An experiment was carried out to evaluate digestibility by goats of foliage of Operculina turpethum with or without supplementation of Sesbania sesban. Four male weaned crossbred goats (Bach Thao x local female), 13 ±0.2 kg and 3-4 months of age were used. The basal diet was Operculina turpethum foliage fed ad libitum. The design was a Latin Square with 4 treatments: (i) without Sesbania (ii) supplement of Sesbania at 0.5% of body weight on dry matter basis, (iii) supplement of Sesbania at 1.0% of body weigh on dry matter basis and (iv) supplement of Sesbania at 1.5% of body weigh on dry matter basis.
Apparent digestibility of crude protein was high on all diets with a slight linear decline as the level of Sesbania was increased. DM intake and nitrogen retention showed curvilinear responses to level of Sesbania with the optimum at 1.0% of LW (as DM).
Introduction
Animal production is based on smallholder farms in the Mekong delta of Vietnam (Xuan et al 1998). The total number of goats was about 34,700 in the year 2000. The number of goat has increased to 117,110 from 2001 to 2004 (Binh et al 2001; Binh and Lin 2005). In Southern of Vietnam, goats are confined or tethered under fruit trees (Mui 2005) and are mainly kept for meat. The development of goat production in the Mekong river delta of Vietnam is limited due to the seasonal shortage of green feeds e.g. dry and flooding seasons.
Sesbania sesban (L.) Merr. is common in the wetland areas of the Mekong river delta of Vietnam. It is commonly seen growing on dikes, paddy field, along the canal sides and backyard. Sesbania sesban appears to grow best where periodic water logging or flooding is followed by a progressively drier season. Bui Phan Thu Hang et al (2011) reported that Sesbania sesban contained about 25% CP in DM and that it was a valuable supplement for weaned local goats.
Operculina turpethum is a perennial herbaceous, hairy vines growing 4 to 5 m in length. The leaves are alternate, very variable in shape, ovate, oblong and truncate or cordate at the base. The flowers are large, axillary and solitary. Fruit is a capsule with conspicuous enlarged sepals and thickened pedicles (http://en.wikipedia.org/wiki/Operculina_turpethum). Crude protein of Operculina turpethum is 16.1% in DM (Nguyen Kim Dong 2007). In practice, goat farmers reported goats fed with Operculina turperthum growing fast as compared with many traditional grasses for goats.
The aim of this experiment was to evaluate effect of feeding different proportions of Operculina turperthum forages with Sesbania sesban supplementation in the diets on intake, digestibility, and N retention of growing goats.
The experiment was done in the animal farm of Angiang University, Longxuyen city, Vietnam.
The experiment was a Latin-square design, a 4 x 4 arrangement with 4 animals, 4 periods and 4 diets. The diets were:
Operculina turpethum ad lib
Operculina turpethum ad lib + 0.5% of LW on DM basis of Sesbania sesban foliage
Operculina turpethum ad lib + 1.0% of LW on DM basis of Sesbania sesban foliage
Operculina turpethum ad lib + 1.5% of LW on DM basis of Sesbania sesban foliage
The experiment lasted for 69 days, with 4 periods consisting of 10 days of adaptation and 5 days of collection of faeces and urine, and 3 days for letting the animals move freely between periods.
The animals used in the experiment were 4 male weaned crossbred goats (Bachthao x local female). The initial weight was around 13(±0.2) kg, and age from 3 to 4 months. The experimental goats were housed in metabolism cages, de-wormed with Ivermectin, vaccinated (foot-and-mouth disease) and gradually introduced to the experimental feeds over 15 days for adaptation.
Operculina turpethum vines and Sesbania sesban foliage were hung in bunches above the fodder trough. Amounts of Sesbania sesban offered were based on individual weight at the start of each period. For the Operculina turpethum forage was fed ad libitum. Feed offered for each goat was weighed every morning and the animals were fed with 50% of their daily ration at 08:00 h in the morning and 50% at 14:00 h in the afternoon. Fresh water and mineral lick were supplied for the goats ad lib. The goat house and individual cages were cleaned daily in the morning before feeding.
