Livestock Research for Rural Development 25 (4) 2013 | Guide for preparation of papers | LRRD Newsletter | Citation of this paper |
The aim of this study was to determine the effect of paddy rice supplementation on growth performance of rabbits fed a basal diet of foliage of Malvaviscus penduliflorus. Thirty five rabbits (New Zealand x Local) were arranged in a completely randomized design with 5 treatments, corresponding to paddy rice levels of 0, 1, 2, 3 and 4% of live weight. Malvaviscus penduliflorus was fed ad libitum.
There was no effect of paddy rice level on feed intake, but weight gain and feed conversion were improved almost threefold when paddy rice supplied half the diet compared with Malvaviscus foliage fed alone. Mortality was 60% when Malvaviscus foliage was the sole diet.
Keywords: feed intake, feed conversion, mortality, weight gain
Malvaviscus forage (Malvaviscus penduliflorus) usually is used as a " living" fence and ruminant feed in central Vietnam. It grows very well in many kinds of soil and is tolerant of changing climatic conditions (Nguyen Xuan Ba and Le Duc Ngoan 2003). In a preliminary study, Malvaviscus forage as the sole feed supported growth rates of 14-16g/day (Le Thi Lan Phuong 2008). The foliage is rich in crude protein (191 g/kg DM) and it was hypothesized that growth and feed conversion would be improved by supplementation with a high energy feed such as paddy rice, that has been shown to increase growth rates of rabbits fed other foliages (Tam et al 2009; Luyen et al 2012).
The experiment was carried out at the experimental farm of Hue University of Agriculture and Forestry, Hue city from September to December 2010.
Hybrid rabbits (New Zealand x Local) of about 3 months of age were used in the experiment. Before starting the experiment, they were treated against external parasites with injection of Ivermectin solution (1 ml per 3 kg body weight) and vaccinated against VHD (virus haematologic disease). They were housed in cages constructed from wood and wire mesh., with dimensions of width 0.5 m, length 0.6 m and height 0.4 m.
The treatments were levels of paddy rice of 0, 1, 2, 3 and 4% of live weight arranged in a completely random design with 7 replications.
Data collection
The rabbits were weighed at the beginning of the experiment and at seven day intervals over the trial period of 56 days. Samples of feeds offered and refused were analyzed for DM, OM, CP, NDF and ash following the procedures of AOAC (1990) and Van Soest et al (1991).
Data from the experiment were analyzed using the General Linear Model (GLM) procedure in the ANOVA program of the Minitab software (Minitab 2005) . Results are presented as Least Squares Means with their pooled standard errors.
Feed characteristics
Crude protein, ash and cell wall components were much higher in Malvaviscus foliage than in paddy rice (Table 1).
Table 1. Chemical composition of experimental feeds (% in DM except for DM which is on fresh basis) |
|||||||
|
DM |
Ash |
CP |
CF |
NDF |
ADF |
GE (kcal/kg) |
Malvaviscus foliage |
16.0 |
15.3 |
19.7 |
17.2 |
37.3 |
24.1 |
3988 |
Paddy rice |
83.6 |
4.0 |
6.3 |
11.1 |
26.7 |
14.5 |
4282 |
DM: dry matter, OM: organic matter, CP: crude protein, NDF: neutral detergent fibef, GE: gross energy |
Intake of Malvaviscus foliage declined as the offer level of paddy rice was increased (Table 2; Figure 1). This affected the overall crude protein content which declined from 19.7 to 10.9% of the diet DM as the proportion of paddy rice in the diet was increased. The effects of paddy rice supplementation on growth rate and feed conversion were dramatic, with almost three-fold improvements when the paddy rice replaced 50% of the Malvaviscus foliage in the diet (Figures 2 and 3). These improvements were reflected also in the survival data which were 100% with paddy rice supplying from 25 to 50% of the diet DM, while mortality was 60% when Malvaviscus foliage was the sole diet.
Table 2. Mean values for changes in live weight, feed intake and conversion of rabbits fed a basal diet of Malvaviscus foliage supplemented with increasing levels of paddy rice | |||||||
Parameters |
Paddy rice, % of live weight |
SEM |
P |
||||
0 |
1 |
2 |
3 |
4 |
|||
DM intake, g/d | |||||||
Paddy rice |
0.0 |
8.9 |
18.5 |
23.8 |
38.5 |
|
|
Malvaviscus |
73.7 |
66.9 |
56.8 |
53.0 |
45.4 |
|
|
Total |
73.7 |
75.9 |
75.3 |
76.8 |
83.9 |
||
CP in DM, % | 19.7 | 17.5 | 15.0 | 13.8 | 10.9 | ||
Live weight, g |
|
|
|
|
|
|
|
Initial |
832 |
773 |
742 |
659 |
725 |
54.4 |
0.452 |
Final |
1223 a |
1412 ab |
1573 bc |
1370 ab |
1720 c |
64.4 |
<0.001 |
Daily gain |
7.00 a |
11.4b |
14.8 bc |
12.7 b |
17.8 c |
0.891 |
<0.001 |
FCR |
11.5 a |
7.17 b |
5.32 bc |
5.74 bc |
4.76 c |
0.474 |
<0.001 |
Survival, % | 42.9 | 85.7 | 100 | 100 | 100 | ||
abc Means without letter in common in the
same row differ at P<0.05; |
Figure 1. Effect of paddy rice supplementation on DM feed intake of rabbits fed a basal diet of Malvaviscus foliage |
Figure 2. Effect of paddy rice supplementation on growth
rate of rabbits fed a basal diet of Malvaviscus foliage |
Figure 3. Effect of paddy rice supplementation on DM feed conversion of rabbits fed a basal diet of Malvaviscus foliage |
The beneficial effects of supplementing rabbit diets with paddy rice appear to be related to the nutritive value of the basal forage in the diet. Thus paddy rice increased growth rate by 100% when the forage source was water spinach, but this was reduced to 25% when cabbage leaves were offered together with water spinach (Tam et al 2011). When sweet potato vines was the forage the improvement from paddy rice supplementation was only 12% (Luyen et al 2012).
This study shows that Malvaviscus foliage has a low nutritive value for growing rabbits despite its apparent high palatability as DM intake was high, when it was the sole component of the diet. The implication is that there may be present some anti-nutritional compounds that negatively affect its nutritive value.
Paddy rice supplementation of Malvaviscus foliage improved growth rate and feed conversion almost three-fold compared with the foliage as the sole diet. Mortality was 60% when Malvaviscus foliage was the sole diet.
The authors are grateful to the MEKARN project, financed by Sida for financial support of the present study.
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Received 14 March 2013; Accepted 27 March 2013; Published 2 April 2013