Effect of access to caecotropes and supplementation with sugar cane stalk in rabbits fed a basal diet of water spinach

Sisomphone Southavong and T R Preston*

Champasack University (ChU)

Champasack province, Lao PDR

sisomphone@mekarn.org, spdeuk@yahoo.com
^*Finca Ecológica, TOSOLY, UTA (Colombia)
AA #48, Socorro, Santander, Colombia
trpreston@mekarn.org

Abstract

The experiment was conducted at Kampong Cham National School of Agriculture, Kampong Cham province, Cambodia from August 09 to September 14, 2008. Sixteen young rabbits with an initial average live weight of 744g (640 to 780g) were arranged in a completely randomized design (CRD) with 4 treatments and 4 replications. The treatments were water spinach with:  access to caecotropes; plus peeled sugarcane stalk and with access to caecotropes; without access to caecotropes (a plastic collar around the neck to prevent access to the anus); plus peeled sugarcane stalk without access to caecotropes.

Daily DM intake of water spinach and sugar cane were not effected by the rabbit having access or not to caecotropes. However, supplementation with sugar cane led to decreased intake of the stem of water spinach and replace by sugar cane stalk but they still have similar DM intake in water spinach leaves as rabbits are highly selective feeders. Crude protein intake much lower when  supplementation with sugar cane stalk as there was low crude protein contain in the sugar cane stalk. Their were no differences in growth rate of rabbits having access or not to caecotropes (P>0.05). There were no apparent advantages in supplementing the water spinach with sugar cane stalk but it could be a good advantage of supplement the sugar cane stalk with rabbit in the cool area or in the dry season while the other good feeds are not available. Moreover, there were seem to be no effect on feed conversion rates on rabbits having access or not to caecotropes and supplementation or not with sugar cane. On the other hand, The apparent DM, OM and CP digestibility coefficients were significantly higher (P<0.05) when the rabbits fed water spinach alone as the higher fiber contain in the sugar cane stalk.

It is concluded that water spinach can be given as a sole diet for growing rabbits. Supplementing fresh water spinach with sugar cane stalk appeared to confer no benefits in terms of growth rate and feed conversion in growing rabbits, but may be a beneficial when we supplement sugar cane stalk with the cool area or in the dry season that we can not find a good feed for the rabbits. The rabbits fed water spinach supplement with sugar cane stalk had a lower digestibility.

Key words: caecotrophy, digestibility, feed intake, proportion, weight gain

Introduction

In most developing, tropical countries such as Laos, Vietnam or Cambodia, farmers keep livestock like cows, buffaloes, pigs, fish and poultry for their main source of income.

Rabbit (Oryctolagus cuniculus) production is a relatively new development in the region. In recent years, their production in Vietnam has developed rapidly to meet an increased demand for fresh meat for human consumption to replace the shortfall in supplies of meat of chicken and ducks as a result of Avian Influenza (Nguyen Thi Kim Dong et al 2006). The rabbit is a non-ruminant, plant-eating animal that has the ability to consume many kinds of natural grasses, vegetables, leaves from trees, fruits and by-products from the markets.

Water spinach (Ipomoea aquatica) is a vegetable that is consumed by people and animals; it has a short growth period, is resistant to common insect pests and can be cultivated either in dry or flooded soils. Moreover, it has been found that water spinach has a high potential to convert nitrogen from biodigester effluent into edible biomass with high protein content (Kean Sophea and Preston 2001). Hongthong Phinmasan et al (2004) reported that water spinach as the only source of feed for growing rabbits appears to support acceptable growth rates of close to 20 g/day with a DM feed conversion of 2.7. This simple feeding system may be attractive for small-holder farmers in the tropics, due to the possibility to raise rabbits with a local resource (water spinach) that is easy to grow and needs no processing.

Sugarcane may be a potential feed source in subtropical and tropical areas. Its advantages as a forage crop include: 1) adaptation to the tropical and subtropical environments, 2) less sensitivity than other crops to poor soil fertility, the hot-humid climate, and insect and disease problems, 3) existing technology for its production, 4) a high yield capability, and 5) the unique ability to maintain consistent quality as a standing crop in the field (Pate et al 2002). Most importantly the yield and the quality are highest in the winter period which is when conventional feeds are scarce (Nguyen Quang Suc et al 1995).