During the sample collection period, feed offered, feed refusals, faeces, and urine were taken from individual animals, weighed every morning and pooled for 5 days to provide a representative sample for each goat and analysed for DM, CP and ash according to AOAC (1990), and NDF, ADF according to Van Soest and Robertson (1985).
The animals were weighed before commencement of the adaptation period and before feeding in the morning on the first day of each collection period.
The data from the experiment were subjected to analysis of variance using the General Linear Model (GLM) procedure of Minitab Software Release version 15 (2007). Sources of variation in the model were: diets, animals, periods and error.
The chemical composition of the experimental feeds is indicated in Table 1. Sesbania sesban had higher DM and CP contents than Opedrculina. NDF and ADF contents of Sesbania foliage were slightly higher than those in fresh Operculina turpethum vines.
|
Table 1. Mean values for chemical composition of the feeds (g/kg DM except for DM which is on fresh basis) |
||
|
Item |
Operculina turpethum |
Sesbania sesban |
|
DM |
146 |
231 |
|
|
|
|
|
CP |
131 |
192 |
|
OM |
885 |
926 |
|
NDF |
423 |
499 |
|
ADF |
320 |
358 |
The feed intake increased linearly as Operculina turpethum foliage was replaced by Sesbania sesban (Table 2; Figure 1). Crude protein intake increased in a similar way due to the higher content in Sesbania sesban.
|
Table 2. Feed intake of the experimental diets (least squares (LS) means and standard error (SE)) |
||||||
|
Item |
Level of Sesbania, g DM/100 g LW |
SEM |
P |
|||
|
0 |
0.5 |
1.0 |
1.5 |
|||
|
DM intake, g/day |
|
|
|
|
|
|
|
Sesbania |
0 |
79 |
153 |
217 |
|
|
|
Operculina |
453 |
402 |
395 |
339 |
|
|
|
Total |
453b |
481ab |
546a |
556a |
26 |
0.04 |
|
Intake (g/day) |
|
|
|
|
|
|
|
OM |
402b |
431ab |
494a |
507a |
22 |
0.02 |
|
CP |
61 |
69 |
82 |
86 |
7 |
0.09 |
|
NDF |
193 |
205 |
236 |
238 |
16 |
0.19 |
|
ADF |
147 |
152 |
173 |
168 |
14 |
0.52 |
|
a,b,c Means within rows with different superscripts are different at P<0.05 |
||||||
Sesbania sesban was reported as a quality nitrogen-rich feed source for goats (Sabra 2010). According to Woodward and Reed (2005), it can enable rapid fermentation because it had low fiber and negligible proanthocanidin content. The interpretation of higher intakes and digestibility on Sesbania seban may be that the foliage from this shrub is a good source of bypass protein (Preston and Leng 1987).
|
Table 3. Nutrient digestibility of the diets (Least square means and SEM) |
||||||
|
Item |
Level of Sesbania, g DM/100 g LW |
SEM |
P |
|||
|
0 |
0.5 |
1.0 |
1.5 |
|||
|
Apparent digestibility, % |
||||||
|
DM |
65.7 |
64.8 |
63.4 |
65.9 |
2.35 |
0.87 |
|
OM |
67.2 |
66.4 |
65.3 |
68.2 |
2.39 |
0.86 |
|
CP |
85.8 |
85.4 |
83.0 |
82.5 |
2.29 |
0.68 |
|
NDF |
55.7 |
53.4 |
53.4 |
54.2 |
3.98 |
0.97 |
|
ADF |
56.0 |
50.1 |
50.6 |
48.5 |
4.49 |
0.67 |
|
N balance, g/day |
||||||
|
Intake |
97 |
11.1 |
13.1 |
13.7 |
1.1 |
0.09 |
|
Faeces |
1.3b |
1.6ab |
2.2ab |
2.3a |
0.2 |
0.04 |
|
Urine |
3.8 |
4.6 |
5.4 |
6.2 |
0.6 |
0.09 |
|
Retention |
4.6 |
4.9 |
5.5 |
5.2 |
0.8 |
0.84 |
|
Retention as % N-intake |
47.0 |
42.1 |
41.3 |
38.0 |
4.29 |
0.54 |
|
a,b Means within rows with different superscripts are different at P<0.05 |
||||||
Apparent digestibility of crude protein was high on all diets with a slight linear decline as the level of Sesbania sesban was increased (Figure 2). DM intake and nitrogen retention showed curvilinear responses to level of Sesbania sesban with the optimum at 1.0% of LW on dry basis.
