Effect of brewery waste replacement of concentrate on the performance of local and crossbred growing

Muscovy ducks

 

Nguyen Thi Kim Dong and R Brian Ogle^*

 

 College of Agriculture,Cantho University, Cantho, Vietnam.

^* Swedish University of Agricultural Sciences, Uppsala, Sweden

 

Abstract

Feeding experiments were conducted at the experimental farm of Cantho University to determine the effects of feeding brewery waste that replaced different levels of concentrate in the diets of local and crossbred growing Muscovy ducks. A total of 300 Muscovy ducks at four weeks of age were allocated to two sets of treatments in a 2*5 factorial experiment. The first factor was breed (local Muscovy and crosses of male French Muscovy and local female Muscovy ducks). The second factor was replacement level of brewery waste for concentrate, including five different levels of concentrate (C) and with brewery waste (BW) offered ad-libitum: concentrate ad-libitum as a control diet (C100), and levels of 75 % (C75), 50 % (C50), 25 % (C25) and 0 % (C0) of the amount of concentrate consumed on the control diet, and with brewery waste ad-libitum. There were ten treatments and three replicates with ten birds per replicate (5 males and 5 females). 

 

Total daily dry matter intakes were 115 and 119g (P<0.001) for the local and crossbred ducks, respectively and 103, 118, 120, 121 and 125 g (P<0.001) for the C100, C75, C50, C25 and C0 diets, respectively. Daily weight gains were 28.4 and 29.3 g (P<0.001) for the local and the crossbred Muscovy ducks, respectively and 31.1, 30.1, 30.4, 28.0 and 25.0 g (P<0.001) for the C100, C75, C50, C25 and C0 diets, respectively. Corresponding feed conversion ratios (FCR) were 4.07 and 4.14 (P=0.083) and 3.31, 3.91, 3.94, 4.33 and 5.01 (P<0.001), respectively. The carcass weights were 1.55 and 1.74 kg and 1.80, 1.74, 1.72, 1.56 and 1.40 kg (P<0.001) for the two breeds and five diets, respectively. The best net profits were from the crossbred ducks, and ducks fed 50% concentrate (C50) with BW ad-libitum (161,000 and 166,000 VND per bird, respectively). 

 

The conclusion of the experiment is that brewery waste, a cheap locally available feed processing by-product, can be used as a feed for growing ducks to get more profits, and that crossbred (Exotic * Local) Muscovy ducks have a better potential under this production system.

 

Key words: Muscovy ducks, brewery waste, intake, growth performance.

 

Introduction

Duck production plays an important role in providing meat and eggs in the diet of the people in the Mekong Delta, where over 10 million are reared annually for egg and meat production. In recent years Muscovy ducks have been introduced and are especially popular and profitable for producers around the cities, as well as for farmers in the rural areas. The population of Muscovy ducks is about 20 % of the total number of ducks raised in the Mekong Delta (Trinh Huu Phuoc et al 1994), while crosses of Muscovy ducks are produced between male French Muscovy and female local Muscovy ducks. 

 

Muscovy ducks are easy to raise because they are more resistant to diseases and efficiently consume various local feeds to produce meaty carcasses that are sold at higher prices than local common ducks, as the dark, flavourful lean meat is particularly liked by consumers in the Mekong Delta. Therefore to meet the increasing consumer demand, there is an increasing interest in confinement of Muscovy ducks reared on locally available feeds. Moreover, Muscovy ducks are suitable for raising in urban areas as they are less active than other ducks, and are quiet and easy to breed and manage. Besides conventional feeds (cereals, soya beans and fish meal) and agricultural by–products, other locally available resources for duck raising, for example the by–products of food processing, have contributed considerably to duck production in the Mekong Delta, especially brewery waste, which is quite common and cheap.and produced almost year round in the area. The results of research in Vietnam (Nguyen Thanh Phi Long 1996) showed that people in urban and suburban areas of many provinces in the Mekong Delta have tended to utilise brewery waste as an animal feed resource to reduce feed costs.