Rabbits are herbivores and are classified as hindgut (caecum and colon) fermentors. In nature they are highly selective feeders and they can efficiently digest a wide range of simple and complex carbohydrates by curtsey of their digestive strategy. The rabbit has an efficient monogastric mode of digestion that is followed by fermentation of 'selected' cellulose feed and endogenous materials in the caecum through the action of a resident bacterial ecosystem comprised primarily of Bacteroidesspp (Leng 2006).

Hypothesis

It’s hypothesized that:

• The rabbits will had a lower feed intake and lower growth rate when they were prevented from consuming the caecotropes, and digestibility will be improved when they were prevented from consuming the caecotropes.

• The growth rate will be increased when they will be fed by  sugarcane stalk as a supplement.

Objectives                                          

• To determine effect of access to caecotropes in rabbits

• To study effect of sugarcane stalk as  supplementation feed on growth performance of rabbits fed water spinach as a basal diet

• To study the digestibility in rabbits supplementation or not with sugar cane stalk

Materials and methods

Location and duration

The experiment was conducted at Kampong Cham National School of Agriculture, Cambodia,  and was cover the period  August 09 to  September 15, 2008 (last 35 days).

Experimental design

Sixteen young rabbits with an initial average live weight of 744g (640 to 780g) were arranged in a completely randomized design (CRD) with 4 treatments and 4 replications (Table 1). 16 bamboo wooden cages were used as an individual cage for each rabbit as an experimental unit. The factors were:

• Access to caecotropes or no access
• Supplementation or not with sugar cane stalk

The individual treatments were:

• WS:                   Water spinach alone

• WSSC:              Water spinach + sugar cane stalk

• WS-C:               Water spinach + rabbits fitted with plastic collar

• WSSC-C:          Water spinach + sugar cane stalk + rabbits fitted with plastic collar

Feeding and management

The rabbits on the treatment “without access to caecotropes” are fitted with a plastic collar (Photo 4). Water spinach were bought from neighboring farmers and sugarcane stalk were bought from the local market. The diets were supplied ad libitum and offered three times a day, in the morning at 7.30 am, at 11.30 and at 4.30 pm. The leaves combined with the stems of water spinach were hung as a bunch inside the cage (Photo 3 and 4). Sugar cane stalk were peeled by hand (Photo 2) and also were hung inside the cage. Water was not supplied during the whole periods as there is sufficient moisture in the water spinach.

Animal housing

The cages were made from bamboo and wood with dimensions of width 0.5m, length 0.5m and height 0.5m. There were holes in the cage floor to let the faces go through (Photo 5).

Data collection and analyses

The rabbits were weighed every 5 days during the trial which lasted 35 days. Individual feeds and residues were recorded daily. The foliage (of water spinach) were separated into stems and leaves and the proportion were recorded every five days.  Sample of feeds (water spinach leaves and stems and sugarcane stalk) were analyzed for DM, N and Ash. In addition, the residue of feed were analyzed for DM every 5 days. The DM content were determined using the micro-wave radiation method of Undersander et al. (1993). N were determined by the Kjeldahl method (AOAC 1990). The faces of the rabbits (with no access to caecotropes) were collected during 5 days at the end of the experiment and were determined for DM content, N and Ash.

Statistical analysis

The data were analyzed according to the General Linear Model option of analysis of variance (ANOVA) using procedure of Minitab software (version 13.1). Sources of variation were access or non access to caecotropes, diets and interaction between access or non access to caecotropes*diets, and error.

Results and discussion

Feed characteristics

DM and N contents were higher in leaves compared with the stems of the water spinach (Table 2). The low N content of the sugar cane stalk probably reflected contamination with high fiber. Water spinach offered had a bigger proportion of leaves than stems (67 and 33%), and also the refusals were much higher in stems, reflecting selection for the leaf component in the foliage consumed (Table 3; Figure 2). The degree of selection for leaves was similar within the treatments, but it was lower of the feed intake of the stem when the rabbits were supplemented with sugar cane stalk (Figure 1).

Feed intake

Daily DM intake of water spinach and sugar cane was not affected by the rabbits having access or not to caecotropes (Table 3 and Figure 2). However, supplementation with sugar cane led to decreased intake of water spinach stem and replace by sugar cane stalk but they still have similar DM intake in water spinach leaves as rabbits are highly selective feeders (Figure 3). Crude protein intake much lower when  supplementation with sugar cane stalk  as there was low crude protein contain in the sugar cane stalk (Table 2).