 |
 |
| Figure 1. Effect of level of supplementation with Sesbania sesban on DM intake of goats fed a basal diet of foliage of Operculina turpethum | Figure 2. Effect of level of supplementation with Sesbania sesban on the apparent digestibility of crude protein in goats fed a basal diet of foliage of Operculina turpethum |
 |
| Figure 3. Effect of level of supplementation with Sesbania sesban on N retention in goats fed a basal diet of foliage of Operculina turpethum |
Literature reports on the feeding of Sesbania sesban to goats have all been positive, but high saponin content in fresh foliage may lower the digestibility of nutrients according to Dorsaz (1988). This is a feasible explanation as to why when proportion of Sesbania sesban in the experimental diets was increased to 1.5% on dry basis that the DM intake, digestibility and N retention tended to decline.
By observation in practice, goat farmers collect Operculina turperthum from fallow land or in the backyard to feed for goats all year round and the growth of goats was reported fast as compared with Para grass or natural water spinach. According to Nguyen Thi Kim Dong (2007) and Bui Phan Thu Hang (unpublished), Operculina turperthum can be used as feed for rabbits in smallholder farms with good growth rate.
When given as the sole diet to goats, the foliage of Operculina turperthum resulted in acceptable feed intake, nutrient digestibility and nitrogen retention.
Replacement of Operculina turperthum with Sesbania sesban at 1.0% of body weight on a dry matter basis increased the nitrogen retention.
Binh D V and Lin N K 2005 Research and development of improved small ruminant production systems in Vietnam. In: Workshop on Small Ruminant in South East Asia. Hanoi, Vietnam, March 2nd-4th, 2005.
Binh D V, Ly N D, Mui N T and Van D T T 2001 Overview of small ruminant production in Vietnam. Small Ruminant Workshop held in the Hat Yai, November 2001.
Bui Phan Thu Hang, Vo Lam, Truong Thi Bich Phuong and Preston T R 2011 Water hyacinth (Eichhornia crassipes): an invasive weed or a potential feed for goats? Livestock Research for Rural Development, volume 23 (7), Article#152 Retrieved July 10, 2011, from http://www.lrrd.org/lrrd23/7/hang23152.htm
Dorsaz A C, Hostettmann M and Hostettmann K 1988 Molluscicidal saponins from Sesbania sesban. Planta Medica 54, 225-227.
Operculina turpethum biology, from http://en.wikipedia.org/wiki/Operculina_turpethum
Mui N T 2005 Country pasture/forage resource profiles, from http://www.fao.org/WAICENT/FAOINFO/AGRICULT/AGPC/doc/counprof/vie
Nguyen Kim Dong 2007 Utilisation of local available feeds for rabbits. BSc. Thesis of Animal Husbandry and Veterinary Medicine. Cantho University.
Preston T R and Leng R A 1987 Matching ruminant livestock systems with available resources in the tropics and sub-tropics. Penambul Books, NSW, Australia.
Sabra H A, Hassan S G and Mohamed M I 2010 Effect of Sesbania sesban supplementation on the reproductive performance of Baladi sheep as compared to Berseem (Egyptian clover). Journal of Reproductive and Infertility 1(3): 66-70
Woodward A and Reed J D 1997 Nitrogen metabolism of sheep and goats consuming Acacia brevispica and Sesbania sesban. Journal of Animal Science, 75:1130–1139
Xuan V T and Sanh N V 1998 History and future development of Farming systems in the Mekong Delta of Vietnam. Development of Farming Systems in the Mekong Dela of Vietnam. Jircas, CTU and CLRRI. pp. 21-22.