Teaching exotic chickens to consume local feed resources

Bounlieng Khoutsavang

National Institute of Agriculture and Forestry Research (NAFRI),
Vientiane, Lao PDR
kbounlieng@yahoo.com

Abstract

The objective of this experiment was to study the capacity of exotic chickens to learn to select local feeds when they are raised with local chickens. Eighteen exotic and six local chickens of about six weeks of age were allocated into a randomized complete block design with two replicates and two treatments consisting of groups of exotic birds (EX) or exotic and local birds (EXL) in the proportion of 1:1. There were two periods each of ten days when scavenging activity was permitted every day from 6:00 am to 17:00 pm. At the end of period I, the local birds were removed from the EXL group and the feeds on offer were restricted to broken rice and duckweed. At the end of the experiment two chickens from each treatment were slaughtered to measure the contents of the crop.

The chickens on  treatment EX, composed only of the exotic breed, consumed more soybean meal and less duckweed than those in the mixed group of local and exotic chickens (EXL).  In period II, after the local chickens were removed from group ELX, there were no differences between treatments in the composition of the selected diet which was mainly broken rice. The amounts of duckweed consumed were very low and similar to what was consumed by the exotic chicken in period I. Examination of the crop contents in the birds slaughtered at the end of period II  confirmed that the two groups of exotic birds were selecting the same ingredients.

Given free access to contrasting sources of protein (soybean meal and duckweed) exotic chickens show a greater preference for soybean meal than for duckweed, when compared with the selection pattern of local chickens. Exotic chickens given the opportunity during a ten day period to “learn” from local chickens about consuming duckweed,  had the same selection pattern (consumed only 2.5% of the diet DM as duckweed) as exotic chicken that had never had opportunity to learn from local chickens.

Key words: Exotic chicken, feed selection, local chickens, protein, scavenging behaviour
 

Introduction

Approximately 20% of the protein consumed in developing countries originates from poultry (Anonymous 2003). On the other hand, poultry production in most developing countries in based mainly on scavenging systems this input/output pratice has been a traditional component of small farmers all over the developing wordl for centuries and is thought to continue as such in the future.

Local chickens in a semi-scavenging system in Cambodia were fed broken rice alone and either fresh duckweed or ground whole soyabean offered in separate feeders (Hong Samnang 1998). Feed supplementation with either duckweed or ground soyabean increased growth rate compared with control birds, but the economical evaluation of data strongly favored the duckweed. Other observations in Vietnam (Rodriguez and Preston 1999) with local and exotic hens, in semi-scavenging system with free night-time access to either fresh duckweed or broken rice separately, or mixed together, indicated that local chickens ate much more fresh duckweed than the exotics, which in turn preferred the mixture.

Mostly, exotic breeds of chickens are raised in confinement and fed on concentrated feeds. However, for poor farmers, this system is too expensive and the use of local birds in scavenging system is generally preferred. Exotic breeds have the potential for a higher rate of production but it is generally believed that they have lost the capacity to scavenge for their feeds. It is possible that given the opportunity to learn (from peers in the same pen) they may be able to scavenge effectively. In fact, poultry have a well developed capacity to select a balanced diet from individual resources made available to them (Mastika and Cumming1985).

The aim of the study was to study the capacity of exotic chickens to learn to select local feeds when raised with local chickens.
 

Materials and methods

Location

The trial was conducted at the experimental farm of An Giang University from 05 to 26 August 2003 when the average daily temperature was:  27.1 ± 1.55 ºC (4: 00 am), 31.8 ± 2.92ºC (12.00 am) and 27.7 ± 2.37ºC (4:00 pm).

Treatments and design

The treatments were:

• EX: Exotic chickens raised alone in the pen
• EXL: Exotic chickens raised with local chickens in the same pen in the proportion of 1:1

The experiment was designed as a randomized complete block (RCB) with animal ecotype as the factor. There were 4 experimental units (2 replicates of each treatment), arranged  in 2 blocks with the two treatments randomized in each block.

