: breed, diet, interaction breed*diet and error. When the F test  was significant  (P<0.05), Tukey’s test for paired comparisons was used to separate the means (Minitab 2003).

Results and discussion

Feed intake and growth rate

Dry matter intakes were higher for RB  than  SP-EW  and SP-LM (Table 3), and higher for Pekin than Muscovy (Table 4). Average daily weight gain were higher  for SP-EW and SP-LM than for RB and SP. Pekin ducks had higher weight gain but poorer feed conversion than Muscovy ducks.

Conclusions                                  

Based on the results from this trial, it can be concluded that:

• There were no benefits from supplementing of rice bran with sweet potato leaf meal
• Addition of earthworms or synthetic lysine and methionine increased growth rate on the diet of rice bran and sweet potato leaf meal,
• Pekin ducks had higher weight gain but poorer feed conversion than Muscovy ducks.

Acknowledgments

I am grateful to the MEKARN Program, financed by Sida-SAREC, for the opportunity to undertake this experiment.

References

AOAC 1990 Official Methods of Analysis. Association of Official Analytical Chemists. 15th edition (K Helrick, editor). Arlingtonpp 1230

Le Van An 2004 Sweet potato leaves for growing pigs. Doctoral diss. Dept. of Animal Nutrition and Management, SLU. Acta Universitatis agriculturae Suecia. Agraria vol. 470.

Le Van An 2004 Sweet potato leaves for growing pigs. Doctoral diss. Dept. of Animal Nutrition and Management, SLU. Acta Universitatis agriculturae Suecia. Agraria vol. 470.

Peter D 1998. Improving small-scale pig production in northern Vietnam. World Animal Review 91, 2-12

Woolfe J A 1992. Sweet potato: an untapped food resource. Cambridge University Press, Cambridge, Cambridge, 643 pp.

Go to top