 

The main objectives of the experiment was to determine the optimum levels of brewery waste as replacement for concentrates in diets for growing Muscovy ducks, to evaluate and compare the effect of brewery waste on the performance of local and crossbred Muscovy ducks, and evaluate the economic benefits obtained.

 

Methods and materials

Experimental design and birds

A trial was carried out using crossbred and local Muscovy ducks at the duck farm of Cantho University in the Mekong Delta. A total of 300 crossbred (male French Muscovy crossed with local female Muscovy ducks) and local Muscovy ducks at four weeks of age were used. One day old ducklings were fed a commercial diet ad-libitum from 1 to 28 days of age. The birds were identified and then individually weighed (average initial live weights were around 810 g), and weekly and slaughter weights were taken for each experimental unit. All birds were vaccinated with Duck Plague vaccine, FC3 (Pasteurellosis vaccine) at three and four weeks and given antibiotics to prevent common diseases. 

 

The experimental design was a factorial with 2 factors: duck breed, including local and crossbred (male French Muscovy crossed with female local Muscovy ducks) and diet, including five different levels of concentrate (C) and brewery waste (BW) offered ad-libitum: concentrate only as control diet (C100), and levels of 75 % (C75), 50 % (C50), 25 % (C25) and 0 % (C0) of the amount of concentrate of the control diet, and with brewery waste ad-libitum. There were therefore ten treatments and three replicates, with ten birds per replicate (5 males and 5 females). Fresh duckweed was also given at the same level of 90 g per bird per day to supply vitamins and minerals.

Diets and feeding

From day 1 to day 28 after hatching the ducklings were fed a commercial starter diet ad-libitum, which contained 12.2 MJ ME/kgDM and 19.5% crude protein (DM basis). The Muscovy ducks were kept in groups of 10  from  28 to 84 days.

 

Concentrate

The ducks were fed concentrate only as the control diet (C100), and levels of 75 % (C75), 50 % (C50), 25 % (C25) and 0 % (C0) of the amount of concentrate of the control diet. The concentrate contained 18.8 % CP (DM basis) and 12.9 MJ ME/kg DM (Table 2) The levels of CP given in the starter and finisher periods were formulated from suggested nutrient levels in practical diets for meat- type ducks (Yeong 1992). The ingredient composition of the diets and the chemical composition of the dietary ingredients are shown in Tables 1 and 2, respectively.

 

Brewery waste

The brewery waste used in the experiment was bought every day at local beer factories located near to Cantho University. The experimental ducks were supplied with feed twice a day. The refusals, spilled and remaining in the basins, were collected and weighed daily in the morning to calculate the feed intake. The concentrate feed, brewery waste and duckweed used in the experiments were analysed at the start of the experiments.

 

Duckweed (Lemna spp.)

The duckweed was cultivated on ponds enriched with nutrients from pig manure and wastewater from the duck farm of Cantho University. The duckweed was harvested daily in the early morning. After collection it was put into bamboo baskets and cleaned carefully. Fresh duckweed was supplemented once per day with the amounts given being around 900g/10ducks/day (fresh weight).

Housing and management

The ducks were confined in pens constructed from bamboo, with thatched roofs and concrete floors covered with rice straw for bedding, with an average density of 3-4 birds per m². Rectangular 15cm deep pottery basins were used as drinkers and for bathing and were cleaned twice a day before feeding. The feeders were cleaned daily in the morning.

Chemical analysis

The concentrate, brewery waste and duckweed were analysed for proximate constituents by standard methods (AOAC 1990). Analyses of neutral detergent fibre (NDF) and acid detergent fibre (ADF) were by the procedure of Goering and Van Soest (1991).

Measurements

All ten ducks in each experimental unit were weighed individually at the beginning of the experiment and then weekly and at the end of the experiment. Daily feed intakes were calculated according to the total feed consumption of the 10 ducks in each pen. At the end of the experiment, one representative female and one male bird from each pen were slaughtered for evaluation of carcass and internal organs.

Statistical analysis

The data were subjected to analysis of variance (ANOVA) by using the General Linear Model (GLM) and regression analysis of MINITAB Reference Manual Release 12 (1998).

