Evaluation of local forages for rabbits in Central Vietnam

Le Thi Lan Phuong

Faculty of animal sciences, Hue University of Agriculture and Forestry

102 Phung Hung street, Hue City, Vietnam

lelanphuong1412@Gmail.com

Abstract

Three experiments were performed to evaluate nutritive values of available forages and their inclusion in diets for rabbits kept in small holders in Central Vietnam. In the 1^st exp., 30 rabbits were fed 6 different forages (ageratum-Ageratum conyzoides, ficus-Ficus hisspida L, spanish needle-Bidens pilosa L., strawberry tree-Muntingia calabura, day flower–Commelina communis, malvaviscus–Malvaviscus penduliflorus) and found that, all forages were accepted by rabbits. In the 2^nd exp., 27 local rabbit were fed malvaviscus (MP), Day flower (DF) or spanish needle (SN) only. The results indicated that dry matter (DM) intakes was highest (P<0.05) and stable on the MP diet. In the 3^rd exp., 15 local rabbits randomly were allocated into 3 dietary treatments that included malvaviscus (MP), water spinach (WS) (Ipomae aquatica) and sweet potato vines (SP) (Ipomoea batatasn L.). The results showed that no significant DM intakes of three forages were found (71.9-83.6 g/day; P >0.05), however, CP intake was higher in diet SP than diet MP and WS (19.2 vs. 14.1. and 12.2 g CP/day, respectively). In conclusion, water spinach, sweet potato, malvaviscus are able to sole feed to rabbits and ficus, strawberry tree, and day flower could partly use in rabbit diets.

Keywords:  water spinach, sweet potato, Malvaviscus penduliflorus, Ageratum conyzoides, Ficus hisspida L, Muntingia calabura, Commelina communis

Introduction

The central Vietnam is the severe weather conditions. The inhabitant life is based mainly on small- scale farming systems. The characteristics of this system are small sized farms, integrated crop- livestock systems, low capital input and low economic efficiency.

The rabbit is a non-ruminant herbivorous animal with a satisfactory growth rate and a short production cycle (Wolfgang 1981; Cheeke et al 1987). Hence, rabbit meat expand subject has effect on small- poor farming systems (Dinh Van Binh and Nguyen Quang Suc, 1999; Hoang Van Tieu, 2006).

The rabbit meat is a good, which is of high quality with low cholesterol and therefore suitable for special diets (Owen 1981). The rabbit has an advantage over poultry and pigs because it can convert locally available plant products and by-products such as Leucaena leucocephala (Awotarowa 1992) and star grass (Cynodon plectostachyus) (Ramchurn et al 2000) into animal protein for human consumption. Hence, rabbit meat is often referred to as an inexpensive protein source (Lukefahr 1992).

The high-yield grasses are valuable feeds resource for rabbits. However, when they were planted in central Vietnam, they were not unadapted with severe weather conditions. There are very much the native plants with important resource nutrients for animals in central Vietnam because they have adaptability to severe surroundings of them (Nguyen Xuan Ba, Le Duc Ngoan, 2002).

Day flower, ageratum, ficus, spanish needle, strawberry tree, malvaviscus and sweet potato are the widespread native plants with high nutrients. The crude protein in dry matter of these feeds concentrate on from 14% to 34.4%. These trees are used as resource valuable feeds for animals in small farming systems (Duke and Ayensu. 1985; Ishida at al 2000; Nguyen Xuan Ba and Le Duc Ngoan, 2003; An le van, 2004). However, information on the nutritive value of these feeds under local conditions was lack and research had been on its utilisation by different animals particularly rabbits were very little.

Hence, there are the needs to investigate the effect on growth and nutrient digestibility of offering fresh forages of rabbits.

Objectives

* To evaluate acceptance intake of forages by rabbits

* To determine the selection and fees intake of rabbits for forages

* To determine the nutritive value and two of the most promising forages for rabbits

Materials and Methods

 Experimental feeds

The experiment feedings were general trees in Central Vietnam on the growing period. These were day flower (Commelina communis L.), ageratum (Ageratum conyzoides), ficus (Ficus hisspida L), strawberry tree (Muntingia calabur), malvaviscus (Malvaviscus penduliflorus) and spanish needle (Bidens pilosa L.), which were cut with 30-40 cm in length. Water spinach (Ipomae aquatica), sweet potato (Ipomoea batatasn L.) were conventional feeds for animals. Which were used as compare feeds.

The Dry matter (DM), organic matter (OM) and crude protein (CP) were determined according to standard methods (AOAC, 1990). The analyses of neutral detergent fibre (NDF) were done according to Van Soest et al (1991).

Animals

The local rabbits of about 2.5-3 months of age were used in experiments. Before started the experiments, the rabbits were adaptable keep and injected against external parasites with injections of Ivermectin solution (1 ml per 3 kg body weight) and vaccinated against VHD (virus haematologist disease).