Growth and feed conversion

Their were no differences in growth rate of rabbits having access or not to caecotropes (P>0.05). It was different result from the data of Chiv Phiny and Lampheuy Kaensombath 2006 reported that the growth rate was reduced by almost 50% when the rabbits were denied access to their caecotropes maybe because of the rabbits were still could ate their caecotropes after excreting from the anus by consuming it from the floor. There were no apparent advantages in supplementing the water spinach with sugar cane stalk (Figure 4) but it could be a good advantage of supplement the sugar cane stalk with rabbit in the cool area or in the dry season while the other good feeds are not available. Moreover, there were seem to be no effect on feed conversion rates on rabbits having access or not to caecotropes and supplementation or not with sugar cane (Table 4).

Apparent digestibility

The apparent DM, OM and CP digestibility coefficients were significantly higher (P<0.05) when the rabbits fed water spinach alone (Table 5 and Figure 6) as the higher fiber contain in the sugar cane stalk. On the other hand, feces were much harder when the rabbits were supplemented with sugar cane stalk. Figure 7 showed the response curve that

Conclusions

·        Depriving growing rabbits of access to caecotropes did not affect to DM intake, growth rate and feed conversion; and decreased DM intake of the stem when the rabbits were supplemented with sugar cane stalk.

·        Supplementing fresh water spinach with sugar cane stalk appeared to confer no benefits in terms of rate of growth and feed conversion in growing rabbits, but it may be a beneficial when we supplement or use as a basal diet with the cool area or in the dry season that we can not find a good feed for the rabbits.

·        The rabbits fed water spinach supplementation with sugar cane stalk had a lower apparent DM, OM and CP digestibility (P<0.05).

Acknowledgments

The authors would like to express their appreciation to the MEKARN program funded by SIDA-SAREC project for providing the opportunity and budget to carry out the project. Thanks are also given to Mr. Chhay Ty, Ms Latsamy and the Director of the Kampong Cham National School of Agriculture including staff members, especially Mr. Ya Rawuth (the student from the school) for their help in facilitating the execution of the experiment.

References

AOAC 1990 Official methods of analysis. Association of Official Analytical Chemists, Arlington, Virginia, 15^th edition, 1298 pp.

Chiv Phiny and Lampheuy Kaensombath 2006 Effect on feed intake and growth of depriving rabbits access to caecotrophes. Livestock Research for Rural Develop-ment. Volume 18, Article No. 34. http://www.cipav.org.co/lrrd/lrrd18/3/phin18034.htm

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. No. 34. http://www.cipav.org.co/lrrd/lrrd16/5/hong16034.htm

Kean Sophea and Preston 2001 Comparison of biodigester effluent and urea as fertilizer for water spinach. Livestock Research for Rural Development. Vol. 13 (6) http://www.cipav.org.co/lrrd/lrrd16/5/hong16034.htm

Leng R A 2006 Digestion in a rabbit – a new look at the effect of their feed and digestive strategies. Workshop on Forages for Pigs and Rabbits, Phnom Penh, 22-24 August 2006. http://www.mekarn.org/proprf/leng.htm

Nguyen Quang Suc, Dinh Van Binh, Le Viet Ly & T R Preston 1995 Studies on the use of dried pressed sugar cane stalk and fresh peeled sugar cane stalk for rabbits. Livestock Research for Rural Development. Vol. 7 (2) http://www.cipav.org.co/lrrd/lrrd7/2/qs16034.htm

Nguyen Thi Kim Dong, Nguyen Van Thu, Ogle B and Preston T R 2006 Effect of supplementation level of water spinach (Ipomoea aquatica) leaves in diets based on para grass (Brachiaria mutica) on intake, nutrient utilization, growth rate and economic returns of crossbred rabbits in the Mekong Delta of Vietnam. Workshop on Forages for Pigs and Rabbits, Phnom Penh, 22-24 August 2006. http://www.mekarn.org/proprf/kimd2.htm

Pate F M, Alvarez J, Phillips J D, and Eiland B R 2002 Sugarcane as a Cattle Feed: Production and Utilization. University of Florida, Extension Institute of Food and Agriculture Sciences. http://edis.ifas.ufl.edu/pdffiles/AN/AN04300.pdf

Undersander D, Mertens D R and Theix N 1993 Forage analysis procedures. National Forage Testing Association. Omaha pp 154.

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