Economic analysis

Income and total expenses (including feeds, ducklings, labour, vaccines and medicines) were calculated to derive net profit per treatment.

Results and discussion

Chemical composition of feedstuffs

The levels of CP and ME for a concentrate based diet are consistent with recommendations of Siregar et al (1982a) for growing meat-type ducks (12.7 MJ ME/kg and 16-19% CP). Analysis of amino acids showed that the most important essential amino acid concentrations in BW are higher than those of the ideal protein reported by Rose  (1997) (Table 1). The duckweed is seen to be an important source of both macro- and micro-minerals.

 

Feed intake

Intake of concentrate (g/bird/day) of the crossbred birds was significantly higher than of the local Muscovy ducks (Table 3). Intakes of brewery waste increased as concentrate supplied was reduced, reaching a maximum of 120 g DM/bird/day on diet C0 (brewery waste only) (P<0.001), indicating a high level of palatability. There was a significant difference in intake of crude protein between the two duck breeds, consumption being higher for the crossbreds (26.0 vs 25.1 g/bird/d). Intakes of CF increased with increasing BW intakes due to the high crude fibre content of BW, the highest (18.4 g) daily intake being on 100 % brewery waste (C0) (Table 3). This is consistent with studies that reported that ducks were able to consume and digest high fibre diets efficiently (Schubert et al 1982).

 

Daily weight gains and feed conversion ratios

The rate of live weight gain of the crossbred Muscovy ducks was significantly higher than that of the local birds (30.3 vs 27.4 g/bird/d), with the highest levels on C100, C75 and C50 (31.0, 30.1, 30.5 g/bird/d) and the lowest on C0 (25.0 g/bird/d) (Table 4) Rate of gain therefore was significantly depressed as brewery waste intakes increased, probably due to the high concentration of fibre in BW, which reduced nutrient digestibility. Daily gains when 50% of the concentrate was replaced by BW (over 30 g/day) were higher than results from similar trials in the Mekong Delta with growing Muscovy ducks given diets based on locally available feed resources such as paddy rice, oysters and water plants (Nguyen Thi Kim Dong 1995). Some studies have been carried out (Lopez and Carmona 1981) on brewers’ dried grains (BDG) in diets of growing chickens, with inclusion levels of 0, 10, 20, 30 and 40 %. There was a significant decrease in weight gain of birds when the inclusion of BDG was 20 % or more, whereas in our studies up to 50% BW could be included without any decrease in daily weight gains, which implies that ducks can digest high fibre diets more efficiently than chickens, as suggested by Schubert et al (1982).

 

 

 

 

Feed dry matter conversion ratio (3.31) was significantly better for the group fed only on concentrate C100 and deteriorated with increasing intakes of BW, being  highest (5.01) when no concentrate was given. These results are in agreement with reports of Dean (1985) and Yeong (1985) which showed that feed conversion ratios improved with increases in dietary energy concentration.

Carcass evaluation

Mean carcass yield of the two breeds, as well as between diets, were significantly different (P<0.001). The weights of breast and thigh muscle tended to be significantly higher on the control diet, and the 75 and 50 % concentrate diets than on the diet with only brewery waste (P<0.001 and P<0.01, respectively). There were no significant differences in weights of the components of the digestive tract, except that the weight of the gizzard increased on brewery waste diets, reaching a maximum on the C0 diet, probably, due to the large crude fibre amounts consumed. This result is consistent with the report that gizzard weights for both ducks and chickens increased with increasing amounts of fibre in the (Siregar et al 1982b), and the findings of a study on Muscovy ducks fed a high crude fibre diet based on rice bran supplemented with 30 % Azolla, which indicated that gizzard weights were significantly higher compared to ducks fed a concentrate diet (Duong Thanh Viet 1994). The effect of total daily CF intake levels on gizzard weights is shown by the following regression equation:

 

Y = 49.3 + 2.08X, r² = 0.69

Where Y = gizzard weight, g and X = CF intake, g/day.

