Effect of supplementation on the growth and laying performance of confined and scavenging local chickens

Nguyen Thi Thuy and B Ogle*

College of Agriculture, CanTho University, CanTho, Vietnam
nthithuycn@ctu.edu.vn
^*Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Uppsala, Sweden
Brian.ogle@huv.slu.se

Abstract

A total of 225 crossbred male and female local chickens (Noi x Tau Vang) at 4 weeks of age were allocated at random to 3 treatments, and with 3 households as replications. The treatments were Control: (CPFD), total confinement, with paddy rice (P), fishmeal (F) and duckweed (D) provided ad-libitum in 3 separate feeders; SPFD: scavenging, with P, F and D provided ad-libitum and SPD: scavenging, with P and D provided ad libitum. The birds were weighed each week between 4 and 20 weeks of age and feed consumption was recorded each day throughout the growing period. Egg production and egg quality were recorded from 21 to 30 weeks of age.

Total feed dry matter (DM) and crude protein (CP) intake and average daily weight gain were significantly different among treatments (P<0.05). DM and CP intakes in CPFD (63.2 and 10.8 g/day, respectively) were higher than in SPFD (54.6 and 8.93 g/day, respectively) and SPD (47.7 and 5.01g/day, respectively). However, there were no significant differences in feed conversion ratio among treatments. Liver and gizzard weights and abdominal fat in CPFD were higher than on the other two treatments, although there were no differences in carcass yield. Hen-day production in CPFD was higher (25.4 %) than that in SPFD (21.9 %) and SPD (17.7 %) (P<0.001). However, there were no significant differences in feed consumed per egg, egg weight and egg yolk color among treatments.

Key words: Egg performance, growth performance, local chickens, scavenging, supplementation

Introduction

Chicken feed accounts for 60 to 90 % of the total production costs (Gunaratne et al 1992), In Vietnam today commercial feed prices are high in and increasing. In order to reduce the feed cost, inexpensive high protein green feeds can be supplied in the diet, such as duckweed, which has been shown to be a valuable source of protein for local chickens in the Mekong Delta (Khang and Ogle 2003). Also paddy rice is a locally available feed in rural areas of the Delta, where farmers can produce 2 or 3 crops of rice per year. Crosses between two local breeds of chicken, the Noi and Tau Vang, are commonly reared under scavenging systems in rural areas, because of their high resistance to diseases and parasites, and also because the meat fetches high prices in local markets because of its superior taste compared to commercial strains. In the rural areas of the south of Vietnam, chickens are raised traditionally in scavenging systems, but because of the risks of Avian influenza confinement systems are becoming more popular.

The objectives of the study were to evaluate the effects of including fishmeal in a basal diet of paddy rice and duckweed on feed and crude protein intake, growth rate and carcass quality of confined and scavenging growing crossbred local chickens, and on egg production, weight and yolk colour.

Materials and methods

Location

The experiment was carried out at Hamlet 9, Binh Yen Village, Long Hoa Ward in Cantho Province, located in the Mekong Delta in the south of Vietnam. Binh Yen is on an alluvial plain where there is good potential for agriculture. The experiment was conducted from April to October 2005, and included 16 weeks in the growing period and 9 weeks in the laying period.

Selection of farmers

Three households in one neighborhood of Binh Yen Village, which had relatively large gardens, a pond and fields nearby for the chickens to scavenge in were selected to participate in the experiment.

Experimental animals, treatments and design

The crossbreed (Noi x Tau Vang) chickens were reared on station to 4 weeks of age, when they were selected and allocated at random to the 3 treatments and replications, with equal numbers of males and females within treatment and household. Before being transferred to the farms, the chickens were vaccinated against Newcastle disease and Gumboro disease, and also blood samples were checked for Avian Influenza type A. The chickens on the two scavenging treatments were allowed to scavenge in the daytime from 07.00h to 17.00h, with the paddy rice, fishmeal and duckweed supplements provided separately in feeders in the scavenging area, and at night time inside the pen. The experiment had a randomized block design (RBD) with 3 treatments and 3 replicates (households) and with 25 birds / pen as experimental unit. At 20 weeks of age two representative birds per pen (one male and one female) were slaughtered for carcass evaluation.