The house of rabbits were constructed from wood and wire mesh. The dimensions of the cages were: width 0.5 m, length 0.6 m and height 0.4 m and facilities for feed and water. And the dimensions of the digestibility cages were: width 0.15 m, length 0.5 m and height 0.3 m and facilities for feed and water

The experiments were carried out at the Experimental farm of Hue University of Agriculture and Forestry, Hue city from December 2007 to February 2008.

Experiment 1: Study on the feeding behaviour of new forages of rabbits

Experimental design and treatments

Thirty local rabbits with an average weight of 1288 ± 35.9g were arranged in a completely randomized design with 6 treatments and 5 replications. The rabbits were kept in individual cages and fed each forages (Day flower, ageratum, ficus, spanish needle, strawberry tree and malvaviscus, respectively) on each treatment.

Offering daily each forages to rabbits in the morning at 7:00 am. The local forages were offered as bunches hanging from the side of the cage in during the time test (30 minutes). The test demand always has feed refusals in the time test. Feeds, feed selections and residues will be recorded daily during the test time. The experiment will be continuous carried 1 time per day on 5 day.

Data collection

 To determine minutes time for intake of rabbits

To record bite rate per 30 minute (times/ minute) of rabbits

Feed intake of rabbits (g/day)

Feed intake was recorded from weights of fresh materials offered minus residue taken in during the time test (30 minutes).

* From results of experiment 1, we used three of the most promising local forages (Day flower, spanish needle and malvaviscus) for next experiment

Experiment 2: Evaluation the maximum new forages intake and feed selection of rabbits

Treatments, Animals and experimental design

Twenty seven local rabbits at 3 month of age were arranged in a completely randomized design with 3 treatments and 9 replications. The dietary treatments were day flower (DF), spanish needle (SN) and malvaviscus (MP), respectively. The experimental periods lasted 14 days. The animals were fed four times a day at 7:00h, 11:00 h, 14:00h and 22:0 h). Feeds and water were available ad libitum. This experiment was done to determine selection, daily feed intake and daily weight gain of rabbits.

* From results of experiment 2, we were used malvaviscus for rabbits in next experiment.

Experiment 3: Effect of water spinach, sweet potato or malvaviscus of apparent digestibility ratios, nitrogen balance and performance in rabbits (In vivo)

Treatments, Animals and experimental design:

Fifteen local rabbits with an average weight of 1439.6±36.8g were kept in individual cages on this experiment. The animals were randomly allocated into 3 dietary treatments with 5 replicates. The each treatment diets correlative with water spinach (WS), sweet potato (SP) or malvaviscus (MP).

 After twenty experimental days, the digestibility experiment was done during 10 days,

comprising 5 days of adaptation to each diet followed by 5 days for collection of faeces and urine. The rabbits will be housed individually.

The rabbits were fed four times a day similar to experiment 2. The refused feed will be collected and recorded daily. 

Sample collection and calculations

Faeces and urine of each experimental rabbits were collected daily and stored at - 18⁰C and at the end of each experimental rabbits samples will be pooled and mixed. Sub-samples were taken and dried at 60⁰C prior to chemical analysis. The apparent digestibility ratios were calculated from the individual ratios of components to marker in the diet at the respective site of sampling. Urine was collected in a bucket containing 10 ml of 10% sulphuric acid (H₂SO₄)  to keep the pH below 4 so as to prevent escape of ammonia.

Chemical analysis

 Nitrogen determinations on urine were made on fresh samples, while the other analyses on feed, faeces will be performed on air-dry samples.

The feeds and refusals were taken for analyses of DM, OM, CP, NDF and Ash following the procedures of (AOAC, 1990) and Van Soest et al. (1991). Dry matter, OM, CP and NDF digestibility were calculated according Mc Donald (2002).

Statistical analysis

 The apparent digestibility ratios were calculated according formula:

The apparent digestibility ratios (%) = (A-B)/A*100

Where, A and B are the nutrient in feed and faeces

 Statistical analysis

Data from the experiment were analyzed by ANOVA using the General Linear Model (GLM) procedure (Minitab Version 14, 2004). Pair-wise comparisons with a confidence level of 95 will be used to determine the effects of dietary treatment between groups. Results will be presented as Least Squares Means with their pooled standard errors.

Results and discussion

Results of experiment 1: Study on the feeding behaviour of new forages of rabbits

The rabbits ate new feeds on the first day of experimental time. There were significantly differences among the fresh intakes of rabbits on the different forages on 30 minutes test (table 2). However, the average intake of dry matter was similar on all treatments (Figure 1).

The feeds intake of rabbits had deduct tendency on the next experiment days. The mean dry mater intake were higher in malvaviscus, day flower, spanish needle diets than ageratum, ficus, strawberry tree diets, but there were no significantly.

 The feeding behaviour of rabbits was observed to be eating during the 30 minutes test. The results of observation showed that:

 There were about four and five eating times on the test time (about four or five minutes at a time). The rabbits were eating highest on the first time of time test.