 

Economic analysis and health status

Throughout the experiment, ducks fed brewery waste were healthy, and there were no symptoms observed of toxicity or malnutrition, even through they consumed brewery waste only. Mortality was around 1.3%.

 

Feed costs decreasing in proportion to the amount of concentrate replaced, to a minimum on the diet in which ducks were only given brewery waste. The net profits from the crossbred ducks were substantially higher than from the local ducks. The highest net benefits were for the C50 and C25 diets (166,000 VND/per bird), and ducks on the C50 diet produced an optimum carcass weight for consumers. The lowest net profit (139,000 VND) was from ducks on diet C100 as a result of the high cost of the concentrate. Therefore there would appear to be marked economic benefits to producers from using cheap brewery waste to replace concentrate in diets for growing Muscovy ducks.

 

 

 

Conclusions

It is concluded that:

• Brewery waste can replace up to 100% of concentrate diets for local and crossbred Muscovy ducks.
• A level of 50% concentrate replaced did not depress growth performance or affect carcass traits, and gave the best economic returns.
• At levels of replacement of 75 and 100% concentrate by BW, weight gains and live weights at market age were reduced but carcass quality was not influenced, and economic benefits were still better than for the concentrate only diet. 
• High levels of replacement of concentrate by BW (75 and 100 %) will be economically attractive when concentrate costs are high and this is a more sustainable production system for producers in peri-urban areas.
• Crossbreds had better performance and gave higher profits compared to the local Muscovy ducks.

 

References

 

AOAC 1990  Official methods of analysis of the Association of Official Analytical Chemist (15^th Edition.), Washington, DC  1: 69-90.

 

Dean  W F  1985  Nutrient requirements of meat-type ducks. Duck Production Science and World Practice. Farell, D  J  and Stapleton  P  (Ed). University of New England, pp. 35 – 49.

 

Duong Thanh Viet  1994  Gowth performance of local Muscovy ducks. Graduate Thesis, Faculty of Animal Husbandry and Vet  Medicine, Cantho University.

 

Goering  H  K  and Van Soest  P J 1991  Forage fibre analysis (aparatus, reagents and some applications). USDA Agri. Handbook. No. 379, National Academic, Washington DC, pp. 1-19.

 

Lopez   J  D and Carmona  J  F 1981  Feeding brewer’s dried grains. In Poultry Feed from Waste, 1994. Eds. El. Boushy  A.R.Y. Publ. By Chapman & Hall  London UK, pp. 325.

 

Nguyen Thanh Phi Long  1996  A Study  of utilizing of food processing by-products for animals in the Mekong Delta. Graduate Thesis, Faculty of Agriculture, Cantho University.

 

Nguyen Thi Kim Dong  1995  On-farm trial on the use of local available feed resources for Muscovy ducks in the Mekong Delta of Vietnam. Sarec Workshop from 12-15- 1995.

 

Rose  S P 1997  Principles of poultry Science, pp. 99-115.

 

Schubert  R, Richter  G  and Gruhn  K 1982  Comparative investigations of the digestive performance of Cairina, Pekin ducks and laying hens. Archiv fur Tierernahrung, 32, pp. 531- 537.

 

Siregar  A  P, Cumming  R B  and Farrell  D  J 1982a  The nutrition of meat-type ducks. I The effects of dietary protein in isoenergetic diets on biological performance. Aust. J. of Agri. Research 33, pp. 857-864.

 

Siregar  A  P, Cumming  R  B  and Farell  D  J  1982b  The nutrition of meat-type ducks. III The effects of fibre on biological performance and carcass characteristics. Aust. J. of Agri. Research 33, 877 – 886.

 

Yeong  S  W  1985  Utilization of local feedstuffs in diets of meat and laying ducks in Malaysia. Duck Production Science and World Practice. Farell  D. J. and Stapleton  P. (Ed). University of New England, pp. 323 – 332.

 

Yeong  S  W  1992  Advances on Feeding and Management of Ducks in Malaysia. Sustainable Animal Production: Proceedings of the Sixth AAAP animal Science Congress, Vol. II. AHAT, Bangkok, pp. 56 – 69.

 

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