Development of feeding systems for rabbits and guinea pigs, based on sugar cane juice and tree foliages

A Solarte*

CIPAV, Convenio Interinstitucional para la Producción Agropecuaria en el Valle del Río Cauca, AA7482, Cali, Colombia

* IFS grantee (Research grant No: B/1126-1)

Summary

Three experiments were carried out on the feeding of sugar cane juice (preserved with either sodium benzoate or sodium metasilicate) and tree foliage (from Erythrina glauca and E peppigiana) to rabbits and guinea pigs.

The first experiment aimed to assess the acceptability of foliage from Leucaena leucocepahala and from E glauca as sources of protein to supplement the carbohydrates in the cane juice. Two growing rabbits had free access to one of these foliages and to preserved sugar cane juice. After 11 days intake of the Leucaena decreased markedly and it was replaced by Erythrina. During a further period of 100d, intakes were normal and there were no digestive problems. Intake averaged 91 g DM/d, of which 46% corresponded to the cane juice.

In the second trial, five New Zealand White male rabbits (initial weight 1240 g) were fed the cane juice and Erythrina foliage for 56 days. Average weight gains were 11.5 g/d. Intake of Erythrina increased during this period from 50% of the diet DM in the first week to 65% at the end of the trial.

The third trial was with growing guinea pigs fed comfrey (Sphytum peregrinum) foliage free choice and either (i) King grass and a commercial concentrate; (ii) derinded cane stalk and protein supplement; (iii) derinded cane stalk and foliage from E poeppigiana; or (iv) sugar cane juice and protein supplement. There were no digestive problems and no differences in growth rates (5 to 8 g/d) among the treatments.

Data are given on protein content and dry matter digestibilities (rumen nylon bag method) for a number of foliages considered to have potential value for feeding to rabbits and guinea pigs.

Key words: Rabbits, guinea pigs, sugar cane juice, forage trees, derinded sugar cane stalk, Erythrina spp.

Introduction

In Colombia, as in many other developing countries, a considerable sector of the population suffers nutritional deficiencies, especially in proteins of animal origin (milk, meat and eggs). The major factor limiting a higher consumption is the cost of these products, mainly because production systems are highly dependent on imported inputs, and therefore are not attractive to resource- poor producers.

Sugar cane juice has been used successfully in the fattening of pigs as the principal source of carbohydrates, replacing completely the cereal grains normally used for this purpose (Fermin et al 1984; Mena 1984). Cane juice has also been used experimentally in fattening of chickens, on the same basis as with pig feeding, giving the juice free choice together with restricted amounts of a protein supplement (Posso y Preston 1989).

The concept of fractionating sugar cane into highly digestible carbohydrate (the juice) for monogastric animals, and residual fibre for small ruminants, is particularly appropriate as a technological basis for intensive family farm systems (Solarte and Preston 1989).

Rabbits and guinea pigs fit well into the family farm concept, and could be the major source of animal protein for consumption by the family, the products from the other animal species being sold for cash income. As outlined by Cheeke (1986), these small herbivores have some specific advantages such as:

• Small body size, leading to reduced feed requirements, simple and low-cost housing, producing a carcass which can be consumed in a single meal by the family, eliminating the need for storage and refrigeration.
  

• Short generation interval and high reproduction rate.
  

• Use of feeds not eaten by humans, such as crop residues and byproducts, leaves from trees and shrubs.
  

• Rapid growth rate (as a function of body size).
  

• Scope for genetic improvement.
  

• The carcass meat is of high nutritional value with low fat content; valuable byproducts (skins and fur); the manure is readily used as fertilizer.

The above features are applicable both to guinea pigs and to rabbits. The former are an important livestock species in the South of Colombia, in Ecuador, in Peru and in Bolivia. Charbonneau (1988) reported there were 22 million guinea pigs in Peru, which are raised for domestic consumption accounting for up to 95% of the per caput protein intake in the Andean region. They are also bartered for other basic foods such as rice.

Trial 1

Materials and methods

This experiment was done in the experimental station of the Department of Biology of the University del Valle. The principal objective was to observe the adaptation of growing rabbits to a diet based on sugar cane juice and tree foliage.

Four rabbits of the New Zealand White breed, weighing 1800 g, were housed in individual wire metal cages. Two animals were offered fresh leaves of Leucaena leucocephala; the others were given leaves from the legume tree Erythrina glauca. Each rabbit had free access to the leaves and to fresh (or refrigerated) sugar cane juice which had been preerved with sodium benzoate (1.5 g/litre). The forages were harvested and held at ambient temperature for 24h prior to feeding. Water was also freely available.

