Evaluation of Calliandra foliage as a supplementary feed for rabbits fed a basal diet of Guinea grass and water spinach

Doan Thi Gang*, Khuc Thi Hue* and Nguyen Thi Mui**

* Goat and Rabbit Research Center
** National Institute of Animal husbandry, Hanoi

Abstract

In Experiment 1 sixteen lactating female New Zealand rabbits with 3.5 - 4.5 kg average body weight (BW) were used in a completely randomized design to evaluate Calliandra foliage (C) in combination with a water spinach (WS) and guinea grass (GG) basal diet. There were four treatments: Control (GG-C), consisting of guinea grass + concentrates at 3% of BW; WS + GG ad libitum (WS-GG); WS + Calliandra ad libitum (WS-C); and WS, water spinach ad libitum. The trial lasted 50 days. In Experiment 2, twenty four weaned rabbits with 450-500 g BW at 30 days of age were fed the experimental diets over a period of 80 days.

The results showed that, Calliandra contains a high crude protein (CP) content (230 g/kg dry matter (DM). The live weight losses of the rabbit dams after 30 days were 300, 600, 500 and 500g for CTL, WS-GG, WS-C and WS, respectively. The survival rates of the offspring to weaning at 30 days were better for CTL and WS-C (82 and 83%) than for WS-GG and WS (62 and 72%). The live weight gains of the growing rabbits were 19.5, 16.6, 18.8 and 17.2 g/day and the feed conversion ratios were 8.0, 5.5, 6.7 and 6.2 kg DM/kg gain for GG-C, WS, WS-GG and WS-C, respectively.

It is concluded that Calliandra foliage can be used as supplementary feed for rabbits with no loss in performance compared with concentrates.

 Key words: Calliandra foliage, growth, guinea grass, rabbits, reproduction, water spinach

Introduction

Rabbits are raised in almost all developing countries and contribute to improved nutrition and household economies, as they are both a source of animal protein, as well as providing extra income through the sale of animals. Rabbits can be given a wide variety of feeds, such as of grasses, leaves from trees, fruits, roots or by-products from the kitchen. In particular vegetables such as Water spinach and leaves from Trichanthera gigantea are relished.  Water spinach (Ipomoea aquatica) was reported to have a very high biomass yield and to contain around 28% crude protein, 12% crude fibre and 19% ash in DM of fresh leaves and stems. Water spinach has a short growth period and is resistant to common insect pests. Furthermore, results in Vietnam showed that rabbits gained 18 g/day when fed only on fresh Water spinach (Hongthong 2004).

Water spinach or Sweet potato and Guinea grass as feeds for rabbits resulted in daily gains of 26 g/day (Doan Thi Gang 2005, unpublished data). However, the limitations of these feeds are low dry mater content and the risk of diarrhoea when fed large amounts of these feeds. 

Calliandra is a relatively new feed in Vietnam, and there have been few studies carried out on its nutritive value. Calliandra has a high biomass yield (55-60 tonnes/ha) and th e leaves have high protein content (23% in DM) and can be used in cut and carry systems and as living fences. However, it has a high tannin content (14-17% in DM). The combination between Calliandra foliage and Water spinach in diets for rabbits offers an opportunity for smallholder farms by increasing the growth rate and reducing the feed conversion ratio, as well as reducing the risk of diarrhoea.

Objective

The aim of this study was to evaluate the effect of a combination between Calliandra  and Water spinach in diets for lactating and growing rabbits on intake, growth rate and milk production.

 

Materials and methods

Location and climate of the study area

The experiment was conducted at the Goat and Rabbit Research Centre, Son Tay, Ha Tay Province, Vietnam. The climate in this area is tropical monsoon with a wet season between April and November and a dry season from December to March; average annual rainfall is 1800 mm.

Experimental animals, feed and management

Sixteen New Zealand White rabbit dams were used in Experiment 1 (3.5-4.5 kg/head) and 24 weaned rabbits in Experiment 2 (450-500 g/head at 30 days of age) were selected from Experiment 1. Before starting the experiments, the rabbits were injected with Ivermectin solution (1 ml per 3 kg body weight) against external parasites and vaccinated against VHD (virus haematological disease). The feeds used in the experiments were Calliandra foliage, Water spinach and Guinea grass. The experimental feeds were cut daily in the fields around the Center and wilted for 1 hour under shade or in a house before feeding. The feeds were chopped into 20-30 cm lengths. The concentrate used in the experiment was produced by the Guyomarch factory in Vietnam and contained 87% DM and 16% CP.

Experimental design

In Experiment 1 the 16 dams were randomly allocated to 4 treatments with 4 replications. The length of this trial was 8 weeks (56 days). Twenty four weaned rabbits from Experiment 1 were chosen for the growth experiment (Experiment 2). The length of the growth trial was 8 weeks (56 days). Before starting, the rabbits were adapted to the new experimental feeds for 7 days. A completely randomized block design was used to test 4 feed combinations (Table 1).