The treatments were (Photo 1):

CPFD: Confined, with paddy rice, fishmeal and duckweed supplied ad-libitum in 3 separate feeders

SPFD: Scavenging, with paddy rice, fishmeal and duckweed supplied ad-libitum in 3 separate feeders

SPD: Scavenging, with paddy rice and duckweed supplied ad-libitum in 2 separate feeders

The chickens were confined at night in divided pens constructed from cast nets and bamboo, with floors covered with 20 cm of rice husks for bedding, and with an average density of 7 chickens/ m². The temperature inside the house averaged 26 - 33 ⁰C. Water was supplied via plastic tube drinkers situated both inside and outside the chicken house, and was available throughout the day and night. Feeders used were round plastic basins 20 cm in diameter and 25 cm high, and both feeders and drinker were cleaned and refilled daily in the morning. The chickens were released into the gardens for scavenging each morning at 07.00h, and the feeders placed outside the house. The farmers observed the chickens every day very carefully and refilled duckweed and paddy rice in the feeders as necessary. The growing chickens were weighed each week gain, and egg were collected and weighed every week.

Feed analyses and calculations

The feedstuffs were analyzed for dry matter (DM), crude protein (CP: N*6.25), crude fibre (CF), ether extract (EE), and ash, Ca and P by standard AOAC methods (AOAC 1990). Analyses of neutral detergent fiber (NDF) of the feedstuffs were also done, following the procedure of Goering and Van Soest (1970). Metabolizable energy (ME) contents of the diet ingredients were calculated from chemical analysis data using the equation of Janssen (1989).

Birds were weighed, with all 25 chickens in each pen as an experimental unit. Paddy rice and fishmeal were offered every day and the refusals were recorded every week, while duckweed was supplied twice per day and the refusals were weighed the following morning, and feed consumption calculated. Eggs were collected and weighed every week for each pen, and the feed consumption per kg eggs and mean egg weight calculated. Egg production was determined for 9 weeks of lay.

Statistical analysis

The data were subjected to analysis of variance (ANOVA) by using the General Linear Model (GLM) and regression analysis in MINITAB (1998).
 

Results

Chemical composition and nutritive value of the feeds

The DM contents of duckweed (3.02 %) and fishmeal (79.9 %) were quite low compared with reported values (Table 1), although the CP content of the fish meal used was fairly high (54.4 % in DM).

Feed and nutrient intake and growth performance

Total feed intake in CPFD (63.2 g/day) was higher than in SPFD (54.6 g/day) and SPD (47.7 g/day) (Table 2.).

Also paddy rice, fish meal and duckweed intakes in CPFD (48.9 g/day, 8.68 g/day and 5.62 g DM/day, respectively) were higher than in SPFD (44.3 g/day, 7.55 g/day and 3.02 g DM/day, respectively) and SPD (44.0 g/day and 3.67 g DM/day for P and D, respectively). As a result CP intakes in CPFD, SPFD and SPD were 10.8, 8.93 and 5.01 g / day, respectively (P<0.001). The average daily gain was higher in CPFD (12.1 g/day) than in SPFD (11.2 g / day) and SPFD (8.6 g / day) (P<0.001), but FCR were not significantly different among treatments.

Carcass evaluation and chemical composition of meat

Carcass percentage was similar among treatments [Photo 2], but liver and gizzard weights were higher in CPFD than in SPFD and SPD, the differences being more pronounced in the males (P<0.001) than in the females (Table 3). However, when expressed as a proportion of carcass weight the differences between treatments were not significant.

Feed and nutrient intakes in the laying period

Total daily feed DM and CP intakes were highest in CPFD (76.5 and 12.2 g, respectively), followed by SPFD (67.3 and 10.5 g, respectively) and SPD (61.5 and 6.70 g, respectively) (P<0.0.001) (Table 4). Paddy rice and duckweed intakes were higher in CPFD than in the two scavenging treatments (P<0.01).

Age at first egg, egg production and yolk colour

Age at first egg for the hens on SPD was 16 days later than for those on the CPFD treatment (Table 4). Hen-day production was significantly higher in CFPD (25.4 %) than in SPFD (22.0 %) and SPD (17.7 %) (P<0.01). Egg weight and egg yolk colour ("yellowness" [Photo 2]) for treatment CPFD (36.7 g and 60.1 units) were similar to SPFD (36.7 g and 57.2 units) and SPD (35.7 g and 56.1 units) (Table 4), and there were no significant treatment effects on FCR.

Discussion

The duckweed had a lower content of CP and DM than values reported by Khang (2000), probably due to the fact that it was grown in farm ponds which did not receive waste from a piggery or digester effluent, and consequently would have had a lower concentration of nutrients. This is in agreement with a later study of Khang and Ogle (2003), who found that duckweed grown on ponds enriched with digester effluent had a higher crude protein content compared to that grown on unfertilized ponds.

