Pig production is one of the major priorities for rural development in Vietnam. The pig population (Table 1) in Vietnam increased by 6.0% annually from 2000 to 2005 (General Statistical Organization, 2005, cited by Kinh and Hai, 2006). It has been estimated recently that around 80% of the total pig population are raised in traditional smallholder systems (Lapar et al 2003). Commercial feeds are rarely used in smallholder farms because these are expensive, and therefore diets are mainly based on rice bran, broken rice, maize, vegetables, and agricultural by-products, like sweet potato vines, cassava leaves, cassava residue, non-dehulled groundnut cake, and other locally available by-products, which are characterised by a high fibre content and low protein and energy contents (Loc et al 1996). When included at high levels, these may decrease the digestibility of energy and other dietary components (Fernandez and Jørgensen, 1986; Noblet and Le Goff, 2001; Len et al 2006a,b) and result in low performance.
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Table 1. Livestock population in Vietnam 2000 – 2005 (million) |
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|
2000 |
2001 |
2002 |
2003 |
2004 |
2005 |
Annual growth (%) |
|
Pigs |
20.2 |
21.8 |
23.2 |
24.9 |
26.1 |
27.4 |
6 |
|
Poultry |
196 |
218 |
233 |
254 |
218 |
220 |
2.02 |
|
Cattle |
4.13 |
3.90 |
4.06 |
4.39 |
4.91 |
5.54 |
5.7 |
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Source: General Statistical Organization, 2005 |
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Today, exotic breeds such as the Landrace, Yorkshire and Duroc have developed rapidly (Ly, 2000), especially in the urban areas of Vietnam, due to the tendency towards rearing exotic pigs to meet the higher demand of consumers for both quantity and quality of meat. However, the Mong Cai (MC) breed has better characteristics with regards to reproduction, is adapted to the hot climate and is more tolerant of high-fibre diets than exotic breeds (eg. Landrace x Yorkshire, LY). Recently, Khieu Borin et al (2005) and Len et al (2006a) indicated that MC pigs can utilize diets containing high fibre levels more efficiently than improved breeds. On the other hand, Ly et al (1998) and Kemp et al (1991) did not observe any effect of breed on the digestibility of dietary components in high-fibre diets.
Young pigs have a limited ability to effectively utilize diets containing lower quality ingredients with high fibre content. Besides, pigs do not secrete endogenous enzymes that break down plant fibre (Fernando and Feuchter, 2004). However, by adding enzymes to feed, the digestibility of the components can be enhanced, leading to greater efficiency in the production of animal products such as meat and eggs. Some studies have shown that dietary enzyme supplementation for pigs improved the nutrient digestibility as well as performance (Suga et al 1978; Omogbenigun et al 2004; Xia Meisheng, 2000). Feed enzymes in diets would be expected to work more efficiently for piglets (Thomke and Elwinger, 1998) and when matched to specific target substrates (Bach Knudsen, 1997).
The objective of this study was to evaluate the effect of fibrous diets, with or without enzyme supplementation, on ileal and total tract digestibility and performance of local (Mong Cai, MC) and exotic (Landrace x Yorkshire, LY) weaned piglets.