The rabbits were offered free access to the feeds in all treatments. The amounts offered of the diets were changed following the change in body weight of the rabbits.

Measurements

The dams were weighed at the start, after giving birth, after 21 and 30 days of giving birth and oestrus activity observed after weaning. The baby rabbits were weighed around 8 hours after birth, and at 21 and 30 days of age. In Experiment 2 the weaned rabbits were weighed at the start, at the end and at 7 day intervals. The animals were weighed in the morning before feeding in both experiments. The animal cages, houses and troughs were cleaned every day.

 Analyses

The samples of feed offered and refusals were taken weekly for analysing DM, then pooled to obtain monthly samples for further analysis of CP, neutral detergent fibre (NDF), acid detergent fibre (ADF) and ash. DM was analysed according to the standard methods of AOAC (1990). Nitrogen (N) was determined by the Kjeldahl procedure. NDF and ADF were determined by the methods of Van Soest et al (1991). The data were analyzed statistically by using the GLM procedure of Minitab Software, version 13.31 (Minitab 2000). Treatment means which showed significant differences at the probability level of P<0.05 were compared using Tukey’s pair-wise comparison procedures. Milk yield was calculated according to Lebas et al (1986) [Milk yield = (P₂₁ - P₁)*1.18].

Results and discussion

The DM content ranged from 12% in water spinach to 87% in the concentrate, and was 30% in Calliandra (Table 2). The crude protein content in Calliandra was around 23% in DM.

The results in Table 3 and Figure 1 show that the daily feed intake of the dams was significantly different among treatments. The highest intake was found for treatment WS-CA, while the lowest intake was for treatments WS-GG and WS alone. The DMI expressed in kg live weight was lower and similar for control, WS-GG and WS alone compared to WS-CA. The significant difference in DM intake and the CP content of the experimental feeds resulted in significant differences of CP intake. WS intake, when in combination with other feeds was about100 g/day, and was around 200 g/day when fed alone. Supplementing with CA resulted in higher total DM intake.

The litter size at birth was from 5.3 for WS to 7.0 in GG-C (Table 4). The survival rate of the young rabbits at 30 days was not significantly different between WS-CA and GG-C. The milk yield of the dams was lower for the treatment WS-GG and WS alone compared with WS-CA and GG-C control. The estrous rate 10 days after parturition was higher and similar for treatment WS-CA and GG-C  than for WS and WS-GG .

At 30 days live weight was similar for GG-C and WS-CA, and was significantly lower for WS  and WS-GG.. 

Total daily DM intake was significantly higher in GG-C and lowest in WS-GG.  Total daily DM intake of Calliandra and Water spinach was 88 g, of which Calliandra accounted for 57%, which implies that Calliandra is very palatable for rabbits. The total daily dry matter intake in treatment WS-CA was lower than in GG-C, but was higher than for treatment WS and WS-GG Total DM intake/kg BW of WS-CA was 79 g and crude protein intake was 21.8 g, significantly higher than in GG-C and WS-GG.

The live weigh gain of the growing rabbits was highest in GG-C, followed by WS-CA and WS alone, and was lowest for treatment WS-GG (Table 6). The feed conversion ratio for WS-CA was 6.7 kg DM/ kg LWG  and 1.7 kg CP/kg LWG.

The feed cost/kg LWG of the growing rabbits was lowest for treatments WS-CA and WS alone compare to GG-C. Cost reduction over GG-C was 79 % in WS-CA, 86 % in WS and 96 % in WS-GG (Table 7).

Conclusions

Based on the results above, it can be concluded that:

• A combination of Calliandra + Water spinach did not have any negative effect on growth and reproductive performance of rabbits.

• The combination of Calliandra + Water spinach can replace a diet of guinea grass and concentrate.

• The combination of Calliandra + Water spinach reduced feed cost/kg LW and gave higher benefits for rabbit producers.

• Calliandra better than Guinea grass as a supplement to water spinach as it is higher in fibre and protein.

References

AOAC 1990 Official Methods of Analysis. Association of Official Analytical Chemists. 15^th edition (K Helrick editor) Arlington pp 1230 

Hongthong Phimmmasan,  Siton Kongvongxay, Chhay Ty and Preston T R 2004 Water spinach (Ipomoea aquatica) and Stylo 184 (Stylosanthes guianensis CIAT 184) as basal diets for growing rabbits.  Livestock Research for Rural Development. Vol. 16, Art. #34. Retrieved , from http://www.cipav.org.co/lrrd/lrrd16/5/hong16034.htm

Lebas F, Coudert P, Rouvier R and Rochambeau H de 1986 The rabbit; husbandry, health and production. FAO Animal Production and Health Series, No 21

Van Soest P J, Robertson J B and Lewis B A 1991 Methods for dietary fiber, neutral detergent fiber and non-starch polysaccharides in relation to animal nutrition.  Journal of Dairy Science 73:2583-3593

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