The fact that total DM and CP intakes were higher on the confinement treatment in both the growing and laying periods would have been a result of the scavenging chickens and hens finding a proportion of their feed from the environment, in the form of earthworms, insects, weeds, seeds and grains etc, and thus reducing their need to consume the supplements provided. The difference in DM intakes between the CPFD and SPFD treatments was 15.8% in the growing period and 13.7% in the laying period, which indicates that the birds were probably getting at around 15 % of their nutrient requirements from scavenging feed resources (SFR). The actual proportion from SFR would have been even higher, as they would have required additional energy for scavenging activities. Crude protein intakes, as a proportion of total DM intake, were 17.1% for the confined growing chickens, and 15.9 % for the layers, which confirms an earlier study carried out in Vietnam (Thuy and Ogle 2003) showing that chickens are able to balance their nutrient intakes to meet their requirements when the dietary ingredients are supplied separately. However, in the scavenging treatment with only paddy rice and duckweed provided, total CP intakes from the supplements were low, as the bulkiness of the duckweed limited DM intakes to less than 6 g per day. Duckweed intakes were higher in confinement than in the two scavenging treatments, probably because the scavenging birds also had access other green feeds, such as grass, water spinach and even the duckweed growing in the ponds. Among the scavenging treatments, there was a tendency towards a higher duckweed intake in the treatment without supplementary fish meal. Khang and Ogle (2003) also found that when the basal diet was deficient in protein, then the chickens compensated by eating more duckweed.

The significantly poorer growth performance of the birds on the SPD treatment, without fish meal, was most probably a result of the low overall CP intakes, that were only 10.5 and 10.9 % of total DM intakes in the growing and laying periods, respectively. The birds were clearly unable to make up the protein deficit from scavenging, and this is also the probable explanation for the high mortality on the SPD treatment, that was particularly high in the first week of the experiment. The lower hen-day production and higher age at first egg on the SPD treatment would also have probably been a result of this protein deficit.

The confined chickens had a deeper yellow skin than in carcasses from scavenging chickens, probably they consumed more duckweed. The observed effect on skin colour is in agreement with the results of Bui Xuan Men (2001), who observed that the meat and skin from ducks fed duckweed had a more intense yellow colour than from ducks fed diets with soya bean meal as the main protein source.
 

Conclusions

• It is concluded that the observed differences among treatments in feed and crude protein intake and growth rate and mortality were because the chickens in the scavenging treatment without supplementary fishmeal were unable to get sufficient nutrients, in particular protein, from the environment to satisfy their requirements. Similarly the higher age at first egg and lower hen-day production of the scavenging hens without access to fishmeal were probably due to a deficiency of dietary protein.

References

AOAC 1990 Official Methods of Analysis 15th edn. Association of Official Analysis Chemists. Washington, DC. Volume 1: 69-90.

Bui Xuan Men 2001 Use of Duckweed as a protein supplement for growing ducks. Doctoral Thesis. Swedish University of Agricultural Sciences. Uppsala, Sweden.

 

Gunaratne S P, Charndrasiri A D, Mangalika Hemalatha W A P and Roberts J A 1992 Feed resource base for scavenging village chickens in Sri Lanka. Tropical Animal Health Production 25. 249 -257.

 

Janssen W M A 1989 European Table of Energy Values for poultry feedstuffs. 3^rd ed. Beekbergen, Netherlands: Spelderholt Center for Poultry Research  and Information Services

Goering H K and Van Soest P J 1970 Forage fiber analysis (apparatus, reagents, procedures and some applications). Agricultural Handbook. N. 397. Pp. 1-12. ARS, USDA, Washington, DC

Khang N T K 2000 Year round study of duckweed grown on biodigester effluent. Workshop-seminar "Making better  use of local feed resources" SAREC-UAF,  January , 2000  http://www.mekarn.org/sarpro/khangct.htm

 

Khang N T K and Ogle B 2003 Effect of replacing roasted soya beans by broken rice and duckweed on performance of growing Tau Vang chickens confined on-station and scavenging on-farm  Livestock Research for Rural Development.(16) 8.  http://www.cipav.org.co/lrrd/lrrd16/8/khang16056.htm

 

MNITAB 1998 Minitab Reference Manual 1998 Release 12 for Windows, Minitab Inc. USA   

 

Thuy N T and Ogle B 2003 Studies on feed selection, growth rate and egg performance of local (Tau Vang) and improved (Tam Hoang) chickens. MSc. Thesis in the programme "Tropical Livestock Systems" . SLU, Department of Animal Nutrition and Management, P.O.Box 7024, Uppsala, Sweden.

Received 4 June 2006; Accepted 23 January 2007; Published 8 February 2007

Go to top