Results and discussion

The rabbits allocated to the Leucaena treatment ate this forage well during the first days of the trial. However, by the 11th day of the trial, intake had fallen dramatically and it was decided to substitute the leucaena with Erythrina leaves, which were being consumed normally by the other two rabbits. Similar difficulties were encountered by Harris and Cheeke (1981) and Ramchurn (1978) when they attempted to replace a commercial cereal-based concentrate with high levels of Leucaena meal.

Table 1: Fresh and dry matter intakes by growing rabbits given free access to sugar cane juice and foliage from the legume tree Erythrina glauca (Mean values and SD)
	Cane juice (ml/day)	Erythrina foliage (g/day)	Total (g/day)
Fresh matter	235 ± 41	198 ± 40
Dry matter	42 ± 7	49 ± 10	91
As % of diet	46	54	100

All the rabbits continued to consume cane juice and leaves of Erythrina during a period of 100 days. There were no symptoms of digestive or metabolic upsets. Intakes of the juice and tree legume are given in Table 1. Each contributed about half of the total diet dry matter.

Trial 2

Materials and methods

This trial aimed to establish performance levels of rabbits fed the diets developed as a result of the observations made in Trial 1.

Five rabbits were used (New Zealand White) with a mean initial weight of 1240 g. Feeding and housing procedures were the same as in Trial 1, except that sodium metasilicate was used to preserve the juice at a concentration of 5 g/litre. Feed intakes were recorded daily and liveweights weekly during an experimental period of 56d. The trial was carried out in the Hacienda Arizona, Jamundi, Valle.

Results and Discussion

Table 2: Liveweights and feed intakes of growing rabbits given free access to sugar cane juice and foliage from Erythrina glauca
	Live	Weight	----------------- Feed Intakes -----------------
Week	weight (g)	gain (g)	Juice (ml/d)	Foliage (g/d)	D.M. (% of LW)
Initial	1244	-	-	-	-
1	1268	3.4	133	87	4.2
2	1333	9.3	142	159	5.7
3	1424	13.0	145	180	5.8
4	1507	11.8	148	195	5.8
5	1606	14.0	135	215	5.7
6	1669	8.5	156	277	6.9
7	1765	13.7	205	265	6.8
8	1895	18.6	223	336	7.7
Mean values		11.5	160	214	6.0

Final liveweights averaged 1900 g giving a mean daily growth rate of 12 g; rates of feed intake and growth improved as the trial progressed and this was related with an apparent adaptation to the Erythrina foliage, intake of which tripled during the period of the trial (Table 2). The contribution of the Erythrina to the total diet increased from 50 to 65% as the trial progressed.

Trial 3

It was decided to use Guinea pigs (Cavia porcellus) for this trial on the basis of their apparently greater rusticity, compared with rabbits, and their popularity as human food in much of Colombia. The animals used (n = 32; mean age 12 weeks) were crossbreds derived from indigenous (Criollo) and Peruvian strains. The trial was carried out at the Instituto Mayor Campesino (IMCA), Buga, Valle.

Contrasting sources of carbohydrate and protein were compared in a growth trial lasting 56 days. The treatments were: King grass, Comfrey (Sphytum peregrinum) foliage and 50 g/day of a cereal-rich concentrate (Control); chopped sugar cane stalk (from which the rind had been removed previously), fresh Comfrey leaves and 15 g/day of a protein supplement (40% protein) formulated for growing pigs; chopped derinded cane stalk, Comfrey leaves and leaves from the legume tree Erythrina poeppigiana; Sugar cane juice, Comfrey leaves and 15 g/day of the protein concentrate used in the second treatment. In all cases the foliages, derinded cane stalk and cane juice were given on a free choice basis. One group of two males and one group of two females were allocated to each treatment according to a 4 x 2 factorial design with two repetions.

The feeds were introduced gradually during a period of two weeks before initiating measurements of intake and growth.

Results and Discussion

The intakes of the different diet components are given in Table 3. Growth and conversion rates are given in Table 4.