 The rabbits only ate a little peduncle of leaves of ageratum, while the rabbits ate a few young and tender leaves of ficus and strawberry, but feeds intake very little, some rabbits didn’t even eat. Towards malvaviscus, day flower and spanish needle, the rabbits often ate leaves and top of trees, and have the intakes were higher than ageratum, ficus and strawberry.

From these results, malvaviscus, Day flower or spanish needle were used for next experiment.

Results of experiment 2: Evaluation the maximum new forages intake and feed selection of rabbits

After 14^th experimental day, the results were given in figure 2 showed that, when do not have different nutrients, daily intake in rabbits was considerably higher to supply increased nutrients for rabbits. The daily intake of malvaviscus or day flower only to showed an upward tendency and stable, except spanish needle (figure 2).

The effect of day flower, spanish needle or malvaviscus on feeds intake and daily weight gain in rabbits is given in table 3. There were significantly difference daily intakes in rabbits between the different forages. The total mean DM intake per kg live weight was significantly lower and more changeable in rabbits fed SN compared to MP and DF. These results possibly due to comment on, when animals eat new feeds, they will eating carefully to receive the feed news. If the feed news is positive, the animals will increasing intake, and if the feed news is negative the animals will decreasing intake or stop eating (Provenza and Balph, 1990).

 In the daily weight gain trial, the malvaviscus, day flower or spanish needle were effected very high on daily weight gain in rabbit (table 3). The daily weight gain of rabbits fed MP treatment was the significantly highest, possibly due to the higher CP intake from MP treatment compared to the SN and DF treatments. Astonishingly, the CP intake of rabbits was higher in SN diet than DF diet, but daily weight gain of rabbits were negative. This result was probably due to the higher anti-nutrients and phytotoxin (β-sitosterol, triterpenes; caffeic acid(s), alkaloid, saponin…) from spanish needle effete (David Bruce Leonard, 2007) influence the live weight of rabbits. These result showed that, spanish needle had better not use for rabbit forages.

Results of experiment 3: Effect of water spinach, sweet potato or malvaviscus on feed intakes, apparent digestibility ratios nitrogen balance and performance of rabbits

 From results of experiment 2 showed that, malvaviscus could be the promising solely fed to rabbits. In this experiment, we used to malvaviscus with water spinach and sweet potato (the farmers often use these forages to rabbit feeds) were the compared feeds.

 The results are given in table 4 showed that, the daily weight gain of rabbits fed malvaviscus, sweet potato or water spinach only were significantly difference, with the highest values for rabbits were supply sweet potato only (table 4).

The daily weight gain are similar to those in study with rabbits reported by Samkol et al. (2006b); Dong et al. (2006) and Gang et al. (2006).

The data in table 4 showed that, no significantly different in DM, OM intake were found among the treatments. However, crude protein intake was significant higher in sweet potato diet than malvaviscus or water spinach diet (P<0.05).

A stonishingly, although the nutrients digestibility intake were significantly lower (p<0,005) in the malvaviscus than that in water spinach, but the daily weight gain were the significantly higher (14.6 vs. 6.1 g/day). There is a question of daily weight gain were effected by the quality ofprotein or coprophagia?

The apparent DM, OM and NDF digestibility of water spinach were higher than malvaviscus and sweet potato. Therefore, all DM, OM and NDF digestibility intake were higher in water spinach diet than malvaviscus diet and sweet potato diet. Our digestibility coefficients analyses of water spinach were lower than digestibility coefficients analyses of Doan Thi Gang et al. (2006).

 The nitrogen intake and nitrogen retention were significantly higher (P<0.05) in the malvaviscus diet than the sweet potato or water spinach diet. However, no significantly difference in storage coefficients nitrogen as percent of nitrogen intake and as percent of nitrogen digestion. The nitrogen retention as percent of intake and the nitrogen retention as percent of digestion intakes in this study were higher than range reported by Samkol et al. (2006a).

Conclusions

 Based on the results of this research it is concluded that:

 * The rabbits accepted malvaviscus, ageratum, ficus, spanish needle, strawberry tree, day flower with different intake levels on 30 minutes test and decreased intakes in 5 experimental days. The feed intake and weight gain of rabbits were highest in malvasviscus treatment.

 * Malvaviscus and sweet potato leaves have high nutritive value for rabbits as confirmed by high protein content.

 * Fresh water spinach, sweet potato, malvaviscus could be solely fed to rabbits and ageratu

m, ficus, strawberry tree, and day flower could partly use in rabbit diets.

* The rabbits fed sweet potato had weight gain was highest with the daily weight gain level was 20g/day.

 * Studies of the quality of protein of malvaviscus and effect of malvaviscus and sweet potato on eating, consumption of caecotrophes, excretion of faeces and meat performance by growing rabbits are necessary.

Acknowledgements

 The authors are grateful to the MEKARN project, financed by the Sida-SAREC agency and my assistants Dr. Le Duc Ngoan and Dr. TR Preston for their technical help. Thanks the Department of Animal science, Hue University of Agriculture and Forestry for infrastructure support.   

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