Animals and housing

A total of 18 exotic and 6 local chickens of about six weeks of age were used in the experiment.

Procedure

There were two periods each of ten days. In period I, the chickens in treatments EX and EXL had free access to broken rice, soybean and duckweed offered in separate feeders. In period II, the local chickens were removed from treatment EXL and the given feeds were broken rice and duckweed for all birds in both treatments. At the end of the experiment two chickens from each treatment were slaughtered to measure the content of the crop.

Measurements

The  intake of each feed component was measured daily and samples analysed for DM and N.  Body weight of the chickens was determined every 5 days. The DM determination in feed components was carried out by microwave radiation (Undersander et al 1993) and N content was assayed as outlined by AOAC (1995) according to the Kjeldahl methodology.

Statistical analysis

The data were analyzed using the GLM option of the ANOVA software in the Minitab (Version:13.3) program. Sources of variation were: treatments and error.

Results and discussion

Mean values for feed intake and ration composition during period I (Table1) revealed that there was no significant treatment influence on daily DM intake (P>0.05). However, there was a significant effect (P<0.01) of genotype on feed selection. The chickens on  treatment EX, composed only of the exotic breed, consumed more soybean meal and less duckweed than those in the mixed group of local and exotic chickens (Figure 1). Similar differences between exotic and local chickens were reported by Nguyen Thi Khang (2001) in an experiment done in Cambodia.

Mean values for feed intake and the composition of the selected diet after the local chickens were removed from treatment ELX are given in Table 2 and Figures 3 and 4.

There were no differences between treatments in the composition of the selected diet which was mainly broken rice. The amounts of duckweed consumed were very low and similar to what was consumed by the exotic chicken in period I. Examination of the crop contents in the birds slaughtered at the end of period II (Table 4) confirmed that the two groups of birds were selecting the same ingredients.

The interpretation of these findings is that the exotic chickens had not "learned"  from the local chickens about consuming duckweed and that the higher intakes of duckweed by the mixed group of chickens in period I, probably reflected the consumption pattern of the local birds and not the exotic ones.

When the birds had access to soybean meal in period I, the protein content of the selected diet was over 30% (DM basis). In contrast, in Period II when only broken rice and duckweed were on offer, the selected diet contained only 9.3% crude protein. These differences do not support the theory that chickens will always select the combination of ingredients that provide the right balance of nutrients (Mastika and Cumming 1985).

Conclusions

Based on the results of this preliminary experiment it can be concluded that:

• Given free access to contrasting sources of protein (soybean meal and duckweed) exotic chickens show a greater preference for soybean meal than for duckweed, when compared with the selection pattern of local chickens.
• Exotic chickens given the opportunity during a ten day period to “learn” from local chickens about consuming duckweed,  had the same selection pattern (consumed only 2.5% of the diet DM as duckweed) as exotic chicken that had never had opportunity to learn from local chickens.
   

References

Anonymous 2003 Poultry production in developing countries. http://www.poultry.dk/research2003

AOAC 1995 Official Methods of Analysis. Association of Official Analytical Chemists. 16^th edition. Arlington

Hong Samnang 1999 Duckweed versus soyabean meal as a supplement for scavenge local chickens in an integrated farming system. Livestock Research for Rural Development 11(1): http://www.cipav.org.co/lrrd/11/1/sam111.htm

Mastika and Cumming R 1985 Duckweed for family poultry. Animal Production and Health 5(143):

Nguyen Thi Kim Khang 2001 Scavenging behaviour and feed selection by local and exotic chickens. Report of Mini-Project, September 2001 http://mekarn.org/MSc 2001-03/minipro/khang.htm

Rodriguez L and Preston T R 1999 Observation on scavenging local (indigenous) and Tam Hoang (exotic) chicken given free access (when confined at night) to duckweed (Lemnaceae) offered alone or mix with rice bran. Livestock Research for Rural Development 11(1): http://www.cipav.org.co/lrrd/11/1/lyl111.htm.

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