Table 3: Intake of the different components of the diet given to growing guinea pigs
Treatment	Fresh matter (g/d)	Dry matter (g/d)	Protein (g/d)	Proportion of total protein (%)
Control
Grass	173	35	2.8	31
Comfrey	41	6	1.3	15
Concentrate	36	32	5.4	54
Total	250	73	11.5
Derinded cane and protein supp
Derinded cane	101	31	0.0	0
Comfrey	74	11	2.3	35
Supplement	14	13	5.0	65
Total	189	55	7.3
Derinded cane and Erythrina
Derinded cane	117	35	0.0	0
Comfrey	84	13	2.9	50
Erythrina leaves	88	18	2.9	50
Total	289	66	5.8
Cane juice and protein supp
Cane juice	117	23	0.0	0
Comfrey	90	14	3.4	40
Supplement	15	14	5.4	60
Total	232	51	8.8

Highest intakes of dry matter were encountered for animals on the control diet; the lowest intake was recorded on cane juice and protein supplement. Protein intake was highest on the control diet and least for the derinded stalk and Erythina diet.

Table 4: Growth and feed intakes of guinea pigs fed diets derived from sugar cane
	Control	Derinded stalk and suppl	Derinded stalk and Erythrina	Cane juice and Suppl
Liveweight (g)
Initial	538	478	471	478
Final	772	628	613	662
Daily gain	8.5	5.3	5	6.6
Feed intakes (g/d)
Dry matter	73	55	66	50
Protein	9.5	7.4	5.8	8.6
Feed conversion	8.7	12.8	15.7	6.9

Mean growth rates did not differ significantly among treatments but tended to be less for the derinded cane stalk treatments than for the control and cane juice treatments. Growth rate was significantly related with intake of protein (r5 = 0.83) but not with dry matter (r5 = 0.21).

Trial 4: Dry matter degradabilities of tree forages

Materials and Methods

This trial consisted of observations on the degradabilities of different tree foliages and other species, using the rumen "nylon bag" method of Orskov et al (1980).

Results and Discussion

Content of protein, and dry matter degradabilities of dry matter after 12 and 24 h in the rumen, are set out in Table 5. Based on this evaluation and on local availability, the most promising species which might be chosen for further studies for feeding to rabbits and guinea pigs are the Erythrina spp, Gliricidia sepium and Trichantera gigantea.

Table 5: Protein content and dry matter degradabilities (rumen bag method) for some forage trees found commonly in Colombia
Species	Protein content	Degradability of dry matter
	(% in DM)	% in 12 hr	% in 24 hr
Legumes
Erythrina poeppigiana	16.1	45.8	54.4
Erythrina glauca	19.5	45.8	56.0
Erythrina edulis	19.5	40.6	49.6
Inga spectabilis	15.7	29.2	34.4
Sesbania sesban	18.9	6.8	14.0
Gliricidia sepium	24.0	36.0	50.0
Cassia grandis	14.2
Cassia siamea	11.7
Mimosa farnesiana	17.8
Pseudosamanea guachapele	21.4
Crotalaria juncea	29.0
Dioclea cericea	11.2
Non-legume
Amaranthus dubius	26.5	36.2	57.2
Renealmia occidentalis	12.7	28.2	36.6
Gmelina arborea	17.3	44.2	52.0
Trichantera gigantea	16.7	52.4	60.2
Pachira acuatica	10.3

General discussion

The preliminary findings reported here indicate that it appears to be technically feasible to feed rabbits and guinea pigs with sugar cane juice and tree foliages as sources respectively of carbohydrate and protein. Growth rates obtained with rabbits on this diet were lower than has been reported with nutritionally optimum dietary regimes based on high level use of cereal-rich concentrates (see Cheeke 1987). However, it is believed that performance can be improved by selection of appropriate tree species, and/or by physical or chemical processing, so as to secure material with high palatability and increased availability of protein.

It is proposed to concentrate efforts initially on the use of the foliage from Trichantera gigantea. Although this species is not leguminous, it is nevertheless demonstrating excellent agronomic attributes of high forage yield, wide adaptability to varied soil conditions and elevations and apparently high disease resistance (E Murgueitio, personal communication). Of equal importance is the fact that the foliage from this tree is of high digestibility (Table 5) and is being consumed by pigs in quantities sufficient to balance the carbohydrates provided by sugar cane juice when both are given on a free choice basis (Mejia 1989).

Acnowledgements

These experiments were carrried out with the financial assistance of the International Foundation for Science (Research Grant No: B/1126-1) and the collaboration of Dr Graciela Valderrama de Dias, Biology Department, University del Valle; Alfonso Madriñan, owner of the Hacienda Arizona, Jamundi; Padre José Alejando Aguilar, Director of the Instituto Mayor Campesino (IMCA), Buga, Valle; and the post graduate students of CIPAV.

References

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